Monday, July 20, 2009
Herbal Treatment for Cervical Cancer
Herbal Treatment for Cervical Cancer
Contributor
By Randi Cardoza
eHow Contributing Writer
Any form of cancer is scary but for women, cancers of the reproductive organs are almost undetectable without the use of regular visits and testing by her doctor. According to the AmericanChronicle.com article "Herbal Medicines for Cervical Cancer," women between the ages of 30 and 55 have the highest incidence of cervical cancer. The article recommends, after diagnosis, garlic and ginseng herbal therapy along with a healthy lifestyle can help treat the cancer.
Garlic
Garlic has long been displayed as being heart healthy. In addition, AmericanChronicle.com says, "Garlic has been shown to inhibit the growth of cancer cells while promoting the production of healthy cells." Allicin, an antioxidant found in garlic, was presented to the 34th annual Conference of Clinical Biochemists of India in December 2007 by Irfan Ahmad Ansari and Najmul Islam and found to have "reduced cell viability to 27 percent after 24 hours of treatment." Plus, in concurrence with Ansari and Islam's findings, the governmental publication Environmental Health Perspectives said in September 2001 that "Garlic powder in the diet inhibited mammary tumors... and a garlic extract decreased the incidence of cervical carcinoma..."
Ginseng
MayoClinic.com expert and medical oncologist Timothy Moynihan, M.D. says: "A 2007 pilot study at Mayo Clinic suggested that American ginseng may be an effective treatment for cancer-related fatigue." Aside from fighting the fatigue, the AmericanChronicle.com says: "Ginseng also is known for its immunity-boosting, anti-cancer properties." But ginseng alone may not alone treat cervical cancer. The ImmunoPower.com article "Nutrition in Cancer Treatment" states that "Panax ginseng was able to enhance the uptake of mitomycin (an antibiotic and anti-cancer drug) into the cancer cells for increased tumor kill."
Healthy Lifestyle
This is not an herbal treatment by any means. But according to the National Cancer Institute, "Regular exercise and a healthy diet may be protective factors for some types of cancer." The non-profit resource HelpGuide.org article "Cancer Prevention Diet and Nutrition: Guide to Foods that help Prevent Cancer" claims that 30 to 40 percent of cancers are directly linked to dietary choices, according to a 1997 report underwritten by the American Institute for Cancer Research." Simply put, by getting rid of foods with unpronouncible additives and eating more natural foods, you can prevent different kinds of cancer altogether. The article recommends a well-rounded diet of fruits and vegetables, whole grains, lean protein, low fat dairy and healthy fat sources.
Source: http://www.ehow.com/way_5154330_herbal-treatment-cervical-cancer.html
Contributor
By Randi Cardoza
eHow Contributing Writer
Any form of cancer is scary but for women, cancers of the reproductive organs are almost undetectable without the use of regular visits and testing by her doctor. According to the AmericanChronicle.com article "Herbal Medicines for Cervical Cancer," women between the ages of 30 and 55 have the highest incidence of cervical cancer. The article recommends, after diagnosis, garlic and ginseng herbal therapy along with a healthy lifestyle can help treat the cancer.
Garlic
Garlic has long been displayed as being heart healthy. In addition, AmericanChronicle.com says, "Garlic has been shown to inhibit the growth of cancer cells while promoting the production of healthy cells." Allicin, an antioxidant found in garlic, was presented to the 34th annual Conference of Clinical Biochemists of India in December 2007 by Irfan Ahmad Ansari and Najmul Islam and found to have "reduced cell viability to 27 percent after 24 hours of treatment." Plus, in concurrence with Ansari and Islam's findings, the governmental publication Environmental Health Perspectives said in September 2001 that "Garlic powder in the diet inhibited mammary tumors... and a garlic extract decreased the incidence of cervical carcinoma..."
Ginseng
MayoClinic.com expert and medical oncologist Timothy Moynihan, M.D. says: "A 2007 pilot study at Mayo Clinic suggested that American ginseng may be an effective treatment for cancer-related fatigue." Aside from fighting the fatigue, the AmericanChronicle.com says: "Ginseng also is known for its immunity-boosting, anti-cancer properties." But ginseng alone may not alone treat cervical cancer. The ImmunoPower.com article "Nutrition in Cancer Treatment" states that "Panax ginseng was able to enhance the uptake of mitomycin (an antibiotic and anti-cancer drug) into the cancer cells for increased tumor kill."
Healthy Lifestyle
This is not an herbal treatment by any means. But according to the National Cancer Institute, "Regular exercise and a healthy diet may be protective factors for some types of cancer." The non-profit resource HelpGuide.org article "Cancer Prevention Diet and Nutrition: Guide to Foods that help Prevent Cancer" claims that 30 to 40 percent of cancers are directly linked to dietary choices, according to a 1997 report underwritten by the American Institute for Cancer Research." Simply put, by getting rid of foods with unpronouncible additives and eating more natural foods, you can prevent different kinds of cancer altogether. The article recommends a well-rounded diet of fruits and vegetables, whole grains, lean protein, low fat dairy and healthy fat sources.
Source: http://www.ehow.com/way_5154330_herbal-treatment-cervical-cancer.html
Some Facts About Biotin
Biotin
Also Known as: Conenzyme R or Vitamin H
[Source: http://www.nutriherb.net/biotin.html]
Biotin Facts
Biotin is a water soluble vitamin and a member of the B-complex family, and it is essential for the normal metabolization of fat and protein. It should be noted that raw eggs prevent absorption of this vitamin by the body, commonly referred to as the "egg white injury factor". Biotin is also produced by bacteria in the large intestine, although it's unknown how much is absorbed and utilized by the body. Biotin works synergistically with Vitamins B-2, B-3, B-6, and Vitamin A to maintain healthy skin, nails, and hair, as well as many other important functions.
How Biotin Works
Biotin activates enzymes that are responsible for splitting and rearranging glucose, amino acids, and fatty acid molecules. It plays a major role in energy production and the synthesis of nonessential amino acids and fatty acids. Biotin is involved in the breakdown of carbohydrates, fats, and proteins, and it helps promote healthy nails and hair.
Possible Benefits
Alleviates eczema and dermatitis
Assists metabolism of carbohydrates, fats, and proteins
Plays major role in energy production
Eases muscle pains
Promotes healthy skin, nails, and hair.
May help people with diabetes by increasing body's response to insulin and keeping low blood sugar levels.
Increases thickness of nails and improves weak and brittle qualities
May protect agains nerve damage associated with diabetes
Usage Guidelines
The RDA for biotin is 300 mcg a day, but there are no known adverse effects from high dosages. Biotin deficiency is rare, but symptoms may include dermatitis, mental changes, muscle pain, nausea and loss of appetite.
Some Natural Sources
Brewer's yeast, beef liver, eggs, milk, kidney, rice, soy products, oatmeal, barley, legumes, cauliflower, whole wheat and grains, peanuts, walnuts, pecans, peanut butter, strawberries, watermelon, banana, cantaloupe, grapefruit, raisins, peach, tomato, potato, zucchini, corn, and spinach
Also Known as: Conenzyme R or Vitamin H
[Source: http://www.nutriherb.net/biotin.html]
Biotin Facts
Biotin is a water soluble vitamin and a member of the B-complex family, and it is essential for the normal metabolization of fat and protein. It should be noted that raw eggs prevent absorption of this vitamin by the body, commonly referred to as the "egg white injury factor". Biotin is also produced by bacteria in the large intestine, although it's unknown how much is absorbed and utilized by the body. Biotin works synergistically with Vitamins B-2, B-3, B-6, and Vitamin A to maintain healthy skin, nails, and hair, as well as many other important functions.
How Biotin Works
Biotin activates enzymes that are responsible for splitting and rearranging glucose, amino acids, and fatty acid molecules. It plays a major role in energy production and the synthesis of nonessential amino acids and fatty acids. Biotin is involved in the breakdown of carbohydrates, fats, and proteins, and it helps promote healthy nails and hair.
Possible Benefits
Alleviates eczema and dermatitis
Assists metabolism of carbohydrates, fats, and proteins
Plays major role in energy production
Eases muscle pains
Promotes healthy skin, nails, and hair.
May help people with diabetes by increasing body's response to insulin and keeping low blood sugar levels.
Increases thickness of nails and improves weak and brittle qualities
May protect agains nerve damage associated with diabetes
Usage Guidelines
The RDA for biotin is 300 mcg a day, but there are no known adverse effects from high dosages. Biotin deficiency is rare, but symptoms may include dermatitis, mental changes, muscle pain, nausea and loss of appetite.
Some Natural Sources
Brewer's yeast, beef liver, eggs, milk, kidney, rice, soy products, oatmeal, barley, legumes, cauliflower, whole wheat and grains, peanuts, walnuts, pecans, peanut butter, strawberries, watermelon, banana, cantaloupe, grapefruit, raisins, peach, tomato, potato, zucchini, corn, and spinach
Top Ten Best-Researched Herbs
Natural Health and Longevity Resource Center
Top Ten Best-Researched Herbs
by Steven Taormina
Beautiful to behold in nature, many plants have been used medicinally for thousands of years. Here are ten proven medicinal herbs that scientists have tested in clinical studies. Few people are aware of the multitude of scientific studies done on plants. This information should not be used as medical advice.
Garlic
"If we were to design a drug that had perfect properties according to what we know about heart disease and associated risk factors, we couldn't improve on garlic," says Amanda McQuade-Crawford, herbalist and director of the Ojai Center of Phytotherapy in Ojai, Calif. Regular use of garlic is associated with the prevention of cardiovascular disease, she explains. Garlic raises protective HDLs (high-density lipoproteins), while it lowers harmful LDLs (low-density lipoproteins) and triglycerides (blood fats). Garlic is also known to help lower high blood pressure, she says. Garlic aids in cancer prevention by raising the body's level of glutathione transferase, a liver enzyme known to detoxify the body of carcinogens, says McQuade-Crawford. In China, researchers found gastric cancer was reduced where garlic intake was high. Other researchers have noted improved helper/suppressor ratios of T-cells in AIDS patients who take garlic. Proven to work against various micro-organisms including bacteria resistant to antibiotics, garlic is known to be antifungal and antiviral, she adds.
Hawthorn
The berries of this flowering shrub are best used for the heart, says McQuade-Crawford. Hawthorn aids the heart's pumping action by opening the coronary arteries to nourish the heart muscle. The herb can also slow a rapid heart rate and strengthen a failing heart. Hawthorn usually lowers high blood pressure, especially a raised diastolic high blood pressure, and it benefits low blood pressure due to weak heart muscles with arrhythmia (irregular heart rhythm).
"Hawthorn takes a long time to do its best -- six months or longer. In the style of a true herbal tonic, it can be taken safely and effectively over time for its best effects," notes McQuade-Crawford.
Ginkgo Biloba
Ginkgo Biloba extract from the ginkgo tree has been shown to benefit visual function by improving microcirculation to the eyes especially among patients suffering from senile macular degeneration, a common condition thought to involve free radical damage, says Steven Schechter, N.D., author of Fighting Radiation & Chemical Pollutants With Foods, Herbs &Vitamins (Vitality, Ink).
More than 280 scientific studies indicate standardized ginkgo extract prevents and/or benefits ailments such as vertigo, tinnitus, inner ear disturbances, memory impairment, ability to concentrate, anxiety, depression, neurological disorders, senility, circulatory disorders, edema and Raynaud's disease (a vascular disorder). Ginkgo extract improves the quality and increases the quantity of capillary circulation, thus increasing blood flow to the brain, heart and tissues in organs and glands, Schechter says. In addition, he notes, the flavonoids in ginkgo are potent free radical scavengers.
Ephedra
Also known in Chinese as ma huang, ephedra may be the world's oldest herb cultivated for medicinal purposes, dating back nearly 5,000 years, says McQuade-Crawford. It's commonly used in cold formulas as a decongestant.
"Ephedra is a great bronchial dilator," McQuade-Crawford says. It helps asthma sufferers by opening the sinus passages and has an antihistamine effect which aids chronic and acute allergies. Ephedra also acts as a circulatory stimulant to blood pressure and heart function; it elevates blood pressure. Ephedra's main constituent is ephedrine, which increases adrenaline secretion in our bodies. The boost you get from ephedra stimulates certain glands, muscles and tissue functions, while it suppresses others.
"In the long term, ephedra's adrenaline overdrive can lead to chronic stress and even to degenerative disease," warns McQuade-Crawford. She notes this is important for people using ephedra for dietary weight loss or "pep pill" purposes because the effects of ephedra linger in the body long after the herb is gone. "Ephedra shouldn't be used with drugs for the heart or for the lungs and never with antidepressant drugs. It's not for use with the weak or the ill and when used long term, dosages should be conservative," McQuade-Crawford cautions.
Licorice
Licorice has been most recently researched as an antiviral and in the treatment of gastrointestinal ulceration, explains McQuade-Crawford. Its soothing, anti-inflammatory and relaxing actions help smooth muscles in the gastrointestinal tract on contact. "Licorice gets into a painful, contracted, tight digestive tract and coats the raw places, relaxes the clenched-up muscles and acts as a local anti-inflammatory," she says. Licorice also increases bile secretion. Licorice is indicated for any gastrointestinal ulcers, including mouth ulcers. The root is indicated for chronic coughs and bronchitis as a soothing decongestant. It's also indicated in small amounts to reduce sugar cravings.
The Chinese often use licorice to improve the taste and the effects of other herbs in complex formulas. Japanese research has shown licorice to decrease high testosterone levels in women with ovarian cysts and to increase their fertility. Large amounts of licorice or long-term use raises blood pressure in some people.
Bilberry
A strong antioxidant, bilberry benefits your circulatory system, eyes, heart and brain, and helps generate overall good health, says Schechter. Bilberry fruit contains a type of flavonoid called anthocyanosides, which are responsible for increasing flexibility of capillaries and increasing blood flow.
Research shows that standardized extract of bilberry can enlarge range of vision and improve sharpness of images, enhance ability to focus, and improve blurred vision, eyestrain and nearsightedness. Bilberry extract also helps strengthen coronary arteries and helps prevent atherosclerosis and venous insufficiency, which causes swollen ankles and feet. "Since adding bilberry to my own health program, I've noticed my muscles seem to recover slightly faster, I experience less muscular pain and my vision has improved from 20/100 to approximately 20/50," says Schechter.
Echinacea
Decades of research prove echinacea's value for aiding the immune system, Schechter explains. Studies have determined echinacea's ability to activate white blood cells and stimulate the regeneration of the cellular connective tissue and the epidermis. Schechter notes that echinacea's infection-fighting properties stem from its ability to neutralize a harmful enzyme involved in the infection process. Echinacea also increases two vital components of your immune system that consume and eliminate invading organisms and foreign particles.
German studies have shown echinacea extract contains proteins that help protect noninfected cells against viral infections, one reason why echinacea is regarded as an influenza preventor. Another German study found echinacea effective in allergy treatment because it helps prevent tissue inflammation due to harmful foreign toxins.
Milk Thistle
"I consider standardized milk thistle seed extract the most beneficial herbal product for liver detoxification, regeneration and protection, and, in general, one of the most universally necessary herbal products for the 1990s," says Schechter. He notes that the stress of toxins from chemical pollutants, pharmaceuticals, alcohol, tobacco smoke, drugs and different forms of radiation have cumulative side effects that need to be addressed.
More than 120 scientific studies have shown that milk thistle extract regenerates, regulates and strengthens liver functions. Because free radicals attack the liver, primarily the fat tissue in the liver, the antioxidant qualities of milk thistle are extremely beneficial. Milk thistle stimulates your body to produce superoxide dismutase, which is one of two primary antioxidants the body can manufacture.
Astragalus
Astragalus has been used as an immunity booster in China for nearly 4,000 years, according to Rob McCaleb, founder of the Herb Research Foundation in Boulder, Colo. Astragalus extracts can increase immune system efficiency by increasing immune activity. One study found that astragalus extracts could increase the impaired immune function of blood cells up to and sometimes beyond normal cell ability.
According to Planetary Herbology (Lotus Press) by Michael Tierra, N.D., astragalus helps strengthen digestion, raise metabolism, strengthen the immune system and promote wound healing. It can also treat chronic weakness of the lungs, shortness of breath, low energy, prolapse of internal organs, spontaneous sweating, chronic lesions and deficiency edema.
Ginseng
Ginseng is one of the most widely studied herbs, having been the subject of more than 3,000 scientific studies to investigate how ginseng helps improve a person's physical and/or mental performance, notes McCaleb. Studies have shown ginseng helps increase memory and learning by improving circulation. It's also been shown to reduce cholesterol and protect the liver from toxins. Ginseng, according to Tierra, is known to strengthen the lungs, nourish body fluids and calm the spirit. It may be used for shock, collapse and heart weakness, as well as for promoting longevity and increasing resistance to disease.
A Japanese study showed cancerous liver cells could be reverted to normal cells in a Petri dish culture when treated with Panax ginseng extract. Siberian ginseng has also been shown to stimulate the immune system.
Source of this document: http://www.all-natural.com/top-ten.html
Top Ten Best-Researched Herbs
by Steven Taormina
Beautiful to behold in nature, many plants have been used medicinally for thousands of years. Here are ten proven medicinal herbs that scientists have tested in clinical studies. Few people are aware of the multitude of scientific studies done on plants. This information should not be used as medical advice.
Garlic
"If we were to design a drug that had perfect properties according to what we know about heart disease and associated risk factors, we couldn't improve on garlic," says Amanda McQuade-Crawford, herbalist and director of the Ojai Center of Phytotherapy in Ojai, Calif. Regular use of garlic is associated with the prevention of cardiovascular disease, she explains. Garlic raises protective HDLs (high-density lipoproteins), while it lowers harmful LDLs (low-density lipoproteins) and triglycerides (blood fats). Garlic is also known to help lower high blood pressure, she says. Garlic aids in cancer prevention by raising the body's level of glutathione transferase, a liver enzyme known to detoxify the body of carcinogens, says McQuade-Crawford. In China, researchers found gastric cancer was reduced where garlic intake was high. Other researchers have noted improved helper/suppressor ratios of T-cells in AIDS patients who take garlic. Proven to work against various micro-organisms including bacteria resistant to antibiotics, garlic is known to be antifungal and antiviral, she adds.
Hawthorn
The berries of this flowering shrub are best used for the heart, says McQuade-Crawford. Hawthorn aids the heart's pumping action by opening the coronary arteries to nourish the heart muscle. The herb can also slow a rapid heart rate and strengthen a failing heart. Hawthorn usually lowers high blood pressure, especially a raised diastolic high blood pressure, and it benefits low blood pressure due to weak heart muscles with arrhythmia (irregular heart rhythm).
"Hawthorn takes a long time to do its best -- six months or longer. In the style of a true herbal tonic, it can be taken safely and effectively over time for its best effects," notes McQuade-Crawford.
Ginkgo Biloba
Ginkgo Biloba extract from the ginkgo tree has been shown to benefit visual function by improving microcirculation to the eyes especially among patients suffering from senile macular degeneration, a common condition thought to involve free radical damage, says Steven Schechter, N.D., author of Fighting Radiation & Chemical Pollutants With Foods, Herbs &Vitamins (Vitality, Ink).
More than 280 scientific studies indicate standardized ginkgo extract prevents and/or benefits ailments such as vertigo, tinnitus, inner ear disturbances, memory impairment, ability to concentrate, anxiety, depression, neurological disorders, senility, circulatory disorders, edema and Raynaud's disease (a vascular disorder). Ginkgo extract improves the quality and increases the quantity of capillary circulation, thus increasing blood flow to the brain, heart and tissues in organs and glands, Schechter says. In addition, he notes, the flavonoids in ginkgo are potent free radical scavengers.
Ephedra
Also known in Chinese as ma huang, ephedra may be the world's oldest herb cultivated for medicinal purposes, dating back nearly 5,000 years, says McQuade-Crawford. It's commonly used in cold formulas as a decongestant.
"Ephedra is a great bronchial dilator," McQuade-Crawford says. It helps asthma sufferers by opening the sinus passages and has an antihistamine effect which aids chronic and acute allergies. Ephedra also acts as a circulatory stimulant to blood pressure and heart function; it elevates blood pressure. Ephedra's main constituent is ephedrine, which increases adrenaline secretion in our bodies. The boost you get from ephedra stimulates certain glands, muscles and tissue functions, while it suppresses others.
"In the long term, ephedra's adrenaline overdrive can lead to chronic stress and even to degenerative disease," warns McQuade-Crawford. She notes this is important for people using ephedra for dietary weight loss or "pep pill" purposes because the effects of ephedra linger in the body long after the herb is gone. "Ephedra shouldn't be used with drugs for the heart or for the lungs and never with antidepressant drugs. It's not for use with the weak or the ill and when used long term, dosages should be conservative," McQuade-Crawford cautions.
Licorice
Licorice has been most recently researched as an antiviral and in the treatment of gastrointestinal ulceration, explains McQuade-Crawford. Its soothing, anti-inflammatory and relaxing actions help smooth muscles in the gastrointestinal tract on contact. "Licorice gets into a painful, contracted, tight digestive tract and coats the raw places, relaxes the clenched-up muscles and acts as a local anti-inflammatory," she says. Licorice also increases bile secretion. Licorice is indicated for any gastrointestinal ulcers, including mouth ulcers. The root is indicated for chronic coughs and bronchitis as a soothing decongestant. It's also indicated in small amounts to reduce sugar cravings.
The Chinese often use licorice to improve the taste and the effects of other herbs in complex formulas. Japanese research has shown licorice to decrease high testosterone levels in women with ovarian cysts and to increase their fertility. Large amounts of licorice or long-term use raises blood pressure in some people.
Bilberry
A strong antioxidant, bilberry benefits your circulatory system, eyes, heart and brain, and helps generate overall good health, says Schechter. Bilberry fruit contains a type of flavonoid called anthocyanosides, which are responsible for increasing flexibility of capillaries and increasing blood flow.
Research shows that standardized extract of bilberry can enlarge range of vision and improve sharpness of images, enhance ability to focus, and improve blurred vision, eyestrain and nearsightedness. Bilberry extract also helps strengthen coronary arteries and helps prevent atherosclerosis and venous insufficiency, which causes swollen ankles and feet. "Since adding bilberry to my own health program, I've noticed my muscles seem to recover slightly faster, I experience less muscular pain and my vision has improved from 20/100 to approximately 20/50," says Schechter.
Echinacea
Decades of research prove echinacea's value for aiding the immune system, Schechter explains. Studies have determined echinacea's ability to activate white blood cells and stimulate the regeneration of the cellular connective tissue and the epidermis. Schechter notes that echinacea's infection-fighting properties stem from its ability to neutralize a harmful enzyme involved in the infection process. Echinacea also increases two vital components of your immune system that consume and eliminate invading organisms and foreign particles.
German studies have shown echinacea extract contains proteins that help protect noninfected cells against viral infections, one reason why echinacea is regarded as an influenza preventor. Another German study found echinacea effective in allergy treatment because it helps prevent tissue inflammation due to harmful foreign toxins.
Milk Thistle
"I consider standardized milk thistle seed extract the most beneficial herbal product for liver detoxification, regeneration and protection, and, in general, one of the most universally necessary herbal products for the 1990s," says Schechter. He notes that the stress of toxins from chemical pollutants, pharmaceuticals, alcohol, tobacco smoke, drugs and different forms of radiation have cumulative side effects that need to be addressed.
More than 120 scientific studies have shown that milk thistle extract regenerates, regulates and strengthens liver functions. Because free radicals attack the liver, primarily the fat tissue in the liver, the antioxidant qualities of milk thistle are extremely beneficial. Milk thistle stimulates your body to produce superoxide dismutase, which is one of two primary antioxidants the body can manufacture.
Astragalus
Astragalus has been used as an immunity booster in China for nearly 4,000 years, according to Rob McCaleb, founder of the Herb Research Foundation in Boulder, Colo. Astragalus extracts can increase immune system efficiency by increasing immune activity. One study found that astragalus extracts could increase the impaired immune function of blood cells up to and sometimes beyond normal cell ability.
According to Planetary Herbology (Lotus Press) by Michael Tierra, N.D., astragalus helps strengthen digestion, raise metabolism, strengthen the immune system and promote wound healing. It can also treat chronic weakness of the lungs, shortness of breath, low energy, prolapse of internal organs, spontaneous sweating, chronic lesions and deficiency edema.
Ginseng
Ginseng is one of the most widely studied herbs, having been the subject of more than 3,000 scientific studies to investigate how ginseng helps improve a person's physical and/or mental performance, notes McCaleb. Studies have shown ginseng helps increase memory and learning by improving circulation. It's also been shown to reduce cholesterol and protect the liver from toxins. Ginseng, according to Tierra, is known to strengthen the lungs, nourish body fluids and calm the spirit. It may be used for shock, collapse and heart weakness, as well as for promoting longevity and increasing resistance to disease.
A Japanese study showed cancerous liver cells could be reverted to normal cells in a Petri dish culture when treated with Panax ginseng extract. Siberian ginseng has also been shown to stimulate the immune system.
Source of this document: http://www.all-natural.com/top-ten.html
Syllabus for Ph. D Admission Test in Biochemistry
Syllabus for Ph. D Admission Test in Biochemistry for the Academic Session 2009-2010 in the Department of Biochemistry, Faculty of Medicine, A. M. U., Aligarh:
1. Molecular Cell Biology: Constituents of human cell, their structure and function; properties of cell membrane and transport across membrane; cytoskeletons, epithelia and extracellular matrix; cell communication; programmed cell death; cell differentiation and cancer; p-53 gene; cancer present and future; stem cells and their possible role in therapy; neurobiology and neurochemistry; functions of muscle proteins; telomers and telomerase.
2. Blood and Biological Fluids: Hemoglobin, albumin and porins; serum proteins; chemistry of blood clotting; blood group; composition and diagnostic significance of cerebrospinal fluid and amniotic fluid; acute phase proteins (hsp).
3. Advanced Enzymology: Properties and catalytic behavior of enzymes; enzyme kinetics and regulation; mechanism of action of enzyme catalysis; therapeutic uses of enzymes; diagnostic significance of serum enzymes and isoenzymes; enzymatic markers in cardiac disorders; abzymes; allosteric enzymes.
4. Metabolism and its Integration and Basic Clinical Biochemistry: Metabolisms of carbohydrate, lipid, amino acids, proteins, heme and nucleic acids; inborn errors of metabolism; interrelationship and regulation of metabolic pathways; electron transport chain and oxidative phosphorylation. Metabolic and respiratory acidosis; analysis of analytes in blood, urine and cerebrospinal fluid; Liver function test (LFT); markers of myocardial infarction; fasting and post prandial blood sugar test; prostrate serum antigen (PSA) test; anti-DNA antibody test
5. Hormones: Role of hormones in the regulation of metabolism and mechanism of their action; consequences of hormone dysfunction; eicosanoids.
6. Advanced Molecular Biology: Structural aspects of genetic materials; replication and transcription; post transcriptional processing; translation; regulation of gene expression; DNA repair; human genome project and its implications; principles of cloning; recombinant DNA technology and its application; DNA vaccines; sequencing; screening of rDNA libraries; gene silencing; amplification and mutagenesis; restriction and molecular genetic maps; genomics and proteomics; antisense therapy.
7. Immunology: Immune response; cellular and protein components of immune system; antibody diversity and immunoglobulin genes; multiple myeloma; complement; monoclonal antibodies and their role in diagnostics and therapeutics; immunobiology of HIV and anti-HIV drugs; autoimmune disorders; mad cow disease; swine flue.
8. Vitamins, ions, trace elements: Metabolism of Ca, Pi, and trace elements (Se, Zn, Cu, Fe). Role of Na, K and Cl in homeostasis and related disorders; regulation of acid-base balance; biochemical functions of vitamins; vitamin toxicity; vitamin deficiency; vitamin-responsive inherited metabolic disorders; role of vitamins in free radical homeostasis.
9. Free radicals and anti-oxidants: Chemistry and pathology of free radicals and anti-oxidants.
10. Bioenergetics, Bioinformatics, Bioorganic and Biophysical Chemistry: Principles of bioenergetics, bioorganic and biophysical chemistry; spectroscopy and bioinformatics.
11. Techniques: Basic principles of sedimentation and analysis of sub-cellular fractions; HPLC; affinity chromatography; immunodiffusion; principles of electrophoresis; ultraviolet and visible light spectroscopy, circular dichroism spectroscopy; spectrofluorometry; band shift assay; array technology; DNA fingerprinting; ELISA; radioimmunoassay; immunoblotting; polymerase chain reaction; restriction mapping of DNA fragments; cell culture; nanomedicine technology; enzyme engineering.
12. Clinical and Experimental Estimations and Characterizations: estimation of LDL and HDL cholesterol in serum; enzymatic estimation of glucose; factors affecting enzyme activity; colorimetric estimation of bilirubin and urea in serum; UV characterization of DNA; flourometric properties of proteins; polyacrylamide gel electrophoresis (PAGE); affinity purification of IgG by Protein-A- Sepharose column.
13. Quality Control and Biostatistics: Quality Control and automation in clinical biochemistry; biostatistics and its application in research and clinical biochemistry; selection of statistical methods and their evaluation; sample size for designing experiments; standard error; standard deviation; student’s and paired ‘t’ tests; Chi-square test; fisher exact test; non-parametic tests of significance; multivariate analysis methods; one-way and two-way analysis of variance; multiple range tests.
1. Molecular Cell Biology: Constituents of human cell, their structure and function; properties of cell membrane and transport across membrane; cytoskeletons, epithelia and extracellular matrix; cell communication; programmed cell death; cell differentiation and cancer; p-53 gene; cancer present and future; stem cells and their possible role in therapy; neurobiology and neurochemistry; functions of muscle proteins; telomers and telomerase.
2. Blood and Biological Fluids: Hemoglobin, albumin and porins; serum proteins; chemistry of blood clotting; blood group; composition and diagnostic significance of cerebrospinal fluid and amniotic fluid; acute phase proteins (hsp).
3. Advanced Enzymology: Properties and catalytic behavior of enzymes; enzyme kinetics and regulation; mechanism of action of enzyme catalysis; therapeutic uses of enzymes; diagnostic significance of serum enzymes and isoenzymes; enzymatic markers in cardiac disorders; abzymes; allosteric enzymes.
4. Metabolism and its Integration and Basic Clinical Biochemistry: Metabolisms of carbohydrate, lipid, amino acids, proteins, heme and nucleic acids; inborn errors of metabolism; interrelationship and regulation of metabolic pathways; electron transport chain and oxidative phosphorylation. Metabolic and respiratory acidosis; analysis of analytes in blood, urine and cerebrospinal fluid; Liver function test (LFT); markers of myocardial infarction; fasting and post prandial blood sugar test; prostrate serum antigen (PSA) test; anti-DNA antibody test
5. Hormones: Role of hormones in the regulation of metabolism and mechanism of their action; consequences of hormone dysfunction; eicosanoids.
6. Advanced Molecular Biology: Structural aspects of genetic materials; replication and transcription; post transcriptional processing; translation; regulation of gene expression; DNA repair; human genome project and its implications; principles of cloning; recombinant DNA technology and its application; DNA vaccines; sequencing; screening of rDNA libraries; gene silencing; amplification and mutagenesis; restriction and molecular genetic maps; genomics and proteomics; antisense therapy.
7. Immunology: Immune response; cellular and protein components of immune system; antibody diversity and immunoglobulin genes; multiple myeloma; complement; monoclonal antibodies and their role in diagnostics and therapeutics; immunobiology of HIV and anti-HIV drugs; autoimmune disorders; mad cow disease; swine flue.
8. Vitamins, ions, trace elements: Metabolism of Ca, Pi, and trace elements (Se, Zn, Cu, Fe). Role of Na, K and Cl in homeostasis and related disorders; regulation of acid-base balance; biochemical functions of vitamins; vitamin toxicity; vitamin deficiency; vitamin-responsive inherited metabolic disorders; role of vitamins in free radical homeostasis.
9. Free radicals and anti-oxidants: Chemistry and pathology of free radicals and anti-oxidants.
10. Bioenergetics, Bioinformatics, Bioorganic and Biophysical Chemistry: Principles of bioenergetics, bioorganic and biophysical chemistry; spectroscopy and bioinformatics.
11. Techniques: Basic principles of sedimentation and analysis of sub-cellular fractions; HPLC; affinity chromatography; immunodiffusion; principles of electrophoresis; ultraviolet and visible light spectroscopy, circular dichroism spectroscopy; spectrofluorometry; band shift assay; array technology; DNA fingerprinting; ELISA; radioimmunoassay; immunoblotting; polymerase chain reaction; restriction mapping of DNA fragments; cell culture; nanomedicine technology; enzyme engineering.
12. Clinical and Experimental Estimations and Characterizations: estimation of LDL and HDL cholesterol in serum; enzymatic estimation of glucose; factors affecting enzyme activity; colorimetric estimation of bilirubin and urea in serum; UV characterization of DNA; flourometric properties of proteins; polyacrylamide gel electrophoresis (PAGE); affinity purification of IgG by Protein-A- Sepharose column.
13. Quality Control and Biostatistics: Quality Control and automation in clinical biochemistry; biostatistics and its application in research and clinical biochemistry; selection of statistical methods and their evaluation; sample size for designing experiments; standard error; standard deviation; student’s and paired ‘t’ tests; Chi-square test; fisher exact test; non-parametic tests of significance; multivariate analysis methods; one-way and two-way analysis of variance; multiple range tests.
Onions are Beneficial for Your Health
Onions are Beneficial for Your Health
The following excellant article by Winston Craig, MPH, PhD, RD, Professor of Nutrition, Andrews University, MI, USA is highly informative about the benefits of onion to mankind. For the benefit of mankind, it is being reproduced here.
What would life be like without onions? The onion has been used as an ingredient in various dishes for thousands of years by many cultures around the world. World onion production is steadily increasing so that onion is now the second most important horticultural crop after tomatoes.
There are many different varieties of onion, red, yellow, white, and green, each with their own unique flavor, from very strong to mildly sweet. Onions can be eaten raw, cooked, fried, dried or roasted. They are commonly used to flavor dips, salads, soups, spreads, stir-fry and other dishes.
Onions (Allium cepa) belong to the lily family, the same family as garlic, leeks, chives, scallions and shallots.There are over 600 species of Allium, distributed all over Europe, North America, Northern Africa and Asia. The plants can be used as ornamentals, vegetables, spices, or as medicine. There are over 120 different documented uses of the Alliums.
Onion and other Allium vegetables are characterized by their rich content of thiosulfinates, sulfides, sulfoxides, and other odoriferous sulfur compounds. The cysteine sulfoxides are primarily responsible for the onion flavor and produce the eye-irritating compounds that induce lacrimation. The thiosulfinates exhibit antimicrobial properties. Onion is effective against many bacteria including Bacillus subtilis, Salmonella, and E. coli. Onion is not as potent as garlic since the sulfur compounds in onion are only about one-quarter the level found in garlic.
The Value of Onions
Onions have a variety of medicinal effects. Early American settlers used wild onions to treat colds, coughs, and asthma, and to repel insects. In Chinese medicine, onions have been used to treat angina, coughs, bacterial infections, and breathing problems.
The World Health Organization (WHO) supports the use of onions for the treatment of poor appetite and to prevent atherosclerosis. In addition, onion extracts are recognized by WHO for providing relief in the treatment of coughs and colds, asthma and bronchitis. Onions are known to decrease bronchial spasms. An onion extract was found to decrease allergy-induced bronchial constriction in asthma patients.
Onions are a very rich source of fructo-oligosaccharides. These oligomers stimulate the growth of healthy bifidobacteria and suppress the growth of potentially harmful bacteria in the colon. In addition, they can reduce the risk of tumors developing in the colon.
Cardiovascular Help
Onions contain a number of sulfides similar to those found in garlic which may lower blood lipids and blood pressure. In India, communities that never consumed onions or garlic had blood cholesterol and triglyceride levels substantially higher, and blood clotting times shorter, than the communities that ate liberal amounts of garlic and onions. Onions are a rich source of flavonoids, substances known to provide protection against cardiovascular disease. Onions are also natural anticlotting agents since they possess substances with fibrinolytic activity and can suppress platelet-clumping. The anticlotting effect of onions closely correlates with their sulfur content.
Cancer Prevention
Onion extracts, rich in a variety of sulfides, provide some protection against tumor growth. In central Georgia where Vidalia onions are grown, mortality rates from stomach cancer are about one-half the average level for the United States. Studies in Greece have shown a high consumption of onions, garlic and other allium herbs to be protective against stomach cancer.
Chinese with the highest intake of onions, garlic, and other Allium vegetables have a risk of stomach cancer 40 percent less than those with the lowest intake. Elderly Dutch men and women with the highest onion consumption (at least one-half onion/day) had one-half the level of stomach cancer compared with those consuming no onions at all.
Western Yellow, New York Bold, and Northern Red onions have the richest concentration of flavonoids and phenolics, providing them with the greatest antioxidant and anti-proliferative activity of 10 onions tested. The mild-tasting Western White and Vidalia onions had the lowest antioxidant content and lowest anti-proliferative activity. The consumer trend to increasingly purchase the less pungent, milder onion varieties may not be the best, since the onions with a stronger flavor and higher astringency appear to have superior health-promoting properties.
Use and Safety
Onions have a universal appeal. They are safely consumed by most people. However, consuming large quantities of onions can lead to stomach distress and gastrointestinal irritation that may result in nausea and diarrhea. There are no known interactions with drugs except that they can potentiate the action of anticoagulants.
Conclusion
Onions, and other Allium species, are highly valued herbs possessing culinary and medicinal value. Some of their beneficial properties are seen after long-term usage. Onion may be a useful herb for the prevention of cardiovascular disease, especially since they diminish the risk of blood clots. Onion also protects against stomach and other cancers, as well as protecting against certain infections. Onion can improve lung function, especially in asthmatics. The more pungent varieties of onion appear to possess the greatest concentration of health-promoting phytochemicals.
Author: Winston Craig, MPH, PhD, RD.
Copyright © 2003 - 2008 Winston Craig, PhD, MPH, RD, Professor of Nutrition, Andrews University, MI, USA.
The following excellant article by Winston Craig, MPH, PhD, RD, Professor of Nutrition, Andrews University, MI, USA is highly informative about the benefits of onion to mankind. For the benefit of mankind, it is being reproduced here.
What would life be like without onions? The onion has been used as an ingredient in various dishes for thousands of years by many cultures around the world. World onion production is steadily increasing so that onion is now the second most important horticultural crop after tomatoes.
There are many different varieties of onion, red, yellow, white, and green, each with their own unique flavor, from very strong to mildly sweet. Onions can be eaten raw, cooked, fried, dried or roasted. They are commonly used to flavor dips, salads, soups, spreads, stir-fry and other dishes.
Onions (Allium cepa) belong to the lily family, the same family as garlic, leeks, chives, scallions and shallots.There are over 600 species of Allium, distributed all over Europe, North America, Northern Africa and Asia. The plants can be used as ornamentals, vegetables, spices, or as medicine. There are over 120 different documented uses of the Alliums.
Onion and other Allium vegetables are characterized by their rich content of thiosulfinates, sulfides, sulfoxides, and other odoriferous sulfur compounds. The cysteine sulfoxides are primarily responsible for the onion flavor and produce the eye-irritating compounds that induce lacrimation. The thiosulfinates exhibit antimicrobial properties. Onion is effective against many bacteria including Bacillus subtilis, Salmonella, and E. coli. Onion is not as potent as garlic since the sulfur compounds in onion are only about one-quarter the level found in garlic.
The Value of Onions
Onions have a variety of medicinal effects. Early American settlers used wild onions to treat colds, coughs, and asthma, and to repel insects. In Chinese medicine, onions have been used to treat angina, coughs, bacterial infections, and breathing problems.
The World Health Organization (WHO) supports the use of onions for the treatment of poor appetite and to prevent atherosclerosis. In addition, onion extracts are recognized by WHO for providing relief in the treatment of coughs and colds, asthma and bronchitis. Onions are known to decrease bronchial spasms. An onion extract was found to decrease allergy-induced bronchial constriction in asthma patients.
Onions are a very rich source of fructo-oligosaccharides. These oligomers stimulate the growth of healthy bifidobacteria and suppress the growth of potentially harmful bacteria in the colon. In addition, they can reduce the risk of tumors developing in the colon.
Cardiovascular Help
Onions contain a number of sulfides similar to those found in garlic which may lower blood lipids and blood pressure. In India, communities that never consumed onions or garlic had blood cholesterol and triglyceride levels substantially higher, and blood clotting times shorter, than the communities that ate liberal amounts of garlic and onions. Onions are a rich source of flavonoids, substances known to provide protection against cardiovascular disease. Onions are also natural anticlotting agents since they possess substances with fibrinolytic activity and can suppress platelet-clumping. The anticlotting effect of onions closely correlates with their sulfur content.
Cancer Prevention
Onion extracts, rich in a variety of sulfides, provide some protection against tumor growth. In central Georgia where Vidalia onions are grown, mortality rates from stomach cancer are about one-half the average level for the United States. Studies in Greece have shown a high consumption of onions, garlic and other allium herbs to be protective against stomach cancer.
Chinese with the highest intake of onions, garlic, and other Allium vegetables have a risk of stomach cancer 40 percent less than those with the lowest intake. Elderly Dutch men and women with the highest onion consumption (at least one-half onion/day) had one-half the level of stomach cancer compared with those consuming no onions at all.
Western Yellow, New York Bold, and Northern Red onions have the richest concentration of flavonoids and phenolics, providing them with the greatest antioxidant and anti-proliferative activity of 10 onions tested. The mild-tasting Western White and Vidalia onions had the lowest antioxidant content and lowest anti-proliferative activity. The consumer trend to increasingly purchase the less pungent, milder onion varieties may not be the best, since the onions with a stronger flavor and higher astringency appear to have superior health-promoting properties.
Use and Safety
Onions have a universal appeal. They are safely consumed by most people. However, consuming large quantities of onions can lead to stomach distress and gastrointestinal irritation that may result in nausea and diarrhea. There are no known interactions with drugs except that they can potentiate the action of anticoagulants.
Conclusion
Onions, and other Allium species, are highly valued herbs possessing culinary and medicinal value. Some of their beneficial properties are seen after long-term usage. Onion may be a useful herb for the prevention of cardiovascular disease, especially since they diminish the risk of blood clots. Onion also protects against stomach and other cancers, as well as protecting against certain infections. Onion can improve lung function, especially in asthmatics. The more pungent varieties of onion appear to possess the greatest concentration of health-promoting phytochemicals.
Author: Winston Craig, MPH, PhD, RD.
Copyright © 2003 - 2008 Winston Craig, PhD, MPH, RD, Professor of Nutrition, Andrews University, MI, USA.
Neem: Mode of Action of Compounds Present in Extracts and Formulations of Azadirachta indica Seeds and Their Efficacy to Pests of Ornamental Plants an
Neem: Mode of Action of Compounds Present in Extracts and Formulations of Azadirachta indica Seeds and Their Efficacy to Pests of Ornamental Plants and to Non-Target Species
D. Casey Sclar
Colorado State University
Fort Collins, Colorado 80523
Summary: Overview of growth habits and culture of Azadirachta indica.
Commercial and experimental sources of Neem formulations. The mode of
action of azadirachtin and other principal chemical compounds present in
Neem extracts. The efficacy of various Neem formulations to arthropod
pests of ornamental plants and to non-target organisms. A discussion of
future directions in Neem research is presented.
Key Words:Neem, Azadirachtin, Antifeedant, Insect Growth Regulator,
Ornamental Plants, Botanical Insecticides.
I. Introduction:
In recent years, several reviews have been published which outline
the use of the Neem tree, Azadirachta indica (Meliaceae) as a botanical
insecticide (Jacobson, 1989; Koul et al. 1990; Schmutterer, 1990;
Ascher, 1993). The mode of action of azadirachtin, the principal
insecticidal constituent of Neem oil has only recently been elucidated
(Mordue & Blackwell, 1993). Little attention has been paid to recent
experiments involving Neem's use as an insecticide for arthropod pests
of ornamental plants (Cranshaw et al., 1993). This paper was written to
accomplish three functions: First, to acquaint the reader with the Neem
tree and sources of Neem oil available commercially and experimentally.
Second, to outline the mode of action of azadirachtin and the other
compounds present in Neem oil. Finally, a report on experiments
involving the use of Neem to control ornamental plant pests and efficacy
to non-target organisms is presented.
II. The Neem Tree:
The Neem tree, Azadirachta indica (Meliaceae) is native to
Southeast Asia and grows in many countries throughout the world
(Schmutterer, 1990; Ascher, 1993). It is closely related to the
Chinaberry tree, Melia azedarach (Meliaceae) (also called Persian
Lilac). M. azedarach contains several biologically active compounds.
Although more widely distributed than A. indica because of its hardier
nature and more pleasing appearance, the use of M. azedarach as a
natural insecticide is limited because it contains tetranitroterpenoid
compounds known as meliatoxins that are highly toxic to mammals (Ascher,
1993).
A. indica propagates readily from cuttings, stumps, tissue culture
or seed. Seed propagation in nurseries followed by direct planting
into the field is the accepted method to produce plantation stands
quickly and efficiently (Jacobson, 1989). It is widely used as a shade
tree in many areas (as is M. azedarach) because it tolerates a wide
variety of field conditions (Koul, 1990; Schmutterer, 1990). The tree
tolerates heat up to 50oC, and poor, shallow, even saline soils (Koul,
1990; Schmutterer, 1990; Ascher, 1993). A. Indica grows rapidly; 4-7
meters in its first five years of growth and 5-11m for the following
five years. It will bear fruit within three years and reach a maximum
fruiting yield of 50kg seed/year ten years after planting
(Jacobson,1989; Koul, 1990; Ascher, 1993). A. indica is sensitive to
injury at temperatures around 0oC, which limits its distribution in
temperate regions of the world (Jacobson, 1989; Koul, 1990; Ascher,
1993).
The Neem tree has many medicinal uses. Notable among these are its
use as an antiseptic and diuretic. It has been used to cure many
illnesses from diabetes to syphilis, and is widely relied upon by
herbalists in its native habitat (Jacobson, 1989; Koul, 1990). The use
of A. indica as a source of natural insecticide was discovered
approximately 30 years ago (Ascher, 1993).
III. Sources of Neem:
III.1 Within Plant Distribution
Seeds of the Neem tree contain the highest concentration of
azadirachtin and all other biologically active chemical compounds
present in A. indica. (Jacobson, 1989; Koul, 1990; Schmutterer, 1990).
Other tissues of A. indica known to contain these compounds at lower
levels are the bark, leaves and heartwood (Ascher, 1993). Because they
contain the highest concentrations of biologically active compounds,
most experimental and commercial preparations of Neem are seed extracts
(Jacobson, 1989). Aqueous, methanolic and ethanolic extracts of Neem
seeds show biological activity in the laboratory and the field,
although at a varying extent to different target organisms (Ascher,
1993).
III.2 Commercial and Experimental Sources of Neem
The first commercial Neem insecticide, Margosan-O_, was registered
by the EPA for non-crop use in the United States in July, 1985
(Jacobson, 1989). Since that time, the EPA has exempted Margosan-O_
from food crop tolerances and several other commercial Neem insecticides
have been developed worldwide (Ascher, 1993). Table 1 lists current
commercial and experimental suppliers of Neem extracts and formulations.
Table 1: Commercial and Experimental Sources of Neem Within the United
States (Adapted from Larson, 1993; Mordue & Blackwell, 1993)
Company Name and Address Trade Name Formulation (a)
AgriDyne Technologies, Inc. Turplex (formerly Azatin)C
417 Wakara Way
Salt Lake City, UT 84108
Gharda Chemicals Neemguard C
Bombay, India
Grace/Sierra, Inc. Margosan-O C
Iron Run Industrial Park
570 Grant Way
P.O. Box 789
Fogelsville, PA 18051
ITC Ltd. Wellgro, RD- Repelin C
Andhra Pradesh, India
Ringer Corp. Bioneem, Neemesis C
9959 Valley View Road (former Safer Ltd. products
Eden Prairie, MN 55344 consolidated here)
Rohm & Haas Co. RH - 9999 E
Independence Mall West
Philadelphia, PA 19105
Trifolio M GmBH Neemazal C
D-6335
Lahnau 2, Germany
USDA-ARS N/A E
National Center for Agricultural
Utilization Research
Peoria, IL 61601
Valent USA Corp. AD 1000 E
1333 N. California Boulevard #600
P.O. Box 8025
Walnut Creek, CA 94526-8025
West Coast Herbochem Neemark C
Bombay, India
a Key: C = Commercial, E = Experimental
Experimental sources of Neem remain cryptic. Within the United
States of America, only the USDA-ARS is a consistent supplier of raw,
unprocessed Neem seeds. Individual research laboratories may have
sources not known by the author.
IV. Modes of Action of Neem Oil Compounds:
IV.1 Overview
All biologically active Neem compounds are suspected to be derived
from one parent compound, the tetracyclic triterpenoid tirucallol (Fig.
1). All other products formed are considered successive rearrangement
and oxidation products of tirucallol (Ascher, 1993). It is generally
accepted that the tetranotriterpenoid (also called limonoid) compound
azadirachtin (Fig. 1) is responsible for the majority of biological
effects observed in organisms exposed to Neem compounds (Isman, 1990;
Mordue & Blackwell, 1993; Verkerk & Wright, 1993). However, 25
different biologically active compounds have been isolated from Neem
seeds (Lee et al., 1991). Other compounds present in Neem oil are
responsible for some of the biological activity observed (See - IV.4:
Other Effects of Neem).
Figure 1. The structures of tirucallol and azadirachtin
(Ascher,1993)
Within the azadirachtin molecule, the decalin fragment is
responsible for the insect growth regulation and development effects
observed, while the hydroxy furan fragment causes the antifeedant
effects more widely observed among target species (Fig. 2)(Aldhous,
1992). The IGR and antifeedant effects of azadirachtin are independent
of each other, but both remain relative to concentration (Koul & Isman,
1991).
Figure 2. The decalin and hydroxy furan fragments of azadirachtin
(Aldhous,
1992)
IV.2 Antifeedant Effects of Azadirachtin
The antifeedant effects of azadirachtin are well known (for reviews
see Jacobson, 1989; Schmutterer, 1990; Ascher, 1993; Mordue and
Blackwell, 1993). Both primary and secondary antifeedant effects have
been observed in the case of azadirachtin (Ascher,1993). Primary
effects include the process of chemoreception by the organism (e.g.
sensory organs on mouthparts which stimulate the organism to begin
feeding) whereas secondary processes are effects such as gut motility
disorders due to topical application only (Schmutterer, 1990;
Ascher,1993). Inhibition of feeding behavior by azadirachtin results
from blockage of input receptors for phagostimulants or by the
stimulation of deterrent receptor cells or both (Mordue & Blackwell,
1993). In a recent study by Yoshida and Toscano (1994), the relative
consumption rate of Heliothis virescens larvae treated with azadirachtin
was 25% of the control, attributing to the lowest assimilation
efficiency of all natural insecticides tested. In another study, larvae
of Heliothis virescens consumed less food, gained less weight, and were
less efficient at converting ingested and digested food into biomass
(Barnby & Klocke, 1987). Sensitivity between species to the
antifeedant effects of azadirachtin are profound. Order Lepidoptera
appear most sensitive to azadirachtin's antifeedant effects, with
Coleoptera, Hemiptera and Homoptera being less sensitive (Mordue &
Blackwell, 1993).
IV.3 Insect Growth Regulatory Effects of Azadirachtin
The insect growth regulatory effects of azadirachtin (in contrast
to its antifeedant effects) are remarkably similar among species (Mordue
& Blackwell, 1993). Various developmental, post-embryonic, reproductive
and growth inhibitory affects have been observed, causing malformation
and mortality in a dose-dependent manner (Ascher, 1993).
Schmutterer (1990) suggested that azadirachtin modifies the
programs of insects by influencing hormonal systems, especially that of
ecdysone. The effects of azadirachtin are both dose and time
dependent, prevent both ecdysis and apolysis, and can cause death before
or during molting, possibly inducing "permanent" larvae (Mordue &
Blackwell, 1993). Exogenous application of growth hormones did not
deter the effects of azadirachtin, leading researchers to suggest that
the most probable site of action of azadirachtin is at the site of
synthesis and release of Prothoracicotropic hormone (PTTH) (Koul and
Isman, 1991). The main action of azadirachtin appears to be at the
release sites of PTTH from the corpora cardiaca. Azadirachtin appears
to block the release of neurosecretory material from the corpora
cardiaca resulting in a reduced turnover rate. This affects the rate of
synthesis of PTTH by brain neurosecretory cells (Barnby & Klocke, 1990;
Mordue & Blackwell, 1993). Marco et al. (1990) stated that azadirachtin
caused a significant depletion of immunoreactive ecdysteroids in
Tenebrio molitor pupae. T. molitor has no PTTH glands and yet is still
sensitive to the ecdysteroid antagonistic effect exhibited by exposure
to azadirachtin. A possible explanation for this phenomenon could
involve epidermal cells or oenocytes being affected as both are
suggested as alternative sites of ecdysteriod production. It should be
noted that all these effects are working in conjunction with blockages
in JH (juvenile hormone) and allotropin titers, collectively resulting
in both molting and reproductive aberrations. It is assumed that
azadirachtin has direct effects on a variety of tissues and organs. This
suggests either a number of different modes of action or a specific
toxic lesion to all cells which manifests itself more obviously in some
cells than others (Mordue & Blackwell, 1993). All insect growth
regulatory effects of azadirachtin are suggested by Schmutterer (1990)
to be indirectly influenced by temperature, with greater activity seen
at higher temperatures.
IV.4 Other Effects of Neem (Unconventional Effects)
It has been noted that the presence of azadirachtin alone is not as
toxic as all Neem oil components present together (Verkerk & Wright,
1993). Other compounds present in Neem seed extracts besides
azadirachtin exhibit biological activity in myriad ways (Ascher, 1993).
Blaney et al. (1990) found that salinnin and nimbin, two other compounds
present in Neem seed extracts, exhibit an entirely different mode of
action than azadirachtin. Effects which may be exhibited by one or more
compounds present in Neem seed extracts include: oviposition repellency,
egg sterility, longevity, fitness and inhibition of chitin biosynthesis
(Ascher, 1993).
Use of a commercial formulation of Neem (RD-Repelin) successfully
deterred aphids attempting to land, probe or oviposit (Hunter and
Ullman, 1992). Lowery & Isman (1993) suggest that this deterrence
results from a variety of compounds working in concert with one another,
producing different behavioral responses which vary in magnitude between
species. Schmutterer (1990) reported reduced fecundity and longevity in
aphids treated with Neem seed extract. Treatment with Neem oil resulted
in a reduction of eggs produced and increased incubation time for eggs
of the spider mite Tetranychus urticae (Dimetry et al., 1993). Neem
inhibited adult eclosion and reproductive potential in Liriomyza
trifolii, as well as longevity of adults surviving treatment as eggs or
larvae (Parkman and Pienkowski, 1990). A reduction in transmission of
aphid-borne viruses in some species has also been observed (Hunter &
Ullman, 1992; Mordue & Blackwell, 1993).
It is suggested that Neem compounds which are present in solid form
in or upon leaf surfaces are responsible for these effects. Evidence
supporting this hypothesis is the study of Pathak & Krishna (1991) in
which Eucalyptus oil volatiles adversely affected growth and
reproduction of Corcyra cephalonica whereas exposure to Neem oil
volatiles had no effect.
Other effects of Neem are more behavioral in nature. Saxena et al.
(1993) reported that Neem disrupted mating signals in Nilaparvata lugens
(Homoptera: Delphacidae). Some insects failed to produce calls, while
others emitted unrecognizable calls.
V. Use of Neem Oil for Ornamental Plant Pest Control:
V.1 Use of Neem to Control Greenhouse Ornamental Plant Pests
Larew (1990) reviewed the use of Neem against pests of greenhouse
crops. The resistance of greenhouse pests to many insecticides and the
introduction of new pests (e.g. the Sweetpotato Whitefly - Bemesia
tabaci) to the greenhouse environment continue to complicate the
production of ornamental greenhouse crops. Although Schmutterer (1990)
suggested that the use of Neem may not be suitable for crops with high
quality demands, many successes have been reported using Neem
formulations to control pests on greenhouse ornamental plants.
Chrysanthemum Leafminer (Liriomyza trifolii) is an extremely
devastating pest of indoor greenhouses. Using Neem extracts, greenhouse
population levels of this pest were significantly reduced (Parkman and
Pienkowski, 1990). Leafminer infestations occur primarily by the
introduction of infested cuttings into the greenhouse. Sanderson et al.
(1989) observed decreased larval population and adult emergence level
after drenching boxed cuttings with Neem oil before shipping. Ascher et
al. (1992) used the commercial Neem formulation Azatin (now called
Turplex) to successfully reduce nymphal populations of Frankliniella
occidentalis, a thrips species difficult to control with conventional
insecticides.
Whiteflies represent perhaps the biggest challenge to growers of
greenhouse ornamental crops. Lindquist et al. (1990) reported the
efficacy of Neem against both susceptible and binfenthrin-resistant
populations of the Greenhouse Whitefly (Trialeurodes vaporarium). Price
and Schuster (1991) conducted field trials using Neem and various other
synthetic insecticides to control populations of Bemesia tabaci on
Poinsettia plants. Their data show that although Neem was slower to
display an initial effect, it ultimately yielded a level of control
comparable to that of many synthetic insecticides. This effect was
present without the phytotoxicity to leaves and bracts commonly
associated with the use of synthetic insecticides on Poinsettias.
V.2 Use of Neem to Control Pests of Landscape Ornamental Plants
Not since the review in Jacobson (1989) has the use of Neem for
control of landscape plant pests been addressed. During that time, new
developments have surfaced in the use of Neem for this purpose.
Schmutterer (1990) noted antifeedant effects of azadirachtin to Japanese
Beetle (Popillia japonica), a major pest of landscape plants in North
America. A reduction in field populations of aphids of various species
was reported by Lowery et al. (1993) at a level of control similar to
that of pyrethrum, another botanical insecticide. In a subsequent
paper, Lowery & Isman (1993) state that the settling and probing
behavior of the resistant aphid species Myzus persicae was not deterred
by Neem compounds, although the behavior of two other aphid species
(Sitobion avenae and Rhopalosiphum padi) was successfully its use.
Stark (1992) suggested that Neem would be useful as part of a turfgrass
IPM program. Recently, Cranshaw et al. (1993) reported the efficacy of
several commercial formulations of Neem against eggs and larvae of the
Elm Leaf Beetle (Xanthogaleruca luteola) in laboratory and field trials.
VI. The Efficacy of Neem to Non-Target Organisms:
Neem's efficacy to non-target and beneficial organisms has been
documented in previous and recent literature (Jacobson, 1989;
Schmutterer, 1990; Ascher, 1993; Mordue & Blackwell, 1993). Table 2
summarizes the effects of various formulations of Neem to several
different organisms. Because the amount of azadirachtin and other
compounds present in Neem oil is often not quantified by researchers,
the long-assumed benign effects of Neem to non-target organisms listed
below may be questionable (Stark, 1992). For this reason, data
presented in Table 2 is of qualitative nature only. As stated
previously, Neem is widely utilized in the tropics by humans for
medicinal purposes, and is assumed to have no detrimental effects to
humans with the exception of one trial in which an aflatoxin-
contaminated carrying agent is suspected to have been present (Jacobson,
1989; Schmutterer, 1990).
VII. Conclusion: Future Directions in Neem Research:
In the future, researchers will continue to elucidate the modes of
action of azadirachtin at a cellular level, and investigate the
mechanisms of biological activity exhibited by the other chemical
components found in Neem oil (Mordue & Blackwell, 1993). Other areas
which may be focused upon are insect resistance to azadirachtin and Neem
oil, the possible use of Neem as a systemic chemical and the stability
of Neem compounds in the field . Neem offers promise in the fight
against pesticide resistance, because of the diverse mode(s) of action
of azadirachtin and other Neem-associated compounds (Jacobson, 1989;
Ascher, 1993). It was recently hypothesized that the type of host plant
involved in a given situation may effect Neem's efficacy against a
particular pest (Lowery et al., 1993). What impact this will have in
future experiments remains to be seen.
Table 2: A selective summary of the effects of compounds present
in Neem extracts against non-target organisms and beneficial insects.
Organism Effect Level Reference Comments
Predaceous Spiders:
Lycosa pseudoannulata NE (Schmutterer, 1990)
Chiracanthium mildei NE (Schmutterer, 1990)
Predaceous Mites:
Phytoseiulus persimilis NE (Schmutterer, 1990) Some mortality
observed
but significantly
less than
that of target
organism
Oribatid Mites: OA (Stark, 1992)
Predaceous Coccinellids:
Delphastus pusillus NE (Schmutterer, 1990) No effect when
either
(Hoelmer et al., 1990) plant or prey
eggs treated
Predaceous Hemiptera:
Perillys bioculatus OA (Mordue & Blackwell,
1993)
Honeybees:
Apis mellifera NE (Schmutterer, 1990) No effect in
colonies of
> 200 individuals
Hymenopterous Parasitoids:
Aleurodiphilus sp. OA (Price & Schuster,
1991)
Apanteles glomeratus NE (Schmutterer, 1992) Below 40ppm/ AZ
Aphidius cerasicola NE (Schmutterer, 1990)
Cotesia congregata OA (Mordue & Blackwell,1993)
Dieratiella rapae NE (Schmutterer, 1990)
Encarsia sp. OA (Price & Schuster, 1991)
Telenomous remous OA (Schmutterer, 1990) Reduced longevity
Collembola: NE (Stark, 1992)
Rainbow Trout OA (Jacobson, 1989)
(Schmutterer, 1990)
a Key: NE = No biological effect observed, OA = Organism affected by
treatment
Recent reviews validated the theory that Neem has systemic action
(Ascher, 1993; Mordue & Blackwell, 1993). Xie et al. (1991) used soil
drenches of Neem to control laboratory populations of the Western Corn
Rootworm, Diabrotica virgifera virgifera and noted persistent effects
to adults feeding on plants as well as to the subterranean grubs and
pupae treated.
A foliar spray application of most commercial Neem formulations
persists 5-7 days under field conditions (possibly longer due to some
systemic effects) (Schmutterer, 1990). Even though breakdown of
azadirachtin occurs in UV light, its metabolites may still have
bioactivity (Ascher, 1993). Dihydroazadirachtin, a compound obtained by
hydrogenation of the C-22, 23 double bond of the hydroxy furan fragment
of azadirachtin, currently shows promise as a more stable compound for
better field persistence (Mordue & Blackwell, 1993). In previous
studies, hydrogenation of the hydroxy furan fragment resulted in no
decrease in bioactivity of the molecule (Blaney et al., 1990).
The types of substitutions made to the azadirachtin molecule are
important in the efficacy of the compound to target organisms. Several
different bioactive forms of the azadirachtin molecule exist.
Substitutions at some positions on the molecule will increase efficacy
to a particular target organism whereas other substitutions will result
in decreased efficacy to the same species (Simmonds et al., 1990).
Pure chemical synthesis of the azadirachtin molecule was once thought to
be impractical because of the difficult steps involved and the size of
the molecule. However, the group of Ley and Simmonds at Imperial
College in London have recently reported the success at the synthesis of
both the decalin fragment and the hydroxy furan fragment, with only the
linkage of the two fragments remaining to form the entire molecule of
azadirachtin in vitro (Aldhous, 1992). Future chemical synthesis of the
azadirachtin molecule and chemical mimics hold promise for the discovery
of safe pesticides with faster knockdown activity. This synthesis may
yield the ability to create and test each chemical component of Neem oil
in an isolated environment. Experiments of this nature would allow
researchers to continue to unravel the mystery surrounding the activity
of Neem compounds. Research of this type enhances the existing
knowledge of how Neem controls insects and mites, allowing better use of
this product by consumers, growers, farmers, and researchers.
VIII.Literature Cited
Aldhous, P. (1992) Neem chemical: the pieces fall into place. Science
258: 893.
Ascher, K. R. S., Klein, M. & J. Meisner (1992) Azatin, a Neem
formulation, acts on nymphs of the western flower thrips.
Phytoparasitica 20: 305-306.
Ascher, K. R. S. (1993) Nonconventional insecticidal effects of
pesticides available from the Neem tree, Azadirachta indica. Arch.
Insect Biochem. Physiol. 22: 433-449.
Barnby, M. A. & J. A. Klocke (1987) Effects of azadirachtin on the
nutrition and development of the Tobacco Budworm, Heliothis virescens
(Fabr) (Lepidoptera: Noctuidae). J. Insect Physiol. 33: 69-75.
Blaney, W. M., Simmonds, M. S. J., Ley, S. V., Anderson, J. C. & P.L.
Toogood (1990) Antifeedant effects of azadirachtin and structurally
related compounds on lepidopterous larvae. Entomol. Exp. Appl. 55:
149-160.
Cranshaw, W. S., Zimmerman, R. J., Randolph, T. & C. Sclar (1994)
Toxicity of Neem derived insecticides and horticultural oils to various
life stages of the Elm Leaf Beetle, Xanthogaleruca luteola (Muller)
(Coleoptera: Chrysomelidae). J. Arboric. (Submitted Manuscript)
Dimetry, N. Z., Amer, S. A. A. & A. S. Reda (1993) Biological activity
of two Neem seed kernel extracts against the two-spotted spider mite
Tetranychus urticae Koch. J. Appl. Entomol. (Zeitschrift fur Angewandte
Entomologie). 113: 79-87.
Hoelmer, K. A., Osborne, L. S. & R. K. Yokomi (1990) Effects of Neem
extracts on beneficial insects in greenhouse culture. In Proc. USDA
Neem Workshop, USDA-ARS 86 p. 100-105.
Hunter, W. B. & D. E. Ullman (1992) Effects of the Neem product, Rd-
Repelin, on settling behavior and transmission of Zucchini Yellow Mosaic
Virus by the Pea Aphid, Acyrthosiphon pisium (Harris) (Homoptera:
Aphididae). Ann. Appl. Biol. 120: 9-15.
Isman, M. B., Koul, O., Luczynski, A. & J. Kaminski (1990) Insecticidal
and antifeedant bioactivities of Neem oils and their relationship to
azadirachtin content. J. Argi. Food Chem. 38: 1406-1411.
Jacobson, M., ed. (1989) 1988 Focus on phytochemical pesticides,
Volume 1: The Neem Tree. CRC Press, Boca Raton, FL. 178pp.
Koul, O., Isman, M. B. & C. M. Ketkar (1990) Properties and uses of
Neem, Azadirachta indica. Can. J. Bot. 68: 1-11.
Koul, O. & M. B. Isman (1991) Effects of azadirachtin on the dietary
utilization and development of the Variegated Cutworm Peridroma saucia.
J. Insect Phys. 37: 591-598.
Larew, H. G. (1990) Activity of Neem seed oil against greenhouse pests.
In Proc. USDA Neem Workshop, USDA-ARS 86 p.128-131.
Larson, L. L. (1993) Materials under trial: information on composition,
formulation and suppliers. Insecticide and Acaricide Tests 18:375-390.
Lee, S. M., Klocke, J. A., Barnby, M. A., Yamasaki, R. B. & M. F.
Balandrin (1991) Insecticidal constituents of Azadirachta indica and
Melia azedarach (Meliaceae). ACS Symp. Series 449: 293-304.
Lindquist, R. K., Adams, A. J., Hall, F. R. & I. H. H. Adams (1990)
Laboratory and greenhouse evaluations of Margosan-O against bifenthrin-
resistant and -susceptible greenhouse whiteflies, Trialeurodes
vaporarium (Homoptera: Aleyrodidae). In Proc. USDA Neem Workshop, USDA-
ARS 86 p. 91-99.
Lowery, D. T., Isman, M. B. & N. L. Brard (1993) Laboratory and field
evaluations of Neem for the control of Aphids (Homoptera: Aphididae).
J. Econ. Ent. 86: 864-870.
Lowery, D. T. & M. B. Isman (1993) Antifeedant activity of extracts
from Neem, Azadirachta indica, to Strawberry aphid, Chaetosiphon
fragaefolii. J. Chem. Ecol. 19: 1761-1773.
Marco, M. P., Pascual, N., Bell_s, X., Camps, F. & A. Messeguer (1990)
Ecdysteroid depletion by azadirachtin in Tenebrio molitor pupae.
Pesticide Biochem. Physiol. 38: 60-65.
Mordue, A. J. & A. Blackwell (1993) Azadirachtin: an update. J.
Insect Phys. 39: 903-924.
Parkman, P. & R. L. Pienkowski (1990) Sublethal effects of Neem seed
extract on adults of Liriomyza trifolii (Diptera: Agromyzidae). J.
Econ. Ent. 83: 1246-1249.
Pathak, P.P. & S. S. Krishna (1991) Postembryonic development and
reproduction in Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae)
on exposure to Eucalyptus and Neem seed oil volatiles. J. Chem. Ecol.
17: 2553-2558.
Price, J. F. & D. J. Schuster (1991) Effects of natural and synthetic
insecticides on Sweetpotato Whitefly Bemesia tabaci (Homoptera:
Aleyrodidae) and its hymenopterous parasitoids. Florida Ent. 74: 60-
68.
Sanderson, K. C., Oetting, R. D. & D. A. Smith (1989) In-transit Neem
insecticide treatment of rooted Chrysanthemum cuttings controls
leafminer. Hortsci. 24: 856.
Saxena, R. C., Zhang, Z. T. & M. E. M. Boncodin (1993) Neem oil affects
courtship signals and mating behavior of Brown Planthopper Nilaparvata
lugens (Stal) (Homoptera: Delphacidae) females. J. Appl. Entomol.
(Zeitschrift fur Angewandte Entomologie). 116: 127-132.
Schmutterer, H. (1990) Properties and potential of natural pesticides
from the Neem tree, Azadirachta indica. Ann. Rev. Entomol. 35:271-297.
Schmutterer, H. (1992) Influence of azadirachtin, of an azadirachtin-
free fraction of an alcoholic Neem seed kernel extract and of formulated
extracts on pupation, adult emergence and adults of the Braconid
Apanteles glomeratus L. (Hymenoptera: Braconidae). J. Appl. Entomol.
(Zeitschrift fur Angewandte Entomologie). 113: 79-87.
Simmonds, M. S. J., Blaney, W. M., Ley, S. V., Anderson, J. C. & P. L.
Toogood (1990) Azadirachtin - Structural requirements for reducing
growth and increasing mortality in lepidopterous larvae. Entomol Exp.
Appl. 55:169-181.
Stark, J. D. (1992) Comparison of the impact of a Neem seed kernel
extract formulation, Margosan-O, and chlorpyrifos on non-target
invertebrates inhabiting turf grass. Pesticide Sci. 36: 293-299.
Verkerk, R. H. J. & D. J. Wright (1993) Biological activity of Neem
seed kernel extracts and synthetic azadirachtin against larvae of
Plutella xylostella L. Pesticide Sci. 37: 83-91.
Xie, Y. S., Gagnon, D., Aranson, J. T., Philog_ne, B. J. R. & J. D. H.
Lambert (1991) Effects of azadirachtin on the Western Corn Rootworm,
Diabrotica virgifera virgifera (Leconte) (Coleoptera: Chrysomelidae).
Can. Ent. 123: 707-710.
Yoshida, H. A. & N. C. Toscano (1994) Comparative effects of selected
natural insecticides on Heliothis virescens (Lepidoptera: Noctuidae)
larvae. J. Econ. Ent. 87: 305-310.
D. Casey Sclar
Colorado State University
Fort Collins, Colorado 80523
Summary: Overview of growth habits and culture of Azadirachta indica.
Commercial and experimental sources of Neem formulations. The mode of
action of azadirachtin and other principal chemical compounds present in
Neem extracts. The efficacy of various Neem formulations to arthropod
pests of ornamental plants and to non-target organisms. A discussion of
future directions in Neem research is presented.
Key Words:Neem, Azadirachtin, Antifeedant, Insect Growth Regulator,
Ornamental Plants, Botanical Insecticides.
I. Introduction:
In recent years, several reviews have been published which outline
the use of the Neem tree, Azadirachta indica (Meliaceae) as a botanical
insecticide (Jacobson, 1989; Koul et al. 1990; Schmutterer, 1990;
Ascher, 1993). The mode of action of azadirachtin, the principal
insecticidal constituent of Neem oil has only recently been elucidated
(Mordue & Blackwell, 1993). Little attention has been paid to recent
experiments involving Neem's use as an insecticide for arthropod pests
of ornamental plants (Cranshaw et al., 1993). This paper was written to
accomplish three functions: First, to acquaint the reader with the Neem
tree and sources of Neem oil available commercially and experimentally.
Second, to outline the mode of action of azadirachtin and the other
compounds present in Neem oil. Finally, a report on experiments
involving the use of Neem to control ornamental plant pests and efficacy
to non-target organisms is presented.
II. The Neem Tree:
The Neem tree, Azadirachta indica (Meliaceae) is native to
Southeast Asia and grows in many countries throughout the world
(Schmutterer, 1990; Ascher, 1993). It is closely related to the
Chinaberry tree, Melia azedarach (Meliaceae) (also called Persian
Lilac). M. azedarach contains several biologically active compounds.
Although more widely distributed than A. indica because of its hardier
nature and more pleasing appearance, the use of M. azedarach as a
natural insecticide is limited because it contains tetranitroterpenoid
compounds known as meliatoxins that are highly toxic to mammals (Ascher,
1993).
A. indica propagates readily from cuttings, stumps, tissue culture
or seed. Seed propagation in nurseries followed by direct planting
into the field is the accepted method to produce plantation stands
quickly and efficiently (Jacobson, 1989). It is widely used as a shade
tree in many areas (as is M. azedarach) because it tolerates a wide
variety of field conditions (Koul, 1990; Schmutterer, 1990). The tree
tolerates heat up to 50oC, and poor, shallow, even saline soils (Koul,
1990; Schmutterer, 1990; Ascher, 1993). A. Indica grows rapidly; 4-7
meters in its first five years of growth and 5-11m for the following
five years. It will bear fruit within three years and reach a maximum
fruiting yield of 50kg seed/year ten years after planting
(Jacobson,1989; Koul, 1990; Ascher, 1993). A. indica is sensitive to
injury at temperatures around 0oC, which limits its distribution in
temperate regions of the world (Jacobson, 1989; Koul, 1990; Ascher,
1993).
The Neem tree has many medicinal uses. Notable among these are its
use as an antiseptic and diuretic. It has been used to cure many
illnesses from diabetes to syphilis, and is widely relied upon by
herbalists in its native habitat (Jacobson, 1989; Koul, 1990). The use
of A. indica as a source of natural insecticide was discovered
approximately 30 years ago (Ascher, 1993).
III. Sources of Neem:
III.1 Within Plant Distribution
Seeds of the Neem tree contain the highest concentration of
azadirachtin and all other biologically active chemical compounds
present in A. indica. (Jacobson, 1989; Koul, 1990; Schmutterer, 1990).
Other tissues of A. indica known to contain these compounds at lower
levels are the bark, leaves and heartwood (Ascher, 1993). Because they
contain the highest concentrations of biologically active compounds,
most experimental and commercial preparations of Neem are seed extracts
(Jacobson, 1989). Aqueous, methanolic and ethanolic extracts of Neem
seeds show biological activity in the laboratory and the field,
although at a varying extent to different target organisms (Ascher,
1993).
III.2 Commercial and Experimental Sources of Neem
The first commercial Neem insecticide, Margosan-O_, was registered
by the EPA for non-crop use in the United States in July, 1985
(Jacobson, 1989). Since that time, the EPA has exempted Margosan-O_
from food crop tolerances and several other commercial Neem insecticides
have been developed worldwide (Ascher, 1993). Table 1 lists current
commercial and experimental suppliers of Neem extracts and formulations.
Table 1: Commercial and Experimental Sources of Neem Within the United
States (Adapted from Larson, 1993; Mordue & Blackwell, 1993)
Company Name and Address Trade Name Formulation (a)
AgriDyne Technologies, Inc. Turplex (formerly Azatin)C
417 Wakara Way
Salt Lake City, UT 84108
Gharda Chemicals Neemguard C
Bombay, India
Grace/Sierra, Inc. Margosan-O C
Iron Run Industrial Park
570 Grant Way
P.O. Box 789
Fogelsville, PA 18051
ITC Ltd. Wellgro, RD- Repelin C
Andhra Pradesh, India
Ringer Corp. Bioneem, Neemesis C
9959 Valley View Road (former Safer Ltd. products
Eden Prairie, MN 55344 consolidated here)
Rohm & Haas Co. RH - 9999 E
Independence Mall West
Philadelphia, PA 19105
Trifolio M GmBH Neemazal C
D-6335
Lahnau 2, Germany
USDA-ARS N/A E
National Center for Agricultural
Utilization Research
Peoria, IL 61601
Valent USA Corp. AD 1000 E
1333 N. California Boulevard #600
P.O. Box 8025
Walnut Creek, CA 94526-8025
West Coast Herbochem Neemark C
Bombay, India
a Key: C = Commercial, E = Experimental
Experimental sources of Neem remain cryptic. Within the United
States of America, only the USDA-ARS is a consistent supplier of raw,
unprocessed Neem seeds. Individual research laboratories may have
sources not known by the author.
IV. Modes of Action of Neem Oil Compounds:
IV.1 Overview
All biologically active Neem compounds are suspected to be derived
from one parent compound, the tetracyclic triterpenoid tirucallol (Fig.
1). All other products formed are considered successive rearrangement
and oxidation products of tirucallol (Ascher, 1993). It is generally
accepted that the tetranotriterpenoid (also called limonoid) compound
azadirachtin (Fig. 1) is responsible for the majority of biological
effects observed in organisms exposed to Neem compounds (Isman, 1990;
Mordue & Blackwell, 1993; Verkerk & Wright, 1993). However, 25
different biologically active compounds have been isolated from Neem
seeds (Lee et al., 1991). Other compounds present in Neem oil are
responsible for some of the biological activity observed (See - IV.4:
Other Effects of Neem).
Figure 1. The structures of tirucallol and azadirachtin
(Ascher,1993)
Within the azadirachtin molecule, the decalin fragment is
responsible for the insect growth regulation and development effects
observed, while the hydroxy furan fragment causes the antifeedant
effects more widely observed among target species (Fig. 2)(Aldhous,
1992). The IGR and antifeedant effects of azadirachtin are independent
of each other, but both remain relative to concentration (Koul & Isman,
1991).
Figure 2. The decalin and hydroxy furan fragments of azadirachtin
(Aldhous,
1992)
IV.2 Antifeedant Effects of Azadirachtin
The antifeedant effects of azadirachtin are well known (for reviews
see Jacobson, 1989; Schmutterer, 1990; Ascher, 1993; Mordue and
Blackwell, 1993). Both primary and secondary antifeedant effects have
been observed in the case of azadirachtin (Ascher,1993). Primary
effects include the process of chemoreception by the organism (e.g.
sensory organs on mouthparts which stimulate the organism to begin
feeding) whereas secondary processes are effects such as gut motility
disorders due to topical application only (Schmutterer, 1990;
Ascher,1993). Inhibition of feeding behavior by azadirachtin results
from blockage of input receptors for phagostimulants or by the
stimulation of deterrent receptor cells or both (Mordue & Blackwell,
1993). In a recent study by Yoshida and Toscano (1994), the relative
consumption rate of Heliothis virescens larvae treated with azadirachtin
was 25% of the control, attributing to the lowest assimilation
efficiency of all natural insecticides tested. In another study, larvae
of Heliothis virescens consumed less food, gained less weight, and were
less efficient at converting ingested and digested food into biomass
(Barnby & Klocke, 1987). Sensitivity between species to the
antifeedant effects of azadirachtin are profound. Order Lepidoptera
appear most sensitive to azadirachtin's antifeedant effects, with
Coleoptera, Hemiptera and Homoptera being less sensitive (Mordue &
Blackwell, 1993).
IV.3 Insect Growth Regulatory Effects of Azadirachtin
The insect growth regulatory effects of azadirachtin (in contrast
to its antifeedant effects) are remarkably similar among species (Mordue
& Blackwell, 1993). Various developmental, post-embryonic, reproductive
and growth inhibitory affects have been observed, causing malformation
and mortality in a dose-dependent manner (Ascher, 1993).
Schmutterer (1990) suggested that azadirachtin modifies the
programs of insects by influencing hormonal systems, especially that of
ecdysone. The effects of azadirachtin are both dose and time
dependent, prevent both ecdysis and apolysis, and can cause death before
or during molting, possibly inducing "permanent" larvae (Mordue &
Blackwell, 1993). Exogenous application of growth hormones did not
deter the effects of azadirachtin, leading researchers to suggest that
the most probable site of action of azadirachtin is at the site of
synthesis and release of Prothoracicotropic hormone (PTTH) (Koul and
Isman, 1991). The main action of azadirachtin appears to be at the
release sites of PTTH from the corpora cardiaca. Azadirachtin appears
to block the release of neurosecretory material from the corpora
cardiaca resulting in a reduced turnover rate. This affects the rate of
synthesis of PTTH by brain neurosecretory cells (Barnby & Klocke, 1990;
Mordue & Blackwell, 1993). Marco et al. (1990) stated that azadirachtin
caused a significant depletion of immunoreactive ecdysteroids in
Tenebrio molitor pupae. T. molitor has no PTTH glands and yet is still
sensitive to the ecdysteroid antagonistic effect exhibited by exposure
to azadirachtin. A possible explanation for this phenomenon could
involve epidermal cells or oenocytes being affected as both are
suggested as alternative sites of ecdysteriod production. It should be
noted that all these effects are working in conjunction with blockages
in JH (juvenile hormone) and allotropin titers, collectively resulting
in both molting and reproductive aberrations. It is assumed that
azadirachtin has direct effects on a variety of tissues and organs. This
suggests either a number of different modes of action or a specific
toxic lesion to all cells which manifests itself more obviously in some
cells than others (Mordue & Blackwell, 1993). All insect growth
regulatory effects of azadirachtin are suggested by Schmutterer (1990)
to be indirectly influenced by temperature, with greater activity seen
at higher temperatures.
IV.4 Other Effects of Neem (Unconventional Effects)
It has been noted that the presence of azadirachtin alone is not as
toxic as all Neem oil components present together (Verkerk & Wright,
1993). Other compounds present in Neem seed extracts besides
azadirachtin exhibit biological activity in myriad ways (Ascher, 1993).
Blaney et al. (1990) found that salinnin and nimbin, two other compounds
present in Neem seed extracts, exhibit an entirely different mode of
action than azadirachtin. Effects which may be exhibited by one or more
compounds present in Neem seed extracts include: oviposition repellency,
egg sterility, longevity, fitness and inhibition of chitin biosynthesis
(Ascher, 1993).
Use of a commercial formulation of Neem (RD-Repelin) successfully
deterred aphids attempting to land, probe or oviposit (Hunter and
Ullman, 1992). Lowery & Isman (1993) suggest that this deterrence
results from a variety of compounds working in concert with one another,
producing different behavioral responses which vary in magnitude between
species. Schmutterer (1990) reported reduced fecundity and longevity in
aphids treated with Neem seed extract. Treatment with Neem oil resulted
in a reduction of eggs produced and increased incubation time for eggs
of the spider mite Tetranychus urticae (Dimetry et al., 1993). Neem
inhibited adult eclosion and reproductive potential in Liriomyza
trifolii, as well as longevity of adults surviving treatment as eggs or
larvae (Parkman and Pienkowski, 1990). A reduction in transmission of
aphid-borne viruses in some species has also been observed (Hunter &
Ullman, 1992; Mordue & Blackwell, 1993).
It is suggested that Neem compounds which are present in solid form
in or upon leaf surfaces are responsible for these effects. Evidence
supporting this hypothesis is the study of Pathak & Krishna (1991) in
which Eucalyptus oil volatiles adversely affected growth and
reproduction of Corcyra cephalonica whereas exposure to Neem oil
volatiles had no effect.
Other effects of Neem are more behavioral in nature. Saxena et al.
(1993) reported that Neem disrupted mating signals in Nilaparvata lugens
(Homoptera: Delphacidae). Some insects failed to produce calls, while
others emitted unrecognizable calls.
V. Use of Neem Oil for Ornamental Plant Pest Control:
V.1 Use of Neem to Control Greenhouse Ornamental Plant Pests
Larew (1990) reviewed the use of Neem against pests of greenhouse
crops. The resistance of greenhouse pests to many insecticides and the
introduction of new pests (e.g. the Sweetpotato Whitefly - Bemesia
tabaci) to the greenhouse environment continue to complicate the
production of ornamental greenhouse crops. Although Schmutterer (1990)
suggested that the use of Neem may not be suitable for crops with high
quality demands, many successes have been reported using Neem
formulations to control pests on greenhouse ornamental plants.
Chrysanthemum Leafminer (Liriomyza trifolii) is an extremely
devastating pest of indoor greenhouses. Using Neem extracts, greenhouse
population levels of this pest were significantly reduced (Parkman and
Pienkowski, 1990). Leafminer infestations occur primarily by the
introduction of infested cuttings into the greenhouse. Sanderson et al.
(1989) observed decreased larval population and adult emergence level
after drenching boxed cuttings with Neem oil before shipping. Ascher et
al. (1992) used the commercial Neem formulation Azatin (now called
Turplex) to successfully reduce nymphal populations of Frankliniella
occidentalis, a thrips species difficult to control with conventional
insecticides.
Whiteflies represent perhaps the biggest challenge to growers of
greenhouse ornamental crops. Lindquist et al. (1990) reported the
efficacy of Neem against both susceptible and binfenthrin-resistant
populations of the Greenhouse Whitefly (Trialeurodes vaporarium). Price
and Schuster (1991) conducted field trials using Neem and various other
synthetic insecticides to control populations of Bemesia tabaci on
Poinsettia plants. Their data show that although Neem was slower to
display an initial effect, it ultimately yielded a level of control
comparable to that of many synthetic insecticides. This effect was
present without the phytotoxicity to leaves and bracts commonly
associated with the use of synthetic insecticides on Poinsettias.
V.2 Use of Neem to Control Pests of Landscape Ornamental Plants
Not since the review in Jacobson (1989) has the use of Neem for
control of landscape plant pests been addressed. During that time, new
developments have surfaced in the use of Neem for this purpose.
Schmutterer (1990) noted antifeedant effects of azadirachtin to Japanese
Beetle (Popillia japonica), a major pest of landscape plants in North
America. A reduction in field populations of aphids of various species
was reported by Lowery et al. (1993) at a level of control similar to
that of pyrethrum, another botanical insecticide. In a subsequent
paper, Lowery & Isman (1993) state that the settling and probing
behavior of the resistant aphid species Myzus persicae was not deterred
by Neem compounds, although the behavior of two other aphid species
(Sitobion avenae and Rhopalosiphum padi) was successfully its use.
Stark (1992) suggested that Neem would be useful as part of a turfgrass
IPM program. Recently, Cranshaw et al. (1993) reported the efficacy of
several commercial formulations of Neem against eggs and larvae of the
Elm Leaf Beetle (Xanthogaleruca luteola) in laboratory and field trials.
VI. The Efficacy of Neem to Non-Target Organisms:
Neem's efficacy to non-target and beneficial organisms has been
documented in previous and recent literature (Jacobson, 1989;
Schmutterer, 1990; Ascher, 1993; Mordue & Blackwell, 1993). Table 2
summarizes the effects of various formulations of Neem to several
different organisms. Because the amount of azadirachtin and other
compounds present in Neem oil is often not quantified by researchers,
the long-assumed benign effects of Neem to non-target organisms listed
below may be questionable (Stark, 1992). For this reason, data
presented in Table 2 is of qualitative nature only. As stated
previously, Neem is widely utilized in the tropics by humans for
medicinal purposes, and is assumed to have no detrimental effects to
humans with the exception of one trial in which an aflatoxin-
contaminated carrying agent is suspected to have been present (Jacobson,
1989; Schmutterer, 1990).
VII. Conclusion: Future Directions in Neem Research:
In the future, researchers will continue to elucidate the modes of
action of azadirachtin at a cellular level, and investigate the
mechanisms of biological activity exhibited by the other chemical
components found in Neem oil (Mordue & Blackwell, 1993). Other areas
which may be focused upon are insect resistance to azadirachtin and Neem
oil, the possible use of Neem as a systemic chemical and the stability
of Neem compounds in the field . Neem offers promise in the fight
against pesticide resistance, because of the diverse mode(s) of action
of azadirachtin and other Neem-associated compounds (Jacobson, 1989;
Ascher, 1993). It was recently hypothesized that the type of host plant
involved in a given situation may effect Neem's efficacy against a
particular pest (Lowery et al., 1993). What impact this will have in
future experiments remains to be seen.
Table 2: A selective summary of the effects of compounds present
in Neem extracts against non-target organisms and beneficial insects.
Organism Effect Level Reference Comments
Predaceous Spiders:
Lycosa pseudoannulata NE (Schmutterer, 1990)
Chiracanthium mildei NE (Schmutterer, 1990)
Predaceous Mites:
Phytoseiulus persimilis NE (Schmutterer, 1990) Some mortality
observed
but significantly
less than
that of target
organism
Oribatid Mites: OA (Stark, 1992)
Predaceous Coccinellids:
Delphastus pusillus NE (Schmutterer, 1990) No effect when
either
(Hoelmer et al., 1990) plant or prey
eggs treated
Predaceous Hemiptera:
Perillys bioculatus OA (Mordue & Blackwell,
1993)
Honeybees:
Apis mellifera NE (Schmutterer, 1990) No effect in
colonies of
> 200 individuals
Hymenopterous Parasitoids:
Aleurodiphilus sp. OA (Price & Schuster,
1991)
Apanteles glomeratus NE (Schmutterer, 1992) Below 40ppm/ AZ
Aphidius cerasicola NE (Schmutterer, 1990)
Cotesia congregata OA (Mordue & Blackwell,1993)
Dieratiella rapae NE (Schmutterer, 1990)
Encarsia sp. OA (Price & Schuster, 1991)
Telenomous remous OA (Schmutterer, 1990) Reduced longevity
Collembola: NE (Stark, 1992)
Rainbow Trout OA (Jacobson, 1989)
(Schmutterer, 1990)
a Key: NE = No biological effect observed, OA = Organism affected by
treatment
Recent reviews validated the theory that Neem has systemic action
(Ascher, 1993; Mordue & Blackwell, 1993). Xie et al. (1991) used soil
drenches of Neem to control laboratory populations of the Western Corn
Rootworm, Diabrotica virgifera virgifera and noted persistent effects
to adults feeding on plants as well as to the subterranean grubs and
pupae treated.
A foliar spray application of most commercial Neem formulations
persists 5-7 days under field conditions (possibly longer due to some
systemic effects) (Schmutterer, 1990). Even though breakdown of
azadirachtin occurs in UV light, its metabolites may still have
bioactivity (Ascher, 1993). Dihydroazadirachtin, a compound obtained by
hydrogenation of the C-22, 23 double bond of the hydroxy furan fragment
of azadirachtin, currently shows promise as a more stable compound for
better field persistence (Mordue & Blackwell, 1993). In previous
studies, hydrogenation of the hydroxy furan fragment resulted in no
decrease in bioactivity of the molecule (Blaney et al., 1990).
The types of substitutions made to the azadirachtin molecule are
important in the efficacy of the compound to target organisms. Several
different bioactive forms of the azadirachtin molecule exist.
Substitutions at some positions on the molecule will increase efficacy
to a particular target organism whereas other substitutions will result
in decreased efficacy to the same species (Simmonds et al., 1990).
Pure chemical synthesis of the azadirachtin molecule was once thought to
be impractical because of the difficult steps involved and the size of
the molecule. However, the group of Ley and Simmonds at Imperial
College in London have recently reported the success at the synthesis of
both the decalin fragment and the hydroxy furan fragment, with only the
linkage of the two fragments remaining to form the entire molecule of
azadirachtin in vitro (Aldhous, 1992). Future chemical synthesis of the
azadirachtin molecule and chemical mimics hold promise for the discovery
of safe pesticides with faster knockdown activity. This synthesis may
yield the ability to create and test each chemical component of Neem oil
in an isolated environment. Experiments of this nature would allow
researchers to continue to unravel the mystery surrounding the activity
of Neem compounds. Research of this type enhances the existing
knowledge of how Neem controls insects and mites, allowing better use of
this product by consumers, growers, farmers, and researchers.
VIII.Literature Cited
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Ascher, K. R. S. (1993) Nonconventional insecticidal effects of
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