Neem oil is obtained from the seeds of the Indian neem tree, or Azadirachta indica. For centuries, people have used neem oil for cosmetic purposes and to deter insects and fungal disease from agricultural crops. The oil is commonly used in Ayurvedic medicine to treat gastrointestinal ailments, inflammatory disorders and intestinal parasitic infections. Neem oil has several ingredients, most of which are collectively referred to as triterpene compounds and triglycerides.
Azadirachtin
Azadirachtin belongs to the class of phytochemicals known as limonoids, the same chemicals found in citrus fruits. According to the U.S. Environmental Protection Agency, or EPA, this ingredient is what makes neem oil an effective, natural pest control. When sprayed on food and non-food plants, this chemical targets specific insects, including mites, aphids and whiteflies. Not only does this chemical deter such pests from foraging on leaves, it also disrupts their reproductive cycles. When used as directed, neem oil does not present toxicity for humans or other non-targeted species, including beneficial garden organisms and birds. However, the EPA cautions against using neem oil while honeybees are active. (Reference 1)
The pest information profile provided by Cornell University further describes the physiological effects this ingredient has on certain insects. Azadirachtin appears to block the activity of ecdysones, insect hormones that regulate metamorphosis, which means that pupa cannot molt and graduate to the adult stage. (Reference 2)
Steroids
According to the “Physicians’ Desk Reference for Herbal Medicines," neem oil contains a number of plant sterols. These agents, which include beta-sitosterol, campesterol and stigmasterol, are chemically similar to animal cholesterol. (Reference 3)
Fatty Acids
An article that appeared in the Dec. 28, 2000 issue of Biochemical Society Transactions reported that neem oil is abundant in several fatty acids in varying concentrations. According to the authors, the average composition of neem oil includes 25 to 54 percent oleic acid, also known as omega-9 fatty acid, 16 to 33 percent palmitic acid, up to 24 percent stearic acid and trace amounts of omega-3, omega-6 and palmitoleic acid. (Reference 4)
Other Ingredients
The “Physicians’ Desk Reference for Herbal Medicines” says that neem oil contains several other limonoids and protolimonoids that are collectively referred to as Gedunin derivatives. Individually, these include nimbolin A, nimbolin B, nimbin (2), nimbidin and gedunin. (Reference 3) According to a study published in the Sept. 25, 2008 issue of the Journal of Medicinal Chemistry, Gedunin has demonstrated anticancer activity in breast cancer cells. (Reference 5)
References
- U.S. Environmental Protection Agency: Azadirachtin (121701) Clarified Hydrophobic Extract of Neem Oil (025007) Fact Sheet
- Cornell University Cooperative Extension: Azadirachtin
- “PDR for Herbal Medicines”; Thomas Fleming, Chief Editor, et al; 2000
- Biochemical Society Transactions; Variations in Fatty Acid Composition of Neem Seeds Collected from the Rajasthan State of India; Kaushik N and Vir S; 2000 Dec;28(6):880-2
- Journal of Medicinal Chemistry; Gedunin, a Novel Hsp90 Inhibitor: Semisynthesis of Derivatives and Preliminary Structure−Activity Relationships; Gary E et al.; 2008, Sept. 25, 51 (20), pp 6495–6502
Member Comments