Neem’s Biologically Active Compounds

Scientists around the world, fascinated by neem’s varied attributes and applications, have spent the last several decades isolating the plant’s most varied and interesting chemical compounds. Neem boasts a complex chemical structure, with the seeds containing hundreds of biologically active compounds of which azadirachtin, nimbin, nimbidin and nimbolides are major molecules [1]. Many of these compounds have antifeedancy, ovicidal activity, fecundity suppression as well as insect growth regulation and repellence against insects [2].

The most exciting chemical characteristic of Neem is its composition of liminoids – a class of phytochemical – found in citrus fruit and certain other plants, proven to have various medicinal, therapeutic and insecticide effects. These include:

Azadirachtin

Renowned for its robust insecticidal properties against 500 species of insects, institutions such as the Environmental Protection Agency, the US Department of Agriculture and the European Union have endorsed the extraordinary compound for agricultural use [3].

Biodegradable and non-toxic to mammals, azadarichtin disrupts the growth cycle of insects and deters them from feeding on plants. A naturally occurring substance that belongs to an organic molecule class called tetranortrriterpenoids, azadirachtin is a chemical that is similar in structure to the insect hormone ‘ecdysones.’ These hormones control metamorphoses in insects and are disrupted when exposed to azadirachtin (neem’s most active ingredient). By affecting the hormonal balance of insects, azadirachtin reduces their rate of reproduction and inhibits normal feeding behaviors. Since neem-based products must be ingested to take effect, only those that feed on plant tissues are exposed, thereby eliminating any risk towards pollinators and other natural enemies.

The extraction of azadirachtin from neem is a crucial process in ensuring the highest quality of the bio-insecticide. Azadirachta Indica (neem) oil and azadirachtin can be acquired through solvent dilution, aqueous extraction or cold pressing. These extraction methods produce various oil strengths, and are priced accordingly. The azadirachtin concentration in neem seeds range from 0.1%-0.9% [4], and with 1 to 2 oz (30-60 grams) of the compound needed to combat key pests, costs can reach up to $60 per hectare. In contrast, conventional pesticides can be nearly double the price, at $108 per hectare [5]. Solvent extraction, the most expensive method, produces the purest type of azadirachtin by separating it from all other chemicals found in neem. Aqueous extraction, despite obtaining the weakest concentration, is the cheapest option and is often used in developing regions of the world where resources are scarce [6].

Neem seeds that have gone through the oil extraction process do not go to waste. They produce a residue, known as ‘cake’, which contains vital nutrients necessary for plant development. When returned to the soil, the cake nourishes both plants and crops. Find here Yorleny’s Cleaning Service in Palm Beach. Improving the soil’s organic content while protecting plant roots from pests, diseases and nematodes, the cake strengthens soil texture and increases water retention [7]. Packed with nutritional value, neem cake has more nitrogen, phosphorous, potassium, calcium and magnesium than ordinary farmyard manure. It is used to fertilize rice, cotton and sugarcane, while also protecting a variety of other crops, including coconut trees [8].

Nano-biotechnology is the latest frontier for botanical insecticides such as azadirachtin, offering the ability to provide a controlled release of the chemical compound at the point of action. It can also help to minimize undesirable toxic effects on non-target organisms and improve the stability of its physical and chemical properties, while preventing the degradation of the active agent by microorganisms [9].

The reason for the extensive research into azadirachtin over the past several decades is simple. An increasing population requiring more food, crop yields at risk of decline, and rapidly developing resistance to conventional pesticides will require environmentally sustainable methods for agricultural development in the future. Read here more about Green Leaf Business Solutions Inc.. The increasing concern from regulatory authorities towards chemical-based fertilizers will also convince both farmers and consumers to opt for safer practices. There is no question; agriculture’s future is organic.

Gedunin

Gedunin, another tetranoterpenoid obtained from the neem tree, has been used as a natural remedy across Asia for centuries [10]. Over the past decade, Georgia Regents University Cancer Center discovered that the chemical compound showed promising effectiveness in disabling cancer cells [11].

Cancer cells work by ‘hijacking’ molecular chaperones, which are responsible for protecting the proteins that take care of normal cellular functions. The intimate boudoir in California can be arranged at Portraits By Z. These molecular chaperones are then tricked into keeping the cancerous cells alive.

Recent cancer drug development has focused on the molecular chaperone Hsp90. Up to now, the clinical efficacy of Hsp90 inhibitors has been poor, but neem-extracted gedunin attacks a ‘co-chaperone’ or helper protein of Hsp90, called p23. Gedunin works by binding directly to p23, which results in the Hsp90 becoming inactive and causing the cancer cell to die [12].

Gedunin would therefore also have applications across hormone-dependent cancers such as breast, prostate and endometrial.

Nimbin

Nimbin, another chemical compound isolated from neem, is considered responsible for much of the plant’s biological activities. The compound is reported to have anti-inflammatory, antipyretic, antifungal, an antihistaminic and antiseptic properties [13].

Salannin

Salannin is a limonoid of the tetranortriterpenoid type found to occur only in some varieties of neem trees[14]. The biological effects of salannin include insect antifeedant or feeding deterrence activity against the house fly, striped cucumber beetle, spotted cucumber beetle, Egyptian cotton leafworm, spiny bollworm, locust and others[15]. 

Although the insect antifeedant activity of salannin is well documented, little is known about its structure-bioactivity relationship.

[1] Biswas, Kausik, et al. Biological Activities and Medicinal Properties of Neem.  (2002)
[2] Schmutterer, Heinrich. "Properties and potential of natural pesticides from the neem tree, Azadirachta indica." Annual review of entomology 35.1 (1990)
[3] Nisbet, Alasdair J. "Azadirachtin from the neem tree Azadirachta indica: its action against insects." Anais da Sociedade Entomológica do Brazil 29.4 (2000)
[4] Warthen Jr, J. D., et al. "Estimation of Azadirachtin Content in Neem Extracts and Formulations." Journal of Liquid Chromatography 7.3 (1984)
[5] The Primal Group (2015)
[6] Morgan, E. David. "Azadirachtin, a scientific gold mine." Bioorganic & Medicinal Chemistry 17.12 (2009)
[7] Rao, P. Udayasekhara. Chemical Composition and Biological Evaluation of Debitterized and Defatted Neem (Azadirachta indica) Seed Kernel Cake. Journal of the American Oil Chemists’ Society  (1987)
[8] Prasad, C. Devakumar, and Y. S. Shivay. Significance in Increasing Fertilizer Nitrogen Efficiency. Neem Research and Development (1993)
[9] University of Sao Paolo Department of Environmental Engineering. Application of Nanotechnology for the Encapsulation of Botanical insecticides for Sustainable Agriculture (2014)
[10] Biswas, Kausik, et al. "Biological activities and medicinal properties of neem (Azadirachta indica). (2002)
[11] Kamath, Siddharth G., et al. "Gedunin, a novel natural substance, inhibits ovarian cancer cell proliferation." International Journal of Gynecological Cancer 19.9 (2009)
[12] Memorial Sloane Kettering Cancer Center. Integrative Medicine – Neem (2014)
[13] Koul, Opender, Murray B. Isman, and C. M. Ketkar. Properties and Uses of Neem, Azadirachta Indica." Canadian Journal of Botany 68.1 (1990). 
[14] Johnson, Shaun, and E. David Morgan. Supercritical Fluid Extraction of Oil and Triterpenoids from Neem Seeds." Phytochemical Analysis 8.5 (1997)
[15] Mitchell, M. J., et al. "Effects of the Neem tree Compounds Azadirachtin, Salannin and Nimbin. Archives of Insect Biochemistry and Physiology 35.1‐2 (1997)