Neem tree

The seeds from the Indian neem tree, Azadirachta indica, are the source of two types of neem-derived botanical insecticides neem oil and medium polarity extracts. Neem seeds contain numerous azadirachtin (Fig. 9) analogs, but the major form is azadirachtin and the remaining minor analogs are likely to contribute little to the overall efficacy of the extracts. Typically, solvent partitions or other chemical processes are required to concentrate this active ingredient to the level of 10% to 50% seen in the technical grade material used to produce commercial products. 

Jacobson, M. In "Natural Pesticides from the Neem Tree (Azadirachta Indica A. Juss.)" Schmutterer, H. Ascher, K.R.S. Rembold, H., Eds. German Agency for Technical Cooperation Eschborn, Germany, 1980 pp. 33-42,... 

Other naturally derived aflatoxin inhibitors obtained from the "neem" tree have been investigated in our laboratory (84), Azadirachta indica Juss. commonly known as "margosa" or "neem" is an ornamental tree of Asia and Africa that produces natural products having reputed value for their medicinal, antiviral, antibacterial, insecticidal, antifungal and antinematode properties (86, 87). Several active principles from different parts of the neem tree have been reported (88). Our investigation (84) examined the effects of these neem leaf components in neem leaves on aflatoxin biosynthesis by either Aspergillus parasiticus or A. flavus. 

Jacobson, M. "The Neem Tree National Resistance Par excellence" In National Resistance of Plants to Pests American Chemical Society Publications pg. 225. 

Many triterpenes also have anti herbivore activity. In general, those which are highly oxygenated seem to be more active in this regard M). The role of cardiac glycosides, insects and their predators has been reviewed (91-94). A number of metabolically altered triterpenes from the Rutaceae, Meliaceae and Simaroubaceae are antifeedants. Extracts of neem tree seeds (Azadirachta indica. Meliaceae) were shown to be repellent to a number of insects when applied to various crop plants at low concentrations. The probable active compound is tetranortriter-pene, azadirachtin (9 ). This compound from the leaves and fruits... 

H. Schmutterer (ed.), The Neem Tree Azadirachta indica A. Juss. and Other Meliaceous Plants Sources of unique natural products for integrated pest management, medicine, industry and other purposes , VCH, Wein-heim, 1995, 696 pp. 

Traditional insecticides were derived from plants. Key amongst them are nicotine and rotenone. Increasing interest is being shown in azadirachtin from the neem tree. The classical natural insecticide pyrethrin is derived from the flowers of Pyrethrum cinerariaefolium, from which the major insecticide group the pyrethroids were derived. 

A recent example is given by the insecticidal properties of the neem tree (Stone). Neem seeds have chemicals that ward off more than 200 species of insects, while exhibiting less toxicity to humans than synthetic pesticides, and having little effect on predators of the insects. Neem seeds were valued at 300/ton in 1992. However, a lower pnce is needed if the extracts are to find widespiead use as insecticides. The economic potential for naturally derived insecticides is large considering that about 2 x 109 of synthetic insecticides are sold annually in the U.S, (Stone). 

HPLC H NMR spectroscopy using an isocratic separation with acetonitrile and D2O in the ratio 7 13 has also been used to study photo-isomerisation of the natural material azadirachtin extracted from the seeds of the neem tree and which is a powerful insect anti-feedant [34], This has a complex structure with an (ii)-2-methylbutyl-2-enoate fragment but which after exposure to UY iradiation is converted to the Z-isomer ... 

Akhtar, M. Nematicidal potential of the neem tree Azadirachta indica (A. Juss). Integ Pest Manag Rev 2000 5 57-66. 

The powerful antifeedant and insecticide azadirachtin (213), from the neem tree (Azadirachta indica, Meliaceae), is a highly oxidized limonoid with rings A, B, and D intact.2 It is used as a benchmark against which all other antifeedants can be compared (vide infra). The total synthesis of azadirachtin has recently been achieved in 64 steps.96 This is very unlikely to provide a synthetic source of the compound, but it does allow SAR studies to find maximum activity, and opens up the field to possible simpler synthetics modelled on it. As yet, even slight modifications of the structure tend to decrease activity. Azadirachtin (213) has been available commercially, particularly in the United States, but at present the cost of the seeds and the isolation procedure inhibit its wider use. 

Limonoids are C2(, nortriterpenoids deriving from a C30 triterpene precursor. The best known limonoids are the Azadirachta indica (neem tree) antifeedant azadirachtin (C50L C40 C6 -C60(epoxide methylene cross-link) furan) and the Citrus species (Rutaceae) bitter antifeedant limonin (G50L G40 G6 G6 C50L(epoxide)-furan). Limonin gives a delayed bitter taste to Citrus fruit. The limonoids are typically bitter compounds with insect antifeedant activity... 

Azadirachtin Azadirachta indica (neem tree) V-K+CH (ECMOX) [insect... 

The synthesis of the limondd azadiradione, utiiizing a Hg° cyclization-oxidative demercuration sequence with an enol phosphate derived from trans,trans-famesol has been reported. Azadiradione, a te-tracarbocyclic memter of the iimonoid group isoiated from the neem tree, Azadirachta indica, has been converted to other tetracyclic limonoids, and is thus a key intermediate. The sequence is shown in Scheme 33. 

Azadirachtin extracted from Azadirachta indicta (neem tree)... 

Margosa oil, a long-chain fatty acid that is extracted from the seeds of the neem tree, has been implicated as a... 

Neem (also known as azadirachtin) is an insecticide extracted from the seeds of the neem tree (Azadirachta indica) common in most of Africa and India. It is closely related to the chinaberry tree (Melia azadarach), common in the southern and southeastern United States. Extracts of both trees have insecticidal properties. Neem is unique among pesticides since it has so many uses It acts as a broad-spectrum repellent, growth regulator, and insect poison. It discourages feeding by making plants unpalatable to insects if they still attack, it inhibits their ability to molt and lay eggs. 

In Insects, by some unknown mechanism, Is azadlrachtln (Figure 7), a tetranortrlterpenold of the llmonold type Isolated from the seeds of the neem tree, Azadirachta indica (Mellaceae) (36) and the fruits of the chlnaberry tree, Melia azedarach (Mellaceae)... 

Thailand, Burma, and East Africa. It is under cultivation in plantations of West Africa and the Caribbean islands, as well as parts of Central and South America. Two neem trees brought from India approximately 40 years ago are thriving in the Miami, Florida area of the United States and a nunber of the young trees cultivated from seed are doing well in Puerto Rico ( 1). When fully grown the tree can reach a height of 60 feet with a trunk diameter of 6 feet. 

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