Azadirachtin

Description

Kernel extracts from the Indian neem tree (Azadirachta indica) have insecticidal and insect-repellent properties. The key active ingredient is azadirachtin, a nortriterpenoid that exhibits insect growth regulator effects but no adulticidal activity.

Description

Azadirachtin is an impressive molecule. It contains eight rings (five of which incorporate oxygen atoms), 16 chiral centers, and three quaternary carbon atoms. Its functionalities include a hydroxyl group, an enol ether, an acetal, two hemiacetals, an epoxide, and four carboxylic acid esters.
Synthetic organic chemists had a tough time synthesizing azadirachtin, but it came naturally to the neem tree (Azadirachta indica), a member of the mahogany family that grows in India, Iran, and parts of Africa. Azadirachtin, along with many related compounds, is found in neem seeds, leaves, and bark. Its biosynthetic pathway has not been completely elucidated.
For centuries, the seeds and leaves of A. indica have been known to repel harmful insects from agricultural crops. In the 1960s, chemists began to study neem seed extracts to determine the active ingredients. J. H. Butterworth and E. D. Morgan at the University of Keele (UK) identified azadirachtin as the key molecule in 1968. Stephen V. Ley and four co-workers at the University of Cambridge (UK) completed its prodigious total synthesis in 2007.
Azadirachtin is a white microcrystalline solid with a strong garlicky or sulfurous odor, which is a bit strange because it contains no sulfur. Perhaps the odor is what repels insects. In any case, neem oil (extracted from the seeds) is used in many commercial pesticides and growth regulators. Although azadirachtin has some toxic properties (see hazard information table), it is harmless to mammals in the amounts normally used. As the table also shows, however, it brings some environmental concerns.
Azadirachtin has another, perhaps unexpected, use. Much of the Indian population chews neem twigs or uses them as brushes to clean their teeth. Taking things further, neem bark, leaves, and oil are used in many “natural” toothpastes. You can purchase all of these products in health food stores or online.

Chemical properties

Off-white, yellowish powder or dark brown emulsifiable concentrate.

The Uses of Azadirachtin

Azadirachtin is a tetranortriterpinoid isolated from the seeds of the neem tree. Highly active insect feeding deterrent and growth regulator.It is used experimentally as insect control agent.

The Uses of Azadirachtin

Azadiractin is extracted from the neem tree (Azadirachta indica). It is the principal active ingredient of extracts of neem. Neem extracts and pure azadirachtin are used to control whitefly, leaf miners and other pests including pear psylla.

What are the applications of Application

Azadirachtin is a highly oxidized tetranortriterpenoid

Definition

ChEBI: A member of the family of azadirachtins that is isolated from the neem tree (Azadirachta indica).

Agricultural Uses

Insecticides, Nematicide: Azadirachtin is an extract of fruit from the Neem tree, which is largely grown in India. It is used as a commercial insect growth regulator that controls the metamorphosis process as the insect passes from the larva stage to the pupa stage. The Neem tree also yields extracts from its bark, leaves and wood that are used in medicine and cosmetics.

Trade name

ALIGN®; AZATIN EC®; AZATIN®-XL PLUS; AZATROL EC®; AMAZIN® ECOZIN® EI- 783®; MARGOSAN-O®; NEEM®; NEEMAZAL®; ORNAZIN® SALANNIN®; SUPERNEEM®; TURPLEX®

Biochem/physiol Actions

Triterpenoid found in need tree seeds, azadiractin suppresses feeding by many insect species and disrupts growth of most insect and other arthropod species, while having very low mammalian toxicity. Promising as a natural pesticide.

Potential Exposure

Biological tetranortriterpinoid insecticide; insect growth regulator. A natural product extracted from seeds of the Neem tree (Azadirachta indica).

Metabolic pathway

The natural insecticide azadirachtin is most stable in mildly acidic solutions between pH 4 and 6 at room temperature and unstable in alkaline and strong acidic conditions. While azadirachtin is relatively stable to heating in the seeds or as a pure solid, it is rapidly destroyed or altered by heating in aqueous solution and methanol. In methanol at 90°C, it is quantitatively converted to 3-acetyl-1-tigloylazadirachtinin.

Shipping

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Degradation

After 90 hours exposure to UV radiation, very little azadirachtin (l)its 3- acetyl derivative and 22,23-dihydroazadirachtin remained intact. However, these compounds retained biological activity, and at least 200 hours irradiation was necessary to reduce the biological activity of 1. It is suggested that the effect of ultraviolet radiation is confined to the tigloyl residue which is common to these three compounds and which may undergo cis-trans isomerisation, rearrangement, etc. without significant effect on the biological activity of the molecule, because reduction or removal of the tigloyl residue causes only limited reduction in biological activity of the parent (Barnby ef al., 1989).
Azadirachtin was hydrolysed readily in several buffers (pH 4.1-8.1) and natural waters (pH 6.2,7.3,8.0 and 8.1) at 35 °C and its disappearance followed pseudo-first-order kinetics (Szeto and Wan, 1996). Rates of disappearance of the parent were faster in basic than in acidic solution (DT₅₀ was 12 hours at pH 8 and 206 hours at pH 6) and the compound is not expected to be persistent in water.

Mode of action

Azadirachtin acts on insect gustatory receptors to inhibit feeding, and also interferes with development by inhibiting synthesis of the neuropeptide that triggers ecdysone release. The molecular targets mediating these effects are not known.

Toxicity evaluation

Azadirachtin is practically non-toxic to mammals, birds and plants. It is moderately toxic to aquatic invertebrates, but exposure is negligible due to low application rates and rapid degradation. Since it is only active by ingestion of treated foliage, exposure of non-target insects and honeybees is minimal.

Incompatibilities

Powder or liquid may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, reducing agents and metals, acid chlorides, alkalis, alkali metals, high heat, including sunlight.

Waste Disposal

Waste product may be disposed of onsite (open dumping may be prohibited) or at an approved waste disposal facility. All federal, state, and local environmental regulations must be observed.