Neem Tree is a tree in the family Mileaceae. (Scientific name: Azadirachta indica). This tree is found all over India.
It is typically grown in tropical and semi-tropical regions. Neem trees also grow in islands located in the southern part of Iran. Its fruits and seeds are the source of neem oil. Neem is a multipurpose tree that is highly popular in India, where it provides food and insecticide, and is used for its great number of ethnomedicinal properties. Neem leaves and the oil cake resulting from oil extraction can be used for livestock feeding, but the raw cake is poorly palatable, toxic and requires processing.
Neem leaves, bark and seed extracts have been used for centuries in India in ethnomedicine and ethnoveterinary medicine. The seeds are an important source of azadirachtin, a limonoid compound (triterpenoid) present in the seeds, and also to some extent in leaves and other tissues. It acts as an insect repellent, inhibiting them from feeding, thus disrupting their growth, metamorphosis and reproduction. Extracts or crude parts of the tree are often mixed with stored seeds such as maize, rice and beans, in order to protect them against insects. In India, neem-based pesticides have been developed. Neem extracts can protect plants from foliage-eating insects without affecting pollinating insects such as honeybees. Other neem limonoids have various properties. Melantriol and salannin act as antifeedants for insects. Nimbin and nimbindin (the latter a bitter compound present in the seed at 2%) were reported to have antiviral activity. The oil extracted from the seeds has industrial uses and is widely used in ethnomedicine in India. However, it contains various toxic substances (including some added to increase its alleged therapeutic effect) and has been the cause of the death of children. Neem provides valuable firewood, makes good charcoal and provides various environmental services.
Neem is native to India and Burma. It is the state tree of Andhra Pradesh. Neem is a fast growing tree that can reach a height of 15-20 m, rarely to 35-40 m. It is evergreen but under severe drought it may shed most or nearly all of its leaves. The branches are wide spread. The fairly dense crown is roundish or oval and may reach the diameter of 15-20 m in old, free-standing specimens. The trunk is relatively short, straight and may reach a diameter of 1.2 m. The bark is hard, fissured or scaly, and whitish-grey to reddish-brown. The sapwood is greyish-white and the heartwood reddish when first exposed to the air becoming reddish-brown after exposure. The root system consists of a strong taproot and well developed lateral roots. The alternate, pinnate leaves are 20-40 cm long, with 20-31 medium to dark green leaflets about 3-8 cm long. The shape of mature leaflets is more or less asymmetric and their margins are serrated. The flowers (white and fragrant) are arranged axillary, normally more-or-less drooping panicles which are up to 25 cm long. The inflorescences, which branch up to the third degree, bear 150-250 flowers. An individual flower is 5-6 mm long and 8-11 mm wide.The fruit is a glabrous olive-like drupe which varies in shape from elongate oval to nearly roundish, and when ripe are 1.4-2.8 x 1.0-1.5 cm. But Neem is far more than a tough tree that grows vigorously in difficult sites.
Neem leaf is used for leprosy, eye disorders, bloody nose, intestinal worms, stomach upset, loss of appetite, skin ulcers, diseases of the heart and blood vessels (cardiovascular disease), fever, diabetes, gum disease (gingivitis), and liver problems. The leaf is also used for birth control and to cause abortions.
Among its many benefits, the one that is most unusual and immediately practical is the control of farm and household pests. Some entomologists now conclude that neem has such remarkable powers for controlling insects that it will usher in a new era in safe, natural pesticides.