NeemAzadirachta indica

Did you know?

• Neem is widely planted along avenues and around homes for its shade, which it gives all year round^{[1, 7]}.

• Neem belongs to the mahogany family, and its wood is valued as timber^{[1, 3, 4]}. It is made into wardrobes and bookcases, because insects tend to leave it alone^[7].

• For centuries, farmers in India have mixed neem leaves into their stored grain to keep insects away^{[1, 4]}.

• The seed oil has been burned in lamps and made into soap^{[1, 7]}.

• Azadirachtin, found mainly in the seed kernels, is used in organic farming to protect crops from insects^{[1, 3, 7]}.

• In Saudi Arabia, a forest of 50,000 neem trees was planted on the Plains of Arafat to shade the pilgrims who camp there each year^[1].

Origins and history

Neem is a tree of hot, dry country. It usually grows 15 to 20 meters (50 to 65 feet) tall, with spreading branches that form a broad, rounded crown, and it keeps its leaves all year except in severe drought^{[1, 4, 7]}. It thrives where the shade temperature climbs past 50 °C (122 °F), and a tree may live for more than two centuries^[1]. Its small white flowers have a honey-like scent and draw many bees^[1], and its fruits each hold a single seed rich in oil^{[1, 4]}. Botanists still debate where it first grew: Kew gives its native range as Assam, Bangladesh, Myanmar and Indochina, while Britannica calls it likely native to the Indian subcontinent and the dry areas of South Asia^{[2, 3]}. In India it is grown from the southern tip of Kerala to the Himalayan foothills, and in the twentieth century it was carried to Africa, where it now grows in many countries south of the Sahara^{[1, 2]}. It is also planted in the Caribbean and in Central and South America^{[1, 2]}. Neem is sometimes confused with the chinaberry or Persian lilac (Melia azedarach), a different tree of the same family^[1].

In India, neem is a tree of everyday use. People plant it for shade^{[1, 7]} and have long tucked its leaves into grain stores to keep insects out^{[1, 4]}. The young leaves and flowers are cooked and eaten; they are very bitter and are often served before a meal^[7]. The seeds are pressed for an oil that has fueled lamps and been refined into soap and cosmetics^{[1, 7]}, and neem seed extracts are now used in organic farming^{[1, 3, 7]}. Neem is also central to Ayurveda and Unani, the traditional systems of India, where almost every part of the tree has a use^{[1, 4, 5]}.

Traditional uses

Clinical studies of neem leaf in people are still few, but its traditional use in India is long and rich, and nearly every part of the tree has a place in it^{[1, 4, 5]}.

• A twig for the teeth

  A fresh neem twig is chewed at one end until it frays into a brush, then used each morning to scrub the teeth and gums.^{[1, 7]}

• Healthy-looking skin

  In Ayurvedic tradition, neem leaves are applied to the skin as a paste or a strong tea. Neem leaf supports healthy-looking skin.*^{[1, 5]}

• Healthy digestion

  The very bitter leaf has traditionally been taken for the digestion. Neem supports healthy digestion.*^{[5, 7]}

Plant compounds

Neem's best-known plant compounds are limonoids, a family of triterpenoids. They include azadirachtin, concentrated in the seed kernels, together with nimbin, nimbidin and salannin^{[1, 4]}.