Azadirachta indica
| Neem | |
|---|---|
 | |
| Azadirachta indica, flowers & leaves | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| Order: | Sapindales |
| Family: | Meliaceae |
| Genus: | Azadirachta |
| Species: | A. indica |
| Binomial name | |
| Azadirachta indica | |
| Synonyms | |
| Melia azadirachta L. Antelaea azadirachta (L.) Adelb. | |
Neem is a fast-growing tree that can reach a height of 15–20 m (about 50–65 feet), rarely to 35–40 m (115–131 feet). It is evergreen, but in 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.
Trunk
The trunk is relatively short, straight and may reach a diameter of 1.2 m (about 4 feet).It is classified as a bush but it is not very weak.Leaves
The opposite, pinnate leaves are 20–40 cm (8 to 16 in.) long, with 20 to 31 medium to dark green leaflets about 3–8 cm (1 to 3 in.) long. The terminal leaflet is often missing. The petioles are short. Very young leaves are reddish to purplish in colour. The shape of mature leaflets is more or less asymmetric and their margins are dentate with the exception of the base of their basiscopal half, which is normally very strongly reduced and cuneate or wedge-shaped.Flowers
The (white and fragrant) flowers are arranged axillary, normally in more-or-less drooping panicles which are up to 25 cm (10 in.) long. The inflorescences, which branch up to the third degree, bear from 150 to 250 flowers. An individual flower is 5–6 mm long and 8–11 mm wide. Protandrous, bisexual flowers and male flowers exist on the same individual.Fruit
The fruit is a smooth (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. The fruit skin (exocarp) is thin and the bitter-sweet pulp (mesocarp) is yellowish-white and very fibrous. The mesocarp is 0.3-0.5 cm thick. The white, hard inner shell (endocarp) of the fruit encloses one, rarely two or three, elongated seeds (kernels) having a brown seed coat.The neem tree is very similar in appearance to the Chinaberry, all parts of which are extremely poisonous to mammals, while birds are known to gorge themselves on the berries, the seeds passing harmlessly through their unique digestive systems.
Ecology
The neem tree is noted for its drought resistance. Normally it thrives in areas with sub-arid to sub-humid conditions, with an annual rainfall between 400 and 1200 mm. It can grow in regions with an annual rainfall below 400 mm, but in such cases it depends largely on ground water levels. Neem can grow in many different types of soil, but it thrives best on well drained deep and sandy soils. It is a typical tropical to subtropical tree and exists at annual mean temperatures between 21-32 °C. It can tolerate high to very high temperatures and does not tolerate temperature below 4 °C . Neem is a life-giving tree, especially for the dry coastal, southern districts of India. It is one of the very few shade-giving trees that thrive in the drought-prone areas. The trees are not at all delicate about the water quality and thrive on the merest trickle of water, whatever the quality. In India it is very common to see neem trees used for shade lining the streets or in most people's back yards. In very dry areas the trees are planted in large tracts of land.Weed status
Neem is considered a weed in many areas, including some parts of the Middle East, and most of Sub-Saharan Africa including West Africa where in Senegal it has been used as a malarial drug and Tanzania and other Indian Ocean states where in Kiswahili it is known as 'the panacea', literally 'the tree that cures forty [diseases]', where ayurvedic uses are practiced.Ecologically, it survives well in similar environments to its own, for example replacing the babul acacia tree from India with African acacia species.
Chemical compounds
The Indian scientists were the first scientist to bring the plant to the attention of phytopharmacologists.] In 1942, while working at the Scientific and Industrial Research Laboratory at Delhi University, British India, he extracted three bitter compounds from neem oil, which he named nimbin, nimbinin, and nimbidin respectively. The seeds contain a complex secondary metabolite azadirachtin.Uses
In India, the tree is variously known as "Sacred Tree," "Heal All," "Nature's Drugstore," "Village Pharmacy" and "Panacea for all diseases." Products made from neem tree have been used in India for over two millennia for their medicinal properties: Neem products have been observed to be anthelmintic, antifungal, antidiabetic, antibacterial, antiviral, contraceptive and sedative.Neem products are also used in selectively controlling pests in plants. It is considered a major component in Ayurvedic and Unani medicine and is particularly prescribed for skin disease.- All parts of the tree are said to have medicinal properties (seeds, leaves, flowers and bark) and are used for preparing many different medical preparations.
- Part of the Neem tree can be used as a spermicide
- Neem oil is used for preparing cosmetics (soap, shampoo, balms and creams, for example Margo soap), and is useful for skin care such as acne treatment, and keeping skin elasticity. Neem oil has been found to be an effective mosquito repellent.
- Neem derivatives neutralise nearly 500 pests worldwide, including insects, mites, ticks, and nematodes, by affecting their behaviour and physiology. Neem does not normally kill pests right away, rather it repels them and affects their growth. As neem products are cheap and non-toxic to higher animals and most beneficial insects, they are well-suited for pest control in rural areas.
- Besides its use in traditional Indian medicine, the neem tree is of great importance for its anti-desertification properties and possibly as a good carbon dioxide sink.
- Practitioners of traditional Indian medicine recommend that patients suffering from chicken pox sleep on neem leaves.
- Neem gum is used as a bulking agent and for the preparation of special purpose food (for diabetics).
- Aqueous extracts of neem leaves have demonstrated significant antidiabetic potential.
- Traditionally, slender neem branches were chewed in order to clean one's teeth. Neem twigs are still collected and sold in markets for this use, and in India one often sees youngsters in the streets chewing on neem twigs.
- A decoction prepared from neem roots is ingested to relieve fever in traditional Indian medicine.
- Neem leaf paste is applied to the skin to treat acne, and in a similar vein is used for measles and chicken pox sufferers.
- Neem blossoms are used in Andhra Pradesh, Tamil Nadu and Karnataka to prepare Ugadi pachhadi. "Bevina hoovina gojju" (a type of curry prepared with neem blossoms) is common in Karnataka throughout the year. Dried blossoms are used when fresh blossoms are not available. In Tamilnadu, a rasam (veppam poo rasam) made with neem blossoms is a culinary speciality.
- A mixture of neem flowers and bella (jaggery or unrefined brown sugar) is prepared and offered to friends and relatives, symbolic of sweet and bitter events in the upcoming new year.
Uses in pest and disease control
Neem is deemed very effective in the treatment of scabies, although only preliminary scientific proof, which still has to be corroborated, exists, and is recommended for those who are sensitive to permethrin, a known insecticide which might be an irritant. Also, the scabies mite has yet to become resistant to neem, so in persistent cases neem has been shown to be very effective. There is also anecdotal evidence of its effectiveness in treating infestations of head lice in humans. A tea made of boiled neem leaves, sometimes combined with other herbs such as ginger, can be ingested to fight intestinal worms.The oil is also used in sprays against fleas for cats and dogs.
As a vegetable
The tender shoots and flowers of the neem tree are eaten as a vegetable in India. Neem flowers are very popular for their use in Ugadi Pachhadi (soup-like pickle), which is made on Ugadi day in the South Indian States of Andhra Pradesh, Tamilnadu and Karnataka. A souplike dish called Veppampoo Rasam (Tamil) (translated as "neem flower rasam") made of the flower of neem is prepared in Tamil Nadu.Neem is also used in parts of mainland Southeast Asia, particularly in Cambodia, Laos (where it is called kadao), Thailand (where it is known as sadao or sdao), Myanmar (where it is known as tamar) and Vietnam (where it is known as sầu đâu and is used to cook the salad: gỏi sầu đâu). Even lightly cooked, the flavour is quite bitter and thus the food is not enjoyed by all inhabitants of these nations, though it is believed to be good for one's health. Neem Gum is a rich source of protein. In Myanmar, young neem leaves and flower buds are boiled with tamarind fruit to soften its bitterness and eaten as a vegetable. Pickled neem leaves are also eaten with tomato and fish paste sauce in Myanmar.
Association with Hindu festivals in India
- In the eastern coastal state of Orissa the famous Jagannath temple idols are made up of Neem heart wood along with some other essential oils and powders.
Patent Controversy
In 1995, the European Patent Office (EPO) granted a patent on an anti-fungal product, derived from neem, to the US Department of Agriculture and multinational W. R. Grace and Company. The Indian government challenged the patent when it was granted, claiming that the process for which the patent had been granted had actually been in use in India for over 2,000 years. In 2000, the EPO ruled in India's favour but the US multinational mounted an appeal claiming that prior art about the product had never been published in a scientific journal. On 8 March 2005, that appeal was lost and the EPO revoked the Neem patent rights keeping the tree free of these patent restrictions.Gallery
 Squirrel live on Neem tree Chennai, India. |  Flowers in Hyderabad, India. |  Trunk |  Animals under a Neem tree in a rural Punjabi home |
 |  A Neem tree with Spring blossoms |  Flowers in, India. |  Flowers in , India. |
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