Azadirachta indica
Content
Description
Tree to 16 m; bole to 60 cm diam.
Bark red-brown or greyish, fissured and flaking in old trees; inner bark red-brown with colourless, sticky foetid sap; sapwood whitish.
Leaves 15–35 cm, imparipinnate or paripinnate with terminal spike, 4–7-jugate, red when young, garlic-scented when damaged; petiole c. 3–7 cm, c. 1.5 mm diam., subglabrous, base weakly swollen.
Petals linear spathulate, 4–6 mm long, white, ± pubescent on both sur- faces.
Staminal tube glabrous to sparsely pubescent, 10-ribbed, margin with 10 rounded or somewhat laciniate lobes; anthers 10, c. 0.8 mm long, narrowly ellipsoid, basifixed, weakly exserted.
Ovary glabrous to finely pubescent.
Distribution
Asia-Tropical: Lesser Sunda Is. (Bali present); Malaya (Peninsular Malaysia present); Sumatera (Sumatera present), Burma present, East Java present, Lombok present, Sumbawa present, Tropical Africa present, West Java present, tropical Asia present
Probably native in Burma but widely and long cultivated in tropical Asia and Africa, where it has become extensively naturalized. In Malesia planted in Sumatra, the Malay Peninsula, and West Java, also in East Java, and the Lesser Sunda Islands (Bali, Lombok, Sumbawa), where it is, like Tamarindus indica L. (Leguminosae), so completely naturalized in the greatly modified seasonal forest areas there as to appear native.tropical Africa
Uses
See also the paragraph on Phytochemistry, p. 8. Held sacred by the Hindus, the neem is potentially one of the most important of all tropical seasonal forest trees, having proved to be very adaptable and able to withstand arid conditions. It can be grown in impoverished soil and is a fastgrowing source of fuel wood .
The form grown in West Africa is ignored by stock and is therefore readily establish- ed. Some forms in Asia, however, are used as fodder and in the Malay Peninsula the young leaves and flowers are boiled and eaten with rice (Corner, l.c.). In Central Amer- ica, it is now widely planted and recent trials have shown it to grow rapidly and produce fine timber which makes a good substitute for Swietenia mahogany . It is the most important plantation species in northern Nigeria and is used as poles or for fuel. It coppices well and the timber has a very high calorific value. Coppice shoots may reach 10 m height in two years. The wood is tougher than teak and resists decay. It is also widely planted as a windbreak, shade and avenue tree, the world’s biggest plantation being of 50,000 trees in the plains of Saudi Arabia, plant- ed to shade the two million or so Muslim pilgrims camping there annually for ‘Haj’ rites . It is a soil ameliorant and is potential- ly a source of many valuable by-products (Radwanski & Wickens, l.c.). It has been an ingredient of soaps, toothpaste and lotions in commerce for some decades (Corner, l.c.).
The seeds contain some 40% oil by weight and this bitter material has been used in lamps and as a lubricant and has potential as a fuel-source, the mesocarp being a prom- ising substrate for the production of methane gas.
Neem cake is an excellent fertilizer and the leaves and twigs are used as a mulch in Asia.
The bark produces a valuable gum and tannin worth exploiting. The pressed leaves have long been put in books to ward off insects, the repellent being the limonoid, aza- dirachtin, which is in the seeds as well as the leaves; house-sparrows in India incor- porate leaves into their nests, perhaps reducing parasite loads. Azadirachtin is absorbed by plants and acts as a systemic insecticide so efficient that Japanese beetles and other insects, even including the desert locust, will starve rather than eat plants treated with it. It has been alleged that the substance is repellent to nematodes as well (Ruskin, l.c.). Of the many limonoids known from the tree, deacetylaxadirachnol (salannin) is as potent as azadirachtin in inhibiting ecdysis in tobacco budworm . Neem seed powder with carbofuran greatly reduces leaf-hoppers and rice tungro) virus in rice . Reduction in the incidence of phloem-specific tungro viruses in neem-treated plants is attributed to a shift in insect-feeding from phloem to xylem vessels .
Neem is alleged to contain anti-culicid factors and may be effective in controlling the spread of malaria. Under the Sanskrit name nimba it is mentioned in the Ayurvedae (Systema Medicinae) of Susruta, one of the most ancient of the Hindu medical writings. The first European account was published by Garcia d’Orta, physician to the Portuguese Viceroy at Goa in India, in 1563. The leaves, bark and seed oil have medicinal proper- ties summarized by , and have been used in the treatment of a wide range of ailments, including malaria, eczema, dysentery and ulcers, but is particularly effective as a parasiticide for skin diseases such as scabies. Nimbidin, a substance isolated from the seed oil, has been found to be an efficient anti-inflamma- tory agent in artificially induced arthritis and oedema in rats , while an aqueous extract of the bark has been shown to increase lymphocyte function such that production of MIF, a lymphokine, is increased, which may account for the generally stimulating and skin-healing properties long observed . Some of the triterpenoids have antibacterial activity . Neem oil also has significant post-coital contraceptive action .
The form grown in West Africa is ignored by stock and is therefore readily establish- ed. Some forms in Asia, however, are used as fodder and in the Malay Peninsula the young leaves and flowers are boiled and eaten with rice (Corner, l.c.). In Central Amer- ica, it is now widely planted and recent trials have shown it to grow rapidly and produce fine timber which makes a good substitute for Swietenia mahogany . It is the most important plantation species in northern Nigeria and is used as poles or for fuel. It coppices well and the timber has a very high calorific value. Coppice shoots may reach 10 m height in two years. The wood is tougher than teak and resists decay. It is also widely planted as a windbreak, shade and avenue tree, the world’s biggest plantation being of 50,000 trees in the plains of Saudi Arabia, plant- ed to shade the two million or so Muslim pilgrims camping there annually for ‘Haj’ rites . It is a soil ameliorant and is potential- ly a source of many valuable by-products (Radwanski & Wickens, l.c.). It has been an ingredient of soaps, toothpaste and lotions in commerce for some decades (Corner, l.c.).
The seeds contain some 40% oil by weight and this bitter material has been used in lamps and as a lubricant and has potential as a fuel-source, the mesocarp being a prom- ising substrate for the production of methane gas.
Neem cake is an excellent fertilizer and the leaves and twigs are used as a mulch in Asia.
The bark produces a valuable gum and tannin worth exploiting. The pressed leaves have long been put in books to ward off insects, the repellent being the limonoid, aza- dirachtin, which is in the seeds as well as the leaves; house-sparrows in India incor- porate leaves into their nests, perhaps reducing parasite loads. Azadirachtin is absorbed by plants and acts as a systemic insecticide so efficient that Japanese beetles and other insects, even including the desert locust, will starve rather than eat plants treated with it. It has been alleged that the substance is repellent to nematodes as well (Ruskin, l.c.). Of the many limonoids known from the tree, deacetylaxadirachnol (salannin) is as potent as azadirachtin in inhibiting ecdysis in tobacco budworm . Neem seed powder with carbofuran greatly reduces leaf-hoppers and rice tungro) virus in rice . Reduction in the incidence of phloem-specific tungro viruses in neem-treated plants is attributed to a shift in insect-feeding from phloem to xylem vessels .
Neem is alleged to contain anti-culicid factors and may be effective in controlling the spread of malaria. Under the Sanskrit name nimba it is mentioned in the Ayurvedae (Systema Medicinae) of Susruta, one of the most ancient of the Hindu medical writings. The first European account was published by Garcia d’Orta, physician to the Portuguese Viceroy at Goa in India, in 1563. The leaves, bark and seed oil have medicinal proper- ties summarized by , and have been used in the treatment of a wide range of ailments, including malaria, eczema, dysentery and ulcers, but is particularly effective as a parasiticide for skin diseases such as scabies. Nimbidin, a substance isolated from the seed oil, has been found to be an efficient anti-inflamma- tory agent in artificially induced arthritis and oedema in rats , while an aqueous extract of the bark has been shown to increase lymphocyte function such that production of MIF, a lymphokine, is increased, which may account for the generally stimulating and skin-healing properties long observed . Some of the triterpenoids have antibacterial activity . Neem oil also has significant post-coital contraceptive action .
Notes
Gametogenesis and embryogenesis are discussed by
Neem can be an aggressively invasive tree and it needs careful control to prevent its swamping other crops (Ruskin, l.c.).
Citation
Koord. 1913 – In: Atlas. t. 164
Valeton 1904: p. 66. – In: Hochr., Pl. Bogor. Ex- sicc. incl. var. minor Valeton & var. siamensis Valeton
Tewari 1992: Monogr. Neem
C.DC. 1878: p. 459. – In: DC, Monogr. Phan. 1. f. 10
Miq. 1859 – In: Fl. Ind. Bat. p 533
Griff. 1854 – In: Notul. p 500
T.D.Penn. 1975: p. 461. – In: Blumea. t. 4e
Miq. 1861: Fl. Ind. Bat. p 502
Harms 1896: p. 160. – In: Engl. & Prantl, Nat. Pflanzenfam. 3, 4. f. M–S
Ahmed & Grainge 1986 – In: Econ. Bot. p 201
Koord. & Valeton 1896 – In: Bijdr. Booms. Java. p 21
A. Juss. 1980: Firew. Crops. p 114
Backer 1907 – In: Fl. Batavia. p 270
Briq. 1935: p. 44. – In: Mém. Inst. Nat. Genev. incl. var. minor & var. siamensis
Vaughan 1970: Struct. Util. Oil Seeds: 155. t. 82 E-F
Prinsen Geerl. 1902: p. 8. – In: Teysmannia. cum tab.
Backer & Bakh.f. 1965 – In: Fl. Java. p 120
Corner 1976 – In: Seeds Dicots. 191.
Harms 1940 – In: Engl. & Prantl, Nat. Pflanzenfam., ed. 2, 19bl. t. 26, f. M–S
Valeton 1905: Cat. Bogor. Nov: 21, 110, 131. incl. var. minor & var. siamensis',
Miq. 1868 – In: Ann. Mus. Bot. Lugd.-Bat. p 5
Jacobs 1961 – In: Gard. Bull. Sing. p 74
K.Heyne 1950: Nutt. Pl. Indon., ed. 3. p 889
Hiern 1875 – In: Hook, f., Fl. Brit. India 1. p 544
DC 1824 – In: prodr. p 622
Koord. 1912 – In: Exk. Fl. Java. p 439
Backer 1911: Schoolfl. Java. p 202
Nicolson et al. 1988: Int. Hort. Malab. p 190
Blume 1825: Bijdr. p 161
Bisschop Grev. 1883: Pl. Ned. Ind. p 491
Ridley 1922 – In: Fl. Malay Penins. p 384
Radwanski & Wickens 1981 – In: Econ. Bot. p 398