Azadirachta indica A Juss stem bark as an anti-leprosy source

Following the siddha system of Indian medicine the stem bark of Azadirachta indica A. Juss. was added as a constituent of an anti-leprosy drug SULAK along with parts of 21 plants. Results of pharmaco-phytochemical studies on the stem bark are presented. Pharmacognosical characters of the bark are studied with the following parameters: taxonomy, anatomy, and powder study based on conventional methods. Phytochemical characters are studied with the following parameters: estimation of sugar, protein, free amino acids, and oil based on standard methods; the geochemicals copper, ferrous, manganese, potassium, sodium, zinc, phosphorus and sulphur (atomic absorption spectrophotometer-AAs, Varian Techtron Model Spectra 20 BA); the active principles alkaloid, anthraquinone heteroside, cardiac glycoside, glycone, phenol, sterol, tannin, and triterpene physical constants and chemical identity of the bark with that of standard anti-leprosy agents like clofazimine, dapsone, and rifampicin (Indian pharmacopoel methods). The bark has high oil content (17.5 per cent); alanine, methionine, and phenylalnine are the free amino acids present in lesser amount. It is rich in ferrous (325 ppm) and sulphur (425.93 ppm), but copper is absent. Active principles like unsaturated sterols, triterpene, saponin, cardiac glycoside, 2-deoxy sugar, and phenol are determined. Among these phenols, unsaturated sterols, triterpenes, and saponin are rich. Maximum alkaloid precipitation is observed from water extractive. Ethanolic extractive gives rich tertiary alkaloid (0.070 mEq/100 g dry wt). Total solid and ash are 83 and 6.01 per cent respectively. Chemical identity comparison of bark with standard antileprosy agents reveals that the activity is equivalent to that of clofazimine (4.3 per cent), dapsone (8.1 per cent), and rifampicin (2.2 per cent).