CHEMICAL CONSTITUENTS FROM THE ALSTONIA SCHOLARIS STEM BARK, ECLIPTA PROSTRATA AERIAL PARTS AND MORUS ALBA STEM BARK
Mohammed Ali*, Shahnaz Sultana and Showkat Rassol Mir
Alstonia scholaris (L.) R. Br. (family Apocynaceae) is a large, evergreen, tropical tree and its stem bark is used to treat abdominal and respiratory complaints, fevers, gonorrhoea, headache, hypertension, influenza, irregular menstruation, malaria, skin diseases, snakebites and urticaria. Eclipta prostrata L. (family Asteraceae) is a small, erect, annual herb and used to relieve acidity, allergy, alopecia, asthma, baldness, cuts, dandruff, gingivitis, hypertension, insomnia, jaundice, leucoderma, lice infection, menorrhagia, piles, pimples, pneumonia, ringworm, scorpion sting, skin diseases, snake bites, sores, wounds and wrinkles. Morus alba L. (family Moraceae) is a fast-growing, deciduous, evergreen tree and its bark is taken orally to expel tape worms and to cure toothache. This research work was undertaken to characterize structures of chemical constituents isolated from these plants. The air-dried plant materials were exhaustively extracted with methanol individually in a Soxhlet apparatus. The concentrated methanol extracts were adsorbed on silica gel for column and chromatographed over silica gel columns separately. Each column was eluted with petroleum ether, chloroform and methanol successively to isolate the phytoconstituents. Phytochemical investigation of the stem bark of A. scholaris afforded two lupene-type pentacyclic triterpenoids identified as lup-5, 12, 20(29)-trien- 3β-acetoxy-22α-ol (alstrinine acetate, 1) and lup-5, 12, 20(29)-trien- 3β, 22α-diol (alstrinine, 2) along with 3-epi-stigmasterol (3), β-sitosterol (4) and β-sitosterol-3β-O-glucoside (5). The aerial parts of E. prostrata furnished a new tetracyclic triterpenoid characterized as lanost-5, 24-dien-7β-ol -18, 21-olide -3β-olyl palmitate (6). The stem bark of M. alba yielded two known pentacyclic triterpenoids marked as α-amyrin acetate (urs-12-en-3β-yl acetate, 7) and 3-epi-betulinic acid (8). The structures of these phytoconstituents have been established on the basis of spectral data analysis and chemical reactions.
Keywords: Alstonia scholaris bark, Eclipta prostrata aerial parts, Morus alba bark, phytoconstituents, isolation, characterization.
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