CHEMICAL CONSTITUENTS FROM METHANOLIC STEM BARK EXTRACTS OF Piliostigma thonningii BELONGING TO FABACEAE.

Abstract

Piliostigma thonningii (Schum.) Milne-Redh is a legume plant belonging to the Fabaceae family. It is locally used in the treatment of various human diseases like microbial infections, dysentery, fever, skin diseases, snake bites, infections, respiratory ailments and hookworm. The presence of various phytochemicals in this plant may be responsible for the biological activities of this plant, hence the major objective of this work is to isolate and characterize the phytochemical constituents of the stem bark of P. thonningii. The methanol crude extract obtained was partitioned with ethyl acetate, butanol and distilled water and the resulting fractions were purified over silica gel column chromatography to isolate the respective pure compounds. The isolated compounds were structurally elucidated by means of 1H, 13C, DEPT 135, HSQC and HMBC-NMR spectroscopic technique and compared with published data. The result of phytochemical investigation of P. thonningii methanolic stem bark extract led to isolation of five compounds: Garcinielliptone Q (1), (20S, 24R)-Epoxydammarane-3β, 25-diol (2), Protocatechuic acid (3), Epicatechin (4) and β-Sitosterol (5). Garcinielliptone Q (1) was isolated for the first time from this plant. The compounds isolated could be part of the phytochemicals responsible for its various biological activities.