PHYTOCHEMICAL INVESTIGATION AND ANTIMICROBIAL ACTIVITIES OF CRUDE EXTRACTS OF LEAVES, STEM BARK AND ROOT BARK OF SENNA DIDYMOBOTRYA

Abstract

enna didymobotrya plant is known for its value in traditional medicine, It is locally known as “muka ajoftu” which is traditionally used for the treatment of various human ailments in our country. The present study was carried out to analyze the phytochemical constituents, chemical composition and antimicrobial activities of Senna didymobotrya leaf, stem bark and root bark collected from Eastern Hararghe Zone, Haramaya (Damota). The plant parts were sequentially extracted with nhexane, chloroform: methanol (1:1) and methanol solvent system by Soxhlet method to determine the successive extractive values and GC-MS analysis, to investigate their chemical composition. The crude extracts were subjected to phytochemical test which showed the presence of alkaloids, flavonoids, terpenoids, tannins, saponins and phenols. The n-hexane extract of the plant were esterified and a total of 25 chemical compounds were found in S. didymobotrya (leaf, stem bark and root bark parts). The major components were 9,12-octadecadienoic acid, methyl ester (47.2% in stem bark, 43.12% in root bark) followed by hexadecanoic acid, methyl ester(29.65% stem bark, 27.66% leaf, and 23.78% root bark), 9,12,15-octadecatrienoic acid, meth yl ester, (Z, Z, Z) (22.41% leaf, 4.71% Stem bark and 9.34% in root bark), 9,12- octadecadienoic acid (Z, Z)-, methyl ester (12.27%) and 1,3-propanediamine, Nmethyl-(11.21%) in extracts of leaf). The antimicrobial activity of the crude extracts were tested against four bacterial species; two Gram positive bacteria (S. aureus and S. agalactia) and two Gram negative bacteria, (E. coli and S. typhi) and two fungal species (A. Niger and F. verticilliodes) using paper disc diffusion method. The maximum antibacterial activity was shown by methanol crude extract against S. typhi having inhibition diameter of 26.5mm and maximum antifungal activity was observed by chloroform:methanol (1:1) crude extract against A. Niger (26.7mm). Therefore, nhexane chloroform:methanol (1:1) and methanol extract of leaf, stem bark and root bark of S. didymobotrya might be a potential source of antimicrobial compounds.