PHYTOCHEMICAL INVESTIGATION AND EVALUATION OF ANTIMICROBIAL ACTIVITIES OF STEM BARK OF Myrica salicifolia

Abstract

Myrica salicifolia is one of the 150 Genus Myrica species growing East and Central Africa. The present study was carried and to investigate phytochmemicals and evaluate antimicrobial activities on the stem bark of Myrica salicifolia because, the plant bark is used for traditional medicine for the treatment of toothache, headache and stomachache in the place where the sample was collected. The stem bark of the plant was sequentially extracted with: petroleum ether, chloroform and chloroform/methanol (1:1 ratio) for 8 h in Soxhlet apparatus. Phytochemical screenings test of Myrica salicifolia stem bark extracts were performed on: petroleum ether, chloroform and chloroform/methanol (1:1 ratio) crude extracts. The petroleum ether extract of the plant showed the presence of alkaloid, tannis, saponins, flavonoid, protein, triterpenoid and absence of terpenoids. The chloroform crude extract of the plant showed the presence of alkaloid, tannis, flavonoid, protein, triterpenoid and absence of saponins and terpenod. The chloroform/methanol (1:1 ratio) crude extract of the plant showed the presence of tannis, flavonoid, triterpenoid and absence of alkaloid, tannis, saponins and protein. Volatile oil of the plant was extracted using a Clevenger apparatus and its constituents were determined by GC-MS. GC-MS profile showed the presence of 14 compounds among which the major constituents of stem bark oil were hexadecanoic acid methyl ester (29.40%), 9-octadecenoic acids (z) methyl ester (28.64%), methyl tetradecanoa (10.7%), methyl stearate (8.08%), methyl 10-trans, 12-cis-octadecadienoate (4.85%) and cyanoacetyl urea (4.10%). The volatile oil, crude extracts, isolated pure compounds and fractions of the stem bark were tested in vitro for their antimicrobial activity by disk diffusion method. The highest activity was exhibited by volatile oil, CHCl3/MeOH (1:1 ratio) and petroleum ether extract against S. flexneri, E.coli and S. agalactiae with an inhibition diameter of 21.66, 17.66 and 18.00 mm, respectively. The maximum antifungal activity was shown by isolated pure compound against A. niger and F. oxysporiu with zone of 23.33 and 14.25 mm, respectively. The pure compound MS-3 isolated from petroleum ether extract with solvent ratio of petroleum ether: ethyl acetate (8.5:1.5). The structures of these compounds were established by use of UV-VIS, IR and NMR spectral data and by comparing with literature reports as a cyclic diarylheptanoids. Isolated pure compounds exhibited medium antimicrobial activity against E. coli, these compounds showed potential as antimicrobial agents and might be used to improve therapeutic efficiency to overcome, rising bacterial and fungal resistance of existing drugs.