Chemical composition and antimicrobial activity of various extracts of O. gratissimum L. from Guilan, Iran

Abstract

The in vitro antimicrobial activities of crude ethanol, methanol and water extracts of the stem bark of O. gratissimumwere investigated. The extracts exhibited 52 M. R. M. Khoshkholgh Pahlaviani et al antimicrobial activities with zones of inhibition ranging from 10 to 20, 7 to 14 and 2 to 7mm for methanol, ethanol and water extracts respectively. The minimum inhibitory concentration (MIC) of the methanol extract was between 0.5 and 10 mgml -1 while that of ethanol extract ranged from 0.5 to 20 mgml -1 ,while MIC and MBC of streptomycin (Control strain) ranged between 0.065 and 0.5 mgml-1 for all tested bacteria. The minimum bactericidal concentration (MBC) for methanol extract ranged between 2.0 and 12.50 mgml-1, while that of ethanol ranged from 2.0 to 20 mgml-1. Again all the extracts exhibited appreciable activity against all the fungal species investigated. The zones of inhibition exhibited by the extracts against the test fungal species ranged between 2 and 9 for water, ethanol and methanol extracts respectively. Phytochemical screening revealed the presence of saponin, steroids, tannins, glycosides, alkaloids and flavonoids in the extracts. The ability of the crude stem extracts of O. gratissimum to inhibit the growth of bacteria is an indication of its broad spectrum antimicrobial potential which may be employed in the management of microbial infections.