Antimicrobial activity and phytochemical screening of stem bark extracts from Jatropha curcas (Linn)

The in vitro antimicrobial activity of crude ethanolic, methanolic and water extracts of the stem bark of Jatropha curcas were investigated. The extracts exhibited antimicrobial activities with zones of inhibition ranging from 5 to 12, 8 to 20 and 0 to 8 mm for ethanol, methanol and water extracts respectively. The minimum inhibitory concentration (MIC) of the ethanol extract was between 0.5 and 6.25 mgml -1 while that of methanol extract ranged from 0.5 to 10 mgml -1. The minimum bactericidal concentration (MBC) for ethanol extract ranged between 2.0 and 12.50 mgml -1 , while that of methanol 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 15 and 18, 15 and 20 and 5 and 10 mm for ethanol, methanol and water extracts respectively. Phytochemical screening revealed the presence of saponin, steroids, tannin, glycosides, alkaloids and flavonoids in the extracts. The ability of the crude stem extracts of J. curcas to inhibit the growth of bacteria and fungi is an indication of its broad spectrum antimicrobial potential which may be employed in the management of microbial infections.