in vitro lipid peroxidation inhibitory and antimicrobial activity of phyllanthus niruri (euphorbiaceae) extract

the present work was designed to evaluate the in vitro lipid peroxidation inhibitory and antimicrobial activities of the methanol extract of phyllanthus niruri (mepn) (family:   euphorbiaceae) .   lipid peroxidation was measured by the optical density of the prepared solutions (10-320 µg/ml) and then the percent inhibition was calculated. ascorbate/feso 4 -induced peroxidation was inhibited by standard antioxidants such as l-ascorbic acid, quercetin and mepn.   moreover, the percent inhibition of the methanol extract was increased in a concentration-dependent manner. ic 50 value for the mepn, l-ascorbic acid and quercetin for lipid peroxidation was found to be 62. 5 µg/ml, 41 µg/ml and 19.75 µg/ml respectively. the antimicrobial activity of mepn was determined by disc diffusion method with various gram positive and gram-negative microorganisms.   the mepn showed strong antimicrobial activity against bacillus pumillus 8241, bacillus cereus , escherichia coli 54b and vibrae cholera at a concentration of 750 m g/ml/disc. however, its activity against staphylococcus aureus ml 152 and vibrae cholera 14035 was less significant. the antimicrobial activity of the extract was compared with the standard drug, chloramphenicol at a concentration of 10 m g/ml/disc. the results obtained in the present investigation clearly suggest that mepn can be a potential source of natural antioxidant and antimicrobial agent.