Antimicrobial Effect of Phyllanthus amarus and Parquetina nigrescens on Salmonella typhi

Abstract

Phyllanthus amarus and Paraquetina nigrescens are economic plants grown
in West Africa for antimicrobial properties. Crude aqueous (hot and cold
water) and ethanolic extracts of the plants were investigated for antimicrobial activity against Salmonella typhi. The organism was collected from the University College Hospital, lbadan, Nigeria and was exposed to ten standard different antibiotics and also to crude extract of P. amarus and P. nigrescens. Agar cup diffusion method was employed fro the plants extracts while disk diffusion method for the standard antibiotics. Ethanolic extracts of P. amarus had the strongest activity against Salmonella typhi with 8.0mm zone of growth inbibition followed by hot water (4.7mm) and cold water (3.8mm). This was statistically significant at P= 0.05 when compared with hot and cold water extracts. Amongst the commercial antibioticis examined, ciprofloxacin had the highest zone of growth inhibition of 9.0mm; Oflxation (6.0mm) Amoxycillin, (4.0mm) while other antibiotics had on effect on test organism. Screening carried out on P. amarus and P. nigrescens using standard methods revealed the presence of saponins, alkaloids, tannins and cardiac glycosides. P. amarus possesses significant antimicrobial activity and confirms the justification by herbalists as extract used for treatment of typhoid fever. (Afr. J. Biomed. Res. 11: 215 - 219)

Key Words: P. amarus, P. nigrescens, antimicrobial activity, standard antibiotics, typhoid fever