Phytochemical screening and antibacterial activity of dried pods of Prosopis Africana

Evolving resistant microbial strains have posed a great challenge on antibacterial chemotherapy in recent times. Search for novel antimicrobial agents has therefore remained a highly prospective area of research, especially those of plant origin. To this end, Prosopis africana pod used in West Africa in traditional medicine was evaluated for phytochemical constituents using standard procedures. Antibacterial activity was determined using the disc diffusion method of National Committee for Clinical Laboratory Standards. Discs were impregnated with 0.10 and 0.20 mg/ml of the aqueous and ethanolic extracts. Test organisms were wild strains of Streptococcus pyogenes, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis and Escherichia coli sourced from a medical hospital’s microbiology laboratory. 0.20 mg/ml ethanolic fraction exhibited highest activity against E. coli and S. aureus with mean zone of inhibition of 18.2 and 17.6 mm respectively. The 0.20 mg/ml aqueous fraction was more active against S. aureus (16.40 mm) and P. mirabilis (14.80 mm). The least zone of inhibition was 10.10 mm. Phytochemical screening of the extracts showed the presence of terpenoids, saponnins, glycosides, alkaloids and tannins, to which the observed antibacterial activity could be attributed. The extracts are potent in vitro antibacterial preparations. With this prospect, this can be employed as starting material for the development of a novel antimicrobial agent. Key words: Phytochemicals, antibacterial activity, Prosopis africana pod, ethanolic extracts, aqueous extracts.