Antibacterial and phytochemical evaluation of methanolic leaf extracts from Acacia ataxacantha and Piliostigma thonningii

Abstract

Bacterial infections are among the leading mortality causes despite the use of modern antibiotics. Medicinal plants can provide alternative antimicrobial products. Acacia ataxacantha and Piliostigma thonningii are indigenous plants used to treat various infections, whose activities lack scientific backing. This study investigated the antibacterial activities of A. ataxacantha and P. thonningii against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhi and Shigella flexneri. Minimum inhibition and bactericidal concentrations were evaluated. P. thonningii and A. ataxacantha inhibited the studied pathogens’ growth producing mean inhibition zones of 6.33±0.33 to 19.00±0.58 mm and 6.33±0.33 to 17.00±0.58 mm respectively. The extracts’ antibacterial activities were more pronounced against the Gram positive than the Gram negative bacteria. The extracts were bactericidal against S. aureus, B. subtilis, S. typhi and S. flexneri while they were bacteriostatic against E. coli. These plants can therefore be alternatives for managing bacterial infections after ascertaining their effective doses and safety profiles.