Abstract:
An emerging of antibiotic resistance strains of bacteria brings most serious public health
problems. It is therefore, important to look for more effective, safer and less toxic alternative
options of treatment. The aim of the present study was to investigate antibacterial activities of
Harrisonia abyssinica, Leucas spp., Solanum incanum, Hydnora johanis, Croton macrostachyus
and Ocimum lamiifolium against Escherichia coli, Salmonella typhi, Staphylococcus aureus and
Enterococcus feacalis. Disc diffusion method for antimicrobial activity test and broth dilution
method for minimum inhibitory concentration (MIC) determination have been followed. The
result revealed that ethanol and ethyl acetate extracts of the plants had showed better
antibacterial activity than aqueous, acetone and chloroform extracts against E. coli, S. typhi, S.
aureus and E. feacalis. Relatively, the ethanol extract of H. johanis and H. abyssinica; the ethyl
acetate extract of H. abyssinica and S. incanum; and the acetone extract of S. incanum had
showed good antimicrobial activity on all tested bacteria. The ethyl acetate and acetone extract
of O. lamiifolium and the ethyl acetate extract of C. macrostachyus also demonstrated good
antimicrobial activity on S. aureus. Compared with standard antibiotics; most active crude
extracts were showed comparative antimicrobial effect as do standard antibiotics (penicillin,
ampicillin and tetracycline). The extract demonstrated least MIC value of 1.56 mg/ml with
ethanol extract of S. incanum and Leucas spp. against S. aureus, with ethyl acetate extract of S.
incanum against S. typhi and with acetone extract of H. johanis against E. coli and S. typhi.
Phytochemicals such as steroids, tannins, saponin, flavonoids, alkaloids and terpenoids were
identified compounds in most tested plants. Over all, this study proves the scientific basis for the
traditional use of the plants as antimicrobial agent for the treatment of infections caused by E.
coli, S. typhi, S. aureus and E. feacalis.
