ABSTRACT

The antibacterial activity of the alcohol extract of the stembark of Picralima nilida was

tested against Staphylococcus aureus ATCC 12600, Pseudonionas aeruginosa ATCC

10145, Bacillus sublilis ATCC. 6051, Escherichia coli ATCC 11775, Salmonella

kintambo 1-luman 1,13,23 mt: - and three clinical isolates. The antibacterial assay was by

both the agar-well diffusion and macro-broth dilution methods. Separation of the crude

extract by column chromatography yielded six fractions of which, all contained alkaloid

except F1 . The spectra of activity for the crude extract and active fractions was 50%

each, with no apparent activity recorded against the clinical isolates. Fractions F1and F5

exhibited no antibacterial activity. The control drug, Gentamicin had 62.5% spectrum of

activity. There was significant difference (p<O.05) in antibacterial activity between the

crude extract and its fractions, with F2exhibiting the highest antibacterial activity. The

MIC range for the crude was 25-50mg/ml; F2, 3.125-50mg/mi; F3, 1.563-50mg/mi and

F6, 3.125-50mg/mi. The combined activity of the fractions showed that the active

components might be antagonistic to one another. Both the MBC and kill-rate study

show that the partially purified fractions had higher bactericidal effect as compared to the

crude extract. The level of activity was the same (62.5%) for each of the root, stembark

and seed extracts. These results provide scientific justification for the use of locally

distilled alcohol, as solvent for most herbal preparations.