Abstract

Phytochemical screening of the Gmelina arborea reveals the presence of carbohydrates, alkaloids, saponins, tannins, anthraquinones and cardiac glycosides. The presence of these bioactive compounds in plants is linked to biological activity. Determination of antimicrobial activity using the agar diffusion method showed that the crude extracts of the leave and stembark of the plant inhibited the growth of such recalcitrant pathogenic Escherichia coli, Klebsiella pneumonieae, Proteus mirabilis, Shigella dysenteriea and Salmonella typhi that frequently show above average resistance, the extent of which depended on the solvent and organism. Activity of the extracts was consistently less than the conventional antibiotic, tetracycline. The effectiveness of the extracts was more in the acidic than in alkaline conditions and also increased with increase in temperature. Results provided the scientific bases for the folkloric application of G. arborea as a medicinal plant and ways the plant can be used as source for newer antibiotic substances for the possible control of dysentery, diarrhea, typhoid fever and wound infections associated with these bacteria.

Key words: Gmelina arborea, phytochemicals, resistance, extracts, antibiotics, pathogenic, traditional medicine.