Abstract

Jatropha curcas and Newboulda laevis are medicinal plants used for the treatment of ailments such as diarrhoea, dysentery, sexually transmitted diseases, jaundice and several other diseases caused by micro-organisms. The antibacterial activities of the leaves of the plants were assessed against a panel of selected bacterial pathogens. Methanolic leaf extracts of J. curcas and N. laevis exhibited antibacterial activity against eight of the thirteen tested bacterial isolates at a final concentration of 20 mg/ml. The zones of inhibition exhibited by J. curcas ranged between 12 and 17 mm while that of N. laevis varied between 10 and 23 mm. The minimum inhibitory concentration of J. curcas extract ranged between 0.625 and 10.00 mg/ml, while that of N. laevis extract varied between 0.313 and 10 mg/ml. The standard antibiotic – streptomycin had MIC values of between 0.0313 and 0.0625 mg/ml. Phytochemical compounds present in the extract of J. curcas include alkaloids, saponins, steroids and tannins, while those present in N. laevis extract includes alkaloids, flavonoids and tannins.

Key words: Jatropha curcas, Newbouldia laevis, antibacterial, phytochemicals.