Assessment of the Antimicrobial Potency of Leaf Extracts from Vitex Nugundo and Gloriosa Superba

An increase in the number of antibiotic resistant strains makes the discovery of new therapeutic agents critically important. During present study antimicrobial effects of the leaf extracts of Vitex nugundo (VN) and Gloriosa superba (GS) in combination with chloramphenicol, on Escherichia coli, Salmonella typhi, Staphlococcus aureus and Candida albicans was investigated. For this purpose, the dilution sensitivity and disc diffusion techniques were respectively applied in determining minimum inhibitory concentration (MIC) of the plant extracts, and the sensitivities of the organisms to the plant extracts and their combinations with chloramphenicol. V. nugundo and G. superba showed very high antimicrobial activity against all the test organisms. In combination, the effect of VN on E. coli and S. typhi was completely antagonized by that of GS whereas additive effect on S. aureus and C. albicans was observed, indicating that the combination of VN and GS might be effective against gram positive pathogenic organisms. The combination of either plant extract with chloramphenicol produced synergistic effect on only C. albicans. The smaller MIC of GS indicated greater effectivity than VN. It is concluded that the additive effect produced by the combination of the two plant extracts, and the synergic effect from the combination of any of the extracts with chloramphenicol, offer alternative therapy to gram positive bacterial infections and candidiasis respectively.