Combined Effect of Crude Leaf Extracts of Selected Medicinal Plants against Selected Enteric Bacterial Pathogens and Candida albicans

Abstract

The main aim of the study was to determine the antimicrobial potency of the plant extracts from leaves of Aloe secundiflora, Bulbine frutescens, Tagetes minuta and Vernonia lasiopus when used in combinations. The extracts were used against Gram negative bacteria (Shigella flexineri, Salmonella typhi, Escherichia coli and Enterococcus faecalis), Gram positive bacteria (Staphylococcus aureus) and fungal pathogen Candida albicans by Kirby Bauer method. The combination were determined using the permutation formula of P=N! / (N-R)! Producing six combinations. The combining of the plant extracts from Bulbine frutescens and Vernonia lasiopus with the others showed improved antimicrobial activity especially against Escherichia coli. A decrease in antimicrobial activity was observed when all the plant extracts were used in combinations against Candida albicans. The standard antibiotics used were Ciprofloxacin (Gram negative bacteria), Vancomycin (Gram positive bacteria) and fluconazole against Candida albicans. The preliminary phytochemical screening of the extracts confirmed the presence of alkaloids, saponins, tannins and flavonoids. Our study revealed that, some of the plant extracts can be used in combination in improving their effectiveness in treating the diseases caused by the bacterial pathogens and fungus Candida albicans.