In Vitro Antimicrobial Activity of Crude Leaf Extracts from Aloe secundiflora, Bulbine frutescens, Vernonia lasiopus and Tagetes minuta against Salmonella typhi

Abstract

Four medicinal plants leaves were investigated to evaluate their antibacterial potential of the methanol extracts against Salmonella typhi by disc diffusion method. The methanol extract from Aloe secundiflora showed strong antibacterial activity against a clinical isolate of Salmonella typhi at low concentrations (5.5 mg/ml) as compared to Bulbine frutescens extract (8.8 mg/ml). The minimum inhibitory concentration ranged from 5 mg/ml - 9 mg/ml whereas the maximum bactericidal concentration range from 7 mg/ml - 11 mg/ml. The standard antibiotic used was ciprofloxacin (15 μg/ml) was used as a positive control while dimethyl sulphoxide and distilled water were used as the negative control. The extracts were preliminary screened for the presence of secondary metabolites to determine the presence of flavonoids, alkaloids, tannins and saponins. The results supported the use of the medicinal plants in the treatment of infections caused by Salmonella typhi.