Evaluation of Anti-Salmonellal Activities of the Aqueous andEthanolic Extracts of Selected Nigerian Medicinal Plants used Locally for Typhoid Fever Treatment

Abstract

Background: Many Nigerian medicinal plants are used locally for the treatment of typhoid fever by traditional medicine practitioners and herb sellers. However, the laboratory evaluation of the efficacy and anti-salmonellal activities of such plants are sparse. Objective: The objective of this study was to evaluate the anti-salmonellal activities of six Nigerian medicinal plants that are used locally for the treatment of typhoid fever. Method: The ethanolic and aqueous extracts of six medicinal plants, viz. Ficus exasperata, Lannea egregia, Lophira alata, Mangifera indica, Momordica charantia and Morinda lucida were screened for in-vitro activities against Salmonella typhi. Kirby-bauer disc diffusion method was used to determine the inhibitory property of the extracts at concentrations of 12.5, 25, 50 and 100 mg/ml. The plants were also screened for phytochemical components using standard methods. Results: All the plant extracts, except the aqueous extracts of Lophira alata, Morinda lucida and ethanolic extract of Momordica charantia, exhibited significant anti-salmonellal activities at concentration of 100 mg/ml with the aqueous extract of Mangifera indica showing the highest anti-salmonellal activity producing zone of inhibition of 16.67±0.67 mm followed by ethanolic extracts of Morinda lucida (12.67±1.20 mm), Lannea egregia (11.33±0.33 mm), Ficus exasperata (11.00±0.00 mm), Lophira alata (10.33±0.33 mm) and Momordica charantia (aqueous extract) (8.33±4.26 mm). However, all the extracts were less active than amoxicillin (18.67±0.67 mm) and ciprofloxacin (38.67±0.33 mm). Conclusion: Mangifera indica, Morinda lucida, Momordica charantia, Lannea egregia, Lophira alata and Ficus exasperata possess anti-salmonellal activities. This justifies their traditional use for the treatment of typhoid fever and their active constituents may serve as leads in the production of new anti-typhoid drugs.