Antibacterial and Antifungal Activities of Some Extracts and Fractions Mitracarpus scaber Zucc. (Rubiaceae)

Abstract

Objective: To evaluate in vitro the potential antibacterial and antifungal activities of two crude extracts (n-hexane and 80% MeOH) from Mitracarpus scaber (Zucc) (Rubiaceae) leaves and that of fractions from of the partion of the 80% MeOH extract aiming to locate active fractions. Materials and methods: The n-hexane and 80% MeOH extracts of M. scaber leaves were separately obtained by maceration followed by exhaustive percolation with corresponding solvent. They were dried in vaccuo and their antibacterial and antifungal activities evaluated in vitro by the dilution method against 21 clinical isolates including 13 bacteria, 3 dermatophytes and 2 yeasts. Results: The two extracts exhibited a pronounced antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus faecalis (minimal inhibitory concentration and minimal bactericidal concentration < 65 µg/ml) and antifungal activity against Candida albicans, Candida tropicalis and Trihchophyton rubrum (minimal inhibitory concentration and minimal fungicidal concentration < 65 µg/ml). Only the n-hexane extract exhibited a pronounced antimycotic activity against Aspergillus flavus, Microsporum canis and Trichophyton mentagrophytes (minimal inhibitory concentration and minimal fungicidal concentration < 65 µg/ml). Escherichia colis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Asperigillus niger were found to be resistant to the effect of these extracts (minimal inhibitory concentration and minimal bactericidal concentration or minimal fungicidal concentration > 500 µg/ml). Both activities found in the 80% MeOH extract were located in the diethylether fraction from its partition with minimal inhibitory concentration of 7.8 to 62.5 µg/ml and minimal bactericidal concentration of 15.7 to 62.5 µg/ ml for the antibacterial activity and, minimal inhibitory concentration of 7.8 to 31.25 µg/ml and minimal fungicidal concentration of 15.7 to 62.5 µg/ml for the antifungal activity against all cited microorganisms above. It was however ineffective against Proteus mirabilis and Pseudomonas aeruginosa (minimal inhibitory concentration and minimal bactericidal concentration > 500 µg/ml). Conclusion: Mitracarpus scaber leaf extracts possess a wide antibacterial and antifungal spectra of activity that can justify and support its traditional use as a remedy for the treatment of fungal and bacterial skin diseases.