Antifungal Activities of Some Nigerian Medicinal Plants against Non-dermatophyte Molds Isolated from Cases of Onychomycosis among Rice Farmers in Anambra State, Nigeria

Abstract

Aims: To investigate in vitro antifungal activities of methanol, hexane and cold water extracts of Cassia alata, Mitracarpus villosus and Lawsonia inermis against non-dermatophyte molds isolated from rice farmers with onychomycosis in Anambra State, Nigeria. Study Design: Examination of antifungal activity of medicinal plants among cross-section of farmers. Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University Awka. Anambra State, Nigeria between November 2009 and June 2011. Methodology: Clinical samples were collected from 135 rice farmers in Anambra State, Nigeria and identified. Dried leaves of C. alata, M. villosus and L. inermis were extracted by soxhlet using methanol and hexane as solvents. Cold water extraction was also carried out using fresh leaves. The extracts were tested against the isolated non-dermatophyte molds using disc diffusion method at varying concentrations (10mg, 20mg, 40mg, 80mg). Discs impregnated with 2% dimethylsulphoxide were used as negative control while those impregnated with 2mg/disc ketoconazole served as positive control. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MIC) of the crude extracts were assayed for against the test isolates. Results: The organisms recovered included Aspergillus terrus, Aspergillus sclerotiorum, Aspergillus flavus, Fusarium sp., Chrysosporium sp. and Scopulariopsis sp. The organisms were sensitive to all the methanol extracts of medicinal plants with minimum inhibitory concentration range of 10-40mg/disc except A. flavus which was inhibited only by L. inermis extract at concentration of 40mg/disc. The mean zone of inhibition produced ranged between 6.0mm and 14.2mm with C. alata extract showing the highest zone of inhibition (14.2mm) against Fusarium sp. The standard Ketoconazole range was 6.0-12.4mm diameter. Hexane extract of L. inermis inhibited all isolates at 20-40mg/disc concentration. A. flavus resisted hexane extracts of C. alata and M. villosus, while A. terrus resisted extract of M. villosus alone. All isolates except A. flavus were sensitive to cold water extract of L. inermis with diameter zone of inhibition range of 6.2-8.2mm. Methanol extracts of C. alata and L. inermis showed fungicidal actions against all test isolates at 10-40mg/disc range except for A. flavus. Conclusion: The various antifungal extracts showed inhibitory/fungicidal effect against the isolated non-dermatophyte molds which compared favorably with that of standard antifungal drug, ketoconazole. The plant leaves could serve as sources for development of new antifungal drugs.