In Vitro Antifungal Activities of Selected Medicinal Plants from Zimbabwe against Candida albicans and Candida krusei

Thirty-eight Zimbabwean medicinal plant extracts were investigated for in vitro antifungal activity against Candida albicans and Candida krusei. These plants are used for the traditional treatment of various ailments, including fungal infections. The ethanol extracts were tested for antifungal activity using the agar disc diffusion method. The minimum inhibition concentrations (MICs) were determined for plant extracts that showed high efficacy against the tested microorganisms using the broth dilution method. The minimum fungicidal concentration (MFC) assay was carried out to determine if the fungal growth could irreversibly be inhibited by these plant extracts. The ciprofloxacin accumulation assay was carried out to investigate if these plant extracts could inhibit the activity of active drug efflux pumps in both Candida species. Nineteen plant extracts, among the 38 investigated, showed significant antifungal activity. MIC values ranged from 0.08–0.63 mg/ml for both C. albicans and C. krusei. MFCs ranged from 0.31–2.5 mg/ml. Combretum zeyheri extract had the highest antifungal activity in all cases. Combretum zeyheri and Combretum molle extracts were the most potent drug efflux pump inhibitors. The extracts from these Combretum species showed the greatest antifungal activity by both inhibition of growth and inhibition of drug efflux in C. albicans and C. krusei. Combretum molle and Combretum zeyheri provide a phytopharmacological basis for the traditional use of plant extracts against fungal infections. _____________________________________________________________________________________________________________