In vitro evaluation of the antifungal activity of Sclerocarya birrea extracts against pathogenic yeasts

The antifungal activity of Sclerocarya birrea which is used in South African traditional medicine for the treatment of skin diseases was evaluated against three yeasts; Candida parapsilosis, Cryptococcus albidus and Rhodoturula mucilaginosa. Barks of S. birrea were extracted with hexane, dichloromethane (DCM), chloroform, ethyl acetate, acetone, methanol and ethanol and tested against these three yeasts. The antifungal assay was performed by the microdilution technique and bioautography. Thin layer chromatography was used to analyze the phytocompounds of the extracts as well as to assay the plant for antioxidant compounds. More compounds with antioxidant activity were observed in polar separation system, ethyl  cetate:methanol:water (EMW). All test organisms were resistant against all non-polar extracts. Acetone, ethanol and methanol S. birrea extracts had average MIC values of 0.39, 0.22 and 0.27 mg/ml, respectively. C. albidus was the most sensitive organism with an average MIC value of 0.17 mg/ml. Average total activity was highest for methanol (387 ml/g) followed by ethanol (363 ml/g) and acetone (299 ml/g) bark extracts. Acetone and methanolic bark extracts were more active in EMW system at Rf values of 0.07, 0.32 and 0.70 against C. parapsilosis. The results showed that the plant could be further explored for possible antifungal agents and provides preliminary scientific validation of the traditional medicinal use of this plant.