In vitro evaluation of the antifungal activity of extracts of Baillonella toxisperma (Pierre), a Sapotaceae, on the growth of some human pathogenic yeasts

Abstract

An ethnopharmacological survey concerning medicinal properties of Baillonella toxisperma (Pierre) was carried out by interview with the indigenous population of Dimako village situated in the East region of Cameroon. The result showed that the plant is implicated in the treatment of many infections among which is fungal infections. To confirm the antifungal property of B. toxisperma (Pierre), the barks and leaves of the plant were collected and serial extractions in water, hydro-ethanol mixture (3:7), ethanol, methanol and ethyl acetate were performed in vitro. One part of the hydro-ethanol (3:7) extract was degreased by mixing in water-hexane mixture (1:1). The extracts were then tested in vitro against Candida albicans, Candida parasilopsis, Candida sp. responsible for superficial, deep or systemic mycosis and against Cryptococcus neoformans responsible for sub-acute meningitis in immunodeficient individuals. The susceptibility of yeasts to plant extracts was evaluated using the wells diffusion method and yeasts growth inhibition parameters were evaluated according to the proposed National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 standard guidelines (2002). The minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) determined were between 0.93 and 30.0 mg/ml. The extracts were fungicidal on clinical yeasts tested with MFC/MIC ratio of 1 or 2. The hexane phase HT2 from the hydro-ethanol crude extract of the barks gave the best antifungal activity on C. neoformans, with a MIC of 0.93 mg/ml and a MFC of 1.87 mg/ml. This activity was similar to the one obtained with fluconazole. Phytochemical screening revealed the presence of polyphenols, phenols, tannins, flavonoids, steroids, alkaloids, saponins, phlobatannins, triterpenes, anthocyanins, cardiac glycosides, leucoanthocyanins and fats, which are bioactive substances. The results could explain scientific validation to the traditional medical uses of B. toxisperma (Pierre) to treat fungal infections.