Antifungal activity and toxicity of bioactive compounds isolated from the leaf of Ximenia caffra Sond. var. natalensis

Abstract

BACKGROUND : Based on high frequency index, Ximenia caffra Sond. var. natalensis was selected for further phytochemical investigation and biological assays. Aim: The study aimed to isolate the active antifungal compounds from the leaves of X. caffra var. natalensis. SETTING : The ethnobotanical study was conducted in Aganang Local Municipality, Capricorn District. METHODS : Acetone extract was partitioned five times with hexane, chloroform, ethyl acetate, butanol and water, respectively. Fractions were screened for antifungal activity against Candida albicans using the microplate method and bioautography assays. The structures of isolated compounds were identified using nuclear magnetic resonance (NMR) and mass spectrometry. Cytotoxicity of isolated compounds was determined using 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide (MTT) assay. RESULTS : Bioassay-guided fractionation of the ethyl acetate fraction led to the isolation of four compounds, out of which only two were identified. Compound 1 was identified as epigallocatechin gallate, and Compound 3 was confirmed as kaempferol-3-O-rhamnoside. Epigallocatechin gallate exhibited moderate antifungal activity with minimum inhibitory concentration (MIC) of 0.5mg/mL and less toxic to the cells with LC50 = 32.32 μg/mL. CONCLUSION : The antifungal activity and cytotoxicity of isolated compounds validate the use of X. caffra Sond. var. natalensis in combating oral candidiasis. CONTRIBUTION : The results have shown the potential bioactivity of X. caffra Sond. var. natalensis in the treatment of oral candidiasis.