Isolation and semi-purification of active components from Philippine plants against Candida albicans

There is a need for antifungal discovery driven by (1) the increase in incidence and prevalence of fungal infections, and (2) the limitations of existing antifungal drugs. This study isolated and semi-purified the antifungal constituents against Candida albicans of four Philippine plants: (1) Basella rubra stems and leaves, (2) Colocasia esculenta stems and leaves, (3) Curcuma longa rhizome, and (4) Caryota rumphiana bark and stems. The minimum inhibitory concentration (MIC) of all extracts were greater than 32 μg/mL (MICketoconazole: 16 μg/mL), but the three most active extracts (minimum biofilm inhibitory concentration, MBICC. longa rhizome: 20 μg/mL, MBICC. esculenta stem: 40 μg/mL, and MBICC. rumphiana bark:40 μg/mL) had comparable biofilm inhibitory activities to that of the comparator drug (MBICketoconazole: 40 μg/mL). For semi-purification, the most active solvent fractions were C. longa rhizome aqueous fraction, C. rumphiana bark aqueous fraction, and C. esculenta stem ethyl acetate fraction. All three had MICs equal to 32 μg/mL. C. longa rhizome aqueous fraction and C. rumphiana bark aqueous fraction had MBICs equal to 40 μg/mL. These suggest that C. longa rhizome and C. esculenta stem may be more suited for formulation as crude botanical preparations. On the other hand, it is recommended that C. rumphiana bark be subjected to further isolation. For characterization, C. rumphiana aqueous fraction tested positive for triterpenes. In thin layer chromatography, a spot with Rf:0.05 was found to have a higher concentration in C. rumphiana aqueous fraction than in the crude extract.