Antifungal activity of extracts and purified saponins from the rhizomes of Chamaecostus cuspidatus against Candida and Trichophyton species

Aim: To evaluate the antifungal activity of extracts of Chamaecostus cuspidatus against Candida and Trichophyton species.

Methods and results: Crude ethanol extracts of leaves, stems and rhizomes were prepared and evaluated for antimicrobial activity. Only the rhizomes extract (RE) showed antifungal activity but had no inhibitory effect against bacteria (Staphylococcus aureus and Escherichia coli). The RE was then submitted to liquid-liquid partition with hexane (Hex), dichloromethane, chloroform, ethyl acetate and water. The Hex fraction (Hex Fr) from the RE was found to have the best antifungal effect. Three known saponins were isolated from the Hex Fr, of which two (dioscin and aferoside A) showed good antifungal activity. In addition, Hex Fr and the two bioactive compounds had no antibacterial effect, but exhibited fungicidal activity, caused significant changes in the morphology of the fungal cells and showed anti-C. albicans biofilm activity. Finally, the bioactive plant products presented greater selectivity for fungal cells over normal human cells.

Conclusions: The rhizomes of C. cuspidatus have bioactive saponins that function as effective antifungals against Candida and Trichophyton species, and have antibiofilm activity against C. albicans.

Significance and impact of study: Chamaecostus cuspidatus rhizomes extracts may have potential clinical application towards the management of superficial mycoses caused by Candida and Trichophyton species.

Keywords: Chamaecostus cuspidatus; Antifungal activity; Candida spp.; Trichophyton spp; dioscin; saponins.