Ayurvedic, herbal extracts suppress Candidal biofilms in vitro

Abstract

Plant derivatives have been used for centuries to treat various human afflictions including microbial infections. A vast majority of these infections are initiated and perpetuated by community dwelling, surface-attached organisms living in micro-econiches known as biofilms. We investigated the biofilm suppressant effect of phytomedicinal preparations used widely in traditional Ayurvedic medicine, Triphala, a mixture of Terminalia bellirica, Terminalia chebula and Emblica officinalis, and Mimusops elengi bark extract. Inhibitory effect of extracts were first investigated against the planktonic C. albicans and C. tropicalis using the well diffusion. Minimum biofilm inhibitory concentration for in-vitro biofilms was determined by MTT assay. The biofilm suppressant effect was determined by measuring biofilm viability at different time intervals, post-exposure to the two herbal extracts, and using MTT. Scanning electron microscopy was performed to assess the post-exposure biofilm architecture. Triphala inhibited both species of the planktonic yeasts, and only the biofilm phase C. tropicalis and mixed species, and not C. albicans. M. elengi had no inhibitory effect on either the planktonic or the biofilms of either Candida species. Ultrastructural microscopy revealed increased cell density of C. albicans biofilm, but not that of C. tropicalis which was significantly reduced in size after Triphala exposure. Triphala, but not M. elengi, extracts exhibit selective and differential biofilm inhibitory activity against Candida. C. albicans biofilms are more resistant to the anti-biofilm activity of Triphala.