Ayurvedic herbal extracts suppress Candidal biofilms in vitro

Abstract

Plant derivatives have been used for centuries to treat various health disorders of the human including microbial infections. A vast majority of these infections are initiated and perpetuated by biofilms. This study 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 was first investigated against the planktonic C. albicans and C. tropicalis using well diffusion method. 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, 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 of C. tropicalis. Further, biofilm inhibition was seen in the co-cultured mixed species C. albicans and C. tropicalis biofilms with Triphala treatment. Triphala did not have any inhibitory effect on C. albicans. M. elengi had no inhibitory effect on biofilms of either Candida species. Scanning electron microscopy (SEM) revealed increased cell density of C. albicans in the biofilm. However, Triphala treatment had an inhibitory effect against C. tropicalis biofilms. SEM imaging revealed altered cell morphology of C. tropicalis cells in the biofilm after exposure to Triphala. In conclusion Triphala, but not M. elengi, extracts exhibit selective and differential biofilm inhibitory activity against Candida species. C. albicans biofilms are more resistant to the anti-biofilm activity of Triphala.