title: Usnic acid inhibits biofilm formation and virulent morphological traits of Candida albicans.
abstract: Biofilm formation and the yeast to hyphal switch are considered to be important virulence factors of Candida albicans. The present study reports about the potential of usnic acid, a lichen secondary metabolite inhibiting these virulent factors. Usnic acid, at its biofilm inhibitory concentration (BIC) largely reduced the viability of the metabolically active cells in matured C. albicans biofilms, exhibited significant biofilm inhibition (65%) and prevented the property of adhesion. Light microscopic images revealed that usnic acid effectively inhibited the yeast to hyphal switch and confocal microscopy showed that usnic acid greatly reduced the thickness of matured biofilms. Furthermore, usnic acid was able to reduce various sugars present in the exopolysaccharide layer (EPS) which was also confirmed by FT-IR analysis. Taken together, the present study showcases usnic acid as a potent anti-virulent compound against C. albicans and opens up a new avenue for bioprospecting lichen secondary metabolites as anti-virulent compounds.
authors.affiliation: Biofilm Biology Laboratory, Anusandhan Kendra II, School of Chemical & Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur, Tamil Nadu, India; Centre for Research on Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA University, Tirumalaisamudram, Thanjavur, Tamil Nadu, India. Electronic address: pnithyanand@gmail.com.
authors.forename: Paramasivam
authors.initials: P
authors.lastname: Nithyanand
authors.affiliation: Department of Biotechnology, Alagappa University, Science Campus, Karaikudi 630004, Tamil Nadu, India.
authors.forename: Raja Mohmed
authors.initials: RM
authors.lastname: Beema Shafreen
authors.affiliation: Department of Biotechnology, Alagappa University, Science Campus, Karaikudi 630004, Tamil Nadu, India.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Muthamil
authors.affiliation: Department of Biotechnology, Alagappa University, Science Campus, Karaikudi 630004, Tamil Nadu, India.
authors.forename: Shunmugiah
authors.initials: S
authors.lastname: Karutha Pandian
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001572:Benzofurans / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D025301:Hyphae / Q000187:drug effects; D008011:Lichens / Q000378:metabolism; D018613:Microscopy, Confocal; D017550:Spectroscopy, Fourier Transform Infrared; D014774:Virulence / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D001572:Benzofurans; C073339:usnic acid
keywords: Biofilms; Candida morphogenesis; Lichen secondary metabolite