Antioxidant and Anti-adhesive Activity of Some Common Lichens

摘要

Antioxidant, antimicrobial and anti-adhesive activity of six lichens in Central Texas region (Ramalina celastri (RA), R. stenospora (RS), R. Americana (RA), T. chrysopthalmus (TC), Parmotrema austrosinese (PA) and P. perforatum (PP)) was evaluated. Antioxidant activity was determined by Malondialdehyde (MDA) assay and ABTS radical quenching assay. Antimicrobial and anti-adhesive activity of sterile extracts against P. aeruginosa was determined by Kirby-Bauer disk diffusion assay and ex-vivo skin assay, respectively. The high molecular weight fraction (HMWF) had higher antioxidant activity and quenched 60-75% radicals compared to the low molecular weight fraction (LMWF) which only neutralized 20-40% of the radicals except PA where activity was 79%. All extracts were able to reduce MDA formation by 30-88% except LMWF of RA and PP. None of the extracts had antimicrobial activity in the Kirby-Bauer (KB) disc diffusion assay. All the HMWF were able to reduce adhesion of P. aeruginosaby 30-55% except PP. LMWF from RS, PP, PA and PP reduced bacterial adhesion by 41-54%. Present results suggest that lichens can be an important source for bioactive compounds with potential benefits against oxidative and infectious diseases and warrants further investigation.