Biological capacity and chemical composition of secondary metabolites from representatives Japanese lichens

Abstract

Lichens represent a well-known symbiotic system. Brachythecium velutinum (Brown), Brachythecium rutabulum, Lepraria incana, Brachythecium velutinum (Green) and Dirinaria applanata were collected from the tree trunks and rocks in Japanese forests. The alcoholic extracts of these lichens were examined for their antioxidant and cytotoxicity effect. Dirinaria applanata methanolic extract (2.5 mg /mL-1) was the most active in scavenging DPPH free radical (75.09±0.37%) and in reducing Fe3+/ferricyanide complex to the ferrous form (1.88±0.03). It was also the most potent in ABTS·+ scavenging activity using ABTS assay 89.35%)at a concentration (0.5 mg.mL-1). Brachythecium rutabulum and Dirinaria applanata extracts demonstrated a significant in vitro cytotoxic effect on 549 human lung carcinoma cell line with IC50 values (34.7±2.1 and 38.6±2.8) μg/mL, respectively. Dereplication of these extracts using LC-HRMS was performed to gain insight about secondary metabolism profiles of these lichens and their rule in the antioxidant and cytotoxic activities.