Evaluation of antioxidant potential of the cultured mycobiont of a lichen Usnea ghattensis.

The biologically active compounds, antioxidant activities and free radical scavenging effects of dry matter of cultural medium (DMCM), filtrate (DMF) and different solvent extracts of mycobiont from lichen species Usnea ghattensis in submerged culture (UGSC) were investigated. DMF showed the strongest inhibition of lipid peroxidation as a function of its concentration, and was comparable to the antioxidant activity of BHA at the same concentration of 0.2 mg/mL. The hexane extract of mycobiont had the weakest antioxidant ability, whereas other mycobiont extracts exhibited a modest to strong inhibition of lipid peroxidation and in free radical scavenging activity. The antioxidant activities of mycobiont extracts were correlated with the presence of total polyphenol content in the extract. It was found that antioxidant components in methanol, acetone, ethanol and hexane extracts must be derived from the secondary metabolites produced by the lichen mycobiont. The results presented herein indicate that extracts of cultured mycobiont of lichen Usnea ghattensis could possibly act as chemopreventing agent with respect to free radical-related diseases. Copyright (c) 2005 John Wiley & Sons, Ltd.