Determination of antioxidative potential of lichen Usnea ghattensis in vitro

The study was aimed at evaluating the antioxidant activities of extract of Usnea ghattensis. The antioxidant activity, reducing power, superoxide anion radical scavenging and free radical scavenging activities were studied. The antioxidant activity increased with the increasing amount of extracts (2-20mg/ml) added to the linoleic acid emulsion. Lipid peroxidation upto 73.3% was inhibited by the extract of 20 mg/ml and 39.2% by alpha-tocopherol at the same concentration. These effects were statistically significant (r(2) = 0.876, P < 0.01) when compared with control. However, the extract had no significant effect on superoxide anion scavenging by the PMS/NADH-NBT method. Like antioxidant activity, the reducing power and free radical scavenging activity of extract depends on concentration and increasing with increased amount of sample. The reducing power and DPPH radical-scavenging activity of U. ghattensis extract were found greater than the BHA and BHT. The results obtained in the present study indicate that U ghattensis is a potential source of natural antioxidant. (c) 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.