Lipid peroxidation and tyrosinase inhibition by lichen symbionts grown in vitro

Abstract

The symbionts of lichen species Arthothelium awasthii, Heterodermia podocarpa, and Parmotrema tinctorum were 
isolated and cultured on various nutrient media incubated in a growth chamber. Methanolic extracts of one year old 
symbiont cultures were taken for evaluating their potential to inhibit lipid peroxidation and tyrosinase enzyme activity. 
The extracts of all cultured lichen-symbionts have shown a concentration-time dependent inhibition of lipid 
peroxidation and tyrosinase activities. IC50 values for inhibition of lipid peroxidation by culture-extracts were 15.7 µg 
for A. awasthii, 12.68 µg for H. podocarpa and 11.47 µg for P. tinctorum. Testing the impact of the extracts on 
tyrosinase activity, we found IC50 of 8.71 µg (A. awasthii), 14.55 µg (H. podocarpa) and 12.44 µg (P. tinctorum). 
According to their IC50 the tested extracts turned out to be more effective for the tested parameters than the standard 
antioxidant Trolox (IC50 for lipid peroxidation 16.13 µg) and Kojic acid tyrosinase inhibitor (IC50 for tyrosinase 
inhibition 17.63 µg). The results suggest possible applications of lichen substances in the extracts of A. awasthii, H. 
podocarpa, and P. tinctorum symbionts as natural tyrosinase inhibitors.