Characteristics, Chemical Analysis and Biological Activities of Methanol Extracts of Lichens Pleurosticta acetabulum and Cladonia subulata

Abstract The aim of this study is to investigate the chemical composition of methanol extracts of the lichens Pleurosticta acetabulum and Cladonia subulata and their antioxidant, and anticancer activities. The phytochemical analysis of the extracts of lichens was determined by HPLC-UV method. The predominant phenolic compounds in these extracts were norstictic acid and salazinic acids in P. acetabulum, while hypoprotocetraric acid and fumarprotocetraric acid were the major metabolites detected in C. subulata. Total phenolics and flavonoids in the extracts were determined spectrophotometrically, with the varied amount from 21.31 to 73.45 mg GA/g and from 8.48 to 15.42 mg RU/g, respectively. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, inhibitory activity towards lipid peroxidation and reducing power. Cytotoxic effects of lichens were tested against HeLa S3 and LS174 cell lines using MTT method.The cytotoxic effects of P. acetabulum and C. subulata extracts toward two cancer cell lines were in the range from 39.17 to >200 μg/mL IC50 value. The present study showed that the tested extracts of lichens demonstrated important antioxidant and anticancer effects. That suggests that these lichens can be used as new sources of the natural antioxidants and anti-cancer compounds.