The cytotoxic potential of polyphenols extracted from eight lichen species and their antioxidant activity against the cancer cell lines

This article presents the results of in vitro experiments on the cytotoxic potential of ethanol extracts from 8 lichen species, Cetraria islandica, Cladonia arbuscula, C. digitata, C. gracilis, C. rangiferina, C. uncialis, Platismatia glauca and Pseudevernia furfuracea, against 5 human cancer cell lines - MCF-7, Caco-2, SK-mel-28, U87MG and Jurkat.

The potential of the re-dissolved and then tested extracts was determined by means of TPC, free radical scavenging activity in ABTS^•+, superoxide and hydroxyl tests, copper ion reduction activity, and chelating ability of ferrous ion. The highest TPC (114.29 mg GAE/g), ABTS^•+ (440.61 mmol TE/100 g) and hydroxyl (IC₅₀: 0.71 mg/mL) radical scavenging activities tests was obtained for the Pseudevernia furfuracea extract, and for the superoxide radical scavenging activity test (IC₅₀: 0.98 mg/mL), the highest potential was found for the extracts from P. furfuracea and Cladonia digitata, and for the copper ion reduction activity (88.15 mmol TE/100 g) and chelating ability of ferrous ion (IC₅₀: 1.83 mg/mL) tests, the highest potential was shown for the extract from C. digitata. In the cytotoxicity tests, the strongest potential was shown by the P. furfuracea extract against the MCF-7 (IC₅₀: 110.84 μg/mL), Caco-2 (IC₅₀: 123.86 μg/mL) and U87MG (IC₅₀: 107.43 μg/mL) cancer cell lines. A wound scratch test against the MCF-7 using Pseudevernia furfuracea extract showed a 50% reduction in tumor cell proliferation. The qualitative - 28 secondary metabolites from depside and depsidones classes - and quantitative profile of lichen extracts was analyzed by UPLC-Q-TOF-MS/MS.