Effects of two lichen acids isolated from Pseudevernia furfuracea (L.) Zopf in cultured human lymphocytes

The present study aims at assessing the efficacies of olivetoric acid (OA) and physodic acid (PA) isolated from Pseudevernia furfuracea (L.) Zopf (Parmeliaceae) in human lymphocytes (HLs) in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays were performed to establish cytotoxicity in HLs. Besides, oxidative stress and genotoxicity were monitored by estimating the changes of total oxidative stress (TOS) and 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels, respectively, in HLs. At the same time, OA- and PA-induced total antioxidant capacity (TAC) levels in HLs were determined. Although especially low concentrations of OA (IC50 = 109.94 mg/L) and PA (IC50 = 665.49 mg/L) did not show cytotoxic effect at high levels in HLs, it was revealed that cytotoxicity was significantly (p < 0.05) associated with oxidative stress and genotoxicity via correlation analysis. While TOS level in HLs did not statistically (p > 0.05) increase in the presence of all treatments (0.5-100 mg/L) of PA, TAC level was increased by PA applications in certain concentrations (0.5-10 mg/L). Overall, the obtained data indicate that OA and especially PA as lichen compounds that do not cause oxidative stress can be a new resource of therapeutics as recognized in the present study with their high antioxidant features.