The aim of the study was to investigate phenolic composition, antioxidative, protective and cytotoxic effects of Pleurotus eryngii and Auricularia auricula-judae. Analysis of phenolic compounds in these edible mushrooms species has been carried out by high-performance liquid chromatography (HPLC). Protective effect of these mushrooms on H2O2 induced oxidative cell damage was determined by using MTT (3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole) assay. Antioxidant activities of the mushrooms extracts were evaluated by using complementary in vitro assays. In addition, the measurement of total antioxidant compounds in the extracts was carried out. All the extracts exhibited protective effect against H2O2 induced oxidative cell damage but the highest activity was observed for A. auricula-judae aqueous extract (89.5 +/- 1.8% cell viability at 0.1 mg/ml). P. eryngii methanolic extract showed the highest ferrous iron chelating ability (IC50 = 0.42 +/- 0.03 mg/ml). A. auricula-judae extracts (at concentration of 0.025-0.100 mg/ml) were not toxic to baby hamster kidney fibroblast cell line (BHK 21). These results suggest that these mushrooms may be used as a potential source of natural antioxidants for food supplementation or in the development of nutraceuticals. (C) 2011 Published by Elsevier Ltd.