Pycnogenol (R) (PYC), a standardized plant extract obtained from the bark of the French maritime pine Pious pinaster, has been suggested to exert strong antioxidant activity and used as a phytochemical remedy for various diseases. In this study, we investigated the antioxidant capacity of PYC by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxicity by neutral red uptake (NRU) test in Chinese Hamster Ovary (CHO) cells. The genotoxic and antigenotoxic effects of PYC were evaluated by the cytokinesis-blocked micronucleus (CBMN) and alkaline comet assays in human peripheral blood lymphocytes. At the concentrations of 2-200 mu g/ml, PVC was found to have antioxidant activity. The viability of CHO cells during 24 h exposure were not affected at the concentrations of 5-150 mu g/ml of PVC. IC50 value of PVC was found to be 285 mu g/ml. At the concentrations above 100 mu g/ml, PYC alone induced DNA damage and increased MN frequency, although PVC at all concentrations in a dose dependent manner revealed a reduction in the frequency of MN and the extent of DNA damage induced by H2O2. These results suggest PYC might reduce H2O2 induced chromosome breakage and loss and DNA damage in cultured human lymphocytes. (C) 2013 Elsevier Ltd. All rights reserved.