Comparative effect of fucoxanthin and vitamin C on oxidative and functional parameters of human lymphocytes

The aim of this study was to evaluate the effects of FUCO alone or combined with vitamin C on different features of lymphocyte function related to ROS/RNS (reactive oxygen/nitrogen species) production. For this purpose we have evaluated the cytotoxicity of increasing concentrations of FUCO and vitamin C, the proliferative capacity of stimulated T- and B-lymphocytes, superoxide anion radicals (O-2 center dot), hydrogen peroxide (H2O2) and nitric oxide (NO center dot) production, antioxidant enzyme activities and the indexes of oxidative damage in proteins (carbonyl and thiol content). We have also evaluated the release of inflammatory cytokines and glucose-6-phosphate dehydrogenase (G6PDH) activity. Healthy human lymphocytes were acutely treated in vitro with FUCO (2 mu M) with or without vitamin C (100 mu M). Results revealed that human lymphocytes treated with FUCO at 2 mu M did not present any significant alteration in the proliferation of T- and B-lymphocytes at both resting and stimulated conditions. Moreover, FUCO used at low concentrations showed more pro-oxidant than antioxidant effects, which were recognized by the increased H2O2 and increased NO center dot production. Anti-inflammatory activity of FUCO was confirmed by significantly increased IL-10 and decreased TNF-alpha production. Vitamin C increased T-lymphocyte proliferation, whereas vitamin C plus FUCO promoted a reduction in the proliferation rate of these cells. All groups decreased pro-inflammatory cytokine TNF-alpha and increased anti-inflammatory IL-10 production although only vitamin C decreased IFN-gamma either alone or when combined with FUCO. Overall, the combination of the antioxidants had more antioxidant and anti-inflammatory effects than when they were applied alone. (C) 2014 Elsevier B.V. All rights reserved.