Abstract
Blood platelets in addition to their haemostatic role can function as inflammatory cells. The aim of our study was to assess if β-D-glucan, the natural, very strong biological response modifier, may protect platelet proteins and lipids against oxidative/nitrative damages. The antioxidative activity of the β-D-glucan, a known immunomodulator derived from the yeast cell walls of species such as Saccharomyces cerevisiae, on blood platelets treated with oxidants–peroxynitrite and hydroperoxide–was studied in vitro. The levels of different specific markers of oxidative stress, thiobarbituric acid reactive substances (TBARS), carbonyl groups and 3-nitrotyrosine (3-NT) were measured. Our studies showed that β-glucan possesses significant defence properties against peroxynitrite or hydroperoxide induced lipid peroxidation. The level of TBARS was decreased by 80% at the highest dose of β-glucan. In the presence of β-glucan the distinct reduction of platelet protein oxidation was observed; the level of carbonyl groups was decreased by 50%. The results indicate that β-glucan may also be effective in the protection against the nitrative action of peroxynitrite on platelet proteins, as in the presence of β-glucan the level of 3-nitrotyrosine, measured by a competition-ELISA method, was diminished. The obtained in vitro results demonstrate that antiplatelet activity of β-glucan from Saccharomyces cerevisiae is dependent on its antioxidative properties, and therefore β-glucan supplementation may be beneficial in the prevention of excessive blood platelet activation-related diseases, such as cardiovascular or inflammatory diseases.