ORIGINAL PAPER Clovamide-rich extract from Trifolium pallidum reduces oxidative stress-induced damage to blood platelets and plasma Joanna Kolodziejczyk & Beata Olas & Barbara Wachowicz & Barbara Szajwaj & Anna Stochmal & Wieslaw Oleszek Received: 7 January 2011 /Accepted: 16 March 2011 /Published online: 5 April 2011 # University of Navarra 2011 Abstract Numerous plants (including clovers) have been widely used in folk medicine for the treatment of different disorders. This in vitro study was designed to examine the antioxidative effects of the clovamide- rich fraction, obtained from aerial parts of Trifolium pallidum, in the protection of blood platelets and plasma against the nitrative and oxidative damage, caused by peroxynitrite (ONOO - ). Carbonyl groups and 3-nitrotyrosine in blood platelet and plasma proteins were determined by ELISA tests. Thiol groups level was estimated by using 5,5′-dithio-bis (2-nitro-benzoic acid, DTNB). Plasma lipid peroxida- tion was measured spectrophotometrically as the production of thiobarbituric acid reactive substances. The results from our work indicate that clovamide- rich T. pallidum extract may reveal the protective properties in the prevention against oxidative stress. The presence of clovamide-rich T. pallidum extract (12.5–100 μg/ml) partly inhibited ONOO - -mediated protein carbonylation and nitration. All the used concentrations of T. pallidum extract reduced lipid peroxidation in plasma. The antioxidative action of the tested extract in the protection of blood platelet lipids was less effective; the extract at the lowest final concentration (12.5 μg/ml) had no protective effect against lipid peroxidation. The present results indicate that the extract from T. pallidum is likely to be a source of compounds with the antioxidative proper- ties, useful in the prevention against the oxidative stress-related diseases. Keywords Clovamide . Antioxidant . Plasma . Platelets . Peroxynitrite Introduction The increasing trend of herbal supplement utiliza- tion is a result of several factors, mainly the ease of accessibility and the common belief that natural plant-derived products are safer than conventional drugs. The use of plant-derived supplements has been growing in recent years, even though the effects of many phytonutrients on human health and the molecular mechanisms of their action often remain poorly recognized. Therefore, the role of J Physiol Biochem (2011) 67:391–399 DOI 10.1007/s13105-011-0089-z J. Kolodziejczyk (*) : B. Olas : B. Wachowicz Department of General Biochemistry, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland e-mail: joannak@biol.uni.lodz.pl B. Szajwaj : A. Stochmal : W. Oleszek Department of Biochemistry, Institute of Soil Science and Plant Cultivation, State Research Institute, Czartoryskich 8, 24-100 Pulawy, Poland