title: Antioxidative effects of extracts from Trifolium species on blood platelets exposed to oxidative stress.
abstract: Clovers (Trifolium) may possess a significant therapeutic potential, but the effects of compounds from these plants on blood platelets and haemostasis have been poorly recognized. The present study was designed to evaluate the antioxidative action of extracts from three species of clovers: Trifolium pratense, Trifolium pallidum and Trifolium scabrum in the protection of human blood platelets in vitro. Platelet suspensions were pre-incubated with crude extract and phenolic fraction of T. pratense or phenolic fractions of T. scabrum and T. pallidum, at the final concentrations of 0.5-50 μg/ml. Then, for the induction of oxidative stress, 100 μM peroxynitrite was added. The antioxidative activity of plant extracts was assessed by measurements of the level of 3-nitrotyrosine, thiol groups and lipid peroxidation products (hydroperoxides and thiobarbituric acid-reactive substances). Despite the significant differences in the composition of the investigated extracts, we observed antioxidative effects of all used mixtures. The presence of Trifolium extracts considerably reduced the peroxynitrite-mediated modifications of proteins and diminished peroxidation of lipids in platelets. Our results indicate on a strong antioxidative activity of the tested extracts-statistically significant effects were found even for the lowest concentrations (0.5 μg/ml) of all extracts. This action may be useful in the protection of blood components, very susceptible to oxidative modifications. The obtained results suggest that the examined clovers are a promising source of compounds, valuable for the protection against oxidative stress-induced damage to blood platelets.
authors.affiliation: Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/3, 90-236, Lodz, Poland, joannak@biol.uni.lodz.pl.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kolodziejczyk-Czepas
authors.forename: Barbara
authors.initials: B
authors.lastname: Wachowicz
authors.forename: Barbara
authors.initials: B
authors.lastname: Moniuszko-Szajwaj
authors.forename: Iwona
authors.initials: I
authors.lastname: Kowalska
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Oleszek
authors.forename: Anna
authors.initials: A
authors.lastname: Stochmal
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D030421:Peroxynitrous Acid / Q000494:pharmacology; D035261:Plant Components, Aerial / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D029921:Trifolium / Q000737:chemistry*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016877:Oxidants; D010936:Plant Extracts; D017392:Thiobarbituric Acid Reactive Substances; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D006861:Hydrogen Peroxide