Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/3, 90-236, Lodz, Poland,
J Physiol Biochem. 2013 Dec;69(4):879-87. doi: 10.1007/s13105-013-0264-5. Epub 2013 Jun 8.
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.
三叶草（Trifolium）可能具有重要的治疗潜力，但这些植物的化合物对血小板和止血的影响尚未得到充分认识。本研究旨在评估三种三叶草（紫花苜蓿、白三叶草和糙叶三叶草）提取物的抗氧化作用，以保护体外人类血小板。将血小板悬浮液与粗提取物和紫花苜蓿的酚类部分或糙叶三叶草和白三叶草的酚类部分在 0.5-50μg/ml 的最终浓度下预孵育。然后，加入 100μM 过氧亚硝酸盐诱导氧化应激。通过测量 3-硝基酪氨酸、巯基基团和脂质过氧化产物（氢过氧化物和硫代巴比妥酸反应物质）的水平来评估植物提取物的抗氧化活性。尽管研究提取物的组成存在显著差异，但我们观察到所有使用混合物的抗氧化作用。三叶草提取物的存在大大减少了过氧亚硝酸盐介导的蛋白质修饰，并减少了血小板中的脂质过氧化。我们的结果表明，测试提取物具有很强的抗氧化活性-即使对于所有提取物的最低浓度（0.5μg/ml），也发现了统计学上显著的效果。这种作用可能有助于保护血液成分免受易受氧化修饰的影响。所得结果表明，所检查的三叶草是一种有前途的化合物来源，可用于防止氧化应激诱导的血小板损伤。
