Hippophae rhamnoides L. Fruits Reduce the Oxidative Stress in Human Blood Platelets and Plasma

Effects of the phenolic fraction from Hippophae rhamnoides fruits on the production of thiobarbituric acid reactive substances (TBARS, a marker of lipid peroxidation) and the generation of superoxide anion (O(2) (−∙)) in human blood platelets (resting platelets and platelets stimulated by a strong physiological agonist, thrombin) were studied in vitro. We also examined antioxidant properties of this fraction against human plasma lipid peroxidation and protein carbonylation induced by a strong biological oxidant, hydrogen peroxide (H(2)O(2)) or H(2)O(2)/Fe (a donor of hydroxyl radicals). The tested fraction of H. rhamnoides (0.5– 50 µg/mL; the incubation time: 15 and 60 min) inhibited lipid peroxidation induced by H(2)O(2) or H(2)O(2)/Fe. The H. rhamnoides phenolic fraction inhibited not only plasma lipid peroxidation, but also plasma protein carbonylation stimulated by H(2)O(2) or H(2)O(2)/Fe. Moreover, the level of O(2) (−∙) in platelets significantly decreased. In comparative experiments, the H. rhamnoides fraction was a more effective antioxidant than aronia extract or grape seed extract (at the highest tested concentration, 50 µg/mL). The obtained results suggest that H. rhamnoides fruits may be a new, promising source of natural compounds with antioxidant and antiplatelet activity beneficial not only for healthy people, but also for those with oxidative stress-associated diseases.