Antioxidants present in the diet may have a significant effect on the prophylaxis and progression of various diseases associated with oxidative stress. Berries contain a range of chemical compounds with antioxidant properties, including phenolic compounds. The aim of this review article is to provide an overview of the current knowledge of such phenolic antioxidants, and to discuss whether these compounds may always be natural gifts for human health, based on both in vitro and in vivo studies. It describes the antioxidant properties of fresh berries (including aronia berries, grapes, blueberries, sea buckthorn berries, strawberries and other berries) and their various products, especially juices and wines. Some papers report that these phenolic compounds may sometimes behave like prooxidants, and sometimes demonstrate both antioxidant and prooxidant activity, while others note they do not behave the same way in vitro and in vivo. However, no unwanted or toxic effects (i.e., chemical, hematological or urinary effect) have been associated with the consumption of berries or berry juices or other extracts, especially aronia berries and aronia products in vivo, and in vitro, which may suggest that the phenolic antioxidants found in berries are natural gifts for human health. However, the phenolic compound content of berries and berry products is not always well described, and further studies are required to determine the therapeutic doses of different berry products for use in future clinical studies. Moreover, further experiments are needed to understand the beneficial effects reported so far from the mechanistic point of view. Therefore, greater attention should be paid to the development of well-controlled and high-quality clinical studies in this area.

Eugenol is a phenolic aromatic compound obtained mainly from clove oil. Due to its known antibacterial, antiviral, antifungal, anticancer, anti-inflammatory and antioxidant properties, it has long been used in various areas, such as cosmetology, medicine, and pharmacology. However, high concentrations can be toxic. A dose of 2.5 mg/kg body weight is regarded as safe. This paper reviews the current state of knowledge regarding the activities and application of eugenol and its derivatives and recent research of these compounds. This review is based on information concerning eugenol characteristics and recent research from articles in PubMed. Eugenol remains of great interest to researchers, since its multidirectional action allows it to be a potential component of drugs and other products with therapeutic potential against a range of diseases.

The main purpose of this article is to provide an overview of the currently available evidence of antiplatelet properties of resveratrol (3,4('),5-trihydroxystilbene). Resveratrol, a phenolic compound found naturally in fruits, nuts, flowers, seeds and bark of different plants is integral part of human diet. It exhibits a wide range of biological effects, including antiplatelet, anti-inflammatory, anticancer, antimutagenic and antifungal properties. It is also a potent antioxidant, reactive oxygen species scavenger and metal chelators. Resveratrol reduces lipid peroxidation, oxidation and nitration of platelet and plasma proteins. This review article describes the chemical structure of resveratrol, its biological activity, the effects on blood platelet functions and the mechanisms involved in its action on blood platelets, the cells which play an important role not only in the haemostatic process, but also in pathogenesis of cardiovascular diseases.

The generation of superoxide anion radicals (O2*-) and the other reactive oxygen species (ROS) was estimated by means of cytochrome c reduction and chemiluminescence, as well in resting blood platelets and in platelets stimulated by thrombin in the presence or absence of some inhibitors of pathways involved in platelet activation. We used allopurinol (xanthine oxidase inhibitor), wortmannin (PI 3-kinase inhibitor) and staurosporine (protein kinase C inhibitor). To determine the involvement of the glutathione in ROS generation, we used L-buthionine sulfoximine (BSO) which blocks GSH synthesis. Our results confirmed that thrombin stimulates the production of ROS concomitant with metabolism of arachidonate and production of malonyldialdehyde (MDA) in blood platelets (P < 0.05) and showed that, in the presence of inhibitors, the generation of ROS in platelets (resting and stimulated) was reduced. This indicates that xanthine oxidase, PI 3-kinase or protein kinase C take part in the formation of ROS in blood platelets. Moreover, adhesion of platelets to fibrinogen and secretion of adenine nucleotides from platelets after wortmannin and staurosporine action was also inhibited. BSO not only decreased GSH level, but also reduced the amount of ROS; a correlation between the depletion of GSH and the decrease of ROS was observed (R = -0.987; P < 0.02). It is concluded that in blood platelets, ROS are produced in the receptor-mediated signaling pathways and platelet activation (arachidonic acid metabolism, the glutathione cycle, metabolism of phosphoinositoides and due to xanthine oxidase). Our results support the importance of ROS in platelet function.

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