Biochemical mechanism underlying the effects of polyphenols: implications for vascular disease

C. G. FRAGA

Sao Pedro

Congreso; 2011 Congress South American of Free Radical Group; 2011

South American of Free Radical Group

Polyphenols include several groups of naturally occurring plant compounds, which biological effects could explain some of the health benefits linked to the consumption of fruit and vegetables. Polyphenols molecular actions depend on the active chemical species (parent compound or metabolite), and on the amount available to interact with the target entity. Presence of polyphenols ranges from sub-nanomolar to high micromolar concentrations, and are mainly dependent on the tissue and the conditions of polyphenol provision. Subjected to these considerations, the study of the effects of flavanols on hypertension has advanced steadily in the last years, providing evidence on the mechanisms relating flavanol consumption/presence and the regulation of vascular function, and hence blood pressure. Among the events explaining the observed effects of flavanols in the vasculature the following are relevant: i) NADPH oxidase regulation and superoxide production; ii) eNOS regulation and NO production; iii) regulation of NF-êB and other signaling molecules involved in inflammation. Many of these actions seem to be interrelated, e.g. superoxide and NO regulation; and mediated by membrane related events, i.e. TNFá-mediated effects. It can be concluded that: i) polyphenol effects on biological systems cannot be reduced to generic effects, e.g. antioxidant capacity; ii) given the very low concentrations of polyphenols in biological system, specific interactions with protein, lipids, etc., seem more operative that unspecific actions that need higher concentrations; iii) there are concrete mechanisms that substantiate the participation of certain flavanols and/or polyphenols in the health benefits of fruits and vegetables. Supported by UBACyT (01-1111). CGF is member of CIC, CONICET, Argentina.