Merlot grape pomace hydroalcoholic extract improves the oxidative and inflammatory states of rats with adjuvant-induced arthritis

Grape pomace is an agro-industrial residue produced worldwide. The purpose of this study was to identify and quantify the main phenolics present in an hydroalcohlic extract of a Merlot grape pomace and to investigate its effect on the oxidative and inflammatory states of adjuvant-induced arthritic rats. Daily doses of 250 mg of the extract per kg body weight were administered during 23 days. Several oxidative stress indicators in arthritic rats were maintained at their normal or closely normal levels in the plasma, liver and brain by the treatment. Additionally, the grape pomace also showed significant anti-inflammatory effects. From the 25 phenolics identified in the grape pomace extract the most abundant ones were catechin and catechin derivatives, which are possibly the most important antioxidant agents. The results suggest a potential applicability of the Merlot grape pomace hydroalcoholic extract in the improvement of the oxidative and inflammatory states in arthritic patients.