Assesment of antioxidant status in vivo and in vitro of guarana (Paullinia cupana).

Twelve (12) overweight volunteers will be instructed to gradually reduce the ingestion of coffee, tea, red wine, chocolate and other foods that contain guarana before 15 days before the visit for the blood collection and during the intervention. Consumption of juice fruits may not exceed 300ml per day and alcoholic beverage will be required to be avoided at least 2 days before each visit. Vollunteers will be asked to avoid taking any antioxidant suplement for 2 weeks beforetheir first visit and throughout the ensuing study periods. They will have their blood drawn on a twelve-hour overnight fast (T=1) and one hour after guarana consumption the second blood sample will be collected (T=2). Fifteen days after drinking the beverage made with guarana powder (3g) diluited in cold 300 ml water, two blood samples will be collected: one on a twelve-hour overnight fast (T=3) and other after the fisrt hour of drinking the beverage (T=4). Lipid profile of the volunteers will be evaluated on the begging and in the end of the intervention. Plasma and LDL at the four moments will be submitted to oxidation by copper (Cu+2) and after that the kinetics of diene conjugate generation and thiobarbituric acid reactive substance (TBARS) will be evaluated as well antioxidant activity of the enzymes gluthatione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in erythrocites. Antioxidant Total Status of the plasma will be determinated. The Deoxyribonucleic acid (DNA) damage will be analyzed in blood lymphocytes using the Comet Assay. The Comet assay successfully assess interactions of antioxidants with genotoxicants and it has also proved a valid technique to evaluate whether antioxidant/micronutrients are able to protect the integrity of the genetic material.