In vitro effect of guaraná on total radical-trapping antioxidant potential (TRAP). The reaction mixture contained 10 mM AAPH, 35 μM luminol and guaraná at different concentrations dissolved in 0.1 M glycine buffer (pH 8.6). The luminescence was measured every 5 minutes during 5 hours. The area under curve (AUC) was evaluated. (V) Vehicle and (C) Control. The bars represent mean ± S.D. of five different experiments. * p < 0.001 compared to control and vehicle group. There is no difference between vehicle and control group.