Extract of cactus (Opuntia ficus indica) cladodes scavenges reactive oxygen species in vitro and enhances plasma antioxidant capacity in humans

The purpose of this study was to characterize the in vitro specific reactive oxygen species (ROS) scavenging activity of nopal extracts and to study the effect of nopal consumption on plasma antioxidant capacity. The in vitro hydrolysis of the extract increased its antioxidant activity and the concentration of total polyphenols. The hydrolyzed extract showed ability to scavenge hydroxyl radical, hydrogen peroxide, peroxynitrite anion, superoxide anion and hypochlorous acid. Quercetin, isorhamnetin and kaempferol were identified in this extract by high-performance liquid chromatography (HPLC)/mass spectrometry and vitamin C by HPLC. The antioxidant activity of nopal was compared with that of different foods and the following order was found: coffee > garlic > nopal > plum > chia seeds. Nopal consumption increased blood and plasma antioxidant activity in healthy subjects. Thus, nopal showed in vitro and in vivo antioxidant activity that may be, at least in part, due to the presence of polyphenols and vitamin C.