The antioxidant activity and active component of Gnaphalium affine extract.

The antioxidant activity of Gnaphalium affine extract (GAE) against H2O2-induced oxidative injury in Caco-2 cells was evaluated, and the main antioxidant component was isolated and identified by column chromatography, high performance liquid chromatography, time-of-flight mass spectrometer and nuclear magnetic resonance. In vitro assays, GAE showed remarkable antioxidant activity to scavenge free radicals (ABTS, DPPH, superoxide and hydroxyl radicals), inhibit lipid peroxidation and show reducing power. In food system, GAE exhibited the obvious capacity to inhibit the oxidation of peanut oil and lard, which may be attributed to its high content of phenolic compounds. Moreover, GAE could effectively protect Caco-2 cell against H2O2-induced oxidative injury. With the isolation and purification by chromatography, quercetin was identified as the main antioxidant component of GAE, which was capable of scavenging ABTS, DPPH, superoxide and hydroxyl radicals. These results suggest that G. affine is a potential source for preparing functional foods and nutraceuticals in food industry.