The Antioxidant and Anti-Fatigue Effects of Rare Ginsenosides and γ-Aminobutyric Acid in Fermented Ginseng and Germinated Brown Rice Puree

γ-aminobutyric acid (GABA) and rare ginsenosides are good antioxidant and anti-fatigue active components that can be enriched via probiotic fermentation. In this study, ginseng and germinated brown rice were used as raw materials to produce six fermented purees using fermentation and non-fermentation technology. We tested the chemical composition of the purees and found that the content of GABA and rare ginsenoside (Rh4, Rg3, and CK) in the puree made of ginseng and germinated brown rice (FGB) increased significantly after fermentation. The antioxidant activity of the six purees was determined using cell-free experiments, and it was found that FGB had better ferric-ion-reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging rates, exhibiting better antioxidant effects. We then evaluated the antioxidant effect of FGB in HepG2 cells induced by H2O2 and found that FGB can reduce the generation of reactive oxygen species (ROS) in HepG2 cells and increase the membrane potential level, thereby improving oxidative damage in these cells. In vivo experiments also showed that FGB has good antioxidant and anti-fatigue activities, which can prolong the exhaustive swimming time of mice and reduce the accumulation of metabolites, and is accompanied by a corresponding increase in liver glycogen and muscle glycogen levels as well as superoxide dismutase and lactate dehydrogenase activities. Finally, we believe that the substances with good antioxidant and anti-fatigue activity found in FGB are derived from co-fermented enriched GABA and rare ginsenosides.