Abstract: In this paper, a novel tripeptide was isolated at a concentration of (18.78 ± 0.34) μg/L from Chinese Baijiu by direct condensation, and its structure was identified as Arg-Asn-His (RNH) by high performance liquid chromatographquadrupole- time-of-flight mass spectrometry. The synthetic RNH was used to explore the protective effect of RNH on oxidative damage induced by 2,2’-azobis(2-methyl propionamidine) dihydrochloride (AAPH) in human hepatoma cells (HepG2). The results showed that RNH had a potent scavenging effect against intracellular reactive oxygen species by increasing the activities of antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and the level of reduced glutathione in the cells. In addition, it prevented the increase of malondialdehyde level and decreased AAPH-induced lipid peroxidation level, thereby enhancing cellular antioxidant defense capacity. The antioxidant activity of the peptide was dose dependent. The results of this study can provide better understanding of the relationship between Chinese Baijiu and health.

Key words: Chinese Baijiu, peptide, high performance liquid chromatograph-quadrupole-time-of-flight mass spectrometry, antioxidant activity, HepG2 cell