Comparison of Antioxidative Effects of Polyphenols from Raw Puer Tea in Vitro and Their Protective Effects on Alcoholic Gastric Injury in Mice

In this study,the antioxidant effects of raw Puer tea polyphenols from different years in vitro and their effects on alcoholic gastric lesions in mice were determined. Total polyphenols were extracted from raw Puer tea in 2008,2012 and 2016 years respectively. The contents of total polyphenols were determined by Folin-Phenol method. In addition,the ability of Puer tea polyphenols in three years were determined to remove ABTS⁺ ,DPPH,hydroxyl free radical,and their reducing power in vitro. 50 KM mice were randomly divided into normal group,control group,2008(200 mg/(kg·BW))group,2012(200 mg/(kg·BW))group and 2016(200 mg/kg·BW))group,10 in each group. The 60% volume fraction of ethanol was used to induce acute gastric injury in mice. The gastric juice volume and gastric acid value were measured. The histopathological changes of gastric mucosa were observed by H&E staining. The glutathione(GSH)contents,malondialdehyde(MDA)contents and superoxide dismutase(SOD)activity in serum were determined. The mRNA expression levels of endothelial nitric oxide synthase(eNOS),neuronal nitric oxide synthase(nNOS),and cyclooxygenase-2(COX-2)in mouse gastric tissues were determined by RT-qPCR. Results showed that,Puer tea polyphenols in three years had higher scavenging ability of ABTS⁺,DPPH and hydroxyl free radicals than V_C positive control,and also had strong reducing power. Among them,the antioxidant capacity was:2016 Puer tea polyphenols>2012 Puer tea polyphenols>2008 Puer tea polyphenols. 3 years of Puer tea polyphenols could significantly improve gastric mucosal injury,reduce the secretion of gastric juice,control the gastric acid value in the normal range. 3 years of Puer tea Polyphenols significantly increased SOD activity,increased GSH contents,decreased MDA contents(p<0.05),it also significantly increased mRNA expression of eNOS and nNOS and decreased COX-2 mRNA expression in mouse stomach(p<0.05).Polyphenols from Puer tea have certain inhibitory effects on alcoholic gastric lesions in mice,which would be related to their antioxidative effects,anti-inflammatory and protective factors of gastric mucosa.