不同年份生普洱茶多酚体外抗氧化效果及对小鼠酒精性胃损伤的保护作用比较

本文对不同年份生普洱茶多酚的体外抗氧化效果及其对小鼠酒精性胃损伤的保护作用进行了研究。分别从2008年、2012年和2016年生普洱茶中提取总多酚物质,采用福林-酚法测定总多酚含量,分别测定3个年份生普洱茶多酚体外清除2,2′-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)自由基、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)、羟基自由基的能力以及测定其还原力。将50只清洁级昆明小鼠随机分为正常组、模型组、2008年组(200 mg/(kg·BW))、2012年组(200 mg/(kg·BW))和2016年组(200 mg/(kg·BW)),每组10只。采用60%乙醇溶液诱导小鼠急性胃损伤模型,测定小鼠胃液量和胃酸值,H&E染色观察小鼠胃黏膜的组织形态改变,测定小鼠血清谷胱甘肽(glutathione,GSH)含量、丙二醛(malondialdehyde,MDA)含量及超氧化物歧化酶(superoxide dismutase,SOD)活力,采用RT-qPCR测定小鼠胃组织中内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)、神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)和环氧合酶2(cyclooxygenase-2,COX-2)的mRNA表达水平。结果表明,3个年份生普洱茶多酚对ABTS^+自由基、DPPH自由基和羟基自由基清除能力均高于V_C阳性对照,同时还具有较强的还原力,综合比较抗氧化能力大小为:2016年生普洱茶多酚>2012年生普洱茶多酚>2008年生普洱茶多酚;3个年份的生普洱茶多酚均能明显改善胃黏膜损伤,减少胃液量分泌,维持正常胃酸值;3个年份生普洱茶多酚均可显著增加小鼠血清中SOD酶活力,增加GSH含量,降低MDA含量(p<0.05),还能显著增加小鼠胃组织中eNOS、nNOS的mRNA表达,降低COX-2的mRNA表达(p<0.05)。综上,生普洱茶多酚对小鼠酒精性胃损伤具有一定的抑制作用,这可能与其抗氧化效果、抗炎及增强胃黏膜保护因子等作用有关。

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.