| Cherry has a long history in China.It is very popular because of its bright color and rich nutrition.Cherry contains a variety of bioactive substances,among which polyphenols play an important role in human health.Polyphenols can scavenge free radicals,and have antioxidant and anti-inflammatory activities.Oxidative stress is the decisive factor of many chronic diseases and degenerative diseases.Therefore,the research of polyphenols and other natural active substances provides a new direction for the treatment of diseases.Ulcerative colitis is a kind of inflammatory bowel disease.The pathogenesis of colitis is still unclear.The toxic and side effects of drug treatment of colitis are obvious and the colitis is easy to relapse,increasing the risk of colon cancer.Due to the pro apoptotic and anti angiogenic effects of polyphenols,polyphenols can reduce inflammation,inhibit edema and prevent tumor development.At present,there are few studies on the effect and mechanism of cherry polyphenols on colitis.Therefore,this paper determined the antioxidant activity of cherry polyphenol extracts,identified the composition of cherry polyphenol extracts by HPLC and UPLC-ESI-TOF-MS/MS,and explored the anti colitis effect and mechanism of cherry polyphenol extracts on ulcerative colitis in BALB/c mice induced by DSS.The main results are as follows:(1)Free phenols and bound phenols were extracted from cherry respectively,and their contents were determined by Folin-Ciocalteu method.It was found that free phenols is 6.71 mg GAE/g DW,accounted for 98% of the total phenols,while bound phenols only accounted for 2%.Then ascorbic acid was used as the control to study the antioxidant activity of free phenols and bound phenols.The results showed that Vc and free phenols were significantly higher than bound phenols in DPPH radical scavenging rate and iron reduction ability at the same concentration.For ABTS radical scavenging rate,bound phenol was significantly higher than free phenol and Vc.The ORAC value of free phenol is 297 ?mol TE/g DW,and that of bound phenol is about 8 ?mol TE/g DW.The ORAC of free phenol is much higher than that of bound phenol.The scavenging ability of bound phenol and VC to superoxide anion radical was weak,and the scavenging rate was positively correlated with the concentration,while the free phenol was negatively correlated.For hydroxyl radical scavenging rate,the free phenol content was significantly positively correlated with the scavenging rate,while the bound phenol content had no correlation with the scavenging rate.The above results showed that the antioxidant activities of free phenol and bound phenol were different for different determination methods.(2)HPLC was used for qualitative and quantitative analysis of cherry polyphenol extracts,and five polyphenols,chlorogenic acid,cyanidin 3-O-glucoside,syringic acid,catechin and rutin were identified in free phenols.The content of cyanidin 3-O-glucoside was the highest,which was 1276 ?g/g DW,followed by rutin and chlorogenic acid(177?g/g DW and 153 ?g/g DW),catechin and syringic acid(84 ?g/g DW and 76 ?g/g DW).The results of UPLC-ESI-TOF-MS/MS showed that there were anthocyanins(cyanidin3-O-glucoside,cyanidin 3-O-rutinoside,paeoniflorin 3-O-rutinoside,malvacaine hexoside,pelargonidin 3-rutinoside),hydroxybenzoic acids(protocatechuic acid),hydroxycinnamic acids(caffeoylquinic acid,3-p-coumaroylquinic acid,ferulic acid,dicarboxylic acid),flavonols(quercetin 3-O-rutinoside,quercetin,quercetin 3-Ohexoside,quercetin 7-O-glucoside-3-O-rutinoside)and flavanols(catechins)in free phenols.The bound phenols included anthocyanins(delphinin 3-O-rutinoside,geranium3-rutinoside,delphinin-hexoside),hydroxycinnamic acids(p-coumaric acid),flavonols(quercetin 3-O-rutinoside,kaempferol 3-glucoside)and flavanols(catechins).The results showed that cherry polyphenol extracts mainly contained anthocyanins,hydroxycinnamic acids,flavonols,flavanols and hydroxybenzoic acids.(3)The ulcerative colitis induced by DSS in BALB/c mice was used to investigate the effect of cherry polyphenol extracts on colitis.The results showed that polyphenols could slow down the weight loss trend,reduce DAI index and shorten the length of colon in mice.Polyphenols could also significantly improve the morphology of colonic mucosa and reduce the infiltration of inflammatory cells in mice,and the protective effect of polyphenols was dose-dependent.And polyphenols treatment significantly reduced the thickness of colonic mucosa and muscle layer,alleviated ulcers and edema.What's more,polyphenols decreased the levels of ALT,CAT,GSH-Px and the activity of MDA,increased the activity of SOD in serum,decreased the activity of MPO and the levels of IL-6 and TNF-?,increased the level of IL-10 in colonic mucosa.In conclusion,cherry polyphenol extracts can enhance antioxidant and anti-inflammatory ability,alleviate ulcerative colitis,and reduce inflammatory damage in mice.(4)In order to further explore the anti-colitis mechanism of cherry polyphenol extracts,the tight junction proteins occludin and ZO-1 in colon were analyzed by immunohistochemistry.The results showed that polyphenols could significantly increase the protein contents of occludin and ZO-1 in colonic tissue of mice in a dose-dependent manner.Meanwhile,the expression levels of Wnt pathway proteins ?-catenin,c-myc,Cyclin D1 and GSK-3? were detected by western blot.The results showed that polyphenols could reduce the contents of four proteins in a dose-dependent manner.In conclusion,cherry polyphenol extracts may alleviate ulcerative colitis induced by DSS in mice by protecting tight junction protein,maintaining barrier function and inhibiting abnormal activation of Wnt pathway. |
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