Metabolic Profiling Analysis Of Different Grades Of Lu’an Guapian And Their Prevention Effect On Metabolic Syndrome In High-fat Diet Induced C57BL/6 Mice

Metabolic syndrome(MetS)is a significant public health problem,which including insulin resistance,oxidative stress and chronic inflammation.Dietary,pharmacological,and surgical strategies have been developed in the last decade to prevent the metabolic effects of a high-fat diet.there are still several risks associated with pharmacological and surgical intervention of obesity and the MetS,suggesting that dietary modification may be the safest and most cost-effective option for those who are moderately obese.To date,nutritional intervention is still the preferred method of treatment and prevention for obesity and the metabolic syndrome.Lu’an guapian green tea(LGGT)is one of the most famous green tea in China.The unique character of this tea is that made with only leaves,without buds and young stem of Camelia sinensis.Comparative investigation of health effects of different grades of this tea have not been evaluated yet.The aim of the study was to establish a health-based evaluation system to justify different grades of LGGT,and to provide healthy information to tea consumers.Based on this,non-targeted ultra-performance liquid chromatography Orbitrap mass spectrometry(UPLC-Orbitrap-MS)was used to analyze chemical profiles of six different grades of LGGT.In total,64 metabolites were structurally identified,including 8 catechins,2 dimeric catechins,12 flavonol and flavonol/ flavone glycosides,13 phenolic acids,13 amino acids,2 organic acids and 14 alkaloids,wherein 9 low abundant metabolites showed distinct changes in abundance that were closely correlated with tea grade variation.GC,C,epicatechin 3-O-(3-O-methygallate,theasinensin C,theasinensin B,salicylic acid,gallic acid,kaempferol 3-(6’’-rhanmnosylsoporoside and l-linalool 3-[xylosyl-(1->6)-glucoside]which findings suggested their potential as markers to discriminate different grades of LGGT.Hierarchical clustering analysis of chemical profiles showed that premium grades clustered together first,and then do first and second grades,and the third grade and summer LGGT grouped last.High-fat-diet(HFD)induced metabolic syndrome of C57BL/6J mice were used to evaluate health benefits of the six grade LGGT.The C57BL/6J mice were assigned for following groups to feed different diets for 10/20 weeks: chow diet(C),high-fat-diet(HFD)or HFD supplement with the premium LGGT(HFD+PG),HFD with first LGGT(HFD+FG),HFD with third LGGT(HFD+TG)and HFD with the summer LGGT(HFD+Sum G).Our data showed that dietary supplement of different grades of LGGT reduced the body weight,body fat mass and preventive fatty liver formation,improved blood lipid panel induced by high-fat diet;and effectively decreased the blood glucose elevation and improved glucose tolerance and insulin sensitivity in high-fat-diet induced C57BL/6J mice that were intervening.After 20 weeks of intervention,more stable and obvious symptoms appeared.Furthermore,the dietary supplement of LGGT about 20 weeks obviously reduced the expression of lipid synthesis related genes fatty acid synthase,the sterol regulatory element-binding transcription factor 1 and acetyl-Co A carboxylaseα,while the lipid catabolic genes were not altered in the liver of HFD induced C57BL/6J mice.And also the dietary supplement of LGGT improved the expression of insulin receptor substrate 1,forkhead box protein o1,phosphoenolpyruvate carboxykinase.Over all,the premium grade LGGT has the best effect on prevention of obesity and metabolic abnormalities in HFD induced C57BL/6J mice compared to the summer grade LGGT group mice.The above results show that six different grades of LGGT could be divided into three different grades,including super grade(super grade and super grade),first grade(first,second and third grade)and summer LGGT(summer LGGT)which based on chemical composition analysis and health function study.