Instant Dark Tea Alleviates Hyperlipidaemia in High-Fat Diet-Fed Rat:From Molecular Evidence to Redox Balance and Beyond

Si Qin",Zhilan He', Yuanjie Wu2, Chaoxi Zeng'. Zhibing Zheng', Haowei Zhang'. Chenghao Lv', Yong Yuan', Haoren Wu2,Jianhui Ye',Zhonghua Liu" and Meng Shi'"

'Lab of Food Function and Nutrigenomics,Colege of Food Scence and Tectmolbgy,Hunan Agncultural University. Changsha,ChinaHunan Tea Group Ca. LTD.Changsha,China,'Tea Rescarch nstitute,Zhojiang Unwersity,Hangzhou China.*Key Laboratory of Ministry of Education for Tea Soence,Hunan Agncultural Unversity,Changsha.Chna

Instant dark tea (IDT) is a new product gaining increasing attention because it is convenient and can endow significant health benefit to consumers, which is partially attributed to its high concentration of functional ingredients.However,the molecular mechanism underlying its regulatory effect on hyperlipidaemia is rarely studied. In this study.we performed omics and molecular verification in high-fat diet(HFD)-fed rat,aiming to reveal the mechanism and provide molecular evidence.The results showed that the major bioactive components in IDT were indude 237.9 mg/g total polysaccharides,336.6 mg/g total polyphenols,and 46.9 mg/g EGCG.Rats fed with IDT (0.27-0.54 g/kg for 12 weeks) significantly reduced the body weight and TC,TG,LDL-C,blood glucose,and MDA and induced the level of serum HDL-C and also the levels of liver SOD,CAT,GSH-Px,and Nrf2,compared to HFD group.For molecular mechanism study,HIDT feeding had significant impact on the gene expressions of biomarkers in lipogenesis(FABP. CD36,SCD1,Cyp4a1, and Kcnn2). ipid oxidation (PPARy), and glucose glycolysis (Gck and ENO2)in liver tissue.Moreover,gut microbiome study found that rats fed with IDT dramatically modified the gut microbial species at the family level, such as suppressing the increase abundance of Proteobacteria and Firmicutes induced by HFD. HIDT significantly boosted the relative composition of beneficial bacterium Akkermansia and Rikenellaceae_RC9_gut_group and decreased the relative abundance of the harmful bacterium Ruminococcaceae_UCG-005 and Ruminiclostridium_9,compared to HFD (p <0.01).Correlation analysis between microbiome and animal indicators found that seven genera including Akkermansia,Clostridiales,Lachnospiraceae, Lachnospiraceae_UCG-010,Ruminiclostridium_9,Ruminococaceae-UCG-005. and Ruminocuccus_1 were found as potential biomarkers that were strongly correlated with oxidative stress and metabolism genes.For instance,Ruminococcaceae_UCG-005

                     （The potential intervention mechanism of instant dark tea (IDT) on glucose and lipid metabolism abnormalities in high-fat fed rats）

            （Effects of instant dark tea (IDT) on body weight, blood lipid and blood glucose of rats fed with high fat）

                                                     (Effects of Instant dark tea (IDT) on liver morphology and H&E staining of high-fat rats）

                                                                                     （Composition (part) of intestinal flora at genus level）

references：

[1] Everard A ,  Belzer C ,  Geurts L , et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity[J]. Proceedings of the National Academy of Sciences of the United States of America, 2013, 110(22):9066-9071.

[2] Depommier C ,  Everard A ,  Druart C , et al. Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study[J]. Nature Medicine, 2019, 25(7):1096.