Comparative Analysis of Hypoglycemic and Lipid-lowering Efficacy of Large-leaf Yellow Tea Made from Different Tea Cultivars
Large-leaf yellow tea is a unique tea in China.It is made from fresh leaves of four or five leaves with one bud.It has unique quality of yellow dry tea appearance,yellow soup and yellow infused leaves,and has significant hypo-glycemic and lipid-lowering effects.However,there are few comparative studies on the effects of its hypoglycemic and lipid-lowering components.Therefore,in this study,13 different tea cultivars were selected to make dry tea according to the standard process of large-leaf yellow tea.The inhibition rate of α-glucosidase activity and the effect on the differentiation of 3T3-L1 cells were used to compare their in vitro hypoglycemic and lipid-lowering effects.The contents of biochemical components in the water extract were further determined and multivariate statistical analysis was performed to explore the key hypoglycemic and lipid-lowering substances of large-leaf yellow tea.The results show that'Huangjingui'had the best hypoglycemic effect,and the IC50 value was 185.17 μg/mL.The tea cultivar with the best lipid-lowering effect was'Shidacha No.1'.After tea treatment,the total cholesterol content in 3T3-L1 preadipocytes decreased by 78.8 percentage points compared with the control group,and the triglyceride content decreased by 93.5 percentage points compared with the control group.The results of biochemical components of large-leaf yellow tea made from different cultivars show that the content of tea polysaccharide in'Wancha 91'was the highest(5.59％),while tea polysaccharide content of'Chanong 98'was only 3.38％.The results of PCA analysis show that'Jinjizhong'and'Shidacha No.1'were significantly different from other cultivars in biochemical composition,with the total catechin content being the main contributor.The results of correlation analysis show that tea polyphenols and tea polysaccharides may be the main active substances affecting the hypoglycemic effect of large-leaf yellow tea,while total catechins and tea poly-saccharides are the substances that affect the lipid-lowering effect of large-leaf yellow tea.In summary,tea polysac-charides may be the main active substances that affect the hypoglycemic effect of different tea cultivars,while free amino acids and theanine are the substances that affect the lipid-lowering effect.The results of this study provided a theoretical basis for the screening of health-oriented large-leaf yellow tea varieties.
万方数据
维普
