关键词: 白茶, 红茶, 绿茶, 高脂饮食, 预防肥胖, 安全性

Abstract: Objective: To evaluate and compare the anti-obesity efficacy of white, green and black tea extract (GTE, BTE and WTE) and white tea infusion (WTI) in mice with high-fat diet-induced obesity and to investigate their mechanisms of action. Methods: For this study, GTE, BTE and WTE were prepared from Shoumei green tea, Bailin Gongfu black tea and Anji Bai white tea, respectively. C57BL/6J mice were fed on a high-fat diet or a normal diet supplemented with WTE, GTE, BTE, WTI or distilled water. After 8 weeks of feeding, body mass, wet mass of adipose tissue, subcutaneous adipocyte diameter and serum lipid levels of mice were determined. The pathological changes of liver and adipose tissues were observed. The differential expression profiles of lipid metabolism-related genes in liver tissues of mice were also determined by real-time fluorescence quantitative polymerase chain reaction. Results: GTE and WTE reduced body mass gain in high-fat diet-fed rats by 22.49% and 21.23%, respectively, and they also significantly decreased the wet mass of adipose tissue and subcutaneous adipocyte diameter (P < 0.05). BTE reduced body mass gain by 9.03%, but had no significant effect on the wet mass of adipose tissue or subcutaneous adipocyte diameter (P > 0.05). The BTE, WTI and model control groups showed hepatic steatosis, whereas the liver of mice in the GTE and WTE groups was kept in good condition. GTE and WTE could improve lipid metabolism disorder induced by high-fat diet at the transcription level. Conclusion: At the dosages used in this study, hepatotoxicity and growth inhibition have not been found in the WTE, GTE and BTE groups. GTE and WTE can regulate the transcription and expression of lipid metabolism-related genes, inhibit fatty acid synthesis and enhance liver fatty acid oxidation, thus effectively preventing the occurrence of obesity and fatty liver in high-fat diet-fed mice. The effect of GTE is slightly better than that of WTE (P > 0.05). However, BTE has little anti-obesity efficacy and no protective effect on the liver. In addition, WTI can not prevent the occurrence of obesity and fatty liver in high-fat diet-fed mice.

Key words: white tea, black tea, green tea, high-fat diet, anti-obesity, safety