Catechins and Caffeine Promote Lipid Metabolism and Heat Production Through the Transformation of Differentiated 3T3-L1 Adipocytes from White to Beige Adipocytes.

To elucidate effects of catechins and caffeine on lipid metabolism in adipocytes and identify the mechanism of action, differentiated 3T3-L1 adipocytes were incubated in culture media containing catechins at 1, 2.5, 5, and 10 µg/mL and caffeine at 50 and 100 µg/mL, singly or in combination, for 8 days. Intracellular lipid accumulation and glycerol-3-phosphate dehydrogenase activity were strongly suppressed by catechins and caffeine combination treatment. The mRNA expression of PPARɤ, GLUT4, HSL, UCP-1, and TMEM26 were significantly increased in the combined groups. These findings suggest that the combined treatment inhibited lipid synthesis and improved lipid metabolism in adipocytes. Moreover, it was indicated that the differentiated 3T3-L1 adipocytes could be transformed from white adipocytes to beige-like adipocytes by catechins and caffeine, and accordingly that this transformation could promote calorigenic action. PRACTICAL APPLICATION: In this study, we revealed that the combined treatment of catechins and caffeine inhibited lipid synthesis and improved lipid metabolism in adipocytes. Moreover, the treatment may contribute to the transforming from white adipocytes to beige-like adipocytes, which could strongly promote calorigenic action.