Xinhe Yang^{1, 2}, Zhonghua Liu^{1, 3,}, Jianan Huang^{2, 4}, Caiqin Qin⁵, Qingli Mao^{1, 2}, Qin Li^{2, 4}

Pu-erh tea, a well-known tea from ancient times, was originally produced in the Yunnan province of China. Theabrownin of pu-erh tea was successfully separated into six fractions by using a sephadex LH-20 column. A previous study showed that the inhibition of α-glycosidase and pancreatic lipase activities was enriched in theabrownin fraction 5 (F5). Here, the effects of F5 on the proliferation and differentiation of 3T3-L1 preadipocytes were investigated. Results showed that F5 suppressed 3T3-L1 preadipocyte proliferation and during 3T3-L1 preadipocyte differentiation, F5 dose-dependently promoted lipid accumulation and significantly decreased the expression of PPARγ2, PTP1B mRNA and protein and Glut4 protein as well as increased the expression of Glut4 mRNA. The findings suggested that F5 act to maintain a reasonable lipid metabolism balance by regulating the mRNA and protein expression of PPARγ2, and allow the activation of insulin receptor proteins to promote Glut4 translocation to the cell membrane and glucose intake by decreasing PTP1B protein expression. Together, these activities may improve Insulin resistance (IR) and prevent metabolic syndrome, which is important for establishing a basis for the development of F5 into a functional food.

pu-erh tea, theabrownin, fraction 5, 3T3-L1 preadipocyte, PPARγ2, PTP1B, Glut4