Abstract: This study was undertaken to investigate the effects of caffeine and chlorogenic acid (CGA), two major components in coffee, on body weight, lipid accumulation and the expression of lipid metabolism-related genes in obese mice fed a high-fat diet. With this aim, 50 female ICR mice were randomly divided into five groups: control, high-fat diet (HFD), caffeine, CGA, and caffeine + CGA groups. The animals in the experimental groups were given drinking water supplemented with 0.05% caffeine, 0.2% CGA and 0.05% caffeine + 0.2% CGA, respectively for 14 consecutive weeks. Body weight was measured daily during the experimental period. Visceral organs and intraperitoneal adipose tissues (IPAT) were harvested and weighed at the end of the experimental period, and blood samples from the heart were collected for measurement of serum glucose and lipid concentrations and liver lipid levels. The mRNA expression levels of lipid metabolism-related genes in liver (AMPK, HMG-CoAr, FASN, and ACO) were determined by real time-quantitative PCR (RT-qPCR). Compared with the HFD group, caffeine + CGA remarkably reduced body weight gain and IPAT weight. The serum glucose and TC levels were decreased significantly by caffeine, and caffeine + CGA. The serum low-density lipoprotein cholesterol (LDL-C) concentration was remarkably lower in mice administrated with CGA, while CGA could result in an increase in serum free fatty acid concentration. Caffeine alone and in combination with CGA remarkably reduced the liver total cholesterols (TC) and triglyceride (TG) levels, significantly increased the mRNA expression of AMPK and significantly reduced the mRNA expression of FASN in liver. A significant up-regulation in the mRNA expression of ACO and a significant down-regulation in the mRNA expression of HMG-CoAr in liver were observed for all three experimental groups. Conclusions: The anti-obesity effects of caffeine + CGA may be achieved through regulating the mRNA expression of lipid metabolism-related genes in liver, modulating serum and liver lipid levels in, and inhibiting body weight gain and fat accumulation in mice in a synergistic manner.

Key words: caffeine, chlorogenic acid, fat accumulation, lipid metabolism, mRNA expression