Synergistic effects of caffeine and catechins on lipid metabolism in chronically fed mice via the AMP-activated protein kinase signaling pathway.

Abstract

To investigate the mechanistic effects of combined exposure to caffeine and catechins on lipid metabolism in mice. Seventy mice were randomly assigned to seven groups and fed diets containing varying doses of caffeine and catechins for 24weeks. Body weight gain, intraperitoneal adipose tissue (IPAT) weight, serum biochemical parameters, and enzymatic activities, mRNA and protein expression levels of lipid metabolism-related enzymes in the liver and IPAT were analyzed. Following administration of caffeine and catechins, body weight gain, IPAT weight, serum and liver concentrations of total cholesterol and triglyceride were markedly reduced. Lipase activities, including that of AMP-activated protein kinase (AMPK), acyl-CoA oxidase, carnitine acyltransferase, adipose triglyceride lipase, and hormone-sensitive lipase, were significantly upregulated; however, fatty acid synthase (FAS) activity in the liver was suppressed. Combined exposure to caffeine and catechins significantly upregulated mRNA and protein expression levels of lipases while downregulating FAS mRNA expression and protein expression of peroxisome proliferator-activated receptor γ2. The combination of caffeine and catechins regulated the enzymatic activities, mRNA, and protein expression levels of lipid metabolism-related enzymes, resulting in suppression of body weight gain and IPAT weight in mice, potentially through activation of the AMPK signaling pathway. This study indicates that chronic intake of both caffeine and catechins can synergistically contribute to prevention of obesity and lifestyle-related diseases.