Mechanism of nonshivering thermogenesis activation by pepper and cinnamon extracts

A previous study from our laboratory established the thermogenic potential of pepper and cinnamon extracts. In this study we tried to further understand the mechanism by which the two spices were exhibiting their thermogenic potential by studying the expression level of specific genes, (UCP1, PRDM16, PGC1α and CPTC1) in specific organs. We also measured the levels of norepinephrine (NOR), free fatty acids (FFA), thyroid hormone levels in circulation and lastly measured the shivering intensity in skeletal muscles of cold exposed rats. We observed that treatment with the spices increased the expression levels of studied genes in specific organs. The up-regulated genes were indicative of increased BAT content and activity, browning of WAT and an overall increase in metabolism. We also noted an increased NOR, FFA and thyroid hormone levels in circulation. Shivering intensity in muscles of cinnamon treated animals decreased more in comparison to pepper. Based on our results, we concluded that the two spices increase the overall heat generation in cold exposed animals by increasing BAT activity, BAT content, causing browning of WAT and increasing oxidative metabolism. Further understanding of this orchestered response might throw new light into the existing knowledge of regulation of the thermogenic process.