Cinnamon extract exhibits insulin‐like and independent effects on gene expression in adipocytes

Abstract

Cinnamon is beneficial to people with insulin resistance due in part to the insulin‐like activity of the cinnamon extract (CE). Molecular effects of CE are limited. This study tested the hypothesis that CE has insulin‐like and insulin‐independent effects at the molecular level. Quantitative real‐time PCR was used to evaluate CE effects on the expression of 43 genes coding for the glucose transporter (GLUT) family, insulin‐signaling components, adipokines, pro‐inflammatory cytokines and anti‐inflammatory tristetraprolin (TTP) family in mouse 3T3‐L1 adipocytes. CE (100 mg/L) increased GLUT1 mRNA levels by 2‐7 fold after 2‐16 h treatment. CE increased TTP mRNA levels by up to 10‐fold. Vascular endothelial growth factor (VEGF) mRNA levels were decreased 40‐50% by CE from 0.5‐4 h. CE decreased the expression of most genes encoding insulin signaling pathway proteins. Insulin‐like effects of CE included rapid induction of TTP mRNA, and reduction of mRNA for VEGF and components of the insulin‐signaling pathway. Insulin‐independent effects of CE included sustained increases in GLUT1 and TTP expression. These results demonstrated that CE regulated multiple gene expression in mouse adipocytes and suggested that the health benefits of cinnamon are due to both its insulin‐like and insulin‐independent effects (Supported in part by USDA‐ARS Human Nutrition Research Program).