An extract of chokeberry attenuates weight gain and modulates insulin, adipogenic and inflammatory signalling pathways in epididymal adipose tissue of rats fed a fructose-rich diet

Chokeberries are a rich source of anthocyanins, which may contribute to the prevention of obesity and the metabolic syndrome. The aim of the present study was to determine if an extract from chokeberries would reduce weight gain in rats fed a fructose-rich diet (FRD) and to explore the potential mechanisms related to insulin signalling, adipogenesis and inflammatory-related pathways. Wistar rats were fed a FRD for 6 weeks to induce insulin resistance, with or without chokeberry extract (CBE) added to the drinking-water (100 and 200 mg/kg body weight, daily: CBE100 and CBE200). Both doses of CBE consumption lowered epididymal fat, blood glucose, TAG, cholesterol and LDL-cholesterol. CBE consumption also elevated plasma adiponectin levels and inhibited plasma TNF-α and IL6, compared with the control group. There were increases in the mRNA expression for Irs1 , Irs2 , Pi3k , Glut1 , Glut4 and Gys1 , and decreases in mRNA levels of Gsk3β. The protein and gene expression of adiponectin and Pparγ mRNA levels were up-regulated and Fabp4 , Fas and Lpl mRNA levels were inhibited. The levels of gene expression of inflammatory cytokines, such as Il1β , Il6 and Tnfα were lowered, and protein and gene expression of ZFP36 (zinc finger protein) were enhanced in the epididymal adipose tissue of the rats that consumed the CBE200 extract. In summary, these results suggest that the CBE decreased risk factors related to insulin resistance by modulating multiple pathways associated with insulin signalling, adipogenesis and inflammation.