| Summary: | Polyphenols have been reported to offer protection against the development of chronic diseases such as cardiovascular diseases or diabetes. The purpose of this study was to investigate the possible effect of different extracts rich in polyphenols on diet-induced adiposity and to elucidate the mechanisms involved in this effect through nutrigenomic and epigenetic studies in rats. We first characterized different rat obesity models induced by a high-fat diet, high-fat-sucrose (HFS) diet and a high-sucrose diet. The results revealed that HFS intake led to the establishment of a good obesity model to evaluate the biological activity of plant extracts. Then, a screening of different polyphenolic extracts for anti-obesity properties was conducted in rats fed a HFS diet. Extracts rich in polyphenols from apple, cinnamon, hamamelis and birch prevented body weight gain promoted by HFS intake, while apple and cinnamon extracts reduced adiposity gain. Since apple polyphenolic (AP) extract displayed the most outstanding properties, we seeked to study the mechanisms involved in its anti-obesity action. AP supplementation prevented HFS diet-induced hyperglycemia, hyperleptinemia, insulin resistance, glucose tolerance and adipocyte hypertrophy. These findings were accompanied by a prevention of the reduced lipolytic response induced by HFS diet and changes in the expression of adipocyte genes involved in adipogenesis, lipolysis, fatty acid oxidation and glycerol release. Furthermore, some of these genes could be subjected to epigenetic regulation, since changes in DNA methylation patterns were observed in AP-supplemented rats. In summary, we have shown that AP could be a useful functional food ingredient for the prevention of diet-induced obesity and its related complications.
|
|---|