Black-fruited chokeberries (Aronia melanocarpa), growing mainly in the Central and Eastern European countries, have health benefits due to the high concentrations of polyphenolic compounds. However, a strong bitter taste of chokeberries limits its usage as functional food. We hypothesized that the fermented A. melanocarpa with a reduced bitter taste would improve insulin sensitivity and/or ameliorate weight gain induced by high-fat diet (HFD) in male C57BL/6J mice. The mice were administered with HFD together with the 100 mg/kg of natural A. melanocarpa (T1) or the fermented A. melanocarpa (T2) for 8 weeks. The treatment with T2 (100 mg/kg body weight, p.o.) markedly attenuated the weight gain and the increase in serum triglyceride level induced by HFD. The T2-treated group had better glucose tolerance and higher insulin sensitivity as measured by oral glucose tolerance test and intraperitoneal insulin tolerance test in comparison to the T1-treated group. Phytochemical analysis revealed that the main constituents of T2 were cyanidin-3-xyloside and 1-(3',4'-dihydroxycinnamoyl)cyclopenta-2,3-diol, and the content of cyanidin glycosides (3-glucoside, 3-xyloside) was significantly reduced during the fermentation process. From the above results, we postulated that antiobesity effect of black chokeberry was not closely correlated with the cyanidin content. Fermented chokeberry might be a viable dietary supplement rich in bioactive compounds useful in preventing obesity.
Keywords: aronia berries; fermentation; glucose intolerance; high-fat diet-induced obesity; insulin resistance; phytochemical analysis.