Black Currant Anthocyanins Attenuate Weight Gain and Improve Glucose Metabolism in Diet-Induced Obese Mice with Intact, but Not Disrupted, Gut Microbiome

Black currant (Ribes nigrum L.) is a rich source of anthocyanins; however, the relationship between their apparently limited bioavailability and significant protection against metabolic pathologies is poorly understood. This study examined the gastrointestinal distribution, of black currant anthocyanins and their phenolic acid metabolites in lean and diet-induced obese mice with healthy and antibiotic disrupted microbiomes. Daily consumption of low or high fat diet supplemented with 1% black currant powdered,extract (32% anthocyanins) for 8 weeks reduced body weight gain and improved glucose metabolism only in Mice with the intact gut microbiome. Administration of antibiotic cocktail resulted in a 16-25-fold increase P < 0.001) in anthocyanin content of feces, and cyanidin-based anthocyanins showed the largest increase in fecal content upon disruption of gut microbiome (92.3 +/- 16.3 vs 4719 +/- 158 mu g/g feces), indicating their high susceptibility to microbial degradation in the gut A. 3-fold enrichment (P < 0.05) in gallic over protocatechuic acid was observed in the jejunum of both intact and antibiotic treated animals, suggesting that this effect was likely independent of their gut microbiome status. Taken together, the data clearly demonstrate that gut microbiome and the type of the anthocyanin aglycone moiety can alter the protective effect of anthocyanins against obesity and associated insulin resistance.