Effect of Free and Bound Polyphenols from Rose Roxburghii Tratt Distiller's Grains on Moderating Fecal Microbiota

Abstract

As the main wine by-products, Rosa roxburghii Tratt distiller’s grains (R. roxburghii DGs) were always be discarded, while the remained rich polyphenols were neglected which maintained important functional value. In this study, free and bound polyphenols were extracted from R. roxburghii DGs and the compositions, antioxidant activities, as well as modulations of fecal microbiota and short chain fatty acids (SCFAs) were evaluated. Results revealed that free polyphenols had higher concentrations and better antioxidant activities than bound polyphenols, in addition, both of which were enriched in flavonoids, especially catechin (free polyphenols: 145.30 – 304.66 mg/g; bound polyphenols: 25.10 – 25.34 mg/g). Fecal microbiota community structure and SCFAs concentration were regulated by free and bound polyphenols. Moreover, quercetin, catechin, kaempferol, cyanidin and baicalin were keystone individual phenolic compounds responsible for antioxidant activity and microbiota modulation. This study suggests that R. roxburghii DGs are a promising source for natural antioxidants and prebiotic foods.

Keywords: Rosa roxburghii Tratt distiller's grains, Polyphenols, antioxidant activity, Fecal microbiota, Short chain fatty acids