Bioactivation of flavonoid diglycosides by chicken cecal bacteria

Flavonoids, the potent antioxidant and anti-inflammatory plant compounds, require deglycosylation for absorption across the intestine. Intestinal bacteria are indispensable for the hydrolysis of flavonoid diglycosides. We isolated, for the first time, three anaerobic Lactobacillus-like strains designated as MF-01, MF-02 and MF-03 from the cecum of chicken capable of converting flavonoid diglycosides into bioactive aglycones. All the isolated strains were found to be active in the conversion of quercetin-3-rhamnoglucoside (rutin) and hesperetin-7-rhamnoglucoside (hesperidin) into their aglyconic forms. No metabolites were detected after the fermentation tests with naringenin-7-rhamnoglucoside (naringin). The degradation rates of flavonoids and influence of different carbon sources, following incubation with isolated strains, were also monitored. Overall maltose resulted in rapid degradation of flavonoids. However, when organic acids (lactate, acetate, butyrate or propionate) were added to the basal medium as carbon source, flavonoid degradation was completely inhibited. Using consortium of three isolated strains, fructooligosaccharide (10 g L(-1)) supplementation was found to be imperative for preserving aglycone hesperitin while organic acids supplementation (10 g L(-1)) to the fermentation medium resulted in rapid degradation of hesperitin indicating that the metabolic fate of flavonoids may be related to the gut metabolic behavior. Butyrate and propionate also suppressed rutin deglycosylation by the consortium.