Abstract
The effects of intestinal microflora on the bioavailability of dietary quercetin in adult mice were studied. The control group was given a casein diet and water ad libitum. The antibiotics-treated group was given a casein diet and water that contained penicillin and streptomycin ad libitum. Fecal beta-glucuronidase activity was significantly greater in the control mice than in the antibiotics-treated mice. The concentrations of quercetin and isorhamnetin, after deconjugation of plasma quercetin metabolites, were significantly greater in the antibiotics-treated mice. The cecal pools of quercetin in the antibiotics-treated mice were significantly greater than those in the control mice. In untreated mice, it may be necessary to reduce the scission of quercetin and quercetin metabolites and greater beta-glucuronidase activity of the microflora might be needed to maintain a higher concentration of plasma quercetin metabolites.
