BIOAVAILABILITY OF RUTIN AND QUERCETIN IN RATS

Quercetin is a powerful antioxidant which is widely distributed in edi ble plants, mainly as glycosides such as rutin, It has been reported t o be absorbed in mammals, but its metabolism needs further investigati on to evaluate its possible physiological effects, We compared the evo lution of the absorption of quercetin and rutin in rats fed with suppl emented diets, Rutin was absorbed more slowly than quercetin because i t must be hydrolysed by the cecal microflora, whereas quercetin was ab sorbed from the small intestine, Conjugated derivatives of quercetin, and its methylated forms isorhamnetin and tamarixetin, were recovered in plasma from rats receiving the two kinds of experimental diets afte r the first meal, but after 10 days, no traces of tamarixetin mere det ected anymore, The rate of elimination of quercetin metabolites seems very low, and high plasma concentrations are easily maintained with a regular supply of quercetin or rutin in the diet. (C) 1997 Federation of European Biochemical Societies.