Regioselective formation of quercetin 5-O-glucoside from orally administered quercetin in the silkworm, Bombyx mori

Larvae of Bombyx mori absorb quercetin from their food and metabolize it to quercetin 5-O-glucosides, which are rare in plants. The first step of in the quercetin metabolism is catalyzed by a UDP-glucosyl transferase (UGT) with a regiospecificity for the C-5 position of quercetin in the midgut tissue.