Rat Gastrointestinal Tissues Metabolize Quercetin ,

Abstract

Quercetin and quercetin glycosides from food or dietary supplements appear in body tissues almost exclusively as glucuronated, sulfated, and methylated quercetin conjugates, suggesting that the in vivo bioactivity of quercetin may be due to its metabolites. In this study, pre- and postabsorptive metabolism of orally ingested quercetin was examined by comparing the metabolite pattern in gastrointestinal (GI) tissues, contents, and internal tissues. F344 rats (n = 6) were fed for 6 wk a diet containing 0.45% quercetin and the metabolite patterns were determined in the tissues and contents of stomach, small intestine, cecum, and colon and in liver, kidney, and plasma using LC-MS/MS. GI contents contained predominantly unmetabolized quercetin at 94-100%, whereas quercetin in GI tissues was present as 11 different sulfated, glucuronated, and methylated metabolites at 32% in stomach, 88% in small intestine, 27% in cecum, and 46% in colon. Quercetin was further metabolized postabsorption and found in liver, kidney, and plasma almost exclusively as sulfated methyl-quercetin glucuronide. The unique pattern of quercetin metabolites in each GI tissue indicates extensive biotransformation before absorption and distribution in rats.

Effect of dietary supplementation of quercetin on antioxidant activity and meat quality of beef cattle

“…Overall acceptance showed higher in control sample. Previous studies explain that intake of dietary quercetin was not stored in muscle directly (de Boer et al, 2005;Graf et al, 2006). In this regard, quercetin does not function directly in meat, while it is metabolized in other organs or digestive tract after consumption, and these are perceived having an influence of sensory of meat .…”

Modulatory effects of rutin on the expression of cytochrome P450s and antioxidant enzymes in human hepatoma cells

“…This bioflavonoid cannot be synthesized by humans or animals; hence, it can be solely obtained from plant products (6). Administration of rutin to rat and rabbit causes the formation of 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid and m-hydroxyphenylacetic acid in urine, and quercetin-3'-O-methyl ether in bile (7). The microflora in lower gut hydrolyzes rutin to quercetin and isoquercetin, which are absorbed by the small intestine wall (8).…”

Effect of Dietary KocetinTMon Meat Quality of Hanwoo Loin

“…According to the sensory score, there were no significant differences among the samples. The current study reveals that the dietary quercetin was not stored in muscle directly (de Boer et al, 2005;Graf et al, 2006). In this regard, quercetin does not work directly in the meat, but, it is metabolized in other organs or digestive tract after absorption, and these are considered having an effect on sensory parameters of meat .…”