ABSTRACT
Quercetin and myricetin are avonols, a class of avonoid, and are abundant in plant as secondary metabolites. Quercetin and quercetin glycosides are known to have many bene…cial e¬ects on health [1,2]. Myricetin, which has an additional hydroxyl group at 5′ position of B-ring in quercetin, is also known to be abundantly present in tea, wine, and grapes [3] and is known to have some physiological e¬ects, such as the improvement of glucose intolerance [4,5] and cancer prevention [6,7]. Intestinal absorption of quercetin and quercetin-3O-glucoside has been well-studied in animals and humans [8-10], and it has been reported that quercetin-3-O-glucoside is hydrolyzed into aglycone in the small intestinal lumen by lactase-phloridine hydrolase, then transported into the intestinal epithelial cells, where it is conjugated as quercetin glucuronides or sul…des, before release into the mesenteric blood [11,12]. Another reported mechanism suggests that quercetin-3-O-glucoside is absorbed as a glycoside via the sodium-dependent glucose transporter 1 (SGLT1) [13]. However, there
Contents
35.1 Introduction 487 35.2 Materials and Methods 488
35.2.1 Chemicals 488 35.2.2 Animals 489 35.2.3 Absorption by Ligated Jejunum and Ileum
of Anesthetized Rats 489 35.2.4 Sample Treatment for Measurement of Quercetin Derivatives 489 35.2.5 Quanti…cation of Myricetin Derivatives by Liquid
Chromatography/Mass Spectrometry 490 35.2.6 Statistics 490
35.3 Results 490 35.4 Discussion 493 References 495
is little information on intestinal absorption of myricetin and myricetin glycosides. One report describes the transport of myricitrin (myricetin 3-O-α-lrhamnoside) via the paracellular pathway in Caco-2 monolayer, a model of the intestinal epithelium [14].
