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Comprehensive Analyses of Quercetin Conjugates by LC/MS/MS Revealed That Isorhamnetin-7-O-glucuronide-4′-O-sulfate Is a Major Metabolite in Plasma of Rats Fed with Quercetin Glucosides
- Tanaka, Seiya, Trakooncharoenvit, Aphichat, Nishikawa, Miyu, Ikushiro, Shinichi, Hara, Hiroshi
- Journal of agricultural and food chemistry 2019 v.67 no.15 pp. 4240-4249
- animal models, blood plasma, diet, glucosides, metabolites, quercetin, rats, sulfates, tail, tandem mass spectrometry
- Quercetin glycosides in the diet are absorbed and converted to glucuronides, sulfates, or mixed conjugates of glucuronide and sulfate in plasma. Physiological effects of quercetin conjugates (Q-conjugates) differ depending on the type and position of conjugation. We developed a comprehensive analysis of Q-conjugates, including mixed conjugates, by LC/MS/MS. The whole species of Q-conjugates in tail blood plasma was measured on days 1, 3, and 12 in rats fed a 0.24% quercetin glucoside-containing diet. Twenty-three Q-conjugate molecules were detected, and 16 Q-conjugates among these were quantified using standard compounds. The most abundant metabolite in the plasma was mixed conjugates, comprising isorhamnetin-7-O-glucuronide-4′-O-sulfate, followed by quercetin-7-O-glucuronide-4′-O-sulfate; together, they accounted for 86% of total Q-conjugates on day 12. The profile of quercetin conjugate species did not significantly change during 12 days. The total Q-conjugate molecules quantified by our method was comparable with the total Q-conjugates quantified using an enzymatic deconjugation method.