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Bioavailability of Quercetin from Onion Extracts after Intraruminal Application in Cows
- Wein, Silvia, Beyer, Birgit, Zimmermann, Benno F., Blank, Ralf H., Wolffram, Siegfried
- Journal of agricultural and food chemistry 2018 v.66 no.39 pp. 10188-10192
- bioavailability, blood sampling, body weight, bulbs, cows, fistula, fluorescence, glucosides, high performance liquid chromatography, isorhamnetin, kaempferol, metabolites, onions, quercetin, rumen, rutin
- The aim of the present study was to investigate the bioavailability of quercetin from onion bulb (OB) and onion skin (OS) extracts in ruminants. Three non-lactating cows equipped with a permanent rumen fistula intraruminally received equimolar amounts of quercetin as either aglycone, rutin, or OB or OS extract, respectively, at a dose of 50 mg of quercetin equivalents/kg of body weight. Blood samples were drawn before and frequently within the 24 h period after application of the respective substance. Quercetin and quercetin metabolites with an intact flavonol structure (kaempferol, isorhamnetin, and tamarixetin) were analyzed in plasma samples by high-performance liquid chromatography with fluorescence detection. All quercetin sources administered resulted in a fast increase of the plasma concentrations of quercetin and total flavonols (sum of quercetin and its metabolites), followed by a rapid decline, whereby significant higher concentrations occurred with OB extract and rutin compared to quercetin aglycone and OS extract, respectively. The results clearly demonstrate a higher systemic availability of quercetin from OB extract and rutin. Taken together, OB extract with a high content of quercetin glucosides is an interesting source for the application of quercetin to ruminants.