Related Experiment Video
Updated: Feb 5, 2026

Bimolecular Fluorescence Complementation BiFC Assay for Protein-Protein Interaction in Onion Cells Using the Helios Gene Gun
Published on: June 12, 2010
Bioavailability of Quercetin from Onion Extracts after Intraruminal Application in Cows
Silvia Wein1, Birgit Beyer1, Benno F Zimmermann2
1Institute of Animal Nutrition and Physiology , Christian-Albrechts-University of Kiel , Hermann-Rodewald-Straße 9 , 24118 Kiel , Germany.
Abstract:
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.
Related Concept Videos
Bioavailability: Overview
Bioavailability: Overview
Bioavailability Study Design: Absolute Versus Relative Bioavailability
Bioavailability Enhancement: Determination and Conceptual Approaches in Overcoming Bioavailability Problems
Bioavailability: Influencing Factors
Measurement of Bioavailability: Pharmacokinetic Methods

