Volume 98, Issue 6, June 2015, Pages 3906–3917
Bioavailability of the flavonol quercetin in neonatal calves after oral administration of quercetin aglycone or rutin
Abstract
Polyphenols,
such as flavonoids, are secondary plant metabolites with potentially
health-promoting properties. In newborn calves flavonoids may improve
health status, but little is known about the systemically availability
of flavonoids in calves to exert biological effects. The aim of this
study was to investigate the oral bioavailability of the flavonol
quercetin, applied either as quercetin aglycone (QA) or as its
glucorhamnoside rutin (RU), in newborn dairy calves. Twenty-one male
newborn German Holstein calves were fed equal amounts of colostrum and
milk replacer according to body weight. On d 2 and 29 of life, 9 mg of
quercetin equivalents/kg of body weight, either fed as QA or as RU, or
no quercetin (control group) were fed together with the morning meal.
Blood samples were taken before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 12,
24, and 48 h after feed intake. Quercetin and quercetin metabolites
with an intact flavonol structure (isorhamnetin, tamarixetin, and
kaempferol) were analyzed in blood plasma after treatment with
glucuronidase or sulfatase by HPLC with fluorescence detection. Maximum
individual plasma concentration was depicted from the
concentration-time-curve on d 2 and 29, respectively. Additional blood
samples were taken to measure basal plasma concentrations of total
protein, albumin, urea, and lactate as well as pre- and postprandial
plasma concentrations of glucose, nonesterified fatty acids, insulin,
and cortisol. Plasma concentrations of quercetin and its metabolites
were significantly higher on d 2 than on d 29 of life, and
administration of QA resulted in higher plasma concentrations of
quercetin and its metabolites than RU. The relative bioavailability of
total flavonols (sum of quercetin and its metabolites isorhamnetin,
tamarixetin, and kaempferol) from RU was 72.5% on d 2 and 49.6% on d 29
when compared with QA (100%). Calves fed QA reached maximum plasma
concentrations of total flavonols much earlier than did RU-fed calves.
Plasma metabolites and hormones were barely affected by QA and RU
feeding in this experiment. Taken together, orally administrated QA
resulted in a greater bioavailability of quercetin than RU on d 2 and
29, respectively, and quercetin bioavailability of quercetin and its
metabolites differed markedly between calves aged 2 and 29 d.
Key words
- bioavailability;
- calf;
- flavonoid;
- quercetin;
- rutin
Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
