Bioavailability and metabolism of the flavonol quercetin in the pig

Ader, Peter

doi:10.1016/s0891-5849(00)00195-7

Cited by 245 publications

(206 citation statements)

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“…This finding is in accordance with our previous human kinetic study (15) and has also been found in pigs (27,28) . However, in contrast to mice and rats, in which nearly one-half of the absorbed amount of quercetin is methylated to isorhamnetin (29 -32) , the proportion of the methylated derivatives in human and pig plasma is rather low (approximately 15 -20 % of total plasma flavonols).…”

Section: Discussionsupporting

confidence: 94%

Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules

et al. 2011

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The flavonol quercetin, is one of the major flavonoids found in edible plants. The bioavailability of quercetin in humans may be influenced by the food matrix in which it is consumed as well as by its chemical and physical form. The objective of the present study was to investigate the biokinetics of quercetin from quercetin-enriched cereal bars and quercetin powder-filled hard capsules. In a randomised, single-blinded, diet-controlled cross-over study, six healthy women aged 22 -28 years took a single oral dose of approximately 130 mg quercetin equivalents from either quercetin-enriched cereal bars (containing 93·3 % quercetin aglycone plus 6·7 % quercetin-4 0 -glucoside) or quercetin powder-filled hard capsules (100 % quercetin aglycone). Blood samples were drawn before and after quercetin administration over a 24 h period. The concentrations of quercetin and its monomethylated derivatives, isorhamnetin (3 0 -O-methyl quercetin) and tamarixetin (4 0 -O-methyl quercetin), were measured by HPLC with fluorescence detection after plasma enzymatic treatment. The systemic availability as determined by comparing the plasma concentration -time curves of quercetin was found to be five times and the c max values six times higher after ingestion of 130 mg quercetin by quercetin-enriched cereal bars than after ingestion by quercetin capsules. In contrast, t max did not differ significantly between the two treatments. The c max values for isorhamnetin and tamarixetin were four and nine times higher after ingestion of quercetin by quercetin-enriched cereal bars than after ingestion by quercetin capsules. In conclusion, quercetin from quercetin-enriched cereal bars is significantly more bioavailable than from quercetin powder-filled hard capsules.Key words: Quercetin: Bioavailability: Onions: Human studies Quercetin (3,3 0 ,4 0 ,5,7-pentahydroxyflavone) is one of the major flavonoids, ubiquitously distributed in edible plants (1) . Epidemiological studies, together with data from animal models and some clinical trials, may suggest a role of flavonoids in general and of quercetin in particular in the prevention of CVD and other age-related chronic diseases (2) . In plasma, quercetin is found in the form of glucuronidated, sulphated and methylated derivatives (3) . Rich sources of dietary quercetin are onions, unpeeled apples, berries, citrus fruits, tea (Camellia sinensis) and red wine (1) . Daily dietary intake of the flavonol quercetin varies considerably. In Western populations, crude estimates of mean dietary intake appear to be 10 -100 mg/d (1,4) . In some countries, quercetin is available as a dietary supplement with daily doses of 200-1200 mg quercetin (manufacturers' recommendations). In addition, quercetin may be used as a nutraceutical for functional foods within a concentration range of 0·008 -0·5 % or 10 -125 mg/serving (5) . Rather high concentrations of * Corresponding author: S. Egert, fax þ49 228 733217, email s.egert@uni-bonn.de Abbreviations: AUC, area under plasma concentration -time curve; c max , ...

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Section: Discussionsupporting

confidence: 94%

Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules

et al. 2011

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“…Furthermore, parthenogenetic activation is relevant to cloning research because artificial oocyte activation is an essential component of nuclear transfer protocols [19]. The concentrations of quercetin used in this study (1,10, and 50 μg/mL) were selected based on previous results from a study of porcine granulosa cells [28]. In this study, 50 μg/mL quercetin was found to inhibit progesterone production, modify estradiol-17β production, and interfere with angiogenesis in granulosa cells by inhibiting vascular endothelial growth factor production, implying that quercetin may have a negative influence on ovarian physiology.…”

Section: Discussionmentioning

confidence: 99%

“…A relationship has been demonstrated between the free radical scavenging activity and anti-carcinogenic and anti-inflammatory properties of quercetin [17,32]. Studies have been performed to evaluate the physiological functions and biological activities of quercetin in humans and animals [1,13]. However, there is limited information available on the effect of quercetin on oocyte maturation and embryonic development in pigs.…”

Section: Introductionmentioning

confidence: 99%

Quercetin Improves In Vitro Development of Porcine Oocytes by Decreasing Reactive Oxygen Species Levels.

Kang

Kwon

Park

et al. 2011

Biology of Reproduction

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Quercetin is a plant-derived flavonoid found in fruits or vegetables that has antioxidant properties and acts as a free radical scavenger. We investigated the effects of quercetin on porcine oocyte nuclear maturation and embryonic development after parthenogenetic activation. We then evaluated the antioxidant activities of quercetin by measuring reactive oxygen species (ROS) levels in matured oocytes. Immature oocytes were untreated or treated with 1, 10, and 50 μg/mL quercetin during in vitro maturation (IVM). Quercetin treatment did not improve oocyte nuclear maturation, but significantly higher blastocyst rates (p ＜ 0.05) of parthenogenetically activated oocytes were achieved when the IVM medium was supplemented with an adequate concentration of quercetin (1 μg/mL). However, cleavage rates and blastocyst cell numbers were not affected. Oocytes treated with 1 or 10 μg/mL quercetin had significantly lower (p ＜ 0.05) levels of ROS than the control and group treated with the highest concentration of quercetin (50 μg/mL). Moreover, this highest concentration was detrimental to oocyte nuclear maturation and blastocyst formation. Based on our findings, we concluded that exogenous quercetin reduces ROS levels during oocyte maturation and is beneficial for subsequent embryo development.

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“…The supernatant was removed, diluted with water (1 : 1) and injected onto the HPLC column (injection volume 50 ml). Hydrolysis of glucuronide and sulphate conjugates of quercetin in the plasma or bile was performed as described by Ader et al (2000). In short, b-glucuronidase solution (500 U in 0.1 M ammonium acetate pH 6.8) also containing sulphatase was added to an aliquot (0.1 ml) of biofluid (acidified with 20 ml of 0.5 M acetic acid).…”

Section: Sample Preparation and Hplc Analysismentioning

confidence: 99%

Characterisation of metabolites of the putative cancer chemopreventive agent quercetin and their effect on cyclo-oxygenase activity

et al. 2004

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Quercetin (3,5,7,3 0 ,4 0 -pentahydroxyflavone) is a flavone with putative ability to prevent cancer and cardiovascular diseases. Its metabolism was evaluated in rats and human. Rats received quercetin via the intravenous (i.v.) route and metabolites were isolated from the plasma, urine and bile. Analysis was by high-performance liquid chromatography and confirmation of species identity was achieved by mass spectrometry. Quercetin and isorhamnetin, the 3 0 -O-methyl analogue, were found in both the plasma and urine. In addition, several polar peaks were characterised as sulphated and glucuronidated conjugates of quercetin and isorhamnetin. Extension of the metabolism studies to a cancer patient who had received quercetin as an i.v. bolus showed that (Quercetin removed) isorhamnetin and quercetin 3 0 -O-sulphate were major plasma metabolites. As a catechol, quercetin can potentially be converted to a quinone and subsequently conjugated with glutathione (GSH). Oxidation of quercetin with mushroom tyrosinase in the presence of GSH furnished GSH conjugates of quercetin, two mono-and one bis-substituted conjugates. However, these species were not found in biomatrices in rats treated with quercetin. As cyclo-oxygenase-2 (COX-2) expression is mechanistically linked to carcinogenesis, we examined whether quercetin and its metabolites can inhibit COX-2 in a human colorectal cancer cell line (HCA-7). Isorhamnetin and its 4 0 -isomer tamarixetin were potent inhibitors, reflected in a 90% decrease in prostaglandin E-2 (PGE-2) levels, a marker of COX-2 activity. Quercetin was less effective, with a 50% decline. Quercetin 3-and 7-O-sulphate had no effect on PGE-2. The results indicate that quercetin may exert its pharmacological effects, at least in part, via its metabolites. Naturally occurring flavonoids in the diet are associated with several beneficial health effects and understanding the mechanisms underlying these effects has become the focus of much research. Quercetin (3,5,7,3 0 ,4 0 -pentahydroxyflavone, for structure see Figure 1) is a prime example of such a flavonoid. Its glycosylated form occurs in kale, French beans, broccoli, apples and especially in onions, with an abundance as high as a quarter to half a gram per kg (Hertog et al, 1992). On ingestion with the diet, quercetin glycosides are rapidly hydrolysed to generate quercetin.Epidemiological evidence links diets rich in quercetin with decreased incidence of cardiovascular and neoplastic diseases

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Bioavailability and metabolism of the flavonol quercetin in the pig

Cited by 245 publications

References 44 publications

Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules

Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules

Quercetin Improves In Vitro Development of Porcine Oocytes by Decreasing Reactive Oxygen Species Levels.

Characterisation of metabolites of the putative cancer chemopreventive agent quercetin and their effect on cyclo-oxygenase activity

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