title: Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules.
abstract: 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'-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'-O-methyl quercetin) and tamarixetin (4'-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 cmax values six times higher after ingestion of 130 mg quercetin by quercetin-enriched cereal bars than after ingestion by quercetin capsules. In contrast, tmax did not differ significantly between the two treatments. The cmax 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.
authors.affiliation: Department of Nutrition and Food Science, Nutritional Physiology, University of Bonn, Endenicher Allee 11-13, Bonn, Germany. s.egert@uni-bonn.de
authors.forename: Sarah
authors.initials: S
authors.lastname: Egert
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wolffram
authors.forename: Beate
authors.initials: B
authors.lastname: Schulze
authors.forename: Peter
authors.initials: P
authors.lastname: Langguth
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Hubbermann
authors.forename: Karin
authors.initials: K
authors.lastname: Schwarz
authors.forename: Berit
authors.initials: B
authors.lastname: Adolphi
authors.forename: Anja
authors.initials: A
authors.lastname: Bosy-Westphal
authors.forename: Gerald
authors.initials: G
authors.lastname: Rimbach
authors.forename: Manfred James
authors.initials: MJ
authors.lastname: Müller
mesh_terms: D000328:Adult; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D000975:Antioxidants / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002214:Capsules; D018592:Cross-Over Studies; D019587:Dietary Supplements / Q000032:analysis*; D004187:Disaccharides / Q000097:blood; D002523:Edible Grain / Q000737:chemistry*; D057140:Fast Foods / Q000032:analysis*; D005260:Female; D005527:Food, Fortified / Q000032:analysis*; D006801:Humans; D007700:Kinetics; D009753:Nutritive Value; D010865:Pilot Projects; D011208:Powders; D011794:Quercetin / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D000975:Antioxidants; D002214:Capsules; D004187:Disaccharides; D011208:Powders; C047368:3-methylquercetin; C508967:tamarixetin; D011794:Quercetin