title: Ingestion of onion soup high in quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in man: a pilot study.
abstract: Epidemiological data suggest that those who consume a diet rich in quercetin-containing foods may have a reduced risk of CVD. Furthermore, in vitro and ex vivo studies have observed the inhibition of collagen-induced platelet activation by quercetin. The aim of the present study was to investigate the possible inhibitory effects of quercetin ingestion from a dietary source on collagen-stimulated platelet aggregation and signalling. A double-blind randomised cross-over pilot study was undertaken. Subjects ingested a soup containing either a high or a low amount of quercetin. Plasma quercetin concentrations and platelet aggregation and signalling were assessed after soup ingestion. The high-quercetin soup contained 69 mg total quercetin compared with the low-quercetin soup containing 5 mg total quercetin. Plasma quercetin concentrations were significantly higher after high-quercetin soup ingestion than after low-quercetin soup ingestion and peaked at 2.59 (sem 0.42) mumol/l. Collagen-stimulated (0.5 mug/ml) platelet aggregation was inhibited after ingestion of the high-quercetin soup in a time-dependent manner. Collagen-stimulated tyrosine phosphorylation of a key component of the collagen-signalling pathway via glycoprotein VI, Syk, was significantly inhibited by ingestion of the high-quercetin soup. The inhibition of Syk tyrosine phosphorylation was correlated with the area under the curve for the high-quercetin plasma profile. In conclusion, the ingestion of quercetin from a dietary source of onion soup could inhibit some aspects of collagen-stimulated platelet aggregation and signalling ex vivo. This further substantiates the epidemiological data suggesting that those who preferentially consume high amounts of quercetin-containing foods have a reduced risk of thrombosis and potential CVD risk.
authors.affiliation: School of Animal and Microbial Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6AL, UK.
authors.forename: Gary P
authors.initials: GP
authors.lastname: Hubbard
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wolffram
authors.forename: Ric
authors.initials: R
authors.lastname: de Vos
authors.forename: Arnaud
authors.initials: A
authors.lastname: Bovy
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gibbins
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
mesh_terms: D000328:Adult; D003094:Collagen / Q000502:physiology*; D018592:Cross-Over Studies; D004032:Diet; D004187:Disaccharides / Q000097:blood; D004311:Double-Blind Method; D004435:Eating / Q000502:physiology*; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D005419:Flavonoids / Q000032:analysis; D044948:Flavonols / Q000097:blood; D006801:Humans; D008297:Male; D019697:Onions / Q000737:chemistry*; D010865:Pilot Projects; D015539:Platelet Activation / Q000502:physiology*; D010974:Platelet Aggregation / Q000502:physiology*; D011794:Quercetin / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood; D015398:Signal Transduction / Q000502:physiology
chemical_list: D004187:Disaccharides; D005343:Fibrinolytic Agents; D005419:Flavonoids; D044948:Flavonols; C047368:3-methylquercetin; C508967:tamarixetin; D003094:Collagen; D011794:Quercetin