title: Cocoa inhibits platelet activation and function.
abstract: BACKGROUND
  Epidemiologic studies have shown inverse associations between dietary polyphenols and mortality from coronary heart disease. However, the basis for this protective association is uncertain. Food polyphenols reportedly have antioxidant properties and decrease platelet function in vitro.
  
  
  OBJECTIVE
  This study sought to evaluate whether consumption of a polyphenol-rich cocoa beverage modulates human platelet activation and primary hemostasis.
  
  
  METHODS
  Peripheral blood was obtained from 30 healthy subjects before and 2 and 6 h after ingestion of a cocoa beverage (n = 10), a caffeine-containing control beverage (n = 10), or water (n = 10). Platelet activation was measured in terms of expression of activation-dependent platelet antigens and platelet microparticle formation by using fluorescent-labeled monoclonal antibodies and flow cytometry. Primary platelet-related hemostasis was measured with a platelet function analyzer.
  
  
  RESULTS
  Ex vivo epinephrine- or ADP-stimulated expression of the fibrinogen-binding conformation of glycoprotein IIb-IIIa was lower 2 and 6 h after consumption of cocoa than before consumption. Cocoa consumption also decreased ADP-stimulated P-selectin expression. In contrast, epinephrine-induced platelet glycoprotein IIb-IIIa expression increased after consumption of the caffeine-containing beverage but not after water consumption. Platelet microparticle formation decreased 2 and 6 h after cocoa consumption but increased after caffeine and water consumption. Primary hemostasis in response to epinephrine in vitro was inhibited 6 h after cocoa consumption. The caffeine-containing beverage inhibited ADP-induced primary hemostasis 2 and 6 h after consumption.
  
  
  CONCLUSIONS
  Cocoa consumption suppressed ADP- or epinephrine-stimulated platelet activation and platelet microparticle formation. Cocoa consumption had an aspirin-like effect on primary hemostasis.
authors.affiliation: Department of Nutrition, the University of California, Davis, CA 95616, USA.
authors.forename: D
authors.initials: D
authors.lastname: Rein
authors.forename: T G
authors.initials: TG
authors.lastname: Paglieroni
authors.forename: T
authors.initials: T
authors.lastname: Wun
authors.forename: D A
authors.initials: DA
authors.lastname: Pearson
authors.forename: H H
authors.initials: HH
authors.lastname: Schmitz
authors.forename: R
authors.initials: R
authors.lastname: Gosselin
authors.forename: C L
authors.initials: CL
authors.lastname: Keen
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000975:Antioxidants / Q000494:pharmacology; D001628:Beverages; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002099:Cacao; D003327:Coronary Disease / Q000517:prevention & control; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005419:Flavonoids; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010636:Phenols / Q000494:pharmacology; D015539:Platelet Activation / Q000187:drug effects / Q000502:physiology*; D011108:Polymers / Q000494:pharmacology; D059808:Polyphenols; D012016:Reference Values
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D000244:Adenosine Diphosphate; D004837:Epinephrine