title: Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function.
abstract: BACKGROUND
  Flavonoids may be partly responsible for some health benefits, including antiinflammatory action and a decreased tendency for the blood to clot. An acute dose of flavanols and oligomeric procyanidins from cocoa powder inhibits platelet activation and function over 6 h in humans.
  
  
  OBJECTIVE
  This study sought to evaluate whether 28 d of supplementation with cocoa flavanols and related procyanidin oligomers would modulate human platelet reactivity and primary hemostasis and reduce oxidative markers in vivo.
  
  
  METHODS
  Thirty-two healthy subjects were assigned to consume active (234 mg cocoa flavanols and procyanidins/d) or placebo (< or = 6 mg cocoa flavanols and procyanidins/d) tablets in a blinded parallel-designed study. Platelet function was determined by measuring platelet aggregation, ATP release, and expression of activation-dependent platelet antigens by using flow cytometry. Plasma was analyzed for oxidation markers and antioxidant status.
  
  
  RESULTS
  Plasma concentrations of epicatechin and catechin in the active group increased by 81% and 28%, respectively, during the intervention period. The active group had significantly lower P selectin expression and significantly lower ADP-induced aggregation and collagen-induced aggregation than did the placebo group. Plasma ascorbic acid concentrations were significantly higher in the active than in the placebo group (P < 0.05), whereas plasma oxidation markers and antioxidant status did not change in either group.
  
  
  CONCLUSIONS
  Cocoa flavanol and procyanidin supplementation for 28 d significantly increased plasma epicatechin and catechin concentrations and significantly decreased platelet function. These data support the results of acute studies that used higher doses of cocoa flavanols and procyanidins.
authors.affiliation: Department of Food Science, RMIT University, Melbourne, Australia. karen.murphy@adelaide.edu.au
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Murphy
authors.forename: Andriana K
authors.initials: AK
authors.lastname: Chronopoulos
authors.forename: Indu
authors.initials: I
authors.lastname: Singh
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Francis
authors.forename: Helen
authors.initials: H
authors.lastname: Moriarty
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Pike
authors.forename: Alan H
authors.initials: AH
authors.lastname: Turner
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Mann
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sinclair
mesh_terms: D000328:Adult; D044946:Biflavonoids; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D002099:Cacao / Q000737:chemistry*; D002392:Catechin / Q000008:administration & dosage* / Q000097:blood; D004032:Diet; D005260:Female; D005419:Flavonoids / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D044945:Proanthocyanidins; D013997:Time Factors
chemical_list: D044946:Biflavonoids; D005419:Flavonoids; D010975:Platelet Aggregation Inhibitors; D044945:Proanthocyanidins; C017674:procyanidin; D002392:Catechin