Effects of garlic extract on platelet aggregation: a randomized placebo-controlled double-blind study.
1. Studies of the effects of garlic on platelet aggregation have produced inconsistent results possibly related to variations in study design and in the garlic preparations used. 2. The present study examined the effects on platelet aggregation and serum thromboxane and lyso-platelet activating factor, of feeding garlic extract to healthy men using a placebo-controlled, double-blind design. The effects of the same garlic preparation on platelet aggregation in vitro were also investigated. 3. There were no significant differences in platelet aggregation with adenosine diphosphate, platelet activating factor (PAF) or collagen according to treatment group. Serum thromboxane and lysoPAF also showed no change related to garlic supplements. 4. In vitro aggregation with collagen decreased linearly with increasing amounts of garlic extract, but concentrations were higher than those attainable in vivo. Gastrointestinal side effects prevented the use of higher doses of garlic which must be considered to be pharmacological as they exceed changes achievable by dietary modification.
Morris
J
J
University Department of Medicine, Royal Perth Hospital, Western Australia.
Burke
V
V
Mori
T A
TA
Vandongen
R
R
Beilin
L J
LJ
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D003094:Collagen / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005500:Follow-Up Studies; D005737:Garlic; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D010946:Plants, Medicinal; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000032:analysis; D010974:Platelet Aggregation / Q000187:drug effects*; D012044:Regression Analysis; D013931:Thromboxanes / Q000097:blood
C029271:O-deacetyl platelet activating factor; D010936:Plant Extracts; D010972:Platelet Activating Factor; D013931:Thromboxanes; D000244:Adenosine Diphosphate; D003094:Collagen