Genistein inhibits reactive oxygen species (ROS) production, shape change, and aggregation in rat platelets

• Published in: Nutrition research (New York, N.Y.) Vol. 20; no. 1; pp. 47 - 57
• Main Authors: Schoene, Norberta W., Guidry, Catherine A.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 2000; Elsevier Science
• Subjects: 7′-Dichlorofluorescein; Biological and medical sciences; Blood coagulation. Blood cells; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Genistein; Molecular and cellular biology; Platelet; Platelet Volume; Platelets; Reactive Oxygen Species; 7′-Dichlorofluorescein; 2; Flow Cytometry; Reactive Oxygen Species; Genistein; Platelet Volume; Platelets; Oxygen; Rat; Rodentia; Biosynthesis; Antioxidant; Flavonoid; Free radical; Aggregation; Vertebrata; Mammalia; Animal; Platelet function; Inhibition
• ISSN: 0271-5317; 1879-0739
• DOI: 10.1016/S0271-5317(99)00137-2

Reactive oxygen species (ROS) are generated in platelets by activation of a multicomponent NADPH oxidase. ROS, by inhibiting tyrosine phosphatase(s), shift the balance of protein tyrosine phosphorylation-dephosphorylation reactions. The resulting increased tyrosine phosphorylation of proteins escalates signaling events that promote platelet activation. Flow cytometry in combination with 2′,7′-dichlorofluorescein permitted detection of ROS production during collagen stimulation of platelets in whole blood. The assay was used to determine the effects of genistein, a tyrosine kinase inhibitor, on receptor-mediated production of ROS in platelets from rats. Pretreatment of blood samples with varying concentrations of genistein resulted in an inhibition of the collagen-induced increase in fluorescence (10 μM/40%; 35 μM/65%; 70 μM/65%; genistein concentration/% inhibition, respectively). This inhibition of ROS production paralleled inhibition of shape change and the disappearance of single platelets following addition of collagen to whole blood. Addition of genistein reduced shape change by 51% and the loss of single platelets by 57% (74% aggregation, collagen alone; 27% aggregation, 140 μM genistein plus collagen; n=8). The ability of genistein to decrease receptor-mediated ROS production while inhibiting platelet aggregation supports the importance of ROS signaling in platelet function. This action of genistein may be explained by tyrosine kinase inhibition, direct antioxidant action to reduce ROS, or protection of tyrosine phosphatase(s). Further experiments are required to determine which mechanism(s) produces the decrease in platelet aggregatory responses.