Effects of Riboflavin-2', 3', 4', 5'-tetrabutyrate on Platelet Function and Plasma Lipids

Abstract

Riboflavin-2', 3', 4', 5'-tetrabutyrate (B₂-But) inhibited, in vitro, ADP (4 μg/ml)-induced platelet aggregation whenadded at the concentration of more than 1 jug/ml and arachidonic acid (Aa) (1 mM)- induced platelet aggregation when given at the concentration of more than 0.1 jug/ml. These inhibitions were dose-dependent. Both cyclic AMPand prostaglandin metabolites in the platelets, however, remained unchanged when the amount of B₂-But added was between 0.1-10 μg/ml. In a volunteer study, 80 mg of B₂-But taken in one bolus inhibited both ADP-and Aa-induced platelet aggregation 4 hr after oral administration. The administration of B₂-Butat this dose was associated with a significant decrease in malondialdehyde formation in plasma. The oral administration of 40 mg (t.i.d.) of B²-But daily did not result in significant changes in ADP-and Aa-induced platelet aggregation. B₂ -But showed no significant effects on either platelet adhesiveness or collagen-induced platelet aggregation, in vitro or in vivo. Our data suggest that a decrease of lipoperoxide in plasma, not in platelets, influences platelet aggregation induced by ADP and Aa.