<i>In vitro</i> Effect of Avarone and Avarol, a Quinone/Hydroquinone Couple of Marine Origin, on Platelet Aggregation

Abstract

We investigated the effect on human platelet aggregation of the naturally occurring quinone/hydroquinone couple, avarone and avarol. Avarone exerted antiplatelet activity both on platelet-rich plasma and, to a greater extent, on washed platelets. The quinone inhibited the platelet aggregatory process with all the agonists used. The highest inhibitory potency occurred with arachidonic acid or A23187 as stimulating agents. In the case of agonists such as adenosine 5' diphosphate, platelet-activating factor or U46619, the antiaggregatory effect was more pronounced on the second wave. Inhibition of the aggregatory process paralleled thromboxane B2 formation. Avarol also exerted antiplatelet activity, even though its inhibitory potency was much lower than that of avarone.