Salvianolic Acid B inhibits platelet adhesion under conditions of flow by a mechanism involving the collagen receptor α2β1

Salvianolic acid B (SAB) is a component of Danshen, a herb widely used in Chinese medicine, and was previously shown to exert a number of biological activities including inhibition of platelet function, but the exact mechanisms involved are unclear. SAB dose-dependently inhibited platelet deposition from flowing, anticoagulated whole blood to immobilized collagen at both venous and arterial shear rate, whereas platelet deposition to immobilized fibrinogen was not affected. The inhibitory effect of SAB on platelet adhesion to collagen was independent of alpha llb beta 3, since SAB still inhibited platelet deposition in the presence of a alpha ll beta f 3-blocking peptide. SAB inhibited static platelet adhesion to a synthetic peptide specific for the collagen receptor alpha 2 beta 1, whereas platelet adhesion to a glycoprotein VI-specific peptide was not affected. SAB inhibited binding of an antibody against alpha 2 beta 1 to platelets as studied by f tow cytometry, and inhibited the interaction of soluble alpha 2 beta 1 to immobilized collagen in a solid phase binding assay. These combined results indicate that SAB inhibits platelet adhesion to immobilized collagen by interfering with the collagen receptor alpha 2 beta 1. (c) 2008 Elsevier Ltd. All rights reserved.