Salviae Miltiorrhizae (SM), a clinically common used herb, can activate blood circulation and resolve stasis. We have investigated the effects of salvianolic acid B (Sal B), a pure compound extracted from the dried SM roots, on fibrinolytic (tissue-type plasminogen activator and plasminogen activator inhibitor, t-PA and PAI) and anticoagulant (thrombomodulin,TM) properties of cultured human umbilical vein endothelial cells (HUVECs). When HUVECs were treated with Sal B, a dose (0.0125-0.5 mg/ml) and a time-dependent decrease in PAI activity were observed. PAI type 1 (PAI-1) antigen and PAI-1 mRNA expression significantly decreased compared to control values in the conditioned media of HUVECs pretreated with Sal B for 12 h. Moreover, TM activity reached a maximum stimulation of 1.25 fold over control levels in the pretreatment of Sal B for 12 h and t-PA and TM specific mRNA expression also increased (1.7 and 1.8 fold, respectively). In conclusion that Sal B increased the fibrinolytic and anticoagulant potential of cultured HUVECs by up-regulating the expression of t-PA and TM, and by down-regulating the expression of PAI-1. These data suggest that Sal B is clinically effective because of its ability to change the gene expression profile of endothelial cells thereby preventing vascular events.
