Effects of baicalein isolated from roots of Scutellaria baicalensis Georgi on interleukin 1 beta- and tumour necrosis factor alpha-induced tissue-type plasminogen activator and plasminogen activator inhibitor-1 production in cultured human umbilical vein endothelial cells

The effects were examined of baicalein on tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) production stimulated by interleukin-1 alpha (IL-1 beta) and tumour necrosis factor-alpha (TNP-alpha) in cultured human vein umbilical endothelial cells (HUVECs), IL-1 beta and TNF-alpha increased PAI-1 production, but they decreased t-PA production, Baicalein isolated from the roots of Scutellaria baicalensis Georgi, inhibited the PAI-1 production stimulated by IL-1 beta and TNF-alpha, but it had no effect on the t-PA, In addition, protein kinase C (PKC) inhibitors such as H7 and sphingosine decreased the reduction of t-PA and the increase of PAI-1 by IL-1 beta and TNF-alpha. On the other hand, dibutryl cAMP and forskolin had no effect on the t-PA reduction and PAI-1 increase by IL-1 beta and TNF-alpha. Moreover, IL-1 beta and TNF-alpha did not cause [Ca2+] elevation. These results suggest that the inhibitory action of baicalein on the PAI-1 production by both cytokines might be directly mediated through PKC inhibition. (C) 1997 by John Wiley & Sons, Ltd.