Strong antiproliferative effects of baicalein in cultured rat hepatic stellate cells

Recently, antifibrogenetic effects of Sho-saiko-to, a traditional herbal medicine in Japan, have been shown in experimental hepatic fibrosis, and flavonoids in Sho-saiko-to are suspected as active ingredients. Thus, we evaluated the effects of baicalein, a major flavonoid in Sho-saiko-to, on proliferation and protein synthesis in cultured rat hepatic stellate cells. Baicalein decreased [H-3]thymidine incorporation in cells stimulated with platelet-derived growth factor-B subunit homodimer (PDGF-BB) in a concentration-dependent manner (approximate ED50 < 10 mu M, P < 0.0001), and the decrease observed with 10 mu M baicalein was greater than those observed with 5 mu M retinol or 500 mu M 3-isobutyl-1-methylxanthine (IBMX). Baicalein consistently decreased [H-3]thymidine incorporation and cell number in cells stimulated with fetal calf serum (ED50 < 10 mu M, P < 0.0001), and moderately suppressed [H-3]leucine and [H-3]proline incorporation (P < 0.0001). These results demonstrate the strong antiproliferative effect of baicalein in hepatic stellate cells, showing the possibility of baicalein as an antifibrogenetic drug for hepatic fibrosis. (C) 1999 Elsevier Science B.V. All rights reserved.