Effects of four medicinal herbs on human vascular endothelial cells in culture

Background Danshen (DS, Salvia miltiorrhiza), Shanchi (SQ, Panax notoginseng), Shanzai (SZ, Hawthorn) and Heshouwu (HSW, Polygonum multiflorum Thunb) are four medicinal herbs commonly used in traditional Chinese medicine and previously shown to have activity that may contribute to cardiovascular protection. This study aims to investigate effects of these herbs on vascular endothelial cells with respect to cell viability and expression of cellular adhesion molecules under inflammatory conditions. Methods Herbal extracts were prepared by an established industrial manufacturing process. Human umbilical vein endothelial cells (HUVEC) were incubated with the herbal extract under normal or serum-free culture and tumor necrosis factor (TNF) α stimulation. Cell apoptosis, apoptosis-associated gene expression, expression of cellular adhesion molecules, DNA synthesis, and growth were assessed via morphological examination, Annexin-V staining, Western blotting analysis, Flow-Cytometry, [3H]-thymidine incorporation assay, and cell number study. Results SZ and HSW significantly inhibited apoptosis in HUVEC undergoing serum deprivation and TNFα stimulation, accompanied by down-regulation of caspase-3 gene expression. DS and SQ significantly attenuated TNFα-induced expression of adhesion molecule VCAM-1 and also ICAM-1 by DS in the cells. All four herbs at therapeutic concentrations (100 μg/mL) inhibited DNA synthesis (10–42% decrease in [3H]-thymidine incorporation rates) and growth (5–10% decrease in cell numbers) in HUVEC under normal cultures. Conclusion DS, SQ, SZ and HSW are physiologically active on human vascular endothelial cells. The actions by HSW and SZ to reduce apoptosis and DS and SQ to inhibit adhesion molecule expression may help protect endothelial function and inhibit atherogenesis, while their actions to inhibit DNA synthesis and cell growth may weaken the ability of endothelial repair. Further studies are needed to identify the chemical compounds responsible to these physiological effects by these herbs.