Demethylbellidifolin inhibits adhesion of monocytes to endothelial cells via reduction of tumor necrosis factor alpha and endogenous nitric oxide synthase inhibitor level

The effect of demethylbellidifolin (DMB), a major compound of Swertia davidi Franch, on the adhesion of monocytes to endothelial cells induced by oxidized low-density lipoprotein (ox-LDL) was studied. Adhesion of monocytes to endothelial cells was induced by treatment with ox-LDL (100 microg/mL) for 48 h. Levels of tumor necrosis factor-alpha (TNF-alpha) and asymmetric dimethylarginine (ADMA, an endogenous inhibitor of NOS) in conditioned medium and the activity of dimethylarginine dimethylaminohydrolase (DDAH) in endothelial cells were measured. DMB (3 or 10 micromol/L) significantly inhibited the adhesion of monocytes to endothelial cells, attenuated an increase in levels of TNF-alpha and ADMA, and a decrease in the activity of DDAH by ox-LDL. The present results suggest that DMB inhibits the increased adhesion of monocytes to endothelial cells induced by ox-LDL, and that the effect of DMB is related to reduction of the ADMA concentration via reduction of TNF-alpha production in cultured endothelial cells treated with ox-LDL.