Saururus chinensis has been widely used as a
traditional medicine for the treatment of
beriberi,
hypertension,
pneumonia,
edema,
jaundice and
gonorrhea. However, there is only limited information on the cardiovascular effects of S. chinensis extract or its single compounds. The present study was performed to investigate the effects of active
lignans isolated from the extract of S. chinensis on vascular responses and heart functions. The
vasorelaxant activity-guided fractionation of roots extract of S. chinensis led to the isolation of eight
lignans as active principles. These
lignans produced concentration-dependent relaxations of the endothelium-intact aortic preparations of rat aorta. Particularly, saucerneol ( 1),
saucerneol D ( 2) and
machilin D ( 8) exhibited distinctive
vasorelaxant activity (EC (50) values: 2.2, 12.7 and 17.8 microM, respectively), which were significantly inhibited by removal of functional endothelium or pretreatment with
N(G)-nitro-L-arginine methyl ester. Saucerneol ( 1) and
saucerneol D ( 2) caused a significant decrease in left ventricular pressure, +dP/dt (max) and heart rate in isolated hearts. These results suggest that several
lignans including saucerneol ( 1),
saucerneol D ( 2) and
machilin D ( 8), isolated from the
ethanol extract of the roots of S. chinensis, have significant cardiovascular effects such as
vasorelaxant and negative inotropic actions.