The Ca2+ antagonist activity of lignans.

Abstract
A number of lignans, including those isolated from Arctium lappa (Compositae), were subjected to Ca2+ antagonist assay. The most potent activity occurred in trachelogenin, the calculated Ic50 and pA2 of which were 1.1 .times. 10-6 M and 6.60 respectively. Trachelogenin had a potent and long-lasting antihypertensive effect on spontaneously hypertensive rats.