VASOACTIVE EFFECTS OF CIMICIFUGIC-ACID-C AND CIMICIFUGIC-ACID-D, AND FUKINOLIC ACID IN CIMICIFUGA RHIZOME

Vasoactive effects of cimicifugic acids A-E, fukinolic acid and fukiic acid isolated from Cimicifuga plants were investigated using rat aort ic strips. Cimicifugic acid D and fukinolic acid at 3 x 10(-4) m cause d a sustained, slowly developing relaxation of aortic strips precontra cted with norepinephrine (NE) in preparations with or without endothel ium. Cimicifugic acid C inversely caused a weak contraction. Cimicifug ic acids A, B and E and fukiic acid showed no vasoactivity at 3 x 10(- 4) M. Cimicifugic acids A-E and fukinolic acid are esters between cinn amic acids and the hydroxyl group of benzyltartaric acids. For the man ifestation of vasoactivity in the rat aorta, it is concluded that in t he cinnamic acid moiety, a caffeoyl group might be necessary for the r elaxation activity, and the p-coumaroyl group causes contraction. Conc entration response curves for the Ca2+-induced contracture of depolari zed aortic strips with isotonic high K+ were not affected by cimicifug ic acid D or fukinolic acid. The Ca2+-induced contraction of aortic st rips, preincubated with 10(-6) M NE in the presence of 10(-6) nr nicar dipine and 0.01 mM EGTA in Ca2+-free solution, were inhibited by cimic ifugic acid D and fukinolic acid. These results indicated that the inh ibition by cimicifugic acid D and fukinolic acid of the NE-induced con traction of rat aorta are attributable to the suppression of Ca2+ infl ux from the extracellular space enhanced by NE.