Abstract

The diterpenoid diacetyl epitaondiol, isolated from Stypopodium flabelliforme was studied in cardiovascular system. In vitro, a negative inotropic effect of 35% was shown in isolated atrium. A negative chronotropic effect was also detected and both were reversible by washing with physiological solution. In aortic rings with endothelium, the phenylephrine curve dosis-effect was moved to the right. In the contraction produced by potassium, an opposite effect was observed: in the intracellular calcium dependence (phase 1), diacetyl epitaondiol is a calcium antagonist, in the phase 2 there is a slight increase of calcium intake.