Relaxant effect of 6-deoxyclitoriacetal on smooth muscle preparations.

The pharmacological effect of 6-deoxyclitoriacetal (6-DA), a rotenoid compound isolated from the roots of Clitoria macrophylla Wall. (Papilionaceae), was examined on different smooth muscle preparations. 6-Deoxyclitoriacetal 0.2 mg/ml produced a significant decrease in the spontaneous contraction of isolated rat uterus. It also suppressed the contraction induced by acetylcholine 5x10(-6) M and oxytocin 5x10(-3) IU/ml. The cumulative contractile responses of rat aortic strips caused by serotonin 10(-8)-10(-4) M and norepinephrine 10(-11)-10(-7) M were reduced by 6-DA 0.4 mg/ml. In calcium free Kreb's solution, 6-DA inhibited the aortic contraction produced by a cumulative dose of calcium chloride (0.1-30 mM). In guinea-pig ileum, 6-DA 0.15 mg/ml exerted the spasmolytic activity by inhibition of the contractile response evoked by various contractile agents e.g. acetylcholine 10(-9)-10(-5) M, serotonin 10(-9)-10(-5) M and histamine 10(-9)-10(-5) M. All of the results indicated that 6-DA could induce a smooth muscle relaxant effect by interference with intracellular calcium metabolism.