Coumarins with Different Substituents from Have Opposite Effects on Uterine Smooth Muscle.

Houtt is an exceptional medicinal herb used to treat obstetrical and gynecological diseases in traditional Chinese medicine, and it has significant effects on the treatment of dysmenorrhea and postpartum hemorrhage. This study investigated the effects of coumarins with diverse substituent groups from on isolated uterine smooth muscle and the preliminary mechanism of the most effective compound. Eight coumarins isolated from were assessed for their effects on the isolated uterine smooth muscle of nonpregnant rats in vitro. Coumarins and significantly promoted the contraction of rat uterine smooth muscle strips, whereas coumarins - showed remarkable relaxing effects against oxytocin (OT)-induced rat uterine smooth muscle contraction. Further mechanism investigations revealed that bergapten (coumarin ) significantly increased the level of Ca in uterine tissues by promoting extracellular Ca influx and intracellular Ca release, which were related to the activation of L-type Ca channels and α-receptors. By contrast, osthole (coumarin ), an α receptor antagonist, inhibited OT-induced uterine smooth muscle contraction by decreasing the level of Ca in uterine tissues via inhibition of extracellular Ca influx and intracellular Ca release. This study demonstrates that the coumarins from are effective substances for regulating uterine smooth muscle contraction, but different coumarins with diverse substituent groups have different, even opposite effects. It can be inferred that coumarins are closely related to the efficacy of in the treatment of dysmenorrhea and postpartum hemorrhage.