Quillaja saponins are a potent contractor of uterine smooth muscle tissue in vitro

Caulophyllum thalictroides, commonly known as blue cohosh, is a plant indigenous to the northeastern region of North America. The roots and rhizomes have been used in herbal medicine for centuries as they are thought to stimulate uterine contractions during labor; they have been shown to contract mouse uterine tissues in vitro. The active constituents thought to be responsible for these actions are the alkaloids and saponins. The primary purpose of this research was to expose isolated mouse uterine tissues to Quillaja saponaria, which contains saponins similar to those isolated from blue cohosh, and observe any contractile responses. Tissues collected from mice were suspended individually in organ baths and saponin solutions (0.1-20%) were added. Contractile responses were analyzed as a percent of the tissues contractile response to 10-5 M oxytocin. Saponins were found to increase force (P<0.0001) as well as frequency (P<0.0001) of contractions when compared to 0% treatment (the tissues endogenous spontaneous motility). The saponin responses, however were not statistically different from each other. Saponins are considered to be permeating substances that create pores in the plasma membrane, allowing for the influx of extracellular Ca2+ ions and initiating the smooth muscle contractile cascade. Since Quillaja saponins do contract uterine smooth muscle, it is likely that the saponins found in the roots and rhizomes of blue cohosh would also contribute to the overall contractile response as seen from extracts of the parent plant.