Relaxative effect of core licorice aqueous extract on mouse isolated uterine horns

Primary dysmenorrhea is one of the most frequent gynecological disorders in young women. Chinese herbal medicine has the advantage in terms of multi-targeting efficacy, lower toxicity, as well as lower cost. Core licorice is the hard and atropurpureus heart part in root and rootstock of Glycyrrhiza uralensis Fisch (Leguminosae), having a therapeutic effect on dysmenorrhea.This experiment indicated the spasmolytic effect of core licorice aqueous extract (CLE) on spontaneous rhythmic contractions and spasmogen-provoked contractions of stilbestrol primed, estrogen-dominated, non-pregnant mouse isolated uterine horns and its spasmolytic mechanism.We investigated the spasmolytic effect of CLE (0.025-0.1 mg/mL) on spontaneous contractions and potassium chloride (KCl, 40 mM), acetylcholine (ACh, 5 μg/mL), carbachol (CCh, 5 μg/mL), oxytocin (OT, 2 U/L) or bradykinin (5 ng/mL)-provoked contractions of mouse isolated uterine horns. Contractions were recorded by tension force transducers using Biolap 420F software on a PC.Our present study showed that graded, escalated concentrations of CLE (0.025-0.1 mg/mL) significantly inhibited the amplitude of spontaneous phasic contractions (15.03-55.10%), as well as the contractions produced by KCl (40 mM; 20.16-53.99%), ACh (5 μg/mL; 14.65-48.32%), CCh (5 μg/mL; 38.40-76.70%), OT (2 U/L; 21.53-58.49%) or bradykinin (5 ng/mL; 58.01-79.44%) of the estrogen-dominated isolated mice uterine horn preparations in a concentration-related manner.The spasmolytic effect of CLE observed in the present study lends pharmacological support to the traditional use of core licorice in the management, control and treatment of primary dysmenorrhea.