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

Context: 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. Objective: 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. Materials and methods: 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 mu g/mL), carbachol (CCh, 5 mu g/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. Results: 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 mu g/mL; 14.65-48.32%), CCh (5 mu g/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. Discussion and conclusion: 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.