Effect of Aqueous Extract of <i>Glycyrrhiza glabra</i> on rabbit ileum motility in comparison with Acetylcholine, Atropine and Ondansetron

Objectives: Gastrointestinal disorders such as irritable bowel syndrome can affect the quality of life and increase the risk of psychological problems such as depression. Drugs such as hyoscyamine and metoclopramide and 5-HT3 receptor antagonists such as Alosteron are used nowadays for symptomatic management, but their use is associated with adverse effects leading to decreased patient compliance. Nowadays, natural plant-based medicine is preferred by people due to its fewer adverse effects; therefore, the current study was planned to evaluate the effect of Glycyrrhiza glabra on the intestinal smooth muscle of rabbits. Our study aims to define the mechanism of action of G. glabra in promoting or inhibiting gut motility. Materials and Methods: An experimental in vitro study was conducted in the Pharmacology Department of Services Institute of Medical Sciences Lahore in January 2023. Rabbit ileal tissue was used. PowerLab (ADInstruments) was used to record the contractions of ileal smooth muscles. After mounting, the tissue was given to rest for 30 min, after which baseline contractions were recorded. Then, 0.8 mL of acetylcholine (10 −5 ) was added, and contractions were recorded for 30 s. Freshly prepared Tyrode’s solution was used to rinse the tissue three and then given rest for 3 min. Then, ileal tissue was treated with G. glabra 5%, 15% and 20% and their effect was recorded. Acetylcholine served as a positive control, and the action of G. glabra 5%, 15% and 20% solution was compared with it. After that, G. glabra was used in the presence of drugs that inhibit intestinal motility, atropine and ondansetron 0.0036 µM and 0.036 µM, respectively. Results: Results showed that G. glabra 5%, 15% and 20% increased intestinal motility significantly ( P &lt; 0.0001) in comparison with acetylcholine. However, when G. glabra was used in the presence of antagonists, atropine and ondansetron, then, it reduced intestinal motility significantly ( P &lt; 0.0001). Conclusion: Aqueous extract of G. glabra has a dual effect on gut motility that is a direct muscarinic receptor agonist and indirect modulator of enteric vagus nerve terminal through serotonin 5-HT3 receptors.