ABSTRACT
Aim To investigate the impact and mechanism of Weichang'an Pill(WCA),its ethanol extract(EE),water extract(WE),and active ingredients on the contraction of isolated rat ileum smooth muscles induced by acetylcholine(ACh). Methods In vitro tissue bath experiment,WCA,EE,WE,or their active ingredients were added under the action of ACh,and then the contraction tension of isolated ileum smooth muscle from rats was recorded. The binding affinity ofthe active ingredients to the muscarinic acetylcholine M3 receptor was explored by molecular docking. Results WCA,EE,and WE were able to considerably inhibit the excitatory contraction of the ileal smooth muscles induced by ACh. Costunolide,dehydrocostus lactone,santalol,muscone,emodin,chrysophanol,physcion,crotonoside,magnolol,and honokiol were also significantly effective against ACh-induced ileal smooth muscle contraction. Conclusions WCA,EE,WE,and their active ingredients may help to promote intestinal smooth muscle relaxation by blocking the binding of the M3 receptor on the membrane of ileal smooth muscle with ACh.