Effect of platycodin D on gastric motility, gastric emptying and gastrointestinal transit

Diarrhea is a condition which causes malabsorption and dehydration. Recently, the anti-motility effect of several herbal compounds for the treatment of hypermotility-induced diarrhea has been studied. The root of Platycodon grandiflorum has been widely used in oriental medicine for the treatment of various chronic inflammatory diseases. The aim of the present study was to assess the effects of Platycodin D (PD), the major triterpene saponin in the root of P. grandiflorum, on gastrointestinal (GI) motility by assessing both gastric emptying (GE) and intestinal transit (IT) in mice with different treatment protocols. Mice were randomly allocated to 5 groups (n = 15/group) according to their treatment protocols (control, administered with antikinetics: atropine, dopamine, or with pro-kinetics: itoride, bethanechol) for each GE and IT test. Each group was subsequently divided into 3 subgroups (n = 5) pre-treated with different PD doses (0, 2.5, and 5 mg/kg). Pre-treatment with PD in the control treatment group of mice showed reduced GE and IT in a dose-dependent manner. At the maximum PD effect, GE and IT were reduced by 63% and 50%, respectively, compared with those in the normal control group. In the groups given atropine or dopamine, pre-treatment with PD further reduced GE and IT by 35% to 58%, respectively. The PD pre-treatment dramatically reduced the GI motility enhanced by itopride and bethanechol. On the whole, these results suggest that PD treatment might be beneficial in motility-induced diarrhea.