Chinese patent medicine shouhui tongbian capsule attenuated loperamide-induced constipation through modulating the gut microbiota in rat

Shouhui tongbian capsule (SHTC) is a commercial Chinese patent medicine used in the treatment of constipation. However, its mechanism of action remains unclear.The present study was undertaken to assess SHTC relieved effects on the clinical symptoms of loperamide (LOP) induced constipation in Sprague Dawley (SD) rat model and to clarify the relationship between the protective effect of SHTC on constipation and the gut microbiota.Constipation male SD rats models were induced with solution of LOP (1.5 mg/kg bw), and rats were treated with an oral dose of SHTC (35, 70 mg/kg bw) three times a day after successful modeling. All rats were assessed weekly by change in body weight, gastric emptying rate, fecal moisture content and wet/dry weight. Hematoxylin and eosin (H&E) were used to observe parts of the rats small intestine. The gut microbiota in colonic contents was analyzed using 16SrRNA gene sequencing. Contents of short-chain fatty acids (SCFAs) were analyzed by gas chromatography-mass spectrometer (GCMS).The results confirmed the therapeutic effects of SHTC on constipation. Specifically, SHTC could alleviate the decrease in body weight, gastric emptying rate and fecal moisture content caused by LOP-induced constipation. The pathological damage of small intestine was significantly improved by H&E staining. Notably, SHTC increased the relative abundances of Lactobacillus and the ratio of Firmicutes to Bacteroides (F/B). In addition, the content of acetic acid and propionic acid was significantly increased in constipated rats fed with SHTC.SHTC could ameliorate the development of LOP-induced constipation in rats by remodeling the structure of gut microbial community and regulating production of intestinal metabolites.