Effect of water extract from Berberis heteropoda Schrenk roots on diarrhea-predominant irritable bowel syndrome by adjusting intestinal flora

The aim of the present study was to investigate the antidiarrheal effect of Berberis heteropoda Schrenk roots (BHS), which are used by Chinese minorities to treat diarrhea, through regulation of intestinal flora and related signaling pathways.Wistar rats were randomly divided into 6 groups: Control group (Con), Model group (Mod), three BHS groups (BHS-L (0.65 g/kg), BHS-M (1.955 g/kg), BHS-H (5.86 g/kg) and Bifidobacterium group (Bif). The model of diarrhea-based irritable bowel syndrome (D-IBS) was induced by intragastric administration combined with restraint stress. The CRD method was used to determine the AWR score and the Bristol fecal score. Quantification of the intestinal bacteria groups in feces was performed using colony counting on plates. The mRNA expression levels of Gpr41, Gpr43, TLR2, TLR4, and nuclear protein κB were determined by qRT-PCR, and the relative abundances of intestinal flora in the intestinal contents were determined by high-throughput gene sequencing ratios.Oral administration of BHS (L, M and H) significantly reduced the AWR score and the Bristol fecal score, significantly relieved diarrhea in D-IBS rats, reduced the number of Enterococci and Enterobacteria in feces, increased the number of Bifidobacteria and Lactobacilli, and upregulated the expression of SCFA in plasma. qRT-PCR analysis showed that the expression of TLR2, TLR4, Gpr41, Gpr43 and NF-κB in the BHS groups was downregulated. D-IBS rats reduced the abundance and diversity of intestinal flora and BHS (L, M and H) regulated the abundance and diversity of their intestinal flora.The above data suggest that BHS potentially alleviates diarrhea, intestinal flora disorder and intestinal inflammation in D-IBS rats by regulating the immunological pathways. BHS is a promising agent in the treatment of D-IBS.