Study on the mechanism of Yihuang powder ethanol extract on spleen deficiency diarrhea in young rats based on intestinal flora and metabonomics.

Infantile spleen deficiency diarrhea (SDD) impacts children's health. Yihuang Powder (YHP) is a traditional prescription for treating it, and the ethanol extract of YHP (EYHP) has been optimized by the research group, yet its differences from the traditional water extract of YHP (WYHP) remain unclear. This study aimed to clarify the variances in chemical composition and pharmacological effects between EYHP and WYHP, and reveal EYHP's mechanism in treating SDD via intestinal flora and fecal metabolomics. Ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) was used for chemical composition analysis. A composite modeling method was employed to establish the SDD model in young rats. Multiple measurements were carried out, including recording body weights and diarrhea, measuring serum gastrointestinal hormones, observing colon tissue pathology by Hematoxylin-eosin (HE) staining, determining the mRNA expression level of inflammatory factors in colon tissue, analyzing the effect on intestinal flora by 16S rRNA sequencing, and analyzing fecal metabolites by UPLC-Q-TOF/MS. The results showed that 94 components were identified in EYHP and 59 in WYHP. EYHP had stronger pharmacological effects in improving SDD symptoms in young rats. It regulated intestinal flora by increasing the abundance of probiotics and decreasing that of pernicious bacteria, and 24 potential fecal metabolite biomarkers were screened. In conclusion, EYHP can improve SDD in young rats by regulating intestinal flora and fecal metabolites, offering a valuable approach for further YHP mechanism research and insights into treating infantile SDD.