Effect of Tong Xie Yao Fang on endogenous metabolites in urine of irritable bowel syndrome model rats

BACKGROUND: Tong Xie Yao Fang is a representative traditional Chinese prescription for the treatment of liver and spleen deficiency, abdominal pain and diarrhea. It has a unique function in the treatment of gastrointestinal dysfunction including irritable bowel syndrome (IBS), is a common functional bowel disease. Its main symptoms are recurrent abdominal pain, diarrhea, constipation or alternations between diarrhea and constipation. There are obvious differences in metabolites between TCM syndromes. By comparing the body fluid metabolism maps of model animals, metabolomics can discover disease biomarkers, analyze the differences in metabolic pathways and understand the pathological process and the metabolic pathways of substances in the body. Thus, the evaluation of animal models tends to be comprehensive and objective. This may provide further understanding between the interaction between Tong Xie Yao Fang and the IBS model. AIM: To evaluate the effect of Tong Xie Yao Fang on IBS rats by using metabolomics method. METHODS: Wistar rats were used to establish IBS models, and then randomly divided into four groups: A model control group and three Tong Xie Yao Fang treatment groups (high, medium and low doses). A normal, non-IBS group was established. The rats were treated for 2 wk. On days 0 and 14 of the experimental model, urine was collected for 12 h and was analyzed by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry. Nine potential biomarkers were identified, and six major metabolic pathways were found to be related to IBS. RESULTS: In the study of metabonomics, nine potential biomarkers including L-serine, 4-methylgallic acid, L-threonine, succinylacetone, prolyl-hydroxyproline, valyl-serine, acetyl citrate, marmesin rutinoside and 5-hydroxy-L-tryptophan were identified in urine, which were assigned to amino acids, organic acids, succinyl and glycosides. Furthermore, the metabolic pathway of L-serine, L-threonine and 5-hydroxy-L-tryptophan was found in the Kyoto Encyclopedia of Genes and Genomes, which mainly involved the metabolism of cysteine and methionine, vitamin B6 metabolism, serotonin synapse, tryptophan metabolism, sphingolipid metabolism, digestion, absorption of protein and amino acid metabolism. These pathways are related to intestinal dysfunction, inflammatory syndrome, nervous system dysfunction and other diseases. CONCLUSION: Tong Xie Yao Fang has pharmacological effects on IBS, and its mechanism may be related to the metabolism of the nine potential biomarkers identified above in urine.