Study On The Interaction Between The Petroleum Ether Fraction Of Radix Bupleurum And Gut Microbiota Of CUMS Rats

RATIONALES: Depression is a mental illness characterized by low mood,d pathogenesis are not clear.Recent studies have found that imbalance of gut microbiota is closely related to the occurrence and development of depression.Traditional Chinese medicine(TCM)is usually administered orally,the active components of TCM will inevitably contact with gut microbiota after arriving in the gastrointestinal tract.On the one hand,the active ingredients of TCM can regulate the structure and metabolism of the gut microbiota,and on the other hand,the gut microbiota can convert the active ingredients of the drug into corresponding pharmacological or toxicological components.In vivo and in vitro pharmacological activities of each part of XYS were studied in our previous work,and it was found that the anti-depression effect of the petroleum ether fraction was the strongest,and the effect was better than the original prescription.And further studies showed that the petroleum ether fraction of Bupleuri Radix(PBR)has an antidepressant effect.However,the pharmacodynamic basis and mechanism of PBR based on gut microbiota action have not been clarified.Objective: The study on interactions between PBR and gut microbiota are helpful to provide experimental basis for revealing the basis of the medicinal substance and the mechanism of action of PBR based on the gut microbiota.Methods: 1.LC-MS technology was used to comprehensively characterize the chemical constituents of PBR,providing a basis for further elucidation of pharmacodynamic material basis.2.To establish a model of chronic mild and unpredictable stress(CUMS)in rats.PBR was incubated and anaerobic condition with normal and CUMS model rats gut microbiota respectively.LC-MS was applied to analyze the metabolites.3.16 S r RNA gene sequencing technology was used to investigate the effects of PBR on gut microbiota in CUMS-induced depression4.LC-MS metabolomics was used to investigate the effects of PBR on gut microbiota metabolites in CUMS-induced depression.Results: 1.A total of 58 compoents,including 16 saikosaponins?10 coumarin?8Bupleurum polyacetylene?8 lignanoid?8 fatty acid?4 flavone?2 chromone?1 uracil and1 xylitol were identified based on LC-MS in PBR.The results basically clarified the material basis of PBR.2.The normal rat gut microbiota could convert the active ingredients of PBR into oxidation,oxidation,methylation metabolite;oxidation,ornitine conjugation metabolite;dehydration,arginine conjugation metabolite;hydration,reduction metabolite;arginine conjugation metabolite;hydration,oxidation metabolite.Metabolites of the active ingredient of PBR in the gut microbiota of CUMS model rats are basically consistent with normal rats,which may be due to the gut microbiota of the normal rats was the same as the main gut microbiota composition of the gut microbiota of the CUMS model rats.There was a big difference between the gut microbiota of normal rats and the gut microbiota of CUMS model rats on the metabolic capacity of PBR.The metabolic rate of the active components in the PBR was significantly higher in the CUMS model rats than that of normal rats,which may be due to the imbalance of gut microbiota caused by depression.3.PBR could increase the diversity of gut microbiota in CUMS rats and significantly restored the relative abundance of [Prevotella],Rothia,Cupriavidus,Ochrobactrum and Lachnobacterium with effects on immunity,inflammation,vitamin D deficiency,and short-chain fatty acids.4.Cecal content metabolomics identified twenty biomarkers that were altered by depression,whereas administration of PBR ameliorated the changes in sixteen metabolites.The pathways involved include primary bile acid biosynthesis,taurine and hypotaurine metabolism,arginine and proline metabolism,citrate cycle(TCA cycle),glyoxylate and dicarboxylate metabolism.Conclusion: The metabolism of PBR by gut microbiota was closely related to the treatment of depression.On the one hand,the gut microbiota has the function of biotransformation on the active ingredients of PBR.On the other hand,PBR may exert antidepressant effects by regulating the composition of the gut microbiota and the metabolites.