菌群失调下的人参总皂苷胃肠道代谢处置差异表征及机制研究

Gut microbita mediated deglycosylation of most saponins from Chinese medicine is a critical step for achieving their pharmacological effects. Thus, we hypothesized that gut microbiota dysbiosis may influence the pharmacokinetics, metabolism and disposition of the saponins, ultimately affecting their pharmacological efficacy. In this project，total ginsenoside were selected as the model drug and rat model of microbiota dysbiosis induced by chronic restrain stress and treatment of antibiotics was applied. Firstly, the pharmacokinetics, urine and fecel excretion profiles of the ginsenoside and its metabolites were simultaneously studied using a qualitative and quantitative method based on LC-Q-TOF/MS. The intervention effects of the probiotcs on the metabolism and disposition of ginsenosides in gut microbiota dysbiosis rat were also studied. The glycosidase activity, the epression of tight junction protein (ZO-1, Occludin) and the efflux transporter like P-gp were also investigated to illustrate the potential mechanisms involved in the pharmacokinetic difference of gisenosides between the normal and dysbiotic rat. Finally, the DGGE-PCR and Real time-PCR technique were applied to study the structural shift of the gut microbiota and establish the correlation between the composition of gut microbiota and the glycosidase activity. Our result may provide a novel and general strategy for studying the effcts of gut microbiota dysbiosis on the pharmacokinetics profiles of total ginsenosides and other saponins.

中药皂苷类成分经肠道菌群脱糖基代谢与其药效发挥密切相关，肠道菌群失调可能引起中药皂苷类成分胃肠道代谢处置改变，进而影响其药效发挥。本项目拟以人参总皂苷为模型药，在慢性束缚性应激和抗生素诱导的肠道菌群失调模型大鼠上，基于LC-Q-TOF/MS同时定性定量技术，系统表征人参总皂苷在菌群失调下的体内代谢转化和尿、粪排泄差异，并探讨微生态制剂干预菌群失调后人参皂总皂苷的体内代谢处置转归；从各肠段糖苷酶活性、紧密连接蛋白和P-gp等外排转运体的角度，深入研究引起人参总皂苷胃肠道代谢处置差异的可能机制；此外，应用PCR-DGGE、实时定量PCR等技术研究肠道菌群失调下的菌群结构谱变化，将其与糖苷酶活性相关联。本项目在为诠释肠道菌群失调对人参总皂苷代谢处置及其作用机制的同时，还为其他皂苷类成分在肠道菌群失调下体内代谢处置差异机制提供共性研究思路与方法。

本项目以人参皂苷为模型药物，在慢性束缚性应激和抗生素诱导的肠道菌群失调模型大鼠上，从肠道菌群组成、肠道菌群功能、活性等角度研究引起人参总皂苷胃肠道代谢处置差异的可能机制。研究结果表明抗生素（纳他霉素、新霉素和短杆菌肽）可显著改变肠道菌群的结构，尤其是益生菌的比例，进而影响胃肠道中短链脂肪酸的浓度及糖苷酶的活性。从三组大鼠的血浆分析结果看出：应激组和抗生素组大鼠血浆中的人参皂苷Rb1、Rb2/Rb3和Rc的AUC(0-t) 值均高于正常组，人参皂苷Rd的AUC(0-t)值低于正常组。大鼠粪便排泄结果表明抗生素组中人参皂苷Rb1、Rb2/Rb3和Rc的粪便累积排泄量明显高于正常组，而脱糖基产物Rg3、Rd、C-K和F1的排泄量显著低于正常组，这可能是由于大鼠灌服抗生素后，肠道内糖苷酶活性降低，抑制了人参皂苷Rb1、Rb2/Rb3、 Rc等的生物转化。在应激组中，Rb1和Rg1的粪便累积排泄量显著低于正常组，而C-K的粪累计排泄量高于正常组。上述研究结果提示在菌群失调状态下，口服人参总皂苷后，体内人参皂苷的质及量可发生改变，进而影响其效应的发挥，基于人参皂苷较高的粪排泄，尤其应关注其菌群失调状态下对胃肠道疾病效应的影响。.研究内容已发表论文10篇，其中中文核心期刊论文8篇，SCI收录论文2篇，培养硕士研究生1名。.