title: Qualitatively and quantitatively investigating the regulation of intestinal microbiota on the metabolism of panax notoginseng saponins.
abstract: BACKGROUND
  Intestinal microflora plays crucial roles in modulating pharmacokinetic characteristics and pharmacological actions of active ingredients in traditional Chinese medicines (TCMs). However, the exact impact of altered intestinal microflora affecting the biotransformation of TCMs remains poorly understood.
  
  
  OBJECTIVE
  This study aimed to reveal the specific enterobacteria which dominate the metabolism of panax notoginseng saponins (PNSs) via exploring the relationship between bacterial community structures and the metabolic profiles of PNSs.
  
  
  METHODS
  2, 4, 6-Trinitrobenzenesulphonic acid (TNBS)-challenged and pseudo germ-free (pseudo GF) rats, which prepared by treating TNBS and antibiotic cocktail, respectively, were employed to investigate the influence of intestinal microflora on the PNS metabolic profiles. Firstly, the bacterial community structures of the conventional, TNBS-challenged and pseudo GF rat intestinal microflora were compared via 16S rDNA amplicon sequencing technique. Then, the biotransformation of protopanaxadiol-type PNSs (ginsenoside Rb1, Rb2 and Rd), protopanaxatriol-type PNSs (ginsenoside Re, Rf, Rg1 and notoginsenoside R1) and Panax notoginseng extract (PNE) in conventional, TNBS-challenged and pseudo GF rat intestinal microbiota was systematically studied from qualitative and quantitative angles based on LC-triple-TOF/MS system. Besides, glycosidases (β-glucosidase and β-xylosidase), predominant enzymes responsible for the deglycosylation of PNSs, were measured by the glycosidases assay kits.
  
  
  RESULTS
  Significant differences in the bacterial community structure on phylum, class, order, family, and genera levels were observed among the conventional, TNBS-challenged and pseudo GF rats. Most of the metabolites in TNBS-challenged rat intestinal microflora were identified as the deglycosylation products, and had slightly lower exposure levels than those in the conventional rats. In the pseudo GF group, the peak area of metabolites formed by loss of glucose, xylose and rhamnose was significantly lower than that in the conventional group. Importantly, the exposure levels of the deglycosylated metabolites were found have a high correlation with the alteration of glycosidase activities and proteobacteria population. Several other metabolites, which formed by oxidation, dehydrogenation, demethylation, etc, had higher relative exposure in pseudo GF group, which implicated that the up-regulation of Bacteroidetes could enhance the activities of some redox enzymes in intestinal microbiota.
  
  
  CONCLUSIONS
  The metabolism of PNSs was greatly influenced by intestinal microflora. Proteobacteria may affect the deglycosylated metabolism of PNSs via regulating the activities of glycosidases. Besides, up-regulation of Bacteroidetes was likely to promote the redox metabolism of PNSs via improving the activities of redox metabolic enzymes in intestinal microflora.
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Dian
authors.initials: D
authors.lastname: Kang
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Yuhao
authors.initials: Y
authors.lastname: Shao
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Boyu
authors.initials: B
authors.lastname: Shen
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Xinuo
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Yin
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Zhangpei
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Haofeng
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Tai
authors.initials: T
authors.lastname: Rao
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xie
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China. Electronic address: liangyan0679@hotmail.com.
authors.forename: Guangji
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Lab of Drug Metabolism & Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Tongjiaxiang 24, Nanjing 210009, China. Electronic address: liangyan0679@hotmail.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
mesh_terms: D000818:Animals; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology*; D008297:Male; D064307:Microbiota; D053723:Panax notoginseng / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000378:metabolism*
chemical_list: D012503:Saponins
keywords: Deglycosylation; Glycosidase; Intestinal microflora; Panax notoginseng extract; Panax notoginseng saponin