title: Deglycosylation of isoflavone C-glycosides by newly isolated human intestinal bacteria.
abstract: BACKGROUND
  Plant isoflavones are mostly present in the glycoside form. Isoflavone aglycones produced by intestinal microflora are reported to be more bioactive than the glycoside form. However, the deglycosylation of isoflavone C-glycosides is known to be rare, and is less studied.
  
  
  RESULTS
  Three new bacteria were isolated from human faecal samples, two of which hydrolysed the C-glycosidic bond of puerarin, daidzein-8-C-glucoside. They were identified as two Lactococcus species, herein designated as MRG-IFC-1 and MRG-IFC-3, and an Enterococcus species, herein designated MRG-IFC-2, based on their 16S rDNA sequences. From a reactivity study, it was found that Lactococcus sp. MRG-IFC-1 and Enterococcus sp. MRG-IFC-2 hydrolysed isoflavone C- and O-glycosides, as well as the flavone O-glycoside apigetrin, but could not hydrolyse the flavone C-glycosidic bond of vitexin. The other Lactococcus sp., MRG-IF-3, could not hydrolyse the C-glycosidic linkage of puerarin, while it showed a broad substrate spectrum of O-glycosidase activity similar to the other two bacteria. Puerarin was completely converted to daidzein within 100 min by Lactococcus sp. MRG-IFC-1 and Enterococcus sp. MRG-IFC-2, which is the fastest conversion among the reported human intestinal bacteria.
  
  
  CONCLUSIONS
  Two new puerarin-metabolising human intestinal bacteria were isolated and identified, and the deglycosylation activity for various flavonoid glycosides was investigated. The results could facilitate the study of C-glycosidase reaction mechanisms, as well as the pharmacokinetics of bioactive C-glycoside natural products.
authors.affiliation: Metalloenzyme Research Group and Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea.
authors.forename: Mihyang
authors.initials: M
authors.lastname: Kim
authors.affiliation: Metalloenzyme Research Group and Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea.
authors.forename: Jaekwan
authors.initials: J
authors.lastname: Lee
authors.affiliation: Metalloenzyme Research Group and Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea.
authors.forename: Jaehong
authors.initials: J
authors.lastname: Han
mesh_terms: D000328:Adult; D047310:Apigenin / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D016983:Enterococcus / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D006868:Hydrolysis; D007422:Intestines / Q000382:microbiology*; D007529:Isoflavones / Q000378:metabolism*; D007700:Kinetics; D017045:Lactococcus / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D058889:Molecular Typing; D056910:Republic of Korea; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D006027:Glycosides; D007529:Isoflavones; C057792:apigetrin; D047310:Apigenin; D006026:Glycoside Hydrolases; C033607:puerarin
keywords: deglycosylation; human intestinal bacteria; isoflavone C-glycoside; isoflavone O-glycoside; puerarin