title: Role of intestinal hydrolase in the absorption of prenylated flavonoids present in Yinyanghuo.
abstract: OBJECTIVE
  Yinyanghuo (Herba Epimdii) is a traditional Chinese herb containing prenylated flavonoids as its active constituents. The aim of this study was to examine the significance of the intestinal hydrolysis of prenylated flavonoids by lactase phlorizin hydrolase (LPH), an enzyme at the brush border membrane of intestinal cells.
  
  
  METHODS
  A four-site perfused rat intestinal model was used. The concentration of the flavonoids of interest and their metabolites in different intestinal segements were analyzed by HPLC, and the apparent permeabilities were calculated. A lactase phlorizin hydrolase inhibitor (gluconolactone) was employed to investigate the mechanism of the intestinal absorption, and the metabolites of the four flavonoids were identified using LC/MS/MS.
  
  
  RESULTS
  Diglycosides (icariin) or triglycosides (epimedin A, epimedin B, and epimedin C) were hydrolyzed rapidly in duodenum and jejunum producing one or two metabolites, while a monoglycoside (baohuoside I) was absorbed directly. When co-perfused with glucono-lactone, both the hydrolysis of diglycosides and triglycosides were significantly inhibited, with inhibition rates for icariin (62%, 50%, 40%, 46%), epimedin A, (55%, 26%, 21%, 14%); epimedin B (42%, 40%, 74%, 22%), and epimedin C (42%, 40%, 52%, 35%) in duodenum, jejunum, ileum, and colon, respectively. Also the metabolites of icariin, epimedin A, epimedin B, and epimedin C were identified as baohuoside I (one of two), sagittatoside A, sagittatoside B, and 2"-O-rhamnosylicariside II, respectively.
  
  
  CONCLUSIONS
  The results showed that lactase phlorizin hydrolase was a major determinant of the intestinal absorption of prenylated flavonoids present in Yinyanghuo.
authors.affiliation: Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, 100 Shizi Road, Nanjing 210028, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Jinyan
authors.initials: J
authors.lastname: Wang
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Jia
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Tan
authors.forename: Ming
authors.initials: M
authors.lastname: Hu
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism*; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism; D007408:Intestinal Absorption / Q000502:physiology*; D007422:Intestines / Q000201:enzymology*; D010694:Lactase-Phlorizin Hydrolase / Q000378:metabolism*; D008297:Male; D015394:Molecular Structure; D051381:Rats; D017207:Rats, Sprague-Dawley; D053719:Tandem Mass Spectrometry
chemical_list: D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D006027:Glycosides; C046314:epimedii flavone; D010694:Lactase-Phlorizin Hydrolase