title: Inhibition of urease by extracts derived from 15 Chinese medicinal herbs.
abstract: BACKGROUND
  Helicobacter pylori is a major causative factor in gastritis-like disorders, and urease plays a key role in Helicobacter pylori colonizing and persisting in the mucous layer of the human stomach. In China, a variety of Chinese medicinal herbs have been prescribed to attenuate or eradicate gastritis-like disorders. However, little is known about the urease inhibition of Chinese medicinal herbs.
  
  
  OBJECTIVE
  The present study was conducted to investigate the urease inhibition activities of the ethanol and water extracts of 15 Chinese medicinal herbs.
  
  
  METHODS
  The ethanol and water extracts derived from 15 medicinal herbs, traditionally used for the treatment of gastritis-like disorders in China, were tested for urease-inhibition activity using the phenol red method.
  
  
  RESULTS
  Screened at 10 µg/mL, 14 ethanol extracts and 10 water extracts showed urease inhibition. The ethanol extracts of Magnolia officinalis Rehd. et Wils. (Magnoliaceae) and Cassia obtusifolia L. (Leguminosae) possessed inhibition rates higher than 50% with IC₅₀ values of 6.5 and 12.3 µg/mL, respectively. After fractionating successively, the petroleum ether fraction of the ethanol extracts of Magnolia officinalis showed the best activity with 90.8% urease inhibition at a concentration of 10 µg/mL. The bioautography of the petroleum ether fraction indicated the existence of the urease inhibitors in the herb.
  
  
  CONCLUSIONS
  The present results indicated that some Chinese medicinal herbs might treat gastritis-like disorders via the inhibition of Helicobacter pylori urease and the further possibility for discovering useful novel urease inhibitors from the Chinese medicinal herbs.
authors.affiliation: School of Chemical Engineering, Huaihai Institute of Technology, Lianyungang, People's Republic of China. shidahua@yahoo.cn
authors.forename: Da-Hua
authors.initials: DH
authors.lastname: Shi
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Liu
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Liu
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Gu
mesh_terms: D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000431:Ethanol / Q000737:chemistry; D016480:Helicobacter pylori / Q000201:enzymology; D020128:Inhibitory Concentration 50; D012997:Solvents / Q000737:chemistry; D014510:Urease / Q000037:antagonists & inhibitors*; D014867:Water / Q000737:chemistry
chemical_list: D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D012997:Solvents; D014867:Water; D000431:Ethanol; D014510:Urease