Inhibition of monoamine oxidase B (MAO-B) by Chinese herbal medicines

R. D. Lin, W. C. Hou, K. Y. Yen, M. H. Lee

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


Monoamine oxidase (MAO) catalyzes the oxidative deamination of biogenic amines accompaned by the release of H2O2. Two subtypes, MAO-A and MAO-B, exist on the basis of their specificities to substrates and inhibitors. The regulation of MAO-B activity is important in the treatment of neurodegenerative diseases. Twenty-seven species of plants used in traditional Chinese medicines, selected from an enthnobotanical survey, were used in an investigation of their inhibitory effect on MAO-B in rat brain homogenates. The 50% aqueous methanol extracts of four active extracts, Arisaema amurense, Lilium brownii var. colchesteri, Lycium chinense, and Uncaria rhynchophylla, exhibited the best activity and selectivity towards MAO-B with IC50 values of 0.44, 0.29, 0.40, and 0.03 mg/ml, respectively. A kinetic study of MAO-B inhibition by the four extracts using the Lineweaver-Burk plot for each active extract revealed the IC50 concentrations, and results show that: Ki = 0.59 mg/ml for A. amurense for the mixed-type mode, Ki = 0.58 mg/ml for L. brownii var. colchesteri for the mixed-type mode, Ki = 5.01 mg/ml for L. chinense for the uncompetitive mode, and Ki = 0.02 mg/ml for U. rhynchophylla for the uncompetitive mode. These may therefore be candidates for use in delaying the progressive degeneration caused by neurological diseases.

Original languageEnglish
Pages (from-to)650-656
Number of pages7
Issue number8
Publication statusPublished - Nov 2003


  • Arisaema amurense
  • Lilium brownii var. colchesteri
  • Lycium chinense
  • Monoamine oxidase (MAO)
  • Uncaria rhynchophylla

ASJC Scopus subject areas

  • Drug Discovery
  • Molecular Medicine
  • Complementary and alternative medicine
  • Pharmacology
  • Pharmaceutical Science


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