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

• Published in: Phytomedicine (Stuttgart) Vol. 10; no. 8; pp. 650 - 656
• Main Authors: Lin, R.-D., Hou, W.C., Yen, K.Y., Lee, M.H.
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01.11.2003; Urban & Fischer Verlag; Elsevier Science Ltd
• Subjects: Animals; Arisaema; Arisaema amurense; Case studies; Drugs, Chinese Herbal - administration & dosage; Drugs, Chinese Herbal - pharmacology; Drugs, Chinese Herbal - therapeutic use; Health aspects; Inhibitory Concentration 50; Lilium; Lilium brownii var. colchesteri; Lycium; Lycium chinense; Male; Monoamine oxidase; Monoamine oxidase (MAO); Monoamine Oxidase - drug effects; Monoamine Oxidase Inhibitors - administration & dosage; Monoamine Oxidase Inhibitors - pharmacology; Monoamine Oxidase Inhibitors - therapeutic use; Phytotherapy; Plants, Medicinal; Rats; Rats, Wistar; Uncaria; Uncaria rhynchophylla; Taiwan; Lilium brownii var. colchesteri; Monoamine oxidase (MAO); Arisaema amurense; Lycium chinense; Uncaria rhynchophylla
• ISSN: 0944-7113; 1618-095X
• DOI: 10.1078/0944-7113-00324

Monoamine oxidase (MAO) catalyzes the oxidative deamination of biogenic amines accompaned by the release of H 2O 2. 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 IC 50 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 IC 50 concentrations, and results show that: K i = 0.59 mg/ml for A. amurense for the mixed-type mode, K i = 0.58 mg/ml for L. brownii var. colchesteri for the mixed-type mode, K i = 5.01 mg/ml for L. chinense for the uncompetitive mode, and K i = 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.