Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2001-11-20
pubmed:abstractText
Monoamine oxidase type B (MAO-B) activity and free radicals are elevated in certain neurological diseases. Four natural flavonoids, quercitrin, isoquercitrin, rutin, and quercetin, were isolated for the first time from the leaves of Melastoma candidum D. Don. They exhibited an inhibitory effect on MAO-B. These potent flavonoids were purified using bioassay-guided fractionation and were separated by Diaion, Sephadex LH-20, and MCI CHP20P columns. The IC(50) values of the four potent flavonoids, quercitrin, isoquercitrin, rutin, and quercetin on monoamine oxidase were 19.06, 11.64, 3.89, and 10.89 microM and enzyme kinetics analysis revealed apparent inhibition constants (K(i)) of 21.01, 2.72, 1.83, and 7.95 microM, respectively, on the substrate, benzylamine. The four potent compounds also exhibited hydroxyl radical scavenging activity as determined using a spin trapping electron spin resonance method. This suggests that the four flavonoids from M. candidum possess both MAO-B inhibitory and free radical scavenging activities. These important properties may be used for preventing some neurodegenerative diseases in the future.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-8561
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5551-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Monoamine oxidase B and free radical scavenging activities of natural flavonoids in Melastoma candidum D. Don.
pubmed:affiliation
Graduate Institute of Pharmacognosy Science, Taipei Medical University, Taipei 110, Taiwan. wchou@tmu.edu.tw
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't