Platelet-activating factor (PAF) receptor binding antagonist activity of the methanol extracts and isolated flavonoids from Chromolaena odorata (L.) King and Robinson.
The leaf, stem and root extracts of Chromolaena odorata were evaluated for their effect on platelet-activating factor (PAF) receptor binding on rabbit platelets using 3H-PAF as a ligand. The leaf extract demonstrated high PAF receptor binding inhibitory activity of 79.2+/-2.1% at 18.2 microg/ml. A total of eleven flavonoids were subsequently isolated from the active leaf extract and evaluated for their effects on PAF receptor binding. Eight of the flavonoids exhibited >50% inhibition on the binding activity at 18.2 microg/ml. These flavonoids were identified as eriodictyol 7,4'-dimethyl ether, quercetin 7,4'-methyl ether, naringenin 4'-methyl ether, kaempferol 4'-methyl ether, kaempferol 3-O-rutinoside, taxifolin 4'-methyl ether, taxifolin 7-methyl ether and quercetin 4'-methyl ether. Their IC50 values ranged from 19.5 to 62.1 microM.
Ling
Sui Kiong
SK
Forest Research Institute Malaysia, Selangor Darul Ehsan. lingsk@frim.gov.my
Pisar
Mazura Md
MM
Man
Salbiah
S
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects; D036604:Chromolaena / Q000033:anatomy & histology / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D000432:Methanol / Q000378:metabolism*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors*; D011817:Rabbits; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors*
D005419:Flavonoids; D010936:Plant Extracts; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; D000432:Methanol