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.