Pinusolidic acid: a platelet-activating factor inhibitor from Biota orientalis

The water extract of Biota orientalis showed a potent inhibitory effect on platelet activating factor (PAF) binding to rabbit platelets using [ (3)H]PAF as a ligand in our previous screening studies for Korean medicinal antagonists by the activity-guided purification studies. Another active compound, compound 1 (IC (50) = 2.3 x 10 (-5)M, 7.48 +/- 2.11 microg/ml, n = 4) was isolated from the title plant. The chemical structure of compound 1 was elucidated as pinusolidic acid by chemical and spectrometric analyses.