ISOLATION AND CHARACTERIZATION OF PLATELET-ACTIVATING-FACTOR RECEPTOR-BINDING ANTAGONISTS FROM BIOTA-ORIENTALIS

The leaf extract of Biota orientalis showed potent PAF receptor bindin g antagonistic activity in our previous screening studies on 234 Korea n medicinal plants using rabbit platelet receptor binding tests. The a ctivity-guided purification of the plant extract resulted in the isola tion of six compounds, including two active substances. The chemical s tructures of the compounds isolated were established by chemical and s pectrometric analyses as dotriacontane, totarol, 8 beta-hydroxy-3-oxop imar-15-ene, cedrol (IC50 = 1.3 x 10(-5) M), pinusolide (IC50 = 2.52 x 10(-7) M), and 5-hydroxy-7,4'-dimethoxyflavone.