Lignans from the Aerial Parts of Saururus chinensis: Isolation, Structural Characterization, and Their Effects on Platelet Aggregation

Five new diaryldimethylbutane lignans, saurulignans A E (1-5), four new tetrahydrofuran lignans, saurufurins A D (6-9), and one arylnaphthalene lignan, saurunarin (10), were isolated from Saururus chinensis, along with 18 known compounds. Lignan 5 showed significant inhibition of ADP-induced aggregation with an IC50 value of 9.8 mu M and AA-induced aggregation with an IC50 value of 14.0 mu M Compound 19 showed significant activity to inhibit PAP-induced aggregation with an IC50 value of 9.1 mu M. In addition, five isolated compounds could induce platelet aggregation. These results suggest that secondary metabolites in S. chinensis have bidirectional regulation on blood clotting and anticlotting effects.