New lignans from the roots of Valeriana prionophylla with antioxidative and vasorelaxant activities.

Two new 7,9':7',9-diepoxylignan glycosides have been isolated from the roots of Valeriana prionophylla. Their structures have been established on the basis of 1D and 2D NMR experiments as prinsepiol-4-O-beta-D-glucopyranoside (1) and fraxiresinol-4'-O-beta-D-glucopyranoside (2). In addition, 8-hydroxypinoresinol-4'-O-beta-d-glucopyranoside (3), 8-hydroxypinoresinol (4), prinsepiol (5), and chlorogenic acid were isolated. Compounds 1, 3, 4, and 5 were evaluated for their antioxidative properties in Trolox equivalent antioxidant activity (TEAC) and chemiluminescence (CL) assays. The same compounds were tested for their vascular activity in rat aorta rings. The aglycones 4 and 5 displayed powerful antioxidant activity; in addition, aglycone 4 showed a higher vasorelaxant activity than compounds 1, 3, and 5.