Two new phenylpropanoid glycosides from the roots of Aruncus sylvester.

Two new phenylpropanoid glycosides, 1,3,4-tri-O-(E)-caffeoyl-β-d-glucopyranoside (1) and 1,4-di-O-(E)-caffeoyl-β-d-glucopyranoside (2), along with four known phenylpropanoid glycosides (3-6), were isolated from the roots of Aruncus sylvester. The structures of 1 and 2 were elucidated using various spectroscopic methods. Compounds 1 and 2 displayed significant scavenging activity of 2,2-diphenyl-1-picrylhydrazyl free radicals with IC50 values of 110 and 258 μM (ascorbic acid: IC50 = 574 μM).