Two new lignan glycosides from the seeds of Cuscuta chinensis

Two new lignan glycosides, 2′-hydroxyl asarinin 2′-O-β-D-glucopyranoside (cuscutoside C, 1) and 2′-hydroxyl asarinin 2′-O-β-D-apiofuranosyl-(1 → 2)-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranoside (cuscutoside D, 2), were isolated from the seeds of Cuscuta chinensis Lam., along with six known compounds, 2′-hydroxyl asarinin 2′-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (3), 2′-hydroxyl asarinin 2′-O-β-D-apiofuranosyl-(1 → 2)-β-D-glucopyranoside (cuscutoside A, 4), kaempferol 3,7-di-O-β-D-glucopyranoside (5), 5-caffeoyl quinic acid (6), 4-caffeoyl quinic acid (7), and cinnamic acid (8). Their structures were elucidated on the basis of spectroscopic analyses including HR-ESI-MS, ESI-MS/MS, ¹H and ¹³C NMR, HSQC, HMBC, and TOCSY.