Two new lignan glycosides from the seeds of Cuscuta chinensis

Two new lignan glycosides, 2'-hydroxyl asarinin 2'-O--D-glucopyranoside (cuscutoside C, 1) and 2'-hydroxyl asarinin 2'-O--D-apiofuranosyl-(12)-[-D-glucopyranosyl-(16)]--D-glucopyranoside (cuscutoside D, 2), were isolated from the seeds of Cuscuta chinensis Lam., along with six known compounds, 2'-hydroxyl asarinin 2'-O--D-glucopyranosyl-(16)--D-glucopyranoside (3), 2'-hydroxyl asarinin 2'-O--D-apiofuranosyl-(12)--D-glucopyranoside (cuscutoside A, 4), kaempferol 3,7-di-O--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.