Two new anthraquinone glycosides from the roots of Rheum palmatum.

Two new anthraquinone glycosides, named 1-methyl-8-hydroxyl-9,10-anthraquinone-3-O-ß-D-(6'-O-cinnamoyl)glucopyranoside (1) and rhein-8-O-ß-D-[6'-O-(3''-methoxyl malonyl)]glucopyranoside (2), have been isolated from the roots of Rheum palmatum, together with seven known compounds, rhein-8-O-ß-D-glucopyranoside (3), physcion-8-O-ß-D-glucopyranoside (4), chrysophanol-8-O-ß-D-glucopyranoside (5), aleo-emodin-8-O-ß-D-glucopyranoside (6), emodin-8-O-ß-D-glucopyranoside (7), aleo-emodin-ω-O-ß-D-glucopyranoside (8), and emodin-1-O-ß-D-glucopyranoside (9). Their structures were elucidated on the basis of chemical and spectral analysis.