A new anthraquinone from seed of Cassia obtusifolia.

Seeds of Cassia obtusifolia L. are known as homology of medicine and food material, which is a commonly consumed beverage in China. One new compound, 8-hydroxy-1,7-dimethoxy-3-methylanthracene-9,10-dione-2-O-β-d-glucoside (1), together with 11 known compounds, including seven anthraquinones (2-8), was isolated from the seeds.