Constituents from Rubia ustulata Diels and R. yunnanensis Diels and their antiplatelet aggregation activity

A new anthraquinone glycoside, rubiayannone-A (1), and a new coumarin, rubilatin-A (2), together with twenty-two known compounds were isolated and characterized from the roots of Rubia ustulata. A new anthraquinone, 2-carbomethoxyanthraquinone (3), and rubiayannone-A, 2-formylanthraquinone were obtained from the roots of R. yunnanensis. The structures of those compounds were elucidated by spectroscopic methods. The antiplatelet aggregation activity of the isolated compounds 1,4-6 were also discussed.