Steroids from the aerial parts of Leonurus japonicus.

Two new steroids, (24 S )-stigmast-4,28-diene-24-ol-3-one ( 1 ) and mono-β-sitosteryl azelate ( 2 ), along with ten known analogues ( 3 – 12 ), were isolated from the ethanolic extract of Leonurus japonicus Houtt. Their structures were elucidated by spectroscopic and chemical methods. The absolute configuration of 1 was confirmed by single crystal X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. Compounds 3 , 4 , and 9 showed significant inhibitory activities against ADP-induced platelet aggregation, while compound 1 had a weak cytotoxic activity against acute myeloid leukemia cell line MV4-11. [ABSTRACT FROM AUTHOR]