Chingazumianine, a novel dichlorinated alkaloid from Corydalis koidzumiana

A dichlorinated alkaloid with a novel skeleton, chingazumianine (1), was is olated from the herb Corydalis koidzumiana, and its structure elucidated by spectroscopic data and X-ray crystallographic analysis. In citrate-treated human platelet-rich plasma (PRP), known compounds, ie., protopine (2), (+/ -)-tetrahydropalmatine (3), and palmatine (4), isolated from this plant, sh owed significant inhibition of secondary aggregation induced by adrenaline in a concentration-dependent manner, suggesting that the antiplatelet effec ts of these compounds is mainly due to an inhibitory effect on thromboxane formation.