Antiplatelet Aggregation Coumarins from the Leaves of Murraya omphalocarpa

Using a bioactivity-guided fractionation method, two coumarins: minumicrolineacetonide (1) and epimurpaniculol senecioate (2), were isolated from the leaves ofMurraya omphalocarpa Hayata (Rutaceae). Compound 1 had been previously synthesizedand was now isolated from natural sources for the first time, and compound 2, possessing anegative optical rotation value, is new. The structures and their stereochemistry were fullyelucidated on the basis of spectroscopic and X-ray crystallographic techniques. Bothcompounds 1 and 2 are active in the antiplatelet aggregation assay. Interestingly, thepossible acetonide artifact 1 displayed significant antiplatelet aggregation induced not onlyby AA and collagen but also by platelet activating factor (PAF).