Isoflavonoids Isolated from Cuban Propolis

摘要

Chemical investigation of a red-type Cuban propolis sample has led to the isolation of 11 isoflavonoids(2 isoflavones,3 isoflavans,and 6 pterocarpans),together with gallic acid,isoliquiritigenin,and(-)-liquiritigenin.Structural determination,including the absolute stereochemistry,was accomplished by spectroscopic analysis,particularly CD and 2D NMR techniques.The fragmentation behavior of pterocarpans was studied by electrospray ionization(ESI)tandem mass spectrometry(MS/MS)using an ion-trap analyzer,and a generalized fragmentation pathway,useful in the identification and structural characterization of pterocarpans,is proposed.Isoflavonoids are reported for the first time from propolis samples.