The fragmentation of six plumeran indole alkaloids (PIAs) previously isolated from Aspidosperma spruceanum has been investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the positive ion mode. The fragmentation pathways have been established on the basis of MS/MS experiments using fragment ions generated in-source and deuterium-labeled alkaloids as precursor ions and on the basis of accurate mass measurements. Our results demonstrated that the fragmentation routes observed for the protonated PIAs are essentially derived from a pericyclic reaction and from the opening of rings D and E, followed by 1,4-hydrogen rearrangements. Product ions resulting from radical eliminations were also observed, contrary to the 'even-electron rule'. Our data reveals that some product ions from protonated PIAs provide crucial information for the characterization of the acyl substituent at N-1, the methoxyl and hydroxyl groups at the aromatic moiety, and give evidence of an ether bridge between C-18 and C-21. The data reported here were used for the dereplication of these compounds in a stem bark methanolic extract of Aspidosperma spruceanum.

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The new 5-hydroxy-6, 7-dimethoxy-4'-O-(6-O-D-apio-beta-D-furanosyl-beta-D-glucopyranosyl)i soflavone (1) has been isolated from Dalbergia nigra. The structure was elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, UV).

Borreria verticillata contains the new iridoid aglycone borreriagenin (1), in addition to the known iridoids asperuloside (2) and daphylloside (3). The structure of borreriagenin (1) was elucidated by extensive NMR analysis.