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.

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).

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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.

Atividade biológica e alcalóides indólicos do gênero Aspidosperma (Apocynaceae): uma revisão RESUMO:Embora sejam conhecidas principalmente como fonte de madeira nobre para aplicação na construção de móveis, as espécies do gênero Aspidosperma apresentam muitos estudos na área da fitoquímica e poucos estudos na área da farmacologia. As espécies do gênero Aspidosperma são largamente aplicadas por populares como potenciais agentes antimaláricos, no tratamento da leishmaniose, de inflamações do útero e ovário, como anticonceptiva, em diabetes e em problemas estomacais, contra câncer, febre e reumatismo. Do ponto de vista químico, a grande maioria das espécies constituintes do gênero já foi submetida a algum estudo de isolamento e identificação dos alcalóides indólicos presentes nas mais diversas partes das plantas. Já do ponto de vista farmacológico poucos testes foram realizados até então para justificar a grande aplicação das mesmas por populares e a importância dos alcalóides indólicos presentes nas representantes do gênero. Visando contribuir para um maior conhecimento sobre a importância da presença dos alcalóides indólicos no gênero Aspidosperma e sua relação com as atividades farmacológicas atribuídas ou testadas, é que apresentamos uma revisão das principais publicações envolvendo estudos químicos e biológicos do gênero Aspidosperma. Palavras-chave: Aspidosperma, alcalóides indólicos, atividade biológica, etnofarmacologiaABSTRACT: Biological activity and indole alkaloids of the genus Aspidosperma (Apocynaceae): a review. Although mainly known as source of noble wood for furniture construction, species of the genus Aspidosperma have been extensively studied in Phytochemistry but scarcely investigated in Pharmacology. Aspidosperma species have been commonly used in folk medicine as potential antimalarial agents; in the treatment of leishmaniasis, and uterus and ovary inflammations; as contraceptive; in diabetes and stomach disorders; and against cancer, fever and rheumatism. From a chemical point of view, the great majority of Aspidosperma species have already been subjected to isolation and identification of indole alkaloids present in their several parts. From a pharmacological point of view, few tests have been carried out so far to justify the great applicability of these species in folk medicine besides the importance of the indole alkaloids present in the genus representatives. Aimed at improving the knowledge on the importance of indole alkaloids in the genus Aspidosperma and their relationship with attributed or tested pharmacological activities, we present a review of the main reports involving chemical and biological studies on the genus Aspidosperma.

A phytochemical study on Borreria verticillata has led to the isolation of two novel simple indole alkaloids, 6‐methoxy‐4‐(3‐methylbut‐2‐en‐1‐yl)‐1H‐indole, named verticillatine A (1), and 1‐(1H‐indol‐6‐yl)‐3‐methylbutan‐1‐one, named verticillatine B (2), one new iridoid, 6′‐O‐(2‐glyceryl)scandoside methyl ester (3), with the glycerol unit linked to a glucose unit, and two known ones, asperuloside (4) and scandoside methyl ester (5). The structures of these compounds were elucidated on the basis of spectroscopic‐data analyses, mainly 1H‐ and 13C‐NMR, including 2D experiments (1H,1H‐COSY, NOESY, HMBC, and HMQC), and HR‐ESI‐MS.

Um novo alcalóide, denominado histrixnina (1), e cinco alcalóides indólicos conhecidos, ibogamina (2), olivacina (3) e affinina (4), affinisina (5) e N b -metilaffinisina (6), foram isolados do extrato metanólico das cascas das raízes de Tabernaemontana hystrix. Os triterpenos conhecidos 3-O-acetil-α-amirina, 3-O-acetil-β-amirina, 3-O-acetil-lupeol foram também identificados. As estruturas dos compostos foram elucidadas com base na análise de dados espectroscópicos.A new alkaloid, named hystrixnine (1), and five known indole alkaloids, ibogamine (2), olivacine (3), affinine (4), affinisine (5) and N b -methylaffinisine (6), were isolated from the root bark of Tabernaemontana hystrix. The known triterpenes α-amyrin acetate, β-amyrin acetate and lupeol acetate were also identified. The structures of the compounds were elucidated based on spectroscopic studies.

The pharmacotherapy for Alzheimer's disease (AD) includes the use of acetylcholinesterase inhibitors (AChEI). Recent investigations for novel AD therapeutic agents from plants suggested that Tabernaemontana genus is a promising source of novel anticholinesterasic indole alkaloids. In this work two fast screening techniques were combined in order to easily identify novel cholinesterase inhibitors (ChEI). Gas chromatography-mass spectrometry (GC-MS) of the less polar alkaloidic fractions obtained from the acid-base extraction of the stalk of T. laeta revealed thirteen monoindole alkaloids, four of them confirmed by co-injection with previously isolated alkaloids. The others were tentatively identified by mass fragmentation analysis. By gas chromatography with flame ionization detection (GC-FID) and using isatin as internal standard, affinisine and voachalotine were determined as major compounds. These fractions and fourteen previously isolated alkaloids, obtained from root bark of T. laeta and T. hystrix were investigated for acetyl (AChE) and butyrylcholinesterase (BuChE) inhibitory activities by the modified Ellman's method in thin layer chromatography (TLC-ChEI). Results showed selective inhibition of the alkaloids heyneanine and N b -methylvoachalotine for BuChE, and 19-epi-isovoacristine for AChE, whereas olivacine, affinisine, ibogamine, affinine, conodurine and hystrixnine inhibited both enzymes. In addition to confirming that monoterpenoid indole alkaloids can be novel therapeutic agents for AD, this is the first report of the ChEI activity of olivacine, a pyridocarbazole alkaloid.