Two fast screening methods (GC-MS and TLC-ChEI assay) for rapid evaluation of potential anticholinesterasic indole alkaloids in complex mixtures

Anais da Academia Brasileira de Ciências

Ivo J.c. Vieira²  Walter L.b. Medeiros²  Cecilia S. Monnerat²  Jucimar J. Souza²  Leda Mathias²  Raimundo Braz-filho²  Angelo C. Pinto¹  Priscila M. Sousa¹  Claudia M. Rezende¹  Rosângela De A. Epifanio¹ 

[1] ,Universidade Estadual do Norte Fluminense Darcy Ribeiro Centro de Ciência e Tecnologia Campos dos Goytacazes RJ ,Brasil

关键词: Tabernaemontana;    indole alkaloids;    cholinesterase inhibitor;    thin-layer chromatography assay;    Ellman´s method;    GC-MS;    Tabernaemontana;    alcalóides indólicos;    inibidor colinesterásico;    cromatografia em camada delgada;    método de Ellman;    CG-EM;   

DOI  :  10.1590/S0001-37652008000300003

来源: SciELO

【 摘 要 】

The pharmacotherapyfor 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 Nb-methylvoachalotine for BuChE, and 19-epi-isovoacristine for AChE, whereas olivacine, affinisine, ibogamine, affinine, conodurine and hystrixnineinhibited 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.

【 授权许可】

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