Electrospray ionization mass spectrometry screening of piperidine alkaloids from Senna spectabilis (Fabaceae) extracts: fast identification of new constituents and Co-metabolites - Pivatto, Marcos; Crotti, Antonio Eduardo Miller; Lopes, Norberto Peporine; Castro-Gamboa, Ian; Rezende, Amanda de; Viegas Júnior, Cláudio; Young, Maria Cláudia M.; Furlan, Maysa; Bolzani, Vanderlan S. (Journal of Brazilian Chemical Society, 2005)