Abstract Amaryllidaceae Alkaloids from Zephyrantes Carinata and Their Evaluation as Cholinesterases (AChE and BChE) Inhibitors Karina Sierra 1,*, Natalie Cortés 1,2, Luciana R. Tallini 3,4, Warley de S. Borges 5, Jean Paulo de Andrade 5,6, Jaume Bastida 3 and Edison Osorio Durango 1 1 Grupo de Investigación en Sustancias Bioactivas, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia; [email protected] (N.C.); [email protected] (E.O.D.) 2 Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 calle 67B Av. Ambalá, Ibagué, Colombia 3 Departamento de Biología, Sanidad y Medio Ambiente, Facultad de Farmacia y Ciencias de la Alimentación, Universidad de Barcelona, Av. Joan XXIII, #27-31, Barcelona, España; [email protected] (L.R.T.); [email protected] (J.B.) 4 Programa de pós-graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Av. Ipiranga, 2752, Porto Alegre, Brasil; 5 Departamento de Química, Universidade Federal do Espírito Santo, Avenida Fernando Ferrari, 514, Goiabeiras, Vitória, Espírito Santo, Brazil; [email protected] (W.d.S.B.); [email protected] (J.P.d.A.) 6 Laboratorio de Química de Productos Naturales, Instituto de Química de Recursos Naturales, Universidad de Talca, Talca, Chile * Correspondence: [email protected]; Tel.: +57-311-785-1520 † Presented at the 2nd Molecules Medicinal Chemistry Symposium (MMCS): Facing Novel Challenges in Drug Discovery, Barcelona, Spain, 15–17 May 2019. Published: 12 August 2019 Abstract: The subfamily Amaryllidoideae within of the Amaryllidaceae family has an exclusive group of compounds called Amaryllidaceae alkaloids. Galanthamine, the most known Amaryllidaceae alkaloid, is approved by the FDA as an inhibitor of the enzyme acetylcholinesterase (AChE) for the palliative treatment of Alzheimer Disease (AD). However, butyrylcholinesterase (BChE) contributes critically to cholinergic dysfunction associated with AD. Thus, the development of novel therapeutics may involve the inhibition of both cholinesterase enzymes. Zephyranthes carinata, a species of the Amaryllidaceae family, has been reported to have inhibitory activity against cholinesterases. In order to determine the enzymatic inhibition potential, the major alkaloids of bulbs and leaves of Z. carinata were evaluated in both AChE and BChE. A purification and characterization process was made using different chromatographic and spectrometric techniques, and the inhibitory activity was evaluated with the Ellman method. Alkaloidal extracts of bulbs and leaves exhibited an inhibitory activity with IC50 values of 5.8 ± 0.2 and 8.7 ± 0.3 μg/mL, respectively, against AChE. Further, bulb extract showed IC50 values of 77.9 ± 3.4 μg/mL against BChE. Amaryllidaceae alkaloids hamayne, pseudolycorine, galanthine, criasbetaine, tazettine, lycoramine, hippeastidine, galanthamine, trisphaeridine, 3-epimacronine, haemanthamine, lycorine, and vittatine were purified and evaluated for their AChE and BChE inhibitory activities. Lycoramine (galanthamine type) presented the lowest IC50 value in AChE (17 ± 0.7 μg/mL), and trisphaeridine (narciclasine type) showed the lowest IC50 value in BChE (33.1 ± 3.6 μg/mL). Combined major alkaloids (>10%) were analyzed to observe synergistic behavior. The mixture alkaloids lycoramine and galanthine presented IC50 values of 14.55 ± 1.0 μg/mL against AChE, and the lycoramine, trisphaeridine, and vittatine mix presented IC50 values of 38.42 ± 3.4 μg/mL in BChE. These results Proceedings 2019, 22, 66; doi:10.3390/proceedings2019022066 www.mdpi.com/journal/proceedings Proceedings 2019, 22, 66 2 of 2 showed prominent inhibitory activity against AChE and BChE enzymes, indicating their potential as agents for treating AD through a combined strategy. Keywords: Alkaloids; Amaryllidaceae; Zephyranthes carinata; AChE; BChE © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). .