Acetylcholinesterase-inhibiting Alkaloids from Zephyranthes concolor oleh Sebastien Arseneau, Carles Codina, Jaume Bastida, Francesc Viladomat, José A. Esté, Imma Clotet-Codina, Christopher K. Jankowski, Simón Hernández-Ortega, Strahil Berkov, Ricardo Reyes-Chilpa