Evaluación de la actividad inhibitoria de acetilcolinesterasa y butirilcolinesterasa del extracto alcaloidal de Phaedranassa tunguraguae.

Abstract

The objective was to evaluate the inhibitory activity of acetylcholinesterase and butyrylcholinesterase of the alkaloidal extract of the Phaedranassa tunguraguae bulb, an endemic species of Ecuador belonging to the Amaryllidaceae family. From the crude extract obtained by maceration of the bulb with methanol, the extraction of alkaloids was carried out by a method based on pH changes and the use of organic solvents. In addition, alkaloids present in the sample were identified through Gas Chromatography coupled to Mass Spectrometry. In addition, the evaluation of the inhibitory activity of the alkaloidal extract against the enzymes acetylcholinesterase and butyrylcholinesterase was carried out using the Ellman method with modifications, using galantamine as a reference compound. Enzymatic inhibition curves were made and from the equation of the obtained line the IC50 was calculated as an average of three individual repeats, each in triplicate. In the extract of alkaloids of P. tunguraguae the presence of 15 alkaloids was detected, being identified only 8 of them. Lycorine (46.97%) was the most abundant alkaloid, and the presence of 7 unidentified alkaloids was determined with m/z 109, m/z 275, m/z 228, m/z 240, m/z 284, and m/z 294. The enzymatic inh ibitory activity of alkaloid extract expressed with IC50 (concentration at which 50% inhibition occurs), was for acetylcholinesterase of IC50 11.12 ± 1.87 ug/mL, lower activity compared with galantamine (IC50 0.30 ± 0.01 ug/mL). On the other hand, for butyrylcholinesterase obtained an IC50 of 64.49 ± 1.34 ug/mL, against galantamine IC50 4.31 ± 0.04 ug/mL. These results show that the alkaloid extract of P. tunguraguae has less inhibitory activity than galantamine, but relatively untouchable, showing greater affinity of the alkaloids for AChE. It is recommended to carry out more phytochemical and biological activity studies of the species Phaedranassa tunguraguae.