Determinación de la actividad inhibitoria de la fracción alcaloidal de Phaedranassa brevifolia, sobre las enzimas acetilcolinesterasa y butirilcolinesterasa.

Abstract

The objective of the present study was to determine the inhibitory activity of the alkaloidal fraction of Phaedranassa brevifolia, on the acetylcholinesterase enzymes (ACHE) and butyrylcholinesterase (BuChE), taking into account that Phaedranassa brevifolia is an endemic species of Ecuador belonging to the Amaryllidaceae family. From the crude extract obtained by the dry bulb maceration and crushed in methanol, the extraction of alkaloids was carried out by means of a protocol based on pH changes and the use of organic solvents. The determination of the inhibitory activity was developed in based of the Ellman methodology et al with modifications, using galantamina 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 repetitions, each one in triplicate. In addition, the alkaloids present in the sample were identified through the analysis of Gas Chromatography coupled to Mass Spectrometry, which allowed to show the existence of 11 alkaloids, of which there are 4 unidentified compounds, m/z 303; [M=303], m/z 303; [M=273], m/z 109 (homolycorin-type), m/z 125 (homolycorin-type), with significant abundance in m/z 303; [M=303] (33,49%) and 7 identified, pancratinin C, haemantamine, vittatin/crinin, galantamina and the most abundant within this group is 11-hydroxyvittatin / hamayna (18.80%). The obtained results showed that the alkaloidal extract of Phaedranassa brevifolia presented an IC50 of 3,45±0,29 μg/mL for acetylcholinesterase and an IC50 of 58,89±0,55 μg/mL for butyrylcholinesterase, in reference to galantamina that presents IC50 values of 0,30±0,02 μg/mL for Ache and for BuChe an IC50 of 5,00±0,36 μg/mL. In front of both colinestrases, the alkaloidal extract of Phaedranassa brevifolia shows a high inhibitory activity. Finally, it is recommended to carry out more phytochemical studies and biological activity due to the particular phytochemical profile of the species Phaedranassa brevifolia.