Determinación de la actividad inhibitoria de acetilcolinesterasa y butirilcolinesterasa del extracto de alcaloides de Phaedranassa dubia.

Abstract

The research aimed to determine the inhibitory activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of the alkaloids extract from plant species Phaedranassa dubia, belonging to the Amaryllidaceae family. From the gross extract obtained by maceration in methanol of the dry and shredded bulb was used a protocol for extraction of alkaloids based on changes of pH and organic solvents use. Gas Chromatography coupled to Mass Spectrometry (CG-EM) was applied with the objective of identifying the alkaloids present in the bulb of Phaedranassa dubia and determining their respective percentages. (GC-MS). The inhibitory activity was determined on the basis of the modified methology of Ellman et al., using galanthamine as a reference compound. The employed method had to be developed based on the physical, environmental and equipment characteristics of the laboratory used, for the subsequent obtaining the half maximal inhibitory concentration (IC50 ). It was obtained a performance percentage of alkaloids of 0,2%. GC-MS showed a total of 9 identified alkaloids present in the bulb from Phaedranassa dubia being the most representative lycorine (54,10%), assoanine (13,77%), galanthamine (4,54%) and anhydrolycorine (3,71%); in turn 3 unidentified alkaloids (m/z 264, m/z 280, m/z 285) were found. The extract of alkaloids from Phaedranassa dubia showed inhibitory activity of AChE expressed as IC50 of 24,48 ± 0,39 µg/mL, with respect to the reference compound galanthamine whose result was 0,30 ± 0,01 µg/mL. As regards the inhibitory activity of BuChE presented an IC50 of 114,96 ± 4,94 µg/mL, being the value of galanthamine 4,41 ± 0,24 µg/mL. For both cholinesterases inhibitory activity results not exceed reference galanthamine compound and there is evidence of greater affinity of the extract of alkaloids to AChE. It is Recommended phytochemical and pharmacological studies more deep from Phaedranasa dubia of Ecuador, research on this species are scarce.