Acetylcholinesterase inhibitory activity from Amaryllis belladonna growing in Chile: enzymatic and molecular docking studies

Abstract

Alkaloid profiles from Amaryllis belladonna plants collected in Chile were examined by GC-MS to assess their inhibitory activity on acetylcholinesterase (AChE) using in vitro and in silico methodologies. The alkaloid extract was roughly separated by column chromatography on silica gel. AChE inhibitory activities from extracts and purified alkaloids were tested by the Ellman method and a molecular docking study was performed to assess the interaction between AChE and purified alkaloids. Sixteen alkaloids were found from hexane and chloroform extracts, and three were isolated and identified as buphanidrine, acetylcaranine and lycorine. Chloroform extract showed the greatest AChE inhibitory activity with IC₅₀ value 8.89 µg/mL, whereas buphanidrine exhibited the highest inhibitory activity, with IC₅₀ value 17.56 µg/mL. Inhibition kinetics showed that buphanidrine acts as a mixed inhibitor and molecular docking supports this inhibition mechanism. Overall, our study supports the potential use of A. belladonna as an alkaloid source with AChE inhibitory activity.

Keywords:

• Mixed inhibition
• buphanidrine
• medicinal plant
• peripheral anionic site (PAS)

Acknowledgments

The authors would like to acknowledge for the financing of the Universidad de La Frontera, , Project DIUFRO DI18-0017 and Laboratory of Química Ecológica, Universidad de La Frontera, Chile. We thank Dr. Herbert Venthur for his valuable comments to improve the quality of the manuscript.

Disclosure statement

The authors declare no conflict of interest.