Alkaloid profile and cholinesterase inhibition activity of five species of Amaryllidaceae family collected from Merida state-Venezuela

The Amaryllidaceae family is distributed mainly in tropical and subtropical areas but also in temperate zones. In Venezuela, there are 6 genera and 13 species distributed around the country. This family is characterized by its ability to biosynthesize alkaloids with an isoquinoline type structure. In addition, a number of investigations have revealed a variety of biological activities for these alkaloids, such as antimalarial, antitumoral, analgesic, antimicrobial, cytotoxic, acetylcholinesterase inhibitory activity, among others. Galanthamine, an alkaloid first obtained from Galanthus woronowii, has been used since 2001 for the palliative therapy of mild-moderate Alzheimer's disease. Therefore, there is great interest on searching for galanthamine sources among the wide range of Amaryllidaceae species distributed around the world. The present investigation, carried out with five species from the Amaryllidaceae family, Crinum amabile, Crinum erubescens, Crinum moorei, Amaryllis belladonna and Zephyranthes carinata, collected from different locations in Merida State-Venezuela and analyzed by GC-MS, showed the alkaloid profile of leaves and bulbs of these species. Results revealed that lycorine and related compounds, such as 11,12-dehydro-anhydrolycorine and 1-O-acetyllycorine, were present in almost all samples analyzed, with lycorine predominant. The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition capacity of these alkaloid extracts showed a strong to moderate inhibitory effect on both enzymes; C. amabile leaves being the extract with the strongest inhibitory activity against AChE at 0.88 mu g/mL as well as BuChE at 4.46 mu g/mL, followed by Crinum erubescens leaves with values of 1.75 mu g/mL and 8.72 mu g/mL, respectively, compared to the values observed for galanthamine used as control. Present investigation constitutes the first in silico report about buphanisine interactions with AChE and BuChE active sites. (C) 2020 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

The Amaryllidaceae family is widely distributed and contains 13 species in Venezuela. These plants are capable of synthesizing various alkaloids with diverse biological activities, with lycorine being a predominant component. Extracts from these plants show inhibitory effects on AChE and BuChE.