# Alkaloid Profiling and Anti-Cholinesterase Potential of Three Different Genera of Amaryllidaceae Collected in Ecuador: Urceolina Rchb., Clinanthus Herb. and Stenomesson Herb

## TL;DR

This study explores the chemical and anti-Alzheimer's potential of Ecuadorian Amaryllidaceae plants, identifying new alkaloids and their enzyme-inhibiting properties.

## Contribution

The study identifies novel alkaloids and evaluates the anti-cholinesterase activity of understudied Amaryllidaceae species from Ecuador.

## Key findings

- Twenty-six alkaloids were identified in four Ecuadorian Amaryllidoideae species using GC-MS.
- C. incarnatus and U. formosa showed strong AChE inhibition with IC50 values of 1.73 and 30.56 µg·mL−1, respectively.
- Molecular dynamics showed that 2-hydroxyanhydrolycorine interacts with AChE similarly to galanthamine.

## Abstract

Ecuador is an important center of biodiversity for the plant subfamily Amaryllidoideae, known for its important bioactive molecules. This study aimed to assess the chemical and biological potential of four different Amaryllidoideae species collected in Ecuador: Urceolina formosa, Urceolina ruthiana, Clinanthus incarnatus, and Stenomesson aurantiacum. Twenty-six alkaloids were identified in the bulb extracts of these species using GC-MS. The extract of S. aurantiacum exhibited the greatest structural diversity and contained the highest amounts of alkaloids, particularly lycorine and galanthamine. Only for this species, identification of all the alkaloids belonging to this chemical profile was not possible. Six of them remain unidentified. The potential of these three Amaryllidoideae genera against Alzheimer’s disease was then evaluated by measuring their AChE and BuChE inhibitory activity, revealing that C. incarnatus and U. formosa (from Sucumbíos province) showed the best results with IC50 values of 1.73 ± 0.25 and 30.56 ± 1.56 µg·mL−1, respectively. Molecular dynamic assays were conducted to characterize the possible interactions that occurs among 2-hydroxyanhydrolycorine and the AChE enzyme, concluded that it is stabilized in the pocket in a similar way to galanthamine. This study expands our understanding of the biodiversity of Amaryllidoideae species from Ecuador, highlighting their potential as source of chemical compounds with pharmaceutical applications.