Acetylcholinesterase inhibition exerted by the extract of Daldinia eschscholtzii, a marine fungus associated with the coral Siderastrea siderea: GC-MS analysis and molecular docking of identified compounds

Background: Alzheimer's disease is a neurodegenerative disease that has no cure. The drugs used to treat Alzheimer's disease are based on the inhibition of the enzyme acetylcholinesterase (AChE). In this sense, marine fungal metabolites represent an alternative source for the discovery of drugs based on AChE inhibition (IAChE). The present research carried out a bioprospecting study of marine fungi with acetylcholinesterase inhibition potential. Results: A total of 17 marine fungi were isolated from three stony corals from the Veracruz Reef System. The fungal genera identified were Geotrichum, Curvularia, Penicillium, Aspergillus, and Daldinia. The IAChE was evaluated from the broth and biomass extracts of each fungal strain. As a result, Daldinia eschscholtzii was one of the three fungi with the greatest IAChE effect (32.7%). Subsequently, a bio-directed chromatographic purification of the methanolic extract of the biomass of D. eschscholtzii was carried out. The FRL8.1 fraction was the most active with an IAChE of 41.0%, a value close to Galantamine positive control (44.0%). Furthermore, compound analysis was carried out by GC-MS. Finally, it was determined that the metabolites responsible for the inhibitory effect are probably 4,7-dihydroxycoumarin and 5-nitro-2-naphthalenamine, which was demonstrated by their interactions with the AChE enzyme receptor through molecular docking studies. Conclusions: Coral-associated marine fungi produce secondary metabolites that inhibit acetylcholinesterase. This is the first report of D. eschscholtzii isolated from the stony coral Siderastrea siderea. Finally, we consider that more studies are needed to demonstrate the IAChE potential of marine fungi associated with corals or other marine organisms. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of Pontificia Universidad Catolica de Valparaiso. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).