Anti-choline esterase activity of ceramides from the Red Sea marine sponge Mycale euplectellioides

The isolation and structure elucidation of new phytoceramides from a methanolic extract of the Red Sea sponge Mycale euplectellioides was exclusively studied. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The anti-choline esterase activity of the isolated ceramides was evaluated in vitro using a microplate-based Ellman's assay. Bioassay guided isolation led to the isolation of a MEC-1 phytoceramide molecular species; further purification of MEC-1 afforded three pure phytoceramides: MEC-1-4, MEC-1-7 and MEC-1-8. Molecular modeling studies using glide docking showed tight binding of the ceramides to acetylcholine esterase (AChE). The ceramides showed a better docking score and glide Emodel value when compared to known AChE inhibitors. The ceramides interacted with an aromatic residue of the peripheral anionic site and penetrated deeply into the catalytic triad residues of the active site. Overall, the ceramides obtained using the approaches described here could be considered as promising lead compounds for the discovery and design of potent anti-choline esterase drug candidates, which would be used for Alzheimer's eradication.