Playing Around the Coumarin Core in the Discovery of Multimodal Compounds Directed at Alzheimer's-Related Targets: A Recent Literature Overview.

Alzheimer's disease (AD) causes a great socioeconomic burden because of its increasing prevalence and the lack of effective therapies. The multifactorial nature of AD prompts researchers to search for new strategies for discovering disease-modifying therapeutics. To this extent, the multitarget approach holds the potential of synergic or cooperative activities arising from compounds that are properly designed to address two or more pathogenetic mechanisms. As a privileged and nature-friendly scaffold, coumarin has successfully been enrolled as the heterocyclic core in the design of multipotent anti-Alzheimer's agents. Herein, we comprehensively summarize the most recent literature (2018-2023), covering the rational design and the discovery of coumarin-containing multitarget directed ligands (MTDLs) whose anti-AD profile encompassed at least two different biological activities relevant for disease onset and progression. To enhance the clarity of presentation, synthetic coumarin-based MTDLs are categorized into four clusters based on their substitution pattern and reported bioactivities: (i) mono-, (ii) di-, and (iii) polysubstituted coumarins directed at protein targets, and (iv) coumarins directed at protein targets with additional metal-chelating features. Before discussing multimodal coumarins, the rationale for addressing each biological target is briefly presented.