Design, synthesis and biological activity of 8-hydroxy modified urolithin A derivatives as phosphodiesterase type II (PDE2) inhibitors

Urolithin A (UA) is a naturally occurring polyphenolic compound.Due to its remarkable efficacy in safeguarding the central nervous system, UA has emerged as a promising candidate for drug development targeting neurodegenerative diseases such as Alzheimer’s. However, the source of UA is limited and the activity of UA to inhibit PDE2 needs to be further improved. Therefore, this study will be optimized on the basis of UA to seek PDE2 inhibitors with better activity. In this study, we designed a series of UA derivatives based on 4HTX as the target protein and UA as the lead compound, utilizing the binding crystal structures of 4HTX and BAY60-7550 as references. After thorough screening, we successfully identified the 8-hydroxyl group as the precise site of modification. Utilizing 2-bromo-5-hydroxybenzoic acid as our primary raw material, we synthesized a series of the 8-hydroxyl modified UA. Subsequently, we evaluated the inhibitory activity of these synthesized UA derivatives using a phosphodiesterase assay kit. Ultimately, we screened a total of 34 derivatives; among them, compounds 1f, 1q, 2d, and 2j exhibited significant inhibitory activity against PDE2 with half-maximal inhibitory concentrations of 3.05 μM,0.67 μM, 0.57 μM, and 4.96 μM, respectively.