Synthesis and Activity Evaluation of Vinpocetine-Derived Indole Alkaloids

This study focuses on the synthesis of novel vinpocetine derivatives (2-25) and their biological evaluation. The chemical structures of the synthesized compounds were fully characterized using techniques such as 1H NMR, 13C NMR, and HRMS. The inhibitory activity of the synthesized compounds on PDE1A was evaluated, and the results revealed that compounds 3, 4, 5, 12, 14, 21, and 25 exhibited superior inhibitory activity compared to vinpocetine. Compound 4, with a para-methylphenyl substitution, showed a 5-fold improvement in inhibitory activity with an IC50 value of 3.53 +/- 0.25 mu M. Additionally, compound 25, with 3-chlorothiazole substitution, displayed an 8-fold increase in inhibitory activity compared to vinpocetine (IC50 = 2.08 +/- 0.16 mu M). Molecular docking studies were conducted to understand the binding models of compounds 4 and 25 within the active site of PDE1A. The molecular docking study revealed additional binding interactions, such as pi-pi stacking and hydrogen bonding, contributing to the enhanced inhibitory activity and stability of the ligand-protein complexes. Overall, the synthesized vinpocetine derivatives demonstrated promising inhibitory activity on PDE1A, and the molecular docking studies provided insights into their binding modes, supporting further development of these compounds as potential candidates for drug research and development.