Design, Synthesis and Evaluation of 8-Thiosubstituted 1,3,7-Trimethylxanthine Hydrazones with In-vitro Neuroprotective and MAO-B Inhibitory Activities

Objective: The syntheses and biological activities of 8-thiosubstituted-1,3,7- trimethylxanthine derivatives bearing an aromatic hydrazide-hydrazone fragment in the side chain at C8 are described. Methods: The chemical structures of the synthesized compounds 6a-m were confirmed based on their MS, FTIR, 1H NMR and 13C NMR analyses. Results: The in vitro investigations of neuroprotective effects manifested on cellular (human neuroblastoma cell line SH-SY5Y) and sub-cellular (isolated rat brain synaptosomes) levels show that compounds 6g and 6i demonstrate statistically significant activity. The performed monoamine oxidase B (MAO-B) inhibition study in vitro show that compounds 6g and 6i possess a significant MAO-B inhibition activity close to L-deprenyl. Conclusion: These results suggest that such compounds may be utilized for the development of new candidate MAO-B inhibitors for the treatment of Parkinson’s disease.