Anti-Inflammatory Activities of 8-Benzylaminoxanthines Showing High Adenosine A(2A) and Dual A(1)/A(2A) Receptor Affinity

Chronic inflammation plays an important role in the development of neurodegenerative diseases, such as Parkinson’s disease (PD). In the present study, we synthesized 25 novel xanthine derivatives with variable substituents at the N1-, N3- and C8-position as adenosine receptor antagonists with potential anti-inflammatory activity. The compounds were investigated in radioligand binding studies at all four human adenosine receptor subtypes, A(1), A(2A), A(2B) and A(3). Compounds showing nanomolar A(2A) and dual A(1)/A(2A) affinities were obtained. Three compounds, 19, 22 and 24, were selected for further studies. Docking and molecular dynamics simulation studies indicated binding poses and interactions within the orthosteric site of adenosine A(1) and A(2A) receptors. In vitro studies confirmed the high metabolic stability of the compounds, and the absence of toxicity at concentrations of up to 12.5 µM in various cell lines (SH-SY5Y, HepG2 and BV2). Compounds 19 and 22 showed anti-inflammatory activity in vitro. In vivo studies in mice investigating carrageenan- and formalin-induced inflammation identified compound 24 as the most potent anti-inflammatory derivative. Future studies are warranted to further optimize the compounds and to explore their therapeutic potential in neurodegenerative diseases.