Sulfonamides and Sulphonyl Ester of Quinolines as Non-Acidic, Non- Steroidal, Anti-inflammatory Agents

Background: Quinolines are an important class of heterocyclic compounds possessing a wide range of biological activities. Previously, we had identified Schiff bases of quinoline as potential anti-inflammatory agents, thus the current work is the continuation of our previous study. Objective: In the current study, 3-, 5-, and 8-sulfonamide and 8-sulfonate derivatives of quinoline (1-50) were synthesized and their anti-inflammatory potential was evaluated. These synthetic analogs were evaluated for their anti-inflammatory activity via ROS (Reactive oxygen species) inhibitory effect produced from phagocytes from human whole blood. Methods: The sulfonamide and sulfonate derivatives of quinoline were synthesized via treating 5-, 3-, 8-amino, and 8-hydroxy quinolines with different substituted sulfonyl chlorides in pyridine. The synthetic molecules were characterized using various spectroscopic techniques and screened for their anti-inflammatory potential. Results: Among the synthetic derivatives 1-50, six compounds showed good to moderate antiinflammatory activity. Compounds 47 (IC50 = 2.9 ± 0.5 μg/mL), 36 (IC50 = 3.2 ± 0.2 μg/mL), and 24 (IC50 = 6.7 ± 0.3 μg/mL) exhibited enhanced activity as compared to the standard ibuprofen (IC50 = 11.2 ± 1.9 μg/mL). Compounds 20 (IC50 = 25.5 ± 0.7 μg/mL), 50 (IC50 = 42.9 ± 5.6 μg/mL), and 8 (IC50 = 53.9 ± 3.1 μg/mL) were moderately active, however, rest of the compounds were found to be inactive. Conclusion: The sulfonamide and sulfonate derivatives of quinoline were found to have promising anti-inflammatory activity. Further studies on the modification of these molecules may lead to the discovery of new and potential anti-inflammatory agents.