Synthesis and Biological Assay of Hybrids Between Epinastine and Salicylic Acid as Promising Nitric Oxide Production Inhibitors: Synthesis and Nitric Oxide Inhibitory Activity of Epinastine-Salicylic Acid Hybrids

The first synthesis of novel hybrid compounds 3-6 from epinastine (1) and salicylic acid (2) has been achieved via amide bond using molecular hybridization approach and their in vitro inhibitory activity towards nitric oxide (NO) formation in lipopolysaccharide (LPS) induced RAW 264.7 macrophages as a sign of anti-inflammatory activity has been evaluated. All the hybrid compounds synthesized 3-6 displayed better inhibitory effect against NO production than individual compounds, 1 and 2. Especially, directly conjugated hybrid compound 3 displayed concentration-dependent strong inhibition of NO production with an IC50 value of 12.78 mu M, which was significantly lower than the parent compounds 1 (IC50 > 100 mu M) and 2 (IC50 > 100 mu M). These preliminary results indicate that further studies are needed to be carried out to demonstrate the mechanism by which compound 3 exerts its inhibitory activity.