Position Matters: Effect of Nitro Group in Chalcones on Biological Activities and Correlation via Molecular Docking

A series of nine nitro group-containing chalcones were synthesized to investigate their anti-inflammatory and vasorelaxant activities via in vivo, ex vivo, and in silico studies. The anti-inflammatory effects of the compounds were evaluated via a TPA-induced mouse ear edema model, and the vasorelaxant effects were evaluated via an isolated organ model in addition to molecular docking studies. The compounds with the highest anti-inflammatory activity were 2 (71.17 ± 1.66%), 5 (80.77 ± 2.82%), and 9 (61.08 ± 2.06%), where the nitro group is located at the ortho position in both rings, as confirmed by molecular docking with COX-1 and COX-2. The compounds with the highest vasorelaxant activity were 1 (81.16 ± 7.55%), lacking a nitro group, and 7 (81.94 ± 2.50%), where the nitro group is in the para position of the B ring; both of these compounds interact with the eNOS enzyme during molecular docking. These results indicate that the position of the nitro group in the chalcone plays an important role in these anti-inflammatory and vasorelaxant activities.