Synthesis, anti-inflammatory and antioxidant activity of ring-A-monosubstituted chalcone derivatives

Abstract

A library of ring-A-monosubstituted chalcone derivatives (4a–4i, 5a and 5b) was designed and synthesised. The structures as well as the identities of these compounds were established on the basis of spectral (1H NMR, 13C NMR, FT-IR and Mass) and elemental (C, H, N) analyses. All the derivatives were evaluated for their anti-inflammatory and antioxidant activities in vitro using the inhibition of protein denaturation and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays, respectively. The results indicated a promising anti-inflammatory activity for most of the synthesised compounds with many derivatives showing activities similar to or greater than that of the standard. The sulphonamide-substituted chalcones 4h, 4i, 5a and 5b were found to be the most active derivatives across the concentration range tested. However, all the derivatives exhibited rather mild antioxidant activity compared to the ascorbic acid standard. Interestingly, it was observed that the unsubstituted parent chalcone was one of the optimal compounds with only the trifluoromethyl analogue 4a showing better activity as an antioxidant. The two regioisomeric aminochalcones and 4′-cyanochalcone 4b also seemed to possess decent antioxidant potential.