Flurbiprofen Derivatives as Potential DPPH and ABTS Radical Scavengers

Flurbiprofen derivatives 1–18 were screened for their free radical scavenging activities. Initially, flurbiprofen hydrazide 1 was synthesized and subjected to various chemical transformations to obtain a range of flurbiprofen hydrazide analogs 2–9 and flurbiprofen–oxadiazole analogs 10–18. All compounds 1–18 showed good DPPH (IC50 = 0.60±0.16 to 1.77±0.04 µM) and ABTS (IC50 = 0.40±0.10 to 1.46±0.06 µM) radical scavenging activities as compared to the standard ascorbic acid (IC50 = 0.51±0.18 µM for both DPPH and ABTS). Among the synthesized derivatives, compound 13 (DPPH, IC50 = 0.40±0.10 µM; ABTS, IC50 = 0.60±0.16 µM) was found to be the most active. The remaining compounds displayed good to moderate radical scavenging activities. These active compounds can serve as lead molecules to identify more powerful antioxidant agents.