Antioxidant, molecular docking and computational investigation of new flavonoids

•A new series of bromo‑substituted flavonoids were synthesized and characterized by spectroscopic analysis.•The newly synthesized compounds were found good antioxidants.•All the compounds were recognized to be anti-inflammatory compounds by molecular docking study against Keap 1.•Structure activity relationship was studied using DFT approach. Flavonoids are a group of polyphenolic compounds diverse in structure, biological and pharmacological functions possessing antioxidant potential. New flavonoids (3a, 3b, 4a, 4b, 5a and 5b) were synthesized by acid catalysed condensation of bromo‑benzaldehydes and 2,5-dihydroxyacetophenone. In vitro antioxidant potential of synthesized compounds was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation (ABTS+) radical scavenging, iron chelating, iron reducing and phosphomolybdenum activity. The results revealed that DPPH radical scavenging and ABTS+scavenging activity of compounds 3a and 3b (chalcones) were better than reference compounds i.e., trolox and ascorbic acid. Furthermore, molecular docking was performed to check the affinity of flavonoids with Keap1 for the activation of antioxidant defense system of body and computational study was carried out by DFT approach using B3LYP functional and 6–31G** basis set. All the compounds showed better results compared to the reference compounds and molecular docking studies supported the computational results.