Antioxidant Activity of Substituted Flavones: An Updated Study

This chapter compare the antioxidant activity of synthesized substituted flavones by various free radical scavenging assays. Flavonoids are a group of natural substances, found in fruits, vegetables, flowers, tea, wine, etc. They have a common phenylbenzopyrone structure and are broadly classified into flavones, flavanols, flavonols, flavanones, flavanonols and isoflavones.

The flavones used in the study, 6,3’,4’ – trihydroxy flavones (THF) and 3-hydroxy-6,3’-dimethoxy flavones (DMF) were synthesized using standard procedures and their antioxidant activity was compared by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, Hydrogen peroxide scavenging assay, Hydroxyl radical scavenging assay, Reducing power capacity, Superoxide free radical scavenging assay and 2,2’azinobis 3 ethyl benzothiazoline 6 sulfonic acid (ABTS) assay. Hydroxyl radical is one of the most potent reactive oxygen species in the biological system that reacts with polyunsaturated fatty acid moieties of cell membrane phospholipids and causes damage to cell.

In the DPPH assay THF has an IC50 value of 18.89µg/ml which was much better than that of standard ascorbic acid which was 26.1µg/ml. The THF had a much better antioxidant activity in most of the free radical scavenging assays. The compounds demonstrated considerable free radical scavenging activity and could be further evaluated for amelioration of free radical mediated diseases like inflammation, cancer, neurodegenerative disorders etc.