| Dietary flavonoids are ubiquitous and are marketed as supplements. Characterized as antioxidants, they offer protection against a number of degenerative diseases. Flavonoid mechanics involve free radical scavenging, metal chelation, and substrate association. The skeletal structure of flavonoids is a fused ring system modified by hydroxyl, sugar, and carbohydrate additions. Flavone is a structurally simple flavonoid. Quercetin and its glycosidic analog rutin are complex structures. Using a DNA oxidation/cleavage assay, flavone reduces DNA nicking by 91%. Depending on the solvent system used, quercetin can either increase or decrease DNA oxidation. Rutin exhibits neither pro- nor antioxidant activity. The molecular interactions responsible for these results are defined for flavone. (1) Flavone intercalates into DNA and saturates DNA at a 1/3.5 flavone:DNA molar ratio. (2) Flavone reduces iron-dependent DNA oxidation. (3) Flavone interacts with quercetin to enhance DNA protection. These results characterize the primary activities of a simple flavonoid. |
