Amentoflavone Protects against Hydroxyl Radical-induced DNA Damage via Antioxidant Mechanism

Objective: Oxidative DNA damage is involved in mutation, cell death, carcinogenesis, and aging. Since biflavonoid amentoflavone exhibited beneficial effects on DNA, we therefore investigated its protection against •OH-induced DNA oxidative damage then discussed the mechanism. It will enhance the understanding of interaction between biflavonoid vs DNA mediated by free radicals. Methods: The protective effect of amentoflavone against •OH-induced DNA damage was measured using our method. To explore the mechanism, it was further determined by •OH-induced bases damage, deoxyribose damage, and various antioxidant assays. Results: Amentoflavone increased dose-dependently its protective percentages against •OHinduced damage on DNA, bases, and deoxyribose; The IC50 were 31.85±4.75, 198.75±33.53, 147.14±20.95, 75.15±10.52, 93.75±16.36, 167.69±13.90, and 137.95±19.86 μM, respectively for DNA, cytosine, uracil, adenine, thymine, guanine, and deoxyribose damages. Radical-scavenging assays suggested that amentoflavone could effectively scavenge •O2 -, DPPH•, ABTS•+ radicals (IC50 values were respectively 8.98±0.23, 432.25±84.05, 7.25±0.35 μM). Conclusions: Based on the mechanistic analysis, it is concluded that amentoflavone can effectively protect against •OH-induced oxidative damage DNA (including base & deoxyribose moieties), via deoxynucleotide radical repairing, and reactive oxygen species (ROS) scavenging approaches which may be mediated by donating hydrogen atom (H•) and electron (e). Further analysis indicated that both scavenging and repairing approaches can be primarily attributed to its antioxidant mechanism which may ultimately arise from to the stability of its oxidized product semi-quinone form. Its protection against DNA damage may be generally responsible for the radioprotective and anti-inflammation effects.