Protective Effect Against Hydroxyl Radical-induced DNA Damage and Antioxidant Mechanism of [6]-gingerol: A Chemical Study

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against •OH -induced DNA damage ( IC₅₀ 328.60±24.41μM ). Antioxidant assays indicated that [6]-gingerol could efficiently scavenge various free radicals, including •OH radical ( IC₅₀ 70.39±1.23μM ), •O₂⁻ radical ( IC₅₀ 228.40±9.20μM ), DPPH• radical ( IC₅₀ 27.35±1.44μM ), and ABTS⁺• radical ( IC₅₀ 2.53±0.070μM ), and reduce Cu²⁺ ion ( IC₅₀ 11.97±0.68μM ). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and DPPH• radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 [M+Na ] ⁺ , and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against •OH -induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is •OH radical scavenging; (iii) [6]-gingerol scavenges •OH radical through hydrogen atom ( H• ) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.