Joshi P C
Toxicol Lett. 1985 Aug;26(2-3):211-7. doi: 10.1016/0378-4274(85)90169-9.
Riboflavin was found to generate singlet oxygen (1O2) and superoxide anion radicals O2-. on exposure to UV-A (320-400 nm) and UV-B (290-320 nm) light. Studies with deoxyguanosine (dGuo) showed that 1O2 was largely responsible for riboflavin-sensitised photodegradation of the guanine base of DNA and RNA. Azide ions (N-3) and 1,4 diazabicyclo-[2.2.2]-octane (DABCO) produced over 90% inhibition of dGuo photo oxidation, whereas superoxide dismutase did not show any noticeable quenching effect under similar conditions. Photo oxidation of dGuo by riboflavin and UV radiation is of significant importance from the point of view of cell-damaging reactions by activated oxygen species produced by the synergistic action of sunlight and chemical agents. It is now known that activated oxygen species are responsible for skin photosensitisation, tumor promotion and carcinogenic properties.
研究发现，核黄素在暴露于紫外线A（320 - 400纳米）和紫外线B（290 - 320纳米）光时会产生单线态氧（1O2）和超氧阴离子自由基O2-。对脱氧鸟苷（dGuo）的研究表明，1O2在很大程度上导致了核黄素敏化的DNA和RNA鸟嘌呤碱基的光降解。叠氮离子（N-3）和1,4 - 二氮杂双环-[2.2.2]-辛烷（DABCO）对dGuo光氧化的抑制率超过90%，而在类似条件下超氧化物歧化酶未表现出任何明显的猝灭作用。从阳光和化学试剂协同作用产生的活性氧物种引起细胞损伤反应的角度来看，核黄素和紫外线辐射对dGuo的光氧化具有重要意义。现在已知活性氧物种与皮肤光敏化、肿瘤促进和致癌特性有关。
