Abstract
We examined the protective effects of water-soluble derivatives of flavonoids,glucosyl hesperidin (G-HSP) and glucosyl rutin (G-Rutin), against DNA double-strand breaks induced by photo- and gamma-irradiation using a single-molecule observation. For photo-irradiation, we performed a real-time observation of double-strand breakage of individual DNA molecules stained with a fluorescent cyanine dye, YOYO-1, under focused illumination in solution by fluorescence microscopy, where YOYO-1 acts as a photocleavage agent by generating reactive oxygen species. To evaluate damage induced by gamma-ray irradiation, the length of DNA was measured after irradiation (0–650 Gy). The results indicate that G-HSP and G-Rutin protect against double-strand breaks caused by both photo- and gamma-ray irradiation. With regard to photo-induced double-strand breakage, G-Rutin provides twice as much protection as G-HSP. In contrast, the protective effect of G-Rutin against gamma-ray irradiation is almost the same as that of G-HSP. We concluded that the antioxidant potential of these compounds vary according the source of irradiation.
