The seaweed Ecklonia cava, a brown algae abundant in JeJu Island, South Korea, has large amounts of the polyphenol compound phloroglucinol (PG, 1,3,5-trihydroxybenzene), which has been proposed to exert interesting biological properties including antioxidant and radioprotective effects against ionizing radiation-induced damages in various cells and tissues. To identify antioxidant and radioprotective effects of PG in skin tissues, we exposed mice to 8.5 Gy whole body irradiation (WBI) at day 6 after depilation with and without PG treatment. In PG treated cases, PG was applied twice, once at 17.8 hours before and then at the time of WBI. At 8 hours after WBI, a reduction in the formation of thiobarbituric acid-reactive substrates (TBARS) was observed in the PG treated group. Upon western blot analysis, PG treatment overexpressed the MnSOD, catalase, and GPx-1, although the difference was not significant. In parallel with the results of western blot analysis, the percentage of MnSOD-and catalase-positive cells was significantly increased at 8 and 24 hours after WBI, while no significant difference was observed over 48 hours in PG treated skins. Moreover, PG treatment increased the percentage of Ki-67 positive cells compared with that of irradiated only mice at 8 hours after WBI. Our results suggest that PG is effective at attenuating oxidative stress, and that the promotion of antioxidant enzymes such as MnSOD and catalase may be an important aspect for its radioprotection in skin.

Sasa quelpaertensis Nakai is a type of edible bamboo grass distributed on Jeju Island, Korea. S. quelpaertensis has been used as afolk medicine for treatment of a variety of ailments. It has been reported to present biological effects, including anti-inflammatory and antioxidant effects. In this study, we demonstrate that S. quelpaertensis Nakai extract (SNE) rescues immunocytes from gamma radiation-induced apoptosis and oxidative DNA damage. We examined the cytotoxicity, cell proliferation, DNA damage, apoptosis, and generation of reactive oxygen species (ROS) in mice given SNE for 45 days in immune cells. To determine the splenocytes protection capability of SNE, gamma-ray was irradiated to the whole body of C57BL/6 mice. Our results suggest that SNE stimulated the proliferation of splenocytes without cytotoxic effects. In addition, SNE not only decreased DNA damage but also reduced apoptosis of splenocytes, and attenuated the production of ROS generation in hydrogen peroxide-induced splenocytes. Therefore, SNE can protect against gamma radiation-induced damage in mice.