ABSTRACT The fruit of the Prunus mume (Siebold) Siebold & Zucc., Rosaceae (Korean name: Maesil) has long been used as a health food or valuable medicinal material in traditional herb medicine in Southeast Asian countries. In this study, we determined the potential therapeutic efficacy of the ethanol extract of P. mume fruits (EEPM) against H2O2-induced oxidative stress and apoptosis in the murine skeletal muscle myoblast cell line C2C12, and sought to understand the associated molecular mechanisms. The results indicated that exposure of C2C12 cells to H2O2 caused a reduction in cell viability by increasing the generation of intracellular reactive oxygen species and by disrupting mitochondrial membrane permeability, leading to DNA damage and apoptosis. However, pretreatment of the cells with EEPM before H2O2 exposure effectively attenuated these changes, suggesting that EEPM prevented H2O2-induced mitochondria-dependent apoptosis. Furthermore, the increased ex-pression and phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2) and up-regulation of heme oxygenase-1 (HO-1), a phase II antioxidant enzyme, were detected in EEPM-treated C2C12 cells. We also found that zinc protoporphyrin IX, an HO-1 inhibitor, attenuated the protective effects of EEPM against H2O2-induced reactive oxygen species accumulation and cytotoxicity. Therefore, these results indicate that the activation of the Nrf2/HO-1 pathway might be involved in the protection of EEPM against H2O2-induced cellular oxidative damage. In conclusion, these results show that EEPM contributes to the prevention of oxidative damage and could be used as a nutritional agent for oxidative stress-related diseases.

AbstractFucoidan, a sulfated polysaccharide found in marine algae and brown seaweeds, has been shown to inhibit the in vitro growth of human cancer cells. This study was conducted in cultured human bladder cancer EJ cells to elucidate the possible mechanisms by which fucoidan exerts its anti-proliferative activity, which until now has remained poorly understood. Fucoidan treatment of EJ cells resulted in dose-dependent inhibition of cell growth and induced apoptotic cell death. Flow cytometric analysis revealed that fucoidan led to G1 arrest in cell cycle progression. It was associated with down-regulation of cyclin D1, cyclin E, and cyclin-dependent-kinases (Cdks) in a concentration-dependent manner, without any change in Cdk inhibitors, such as p21 and p27. Furthermore, dephosphorylation of retinoblastoma protein (pRB) by this compound was associated with enhanced binding of pRB with the transcription factors E2F-1 and E2F-4. Overall, our results demonstrate that fucoidan possesses anticancer activity potential against bladder cancer cells by inhibiting pRB phosphorylation.

In this study, the practical usefulness and fundamental applicability of a self-potential (SP) method for identifying the hydraulically-active fractures were evaluated by a comparison of SP methods with other geophysical logging methods and hydraulic tests. Potentially permeable fractures intersecting a shallow, 10-m borehole were first identified using conventional geophysical methods such as acoustic borehole televiewer imaging and temperature, electrical conductivity and gamma-gamma logs. These results were then compared to results of analysis using the SP method. Constant pressure injection and recovery tests were conducted for verification of the hydraulic properties of the fractures identified by various logging methods. The acoustic borehole televiewer and gamma-gamma logs detected the openings or weathering zones associated with fractures intersecting the borehole, but they could not prove that groundwater was flowing through the detected fractures. The temperature and fluid-column electrical conductivity logs were unable to detect the fractured zones where groundwater in the borehole flows out to the surrounding rock aquifers. Comparison of results from the different methods tested showed that the most effective correlation between logs and the distribution of hydraulic conductivity was given by the SP signals, and that SP logging can accurately indicate the location of hydraulically-active permeable fractures. Based on these results, the SP method is recommended for determining the location of hydraulically-active fractures rather than other conventional geophysical logs. This self-potential method can be effectively applied in the initial stage of a site investigation to select the optimal site location or to evaluate the hydrogeological properties of fractures in underground exploration studies, such as those related geothermal reservoir evaluation and radioactive waste disposal.