Water and methanolic extracts of Ecklonia cava, a marine brown alga, were prepared by ultrasonic extraction (UE) and conventional extraction (CE) methods. The radical-scavenging activity and the inhibitory effects against hydrogen peroxide (H 2 O 2 )-induced DNA damage of the extracts were investigated. All extracts prepared by CE exhibited higher total polyphenolic content than that in the extracts prepared by UE. Extraction yield and total phenolic content increased as the UE time increased. The radical-scavenging activities increased as the UE time increased. All extracts prepared by CE exhibited higher 1,1-diphenyl-2-pricrylhydrazyl (DPPH) and hydroxyl radical-scavenging activities than did those prepared by UE. Extracts prepared by UE showed stronger scavenging activities on alkyl radical and H 2 O 2 than those prepared by CE did. Methanolic extract with UE 12 h (100MEU-12h) and methanolic extract with CE 24 h (100MEC-24h) were selected and evaluated by comet assay for their inhibitory effect against H 2 O 2 -induced DNA damage. 100MEU-12h showed slightly greater protective effect against H 2 O 2 -induced DNA damage than 100MEC-24h. Thus, UE can be effectively used as a seaweed extraction technique, and there is potential for scale-up of the extraction process.

Hyperglycemia-induced oxidative stress accelerates endothelial cell dysfunctions, which cause various complications of diabetes. The protective effects of 6,6'-bieckol (BEK), one of phlorotannin compound purified from Ecklonia cava against high-glucose-induced oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs), which is susceptible to oxidative stress. High glucose (30 mM) treatment induced HUVECs' cell death, but BEK, at concentration 10 or 50 μg/ml, significantly inhibited the high-glucose-induced cytotoxicity. Furthermore, treatment with BEK dose-dependently decreased thiobarbituric acid reactive substances (TBARS), intracellular reactive oxygen species (ROS) generation, and nitric oxide level increased by high glucose. In addition, high glucose levels induced the overexpressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor-kappa B (NF-κB) proteins in HUVECs, but BEK treatment reduced the overexpressions of these proteins. These findings indicate that BEK is a potential therapeutic agent that will prevent diabetic endothelial dysfunction and related complications.

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Oxidative stress mediates the cell damage in several neurodegenerative diseases, some of which are Alzheimer's disease (AD), multiple sclerosis and Parkinson's disease (PD). In this study, we investigated whether the taurine-rich cuttlefish extract could exert a protective effect on damaged human neuroblastoma SH-SY5Y cells induced by hydrogen peroxide (HO). Our results revealed that pre-treatment with cuttlefish extract effectively increased the cell viability by protecting the cells from intracellular reactive oxygen species (ROS) induced by HO exposure. Furthermore, apoptosis related proteins Bcl-2 and Bax were investigated by western-blot analysis and results indicated that cuttlefish extract promoted the expression of anti-apoptotic Bcl-2 protein while inhibiting the expression of pro-apoptotic Bax protein. Therefore, cuttlefish extract containing the ability of scavenging excessive ROS, the capacity of anti-oxidative stress, could be employed in neurodegenerative disease prevention. In conclusion, the results suggest that cuttlefish extract could be used as a potential candidate for preventing several human neurodegenerative and other disorders caused by oxidative stress.

Red ginseng marc (RGM) is generally discarded as waste, even though it contains bioactive components. Hence, this study aimed to evaluate the bioactive components and properties of RGM extracts prepared via the fermentation of Bacillus subtilis (BSRGM) and Saccharomyces cerevisiae (SCRGM). Polyphenols were not detected in non-fermented RGM (NRGM) extracts, whereas the polyphenol levels in RGM extracts significantly increased with fermentation. The BSRGM and SCRGM extracts showed significantly higher free radicals scavenging activity than those of NRGM extracts. Treatment with the fermented RGM extracts also increased IgA levels compared to that of NRGM extracts, whereas it decreased IgE production by the mesenteric lymph node, spleen, and Peyer's patch lymphocytes. These results suggest that fermented RGM extracts may ameliorate inflammation. In addition, the phenolic compounds in fermented RGM extracts may have biological activity, making fermented RGM extracts a potential natural resource that could be used in the functional foods industry.