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Abstract: Enzymatic extraction has been successfully used for extracting numerous biologically active compounds from a wide variety of seaweeds. In this study, we found that enzymatic extraction of the fucoidan from Ecklonia cava may be more advantageous than water extraction. Therefore, we studied the E. cava fucoidans extracted by the enzymatic extraction technique and used ion-exchange chromatography to determine their molecular characteristics and anti-inflammatory activities. The crude and fractionated fucoidans (F 1, F 2, and F 3) consisted mostly of carbohydrates (47.1–57.1%), uronic acids (9.0–15.8%), and sulfates (16.5–39.1%), as well as varying levels of proteins (1.3–8.7%). The monosaccharide levels significantly differed, and the composition included fucose (53.1–77.9%) and galactose (10.1–32.8%), with a small amount of rhamnose (2.3–4.5%), xylose (4.0–8.2%), and glucose (0.8–2.2%). These fucoidans contained one or two subfractions with an average molecular weight (M w) ranging from 18 to 359×103 g/mol. These fucoidans significantly inhibited NO production in lipopolysaccharide (LPS)-induced Raw 264.7 macrophage cells by down-regulating the expression of iNOS, COX-2, and pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β. Thus, the present results suggest that E. cava fucoidan may be a potentially useful therapeutic approach for various inflammatory diseases. [Copyright &y& Elsevier]

Abstract: Recently, there has been a growing interest in alternative therapies of marine algae for diabetes. Therefore, the anti-diabetic effects of brown alga, Ecklonia cava was investigated in type 2 diabetic animal. Male C57BL/KsJ-db/db (db/db) mice were divided into control, dieckol rich extract of E. cava (AG-dieckol), or rosiglitazone (RG) groups. The blood glucose, blood glycosylated hemoglobin levels, and plasma insulin levels were significantly lower in the AG-dieckol and RG groups than in the control db/db mice group, while glucose tolerance was significantly improved in the AG-dieckol group. AG-dieckol markedly lowered plasma and hepatic lipids concentration compared to the control db/db mice group. The antioxidant enzyme activities were significantly higher in the AG-dieckol group than in the control db/db mice group, yet its TBARS level was markedly lower compared to the RG group. With regard to hepatic glucose regulating enzyme activities, glucokinase activity was enhanced in the AG-dieckol group mice, while glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities in the AG-dieckol group mice were significantly lowered than those in the control db/db mice group. These results suggest that AG-dieckol exert an anti-diabetic effect in type 2 diabetic mice by improving the glucose and lipid metabolism and antioxidant enzymes. [Copyright &y& Elsevier]

Abstract: Brown algae, Ecklonia cava has been regarded as a useful material in the prevention or treatment of several human diseases in Jeju Island, Korea. In this study, we investigated its antioxidant activity, and isolated a new antioxidative compound, which was identified as 2,7″-phloroglucinol-6,6′-bieckol (PHB) on the basis of LC/MS, as well as 1H and 13C NMR spectroscopy results. The antioxidant activity of PHB was evaluated via several in vitro assays, such as radical scavenging activities using electron spin resonance spectrometry, intracellular reactive oxygen species scavenging activity, and DNA damage assays. PHB evidenced profound scavenging activities on DPPH, alkyl, hydroxyl, and superoxide radicals (IC50: 0.51, 2.07, 75.64 and 57.19μM for DPPH, alkyl, hydroxyl and superoxide radicals, respectively). The antioxidant activity of PHB was higher than that of ascorbic acid. Furthermore, PHB effectively inhibited H2O2-induced DNA damage. The results of this study indicate that PHB may prove useful as a novel natural marine antioxidant. [Copyright &y& Elsevier]

Abstract: This study was designed to investigate whether dieckol may inhibit α-glucosidase and α-amylase activities, and alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice. Dieckol isolated from Ecklonia cava, brown algae, evidenced prominent inhibitory effect against α-glucosidase and α-amylase. The IC50 values of dieckol against α-glucosidase and α-amylase were 0.24 and 0.66mM, respectively, which evidenced the higher activities than that of acarbose. Dieckol did not exert any cytotoxic effect in human umbilical vein endothelial cells (HUVECs) at various concentrations (from 0.33 to 2.69mM). The increase of postprandial blood glucose levels were significantly suppressed in the dieckol administered group than those in the streptozotocin-induced diabetic or normal mice. Moreover, the area under curve (AUC) was significantly reduced via dieckol administration (259 versus 483mmolmin/l) in the diabetic mice as well as it delays absorption of dietary carbohydrates. Therefore, these result indicated that dieckol might be a potent inhibitor for α-glucosidase and α-amylase. [Copyright &y& Elsevier]

Abstract: The effect of dieckol, one of phlorotannin polyphenol compound purified from Ecklonia cava (E. cava) against high glucose-induced oxidative stress was investigated using human umbilical vein endothelial cells (HUVECs), which is susceptible to oxidative stress. High glucose (30mM) treatment induced HUVECs cell death, but dieckol, at concentration 10 or 50μg/ml, significantly inhibited the high glucose-induced cytotoxicity. Furthermore, treatment with dieckol 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-kB) proteins in HUVECs, but dieckol treatment reduced the overexpressions of these proteins. These findings indicate that dieckol is a potential therapeutic agent that will reduce the damage caused by hyperglycemia-induced oxidative stress associated with diabetes. [Copyright &y& Elsevier]

Abstract: In the present study, the attenuation of type ІІ diabetes by dieckol, a phlorotannin derivative isolated from brown seaweed, Ecklonia cava was investigated in C57BL/KsJ-db/db, a type ІІ diabetes mouse model. Dieckol was administered intraperitoneal injection at doses of 10 and 20mg/kg body weight diabetes mice for 14days. The blood glucose level, serum insulin level and body weight were significantly reduced in the dieckol administered group, compared to that of the saline administered group. Furthermore, reduced thiobarbituric acid reactive substraces (TBARS), as well as increased activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-px) in liver tissues were observed in the dieckol administered group. In addition, increased levels of the phosphorylation of AMPK and Akt were observed in the muscle tissues of the dieckol administered group in a Western blotting analysis. According to the findings of this study, it could be suggested that, dieckol can be developed as a therapeutic agent for type ІІ diabetes. [Copyright &y& Elsevier]

Abstract: Algal fucoidan is a marine sulfated polysaccharide that evidences a variety of biological activities. We assessed the potential activity of the sulfated polysaccharide from Ecklonia cava, on anti-inflammatory activity in LPS-stimulated RAW 264.7 cells. In this study, E. cava was hydrolyzed by five carbohydrases and five proteases. Our findings demonstrated that the AMG extract has the highest yield and exerts the most profound inhibitory effects against NO production. To identify the active compounds, we conducted micro-filtration membrane, ethanol-added separation, and anion exchange and gel permeation chromatography; the purified polysaccharide (PPS) was subsequently obtained. PPS significantly inhibited NO production, prostaglandin-E2 (PGE2) production and suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW 264.7 cells. Thus, PPS inhibited NO and PGE2 production via the inhibition of iNOS and COX-2. These results indicate that the anti-inflammatory activity of PPS may be attributable to the modulation of anti-inflammatory agents. [Copyright &y& Elsevier]

Highlights: [•] The Ecklonia cava extract tested herein evidenced profound adipogenesis inhibition. [•] The three polyphenol compounds of phlorotannins were isolated from E. cava. [•] Dieckol exhibited greatest potential adipogenesis inhibition. [•] Dieckol significantly reduced the expression of adipogenic-specific genes and proteins. [•] Dieckol inhibits adipogenesis by activating the AMPK pathway. [ABSTRACT FROM AUTHOR]

Abstract: Alcoholic liver disease, which is one of the most serious liver disorders, has been known to cause by ethanol intake. In the present study, in vivo hepatoprotective effects of dieckol-rich phlorotannins (DRP) from Ecklonia cava, a brown seaweed, on ethanol induced hepatic damage in BALB/c mice liver were investigated. After administration of 5 and 25mg/kg mouse of DRP and 4g/kg mice ethanol, the body weights and survival rates were increased as compared to the control, which is ethanol-treated group without DRP. The glutamic oxaloacetic transaminase and glutamic pyruvic transaminase levels in the serum were lower than those of the control. DRP exhibited a reduction of the total cholesterol. The lower levels of SOD enzyme and a reduction of the formation of malondialdehyde were occurred in mice fed with 5 and 25mg/kg mouse of DRP. Finally the effect on improvement of fatty liver induced by ethanol was observed by taking out the liver immediately after dissecting the mouse. However, no significant difference was observed on hepatic histopathological changes. In conclusion, this study indicated that DRP could protect liver injury induced by ethanol in vivo. It suggested that DRP possesses the beneficial effect to human against ethanol-induced liver injury. [Copyright &y& Elsevier]