Hepatoprotective constituents of the edible brown alga Ecklonia stolonifera on tacrine-induced cytotoxicity in Hep G2 cells.
ABSTRACT In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with EC50 values of 62.0 and 79.2 microg/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an EC50 value of 50.0 microg/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.
- SourceAvailable from: Hyeung-Rak Kim[Show abstract] [Hide abstract]
ABSTRACT: Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been implicated in various inflammatory diseases. In this study, we investigated the anti-inflammatory activities of Chondria crassicaulis ethanolic extract (CCE) by measuring its effects on the expression of iNOS and COX-2 proteins in lipopolysaccharide (LPS)-treated RAW 264.7 murine macrophages. CCE significantly and dose-dependently inhibited the LPS-induced release of nitric oxide and prostaglandin , and suppressed the expression of iNOS and COX-2 proteins in LPS-stimulated RAW 264.7 cells, without causing any cytotoxicity. It also inhibited the production of the pro-inflammatory cytokines such as interleukin (IL)-, IL-6, and tumor necrosis factor (TNF)- in LPS-stimulated RAW 264.7 cells. Moreover, treatment with CCE strongly suppressed nuclear factor- (NF-) promoter-driven expression in LPS-treated RAW 264.7 cells. CCE treatment blocked nuclear translocation of the p65 subunit of NF- by preventing proteolytic degradation of inhibitor of . These results indicate that CCE regulates iNOS and COX-2 expression through NF--dependent transcriptional control, and identifies potential candidates for the treatment or prevention of inflammatory diseases.Fisheries and aquatic sciences. 12/2011; 14(4).
- [Show abstract] [Hide abstract]
ABSTRACT: Bacterial lipopolysaccharide (LPS) induces expression of pro-inflammatory cytokines and enzymes producing nitric oxide (NO) and prostaglandins (PGs) in immune cells. This process is mediated by the activation of nuclear factor kappaB (NF-). In this study, we investigated the anti-inflammatory characteristics of Codium fragile ethanolic extract (CFE) mediated by the regulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) using LPS-stimulated murine macrophage RAW 264.7 cells. CFE significantly inhibited LPS-induced NO and production in a dose-dependent manner and suppressed the expression of iNOS and COX-2 proteins in LPS-stimulated RAW 264.7 cells with no cytotoxicity. Pro-inflammatory cytokines, such as interleukin (IL)-, IL-6, and tumor necrosis factor-, were significantly reduced by treatment of CFE in LPS-stimulated RAW 264.7 cells. CFE inhibited the promoter activity of (NF)- in LPS-stimulated macrophages. Treatment with CFE suppressed translocation of the NF- p65 subunit by preventing proteolytic degradation of inhibitor of . These results indicate that the CFE-mediated inhibition of NO and production in LPS-stimulated RAW 264.7 cells is mediated through the NF--dependent transcriptional downregulation of iNOS and COX-2, suggesting the potential of CFE as a nutraceutical with anti-inflammatory activity.Fisheries and aquatic sciences. 12/2011; 14(4).
- [Show abstract] [Hide abstract]
ABSTRACT: The laver (Porphyra tenera), red seaweed, has been reported to have anticancer activity, but little is known about its molecular mechanisms of action. The objective of this study was to determine the effects of laver extract on cancer cell proliferation, invasion, and metastasis in SK-Hep1 cells using migration and invasion assays. We also investigated the relationship of MMP-2/-9 and TIMP-1/-2 expression at both the protein and gene level in SK-Hep1 human hepatoma carcinoma cells after laver extract treatment. Laver extract inhibited cancer cell growth in a dose-dependent manner. In an invasion assay conducted in Transwell chambers, laver extract showed 19.6 and 27.2% inhibition of cancer cell at 200 and 400 μg/mL, respectively, compared to the control. The mRNA levels of both MMP-2 and MMP-9 were down-regulated by laver extract treatment in a dose-dependent manner. Laver extract, at 400 μg/mL, was inhibited by MMP-2 and MMP-9 expressions by 70.1 and 77.0%, respectively. An inverse relationship in the mRNA contents of MMP-2/-9 and TIMP-1/-2 expressions in SK-Hep1 cells was found by laver extract treatment. Our results demonstrate antimetastatic properties of laver extract in inhibiting the adhesion, invasion, and migration of SK-Hep1 human hepatoma cancer cells.Bioscience Biotechnology and Biochemistry 06/2014; 78(6):1044-51. · 1.27 Impact Factor