Hepatoprotective constituents of the edible brown alga Ecklonia stolonifera on tacrine-induced cytotoxicity in Hep G2 cells

College of Pharmacy, Wonkwang University, Iksan, Korea.
Archives of Pharmacal Research (Impact Factor: 2.05). 01/2006; 28(12):1376-80. DOI: 10.1007/BF02977904
Source: PubMed


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.

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    • "With regard to pharmaceutical use, brown algal phlorotannins have been demonstrated to have a number of biological functions, including hepatoprotective activity (Kim et al., 2005), an antiallergic effect (Shibata, Fujimoto, Nagayama, Yamaguchi, & Nakamura, 2002), an antidiabetic effect (Iwai, 2008), and an antioxidative effect (Kang et al., 2003). From a chemical and structural point-of-view, phlorotannins are polymers and oligomers of 1,3,5-trihydroxybenzene (phloroglucinol ) and can be classified into four subclasses based on the means of linkage, as follows: viz. "
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    ABSTRACT: In this study, a hydrophilic interaction chromatography (HILIC) condition was developed for the simultaneous determination of five major phlorotannins from an extract of Eisenia bicyclis (Kjellman) Setchell with good linearity (r(2)>0.999). Based on this method, the seasonal variations and extraction characteristics, in terms of total extraction yield and the content of the phlorotannins, were investigated under various extraction conditions. In results, the yields and phlorotannins were increased two-to-four times in summer (June-October) and then, were decreased to normal levels in winter (November-March). In the extraction of E. bicyclis, ethanol percentage in water, extraction time and washing time significantly affected the yield of the extract and the phlorotannins, whereas the temperature and the sample/solvent ratio impacted the extraction to a lesser degree. These results will be useful information in the application of this macroalga in the commercial areas related to nutraceuticals, pharmaceuticals, and cosmeceuticals.
    Food Chemistry 06/2013; 138(4):2399-406. DOI:10.1016/j.foodchem.2012.11.057 · 3.39 Impact Factor
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    • "Phlorotannins are marine brown algal polyphenols produced by polymerization of phloroglucinol (1,3,5-trihydroxybenzene) (Ragan and Glombitza, 1986). Phlorotannins have been shown to possess diverse biological activities, including antioxidation (Kang et al., 2005; Zou et al., 2008), reduction of diabetic complications (Okada et al., 2004) and amnesia (Yoon et al., 2008), and chemoprevention (Kang et al., 2003; Kim et al., 2005). Recent studies have also demonstrated that phlorotannins from a brown algae, Eisenia bicyclis, inhibit activities of hyaluronidase, phospholipase A 2 , lipoxygenase, and COX enzymes (Shibata et al., 2003). "
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    ABSTRACT: Microglial activation has been implicated in many neurological disorders for its inflammatory and neurotrophic effects. In this study, we investigated the effects of phlorofucofuroeckol A isolated from Ecklonia stolonifera Okamura on the production of inflammatory mediators in lipopolysaccharide (LPS)-stimulated microglia. Pre-treatment of phlorofucofuroeckol A attenuated the productions of nitric oxide, prostaglandin E(2), and pro-inflammatory cytokines in LPS-stimulated microglia. Profoundly, phlorofucofuroeckol A treatment showed inactivation of nuclear factor-κB (NF-κB) by preventing the degradation of inhibitor κB-α and the nuclear translocation of p65 NF-κB subunit. Moreover, phlorofucofuroeckol A inhibited the activation of c-Jun NH(2)-terminal kinases (JNKs), p38 mitogen-activated protein kinase (MAPK), and Akt, but not that of extracellular signal-regulated kinase. These results indicate that phlorofucofuroeckol A inhibits the LPS-induced expression of inflammatory mediators through inactivation of NF-κB, JNKs, p38 MAPK, and Akt pathways. These findings suggest that phlorofucofuroeckol A can be considered as a nutraceutical candidate for the treatment of neuroinflammation in neurodegenerative diseases.
    Inflammation 09/2012; 36(2). DOI:10.1007/s10753-012-9542-6 · 2.21 Impact Factor
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    • "um catenella . 1 . 2 . 2 . 7 . Hepatoprotective activity . Phloroglucinol ( Cross et al . , 1907 ) and phloroglucinol derivatives eckstolonol , ( Kang et al . , 2003 ) eckol , phlorofucofuroeckol A ( Fukuyama et al . , 1990 ) and dieckol ( Fukuyama et al . , 1983 ) were isolated from the brown alga Ecklonia stolonifera as hepatoprotective agents ( Kim et al . , 2005 ) ."
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    ABSTRACT: Marine organisms are potentially prolific sources of highly bioactive secondary metabolites that might represent useful leads in the development of new pharmaceutical agents. Algae can be classified into two main groups; first one is the microalgae, which includes blue green algae, dinoflagellates, bacillariophyta (diatoms)… etc., and second one is macroalgae (seaweeds) which includes green, brown and red algae. The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Moreover, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. Red algae are considered as the most important source of many biologically active metabolites in comparison to other algal classes. Seaweeds are used for great number of application by man. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry.
    Saudi Pharmaceutical Journal 01/2010; 18(1):1-25. DOI:10.1016/j.jsps.2009.12.001 · 1.28 Impact Factor
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