Hepatoprotective constituents of the edible brown algaEcklonia 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.

Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitory Phlorotannins from Edible Brown Algae,Ecklonia stoloniferaandEisenia bicyclis

“…17) Phlorotannins are secondary metabolites polymerizing phloroglucinol (1,3,5-trihydroxybenzene) through an ether, phenyl, or 1,4-dibenzodioxin linkage. These polyphenolic compounds are responsible for a variety of bioactivities, including anti-diabetic complications, 17,18) and antitumorial, 19) hepatoprotective, 20) anti-plasmin inhibiting, 21) algicidal, 22) tyrosinase inhibiting, 23) antiinflammatory, 24,25) nitrite-scavenging, 26) anti-skin aging, 27,28) antioxidative, [29][30][31] anti-cholinesterase, 32,33) antiAlzheimer, 34) anti-hyperlipidemic, 35) anti-diabetic, [36][37][38][39] anti-allergic, 40) and angiotensin converting enzyme-I inhibitory activities. 41) As part of our continuous search for antidiabetic agents from natural sources, we investigated the MeOH extract and solvent-soluble fractions of the two selected brown algae, E. stolonifera and E. bicyclis, together with six isolated phlorotannins against -glucosidase and PTP1B.…”

Hepatoprotection by chemical constituents of the marine brown algaSpatoglossum variabile: A relation to free radical scavenging potential

“…They are also reported to be rich sources of bioactive natural substances with antioxidant and hepatoprotective potential. Some bioactive metabolites from seaweeds, such as sulfated polysaccharides, have antiviral activity, and other metabolites such as Kahalalide F from Bryopsis species are possible drug candidates for the treatment of lung cancer and tumors (Wong et al, 2000;Smit, 2004;Kim et al, 2005;Iwaki, 2008). The hypolipidemic activities of ethanol extracts of Spatoglossum asperum J.Agardh (Dictyoaceae), Solieria robusta (Grev.)…”

Antiulcer, wound healing and hepatoprotective activities of the seaweeds Gracilaria crassa, Turbinaria ornata and Laurencia papillosa from the southeast coast of India

“…The hepatoprotective nature of the brown seaweeds Sargassum polycystem and that of Ecklonia stolonifera against acetaminophen induced hepatic damage in rats (Balaji Raghavendran et al, 2004) and tacrine-induced cytotoxicity in Hep G2 cells (Kim et al, 2005) holds well for the activity in T. ornata. The present observation of dose dependent activity in the three seaweed extracts coincided with the observation of Wong et al (2000) in Myagropsis myagroides and Sargassum henslowianum.…”