title: Phlorotannins isolated from the edible brown alga Ecklonia stolonifera exert anti-adipogenic activity on 3T3-L1 adipocytes by downregulating C/EBPα and PPARγ.
abstract: The dramatic increase in obesity-related diseases emphasizes the need to elucidate the cellular and molecular mechanisms underlying fat metabolism. Inhibition of adipocyte differentiation has been suggested to be an important strategy for preventing or treating obesity. In our previous study, we characterized an Ecklonia stolonifera extract and non-polar fractions thereof, including dichloromethane and ethyl acetate fractions. We showed that these fractions inhibited adipocyte differentiation and lipid formation/accumulation in 3T3-L1 preadipocytes, as assessed by Oil Red O staining. As part of our ongoing search for anti-obesity agents derived from E. stolonifera, in this work, we characterized five known phlorotannins, including phloroglucinol, eckol, dieckol, dioxinodehydroeckol, and phlorofucofuroeckol A, all of which were isolated from the active ethyl acetate fraction of E. stolonifera. We determined the chemical structures of these phlorotannins through comparisons of published nuclear magnetic resonance (NMR) spectral data. Furthermore, we screened these phlorotannins for their abilities to inhibit adipogenesis over a range of concentrations (12.5-100 μM). Of these five phlorotannins, phloroglucinol, eckol, and phlorofucofuroeckol A significantly concentration-dependently inhibited lipid accumulation in 3T3-L1 cells without affecting cell viability. In addition, the five isolated phlorotannins also significantly reduced the expression levels of several adipocyte marker genes, including proliferator activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), although they did so to different extents. These results suggest that the molecular weight of a phlorotannin is an important factor affecting its ability to inhibit adipocyte differentiation and modulate the expression levels of adipocyte marker genes.
authors: Department of Food Science and Human Nutrition, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors: Hyun Ah
authors: HA
authors: Jung
authors: Department of Food and Life Science, Pukyong National University, 608-737, Republic of Korea.
authors: Hee Jin
authors: HJ
authors: Jung
authors: Department of Life Science and Biotechnology, Dong-Eui University, Busan 614-714, Republic of Korea.
authors: Hyun Young
authors: HY
authors: Jeong
authors: Department of Life Science and Biotechnology, Dong-Eui University, Busan 614-714, Republic of Korea.
authors: Hyun Ju
authors: HJ
authors: Kwon
authors: Department of Food and Life Science, Pukyong National University, 608-737, Republic of Korea.
authors: Md Yousof
authors: MY
authors: Ali
authors: Department of Food and Life Science, Pukyong National University, 608-737, Republic of Korea. Electronic address: choijs@pknu.ac.kr.
authors: Jae Sue
authors: JS
authors: Choi
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects*; D000818:Animals; D019440:Anti-Obesity Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004147:Dioxins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D015536:Down-Regulation; D051379:Mice; D009765:Obesity / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D000459:Phaeophyceae / Q000737:chemistry*; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D013634:Tannins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D019440:Anti-Obesity Agents; D022763:CCAAT-Enhancer-Binding Protein-alpha; D022762:CCAAT-Enhancer-Binding Proteins; C530718:CEBPA protein, mouse; D004147:Dioxins; D047495:PPAR gamma; D010936:Plant Extracts; D013634:Tannins; C060311:eckol
keywords: 3T3-L1 cells; Adipocyte differentiation; C/EBPα; Ecklonia stolonifera; Obesity; PPARγ