British Journal of Nutrition

Full Papers

Flaxseed lignan attenuates high-fat diet-induced fat accumulation and induces adiponectin expression in mice

S. Fukumitsua1, K. Aidaa1, N. Uenoa1, S. Ozawaa2, Y. Takahashia3 and M. Koboria3 c1

a1 Nippon Flour Mills Co. Ltd., Central Laboratory, 5-1-3 Midorigaoka, Atsugi, Kanagawa 243-0041, Japan

a2 Rakuno Gakuen University, 582-1 Bunkyodai-Midorimuchi, Ebetsu, Hokkaido 069-8501, Japan

a3 National Food Research Institute, 2-1-12, Kannondai, Tuskuba, Ibaraki 305-8642, Japan

Abstract

Flaxseed lignan secoisolariciresinol diglucoside (SDG) has been reported to prevent and alleviate lifestyle-related diseases including diabetes and hypercholesterolaemic atherosclerosis. This study assesses the effect of SDG on the development of diet-induced obesity in mice and the effect of the SDG metabolite enterodiol (END) on adipogenesis in 3T3-L1 adipocytes. We compared body weight, visceral fat weight, liver fat content, serum parameters, mRNA levels of lipid metabolism-related enzymes and adiponectin in mice fed either a low-fat diet (5 % TAG), high-fat diet (30 % TAG) or high-fat diet containing 0·5 and 1·0 % (w/w) SDG for 4 weeks. Administration of SDG to mice significantly reduced high-fat diet-induced visceral and liver fat accumulation, hyperlipaemia, hypercholesterolaemia, hyperinsulinaemia and hyperleptinaemia. SDG also suppressed sterol regulatory element binding protein 1c mRNA level in the liver and induced increases in the adiponectin mRNA level in the white adipose tissue and carnitine palmitoyltransferase I mRNA level in the skeletal muscle. Differentiated 3T3-L1 adipocytes were treated with 0, 5, 10 and 20 μmol/l END and then assayed for mRNA expression of adipogenesis-related genes and DNA binding activity of PPARγ to the PPAR response element consensus sequence. END induced adipogenesis-related gene mRNA expression including adiponectin, leptin, glucose transporter 4 and PPARγ, and induced PPARγ DNA binding activity in 3T3-L1 adipocytes. In conclusion, SDG induced adiponectin mRNA expression and showed beneficial effects on lipid metabolism in diet-induced obesity in mice. Flaxseed lignans are suggested to regulate adipogenesis-related gene expressions through an increase in PPARγ DNA binding activity.

(Received September 11 2007)

(Revised November 16 2007)

(Accepted December 13 2007)

(Online publication February 06 2008)

Correspondence:

c1 Corresponding author: Dr Masuko Kobori, fax +81 29 838 7996, email kobori@affrc.go.jp

Footnotes

Abbreviations: CPT-1, carnitine palmitoyltransferase I; DMEM, Dulbecco's modified Eagle's medium; END, enterodiol; ENL, enterolactone; PPRE, PPAR response element; SDG, secoisolariciresinol diglucoside; SREBP-1c, sterol regulatory element binding protein 1c