Evaluation of 7-O-galloyl-d-sedoheptulose, isolated from Corni Fructus, in the adipose tissue of type 2 diabetic db/db mice

Abstract

The aim of the present study was to evaluate the beneficial effects of 7-O-galloyl-d-sedoheptulose (GS), isolated from Corni Fructus, using type 2 diabetic mice. GS was orally administered to db/db mice at doses of 20 and 100mg/kg body weight per day for 6weeks, and the effects of GS on biochemical factors in serum and adipose tissue were investigated. To define the underlying mechanism of these effects, protein expressions related to lipid metabolism, inflammation, fibrosis, and apoptosis, were measured. The results showed that levels of glucose, leptin, insulin, C-peptide, resistin, tumor necrosis factor-α, interleukin-6, triglycerides, total cholesterol, non-esterified fatty acids, high-density lipoprotein cholesterol, very low-density lipoprotein cholesterol/low-density lipoprotein cholesterol, reactive oxygen species (ROS), and thiobarbituric acid-reactive substance (TBARS) in serum were down-regulated, while adiponectin was augmented by GS treatment. In addition, the elevated lipid, ROS, and TBARS contents in adipose tissue as well as serum levels in db/db mice were significantly decreased by the oral administration of GS. From protein analysis, the decreased expressions of peroxisome proliferator activated receptor (PPAR)α, PPARγ, and B-cell lymphoma 2 were up-regulated in the adipose tissue of db/db mice. The administration of GS significantly decreased sterol regulatory element binding protein-1, nuclear factor-kappa ?>Bp65, cyclooxygenase-2, inducible nitric oxide synthase, monocyte chemotactic protein-1, intracellular adhesion molecule-1, phosphor c-Jun N-terminal kinase, activator protein-1, transforming growth factor-β1, Bax, cytochrome c, and caspase-3 expressions. These results suggest that GS acts as a regulator of oxidative stress, inflammation, fibrosis, and apoptosis in the adipose tissue of db/db mice.