Hui-Jeon Jeon¹, Kye-Yoon Yoon¹, Eun-Jeong Koh¹, Jia Choi¹, Kui-Jin Kim¹, Hyeon-Son Choi², Boo-Yong Lee^1,

Ecklonia cava, a brown alga native to the seas of Korea and Japan, contains biologically active polyphenols. Seapolynol (SN) is a polyphenol mixture derived from Ecklonia cava, and dieckol (DK) is a major compound of SN. Both Ecklonia cava-derived polyphenols exert an anti-diabetic effect in C57BL/KsJ-db/db mice. SN and DK supplementation significantly reduced bodyweight, water intake, fasting blood glucose, and plasma insulin levels compared with db/db mice. In addition, C-peptide, a biomarker of insulin secretion, was significantly decreased by SN and DK treatment, whereas plasma adiponectin levels, which are associated with insulin sensitivity, was increased by two-fold compared with the db/db group. Regarding plasma lipid profiles, triacylglycerol, total cholesterol, and low-density lipoprotein (LDL) cholesterol, were effectively reduced in the SN- and DK-treated groups. Moreover, the administration of SN and DK activated the insulin signaling pathway, as indicated by the levels of receptor substrate-1 (IRS-1), phosphoinositide 3-kinase (PI3K), serine-threonine specific protein kinase (Akt), and glucose transporter type 4 (GLUT4) in diabetic mice. This result showed that SN and DK regulate blood glucose levels by improving insulin sensitivity in the diabetic condition. Our data suggest that SN and DK may be anti-diabetic agents.

Seapolynol, Dieckol, Type 2 diabetes, C57BL/KsJ-db/db mice, IRS-1