Gelidium elegans extract ameliorates type 2 diabetes via regulation of MAPK and PI3K/Akt signaling

Abstract

Gelidium elegans, a red alga native to the Asia Pacific region, contains biologically active polyphenols. We conducted a molecular biological study of the anti‐diabetic effect of Gelidium elegans extract (GEE) in C57BL/KsJ‐db/db mice. Mice that had been administered GEE had significantly lower body mass, water consumption, and fasting blood glucose than db/db controls. Moreover, hemoglobin A1c (HbA1c), an indicator of the glycemic status of people with diabetes, was significantly lower in mice that had been administered GEE. We also found that 200 mg/kg/day GEE upregulates the insulin signaling pathway by activating insulin receptor substrate‐1 (IRS‐1) and phosphoinositide 3‐kinase (PI3K), and increasing the expression of glucose transporter type 4 (GLUT4). In parallel, mitogen‐activated protein kinase (MAPK) activity was lower in GEE‐treated groups. In summary, these findings indicate that GEE regulates glucose metabolism by activating the insulin signaling pathway and downregulating the MAPK signaling pathway.