IRS1/PI3K/AKT pathway signal involved in the regulation of glycolipid metabolic abnormalities by Mulberry (Morus alba L.) leaf extracts in 3T3-L1 adipocytes

Background Mulberry (Morus alba L.) leaf tea benefits the control of diabetes in Asian nations. This study was aim to investigate if the flavonoids, which extracts from mulberry leaves, could regulate the metabolism of glycolipid, and to investigate if flavonoids could regulate IRS1/PI3K/AKT pathway signal to affect the expression of FAS and membrane transfer capacity GLUT4 in 3T3-L1 adipocytes. Results Results revealed that flavonoids decreased the levels of free fatty acid and increased the glucose consumption and the levels of adiponectin and leptin in a dose-dependent manner, and remarkably increased the protein expression levels of p-IRS1, p-PI3K, p-Akt, total GLUT4, and membrane GLUT4, and decreased the protein expression levels of PTEN and FAS in 3T3-L1 adipocytes IR model. On the other hand, wortmannin (2 nM), a selective and irreversible PI3K inhibitor, significantly decreased the glucose consumption and the adiponectin and leptin levels, and increased the free fatty acid level in flavonoids treated 3T3-L1 adipocytes IR model. Furthermore, wortmannin (2 nM) partly eliminated the activation of PI3K/AKT signaling, the suppression of FAS, and the up-regulated membrane transfer capacity of GLUT4 in flavonoids treated 3T3-L1 adipocytes IR model. Conclusion In conclusion, our results illustrated that mulberry leaf extracts flavonoids alleviated the glycolipid metabolic abnormalities in 3T3-L1 adipocytes IR model, and the effect was associated with the activation of IRS1/PI3K/AKT pathway, the suppression of FAS, and the up-regulation of membrane transfer capacity of GLUT4.