Shu-Jing Wu1, Yi-Jou Tung1, Lean-Teik Ng2. 1. Department of Nutritional Health, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan. 2. Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan. Electronic address: nglt97@ntu.edu.tw.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Grifola frondosa (GF), a high value medicinal mushroom, is popularly consumed as traditional medicines and health foods in China and Japan. It is a herbal medicine traditionally used for treating inflammation, cancer and diabetes. AIM OF THE STUDY: This study aimed to examine the anti-diabetic effects of a GF bioactive compound ergosterol peroxide (EPO), and its mechanism(s) of action in palmitate (PA)-induced C2C12 cells. MATERIALS AND METHODS: EPO was isolated and purified from GF fruiting bodies, and used to test for anti-diabetic activity in PA-induced murine C2C12 skeletal muscle cells through measuring glucose uptake, intracellular ROS production, and expressions of MAPKs, IRS-1, PI3K, Akt and GLUT-4 proteins. RESULTS: EPO significantly up-regulated glucose absorption and increased cell growth. At 5 μM, EPO significantly enhanced glucose uptake and decreased ROS formation, as well as up-regulated the expression of IRS-1, p-IRS-1, PI3K, Akt, p-Akt, and GLUT-4 proteins in PA-induced cells, while their p-JNK and p-p38 expression were down-regulated. GLUT-4 siRNA treatment effectively down-regulated the EPO-induced absorption of glucose and inhibited the expression of GLUT-4. CONCLUSION: These results suggest that the anti-diabetic effect of GF was from its bioactive compound EPO through the inhibition of ROS production, up-regulation of glucose absorption, and modulation of PI3K/Akt, MAPKs and GLUT-4 signaling transduction pathways.
ETHNOPHARMACOLOGICAL RELEVANCE: Grifola frondosa (GF), a high value medicinal mushroom, is popularly consumed as traditional medicines and health foods in China and Japan. It is a herbal medicine traditionally used for treating inflammation, cancer and diabetes. AIM OF THE STUDY: This study aimed to examine the anti-diabetic effects of a GF bioactive compound ergosterol peroxide (EPO), and its mechanism(s) of action in palmitate (PA)-induced C2C12 cells. MATERIALS AND METHODS:EPO was isolated and purified from GF fruiting bodies, and used to test for anti-diabetic activity in PA-induced murineC2C12 skeletal muscle cells through measuring glucose uptake, intracellular ROS production, and expressions of MAPKs, IRS-1, PI3K, Akt and GLUT-4 proteins. RESULTS:EPO significantly up-regulated glucose absorption and increased cell growth. At 5 μM, EPO significantly enhanced glucose uptake and decreased ROS formation, as well as up-regulated the expression of IRS-1, p-IRS-1, PI3K, Akt, p-Akt, and GLUT-4 proteins in PA-induced cells, while their p-JNK and p-p38 expression were down-regulated. GLUT-4 siRNA treatment effectively down-regulated the EPO-induced absorption of glucose and inhibited the expression of GLUT-4. CONCLUSION: These results suggest that the anti-diabetic effect of GF was from its bioactive compound EPO through the inhibition of ROS production, up-regulation of glucose absorption, and modulation of PI3K/Akt, MAPKs and GLUT-4 signaling transduction pathways.