Research Institute for Biological Functions, Chubu University, Kasugai, Aichi, Japan.
Biofactors. 2012 Sep-Oct;38(5):372-7. doi: 10.1002/biof.1029. Epub 2012 Jun 7.
Honokiol and magnolol, ingredients of Magnolia officinalis, which is used in traditional Chinese and Japanese medicines, have been reported to have antioxidant, anticancer, and antiangiogenic effects. Effects of these compounds on glucose metabolism in adipocytes have also been reported. However, their effects on skeletal muscle glucose uptake and the underlying molecular mechanisms are still unknown. Here, we investigated the direct effects and signaling pathways activated by honokiol and magnolol in skeletal muscle cells using L6 myotubes. We found that honokiol and magnolol dose-dependently acutely stimulated glucose uptake without synergistic effects of combined administration in L6 myotubes. Treatment with honokiol and magnolol also stimulated glucose transporter-4 translocation to the cell surface. Honokiol- and magnolol-stimulated glucose uptake was blocked by the phosphatidylinositol-3 kinase inhibitor, wortmannin. Both honokiol and magnolol stimulated Akt phosphorylation, a key element in the insulin signaling pathway, which was completely inhibited by wortmannin. These results suggest that honokiol and magnolol might have beneficial effects on glucose metabolism by activating the insulin signaling pathway.
厚朴酚和木兰醇是传统中药和日本药物中使用的厚朴的成分，据报道具有抗氧化、抗癌和抗血管生成作用。这些化合物对脂肪细胞葡萄糖代谢的影响也有报道。然而，它们对骨骼肌葡萄糖摄取的影响及其潜在的分子机制仍不清楚。在这里，我们使用 L6 肌管研究了厚朴酚和木兰醇对骨骼肌细胞的直接作用和激活的信号通路。我们发现厚朴酚和木兰醇剂量依赖性地急性刺激 L6 肌管中的葡萄糖摄取，联合给药没有协同作用。厚朴酚和木兰醇处理也刺激葡萄糖转运蛋白-4向细胞表面转位。PI3K 抑制剂wortmannin 阻断了厚朴酚和木兰醇刺激的葡萄糖摄取。厚朴酚和木兰醇都能刺激胰岛素信号通路中的关键元件 Akt 磷酸化，而 wortmannin 则完全抑制了这一作用。这些结果表明，厚朴酚和木兰醇可能通过激活胰岛素信号通路对葡萄糖代谢产生有益影响。
