Adipose tissue is one of the major organs responsible for rapid restoration of postprandial glucose fluxes. Being the major isoform of glucose transporter in adipose tissue, regulations of insulin-dependent GLUT4 trafficking have always been of research interest. The present study aimed to examine the molecular mechanisms underlying the efficacy of curculigoside and polyphenol-rich ethyl acetate fraction (EAF) of Molineria latifolia rhizome in triggering glucose uptake. We assessed the adipogenic potential and glucose uptake stimulatory activity of curculigoside and EAF by employing a murine 3T3-L1 adipocyte model. The transcriptional and translational expressions of selected intermediates in the insulin signalling pathway were evaluated. While curculigoside neither promoted adipogenesis nor activated peroxisome proliferator activated receptor gamma, treatment with polyphenol-rich EAF resulted otherwise. However, both treatments enhanced insulin-stimulated uptake of glucose. This was coupled with increased availability of GLUT4 at the plasma membrane of the differentiated adipocytes although the total GLUT4 protein level was unaffected. In addition, the treatment increased the phosphorylation of both AKT and mTOR, which have been reported to be associated with GLUT4 translocation. The present findings proposed that curculigoside and EAF increased glucose transport activity of 3T3-L1 adipocytes via GLUT4 translocation as a result of potential mTOR/AKT activation. The more potent efficacy observed with EAF suggested potential synergistic and multi-targeted action.

脂肪组织是负责迅速恢复餐后葡萄糖通量的主要器官之一。作为脂肪组织中葡萄糖转运蛋白的主要同工型，胰岛素依赖性GLUT4转运的调控一直引起研究兴趣。本研究旨在探讨潜在的分子机理，其中仙茅苷和富多酚的乙酸乙酯提取物（Molineria latifolia）的功效根茎触发葡萄糖的摄取。我们通过采用鼠类3T3-L1脂肪细胞模型评估了仙茅苷和EAF的成脂潜能和葡萄糖摄取的刺激活性。评价了胰岛素信号传导途径中所选中间体的转录和翻译表达。尽管仙茅甙既不促进脂肪形成，也不激活过氧化物酶体增殖物激活受体γ，但否则导致了富含多酚的EAF的治疗。然而，两种治疗均增加了胰岛素刺激的葡萄糖摄取。尽管总的GLUT4蛋白水平没有受到影响，但这与分化的脂肪细胞质膜上GLUT4的可用性增加有关。此外，该处理增加了AKT和mTOR的磷酸化，据报道与GLUT4易位有关。本研究结果表明，由于潜在的mTOR / AKT激活，仙茅苷和EAF通过GLUT4易位增加了3T3-L1脂肪细胞的葡萄糖转运活性。用EAF观察到的更有效的功效表明潜在的协同作用和多目标作用。