Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
J Ethnopharmacol. 2010 May 4;129(1):23-33. doi: 10.1016/j.jep.2010.02.009. Epub 2010 Mar 1.
Insulin stimulates glucose uptake and promotes the translocation of glucose transporter 4 (Glut 4) to the plasma membrane on L6 myotubes. The aim of this study is to investigate affect of Scoparia dulcis Linn water extracts on glucose uptake activity and the Glut 4 translocation components (i.e., IRS-1, PI 3-kinase, PKB/Akt2, PKC and TC 10) in L6 myotubes compared to insulin.
Extract from TLC fraction-7 (SDF7) was used in this study. The L6 myotubes were treated by various concentrations of SDF7 (1 to 50 microg/ml) and insulin (1 to 100 nM). The glucose uptake activities of L6 myotubes were evaluated using 2-Deoxy-D-glucose uptake assay in with or without fatty acid-induced medium. The Glut 4 translocation components in SDF7-treated L6 myotubes were detected using immunoblotting and quantified by densitometry compared to insulin. Plasma membrane lawn assay and glycogen colorimetry assay were carried out in SDF7- and insulin-treated L6 myotubes in this study.
Here, our data clearly shows that SDF7 possesses glucose uptake properties on L6 myotubes that are dose-dependent, time-dependent and plasma membrane Glut 4 expression-dependent. SDF7 successfully stimulates glucose uptake activity as potent as insulin at a maximum concentration of 50 microg/ml at 480 min on L6 myotubes. Furthermore, SDF7 stimulates increased Glut 4 expression and translocation to plasma membranes at equivalent times. Even in the insulin resistance stage (free fatty acids-induced), SDF7-treated L6 myotubes were found to be more capable at glucose transport than insulin treatment.
Thus, we suggested that Scoparia dulcis has the potential to be categorized as a hypoglycemic medicinal plant based on its good glucose transport properties.
胰岛素可刺激葡萄糖摄取，并促进葡萄糖转运蛋白 4（Glut 4）向 L6 肌管的质膜转位。本研究旨在探讨与胰岛素相比，獐牙菜苦苷水提取物对 L6 肌管葡萄糖摄取活性和 Glut 4 易位成分（即 IRS-1、PI 3-激酶、PKB/Akt2、PKC 和 TC 10）的影响。
本研究使用 TLC 馏分-7（SDF7）提取物。用不同浓度的 SDF7（1 至 50μg/ml）和胰岛素（1 至 100nM）处理 L6 肌管。用 2-脱氧-D-葡萄糖摄取测定法评估 L6 肌管的葡萄糖摄取活性，并用或不用脂肪酸诱导的培养基。用免疫印迹法检测 SDF7 处理的 L6 肌管中的 Glut 4 易位成分，并通过密度测定法与胰岛素进行定量比较。在本研究中，还进行了 SDF7 和胰岛素处理的 L6 肌管的质膜草坪测定和糖原比色测定。
我们的数据清楚地表明，SDF7 具有剂量依赖性、时间依赖性和质膜 Glut 4 表达依赖性的 L6 肌管葡萄糖摄取特性。SDF7 在 L6 肌管上的最大浓度为 50μg/ml 时，在 480 分钟时可刺激与胰岛素相当的葡萄糖摄取活性。此外，SDF7 可刺激 Glut 4 表达增加并在相同时间转位至质膜。即使在胰岛素抵抗阶段（游离脂肪酸诱导），与胰岛素处理相比，SDF7 处理的 L6 肌管在葡萄糖转运方面更有能力。
因此，我们认为獐牙菜具有作为降血糖药用植物的潜力，这是基于其良好的葡萄糖转运特性。
