Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Wufeng, Taiwan, ROC.
J Ethnopharmacol. 2009 Oct 29;126(1):79-85. doi: 10.1016/j.jep.2009.08.006. Epub 2009 Aug 12.
Cinnamomum osmophloeum is used for various ethnomedical conditions in Taiwan including diabetic complications.
The aim of present study was to identify the anti-diabetic compounds from C. osmophloeum leaves and evaluate the preliminary molecular basis for their insulin-like effects.
Silica gel column chromatographic purification of MeOH extract from leaves of C. osmophloeum resulted in the isolation of a two kaempferol glycosides CO-1 and CO-2. These two compounds were evaluated for their effects on adiponectin secretion, tyrosine phosphorylation of insulin receptor (IR)-beta and glucose transporter 4 (GLUT4) in differentiated mouse 3T3-L1 adipocytes, and the results were compared with the reference drug insulin.
The compound CO-1 at a concentration of 5 microM was able to act as an insulin-mimetic in terms of its ability to increase adiponectin secretion by 12.2-fold, while CO-2 has no such effect up to 20 microM tested. Furthermore, 5 microM of CO-1 and 20 microM of CO-2 showed potential to increase the phosphorylation of IRbeta by 2.3- and 2.1-fold, respectively, in addition to their positive effect on GLUT4 translocation. CO-1 and CO-2 stimulated GLUT4 translocation are reduced by phosphatidylinositol-3-kinase (PI3-K) inhibitor.
The present study indicates that the insulin-like anti-diabetic mechanism of constituents from C. osmophloeum leaves in part due to enhanced adiponectin secretion, and activation of insulin signaling pathway leading to GLUT4 translocation which involved phosphorylation of IR and activation of PI3-K.
肉桂在台湾被用于多种传统医学用途，包括糖尿病并发症。
本研究的目的是从肉桂叶中鉴定出具有抗糖尿病作用的化合物，并评估其胰岛素样作用的初步分子基础。
从肉桂叶甲醇提取物中通过硅胶柱色谱纯化，得到两种山柰酚糖苷 CO-1 和 CO-2。评估这两种化合物对分化的 3T3-L1 脂肪细胞中脂联素分泌、胰岛素受体（IR）-β酪氨酸磷酸化和葡萄糖转运蛋白 4（GLUT4）的影响，并与参比药物胰岛素进行比较。
化合物 CO-1 在 5μM 浓度下能够发挥胰岛素样作用，使脂联素分泌增加 12.2 倍，而 CO-2 在测试的 20μM 浓度下没有这种作用。此外，CO-1 的 5μM 和 CO-2 的 20μM 分别显示出增加 IRβ磷酸化的潜力，增加 2.3-和 2.1 倍，以及对 GLUT4 易位的积极作用。CO-1 和 CO-2 刺激 GLUT4 易位的作用被磷脂酰肌醇-3-激酶（PI3-K）抑制剂所减弱。
本研究表明，肉桂叶成分的胰岛素样抗糖尿病机制部分归因于脂联素分泌增加，以及胰岛素信号通路的激活导致 GLUT4 易位，这涉及到 IR 的磷酸化和 PI3-K 的激活。
