Department of Food Science, National Chiayi University, Taiwan, ROC.
Food Chem Toxicol. 2013 Dec;62:492-8. doi: 10.1016/j.fct.2013.09.005. Epub 2013 Sep 12.
Hyperglycemia is associated with advanced glycation end products (AGEs). Recently, AGEs were found to cause pancreatic damage, oxidative stress, and hyperglycemia through the AGE receptor. Carboxymethyllysine (CML) is an AGE but whether it induces pancreatic dysfunction remains unclear. Graptopetalum paraguayense, a vegetable consumed in Taiwan, has been used in folk medicine and is an antioxidant that protects against liver damage. We investigated the protective properties of G. paraguayense 95% ethanol extracts (GPEs) against CML-induced pancreatic damage. The results indicated that resveratrol, GPE, and gallic acid (the active compound of GPE) increased insulin synthesis via upregulation of pancreatic peroxisome proliferator activated-receptor-γ (PPARγ) and pancreatic-duodenal homeobox-1 (PDX-1) but inhibited the expression of CML-mediated CCAAT/enhancer binding protein-β (C/EBPβ), a negative regulator of insulin production. Moreover, resveratrol and GPE also strongly activated nuclear factor-erythroid 2-related factor 2 (Nrf2) to attenuate oxidative stress and improve insulin sensitivity in the liver and muscle of CML-injected C57BL/6 mice and resulted in reduced blood glucose levels. Taken together, these findings suggested that GPE and gallic acid could potentially be used as a food supplement to protect against pancreatic damage and the development of diabetes.
高血糖与晚期糖基化终产物（AGEs）有关。最近，AGEs 通过 AGE 受体被发现会导致胰腺损伤、氧化应激和高血糖。羧甲基赖氨酸（CML）是一种 AGE，但它是否会导致胰腺功能障碍尚不清楚。在台湾食用的一种蔬菜厚叶石莲花（Graptopetalum paraguayense），已被用于民间医学，是一种抗氧化剂，可防止肝损伤。我们研究了厚叶石莲花 95%乙醇提取物（GPEs）对 CML 诱导的胰腺损伤的保护作用。结果表明，白藜芦醇、GPE 和没食子酸（GPE 的活性化合物）通过上调胰腺过氧化物酶体增殖物激活受体-γ（PPARγ）和胰腺十二指肠同源盒-1（PDX-1）来增加胰岛素的合成，但抑制了 CML 介导的 CCAAT/增强子结合蛋白-β（C/EBPβ）的表达，C/EBPβ 是胰岛素产生的负调节剂。此外，白藜芦醇和 GPE 还强烈激活核因子-红细胞 2 相关因子 2（Nrf2），以减轻 CML 注射的 C57BL/6 小鼠的肝脏和肌肉中的氧化应激，并提高胰岛素敏感性，从而降低血糖水平。总之，这些发现表明，GPE 和没食子酸可能可作为一种食品补充剂，用于预防胰腺损伤和糖尿病的发生。
