Abstract：
Insulin secretion and GLUT4 expression are two critical events in glucose regulation. The receptors G-protein-coupled receptor 40 (GPR40) and peroxisome proliferator-activated receptor-gamma (PPARγ) modulate these processes, and they represent potential therapeutic targets for new antidiabetic agent\'s design. Cucurbita ficifolia fruit is used in traditional medicine for diabetes control. Previous studies demonstrated several effects: a hypoglycemic effect mediated by an insulin secretagogue action, antihyperglycemic effect, and promoting liver glycogen storage. Anti-inflammatory and antioxidant effects were also reported. Moreover, some of its phytochemicals have been described, including d-chiro-inositol. However, to understand these effects integrally, other active principles should be investigated. The aim was to perform a chemical fractionation guided by bioassay to isolate and identify other compounds from C. ficifolia fruit that explain its hypoglycemic action as insulin secretagogue, its antihyperglycemic effect by PPARγ activation, and on liver glycogen storage. Three different preparations of C. ficifolia were tested in vivo. Ethyl acetate fraction derived from aqueous extract showed antihyperglycemic effect in an oral glucose tolerance test and was further fractioned. The insulin secretagogue action was tested in RINm5F cells. For the PPARγ activation, C2C12 myocytes were treated with the fractions, and GLUT4 mRNA expression was measured. Chemical fractionation resulted in the isolation and identification of β-sitosterol and 4-hydroxybenzoic acid (4-HBA), which increased insulin secretion, GLUT4, PPARγ, and adiponectin mRNA expression, in addition to an increase in glycogen storage. 4-HBA exhibited an antihyperglycemic effect, while β-sitosterol showed hypoglycemic effect, confirming the wide antidiabetic related results we found in our in vitro models. An in silico study revealed that 4-HBA and β-sitosterol have potential as dual agonists on PPARγ and GPR40 receptors. Both compounds should be considered in the development of new antidiabetic drug development.
摘要：
胰岛素分泌和GLUT4表达是葡萄糖调节中的两个关键事件。受体G蛋白偶联受体40（GPR40）和过氧化物酶体增殖物激活受体γ（PPARγ）调节这些过程，它们代表了新型抗糖尿病药物设计的潜在治疗靶点。西葫芦果实在传统药物中用于控制糖尿病。先前的研究证明了几种作用：由胰岛素促分泌作用介导的降血糖作用，抗高血糖作用，促进肝糖原储存。还报道了抗炎和抗氧化作用。此外，它的一些植物化学物质已经被描述过，包括d-chiro-肌醇。然而,为了完整地理解这些影响，应该调查其他积极的原则。目的是通过生物测定法进行化学分馏，以分离和鉴定C.ficifolia果实中的其他化合物，这些化合物解释了其作为胰岛素促分泌素的降血糖作用，其通过PPARγ激活的降血糖作用，和肝糖原储存。在体内测试了三种不同的花叶草制剂。来自水性提取物的乙酸乙酯级分在口服葡萄糖耐量测试中显示出抗高血糖作用，并进一步进行了分级。在RINm5F细胞中测试了胰岛素促分泌作用。对于PPARγ激活，C2C12肌细胞用馏分处理，测量GLUT4mRNA表达。化学分馏导致β-谷甾醇和4-羟基苯甲酸（4-HBA）的分离和鉴定，增加胰岛素分泌，GLUT4、PPARγ、和脂联素mRNA表达，除了糖原储存的增加。4-HBA表现出抗高血糖作用，β-谷甾醇有降血糖作用,证实了我们在体外模型中发现的广泛的抗糖尿病相关结果。一项计算机模拟研究表明，4-HBA和β-谷甾醇具有作为PPARγ和GPR40受体双重激动剂的潜力。在新的抗糖尿病药物的开发中应该考虑这两种化合物。
