The Catharanthus roseus plant has been used traditionally to treat diabetes mellitus. Scientific evidence supporting the antidiabetic effects of this plant’s active ingredient-vindoline has not been fully evaluated. In this study, extracts of C. roseus and vindoline were tested for antioxidant activities, alpha amylase and alpha glucosidase inhibitory activities and insulin secretory effects in pancreatic RIN-5F cell line cultured in the absence of glucose, at low and high glucose concentrations. The methanolic extract of the plant showed the highest antioxidant activities in addition to the high total polyphenolic content (p < 0.05). The HPLC results exhibited increased concentration of vindoline in the dichloromethane and the ethylacetate extracts. Vindoline showed noticeable antioxidant activity when compared to ascorbic acid at p < 0.05 and significantly improved the in vitro insulin secretion. The intracellular reactive oxygen species formation in glucotoxicity-induced cells was significantly reduced following treatment with vindoline, methanolic and the dichloromethane extracts when compared to the high glucose untreated control (p < 0.05). Plant extracts and vindoline showed weaker inhibitory effects on the activities of carbohydrate metabolizing enzymes when compared to acarbose, which inhibited the activities of the enzymes by 80%. The plant extracts also exhibited weak alpha amylase and alpha glucosidase inhibitory effects.

中文翻译：

---

长春花不同提取物及其吲哚生物碱文多林的体外抗糖尿病和抗氧化作用

长春花植物传统上用于治疗糖尿病。支持这种植物活性成分文多林抗糖尿病作用的科学证据尚未得到充分评估。在这项研究中，在没有葡萄糖的情况下，在低和高葡萄糖浓度下培养的胰腺 RIN-5F 细胞系中，测试了 C. roseus 和文多林提取物的抗氧化活性、α 淀粉酶和 α 葡萄糖苷酶抑制活性以及胰岛素分泌作用。除了高总多酚含量外，该植物的甲醇提取物还显示出最高的抗氧化活性（p < 0.05）。HPLC 结果显示二氯甲烷和乙酸乙酯提取物中文多林的浓度增加。与抗坏血酸相比，文多林显示出明显的抗氧化活性，p < 0。05并显着改善体外胰岛素分泌。与高葡萄糖未处理对照相比，在用文多林、甲醇和二氯甲烷提取物处理后，葡萄糖毒性诱导细胞中细胞内活性氧的形成显着减少（p < 0.05）。与阿卡波糖相比，植物提取物和文多林对碳水化合物代谢酶活性的抑制作用较弱，阿卡波糖对酶的活性抑制了 80%。植物提取物还表现出弱的α淀粉酶和α葡萄糖苷酶抑制作用。与高葡萄糖未处理对照相比，甲醇和二氯甲烷提取物 (p < 0.05)。与阿卡波糖相比，植物提取物和文多林对碳水化合物代谢酶活性的抑制作用较弱，阿卡波糖对酶的活性抑制了 80%。植物提取物还表现出弱的α淀粉酶和α葡萄糖苷酶抑制作用。与高葡萄糖未处理对照相比，甲醇和二氯甲烷提取物 (p < 0.05)。与阿卡波糖相比，植物提取物和文多林对碳水化合物代谢酶活性的抑制作用较弱，阿卡波糖对酶的活性抑制了 80%。植物提取物还表现出弱的α淀粉酶和α葡萄糖苷酶抑制作用。