唐古特白刺果实中α-葡萄糖苷酶抑制剂的发现及其降血糖作用机制研究

Diabetes has become one of the major chronic diseases affecting the global population health, and its prevalence has increased year by year. Effective control of postprandial blood glucose (PBG) is an important method for treating diabetes and preventing complications. α-glucosidase inhibitors have shown good clinical effects in controlling PBG and improving diabetic complications. Nitraria tangutorum has a good effect in treating diabetes in medical records and folk use. Previous studies in this laboratory have conducted preliminary studies on its chemical composition and α-glucosidase inhibitory activity. It was confirmed that the ethanol extract of Nitraria tangutorum has significant in vivo and in vitro α-glucosidase inhibitory activity, and has potential for development and application. In order to clarify the active ingredient in Nitraria tangutorum and its hypoglycemic mechanism, this project intends to further clarify the structure type, effect and mechanism of active ingredients on the basis of previous studies. Targeted separation technology was used to clarify the structure and structure-activity relationship of active ingredients. Molecular and animal models were used to evaluate hypoglycemic activity. On this basis, enzyme kinetics and molecular docking techniques were applied to investigate the molecular mechanism of hypoglycemic activity of active ingredients. To provide research data and scientific basis for the development of safe and effective hypoglycemic natural drugs, and to open up new ways for the full and effective use of Nitraria tangutorum resources.

糖尿病已成为影响全球人口健康的主要慢性疾病之一，患病率逐年上升。有效控制餐后血糖是治疗糖尿病和预防并发症的重要手段。α-葡萄糖苷酶抑制剂类药物在控制餐后血糖和改善糖尿病并发症方面表现出良好的临床效果。本项目的研究对象唐古特白刺，在医药典籍记载和民间使用中都有很好的治疗糖尿病的功效。本实验室的前期证实唐古特白刺果实醇提取物具有显著的体内外α-葡萄糖糖苷酶抑制活性，具有开发和应用潜力。为明确唐古特白刺中糖苷酶抑制剂活性成份及起效机制，本项目拟在前期研究的基础上进一步阐明活性成份的结构类型、作用效果及作用机制。采用靶向分离技术明确活性成分结构及构效关系，采用分子及动物模型评价降糖活性；在此基础上应用酶动力学和分子对接技术，探讨活性成分降糖作用分子机制。为开发安全、高效的降血糖天然药物提供研究数据和科学依据，为充分有效利用白刺植物资开开辟新途径

唐古特白刺主要分布于我国的西北部，为药食同源的野生植物，有着很高的经济、生态和药用价值。唐古特白刺在医药典籍记载和民间使用中都有很好的治疗糖尿病的功效，并且本实验室的前期研究证实唐古特白刺果实乙醇提取物具有显著的体内外α-葡萄糖苷酶抑制活性，具有开发和应用潜力。本研究在前期研究的基础上，以动物来源的糖苷酶（蔗糖酶和麦芽糖酶）为靶标，对唐古特白刺进行靶向制备分离及活性再筛选，筛选出白刺体内外降低餐后血糖活性组分，并通过HPLC-MS技术初步推断了该组分主要化学结构类型；采用传统柱色谱和现代制备分离手段相结合，对活性组分进行了系统深入的分离纯化及结构鉴定，从中鉴定化合物59种，主要包括生物碱类，黄酮类，酚酸类等。其中鉴定β-咔啉类新化合物8个，酚酸苷新化合物2个；对分离得到化合物进行了蔗糖酶和麦芽糖酶抑制活性再筛选，从中筛选出6个活性成分，主要为黄酮类和酚酸类，构效关系分析发现黄酮和酚酸芳环的羟基数目和位置，以及羟基甲基化或糖苷化都会对化合物的活性有较大影响；通过糖尿病小鼠蔗糖/麦芽糖/淀粉/葡萄糖耐量实验，明确了优效成分体内降低餐后血糖药效活性。此外通过酶机制和动力学研究，阐明了该成分通过竞争性的抑制蔗糖酶和麦芽糖酶活性发挥降低餐后血糖作用，同时采用分子对接技术，进一步验证了其降血糖分子机制。为天然新型α-葡萄糖苷酶抑制剂的研发提供了研究数据和科学依据，为更加充分有效利用我国丰富的白刺资源开辟了新的途径。