石榴皮中三萜酸成分及其降糖活性研究

Pomegranate peel is the main by-product in the process of pomegranate.They are generally treated as wastage, resulting in a serious waste of resources. Triterpenic acids as important natural products have been widely used in health food, biomedicine and other fields. Because the chemical structure of triterpenic acids is complexity and the chemical synthesis is very difficult, they are mainly extracted from plants.Our previous study found pomegranate peel contained a variety of triterpenic acids (oleanolic acid, ursolic acid, etc.). The hypoglycemic activity was also evaluated. Results showed the extracts can significantly improve the level of blood glucose and lipid. For example，triterpenic acids exhibited similar effects with rosiglitazone in glucose tolerance test, and showed stronger activity than rosiglitazone on the regulation of blood lipids. Based on the preliminary studies, this project focuses on the studies below. Triterpenic acids in pomegranate peel will be separated and identified, and their hypoglycemic activity will be screened. A practical and effective method for triterpene acid separation from pomegranate peel and the HPLC fingerprint of triterpene acids will be established. The cell experiment model and animal experiment model will be employed to evaluate the hypoglycemic effect of the seperated triterpenic acid, and the hypoglycemic mechanism will be investigated. This project will be meaningful for clarifing the active ingredients and the full utilization of pomegranate peel. Furthermore, it could provide important information for the research and development of new antidiabetic functional factors or functional foods. Thus, this project possesses the significant theory and application value.

石榴皮是石榴加工中主要副产品，一般作为废弃物处理，造成资源严重浪费。三萜酸是天然产物中一类重要活性化合物，广泛应用于保健食品、生物医药等领域，由于化学结构复杂，人工合成困难，目前均来自植物提取。我们前期研究发现石榴皮含多种三萜酸(齐墩果酸、熊果酸等)，并对三萜酸部位进行了降糖活性研究，发现其具有很好的降糖调脂作用，如改善糖耐量效果与罗格列酮相近，在改善血脂方面明显强于罗格列酮。在前期研究基础上，本课题将对石榴皮中三萜酸成分进行系统分离、鉴定及降糖活性筛选；建立简便实用、快速有效的石榴皮三萜酸富集纯化方法；建立不同产地石榴皮三萜酸HPLC指纹图谱；利用细胞实验及动物实验综合评价三萜酸降糖效果，并初步探讨其降糖活性机制。本课题的实施有助于阐明和丰富石榴皮活性物质基础内涵，为石榴加工副产品的开发利用提供科学依据，为研究和开发新型降糖功能因子及功能食品奠定理论基础，具有重要理论意义和应用价值。

本项目围绕石榴加工副产物-石榴皮中三萜酸活性成分开展研究，建立了石榴皮中三萜酸富集纯化工艺，对三萜酸成分进行系统分离与鉴定，填补石榴皮三萜酸类成分研究空白，并运用动物实验模型对石榴皮三萜酸进行降糖效果评估。同时建立了基于新型荧光标记探针标记的高灵敏三萜酸测定方法，并利用该方法对石榴皮中三萜酸进行定量检测。同时开发了采用了基于分散液液微萃取技术的三萜酸快速、简便、灵敏、高效、环保的富集浓缩方法，成功应用于石榴皮中的三萜酸的快速富集，获得了比较满意的分析结果。建立了基于a-葡萄糖苷酶活性抑制的糖尿病药物筛选传感器，该方法可以实现痕量降糖活性成分的筛选，比现有的检测方法灵敏度提高了3个数量级，我们利用该方法对石榴皮中分离出的三萜酸进行活性检测，筛选出石榴皮中具有降糖活性的三萜酸化合物。同时为了全面了解石榴皮中三萜酸的口服生物利用度，我们首次开发一种选择性好、灵敏度高的三萜酸生物利用度研究方法，并将其应用于三萜酸的生物利用度研究，同时考察了环糊精对于提高三萜酸的生物利用度效果进行了评价。 此外，项目组对石榴皮中多不饱和脂肪酸进行了定性及定量分析；还对石榴生产中的副产物-石榴花多糖进行了提取工艺、单糖组成、抗氧化活性进行了研究。以上研究为石榴加工副产品的开发与利用提供科学依据，为研究和开发新型降糖功能因子及降糖功能食品奠定理论基础，具有重要的理论意义和应用价值。