芫荽中脂烯酰基载体蛋白还原酶抑制成分及其作用机理研究

The appearance of antibiotic-resistant bacteria has steadily increased to become a serious health problem. With the emergence of vancomycin-resistant Staphylococcus aureus in 2002, there is an urgent need for new antibiotics. One approach to combat antibiotic resistance is to identity new drugs that function through novel mechanisms of action. Fatty acid synthesis (FAS) in bacterial is essential to the production of a number of lipid-containing components, including the cell membranes. Bacterial fatty acid synthesis is carried out by a set of individual enzymes which are collectively known as type Ⅱ,while mammalian fatty acid is mediated by a single multifunctional enzyme-acyl carrier protein(ACP) complex referred to as type Ⅰ. FabI is an enoyl-ACP reductase which catalyzes the final and rate-limiting step of the chain elongation process of the type ⅡFAS. Since there is a lack of an overall sequence homolog with the corresponding one of humans, FabI has been identified as a target for antibacterial drug development. New FabI inhibitors have been screened from natural resources for discovery of new anti-bacterial lead compound. The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. Coriander (Coriandrum sativum L.), widely spread in the world, was planted large area in China. It was used as a spicy additive for food and as herbal remedies due to their biologically active compounds and have been proven to have antimicrobial and anti-oxidative effects. The main effective compositions were existed in its seed essential oil. The program led to the selection of Coriander seed essential oil in isolation and purification active compounds from molecular level research on the mechanism of its antibacterial activity. This research while leveraging the Changbai mountain development provides the theoretical basis of antibiotics and supplements to conventional antimicrobial additives in foods.

脂肪酸合成途径Ⅱ(FASⅡ)是大多数原核生物合成脂肪酸的方式，由这一途径合成的脂肪酸再经过一系列生化过程形成细胞膜磷脂疏水蛋白等生命物质。脂烯酰基载体蛋白还原酶(FabI）是催化FASⅡ中最终步骤的酶，研究开发作用于该酶的抑制剂有可能发现新型抗菌药物。本项目通过对长白山地区产中药芫荽有效成分的分离与纯化，从分子水平研究其抗菌作用机制，促进对中药预防和治疗细菌感染机制的具体认识，为中药抗菌剂的基础研究提供新的活性化合物，同时为利用长白山地区中药资源开发抗菌药物和纯天然防腐剂提供理论依据。

脂肪酸合成途径Ⅱ(FASⅡ)是大多数原核生物合成脂肪酸的方式，由这一途径合成的脂肪酸再经过一系列生化过程形成细胞膜磷脂疏水蛋白等生命物质。脂烯酰基载体蛋白还原酶(FabI）是催化FASⅡ中最终步骤的酶，研究开发作用于该酶的抑制剂有可能发现新型抗菌药物。本研究主要对芫荽、泽泻、紫苏、厚朴等植物的抑菌活性成进行分离、纯化和结构鉴定，从分子水平探讨其抗菌作用机理。研究结果发现芫荽中分离得到的芫荽异香豆精、二氢芫荽异香豆精体外抑制FabI的 IC50分别为为15.1μM和18.3μM， fab I基因过表达金黄色葡萄球菌和正常金黄色葡萄球菌实验结果也证明了上述两个化合物的作用靶点为FabI。芫荽籽油对小鼠全身感染动物模型具有很好的保护作用，芫荽与肉桂、厚朴组成的复方可显著增加其制剂稳定性和活性；紫苏叶中首次分离得到香树脂醇和5-羟基-6,7-甲氧基黄酮，并首次报道其抗菌活性；厚朴中首次报道辣薄荷基厚朴酚的抑菌活性；朝药泽泻提取物中分离得到9个活性化合物，首次报道了23-乙酰泽泻醇B、23-乙酰泽泻醇C、泽泻醇B、泽泻醇、环氧泽泻烯等化合物的抗菌活性。，本项目研究结果为利用长白山地区中药资源开发抗菌药物和天然防腐剂提供了理论依据。