以天然产物活性分子为模板，通过进行构效关系及计算机辅助优化设计研究，是创制无公害渔药的一条重要途径，其中从植物中分离筛选获得活性分子是开发无公害渔药的基础和前提。本项目以对鱼类危害最大的寄生原生动物之一的小瓜虫为研究对象，依据其生活史和感染的不同特点对影响药物活性检测的几个重要因素进行最适化探讨，并依此建立药效评价体外和感染动物模型。以此模型检测的抗虫活性为指导，对前期研究初步筛选的具有潜在抗虫活性的目标中草药应用吸附柱色谱、凝胶柱色谱、高效液相色谱、气相色谱等分离技术进行抗虫活性分子分离筛选研究，并最终通过波谱解析、化学元素分析等分析技术对其结构进行鉴定；或直接活性检测确定前期研究分离筛选的活性分子的抗虫活性，以期筛选出植物源抗寄生原虫活性分子。该项目的研究可以为新渔药原料药的创制提供借鉴。同时，也为今后无公害渔药的创新研究提供新思路和新方法，具有重要的科学理论意义和应用前景。

Taking pharmacology activity molecules from natural products as templates, a study on the structure-activity relationship and the computer assisted optimization design is performed, which provides a shortcut to develop the green fishery drugs. Screening and isolating the activity molecules from botanicals is the basis for further botanical drug development in aquaculture. The parasitic protozoan Ichthyophthirius multifiliis probably accounting for more damage to freshwater fish populations worldwide than any other eukaryote pathogen, was used to the research object for this project. According to different characteristics of life cycle and infestation of this parasite, a series of pharmacodynamical evaluation models for in vitro and in vivo were built based on the optimization of sereral important conditions affecting drug activity detection. Under the guidance of antiparasitic activity detected by the above models, the activity molecules were separated by absorption chromatography、gel permeation chromatography、high performance liquid chromatography、gas chromatography and their separation techniques from botanicals with potential antiparasitic activity based on our preliminary study and reports, and the structures of these molecules were determined through the spectrum analysis、chemical elements analysis and the other analysises; meanwhlie, antiparasitic activity of several molecules obtained from our preliminary study was also determined. This study tries to identify botanical antiparasitic molecules in order to provide some reference for creation of bulk pharmaceuticals in aquaculture. Also, it may provide a novel idea and model for development of green fishery drug, and is of profound theoretical and practical significance.