西松烷二萜等特征产物介导Sinularia属软珊瑚化学生态功能及其作用机理研究

Soft corals of the genus Sinularia (Alcyoniidae) are the most dominant benthic invertebrates inhabiting mainly in tropical and subtropical seas. Chemical defense system is the main tool of Sinularia to struggle for survival in the severe competitive situations of seawater environments, possessing the capability for attack and defense, prey and predation, allelopathy and symbiosis, and occupation of food and spaces. Although the chemical ecological functions of soft corals are reported to be induced by secondary metabolites, the real purpose of typical metabolites derived from soft corals are rarely investigated. Our previous examination of chemical components of Sinularia species revealed cembranoids to be the main typical metabolites which are considered to be the chemical marks of genus Sinularia taxonomically.Detailed investigation of the typical metabolites involving the compounds with minor amount related to their chemoecological functions remains unknown, whereas it is a key point to understand the mechansims of Sinularia evoluation under competitive environments.This project intends to disclose the chemical ecological functions and the acting mechanisms of cembranoids and relative secondary metabolites derived from Sinularia species inhabited in South China Sea. Based on the established HPLC and UPLC chromatography of the total extracts from Sinularia species, the structural patterns and the diverse analogues in the fingerprints enabled to be recognized through the analyses of UV, ESIMS and 1H NMR spectral data of each chromatographic peak. In addition, fractionation of crude extract from each species led to the collection of a number of fractions, which are tested for the chemical ecological activities under the models for anti-biofouling (Hydroides elegans and Balanus amphitrite),inhibition of coral-disease caused pathogens, and ichthyotoxicity(brine shrimp and Brachydanio rerio)to uncover active metabolites or the mixtures. Analysis of structure-ecological function relationship allowed to assign the structural types and the key functional groups related to the chemical defense actions.For the potential antifouling cembranoids, the mechanisms to regulate key proteins will be uncovered to discover environmental friendly antifouling lead compounds. Moreover, comparison of HPLC spectra among the extracts from different species and the species in temporal and spatial varisation allowed to reveal the significant variability in specific defensive chemical constituents across species and a gradient of environmental parameters. Marine chemical ecology is a young science that provides significant insights into the ecology and evolution of marine organisms and the function of marine ecosystem. This project aim to systematically disclose the chemical defense strategy of Sinularia species and their survival imitation rely on the diverse secondary metabolites which varied upon the species, temporal and spatial variation.

海洋软珊瑚在繁殖与进化过程中，建立了完整化学防御体系，具备抵御异种捕食，生物附着，病原菌和异种它感等化学生态效应。为了阐明软珊瑚化学生态功能与其特征次生代谢产物的相关性以及作用机理，课题以Sinularia属软珊瑚为模式生物，建立以色谱-波谱和色谱-活性等特征成分快速组合分析技术，分析软珊瑚全成分指纹谱中西松烷二萜等特征次生代谢产物结构类别与结构多样性，阐明同属物种间和物种时空变化导致特征次生代谢产物谱的共性成分量变与差异成分结构特性与化学生态功能相关性。应用分子指纹全谱的谱-效相关性分析，阐明软珊瑚特征成分或成分组的抗病原菌，抗生物附着和拒食等抵制生态胁迫功能，并进一步分析西松烷二萜等特征产物结构或结构域与生态功能的关系。从靶分子水平阐明西松烷二萜等成分抗生物附着的作用机理。课题从特征次生代谢产物谱的变化规律与生态功能相关性探讨Sinularia属软珊瑚的生存与进化规律及其化学防御机制。

课题以海洋底栖软珊瑚Sinularia 属物种为模式海洋生物，调查了我国南海软珊瑚Sinularia 属软体动物的物种与分布，获得22种Sinularia 属物种，建立了物种全组分HPLC和UPLC指纹谱，并应用色谱-波谱联机分析技术，系统分析了6种不同海域Sinularia 属物种的次生代谢产物结构特征与结构多样性（包括微量成分）, 通过对同属不同种和同种不同海域Sinularia 属软体动物的特征产物组成和结构分析，解析了物种间的特征次生代谢产物主要为西松烷二萜类化合物，但不同种和不同海域同种的西松烷二萜类化合物的结构变化较大，表明不同海域同种生物应对的环境生物及其生态不同，形成的化学防御组成不同。阐明了245种西松烷二萜类和其他萜类化合物的分子结构，其中153种为国际上首次发现的新颖结构化合物。应用色谱组分-生态功能关系数据，阐明了特征次生代谢产物及组分与化学防御功能（抗病原菌，抗生物附着和拒食）的相关性，及其相关的药学功能，探讨了Sinularia 属西松烷二萜类等特征成分在拒食和抗附着（抗污和抗生）等活性成分与结构的相关性，并阐明了生态功能成分的作用机理。从分子水平阐明Sinularia 属软珊瑚的化学防御的本质及异种它感导致特征代谢产物的生物合成通道的变化，并系统推断了代谢特征代谢产物的生源关系。通过本课题研究，基本阐明了我国南海Sinularia 属物种的特征代谢产物的结构多样性与新颖性，为揭示Sinularia 属物种的生态功能与进化提供了分子依据。发表课题相关SCI论文34篇， 申请发明专利4项，完成了课题研究指标。