基于濒危药用植物霍山石斛资源保护和利用的药材品质的影响因素研究

As a rare and endangered medicinal orchidaceous plant, Dendrobium huoshanense C. Z. Tang et S. J. Cheng is well-known for its great activities such as strengthen human immunopotency, protection from cardiovascular disease, anticancer, etc. Our previous phytochemical investigation of this plant revealed that remarkable differences in both contents and composition of active components are existed between wild D. huoshanense and test-tube plantlet tamed stock. This caused the lower quality of test-tube plantlet tamed D. huoshanense and became a bottleneck of the germplasm resource conservation and utilization of the endangered medicinal plant. .In order to approach the possible reason of the quality decreasion of test-tube plantlet tamed D. huoshanense and keep its quality stable, the referring NSFC proposal firstly desigined to investigate the main bioactive components of secondary metabolites obtained by systematic isolation from D. huoshanense. Then the Med Mat evaluation criterion are established by the finger prints based on the main active components. The relationship between the production of active secondary metabolites and the exist of endogenic mycetes is explored by the study on the origin of different bioactive chemicals in the plant D. huoshanense. At last, the contribution of the major environmental factors to the accumulation of active components is elucidated through imitating the wild habitat of the rare and endangered plant. Thus, the accumulation rule of the pharmacodynamic material basis of D. huoshanense might be demonstrated. Our proposal may provide theoretical basis for the quality control of test-tube plantlet medicinal plants and for how to solve the key bottleneck of the resource conservation and utilization of D. huoshanense, and will also offer a model for the protection of the whole endangered medicinal plants.

霍山石斛(D. huoshanense)为濒危兰科药用植物，具有增强免疫、预防心血管疾病、抗肿瘤等功效。我们前期研究发现，霍山石斛试管苗移栽驯化植株虽然保持了形态和遗传的稳定，但药效物质基础的组成和含量发生改变，导致药材品质下降，成为制约霍山石斛种质资源保护和利用的瓶颈和难题之一。本课题拟以野生霍山石斛组分分离获得主要活性物质为标示物，建立基于药效物质基础指纹图谱的质量评价标准，以此为依据，对霍山石斛主要活性成分的基源展开研究，探讨其主要活性成分的产生和积累与内生真菌的关系。在此基础上，通过内生真菌再侵入试管苗仿原生驯化栽培，研究光照、温度、湿度等主要环境因子对霍山石斛活性成分积累的影响，阐明霍山石斛药材品质形成机制，为药用植物资源保护和利用过程中药材品质控制、解决霍山石斛种质资源保护和资源利用的关健制约因素奠定理论基础，对其它濒危药用植物资源保护研究起示范作用。

运用现代生物技术，通过组织培养快速获得试管苗进而野外驯化栽培，已成为濒危植物霍山石斛资源保护的主要方法。然而，霍山石斛试管苗移栽驯化植株与野生植株试化学成分存在明显差异的问题，导致试管苗途径霍山石斛品质下降成为困扰霍山石斛资源保护和利用的难题。本项目对导致这种差异的原因进行了系统的探索，对霍山石斛内生真菌及次生代谢产物进行了分离，共从霍山石斛中分离出153株菌株、93种小分子单体化合物、6个单一多糖，构建了基于HPLC-DAD/ELSD /Q-TOF、HPLC-GPC、FTIR、2DCOS IR、GC-MS、pCEC等分析技术的霍山石斛次生代谢产物组分分析方法，确定了霍山石斛主要次生代谢产物的基源，在此基础上，成功培育了与野生植株化学成分相似度较高的、高产的霍山石斛新品系霍山石斛3号、霍山石斛4号，有效的解决了试管苗途径霍山石斛组培植株与其野生植株组分差异较大问题。本研究对于阐明霍山石斛药材品质形成机制、探讨“组培育种→野外驯化栽培”模式对珍稀濒危药用植物种质资源保护中药材“种”稳定，“质”下降的机制及药材品质控制策略、解决霍山石斛种质资源保护和利用的关健制约因素奠定理论基础，在方法学上为其它珍稀濒危药用植物种质资源保护和可持续利用提供参考。