PHYTOALEXIN ELICITORS AS INDUCERS OF MEDICINAL CONSTITUENTS IN SOME PLANT CELL CULTURES.

植物病原真菌或植物细胞壁片段作为信号分子，在转导水平上诱导植物抗毒素的生物合成。植物抗毒素只有在被病原体感染时才会大量产生。植物抗毒素的结构多种多样，但通常具有与正常代谢物相同的骨架。换句话说，植物抗毒素与正常代谢物共享大部分生物合成途径。这些事实表明，在植物细胞培养物中添加激发子可能会增加在正常培养条件下无法实现的有用代谢物的产生。在本研究中，研究了不同的激发子对葛根和麻黄细胞培养中药物成分产生的影响。葛根细胞培养在正常条件下产生大豆苷元及其苷类。添加大孢子疫霉糖蛋白组分可使大豆苷元及其糖苷的产量提高5 ~ 7倍，并可诱导大量合成翼虫胺类植物抗菌素tuberosin。相反，在许多豆科植物中被认为是最活跃的激发子的同一真菌的葡聚糖部分几乎没有表现出任何作用，这表明即使属于同一科的植物对同一激发子的反应也不同。果胶酶释放的酵母提取物和葛根细胞壁片段具有相似的作用，通过激活生物合成酶增加了异黄酮的产量。这些激发子诱导产生了三种不同类型的大豆素二聚体。考虑到酵母已被用作食品和（或）食品添加剂及其可用性，酵母提取物在工业应用中比其他激发剂具有很大的优势。研究了不同来源的诱导子对麻黄碱的生物合成的激活作用。用酵母浸膏诱导不明黄色色素，生物碱产量无显著增加。麻黄碱缺乏抗生素活性可能解释了这一观察结果。少

Cell wall fragment of phytopathogenic fungi or plants acts as a signal molecule and induces biosynthesis of phytoalexins at transduction level. Phytoalexins are produced in large quantities by plants only when they are infected by pathogens. Structure of phytoalexins diverses but usually possesses the same skeleton as normal metabolites. In other words phytoalexins share most of their biosynthetic routes with normal metabolites. These facts suggest that the addition of elicitors to the plant cell cultures might increase the production of useful metabolites which can not be achieved under normal culture conditions. In this study, effects of various elicitors on the production of medicinal constituents in cell cultures of Pueraria lobata and Ephedra distachya were investigated. Cell cultures of Pueraria lobata produce daidzein and its glycosides under normal conditions. Addition of the glycoprotein fraction of Phytophthora megasperma increased the production of daidzein and its glycoside … More s by 5 to 7 folds, and induced the biosynthesis of pterocarpan phytoalexin tuberosin in large amounts. On the contrary, the glucan fraction of the same fungi which has been claimed to be the most active elicitor in many Leguminous plants showed almost no effects indicating that even the plants belonging to the same family respond differently to the same elicitor. Yeast extract and cell wall fragments of Pueraria lobata released by pectinase showed the similar effects and increased the production of isoflavonoids through activation of biosynthetic enzymes. Production of three different types of daidzein dimer were induced by these elicitors. Considering that yeast has been used as foods and or food additives and its availability, yeast extract has great advantages over other elicitors in industrial applications. Some elicitors of different origin were tested for their activation effects on the biosynthesis of ephedra bases in cell cultures of E. distachya. No significant increase of alkaloid production was observed though unidentified yellow pigment was induced with yeast extract. Lack of antibiotic activity of ephedra bases might account for this observations. Less