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

植物病原真菌或植物的细胞壁碎片作为信号分子，在转导水平上诱导植物保卫素的生物合成。只有当植物受到病原体感染时，植物才会大量产生植物保健素。植物抗毒素的结构不同，但通常具有与正常代谢物相同的骨架。换句话说，植物保健素的大部分生物合成途径与正常的代谢物相同。这些事实表明，在植物细胞培养中加入激发子可能会增加有用代谢物的产量，而这在正常培养条件下是不可能实现的。本研究考察了不同诱导子对葛根和麻黄细胞培养生产药用成分的影响。葛根细胞培养在正常条件下产生大豆苷元及其苷元。添加大疫霉糖蛋白部分可提高大豆苷元及其糖苷…的产量提高S产量5~7倍，并诱导大量合成蕨类植物保鲜蛋白。相反，在许多豆科植物中被认为是最活跃的激发子的同一种真菌的葡聚糖组分几乎没有任何作用，这表明即使是属于同一科的植物对相同的激发子也有不同的反应。果胶酶释放的葛根酵母膏和细胞壁碎片也表现出类似的作用，并通过激活生物合成酶增加了异黄酮类化合物的产量。这些激发子诱导产生了三种不同类型的大豆苷元二聚体。考虑到酵母已被用作食品和/或食品添加剂，以及其可用性，酵母抽提物在工业应用中具有其他诱导子无法比拟的优势。研究了几种不同来源的激发子对稻瘟病菌细胞培养物中麻黄碱合成的激活作用。酵母膏诱导未鉴定黄色素的生物碱产量未见明显增加。麻黄碱缺乏抗生素活性可能解释了这一观察结果。较少

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