- 作者: 葉小帆; 周政賢; 林麗娟; 蕭明熙
- 作者服務機構: 陽明醫學院生化所; 榮民總醫院醫學研究部
- 中文摘要:
目前從真菌靈芝中完全鑑定出的固醇與氧化型三?類天然物種類已超過l00種,且知有多對的氧化型三?類互呈表
異構物或位置異構物,其氧化位置主要在羊毛 烷基架的C-3,C-15,C-22,C-23與C-26位置。很顯然地靈芝屬是研究
三?類異戊二烯化合物的生合成及氧化型生物轉化很好的系統。本報告利用(RS)-[2- C] mevalonate當標示先質,追
?靈芝液相培養中轉化成二種主要三?型次級代謝物的階段及轉化效率,並利用(RS)-[5- C] mevalonate配合 C-
NMR方法,確定其合成遵守異戊二烯架構的方式,此安定性同位素標示追?結果亦有利於再確定此型三?天然物的 C-
NMR譜之指認。由於在液相培養的菌絲體中亦可產生3-oxo型中間物,我們推測,C-3處β經基轉化成α型的異構作
用是經由氧化-還原途徑方式進行的。
是 - 英文摘要: More than one hundred species of steroids and oxygenated triterpenoids have been determined fromthe fungus Ganoderma lucidum (Fr.) Karst in the past few years. Structurally, many lanostanoid triter-penoids were found to contain oxygenated functionalities, particularly at C-3, C-15, C-22, C-23 and C-26.The co-occurrence of oxygenated triterpenoids as C-3 epimers and C-3/C-15 positional isomers in pairs isparticularly interesting from the biosynthetic point of view and deserves further study. In this paper wereport the incorporation of (RS)-[2- C]-mevalonate into two major triterpenoids, which are C-3 epimersin pair, by the liquid culture of G. lucidum. It provides information about the production and percentageincorporation in this fungal system. The (RS)-[5-C]-mevalonate incorporation and 13C-NMR techniquesconfirm their isoprenoid origin and also support our previous 13C-NMR assignment. The occurrence of3-oxo lanostanoid intermediate in the mycelial culture leads us to speculate that the formation of C-3α typetriterpenoids are transformed from the C-3β isomers by oxidation-reduction processes.
- 中文關鍵字: oxygenated triterpenoids; biosynthesis; isotope labeling; 13C-NMR; Ganoderma lucidum
- 英文關鍵字: --