Biotransformation of Cycloastragenol by Cunninghamella blakesleeana NRRL 1369 Resulting in a Novel Framework
摘要:
The microbial transformation of cycloastragenol by the fungus Cunninghamella blakesleeana NRRL 1369 was investigated. Unlike the original compound, the metabolite was found to possess an interesting triterpenic skeleton derived via an exceptional transformation involving ring cleavage and methyl group migration. The structure of the new metabolite was elucidated by 1-D (H-1, C-13) and 2-D NMR (COSY, HMBC, HMQC, NOESY) techniques and MS analyses.
Cycloastragenol是一种环烷烷型三萜,具有显着的端粒酶激活活性。本文研究了两株丝状真菌,即Syncephalastrum racemosum AS 3.264和Alternaria alternata AS 3.4578对丝状真菌的生物催化作用。扩大的生物转化反应产生了27种代谢产物。它们的结构是在广泛的NMR和HR-ESI-MS数据分析的基础上确定的,其中18种是新化合物。这两种真菌菌株表现出不同的生物催化特征。S.蔓可以催化环膨胀和环氧化反应,以形成3β,10β-环氧或6α,19α环氧-9,10-开环-cycloartane结构,而链格孢优选催化乙酰化反应,尤其是在3-OH,6-OH和19-OH下。这些区域和立体选择性反应很难通过化学方法实现,但可以在温和条件下通过生物催化实现。此外,我们发现一些50μM的乙酰化衍生物可以将秀丽隐杆线虫的寿命从对照组的16.93±0.70 d显着延长至20
作者:Melis Kuban、Gaye Öngen、Ikhlas A. Khan、Erdal Bedir
DOI:10.1016/j.phytochem.2012.12.007
日期:2013.4
The microbial transformation of cycloastragenol by the fungi Cunninghamella blakesleeana NRRL 1369 and Glomerella fusarioides ATCC 9552, and the bacterium Mycobacterium sp. NRRL 3805 were investigated. Both fungi mainly provided hydroxylated metabolites together with products formed by cyclization, dehydrogenation and Baeyer-Villiger oxidation resulting in a ring cleavage. The bacteria yielded only a single oxidation product, namely, 3-oxo-cycloastragenol. Structures of the metabolites were elucidated by 1-D (H-1,C-13), 2-D NMR (COSY, HMBC, HMQC) and HRMS analyses. (C) 2013 Elsevier Ltd. All rights regerved.