Zhang Yi, Li Xiao-Ming, Proksch Peter, Wang Bin-Gui
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Steroids. 2007 Sep;72(9-10):723-7. doi: 10.1016/j.steroids.2007.05.009. Epub 2007 Jun 9.
Ergosterimide (1), a natural Diels-Alder adduct of ergosteroid and maleimide, was characterized from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from the marine brown alga Colpomenia sinuosa. In addition, four known steroids including (22E,24R)-ergosta-5,7,22-trien-3beta-ol (2), (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (3), (22E,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (4), and (22E,24R)-ergosta-7,22-dien-3beta,5alpha,6beta-triol (5) were also isolated and identified. The structures of these compounds were elucidated by extensive analysis of 1D and 2D NMR and IR spectra and MS data. The plausible biosynthetic pathway of 1 was also discussed. To the best of our knowledge, 1 is the first natural Diels-Alder adduct of steroid and maleimide reported so far.
麦角甾胺（1）是一种麦角甾醇与马来酰亚胺的天然狄尔斯-阿尔德加成物，从黑曲霉EN-13的培养提取物中分离得到，该菌株是从海洋褐藻海带中分离出的一种内生真菌。此外，还分离并鉴定了四种已知的甾体化合物，包括（22E，24R）-麦角甾-5,7,22-三烯-3β-醇（2）、（22E，24R）-麦角甾-4,6,8（14）,22-四烯-3-酮（3）、（22E，24R）-5α,8α-环氧麦角甾-6,22-二烯-3β-醇（4）和（22E，24R）-麦角甾-7,22-二烯-3β,5α,6β-三醇（5）。通过对一维和二维核磁共振、红外光谱和质谱数据的广泛分析，阐明了这些化合物的结构。还讨论了化合物1可能的生物合成途径。据我们所知，化合物1是迄今为止报道的首例甾体与马来酰亚胺的天然狄尔斯-阿尔德加成物。
