Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Nanhai Road 7, Qingdao 266071, People's Republic of China.
J Nat Prod. 2010 Nov 29;73(11):1780-4. doi: 10.1021/np100386q. Epub 2010 Nov 2.
7-Nor-ergosterolide (1), a rare 7-norsteroid with an unusual pentalactone B-ring system, and two new steroid derivatives, 3β,11α-dihydroxyergosta-8,24(28)-dien-7-one (2) and 3β-hydroxyergosta-8,24(28)-dien-7-one (3), were characterized from the culture extract of Aspergillus ochraceus EN-31, an endophytic fungus isolated from the marine brown alga Sargassum kjellmanianum. In addition, nine known related steroids were isolated and identified. The structures of these compounds were established on the basis of extensive spectroscopic analysis. The absolute configuration of the new steroids (1-3) was determined by application of the modified Mosher's method. Compound 1, which represents the first example of a 7-nor-ergosteroid possessing a pentalactone B-ring system in a naturally occurring steroid, displayed cytotoxicity against NCI-H460, SMMC-7721, and SW1990 cell lines with IC(50) values of 5.0, 7.0, and 28.0 μg/mL, respectively. Compound 2 also displayed cytotoxicity against the SMMC-7721 cell line with an IC(50) value of 28.0 μg/mL.
7-降-麦角甾-6,22-二烯-3β-醇（1），一种罕见的具有不寻常的五内酯 B-环系统的 7-降甾体，以及两种新的甾体衍生物，3β，11α-二羟基麦角甾-8,24（28）-二烯-7-酮（2）和 3β-羟基麦角甾-8,24（28）-二烯-7-酮（3），从海洋棕色海藻 Sargassum kjellmanianum 内生真菌 Aspergillus ochraceus EN-31 的培养提取物中得到鉴定。此外，还分离并鉴定了 9 种已知的相关甾体。这些化合物的结构是基于广泛的光谱分析确定的。新甾体（1-3）的绝对构型通过应用改进的 Mosher 法确定。化合物 1 是自然界中第一个具有五内酯 B-环系统的 7-降麦角甾-6,22-二烯-3β-醇，对 NCI-H460、SMMC-7721 和 SW1990 细胞系显示出细胞毒性，IC50 值分别为 5.0、7.0 和 28.0 μg/mL。化合物 2 对 SMMC-7721 细胞系也显示出细胞毒性，IC50 值为 28.0 μg/mL。
