New oxidized sterols from Aspergillus awamori and the endo‐boat conformation adopted by the cyclohexene oxide system |
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| Authors: | Hao Gao Kui Hong Guo‐Dong Chen Chuan‐Xi Wang Jin‐Shan Tang Yang Yu Miao‐Miao Jiang Man‐Mei Li Nai‐Li Wang Xin‐Sheng Yao |
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| Institution: | 1. Institute of Traditional Chinese Medicine & Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, P. R. China;2. Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicin and New Drugs Research, Jinan University, Guangzhou 510632, P. R. China;3. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P. R. China;4. Institute of Tropical Biosciences and Biotechnology, Haikou 571101, P. R. China;5. Traditional Chinese Medicine College, Shenyang Pharmaceutical University, Shenyang 110016, P. R. China |
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| Abstract: | Two new oxidized sterols 1 and 2 were obtained from the active fraction of a mangrove fungus Aspergillus awamori isolated from the soils around the mangrove plant Acrostichum speciosum. Their structures were elucidated using spectroscopic methods as 22E‐7α‐methoxy‐5α,6α‐epoxyergosta‐8(14),22‐dien‐3β‐ol (1) and 22E‐3β‐hydroxy‐5α,6α,8α,14α‐diepoxyergosta‐22‐en‐7‐one (2). The NMR data and complete assignments for both DMSO‐d6 and CDCl3 were given. Their cytotoxic activity against A549 cell line was evaluated. Furthermore, the detailed conformation analysis for ring B (cyclohexene oxide system) of sterol 1 was given on the basis of NOEs. The endo‐boat conformation was considered as the preferred conformation for ring B rather than half‐chair conformation. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | 1H NMR 13C NMR 2D NMR Aspergillus awamori mangrove fungus 5α 6α ‐epoxy sterols cytotoxic activity endo‐boat conformation cyclohexene oxide |
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