New α-pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
New α-pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
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DOI：
10.1016/j.bioorg.2021.105452
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发表时间：
2021-11-04
影响因子：
5.1
通讯作者：
Zhang, Yonghui
中科院分区：
文献类型：
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作者：
Li, Fengli;Ye, Zi;Zhang, Yonghui
从从菊科植物毛白菜(Siegesbeckia Pubescens Makino)鲜叶中分离得到的油菜链格孢菌(Alternaria Brassicola)中，分离得到3对未知对映体α-pymne衍生物(1a/1b-3a/3b)和6个未知同系物(4-9)。这些新化合物的结构通过广泛的核磁共振波谱和HRESIMS数据进行了表征，并通过改进的Mosher方法、化学转化、单晶X-射线衍射分析和ECD计算进一步确定了它们的绝对构型。这是首次报道从油菜曲霉中分离得到的三对对映体α-吡喃酮类化合物，并通过手性高效液相色谱从规模化混合物中成功地获得了这些对映体。对化合物1a/1b-3a/3b和4-9进行了除草活性评价，结果表明，化合物1a/1b-3a/3b和4-9具有较好的除草活性。化合物1a和1b对单子叶杂草种子萌发有明显的抑制作用，其抑制率为68.6+/-6.4%~84.2+/-5.1%，与阳性对照草甘膦相当。讨论了这些化合物的潜在结构与除草活性的关系。在一定程度上，本研究的结果将引起人们对真菌代谢产物α-Pymne衍生物作为环保型除草剂的潜在实际应用的极大兴趣。
Three pairs of undescribed enantiomeric alpha-pymne derivatives (1a/1b-3a/3b) and six undescribed congeners (4-9), were obtained from the fungus Alternaria brassicicola that was isolated from the fresh leaves of Siegesbeckia pubescens Makino (Compositae). The structures of these new compounds were characterized by extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were further elucidated by a modified Mosher's method, chemical conversion, single-crystal X-ray diffraction analysis, and ECD calculations. This is the first report of three pairs of enantiomeric alpha-pyrone derivatives from the fungus A. brassicicola, and these enantiomers were successfully acquired from scalemic mixtures via chiral HPLC. Compounds 1a/1b-3a/3b and 4-9 were evaluated for the herbicidal activity against Echinochloa crusgalli, Setaria viridis, Portulaca oleracea, and Taraxacum mongolicum. At a concentration of 100 mu g/mL, compounds la and lb could significantly inhibit the germination of monocotyledon weed seeds (E. crusgalli and S. viridis) with inhibitory ratios ranging from 68.6 +/- 6.4% to 84.2 +/- 5.1%, which was equivalent to that of the positive control (glyphosate). The potential structure-herbicidal activity relationship of these compounds was also discussed. To a certain extent, the results of this study will attract great interest for the potential practical application of promising fungal metabolites, alpha-pymne derivatives, as ecofriendly herbicides.