Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences , Guangzhou 510650, People's Republic of China.
Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
J Nat Prod. 2015 Aug 28;78(8):1841-7. doi: 10.1021/acs.jnatprod.5b00099. Epub 2015 Jul 22.
Two new polycyclic tetramate macrolactams, lysobacteramides A (1) and B (2), together with HSAF (heat-stable antifungal factor, 3), 3-dehydroxy HSAF (4), and alteramide A (5) were isolated from a culture of Lysobacter enzymogenes C3 in nutrient yeast glycerol medium. Their structures were determined by MS and extensive NMR analysis. The absolute configurations of 1-5 were assigned by theoretical calculations of their ECD spectra. Although HSAF and analogues were reported from several microorganisms, their absolute configurations had not been established. The isolation and the absolute configurations of these compounds revealed new insights into the biosynthetic mechanism for formation of the polycycles. Compounds 1-4 exhibited cytotoxic activity against human carcinoma A549, HepG2, and MCF-7 cells with IC50 values ranging from 0.26 to 10.3 μM. Compounds 2 and 3 showed antifungal activity against Fusarium verticillioides with IC50 value of 47.9 and 6.90 μg/mL, respectively.
从 Lysobacter enzymogenes C3 的培养物中，在营养酵母甘油培养基中分离到两种新的多环四肽大环内酯类化合物 lysobacteramides A (1) 和 B (2)，以及 HSAF（热稳定抗真菌因子，3）、3-去氢 HSAF（4）和 alteramide A（5）。通过 MS 和广泛的 NMR 分析确定了它们的结构。通过对其 ECD 光谱的理论计算，确定了 1-5 的绝对构型。尽管 HSAF 和类似物已从几种微生物中报道，但它们的绝对构型尚未确定。这些化合物的分离和绝对构型揭示了形成多环化合物的生物合成机制的新见解。化合物 1-4 对人癌细胞 A549、HepG2 和 MCF-7 具有细胞毒性，IC50 值范围为 0.26-10.3 μM。化合物 2 和 3 对 F. verticillioides 表现出抗真菌活性，IC50 值分别为 47.9 和 6.90 μg/mL。
