In the search for new antibiotic compounds, fractionation of Pseudomonas protegens UP46 culture extracts afforded several known Pseudomonas compounds, including 2,4-diacetylphloroglucinol (DAPG), as well as two new antibacterial alkaloids, 6-(pyrrolidin-2-yl)DAPG (1) and 6-(piperidin-2-yl)DAPG (2). The structures of 1 and 2 were determined by nuclear magnetic resonance spectroscopy and mass spectrometry. Compounds 1 and 2 were found to have antibacterial activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus, with minimal inhibitory concentration (MIC) 2 and 4 μg ml-1, respectively, for 1, and 2 μg ml-1 for both pathogens for 2. The MICs for 1 and 2, against all tested Gram-negative bacteria, were >32 μg ml-1. The half maximal inhibitory concentrations against HepG2 cells for compounds 1 and 2 were 11 and 18 μg ml-1, respectively, which suggested 1 and 2 be too toxic for further evaluation as possible new antibacterial drugs. Stable isotope labelling experiments showed the pyrrolidinyl group of 1 to originate from ornithine and the piperidinyl group of 2 to originate from lysine. The P. protegens acetyl transferase (PpATase) is involved in the biosynthesis of monoacetylphloroglucinol and DAPG. No optical rotation was detected for 1 or 2, and a possible reason for this was investigated by studying if the PpATase may catalyse a stereo-non-specific introduction of the pyrrolidinyl/piperidinyl group in 1 and 2, but unless the PpATase can be subjected to major conformational changes, the enzyme cannot be involved in this reaction. The PpATase is, however, likely to catalyse the formation of 2,4,6-triacetylphloroglucinol from DAPG.

中文翻译：

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细菌假单胞菌UP46的吡咯烷基和哌啶基取代的2,4-二乙酰基间苯二酚。

在寻找新的抗生素化合物时，蛋白质假单胞菌UP46培养提取物的分级分离提供了几种已知的假单胞菌化合物，包括2,4-二乙酰基间苯三酚（DAPG）以及两种新的抗菌生物碱6-（吡咯烷丁-2-基）DAPG（ 1）和6-（哌啶-2-基）DAPG（2）。1和2的结构通过核磁共振波谱法和质谱法确定。发现化合物1和2对革兰氏阳性细菌金黄色葡萄球菌和蜡状芽孢杆菌具有抗菌活性，分别对1和2μgml-1具有最小抑制浓度（MIC）2和4μgml-1 2种病原体。针对所有测试的革兰氏阴性细菌的1和2的MIC> 32μgml-1。化合物1和2对HepG2细胞的最大半数抑制浓度分别为11和18μgml-1，这表明1和2的毒性太大，无法进一步评估作为新的抗菌药物。稳定的同位素标记实验显示1的吡咯烷基源自鸟氨酸，2的哌啶基源自赖氨酸。蛋白质假单胞菌乙酰转移酶（PpATase）参与单乙酰间苯三酚和DAPG的生物合成。没有检测到1或2的旋光性，可能的原因是通过研究PpATase是否可以催化1和2中的吡咯烷基/哌啶基的立体非特异性引入来研究的，除非可以使PpATase经受对于主要的构象变化，该酶不能参与该反应。但是，PpATase是