Sawa Ryuichi, Kubota Yumiko, Umekita Maya, Hatano Masaki, Hayashi Chigusa, Igarashi Masayuki
Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.
J Antibiot (Tokyo). 2017 Nov 15. doi: 10.1038/ja.2017.140.
Drug-resistant bacteria are still emerging, and screening of new skeletal antibiotics is important. During our continuous screening for antimicrobial agents, we discovered a new antimicrobial, named quadoctomycin, from solid culture of Streptomyces sp. MM168-141F8. The substance was purified by solvent extraction, silica gel chromatography and HPLC. Structural elucidation of quadoctomycin was performed by MS and NMR analyses and chemical degradation. Quadoctomycin possesses a 48-membered polyol macrolide skeleton in which an α-D-mannoside is connected to C-22 by an O-glycosidic linkage. The structure of quadoctomycin was found to be related to that of monazomycin A based on the analyses of NMR spectra in the same solvent (pyridine-d). Quadoctomycin showed potent antibacterial activity against Staphylococcus aureus, including methicillin-resistant S. aureus, and other Gram-positive pathogenic bacteria such as Enterococcus faecalis and E. faecium (including drug-resistant strains), but did not show activity toward Gram-negative bacteria or Candida albicans.The Journal of Antibiotics advance online publication 15 November 2017; doi:10.1038/ja.2017.140.
耐药细菌仍在不断出现，因此筛选新型骨骼抗生素非常重要。在我们持续筛选抗菌剂的过程中，我们从链霉菌属MM168 - 141F8的固体培养物中发现了一种名为夸多霉素的新型抗菌剂。该物质通过溶剂萃取、硅胶柱色谱和高效液相色谱进行纯化。通过质谱、核磁共振分析和化学降解对夸多霉素进行了结构解析。夸多霉素具有一个48元的多元醇大环内酯骨架，其中一个α - D - 甘露糖苷通过O - 糖苷键连接到C - 22位。基于在相同溶剂（吡啶 - d）中的核磁共振光谱分析，发现夸多霉素的结构与莫那霉素A的结构相关。夸多霉素对金黄色葡萄球菌（包括耐甲氧西林金黄色葡萄球菌）以及其他革兰氏阳性病原菌如粪肠球菌和屎肠球菌（包括耐药菌株）显示出强大的抗菌活性，但对革兰氏阴性菌或白色念珠菌没有活性。《抗生素杂志》2017年11月15日在线优先发表；doi:10.1038/ja.2017.140 。
