Pyochelin is a siderophore common to Pseudomonas aeruginosa and several other pathogenic bacteria. A pyochelin functionalized at the N3â²â² position with a propyl-amine extension was previously synthesized. In the present work we proved that this analog binds FptA, the pyochelin outer membrane receptor, and transports iron(III) efficiently into bacteria. This functionalized pyochelin seemed to be a good candidate for antibiotic vectorization in the framework of a Trojan horse prodrug strategy. In this context, conjugates between pyochelin and three fluoroquinolones (norfloxacin, ciprofloxacin and N-desmethyl-ofloxacin) were synthesized with a spacer arm that was either stable or hydrolyzable in vivo. Some pyochelinâfluoroquinolone conjugates had antibacterial activities in growth inhibition experiments on several P. aeruginosa strains. However, these activities were weaker than those of the antibiotic alone. These properties appeared to be related to both the solubility and bioavailability of conjugates and to the stability of the spacer arm used.
吡咯菌素是一种常见于
铜绿假单胞菌和其他几种致病菌的
铁载体。先前合成了一种在N3″位点功能化的
吡咯菌素,其末端连接了一个
丙胺基团。在本研究中,我们证实这种类似物能够与
吡咯菌素的外膜受体FptA结合,并高效地将
铁(III)转运至细菌内部。这种功能化的
吡咯菌素似乎是抗生素载体化的良好候选药物,适用于特洛伊木马前药策略。在此背景下,通过稳定的或可在体内
水解的接头臂,将
吡咯菌素与三种
氟喹诺
酮类抗生素(
诺氟沙星、
环丙沙星和N-脱甲基
氧氟沙星)合成了共轭物。某些
吡咯菌素-
氟喹诺酮共轭物在一些
铜绿假单胞菌菌株的生长抑制实验中展现出了抗菌活性。然而,这些活性弱于单一抗生素。这些特性似乎与共轭物的溶解性和
生物利用度以及所用接头臂的稳定性有关。