Synthesis of Kalasinamide, a Putative Plant Defense Phototoxin
作者:Michael N. Gandy、Matthew J. Piggott
DOI:10.1021/np070582z
日期:2008.5.1
The first total synthesis of the azaanthracene kalasinamide (1) is described, and the discrepancy in the reported (13)C NMR data and melting points for the natural product from two different sources is resolved. Kalasinamide is prone to autosensitized photooxidation, in solution and in the solid state, to give the corresponding quinone, marcanine A (8). This transformation may be representative of a novel and more general step in the biosynthesis of (aza)anthraquinones. Through its ability to generate toxic singlet oxygen, kalasinamide may serve a protective role, defending the plant against predation and the invasion of microbial pathogens, following mechanical insult.
Alkyltriphenylphosphonium turns naphthoquinoneimidazoles into potent membrane depolarizers against <i>mycobacteria</i>
作者:Kevin Timothy Fridianto、Gregory Adrian Gunawan、Kiel Hards、Jickky Palmae Sarathy、Gregory M. Cook、Thomas Dick、Mei-Lin Go、Yulin Lam
DOI:10.1039/d2md00251e
日期:——
bioenergetics is an attractive therapeutic target for anti-tuberculosis drug discovery. Building upon our work on antimycobacterial dioxonaphthoimidazoliums that were activated by a proximal positive charge and generated reactive oxygen species upon reduction by TypeIINADHdehydrogenase, we herein studied the effect of a distal positive charge on the antimycobacterialactivity of naphthoquinoneimidazoles by
由于其在能量产生和细菌活力中的核心作用,分枝杆菌生物能学是抗结核药物发现的有吸引力的治疗靶点。基于我们对由近端正电荷激活并在 II 型 NADH 脱氢酶还原时产生活性氧的抗分枝杆菌二氧萘并咪唑的研究,我们在此研究了远端正电荷通过掺入三烷基膦阳离子对萘醌咪唑的抗分枝杆菌活性的影响。结构-活性关系研究证实了接头长度的效力增强特性。抗结核分枝杆菌最活跃的化合物H37Rv 在低微摩尔范围内显示出良好的选择性指数 (SI = 34) 和强杀菌活性,这是通过细菌膜快速去极化导致细胞内 ATP 耗尽而发生的。通过这项工作,我们展示了通过重新定位正电荷来改变支架的作用方式,同时保持其出色的抗菌活性和选择性。