Cardoso João M S, Guerreiro Soraia I, Lourenço Andreia, Alves Marta M, Montemor M Fátima, Mira Nuno P, Leitão Jorge H, Carvalho M Fernanda N N
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal.
iBB-Institute for Bioengineering and Biosciences and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal.
PLoS One. 2017 May 9;12(5):e0177355. doi: 10.1371/journal.pone.0177355. eCollection 2017.
The present work follows a previous report describing the antibacterial activity of silver camphorimine complexes of general formula [Ag(NO3)L]. The synthesis and demonstration of the antifungal and antibacterial activity of three novel [Ag(NO3)L] complexes (named 1, 2 and 3) is herein demonstrated. This work also shows for the first time that the previously studied complexes (named 4 to 8) also exert antifungal activity. The antibacterial activity of complexes was evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia contaminans and Escherichia coli strains, while antifungal activity was tested against the Candida species C. albicans, C. glabrata, C. parapsilosis and C. tropicalis. The antimicrobial activity of the complexes ranged from very high (complex 4) to moderate (complex 6) or low (complex 8), depending on the structural and electronic characteristics of the camphorimine ligands. Notably, the highest antibacterial and anti-Candida activities do not coincide in the same complex and in some cases they were even opposite, as is the case of complex 4 which exhibits a high anti-bacterial and low antifungal activity. These distinct results suggest that the complexes may have different mechanisms against prokaryotic and eukaryotic cells. The antifungal activity of the Ag(I) camphorimine complexes (in particular of complex 1) was found to be very high (MIC = 2 μg/mL) against C. parapsilosis, being also registered a prominent activity against C. tropicalis and C. glabrata. None of the tested compounds inhibited C. albicans growth, being this attributed to the ability of these yeast cells to mediate the formation of less toxic Ag nanoparticles, as confirmed by Scanning Electron Microscopy images. The high antibacterial and anti-Candida activities of the here studied camphorimine complexes, especially of complexes 1 and 7, suggests a potential therapeutic application for these compounds.
本研究继先前一篇报道之后展开,该报道描述了通式为[Ag(NO₃)L]的银樟脑亚胺配合物的抗菌活性。本文展示了三种新型[Ag(NO₃)L]配合物(命名为1、2和3)的抗真菌和抗菌活性的合成及论证。这项工作还首次表明,先前研究的配合物(命名为4至8)也具有抗真菌活性。针对金黄色葡萄球菌、铜绿假单胞菌、污染伯克霍尔德菌和大肠杆菌菌株评估了配合物的抗菌活性,同时针对白色念珠菌、光滑念珠菌、近平滑念珠菌和热带念珠菌测试了抗真菌活性。配合物的抗菌活性范围从非常高(配合物4)到中等(配合物6)或低(配合物8),这取决于樟脑亚胺配体的结构和电子特性。值得注意的是,最高的抗菌和抗念珠菌活性并不出现在同一配合物中,在某些情况下甚至相反,例如配合物4表现出高抗菌活性和低抗真菌活性。这些不同的结果表明,配合物针对原核细胞和真核细胞可能具有不同的作用机制。发现Ag(I)樟脑亚胺配合物(特别是配合物1)对近平滑念珠菌的抗真菌活性非常高(MIC = 2 μg/mL),对热带念珠菌和光滑念珠菌也表现出显著活性。所测试的化合物均未抑制白色念珠菌的生长,这归因于这些酵母细胞介导形成毒性较小的银纳米颗粒的能力,扫描电子显微镜图像证实了这一点。本文研究的樟脑亚胺配合物,尤其是配合物1和7的高抗菌和抗念珠菌活性,表明这些化合物具有潜在的治疗应用价值。