Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 06100, Ankara, Turkey.
Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Microbiology, 06100, Ankara, Turkey.
Eur J Med Chem. 2019 Oct 1;179:634-648. doi: 10.1016/j.ejmech.2019.06.083. Epub 2019 Jun 29.
Systemic candidiasis is a rampant bloodstream infection of Candida spp. and C. albicans is the major pathogen isolated from infected humans. Azoles, the most common class of antifungals which suffer from increasing resistance, and especially intrinsically resistant non-albicans Candida (NAC) species, act by inhibiting fungal lanosterol 14α-demethylase (CYP51). In this study we identified a number of azole compounds in 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol/ethanone oxime ester structure through virtual screening using consensus scoring approach, synthesized and tested them for their antifungal properties. We reached several hits with potent activity against azole-susceptible and azole-resistant Candida spp. as well as biofilms of C. albicans. 5i's minimum inhibitor concentration (MIC) was 0.125 μg/ml against C. albicans, 0.5 μg/ml against C. krusei and 1 μg/ml against azole-resistant C. tropicalis isolate. Considering the MIC values of fluconazole against these fungi (0.5, 32 and 512 μg/ml, respectively), 5i emerged as a highly potent derivative. The minimum biofilm inhibitor concentration (MBIC) of 5c, 5j, and 5p were 0.5 μg/ml (and 5i was 2 μg/ml) against C. albicans biofilms, lower than that of amphotericin B (4 μg/ml), a first-line antifungal with antibiofilm activity. In addition, the active compounds showed neglectable toxicity to human monocytic cell line. We further analyzed the docking poses of the active compounds in C. albicans CYP51 (CACYP51) homology model catalytic site and identified molecular interactions in agreement with those of known azoles with fungal CYP51s and mutagenesis studies of CACYP51. We observed the stability of CACYP51 in complex with 5i in molecular dynamics simulations.
系统性念珠菌病是一种猖獗的念珠菌属血流感染，而白色念珠菌是从感染人类中分离出来的主要病原体。唑类药物是最常见的一类抗真菌药物，但它们的耐药性日益增加，尤其是固有耐药的非白念珠菌（NAC）物种，通过抑制真菌角鲨烯 14α-去甲基酶（CYP51）发挥作用。在这项研究中，我们通过共识评分方法的虚拟筛选，从 1-(2,4-二氯苯基）-2-(1H-咪唑-1-基）乙醇/乙酮肟酯结构中鉴定出了一些唑类化合物，合成并测试了它们的抗真菌特性。我们得到了一些具有强效活性的化合物，可对抗唑类敏感和唑类耐药的念珠菌属以及白色念珠菌的生物膜。化合物 5i 对白色念珠菌的最小抑菌浓度（MIC）为 0.125μg/ml，对克柔念珠菌的 MIC 为 0.5μg/ml，对唑类耐药的热带念珠菌分离株的 MIC 为 1μg/ml。考虑到氟康唑对这些真菌的 MIC 值（分别为 0.5、32 和 512μg/ml），5i 是一种非常有效的衍生物。化合物 5c、5j 和 5p 对白色念珠菌生物膜的最低抑菌浓度（MBIC）分别为 0.5μg/ml（5i 为 2μg/ml），低于两性霉素 B（4μg/ml），两性霉素 B是一种具有抗生物膜活性的一线抗真菌药物。此外，活性化合物对人单核细胞系的毒性可以忽略不计。我们进一步分析了活性化合物在白色念珠菌 CYP51（CACYP51）同源模型催化位点的对接构象，并确定了与已知唑类药物与真菌 CYP51 以及 CACYP51 突变研究一致的分子相互作用。我们在分子动力学模拟中观察到 CACYP51 与 5i 复合物的稳定性。
