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On the basis of our previously discovered triazole antifungal lead compounds, heterocycle-benzene bioisosteric replacement was used to improve their pharmacokinetic profile. The designed new triazole derivatives have good antifungal activity toward a wide range of pathogenic fungi. Their binding mode with the target enzyme was clarified by molecular docking. The MIC value of the highly potent compound 8f against Candida albicans, Candida tropicalis, and Cryptococcus neoformans is 0.016 μg/mL, 0.004 μg/mL, and 0.016 μg/mL, respectively. Moreover, preliminary pharmacokinetic studies revealed that it showed improved oral absorption as compared to the lead compound iodiconazole and deserved for further evaluations., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

The incidence of invasive fungal infections and resistance to antifungal agents is increasing dramatically. It is highly desirable to develop novel azoles with improved biological profiles. The structure-activity relationship (SAR) of the N-substitutions was investigated in this study. In vitro antifungal activities revealed that sterically large groups were not favored for the N-substitutions. The removal of the N-substitutions had little effect on the antifungal activity. Two compounds with free amine group (i.e.9a and 10a) showed excellent activity with broad antifungal spectrum. The SAR results were supported by molecular docking and the N-substitutions were found to be important for the conformation of the side chains. The SAR and binding mode of the azoles are useful for further lead optimization., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

The incidence of life-threatening fungal infections is increasing dramatically. In an attempt to develop novel antifungal agents, our previously synthesized phenoxyalkylpiperazine triazole derivatives were used as lead structures for further optimization. By means of structure-based bioisosterism, triazolone was used as a new bioisostere of oxygen atom. This type of bioisosteric replacement can improve the water solubility without loss of hydrogen-bonding interaction with the target enzyme. A series of triazolone-containing triazoles were rationally designed and synthesized. As compared with fluconazole, several compounds showed higher antifungal activity with broader spectrum, suggesting their potential for further evaluations., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

The incidence of invasive fungal infections and associated mortality is increasing dramatically. Although azoles are first-line antifungal agents, cross-resistance and hepatic toxicity are their two major limitations. The discovery of novel non-azole lead compounds will be helpful to overcome these problems. On the basis of our previously reported benzopyran non-azole CYP51 inhibitor, scaffold hopping was used to design structurally diverse new compounds and expand the structure-activity relationships of the lead structure. Five kinds of scaffolds, namely benzimidazole, benzoxazole, benzothiazole, quinazolin-4-one and carboline, were chosen for synthesis. In vitro antifungal activity data and results from molecular docking revealed that the scaffold was important for the antifungal activity. Several compounds showed potent activity against both standard and clinically resistant fungal pathogens, suggesting that they can serve as a good starting point for the discovery of novel antifungal agents., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

In continuation of our work on azole antifungal agents, a series of new conformationally restricted triazole derivatives possessing benzylpiperidin-4-yl methyl amino side chains were designed and synthesized. All the new azoles showed moderate to excellent in vitro antifungal activity against most of the tested pathogenic fungi. Several compounds (such as 12e, 12f, 12h and 12n) showed higher antifungal activity against Candida albicans than fluconazole. Moreover, compounds 12g-i also showed good activity against Aspergillus fumigatus with their MIC80 on the level of 1 μg/mL. Flexible molecular docking was used to analyze the binding mode of the designed compounds. They interact with CACYP51 through hydrophobic and van der Waals interactions., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

In an attempt to find novel azole antifungal agents with improved activity and broader spectrum, computer modeling was used to design a series of new azoles with piperidin-4-one O-substituted oxime side chains. Molecular docking studies revealed that they formed hydrophobic and hydrogen-bonding interactions with lanosterol 14alpha-demethylase of Candida albicans (CACYP51). In vitro antifungal assay indicates that most of the synthesized compounds showed good activity against tested fungal pathogens. In comparison with fluconazole, itraconazole and voriconazole, several compounds (such as 10c, 10e, and 10i) show more potent antifungal activity and broader spectrum, suggesting that they are promising leads for the development of novel antifungal agents., (2010. Published by Elsevier Ltd.)

Lanosterol 14alpha-demethylase (CYP51) is an important target for antifungal drugs. An improved three-dimensional model of CYP51 from Candida albicans (CACYP51) was constructed by ligand-supported homology modeling and molecular dynamics simulations. The accuracy of the constructed model was evaluated by its performance in a small-scale virtual screen. The results show that known CYP51 inhibitors were efficiently discriminated by the model, and it performed better than our previous CACYP51 model. The active site of CACYP51 was characterized by multiple copy simultaneous search (MCSS) calculations. On the basis of the MCSS results, a series of novel azoles were designed and synthesized, and they showed good in vitro antifungal activity with a broad spectrum. The MIC(80) value of four of these compounds against C. albicans is 0.001 microg mL(-1), indicating that they are promising leads for the discovery of novel antifungal agents.

Lanosterol 14alpha-demethylase (CYP51) is an essential enzyme in the fungal life cycle and also an important target for the antifungal drug development. Based on the multiple sequence alignments of CYP51 family, an evolutionary tree of the CYP51 family was constructed by the evolutionary trace (ET) method. The identified trace residues could provide a reliable and rational guide to the design of CYP51 mutations and give more information about the detailed mechanism of substrate (drug) recognition and binding. The reliability of ET analysis to identify residues of functional importance was validated by the reported site-directed mutagenesis studies of CYP51s. Several residues in the active site were also validated by our mutagenesis studies. Mapping the identified trace residues onto the active site of the modeled structure of Candida albicans CYP51 (CACYP51) may provide useful information for the design of novel antifungal agents.

A series of new triazole derivatives were designed and synthesized on the basis of the active site of lanosterol 14alpha-demethylase from Candida albicans (CACYP51). 2-(2,4-Difluorophenyl)-3-(methyl-(3-phenoxyalkyl)amino)-1-(1H-1,2,4-triazol-1-yl)propan-2-ols show excellent in-vitro activity against most of the tested pathogenic fungi. The MIC(80) value of compound 8a against Candida albicans is 0.01 microM, which provides a good starting template for further structural optimization. The binding modes of the designed compounds were investigated by flexible molecular docking. The compounds interacted with CACYP51 through hydrophobic, van-der-Waals, and hydrogen-bonding interactions.

On the basis of the active site of lanosterol 14alpha-demethylase from Candida albicans (CACYP51), a series of new azoles were designed and synthesized. All the new azoles show excellent in vitro activity against most of the tested pathogenic fungi, which represent a class of promising leads for the development of novel antifungal agents. The MIC(80) value of compounds 8c, 8i and 8n against C. albicans is 0.001 microg/mL, indicating that these compounds are more potent than fluconazole, itraconazole and voriconazole. Flexible molecular docking was used to analyze the structure-activity relationships (SARs) of the compounds. The designed compounds interact with CACYP51 through hydrophobic, van der Waals and hydrogen-bonding interactions.

In response to the urgent need for novel antifungal agents with improved activity and broader spectrum, computer modeling was used to rational design novel antifungal azoles. On the basis of the active site of lanosterol 14alpha-demethylase from Candida albicans (CACYP51), a series of new azoles with substituted-phenoxypropyl piperazine side chains were rational designed and synthesized. In vitro antifungal activity assay indicates that the new azoles show good activity against most of the tested pathogenic fungi. Interestingly, the designed compounds are also active against an azole-resistant clinical strain. Compared to fluconazole and itraconazole, several compounds (such as 12i, 12j and 12n) show higher antifungal activity and broader spectrum, which are promising leads for the development of novel antifungal agents.

Cryptococcus neoformans is one of the most important causes of life-threatening fungal infections in immunocompromised patients. Lanosterol 14 alpha-demethylase (CYP51) is the target of azole antifungal agents. This study describes, for the first time, the 3-dimensional model of CYP51 from Cryptococcus neoformans (CnCYP51). The model was further refined by energy minimization and molecular-dynamics simulations. The active site of CnCYP51 was well characterized by multiple-copy simultaneous-search calculations, and four functional regions important for rational drug design were identified. The mode of binding of the natural substrate and azole antifungal agents with CnCYP51 was identified by flexible molecular docking. A G484S substitution mechanism for azole resistance in CnCYP51, which might be important for the conformation of the heme environment, is suggested.

A series of new antifungal triazole derivatives with phenylacetamide side chain were rational designed and synthesized on the basis of the structural information of lanosterol 14-demethylase (CYP51). In vitro antifungal activity assay indicated that several compounds showed higher activity than fluconazole. Especially, compound 8h showed excellent inhibitory activity against Candida albicans and Cryptococcus neoformans (MIC = 0.0156 lg ⁄ mL), suggesting that it is a promising lead for the development of novel antifungal agents. The binding mode of compound 8h was investigated by flexible molecular docking. It interacted with CACYP51 through hydrophobic and van der Waals interactions. [ABSTRACT FROM AUTHOR]

Abstract: N-myristoyltransferase (NMT) has been a promising new target for the design of novel antifungal agents with new mode of action. A series of benzoxazole and indole derivatives were designed and synthesized as isosteric analogues of benzoheterocyclic NMT Inhibitors. In vitro antifungal assay indicated that the benzoxazole derivatives were far more potent than the indoles. Molecular docking studies revealed that the hydrogen bonding interaction between the benzoheterocyclic core and NMT might be essential in the orientation of the inhibitor to a proper position. The antifungal activity of benzoxazole derivative 8f was comparable or superior to that of fluconazole, which can serve as a good starting point for further studies of structural diversity of the benzoheterocyclic NMT inhibitors. [ABSTRACT FROM AUTHOR]