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In the last few years resistance to azole fungicides has appeared in infected crops and has become more serious. Our aim was to analyse the reasons underlying the progressive decrease in the effectiveness of azole fungicides in controlling Magnaporthe grisea, the causal agent of rice blast. Forty-nine isolates of M. grisea were isolated from Hubei, Hunan, Jiangsu and Heilongjiang provinces in China. Their sensitivity to five sterol demethylation inhibitors, such as diniconazole, tebuconazole, triadimenol, triadimefon and propiconazole was measured. Three insensitive isolates (HM2, CY3 and CY6) and three hypersensitive isolates (CY8, YA10 and 101301) were characterised to elucidate the sensitivity mechanism to triazoles. Through a comparison of M13 fingerprinting, CYP51 sequences and expression, the results indicated that the genetic background of M. grisea isolates and CYP51 expression are conserved. However, the substitution of S312L in SRS4 of M. grisea CYP51F2 may contribute to the sensitivity difference of M. grisea to triazoles. [ABSTRACT FROM AUTHOR]

Azole-based antifungal agents constitute one of the important classes of antifungal drugs. Hence, in the present work, 12 new benzimidazole-thiazole derivatives 3a-3l were synthesized to evaluate their anticandidal activity against C. albicans, C. glabrata, C. krusei, and C. parapsilopsis. The structures of the newly synthesized compounds 3a-3l were confirmed by IR, ¹H-NMR, 13C-NMR, and ESI-MS spectroscopic methods. ADME parameters of synthesized compounds 3a-3l were predicted by an in-slico study and it was determined that all synthesized compounds may have a good pharmacokinetic profile. In the anticandidal activity studies, compounds 3c and 3d were found to be the most active compounds against all Candida species. In addition, cytoxicity studies showed that these compounds are nontoxic with a IC50 value higher than 500 μg/mL. The effect of compounds 3c and 3d on the ergosterol level of C. albicans was determined by an LC-MS-MS method. It was observed that both compounds cause a decrease in the ergosterol level. A molecular docking study including binding modes of 3c to lanosterol 14α-demethylase (CYP51), a key enzyme in ergosterol biosynthesis, was performed to elucidate the mechanism of the antifungal action. The docking studies revealed that there is a strong interaction between CYP51 and the most active compound 3c. [ABSTRACT FROM AUTHOR]

Cercospora leaf spot (CLS) caused by Cercospora beticola occurs annually in Serbia causing severe yield losses of sugar beet, which requires intensive use of fungicides. In recent years we have observed unsatisfactory control of CLS originating from northwestern Serbia. Frequency of C. beticola populations resistant to Quinone outside inhibitors (QoI) was 81% (51/63 isolates), 98% (62/63) to sterol-demethylation inbibitors (DMI) and 54% (34/63) to methyl-2-benzimidazole carbamate fungicides (MBC). The genetic basis underlying the resistance was tested by characterizing the cob, CYP51 and ß-tubulin genes, associated with resistance to QoI, DMI and MBC fungicides, respectively. Isolates that were resistant to QoI fungicides had the G143A mutation in the cob gene. Characterization of the CYP51 gene revealed seven diverse haplotypes; however, no correlation with sensitivity or resistance to DMI fungicides could be identified. Resistance to MBC fungicides was associated with the presence of the E198A mutation in the ß-tubulin gene of all resistant isolates. From a total of 63 isolates originating from sugar beet fields of northwestern Serbia, 62 isolates showed resistance to multiple modes of action. Three multi-resistant phenotypes were identified: MR1 ( N = 29) - resistant to QoI and DMI fungicides (QoI-R and DMI-R) but sensitive to MBC fungicides (MBC-S); MR2 ( N = 11, QoI-S, DMI-R and MBC-R); and MR3 ( N = 22), resistant to all three groups of fungicides (QoI-R, DMI-R and MBC-R). This is the first report of C. beticola resistance to QoI fungicides in Serbia. This study revealed development of multi-resistance of C. beticola isolates to MBC, DMI and QoI fungicides, which represents the first record of this phenomenon in C. beticola populations. [ABSTRACT FROM AUTHOR]

Reconstitution of a selective demethylation system for lanosterol is desperately needed for more efficient synthesis of steroidal drugs. Sterol 14α-demethylase cytochrome P450 (CYP51) has been confirmed to catalyze sterol 14α-demethylation, an essential reaction in sterol biosynthesis. Herein, a putative CYP51 gene ( Rt CYP51) was mined from the complete genome sequence of Rhodococcus triatomae BKS 15-14. Its amino acid sequence showed 25–68% identity to other sterol 14α-demethylases, and contained a novel alanine-rich sequence at the C-terminus. Heterologous expression of the Rt CYP51 gene in Escherichia coli ( E. coli ) yielded a ∼54 kDa recombination protein that exhibited a typical reduced CO-difference spectrum and a dissociation constant ( K d ) of 2.93 μM for lanosterol. Furthermore, three exogenous electron donor systems, including Fdx-FdR ( Acinetobacter sp.OC4 ferredoxin and ferredoxin reductase), Fld-FdR2 ( E. coli flavodoxin and flavodoxin reductase) and Nf FdR ( Nocardia farcinica iron-sulfur containing NADPH-P450 reductase) were selected for coupling the electron-transfer from the coenzyme to Rt CYP51. Fdx-FdR was found to be the most efficient electron donor and was also confirmed to support the lanosterol demethylation activity of Rt CYP51 in vitro . Under the optimum molar ratio of Rt CYP51/FdR/Fdx (1:2:10), Rt CYP51 exhibited a relatively high turnover number of 0.63 min −1 (nmol metabolized lanosterol/min/nmol Rt CYP51), compared with known bacterial CYP51s. [ABSTRACT FROM AUTHOR]

Azole resistance in human fungal pathogens has increased over the past twenty years, especially in immunocompromised patients. Similarities between medical and agricultural azoles, and extensive azole (14α-demethylase inhibitor, DMI) use in crop protection, prompted speculation that resistance in patients with aspergillosis originated in the environment. Aspergillus species, and especially Aspergillus fumigatus, are the largest cause of patient deaths from fungi. Azole levels in soils following crop spraying, and differences in sensitivity between medical and agricultural azoles (DMIs), indicate weaker selection in cropping systems than in patients receiving azole therapy. Most fungi have just one CYP51 paralogue (isozyme CYP51B), but in Aspergillus sp. mutations conferring azole resistance are largely confined to a second paralogue, CYP51A. Binding within the active centre is similar for medical and agricultural azoles but differences elsewhere between the two paralogues may ensure selection depends on the DMI used on crops. Two imidazoles, imazalil and prochloraz, have been widely used since the early 1970s, yet unlike triazoles they have not been linked to resistance in patients. Evidence that DMIs are the origin, or increase the frequency, of azole resistance in human fungal pathogens is lacking. Limiting DMI use would have serious impacts on disease control in many crops, and remove key tools in anti-resistance strategies. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

To further enhance the anti- Aspergillus efficacy of our previously discovered antifungal lead compounds ( 1 ), a series of aromatic heterocyclic derivatives were designed, synthesized and evaluated for in vitro antifungal activity. Many of the target compounds showed good inhibitory activity against Candida albicans and Cryptococcus neoformans . In particular, the isoxazole nuclei were more suited for improving the activity against Aspergillus spp . Among these compounds, 2-F substituted analogues 23g and 23h displayed the most remarkable in vitro activity against Candida spp. , C. neoformans , A. fumigatus and fluconazole-resistant C.alb. strains, which is superior or comparable to the activity of the reference drugs fluconazole and voriconazole. Notably, the compounds 23g and 23h exhibited low inhibition profiles for various isoforms of human cytochrome P450 and excellent blood plasma stability. [ABSTRACT FROM AUTHOR]

Septoria tritici blotch (STB) caused by the fungal pathogen Zymoseptoria tritici is a global threat to sustainable wheat production. Applications of fungicide against STB are regarded as an essential means to minimise yield losses, however, fungicide resistance is developing and affecting fungicide efficacy greatly. Only a few fungicide classes are available for STB control. DMI fungicides are seen as the main group, but increasing problems with resistance is challenging their use. In 2015 and 2016, field trials were conducted testing fungicide spray strategies using one, two or three applications, alternations, mixtures of different DMIs and DMI mixed with other modes of action including a SDHI and a multi-site inhibitor. The strategies were tested for disease control, their impact on yield and their effect on resistance build-up, measured as CYP51 alterations responsible for decreased sensitivity and efficacy of DMIs. Strategies consisting of three treatments provided adequate control of STB and significant yield increases. The best results with regard to yield and control were attained by a diversified DMI strategy also including the SDHI boscalid and the multi-site inhibitor folpet. Spraying once or twice lowered selection yet compromised STB control and yield. CYP51 alteration I381V was the most predominated in all samples. Frequencies of alterations D134G, V136A and S524T increased significantly following applications with DMI fungicides. The more diversified a strategy, the less it selected for CYP51 alterations. EC 50 values for epoxiconazole showed a tendency to be higher post-treatment in 2015. The results presented in this study encourage the adoption of mixing and alternating fungicides into spray strategies to minimise the risk of resistance build-up and to prolong the effective life of fungicides. [ABSTRACT FROM AUTHOR]

While the orally-active azoles such as fluconazole and posaconazole are effective antifungal agents, they potently inhibit a broad range of off-target human cytochrome P450 enzymes (CYPs) leading to various safety issues (e.g., drug-drug interactions, liver, and reproductive toxicities). Recently we described the rationally-designed, antifungal agent VT-1161 that is more selective for fungal CYP51 than related human CYP enzymes such as CYP3A4. Herein, we describe the use of a homology model of Aspergillus fumigatus to design and optimize a novel series of highly selective, broad spectrum fungal CYP51 inhibitors. This series includes the oral antifungal VT-1598 that exhibits excellent potency against yeast, dermatophyte, and mold fungal pathogens. [ABSTRACT FROM AUTHOR]

Villosiclava virensis an ascomycete fungus (anamorph:Ustilaginoidea virens) recognized as one of the most economically important pathogens on rice in China that causes false smut disease. In our study, theV. virens cyp51gene encoding the target protein for fungicide resistant to tebuconazole was cloned. Sequencing showed that fungal mutant strains resistant to tebuconazole harboured the T409C mutation incyp51. A simple and rapid allele-specific PCR assay was developed to detect the T409C mutation. Among the isolates tested, a unique 391-bp fragment was amplified from resistant mutant strains with primer pair Uv137F1/Uv137DR, whereas no product was amplified from all sensitive isolates. Our study demonstrated that this allele-specific PCR assay is a rapid, simple and reliable method for identification ofV. virensmutants resistant to tebuconazole. [ABSTRACT FROM PUBLISHER]

Gallic acid (GA) is a polyphenol natural compound found in many medicinal plant species, including pomegranate rind (Punica granatum L.), and has been shown to have antiinflammatory and antibacterial properties. Pomegranate rind is used to treat bacterial and fungal pathogens in Uyghur and other systems of traditional medicine, but, surprisingly, the effects of GA on antifungal activity have not yet been reported. In this study, we aimed to investigate the inhibitory effects of GA on fungal strains both in vitro and in vivo. The minimal inhibitory concentration (MIC) was determined by the NCCLS (M38-A and M27-A2) standard method in vitro, and GA was found to have a broad spectrum of antifungal activity, with MICs for all the tested dermatophyte strains between 43.75 and 83.33 μg/mL. Gallic acid was also active against three Candida strains, with MICs between 12.5 and 100.0 μg/mL. The most sensitive Candida species was Candida albicans (MIC = 12.5 μg/mL), and the most sensitive filamentous species was Trichophyton rubrum (MIC = 43.75 μg/mL), which was comparable in potency to the control, fluconazole. The mechanism of action was investigated for inhibition of ergosterol biosynthesis using an HPLC-based assay and an enzyme linked immunosorbent assay. Gallic acid reduced the activity of sterol 14α-demethylase P450 (CYP51) and squalene epoxidase in the T. rubrum membrane, respectively. In vivo model demonstrated that intraperitoneal injection administration of GA (80 mg/kg d) significantly enhanced the cure rate in a mice infection model of systemic fungal infection. Overall, our results confirm the antifungal effects of GA and suggest a mechanism of action, suggesting that GA has the potential to be developed further as a natural antifungal agent for clinical use. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Although antifungal drug resistance in the human fungal pathogen Cryptococcus neoformans is relatively uncommon, fluconazole-resistant strains are problematic for preemptive treatment of cryptococcal antigenemia or during cryptococcal meningitis consolidation therapy. We analyzed activity of the experimental antifungal VT-1129 on 51 clinical Cryptococcus neoformans isolates previously screened for fluconazole resistance; with an emphasis on fluconazole dose-dependent (MIC 16-32 μg/ml) or resistant (MIC ≥ 64 μg/ml) isolates. Overall, the VT-1129 geometric mean MIC was 0.027 μg/ml. The VT-1129 MIC50 was 0.05 μg/ml and 0.25 μg/ml for dose-dependent (n = 27) and resistant isolates (n = 6), respectively. These data suggest VT-1129 shows potential for use against fluconazole-resistant Cryptococcus. [ABSTRACT FROM AUTHOR]

Azole antifungals are potent inhibitors of fungal lanosterol 14α demethylase (CYP51) and have been used for eradication of systemic candidiasis clinically. Herein we report the design, synthesis, and biological evaluation of a series of 1-phenyl/1-(4-chlorophenyl)-2-(1 H -imidazol-1-yl)ethanol esters. Many of these derivatives showed fungal growth inhibition at very low concentrations. Minimal inhibition concentration (MIC) value of 15 was 0.125 μg/mL against Candida albicans . Additionally, some of our compounds, such as 19 (MIC: 0.25 μg/mL), were potent against resistant C. glabrata , a fungal strain less susceptible to some first-line antifungal drugs. We confirmed their antifungal efficacy by antibiofilm test and their safety against human monocytes by cytotoxicity assay. To rationalize their mechanism of action, we performed computational analysis utilizing molecular docking and dynamics simulations on the C. albicans and C. glabrata CYP51 (CACYP51 and CGCYP51) homology models we built. Leu130 and T131 emerged as possible key residues for inhibition of CGCYP51 by 19 . [ABSTRACT FROM AUTHOR]

A total of 213Penicillium digitatumisolates with resistance to the fungicide imazalil (IMZ) originating from green moulded citrus fruit from several countries (South Africa, USA, Uruguay, Spain, Israel, Cyprus, Chile, Australia and Argentina) were tested for their Cyp51 IMZ-resistance group (R1 to R3) using a published multiplex PCR assay. As well, the level of resistance (measured as EC50values) was determined. Isolates from the USA showed the highest resistance group diversity (isolates belonged to R1, R2 and R3 groups) and lowest EC50values. The isolates from the other countries were all classified into the R3 group, except for Chile, which also contained R1 isolates. There was no correlation between the level of resistance of isolates and the resistance group genotype. In general, IMZ resistance was most commonly associated (88.3%) with the R3 group. This study is the first to investigate the distribution of IMZ resistance genotypes in P. digitatum populations from a broad international scale. [ABSTRACT FROM PUBLISHER]

Molecular docking is a valuable in silico technique for discovery/design of bioactive compounds. A current challenge within docking simulations is the incorporation of receptor flexibility. A useful strategy toward solving such problem would be the docking of a typical ligand into the multiple conformations of the target. In this study, a multifactor response surface model was constructed to estimate the AutoDock based binding free energy of fluconazole within multiple conformations of 14α-demethylase (CYP51) (cross docking) as a validated antifungal target. On the basis of developed models, individual and interactive effects of important experimental parameters on cross docking of fluconazole were elucidated. For this purpose, a set of high-resolution holo crystallographic structures from CYP51 of human pathogen Trypanosoma cruzi were retrieved to statistically model the binding mode and affinity of fluconazole. The changes of AutoDock binding free energy for the complexes of CYP51-fluconazole were elucidated with the simultaneous variations of six independent variables including grid size, grid spacing, number of genetic algorithm (GA) runs, maximum number of energy evaluations, torsion degrees for ligand and quaternion degrees for ligand. It was revealed that grid spacing (distance between adjacent grid points) and maximum number of energy evaluations were two significant model terms. It was also revealed that grid size, torsion degrees for ligand and quaternion degrees for ligand had insignificant effects on estimated binding energy while the effect of GA runs was non-significant. The interactive effect of “torsion degrees for ligand” with number of GA runs was found to be the significant factor. Other important interactive effects were the interaction of “number of GA runs” with “grid spacing” and “number of energy evaluations” with “grid size”. Furthermore; results of modeling studies within several CYP51 conformations exhibited that “number of GA runs” and “number of energy evaluations” were less sensitive to varied target conformations. [ABSTRACT FROM AUTHOR]

Previous work led to the rational design, synthesis and testing of novel antifungal triazole analogues bearing alkynyl-methoxyl side chains. Tests of in vitro antifungal activity showed Candida albicans SC5314 and Candida glabrata 537 gave MIC values of ≤0.125 μg/mL for most of the compounds. Among these, compounds 16 , 18 , and 29 displayed broad-spectrum antifungal activity against seven human pathogenic fungal species, two fluconazole-resistant C. albicans isolates and two multi-drug resistant Candida auris isolates. Moreover, 0.5 μg/mL of 16 , 18 , and 29 was more effective than 2 μg/mL of fluconazole at inhibiting fungal growth of the strains tested. The most active compound (16) completely inhibited the growth of C. albicans SC5314 at 16 μg/mL for 24 h, affected biofilm formation and destroyed the mature biofilm at 64 μg/mL. Several Saccharomyces cerevisiae strains, overexpressing recombinant Cyp51s or drug efflux pumps, indicated 16 , 18 , and 29 targeted Cyp51 without being significantly affected by a common active site mutation, but were susceptible to target overexpression and efflux by both MFS and ABC transporters. GC-MS analysis demonstrated that 16 , 18 , and 29 interfered with the C. albicans ergosterol biosynthesis pathway by inhibition at Cyp51. Molecular docking studies elucidated the binding modes of 18 with Cyp51. The compounds showed low cytotoxicity, low hemolytic activity and favorable ADMT properties. Importantly, compound 16 showed potent in vivo antifungal efficacy in the G. mellonella infection model. Taken together, this study presents more effective, broad-spectrum, low toxicity triazole analogues that can contribute to the development of novel antifungal agents and help overcome antifungal resistance. In this study, 27 novel triazole derivatives bearing alkynyl-methoxyl side chains were designed and synthesized based on our previous work. In vitro antifungal activity tests showed that most of the compounds exhibited excellent inhibition against Candida albicans SC5314 and Candida glabrata 537 (MIC ≤0.125 μg/mL). Among these, compounds 16 , 18 , and 29 displayed broad-spectrum antifungal activity and anti-drug-resistant fungal ability. Moreover, 16 inhibited the growth of C. albicans SC5314, reduced biofilm formation, and destroyed mature biofilm. Several Saccharomyces cerevisiae strains, overexpressing recombinant Cyp51s or drug efflux pumps, indicated these compounds targeted Cyp51 without being significantly affected by a common active site mutation but were susceptible to target overexpression and efflux by both MFS and ABC transporters. Importantly, 16 showed potent in vivo antifungal efficacy in the G. mellonella infection model. With more effective, broad-spectrum, anti-resistant, and low-toxicity triazole analogues that can contribute to the development of novel antifungal agents. [Display omitted] • Most of our novel triazole analogues showed excellent activity against C. albicans SC5314 and C. glabrata 537 (MICs ≤0.125 μg/mL). • Compounds 16 , 18 and 29 exhibited broad-spectrum antifungal activity against thirteen pathogenic fungi. • Compounds 16 reduced C. albicans biofilm formation and destroyed mature C. albicans biofilm. • Compounds 16 , 18 , and 29 targeted Cyp51 without being significantly affected by a common active site mutation, but were susceptible to target overexpression and efflux by both MFS and ABC transporters. • Compound 16 showed potent in vivo antifungal efficacy in the G. mellonella infection model. [ABSTRACT FROM AUTHOR]

Brassica juncea is a major oilseed, vegetable and condiment crop in the Indian subcontinent. Its yields are compromised by the aggressive broad host range Ascomycete Sclerotinia sclerotiorum, which causes Sclerotinia Stem Rot (SSR). The limited effectiveness of fungicides, the rapid development of resistance to fungicides, and the long-term viability of sclerotia in the soil are crucial bottlenecks in controlling the disease. The discovery of the uptake of environmental RNA by fungal pathogens has opened up avenues for exploiting Spray-Induced Gene Silencing (SIGS) as a tool for mitigating plant diseases. We studied the impact of SIGS-based knockdown of S. sclerotiorum SsOah1 (SS1G_08218) and SsCyp51 (SS1G_04805) , involved in virulence and fungal development, respectively, on two hosts- N. benthamiana and B. juncea. A knockdown of the two genes delayed disease initiation, reduced lesion development, and slowed disease progression within B. juncea. However, this silencing was concentration and host-dependent. Further, it also altered fungal hyphal morphology and growth, indicating its utility as a functional genomics tool. Our results identify SsCyp51 as a novel and viable target for SSR control along with SsOah1 and corroborate SIGS as a robust method for crop protection against broad-host-range fungal pathogens. • Spray-Induced Gene Silencing (SIGS) is an upcoming and robust methodology for Sclerotinia Stem Rot (SSR) control. • Foliar dsRNA application targeting SsOah1 and SsCyp51 delayed disease initiation and reduced disease lesion sizes. • SsCyp51 is implicated in Sclerotinia sclerotiorum development and growth. [ABSTRACT FROM AUTHOR]

Cytochromes P450 (CYP), enzymes involved in the metabolism of endogenous and xenobiotic substrates, provide an excellent model system to study how membrane proteins with unique functions have catalytically adapted through evolution. Molecular adaptation of deep-sea proteins to high hydrostatic pressure remains poorly understood. Herein, we have characterized recombinant cytochrome P450 sterol 14α-demethylase (CYP51), an essential enzyme of cholesterol biosynthesis, from an abyssal fish species, Coryphaenoides armatus. C. armatus CYP51 was heterologously expressed in Escherichia coli following N-terminal truncation and purified to homogeneity. Recombinant C. armatus CYP51 bound its sterol substrate lanosterol giving a Type I binding spectra (K D 15 μM) and catalyzed lanosterol 14α-demethylation turnover at 5.8 nmol/min/nmol P450. C. armatus CYP51 also bound the azole antifungals ketoconazole (K D 0.12 μM) and propiconazole (K D 0.54 μM) as determined by Type II absorbance spectra. Comparison of C. armatus CYP51 primary sequence and modeled structures with other CYP51s identified amino acid substitutions that may confer an ability to function under pressures of the deep sea and revealed heretofore undescribed internal cavities in human and other non-deep sea CYP51s. The functional significance of these cavities is not known. This paper is dedicated in memory of Michael Waterman and Tsuneo Omura, who as good friends and colleagues enriched our lives. They continue to inspire us. Deep sea fish cytochrome P450 51 (CYP51) and human CYP51 superimposed: The deep-sea fish has positionally unique amino acid substitutions (yellow), most on the protein surface, but with three interior substitutions apparently filling spaces where other CYP51 proteins have voids (supplementary cavities) (black). These amino acids preclude the voids from the deep-sea CYP51. [Display omitted] • Sterol demethylase cytochrome P450 51 (CYP51)was examined from a deep-sea fish. • The deep-sea CYP51 has positionally unique amino acids compared to other CYP51s. • These amino acid changes may contribute to evolutionary adaptation to pressure. • Comparisons also pointed to a previously unknown structural feature in other CYP51s. • The significance of this novel structural feature is unknown. [ABSTRACT FROM AUTHOR]

Anthracnose disease, caused by Colletotrichum truncatum , is a destructive fungal disease in soybean worldwide, and some demethylation inhibitor fungicides are used to manage it. In this study, the sensitivity of C. truncatum to difenoconazole was determined, and the risk for resistance development of C. truncatum to difenoconazole was also assessed. The results showed that the mean EC 50 value was 0.9313 μg/ml, and the frequency of sensitivity formed a unimodal distribution. Six stable mutants with a mutation frequency of 8.33 × 10 -5 were generated, and resistance factors ranged from 3.00 to 5.81 after 10 successive culture transfers. All mutants exhibited fitness penalties in reduced mycelial growth rate, sporulation, and pathogenicity, except for the Ct2-3-5 mutant. Positive cross-resistance was observed between difenoconazole and propiconazole but not between difenoconazole and prochloraz, pyraclostrobin, or fluazinam. One point mutation I463V in CYP51A was found in five resistant mutants. Surprisingly, the homologous I463V mutation has not been observed in other plant pathogens. CYP51A and CYP51B expression increased slightly in the resistant mutants as compared to wild-types when exposed to difenoconazole but not in the CtR61-2-3f and CtR61-2-4a mutants. In general, a new point mutation, I463V in CYP51A, could be associated with low resistance to difenoconazole in C. truncatum . In the greenhouse assay, control efficacy of difenoconazole on both parental isolates and the mutants increased in a dose-dependent manner. Collectively, the resistance risk of C. truncatum to difenoconazole is regarded to be low to moderate, suggesting that difenoconazole can still be reasonably used to control soybean anthracnose., Competing Interests: The author(s) declare no conflict of interest.

Inhibition of the Trypanosoma cruzi cysteine protease cruzain has been proposed as a therapeutic approach for the treatment of Chagas’ disease. Among the best-studied cruzain inhibitors to date is the vinylsulfone K777 (1), which has proven effective in animal models of Chagas’ disease. Recent structure–activity studies aimed at addressing potential liabilities of 1 have now produced analogues such as N-[(2S)-1-[[(E,3S)-1-(benzenesulfonyl)-5-phenylpent-1-en-3-yl]amino]-3-(4-methylphenyl)-1-oxopropan-2-yl]pyridine-4-carboxamide (4), which is trypanocidal at ten-fold lower concentrations than for 1. We now find that the trypanocidal activity of 4 derives primarily from the inhibition of T. cruzi 14-α-demethylase (TcCYP51), a cytochrome P450 enzyme involved in the biosynthesis of ergosterol in the parasite. Compound 4 also inhibits mammalian CYP isoforms but is trypanocidal at concentrations below those required to significantly inhibit mammalian CYPs in vitro. A chemical-proteomics approach employing an activity-based probe derived from 1 was used to identify mammalian cathepsin B as a potentially important off-target of 1 and 4. Computational docking studies and the evaluation of truncated analogues of 4 reveal structural determinants for TcCYP51 binding, information that will be useful in further optimization of this new class of inhibitors.

Pyrenophora teres f. sp. teres is the cause of net form of net blotch, an economically important foliar disease in barley (Hordeum vulgare). Net and spot forms of net blotch are widely controlled using site-specific systemic fungicides. Although resistance to succinate dehydrogenase inhibitors and quinone outside inhibitors has been addressed before in net blotches, mechanisms controlling demethylation inhibitor resistance have not yet been reported at the molecular level. Here we report the isolation of strains of net form of net blotch in Australia since 2013 resistant to a range of demethylase inhibitor fungicides. Cyp51A:KO103-A1, an allele with the mutation F489L, corresponding to the archetype F495I in Aspergillus fumigatus, was only present in resistant strains and was correlated with resistance factors to various demethylase inhibitors ranging from 1.1 for epoxiconazole to 31.7 for prochloraz. Structural in silico modelling of the sensitive and resistant CYP51A proteins docked with different demethylase inhibitor fungicides showed how the interaction of F489L within the heme cavity produced a localised constriction of the region adjacent to the docking site that is predicted to result in lower binding affinities. Resistant strains also displayed enhanced induced expression of the two Cyp51A paralogs and of Cyp51B genes. While Cyp51B was found to be constitutively expressed in the absence of fungicide, Cyp51A was only detected at extremely low levels. Under fungicide induction, expression of Cyp51B, Cyp51A2 and Cyp51A1 was shown to be 1.6-, 3- and 5.3-fold higher, respectively in the resistant isolate compared to the wild type. These increased levels of expression were not supported by changes in the promoters of any of the three genes. The implications of these findings on demethylase inhibitor activity will require current net blotch management strategies to be reconsidered in order to avoid the development of further resistance and preserve the lifespan of fungicides in use.

The Forkhead transcription factors FoxO1, FoxO3a, and FoxO4 play a prominent role in regulating cell survival and cell cycle. Whereas FOXO1 was shown to mediate insulin sensitivity and adipocyte differentiation, the role of the transcription factor FoxO4 in metabolism remains ill defined. To uncover the effects of FoxO4, we generated a cellular model of stable FoxO4 overexpression and subjected it to microarray-based gene expression profiling. While pathway analysis revealed a disruption of cholesterol biosynthesis gene expression, biochemical studies revealed an inhibition of cholesterol biosynthesis, which was coupled with decreased mRNA levels of lanosterol 14α demethylase (CYP51). FoxO4-mediated repression of CYP51 led to the accumulation of 24,25 dihydrolano­sterol (DHL), which independently and unlike lanosterol inhibited cholesterol biosynthesis. Furthermore, FoxO4-overexpressing cells accumulated lipid droplets and triacylglycerols and had an increase in basal glucose uptake. Recapitulation of these effects was obtained following treatment with CYP51 inhibitors, which also induce DHL buildup. Moreover, DHL but not lanosterol strongly stimulated liver X receptor α (LXRα) activity, suggesting that DHL and LXRα mediate the downstream effects initiated by FoxO4. Together, these studies suggest that FoxO4 acts on CYP51 to regulate the late steps of cholesterol biosynthesis.

This review will focus on two general approaches carried out at the Sandler Center, University of California, San Francisco, to address the challenge of developing new drugs for the treatment of Chagas disease. The first approach is target-based drug discovery, and two specific targets, cytochrome P450 CYP51 and cruzain (aka cruzipain), are discussed. A "proof of concept" molecule, the vinyl sulfone inhibitor K777, is now a clinical candidate. The preclinical assessment compliance for filing as an Investigational New Drug with the United States Food and Drug Administration (FDA) is presented, and an outline of potential clinical trials is given. The second approach to identifying new drug leads is parasite phenotypic screens in culture. The development of an assay allowing high throughput screening of Trypanosoma cruzi amastigotes in skeletal muscle cells is presented. This screen has the advantage of not requiring specific strains of parasites, so it could be used with field isolates, drug resistant strains or laboratory strains. It is optimized for robotic liquid handling and has been validated through a screen of a library of FDA-approved drugs identifying 65 hits.

Hypercholesterolaemia is a risk factor for CVD, which is a leading cause of death in industrialised societies. The biosynthetic pathways for cholesterol metabolism are well understood; however, the regulation of circulating cholesterol by diet is still not fully elucidated. The present study aimed to gain more comprehensive understanding of the relationship between circulating cholesterol levels and molecular effects in target tissues using the hamster model. Male golden Syrian hamsters were fed with chow or diets containing 36 % energy from fat with or without 1 % cholesteyramine (CA) as a modulator of circulating cholesterol levels for 35 d. It was revealed that the expression of lanosterol 14α-demethylase (CYP51) instead of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression was responsive to circulating cholesterol in hamsters fed hypercholesterolaemic diets. The high-fat diet increased circulating cholesterol and down-regulated CYP51, but not HMG-CoA reductase. The CA diet decreased cholesterol and increased CYP51 expression, but HMG-CoA reductase expression was not affected. The high-fat diet and CA diet altered the expression level of cholesterol, bile acids and lipid metabolism-associated genes (LDL receptor, cholesterol 7α-hydroxylase (CYP7A1), liver X receptor (LXR) α, and ATP-binding cassette subfamily G member 5/8 (ABCG5/8)) in the liver, which were significantly correlated with circulating cholesterol levels. Correlation analysis also showed that circulating cholesterol levels were regulated by LXR/retinoid X receptor and PPAR pathways in the liver. Using the hamster model, the present study provided additional molecular insights into the influence of circulating cholesterol on hepatic cholesterol metabolism pathways during hypercholesterolaemia.

Botrytis cinerea (B. cinerea) may cause severe decay in fruits and vegetables. In this paper, we found a food-borne compound ginsenoside CK (GCK) (from Ginseng) demonstrating excellent anti- B. cinerea activity and investigated its underlying inhibitory mechanism. The computational biology methods and bioactivity assays revealed that GCK markedly inhibited the bioactivity of sterol 14α-demethylase cytochrome P450 (CYP51) in B. cinerea with a competitive inhibitory mechanism (IC 50 = 14.45 μM). In vitro tests showed that GCK (64 × 10−3 g L−1) limited the mycelial growth of B. cinerea through inhibiting CYP51 activity by 85.92%. Notably, GCK treatment decreased the bioactivity of CYP51, thereby increasing cell membrane permeability that led to the death of B. cinerea. Moreover, GCK (64 × 10−3 g L−1) treatment reduced the decay of cherry tomatoes by 89.24% compared with those of blank control group. Our research revealed that the food-borne substance GCK could inhibit B. cinerea , prolonging the shelf life of cherry tomatoes. Thus, GCK has the potential to be applied in the preservation of fruits as an antifungal agent. [Display omitted] • GCK exhibited the excellent anti-CYP51 activity of Botrytis cinerea. • GCK influenced the catalytic activity of CYP51 as the competition inhibitory. • GCK hindered the growth of Botrytis cinerea by inhibiting CYP51. • The shelf life of tomato infection model could be prolonged by GCK. [ABSTRACT FROM AUTHOR]

Cytochrome P450 (P450, CYP) family 51 enzymes catalyze the 14α-demethylation of sterols, leading to critical products used for membranes and the production of steroids, as well as signaling molecules. In mammals, P450 51 catalyzes the 3-step, 6-electron oxidation of lanosterol to form (4β,5α)-4,4-dimethyl-cholestra-8,14,24-trien-3-ol (FF-MAS). P450 51A1 can also use 24,25-dihydrolanosterol (a natural substrate in the Kandutsch-Russell cholesterol pathway). 24,25-Dihydrolanosterol and the corresponding P450 51A1 reaction intermediates, the 14α-alcohol and -aldehyde derivatives of dihydrolanosterol, were synthesized to study the kinetic processivity of the overall 14α-demethylation reaction of human P450 51A1. A combination of steady-state kinetic parameters, steady-state binding constants, dissociation rates of P450-sterol complexes, and kinetic modeling of the time course of oxidation of a P450-dihydrolanosterol complex showed that the overall reaction is highly processive, with k off  rates of P450 51A1-dihydrolanosterol and the 14α-alcohol and 14α-aldehyde complexes being 1 to 2 orders of magnitude less than the forward rates of competing oxidations. epi-Dihydrolanosterol (the 3α-hydroxy analog) was as efficient as the common 3β-hydroxy isomer in the binding and formation of dihydro FF-MAS. The common lanosterol contaminant dihydroagnosterol was found to be a substrate of human P450 51A1, with roughly one-half the activity of dihydrolanosterol. Steady-state experiments with 14α-methyl deuterated dihydrolanosterol showed no kinetic isotope effect, indicating that C-14α C-H bond breaking is not rate-limiting in any of the individual steps. The high processivity of this reaction generates higher efficiency and also renders the reaction less sensitive to inhibitors., Competing Interests: Conflict of interest All of the authors declare that they have no conflict of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Chagas disease (CD) imposes social and economic burdens, yet the available treatments have limited efficacy in the disease's chronic phase and cause serious adverse effects. To address this challenge, target-based approaches are a possible strategy to develop new, safe, and active treatments for both phases of the disease., Areas Covered: This review delves into target-based approaches applied to CD drug discovery, emphasizing the studies from the last five years. We highlight the proteins cruzain (CZ), trypanothione reductase (TR), sterol 14 α-demethylase (CPY51), iron superoxide dismutase (Fe-SOD), proteasome, cytochrome b (Cyt b) , and cleavage and polyadenylation specificity factor 3 (CPSF3), chosen based on their biological and chemical validation as drug targets. For each, we discuss its biological relevance and validation as a target, currently related challenges, and the status of the most promising inhibitors., Expert Opinion: Target-based approaches toward developing potential CD therapeutics have yielded promising leads in recent years. We expect a significant advance in this field in the next decade, fueled by the new options for Trypanosoma cruzi genetic manipulation that arose in the past decade, combined with recent advances in computational chemistry and chemical biology.

CYP51 is an enzyme of sterol biosynthesis pathway present in animals, plants, protozoa and fungi. This enzyme is described as an important drug target that is still of interest. Therefore, in this work, we reviewed the structure and function of CYP51 and explored the molecular modeling approaches for the development of new antifungal and antiprotozoans that target this enzyme. Crystallographic structures of CYP51 of some organisms have already been described in the literature, which enable the construction of homology models of other organisms' enzymes and molecular docking studies of new ligands. The binding mode and interactions of some new series of azoles with antifungal or antiprotozoan activities has been studied and showed important residues of the active site. Molecular modeling is an important tool to be explored for the discovery and optimization of CYP51 inhibitors with better activities, pharmacokinetics, and toxicological profiles. [ABSTRACT FROM AUTHOR]

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Fungal infections have became a serious medical problem due to their high incidence and mortality. We describe the discovery and structure-activity relationships studies (SARs) of a series of novel biphenyl imidazole derivatives with excellent antifungal activities against Candida albicans and Cryptococcus neoformans . The most promising compounds 12f – g and 19a – b exhibited excellent activity with minimum inhibitory concentration (MIC) values in the range of 0.03125–2 μg/mL. Preliminary mechanism studies showed that the potent antifungal activity of compound 12g stemed from inhibition of CYP51 in Candida albicans . Furthermore, compounds 12g and 19b exhibited low inhibition profiles for various human cytochrome P450 isoforms. The SARs and binding mode established in this study will be useful for further lead optimization. [ABSTRACT FROM AUTHOR]

A series of compounds with benzothiazole and amide-imidazole scaffolds were designed and synthesized to combat the increasing incidence of drug-resistant fungal infections. The antifungal activity of these compounds was evaluated in vitro , and their structure-activity relationships (SARs) were evaluated. The synthesized compounds showed excellent inhibitory activity against Candida albicans and Cryptococcus neoformans . The most potent compounds 14o , 14p , and 14r exhibited potent activity, with minimum inhibitory concentration (MIC) values in the range of 0.125–2 μg/mL. Preliminary mechanism studies revealed that the compound 14p might act by inhibiting the CYP51 of Candida albicans . The SARs and binding mode established in this study are useful for further lead optimization. [ABSTRACT FROM AUTHOR]

Fungal pathogens continue to pose challenges to humans and plants despite efforts to control them. Two coumarins, robustic acid and thonningine-C isolated from Millettia thonningii, show promising activity against the fungus Candida albicans with minimum fungicidal concentration of 1.0 and 0.5 mg/mL, respectively. Molecular modelling against the putative bio-molecular target, lanosterol 14 -demethylase (CYP51), revealed a plausible binding mode for the active compounds, in which the hydroxyl group binds with a methionine backbone carboxylic group blocking access to the iron catalytic site. This binding disrupts the synthesis of several important sterols for the survival of fungi. [ABSTRACT FROM AUTHOR]

A number of new coumarin derivatives (CD) have been proposed at our research laboratory, from a molecular docking study, and we determine the ones that potentially would show antifungal activity. This is done by comparing the binding modes of the new CD with the active site of protein CYP51, which is experimentally known to be the biological target of one very important group of commercial antifungal agents currently employed (azolic antifungal drugs), such as Fluconazole (FLU). In this way, we could establish which of the new CD would bind in a similar way to the FLU binding mode to the active site of CYP51 and compare the relative interaction energies. Our computational study suggests that two of the proposed CD show ligand efficiencies and binding modes comparable to those of FLU, and thus that they would be suitable antifungal agents. [ABSTRACT FROM AUTHOR]

Pyrenophora teres f. sp. teres is the cause of net form of net blotch (NFNB), an economically important foliar disease in barley (Hordeum vulgare). Net and spot forms of net blotch are widely controlled using site-specific systemic fungicides. Although resistance to succinate dehydrogenase inhibitors and quinone outside inhibitors has been addressed before in net blotches, mechanisms controlling demethylation inhibitor resistance have not yet been reported at the molecular level. Here we report the isolation of strains of NFNB in Australia since 2013 resistant to a range of demethylase inhibitor fungicides. Cyp51A:KO103-A1, an allele with the mutation F489L, corresponding to the archetype F495I in Aspergillus fumigatus, was only present in resistant strains and was correlated with resistance factors to various demethylase inhibitors ranging from 1.1 for epoxiconazole to 31.7 for prochloraz. Structural in silico modeling of the sensitive and resistant CYP51A proteins docked with different demethylase inhibitor fungicides showed how the interaction of F489L within the heme cavity produced a localized constriction of the region adjacent to the docking site that is predicted to result in lower binding affinities. Resistant strains also displayed enhanced induced expression of the two Cyp51A paralogs and of Cyp51B genes. While Cyp51B was found to be constitutively expressed in the absence of fungicide, Cyp51A was only detected at extremely low levels. Under fungicide induction, expression of Cyp51B, Cyp51A2, and Cyp51A1 was shown to be 1.6-, 3,- and 5.3-fold higher, respectively in the resistant isolate compared to the wild type. These increased levels of expression were not supported by changes in the promoters of any of the three genes. The implications of these findings on demethylase inhibitor activity will require current net blotch management strategies to be reconsidered in order to avoid the development of further resistance and preserve the lifespan of fungicides in use. [ABSTRACT FROM AUTHOR]

Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino acid substitutions is to cite the wild-type amino acid, the codon number and the new amino acid, using the one-letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the present paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well-studied 'archetype' species. Orthologous amino acids in all species are then assigned numerical 'labels' based on the position of the amino acid in the archetype protein. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aspergillus spp. are important fungi because of the high mortality associated with aspergillosis. However, we have only three classes of anti-aspergillus drugs available; and only two drugs, itraconazole (ITCZ) and voriconazole (VRCZ), are available as oral agents in Japan. If azole-resistant Aspergillus causes chronic aspergillosis, we cannot treat such patients with oral azoles on an outpatient basis. As is the case with foreign countries, we found the existence of azole-resistant Aspergillus fumigatus in clinical settings in Japan. Resistance was attributed to mutations of the target protein (CYP51A). Additionally, we also found that long-term itraconazole treatment induced G54 substitution in CYP51A, causing itraconazole-resistance. Although there are few resistant Aspergillus strains existing in Japan now, we have to continue to find such resistant isolates, which are spreading worldwide. [ABSTRACT FROM AUTHOR]

Although a worldwide health problem, leishmaniasis is considered a highly neglected disease, lacking efficient and low toxic treatment. The efforts for new drug development are based on alternatives such as new uses for well-known drugs, in silico and synthetic studies and naturally derived compounds. Oleanolic acid (OA) is a pentacyclic triterpenoid widely distributed throughout the Plantae kingdom that displays several pharmacological activities. OA showed potent leishmancidal effects in different Leishmania species, both against promastigotes (IC 50 L. braziliensis 30.47 ± 6.35 μM; IC 50 L. amazonensis 40.46 ± 14.21 μM; IC 50 L. infantum 65.93 ± 15.12 μM) and amastigotes (IC 50 L. braziliensis 68.75 ± 16.55 μM; IC 50 L. amazonensis 38.45 ± 12.05 μM; IC 50 L. infantum 64.08 ± 23.52 μM), with low cytotoxicity against mouse peritoneal macrophages (CC 50 235.80 ± 36.95 μM). Moreover, in silico studies performed to evaluate OA molecular properties and to elucidate the possible mechanism of action over the Leishmania enzyme sterol 14α-demethylase (CYP51) suggested that OA interacts efficiently with CYP51 and could inhibit the ergosterol synthesis pathway. Collectively, these data indicate that OA is a good candidate as leading compound for the development of a new leishmaniasis treatment. [ABSTRACT FROM AUTHOR]

Sterol 14α-demethylase (CYP51) is a key enzyme involved in the survival and virulence of many parasite protozoa, such as Trypanosoma and Leishmania species, thus representing a valuable drug target for the treatment of Kinetoplastid diseases. A set of azole-based compounds selected from an in-house compound library was in vitro screened against different human protozoan parasites. Several compounds showed selective activity against Trypanosoma cruzi , with compound 7 being the most active (IC 50 = 40 nM). Given the structural similarity between the compounds here reported and known CYP51 inhibitors, a molecular docking study was performed to assess their binding with protozoal target and to rationalize the biological activity data. [ABSTRACT FROM AUTHOR]

Diabetic dyslipidemia requires simultaneous treatment with hypoglycemic agents and lipid-modulating drugs. We recently described glycogen phosphorylase inhibitors that reduce glycogenolysis in cells and lower plasma glucose in ob/ob mice (J. Med. Chem., 41: 2934, 1998). In evaluating the series prototype, CP-320626, in dogs, up to 90% reduction in plasma cholesterol was noted after 2 week treatment. Cholesterol reductions were also noted in ob/ob mice and in rats. In HepG2 cells, CP-320626 acutely and dose-dependently inhibited cholesterolgenesis without affecting fatty acid synthesis. Inhibition occurred together with a dose-dependent increase in the cholesterol precursor, lanosterol, suggesting that cholesterolgenesis inhibition was due to lanosterol 14α-demethylase (CYP51) inhibition. In ob/ob mice, acute treatment with CP-320626 resulted in a decrease in hepatic cholesterolgenesis with concomitant lanosterol accumulation, further implicating CYP51 inhibition as the mechanism of cholesterol lowering in these animals. CP-320626 and analogs directly inhibited rhCYP51, and this inhibition was highly correlated with HepG2 cell cholesterolgenesis inhibition (R2 = 0.77).These observations indicate that CP-320626 inhibits cholesterolgenesis via direct inhibition of CYP51, and that this is the mechanism whereby CP-320626 lowers plasma cholesterol in experimental animals. Dual-action glycogenolysis and cholesterolgenesis inhibitors therefore have the potential to favorably affect both the hyperglycemia and the dyslipidemia of type 2 diabetes.

Prochloraz has been used to control Fusarium fujikuroi , the causative pathogen of rice bakanae disease. Linkage analysis of FfCYP51 genes in the progenies obtained from crossing prochloraz moderately resistant and sensitive strains suggested that the FfCYP51B gene is involved in prochloraz resistance. Sequence comparison revealed that the prochloraz-resistant strain had an F511S or S312T/F511S substitution in FfCYP51B compared with the sensitive strains. The contribution of the S312T and F511S substitutions in FfCYP51B to prochloraz resistance was investigated by creating S/F-, T/F-, or T/S- types at 312/511 codons from the S/S-type, which is a natural moderately resistant strain, using a gene-editing technique. T/S exhibited the highest prochloraz resistance, followed by S/S-, T/F-, and S/F-types. These results indicated that the S312T and F511S substitutions in FfCYP51B had a synergistic effect on prochloraz resistance in F. fujikuroi. [Display omitted] • The F511S or S312T/ F511S substitution in FfCYP51B was detected in prochloraz resistant Fusarium fujikuroi in Japan. • Synergistic effect of the S312T and F511S substitution in FfCYP51B for prochloraz resistance was confirmed by a gene-editing technique. • Molecular docking analysis suggested that double substitution S312T/ F511S resulted in weaker binding between prochloraz and FfCYP51B than a single substitution. [ABSTRACT FROM AUTHOR]

Cholesterol is the precursor of bioactive plant metabolites such as steroidal saponins. An Australian plant, Dioscorea transversa, produces only two steroidal saponins: 1β-hydroxyprotoneogracillin and protoneogracillin. Here, we used D. transversa as a model in which to elucidate the biosynthetic pathway to cholesterol, a precursor to these compounds. Preliminary transcriptomes of D. transversa rhizome and leaves were constructed, annotated, and analyzed. We identified a novel sterol side-chain reductase as a key initiator of cholesterol biosynthesis in this plant. By complementation in yeast, we determine that this sterol side-chain reductase reduces Δ 24,28 double bonds required for phytosterol biogenesis as well as Δ 24,25 double bonds. The latter function is believed to initiate cholesterogenesis by reducing cycloartenol to cycloartanol. Through heterologous expression, purification, and enzymatic reconstitution, we also demonstrate that the D. transversa sterol demethylase (CYP51) effectively demethylates obtusifoliol, an intermediate of phytosterol biosynthesis and 4-desmethyl-24,25-dihydrolanosterol, a postulated downstream intermediate of cholesterol biosynthesis. In summary, we investigated specific steps of the cholesterol biosynthetic pathway, providing further insight into the downstream production of bioactive steroidal saponin metabolites., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Candida albicans , an opportunistic pathogen, is the most common type of fungus and represents a substantial source of human invasive disease (nosocomial infection). This category of fungi are part of our microbiota, and given the appropriate environmental conditions, it has the potential to cause both superficial and systemic infections. There is a soaring resistance against the available anticandidal agents. The purpose of this research is to investigate the activity of certain previously synthesized benzo[ g ]quinazolines against C. albicans in vitro by using the cup-plate diffusion method. There was a marked difference in the effectiveness of the target compounds 1-6 against the sample of C. albicans that was tested. Benzo[ g ]quinazolines 1 (inhibition zone = 20 mm) and 2 (inhibition zone = 22 mm) had good effects in comparison to fluconazole (inhibition zone = 26 mm). A docking study was conducted between benzo[ g ]quinazolines 1-6 and Candida spp. CYP51 to establish the binding mode compared with fluconazole and VT-1161 (oteseconazole) as reference medicines, and it was determined that binding at the active site of Candida spp. CYP51 occurred in the same manner. Quantitative structure-activity relationship (QSAR) investigation was performed to further characterize the identified anticandidal agents and recognize the major regulatory components governing such activity. In future studies, the benzo[ g ]quinazoline scaffold could serve as a model for the design and development of novel derivatives with antifungal potential., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Nine new functionally substituted derivatives of 2-aminothiazole were evaluated for antimicrobial activity using microdilution method against the panel of eight bacterial and eight fungal strains. Evaluation of antibacterial activity revealed that compounds are potent antibacterial agents, more active than ampicillin and streptomycin except of some compounds against B. cereus and En. cloacae . The best compound appeared to be compound 8. The most sensitive bacteria appeared to be En. cloacae , while L. monocytogenes was the most resistant. Compounds also exhibited good antifungal activity much better than two reference drugs, ketoconazole and bifonazole. Compound 1 exhibited the best antifungal activity. The most sensitive fungus was T. viride , while A. fumigatus was the most resistant. Bacteria as well as fungi in general showed different sensitivity towards compounds tested. Molecular docking studies revealed that MurB inhibition is probably involved in the mechanism of antibacterial activity, while CYP51 of C. albicans is responsible for the mechanism of antifungal activity. Finally, it should be mentioned that all compounds displayed very good druglikeness scores.