Azole derivatives inhibit wildtype butyrylcholinesterase and its common mutants.

Azoles, which have been used for antifungal chemotherapy for decades, have recently been of interest for their efficacy against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). There is little known about the potential of azoles against BChE, however there is none regarding their inhibitory effects against mutants of BChE. In the current study, an azole library of 1-aryl-2-(1H-imidazol-1-yl)ethanol/ethanone oxime esters were tested against AChE and BChE, which yielded derivates more potent than the positive control, galantamine, against both isoforms. Kinetic analyses were performed for wildtype and mutant (A328F and A328Y) inhibition for the two most potent BChE inhibitors, pivalic and 3-bezoylpropanoic acid esters of 2-(1H-imidazol-1-yl)-1-(2-naphthyl)ethanol, which were found to have great affinity to the wildtype and mutant BChE types with Ki values as low as 0.173 ± 0.012 µM. The compounds were identified to show linear competitive or mixed type inhibition. Molecular modeling confirmed these kinetic data and provided further insights regarding molecular basis of BChE inhibition by the active derivatives. Thus, current study suggests new azole derivatives with promising cholinesterase inhibitory effects and reveals the first set of information to promote our understanding for the inhibitory behavior of this class against the mutant BChE forms.

Antifungal Azole Derivatives Featuring Naphthalene Prove Potent and Competitive Cholinesterase Inhibitors with Potential CNS Penetration According to the in Vitro and in Silico Studies.

Cholinesterase inhibition is of great importance in the fight against neurodegenerative disorders such as Alzheimer's disease. Azole antifungals have come under the spotlight with recent discoveries that underline the efficacy and potential of miconazole and its derivatives against cholinesterase enzymes. In this study, we evaluated a library of azoles against acetylcholinesterase and butyrylcholinesterase using in vitro and in silico methods to identify potent inhibitors. Low micromolar IC50 values were obtained for imidazole derivatives, which were further tested and found potent competitive cholinesterase inhibitors via enzyme kinetics study. The active derivatives showed negligible toxicity in in vitro cytotoxicity tests. Molecular modeling studies predicted that these derivatives were druglike, could penetrate blood-brain barrier, and tightly bind to cholinesterase active site making key interactions via the imidazole moiety at protonated state. Thus, current study identifies potent and competitive cholinesterase inhibitor azoles with minor toxicity and potential to pass into the central nervous system.

Azoles containing naphthalene with activity against Gram-positive bacteria: in vitro studies and in silico predictions for flavohemoglobin inhibition.

Azoles are first-line drugs used in fungal infections. Topical antifungals, such as miconazole and econazole, are known to be active against Gram-positive bacteria, which was reported to result from bacterial flavohemoglobin (flavoHb) inhibition. Dual antibacterial/antifungal action is believed to have benefits for antimicrobial chemotherapy. In this study, we tested antibacterial effects of an in-house library of naphthalene-bearing azoles, some of which were reported as potent antifungals, in an attempt to find dual-acting hits. Several potent derivatives were obtained against the Gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus. 9 was active at a minimum inhibitor concentration (MIC) less than 1 µg/ml against E. faecalis and S. aureus, and 10 against S. aureus. 16 was also potent against E. faecalis and S. aureus (MIC = 1 and 2 µg/ml, respectively). Six more were active against S. aureus with MIC ≤ 4 µg/ml. In vitro cytotoxicity studies showed that the active compounds were safe for healthy cells within their MIC ranges. According to the calculated descriptors, the library was found within the drug-like chemical space and free of pan-assay interference compounds (PAINS). Molecular docking studies suggested that the compounds might be bacterial flavohemoglobin (flavoHb) inhibitors and the azole and naphthalene rings were important pharmacophores, which was further supported by pharmacophore modeling study. As a result, the current study presents several non-toxic azole derivatives with antibacterial effects. In addition to their previously reported antifungal properties, they could set a promising starting point for the future design of dual acting antimicrobials. Communicated by Ramaswamy H. Sarma.

Histological assessment of liver and stomach damage caused by pyridazinone derivative antidepressant agents.

Depression is a serious psychological disorder that affects a significant population. We investigated the antidepressant activities of four pyridazinone derivatives that contain the hydrazide moiety using the forced swimming test (FST). The compounds tested exhibited good antidepressant activity compared to duloxetine. The most promising compound was compound 2, which reduced the duration of immobility during FST. The toxic effects of the four compounds on the histomorphology of the liver and stomach tissue also was evaluated.

Azole derivatives with naphthalene showing potent antifungal effects against planktonic and biofilm forms of Candida spp.: an in vitro and in silico study.

Candida infections pose a serious public health threat due to increasing drug resistance. Azoles are first-line antifungal drugs for fungal infections. In this study, we tested an in-house azole collection incorporating naphthalene ring to find hits against planktonic and biofilm forms of resistant Candida spp. In the collection, potent derivatives were identified against the susceptible strains of Candida with minimum inhibitory concentration (MIC) values lower than those of the reference drug, fluconazole. MIC values of 0.125 µg/ml against C. albicans, 0.0625 µg/ml against C. parapsilosis, and 2 µg/ml against C. krusei, an intrinsically azole-resistant non-albicans Candida, were obtained. Some of the derivatives were highly active against fluconazole-resistant clinical isolate of C. tropicalis. Inhibition of C. albicans biofilms was also observed at 4 µg/ml similar as amphotericin B, the reference drug known for its antibiofilm activity. Through molecular docking studies, affinities and key interactions of the compounds with fungal lanosterol 14α-demethylase (CYP51), the target enzyme of azoles, were predicted. The interactions of imidazole with heme cofactor and of the naphthalene with Tyr118 were highlighted in line with the literature data. As a result, this study proves the importance of naphthalene for the antifungal activity of azoles against Candida spp. in both planktonic and biofilm forms.

Antibacterial azole derivatives: Antibacterial activity, cytotoxicity, and in silico mechanistic studies.

Azole antifungal drugs are commonly used in antifungal chemotherapy. Antibacterial effects of some topical antifungals, such as miconazole and econazole, have lately been revealed, which suggests a promising venue in antimicrobial chemotherapy. In this study, we tested an in-house azole collection with antifungal properties for their antibacterial activity to identify dual-acting hits using the broth microdilution method. The in vitro screen yielded a number of potent derivatives against gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus. Compound 73's minimum inhibitory concentration (MIC) value less than 1 µg/ml against S. aureus; however, none of the compounds showed noteworthy activity against methicillin-resistant S. aureus (MRSA). All the active compounds were found safe at their MIC values against the healthy fibroblast cells in the in vitro cytotoxicity test. Molecular docking studies of the most active compounds using a set of docking programs with flavohemoglobin (flavoHb) structure, the proposed target of the azole antifungals with antibacterial activity, presented striking similarities regarding the binding modes and interactions between the tested compounds and the antifungal drugs with crystallographic data. In addition to being noncytotoxic, the library was predicted to be drug-like and free of pan-assay interference compounds (PAINS). As a result, the current study revealed several potential azole derivatives with both antifungal and antibacterial activities. Inhibition of bacterial flavoHb was suggested as a possible mechanism of action for the title compounds.

Synthesis, molecular modelling and biological activity of some pyridazinone derivatives as selective human monoamine oxidase-B inhibitors.

BACKGROUND: Since brain neurotransmitter levels are associated with the pathology of various neurodegenerative diseases like Parkinson and Alzheimer, monoamineoxidase (MAO) plays a critical role in balancing these neurotransmitters in the brain. MAO isoforms appear as promising drug targets for the development of central nervous system agents. Pyridazinones have a broad array of biological activities. Here, six pyridazinone derivatives were synthesized and their human monoamine oxidase inhibitory activities were evaluated by molecular docking studies, in silico ADME prediction and in vitro biological screening tests. METHODS: The compounds were synthesized by the reaction of different piperazine derivatives with 3 (2H)-pyridazinone ring and MAO-inhibitory effects were investigated. Docking studies were conducted with Maestro11.8 software. RESULTS: Most of the synthesized compounds inhibited hMAO-B selectively except compound 4f. Compounds 4a-4e inhibited hMAO-B selectively and reversibly in a competitive mode. Compound 4b was found as the most potent (ki = 0.022 ± 0.001 µM) and selective (SI (Ki hMAO-A/hMAO-B) = 206.82) hMAO-B inhibitor in this series. The results of docking studies were found to be consistent with the results of the in vivo activity studies. Compounds 4a-4e were found to be non-toxic to HepG2 cells at 25 µM concentration. In silico calculations of ADME properties indicated that the compounds have good pharmacokinetic profiles. CONCLUSION: It was concluded that 4b is possibly recommended as a promising nominee for the design and development of new pyridazinones which can be used in the treatment of neurological diseases.

Antifungal screening and in silico mechanistic studies of an in-house azole library.

Systemic Candida infections pose a serious public health problem with high morbidity and mortality. C. albicans is the major pathogen identified in candidiasis; however, non-albicans Candida spp. with antifungal resistance are now more prevalent. Azoles are first-choice antifungal drugs for candidiasis; however, they are ineffective for certain infections caused by the resistant strains. Azoles block ergosterol synthesis by inhibiting fungal CYP51, which leads to disruption of fungal membrane permeability. In this study, we screened for antifungal activity of an in-house azole library of 65 compounds to identify hit matter followed by a molecular modeling study for their CYP51 inhibition mechanism. Antifungal susceptibility tests against standard Candida spp. including C. albicans revealed derivatives 12 and 13 as highly active. Furthermore, they showed potent antibiofilm activity as well as neglectable cytotoxicity in a mouse fibroblast assay. According to molecular docking studies, 12 and 13 have the necessary binding characteristics for effective inhibition of CYP51. Finally, molecular dynamics simulations of the C. albicans CYP51 (CACYP51) homology model's catalytic site complexed with 13 were stable demonstrating excellent binding.

Discovery of new azoles with potent activity against Candida spp. and Candida albicans biofilms through virtual screening.

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.

Synthesis, anticonvulsant screening, and molecular modeling studies of new arylalkylimidazole oxime ether derivatives.

In this study, 15 new oxime ether derivatives were synthesized and their anticonvulsant activities were screened in vivo. The compounds were synthesized by the reaction of various alkyl halides with 1-(2-naphthyl)-2-(1H-imidazol-1-yl)ethanone oxime. Their anticonvulsant activities were determined using acute (maximal electroshock, subcutaneous metrazol [SCM], and 6 Hz seizure test) and chronic (corneal-kindled mouse) seizure models, their neurotoxic effects were evaluated by models of behavioral toxicity according to the Epilepsy Therapy Screening Program protocol of the NIH. All our compounds were protective in at least one of the tests. Quantification studies were applied to some of the active compounds and the intraperitoneal ED50 values in mice were found between 25.48 and 99.56 mg/kg. Some pharmacokinetic properties of the compounds were predicted in silico and molecular docking studies were performed to provide insights into their possible anticonvulsant mechanism regarding their SCM activity.

New Anti-Seizure (Arylalkyl)azole Derivatives: Synthesis, In Vivo and In Silico Studies.

(Arylalkyl)azoles are a class of antiepileptic compounds including nafimidone, denzimol, and loreclezole (LRZ). Nafimidone and denzimol are thought to inhibit voltage-gated sodium channels (VGSCs) and enhance γ-aminobutyric acid (GABA)-mediated response. LRZ, a positive allosteric modulator of A-type GABA receptors (GABAA Rs), was reported to be sensitive to Asn265 of the ß2/ß3 subunit. Here, we report new N-[1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene]hydroxylamine esters showing anticonvulsant activity in animal models, including the 6-Hz psychomotor seizure test, a model for therapy-resistant partial seizure. We performed molecular docking studies for our active compounds using GABAA R and VGSC homology models. They predicted high affinity to the benzodiazepine binding site of GABAA R in line with the experimental results. Also, the binding mode and interactions of LRZ in its putative allosteric binding site of GABAA R is elucidated.

New (arylalkyl)azole derivatives showing anticonvulsant effects could have VGSC and/or GABAAR affinity according to molecular modeling studies.

(Arylalkyl)azoles (AAAs) emerged as a novel class of antiepileptic agents with the invention of nafimidone and denzimol. Several AAA derivatives with potent anticonvulsant activities have been reported so far, however neurotoxicity was usually an issue. We prepared a set of ester derivatives of 1-(2-naphthyl)-2-(1H-1,2,4-triazol-1-yl)ethanone oxime and evaluated their anticonvulsant and neurotoxic effects in mice. Most of our compounds were protective against maximal electroshock (MES)- and/or subcutaneous metrazol (s.c. MET)-induced seizures whereas none of them showed neurotoxicity. Nafimidone and denzimol have an activity profile similar to that of phenytoin or carbamazepine, both of which are known to inhibit voltage-gated sodium channels (VGSCs) as well as to enhance γ-aminobutiric acid (GABA)-mediated response. In order to get insights into the effects of our compounds on VGSCs and A-type GABA receptors (GABAARs) we performed docking studies using homology model of Na+ channel inner pore and GABAAR as docking scaffolds. We found that our compounds bind VGSCs in similar ways as phenytoin, carbamazepine, and lamotrigine. They showed strong affinity to benzodiazepine (BZD) binding site and their binding interactions were mainly complied with the experimental data and the reported BZD binding model.

Coumarin or benzoxazinone based novel carbonic anhydrase inhibitors: synthesis, molecular docking and anticonvulsant studies.

Among many others, coumarin derivatives are known to show human carbonic anhydrase (hCA) inhibitory activity. Since hCA inhibition is one of the underlying mechanisms that account for the activities of some antiepileptic drugs (AEDs), hCA inhibitors are expected to have anti-seizure properties. There are also several studies reporting compounds with an imidazole and/or benzimidazole moiety which exert these pharmacological properties. In this study, we prepared fifteen novel coumarin-bearing imidazolium and benzimidazolium chloride, nine novel benzoxazinone-bearing imidazolium and benzimidazolium chloride derivatives and evaluated their hCA inhibitory activities and along with fourteen previously synthesized derivatives we scanned their anticonvulsant effects. As all compounds inhibited purified hCA isoforms I and II, some of them also proved protective against Maximal electroshock seizure (MES) and ScMet induced seizures in mice. Molecular docking studies with selected coumarin derivatives have revealed that these compounds bind to the active pocket of the enzyme in a similar fashion to that previously described for coumarin derivatives.

Synthesis, anticonvulsant and antimicrobial activities of some new [1-(2-naphthyl)-2-(pyrazol-1-yl)ethanone]oxime ethers.

In this study, 12 new oxime ether derivatives, which were expected to show anticonvulsant and antimicrobial activities, were synthesized. Oxime ether derivatives were synthesized by the reaction of various alkyl halides with 1-(2- naphthyl)-2-(pyrazol-1-yl)ethanone oxime. Anticonvulsant activity of the compounds was determined by maximal electroshock (MES) and subcutaneous metrazol (ScM) seizure tests, while neurological disorders were evaluated using rotorod toxicity test according to the ASP of NIH. Compound 1, 6 and 7 showed anticonvulsant activity at 300 mg/kg dose at 4 h, but compounds 1 and 7 showed toxicity at 300 mg/kg dose at half an hour. Antimicrobial activities of the compounds were also determined using agar microdilution method. Compound 1 and 5 were found to have the highest antifungal activity among the other compounds.

Evaluation of the effects of novel nafimidone derivatives on thermal hypoalgesia in mice with diabetic neuropathy.

OBJECTIVE: Diabetic neuropathy (DN) is a common complication in Diabetes Mellitus. The streptozotocin-induced diabetic rodent is the most commonly used animal model of diabetes and increased sodium channel expression and activity were revealed in this model. At this study, we evaluated the effect of three different nafimidone derivatives which have possible anticonvulsant activity on disorders of thermal pain sensation in diabetic mice. STUDY DESIGN: Randomized animal experiment. MATERIAL AND METHODS: Mice were divided randomly into five groups (5 mice per group): Control, Diabetes, Dibetes+C1, Diabetes+C2, Diabetes+C3. We used hot and cold plate, and tail-immersion tests for assessment of thermal nociceptive responses. RESULTS: Compared with the control group, the hot-plate response time and the number of paw liftings on cold plate as important indicators of loss of sensation increased, but no significant difference (p>0.05) was found in tail-immersion response time test in diabetes group. C3 compound moved it back to control group levels in the all of three tests. C1 and C2 compounds were effective only in cold-plate test. CONCLUSION: Nafimidone derivatives may be effective in the cases where epilepsy and diabetes occur together since it has shown efficacy against "loss of sensation" which evolves in diabetic neuropathy over time as well as its antiepileptic effect.

Synthesis of some novel 1-(2-naphthyl)-2-(imidazol-1-yl)ethanone oxime ester derivatives and evaluation of their anticonvulsant activity.

Twenty-three new oxime ester derivatives of nafimidone were synthesized with the prospect of potential anticonvulsant activities. MES and ScM tests were employed for their anticonvulsant activities and rotorod test for neurological deficits. Eighteen compounds were found to be protective against MES seizures. Alkyl (1-8) and arylalkyl (9, 10) oxime ester derivatives were found to be more active than aryl oxime ester derivatives (11-23). Five compounds (2, 3, 7, 9, 10), which were protective at 0.5 h at the doses of 30 mg/kg and higher in MES test, showed the highest activity. Compound 17 was the most active one in ScM test at all dose levels at 4 h.

Recent progress in anticonvulsant drug research: strategies for anticonvulsant drug development and applications of antiepileptic drugs for non-epileptic central nervous system disorders.

Major advances in antiepileptic drug therapy have taken place since 1950s. In the first period, several antiepileptic drugs (AEDs) such as phenobarbital, diphenylhydantoin, ethosuximide, carbamazepine, benzodiazepines and valproic acid were introduced to epilepsy treatment. After 1990 many new generation drugs (lamotrigine, topiramate, gabapentine, pregabaline, felbamate, lacosamide, levetiracetam etc.) have been developed. These novel AEDs have offered some advantages such as fewer side effects, fewer drug-drug interactions, and better pharmacokinetic properties. But pharmacoresistance and therapeutic failure in 20-25% of the patients remain the main reasons to continue efforts to find safer and more efficacious drugs and ultimate a treatment for this devastating disease. Several AEDs especially novel compounds have been found to be effective also in the treatment of several other neurologic and psychiatric disorders. Chemical diversity of the newer antiepileptic drugs as well as those currently in clinical development is another point that encourages medicinal chemists to study this subject. This review summarizes recent studies on the development of potential anticonvulsant compounds in different chemical structures, their structure-activity relationships and also therapeutic usages of AEDs other than epilepsy.

Synthesis, anticonvulsant and antimicrobial activities of some new 2-acetylnaphthalene derivatives.

In this study, as a continuation of our research for new (arylalkyl)imidazole anticonvulsant compounds, the design, synthesis and anticonvulsant/antimicrobial activity evaluation of a series of 2-acetylnaphthalene derivatives have been described. Molecular design of the compounds has been based on the modification of nafimidone [1-(2-naphthyl)-2-(imidazol-1-yl)ethanone], which is a representative of the (arylalkyl)imidazole anticonvulsant compounds as well as its active metabolite, nafimidone alcohol (3, 4). In general, these compounds were variously substituted at the alkyl chain between naphthalene and imidazole rings and subjected to some other modifications to evaluate additional structure-activity relationships. The anticonvulsant activity profile of those compounds was determined by maximal electroshock seizure (MES) and subcutaneous metrazol (scM) seizure tests, whereas their neurotoxicity was examined using rotarod test. All the ester derivatives of nafimidone alcohol (5a-h), which were designed as prodrugs, showed anticonvulsant activity against MES-induced seizure model. Four of the most active compounds were chosen for further anticonvulsant evaluations. Quantification of anticonvulsant protection was calculated via the ip route (ED(50) and TD(50)) for the most active candidate (5d). Observed protection in the MES model was 38.46mgkg(-1) and 123.83mgkg(-1) in mice and 20.44mgkg(-1), 56.36mgkg(-1) in rats, respectively. Most of the compounds with imidazole ring also showed antibacterial and/or antifungal activities to a certain extent in addition to their anticonvulsant activity.

Synthesis of some oxime ether derivatives of 1-(2-naphthyl)-2-(1,2,4-triazol-1-yl)ethanone and their anticonvulsant and antimicrobial activities.

In this study, oxime and oxime ether derivatives of [1-(2-naphthyl)-2-(1,2,4-triazol-1-yl)ethanone] were prepared as potential anticonvulsant and antimicrobial compounds. The oxime was synthesized by the reaction of ketone and hydroxylamine hydrochloride. O-Alkylation of the oxime by various alkyl halides gave the oxime ether derivatives. Anticonvulsant activity of the compounds was determined by maximal electroshock and subcutaneous metrazole tests in mice and rats according to procedures of the Anticonvulsant Screening Program of National Institutes of Health. Neurotoxicity was determined by the rotorod test in mice and the positional sense test, gait and stance test in rats. In addition to anticonvulsant tests, all compounds were also evaluated against the following microorganisms: S. aureus, E. coli, P. aeruginosa, E. faecalis, C. albicans, C. parapsilosis, and C. krusei using microdilution broth method for possible antibacterial and antifungal activities. Although most of the O-alkyl substituted oxime ethers exhibited both anticonvulsant and antimicrobial activities, the O-arylalkyl substituted compounds were found to be inactive in both screening paradigms.