Synthesis, in vitro potency of inhibition, enzyme kinetics and in silico studies of quinoline-based α-glucosidase inhibitors.

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target α-glucosidase, which catalyzes starch hydrolysis in the intestine. In an attempt to find potential α-glucosidase inhibitors, a series of twenty new quinoline linked benzothiazole hybrids (8a-t) were synthesized in good yields from suitable reaction procedures and their chemical structures were analyzed by 1HNMR, 13CNMR, IR, and ESI-MS analysis. The synthesized derivatives further screened for their activity against α-glucosidase. Among them, compounds 8b, 8h, 8n and 8o exhibited remarkable α-glucosidase inhibitory activity with IC50 values ranging from 38.2 ± 0.3 to 79.9 ± 1.2 µM compared with standard drug acarbose (IC50 = 750.0 ± 2.0 µM). Enzyme kinetic studies of the most active compound (8h) indicated a non-competitive inhibition with Ki value of 38.2 µM. Moreover, the homology modeling, molecular docking and molecular dynamics simulation studies were conducted to reveal key interactions between the most active compound 8h and the targeted enzyme. These results are complementary to the experimental observations. In order to predict the druggability of the novel derivatives, the pharmacokinetic properties were also applied. These findings could be useful for the design and development of new α-glucosidase inhibitors.

Synthesis, Sensing Performance and DFT Studies of a Novel Coumarin-based Schiff Base As a Turn-on Fluorescence Probe for Zinc Ion Detection.

The design and development of novel efficient fluorescent chemical sensors for the selective detection of ions is currently of significant importance in supramolecular chemistry. Since zinc is a ubiquitous, indispensable and the second most abundant metal ion in the human body, developing chemosensors that can accurately discriminate between Zn2+ and Cd2+ ions has been a challenge due to their similar properties as they are in the same group of the periodic table. Therefore, a technique to trace and visualize free zinc ions is demanded. In this study, an innovative coumarin-based Schiff base (L) was synthesized and characterized by 1H NMR, 13C NMR and mass spectroscopy. A novel "Turn On" fluorescence chemosensor platform was developed for trace amounts of Zn2+ ions. The fluorescence Job's plot measurement was used to determine the complexation ratio between the probe and Zn2+ ion, which showed a maximum point indicating the formation of a ML2 adduct. Additionally, the geometrical parameters calculated using DFT and TD-DFT calculations were in close agreement with the experimentally observed values.

In-vivo efficiency of the novel azole compounds (ATTAF-1 and ATTAF-2) against systemic candidiasis in a murine model.

BACKGROUND: Antifungal resistance is the main health concern in the control of invasive fungal infections. This research was designed to further assess the antifungal activity of aryl-1,2,4-triazole-3-ylthio analogs of fluconazole (ATTAFs) against Candida albicans systemic candidiasis in the murine model. MATERIALS & METHODS: The murine model of systemic candidiasis was designed via the inoculation of 1 × 106 CFU of Candida albicans. The treatment dosages of 3.5 and 35 mg/kg per day were selected for ATTAFs and fluconazole, respectively. The median survival time (MST) was assayed for 30 days post-infection. The quantitative and qualitative (via histopathology staining) fungal burden was also assessed. Furthermore, immunohistochemistry and biochemistry assays were performed to monitor anti-inflammatory activity using the Cyclooxygenase-2 (Cox-2) marker and changes in serum protein levels. RESULTS: ATTAFs considerably improved the survival of the murine model (P < 0.003). Compared with fluconazole, the antifungal activity of ATTAFs and their MST showed no difference (P > 0.05). However, these compounds decreased the fungal burden in the kidneys, spleen, and liver. CONCLUSION: Our research indicates that ATTAF-1 and ATTAF-2 are effective therapeutic agents due to their fungal clearing and increasing the MST in the murine model of systemic candidiasis. Although we concluded that these components are novel and promising candidates for the management of invasive candidiasis, further studies are warranted to correlate these findings with clinical outcomes.

Design, synthesis and biological activity of hybrid antifungals derived from fluconazole and mebendazole.

A novel series of triazole alcohol antifungals bearing a 5-benzoylbenzimidazol-2-ylthio side chain have been designed and synthesized as hybrids of fluconazole (a typical triazole antifungal) and mebendazole (an anthelmintic agent with antifungal activity). The title compounds were synthesized via the reaction of an appropriate oxirane and desired 2-mercaptobenzimidazole. Although there was possibility for formation of different N-substituted or S-substituted products, the structures of final compounds were assigned as thioether congeners by using 13C NMR spectroscopy. The SAR analysis of the primary lead compounds (series A) was conducted by simplifying the 5-benzoylbenzimidazol-2-ylthio residue to the benzimidazol-2-ylthio (series B) or benzothiazol-2-ylthio side chain (series C), and modification of halogen substituent on the phenethyl-triazole scaffold. In general, series A (compounds 4a-e) containing 5-benzoylbenzimidazole scaffold showed better antifungal activity against Candida spp. and Cryptococcus neoformans than related benzimidazole and benzothiazole derivatives. The better results were obtained with the 4-chloro derivative 4b displaying MICs <0.063-1 µg/mL. Although, removing benzoyl group from compound 4b had negative effect on the activity, optimization of phenethyl-triazole scaffold by desired halogen substituent resulted in compound 5c being as potent as 4b. In vitro and in silico ADMET evaluations of the most promising compounds 4b and 5c indicated that the selected compounds have desirable ADMET properties in comparison to standard drug fluconazole. Docking simulation study demonstrated that the benzimidazol-2-ylthio moiety is responsible for the potent antifungal activity of these compounds.

Synthesis of 4-Hydroxycoumarin-Based Triazoles/Oxadiazoles as Novel Anticancer Agents.

A series of novel 3-substituted-4-hydroxycoumarins 7 and 8 containing (5-aryl-1,3,4-oxadiazol-2-yl)thio or (4-amino-5-aryl-4H-1,2,4-triazol-3-yl)thio moieties have been synthesized and evaluated as anticancer agents. The in vitro MTT assay of compounds against hepatocellular carcinoma (HepG2), breast cancer (MCF7) cells, and a human colorectal adenocarcinoma cell line with epithelial morphology (HT29) indicated that the HepG2 cells had more susceptibility to the tested compounds. Indeed, all compounds (with the exception of 7b, 7c, 7g, and 8g) were more potent than the standard drug doxorubicin against HepG2 cells (IC50 values=1.65-3.83 µM). Although, the better result was obtained with the oxadiazole analog 7h against HepG2 (IC50 =1.65 µM), the N-amino-triazole derivatives 8c, 8e, 8f and, 8h with IC50 values of 1.78-6.34 µM showed potent activity against all tested cell lines. The good drug-like properties and in vitro potency and selectivity of 4-hydroxycoumarins 8 make them as good leads for the development of new anticancer agents.

Development and therapeutic potential of 2-aminothiazole derivatives in anticancer drug discovery.

Currently, the development of anticancer drug resistance is significantly restricted the clinical efficacy of the most commonly prescribed anticancer drug. Malignant disease is widely prevalent and considered to be the major challenges of this century, which concerns the medical community all over the world. Consequently, investigating small molecule antitumor agents, which could decrease drug resistance and reduce unpleasant side effect is more desirable. 2-aminothiazole scaffold has emerged as a promising scaffold in medicinal chemistry and drug discovery research. This nucleus is a fundamental part of some clinically applied anticancer drugs such as dasatinib and alpelisib. Literature survey documented that different 2-aminothiazole analogs exhibited their potent and selective nanomolar inhibitory activity against a wide range of human cancerous cell lines such as breast, leukemia, lung, colon, CNS, melanoma, ovarian, renal, and prostate. In this paper, we have reviewed the progresses and structural modification of 2-aminothiazole to pursuit potent anticancers and also highlighted in vitro activities and in silico studies. The information will useful for future innovation. Representatives of 2-aminothiazole-containing compounds classification.

Data on molecular docking of tautomers and enantiomers of ATTAF-1 and ATTAF-2 selectivty to the human/fungal lanosterol-14α-demethylase.

The data have been obtained for tautomers and enantiomers of ATTAF-1 and ATTAF-2 that were developed based on antifungal standard drugs with triazole scaffold. These compounds were docked into the human and fungal lanosterol-14α-demethylase. In order to validate the data, 8 standard triazole antifungal drugs (Fluconazole, Itraconazole, Posaconazole, Ravuconazole, Albaconazole, Voriconazole, Isavuconazole and Efinaconazole) were also docked into the human and fungal lanosterol-14α-demethylase. The binding conformations of these molecules and their interactions with lanosterol-14α-demethylase may inform the development of further small molecule lanosterol-14α-demethylase inhibitors with significant selectivity toward this enzyme. The analysis has done on the basis of type of interactions (bond type and distance). The length of the Fe-N coordination bond for (R)-N2-ATTAF-1 and (S)-N1-ATTAF-2 complexes is obtained 6.36 and 4.19 Å, respectively and about 2 Šin the other tautomer and enantiomer complexes, reflecting the lower basicity of the N-4 atom in the 1,2,4-triazole ring of (R)-N2-ATTAF-1 and (S)-N1-ATTAF-2 in comparison with the N-4 atom in the 1,2,4-triazole ring in other tautomers and enantiomers and supporting higher selectivity of (R)-N2-ATTAF-1 and (S)-N1-ATTAF-2 towards the target CYP51 enzymes vs. human. Interestingly, we have investigated unfavorable interactions (donor-donor) with TRP239 and MET378 for (R)-N2-ATTAF-1 and (S)-N1-ATTAF-2, respectively. These unfavorable interactions also have been seen in case of posaconazole and isavuconazole. The data presented in this article are related to the research paper entitled "In silico prediction of ATTAF-1 and ATTAF-2 selectivity towards human/fungal lanosterol 14α-demethylase using molecular dynamic simulation and docking approaches".

Design, synthesis and biological evaluation of flexible and rigid analogs of 4H-1,2,4-triazoles bearing 3,4,5-trimethoxyphenyl moiety as new antiproliferative agents.

Several flexible and rigid analogs of 4H-1,2,4-triazoles (compounds 8a-g and 9a-g) bearing trimethoxyphenyl pharmacophoric unit, were designed and synthesized as potential anticancer agents. The in vitro cytotoxic assay indicated that both flexible and rigid analogs (8 and 9, respectively) can potentially inhibit the growth of cancerous cells (A549, MCF7, and SKOV3), with IC50 values less than 5.0 µM. Furthermore, compounds 10a-l as regional isomers of compounds 9 exhibited remarkable cytotoxic activity with IC50 values ranging from 0.30 to 5.0 µM. The rigid analogs 9a, 10h and 10k were significantly more potent than etoposide against MCF7, SKOV3 and A549 cells, respectively. These compounds showed high selectivity towards cancer cells over normal cells, as they had no significant cytotoxicity against L929 cells. In addition, the representative compounds 9a and 10h could inhibit the tubulin polymerization at micro-molar levels. By determining changes in the colchicine-tubulin fluorescence, it was suggested that compound 10h could bind to the tubulin at the colchicine pocket. The molecular docking study further confirmed the inhibitory activity of promising compounds 9a, 10h and 10k on tubulin polymerization through binding to the colchicine-binding site.

New potent antifungal triazole alcohols containing N-benzylpiperazine carbodithioate moiety: Synthesis, in vitro evaluation and in silico study.

A number of 1H-1,2,4-triazole alcohols containing N-(halobenzyl)piperazine carbodithioate moiety have been designed and synthesized as potent antifungal agents. In vitro bioassays against different Candida species including C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis revealed that the N-(4-chlorobenzyl) derivative (6b) with MIC values of 0.063-0.5 µg/mL had the best profile of activity, being 4-32 times more potent than fluconazole. Docking simulation studies confirmed the better fitting of compound 6b in the active site of lanosterol 14α-demethylase (CYP51) enzyme, the main target of azole antifungals. Particularly, the potential of compound 6b against fluconazole-resistant isolates along with its minimal toxicity against human erythrocytes and HepG2 cells make this prototype compound as a good lead for discovery of potent and safe antifungal agents.

Current advances of triazole alcohols derived from fluconazole: Design, in vitro and in silico studies.

Currently, the available antifungal agents have significant clinical incompetency in terms of their clinical efficacy, antifungal spectrum, unfavorable pharmacokinetic profiles, substantial side effects and drug-drug interactions. Thus, the optimization and improvement of existing drugs and identification of new antifungal agents are urgently needed. Fluconazole is the first triazole alcohol drug with good in vivo efficacy against yeasts and well-known targets in fungal cells. However, the wide use of fluconazole as a first-line antifungal therapy has led to the development of resistance in clinical isolates of Candida species including Candida albicans and the emerging non-albicans Candida spp. In the last years, extensive efforts inflected to design and discovery of triazole alcohols derived from fluconazole by replacing one triazole ring with the proper side chain. In this paper, we have reviewed the structural modification of fluconazole to pursuit potent triazole alcohols with improved anti-Candida activity, and have highlighted their in vitro activities and in silico studies.

Acetophenone benzoylhydrazones as antioxidant agents: Synthesis, in vitro evaluation and structure-activity relationship studies.

Acetophenone and its analogues are naturally-occurring compounds found in many foods and plants. In this study, a series of acetophenone benzoylhydrazones 5a-o were designed and synthesized as new potential antioxidant agents. Designed molecules contain hydrazone and phenolic hydroxyl moieties which possibly contribute to antioxidant activity. The antioxidant properties of compounds 5a-o in terms of reducing ability and radical-scavenging activity were assessed by using FRAP and DPPH tests, respectively. While the unsubstituted compound 5a had the superior capacity in the FRAP assay, the 2,4-dihydroxyacetophenone analogue 5g was the most potent radical scavenger in the DPPH method. The antioxidant potential of representative compounds 5a and 5g was further confirmed by TEAC and ORAC assays. Cell viability assays revealed that while the promising compounds 5a and 5g had no significant toxicity against HepG2 and NIH3T3 cells, they potently protected HepG2 cells against H2O2-induced oxidative damage at low concentrations. Furthermore, spectroscopic studies with different biometals demonstrated that 5g was able to interact with Cu2+ to form a 1:1 complex.

Discovery of benzylthio analogs of fluconazole as potent antifungal agents.

AIM: A new series of triazole alcohol antifungals 8a-j were designed by introducing benzylthio functionality on one triazole ring of fluconazole. RESULTS: The antifungal activity evaluation of target compounds against 16 Candida isolates indicated that all compounds with MIC values of 0.063-1 µg/ml had better profile of activity in respect to fluconazole (MICs = 0.5-4 µg/ml) against fluconazole-susceptible isolates. In particular, the representative compounds 8b and 8e were also active against fluconazole-resistant isolates of Candida albicans and Candida parapsilosis (MICs = 0.063-16 µg/ml). Cytotoxicity assay against Hep-G2 and NIH-3T3 cell lines revealed that these compounds can display potent antifungal activity at noncytotoxic concentrations. CONCLUSION: The prototype compound 8b could be considered as a new lead for design and development of potent antifungal agents. [Formula: see text].

Design, synthesis, in vivo and in silico evaluation of phenacyl triazole hydrazones as new anticonvulsant agents.

A series of phenacyl triazole hydrazones 3 have been designed based on the hybridization of (arylalkly)triazole and aroyl hydrazone scaffolds as new anticonvulsant agents. The target compounds 3 were easily synthesized from appropriate phenacyl triazoles and aryl acid hydrazides and characterized by IR, NMR and Mass spectroscopy. The in vivo anticonvulsant evaluation of synthesized compounds by using MES and PTZ tests revealed that they are more effective in MES model respect to PTZ test. All compounds showed 33-100% protection against MES-induced seizures at the dose of 100 mg/kg. However, the isonicotinic acid hydrazide derivative 3h showed the best profile of activity in both models. Molecular docking studies of compound 3h with different targets (NMDA, AMPA, GABAA and sodium channel), postulated that the compound acts mainly via GABAA receptors. In silico molecular properties predictions indicated that all compounds have favourable oral bioavailability and BBB permeability.

In Vitro Activities of Novel Azole Compounds ATTAF-1 and ATTAF-2 against Fluconazole-Susceptible and -Resistant Isolates of Candida Species.

The in vitro activities of two novel azole compounds (aryl-1,2,4-triazol-3-ylthio analogues of fluconazole [ATTAFs]) and five comparator antifungal agents against 52 clinical Candida isolates from 5 different species were determined. The novel azole compounds had the lowest geometric mean MICs, followed by fluconazole. Moreover, combinations of these compounds with fluconazole exhibited synergistic effects against fluconazole-susceptible (22 of 23 isolates), fluconazole-susceptible dose-dependent (10 of 13 isolates), and fluconazole-resistant (1 of 16 isolates) Candida isolates.

Synthesis and biological evaluation of fluconazole analogs with triazole-modified scaffold as potent antifungal agents.

In order to find new azole antifungals, we have recently designed a series of triazole alcohols in which one of the 1,2,4-triazol-1-yl group in fluconazole structure has been replaced with 4-amino-5-aryl-3-mercapto-1,2,4-triazole motif. In this paper, we focused on the structural refinement of the primary lead, by removing the amino group from the structure to achieve 5-aryl-3-mercapto-1,2,4-triazole derivatives 10a-i and 11a-i. The in vitro antifungal susceptibility testing of title compounds demonstrated that most compounds had potent inhibitory activity against Candida species. Among them, 5-(2,4-dichlorophenyl)triazole analogs 10h and 11h with MIC values of <0.01 to 0.5µg/mL were 4-256 times more potent than fluconazole against Candida species.

Novel triazole alcohol antifungals derived from fluconazole: design, synthesis, and biological activity.

A series of new triazole alcohol antifungals were designed by replacing one of the triazolyl moiety from fluconazole with a distinct 4-amino-3-mercapto-1,2,4-triazole motif, which is found in some antimicrobial agents. The antimicrobial susceptibility testing of target compounds demonstrated that the direct analogs of fluconazole (difluorophenethyl-triazoles) were less active against fungi, while compound 10h containing dichloro substitutions on both phenyl rings of the molecule had potent activity against yeasts including Candida albicans (four strains) and Cryptococcus neoformans (MICs = 2-8 µg/mL). Also, compound 10h was active against Candida parapsilosis, Epidermophyton floccosum, and Trichophyton mentagrophytes, while it showed no activity against Gram-positive and Gram-negative bacteria. Finally, a molecular docking study suggested that compound 10h interacts suitably with lanosterol 14α-demethylase, which is the key enzyme in ergosterol biosynthesis.