In vitro and in vivo activity of a novel oxamide-hydrazone hybrid derivative against triple-negative breast cancer.

Triple-negative breast cancer is a subtype of breast cancer with poor clinical outcome, and currently, no effective targeted therapies are available. Since cancer develops owing to deregulation of apoptosis, employing therapeutic strategies with the ability to target the molecules involved in apoptosis induction would provide a valid approach to hinder tumor progression. Hydrazide-hydrazones and oxamide molecules are the subject of intense studies due to their anticancer effects via apoptosis induction. In the present study, we attempted to elucidate the mechanism of action of a synthesized compound (compound A) in inducing cell death. Annexin/PI and Western blotting analyses, DAPI staining, mitochondrial membrane potential probe, and flow cytometry were applied for the in vitro evaluations. 4T1 syngeneic mouse model and immunohistochemistry were used for the in vivo assessments. Compound A caused cell death by inducing apoptosis in MDA-MB-231 cells in a mitochondrial-dependent manner at high concentrations after 72 h of incubation. Compound A also impeded tumor growth in a 4T1 syngeneic mouse model as evidenced by hematoxylin and eosin staining of the tumors. Furthermore, it significantly diminished the expression of pro-caspase-3, Ki67, and CD31 markers in the tumor sections. Conclusively, this study for the first time reports the anti-cancer efficacy of compound A in both in vitro and in vivo models and its potential in the treatment of triple-negative breast cancer.

In-silico activity prediction and docking studies of some flavonol derivatives as anti-prostate cancer agents based on Monte Carlo optimization.

The QSAR models are employed to predict the anti-proliferative activity of 81 derivatives of flavonol against prostate cancer using the Monte Carlo algorithm based on the index of ideality of correlation (IIC) criterion. CORAL software is employed to design the QSAR models. The molecular structures of flavonols are demonstrated using the simplified molecular input line entry system (SMILES) notation. The models are developed with the hybrid optimal descriptors i.e. using both SMILES and hydrogen-suppressed molecular graph (HSG). The QSAR model developed for split 3 is selected as a prominent model ([Formula: see text]= 0.727, [Formula: see text]= 0.628, [Formula: see text]= 0.642, and [Formula: see text]=0.615). The model is interpreted mechanistically by identifying the characteristics responsible for the promoter of the increase or decrease. The structural attributes as promoters of increase of pIC50 were aliphatic carbon atom connected to double-bound (C…=…, aliphatic oxygen atom connected to aliphatic carbon (O…C…), branching on aromatic ring (c…(…), and aliphatic nitrogen (N…). The pIC50 of eight natural flavonols with pIC50 more than 4.0, were predicted by the best model. The molecular docking is also performed for natural flavonols on the PC-3 cell line using the protein (PDB: 3RUK).

QSAR and molecular docking studies of isatin and indole derivatives as SARS 3CLpro inhibitors.

The 3C-like protease (3CLpro), known as the main protease of SARS-COV, plays a vital role in the viral replication cycle and is a critical target for the development of SARS inhibitor. Comparative sequence analysis has shown that the 3CLpro of two coronaviruses, SARS-CoV-2 and SARS-CoV, show high structural similarity, and several common features are shared among the substrates of 3CLpro in different coronaviruses. The goal of this study is the development of validated QSAR models by CORAL software and Monte Carlo optimization to predict the inhibitory activity of 81 isatin and indole-based compounds against SARS CoV 3CLpro. The models were built using a newer objective function optimization of this software, known as the index of ideality correlation (IIC), which provides favorable results. The entire set of molecules was randomly divided into four sets including: active training, passive training, calibration and validation sets. The optimal descriptors were selected from the hybrid model by combining SMILES and hydrogen suppressed graph (HSG) based on the objective function. According to the model interpretation results, eight synthesized compounds were extracted and introduced from the ChEMBL database as good SARS CoV 3CLpro inhibitor. Also, the activity of the introduced molecules further was supported by docking studies using 3CLpro of both SARS-COV-1 and SARS-COV-2. Based on the results of ADMET and OPE study, compounds CHEMBL4458417 and CHEMBL4565907 both containing an indole scaffold with the positive values of drug-likeness and the highest drug-score can be introduced as selected leads.

Synthesis of oxamide-hydrazone hybrid derivatives as potential anticancer agents.

Background and purpose: Considering various studies implying anticancer activity of the hydrazone and oxamide derivatives through different mechanisms such as kinases and calpain inhibition, herein, we report the synthesis, characterization, and evaluation of the antiproliferative effect of a series of hydrazones bearing oxamide moiety compounds (7a-7n) against a panel of cancer cell lines to explore a novel and promising anticancer agent (7k). Experimental approach: Chemical structures of the synthesized compounds were confirmed by FTIR, 1H-NMR, 13C-NMR, and mass spectra. The antiproliferative activity and cell cycle progression of the target compound were investigated using the MTT assay and flow cytometry. Findings/Results: Compound 7k with 2-hydroxybenzylidene structure was found to have a significant in vitro anti-proliferative influence on MDA-MB-231 (human adenocarcinoma breast cancer) and 4T1 (mouse mammary tumor) cells as the model of triple-negative breast cancer, with the IC50-72h values of 7.73 ± 1.05 and 1.82 ± 1.14 µM, respectively. Following 72-h incubation with compound 7k, it caused MDA-MB-231 cell death through G1/S cell cycle arrest at high concentrations (12 and 16 µM). Conclusion and implications: Conclusively, this study for the first time reports the anti-proliferative efficacy of compound 7k possessing 2-hydroxyphenyl moiety, which may serve as a potent candidate in triple-negative breast cancer treatment.

Design and synthesis of novel ureido and thioureido conjugated hydrazone derivatives with potent anticancer activity.

BACKGROUND: Compounds possessing urea/thiourea moiety have a wide range of biological properties including anticancer activity. On the other hand, taking advantage of the low toxicity and structural diversity of hydrazone derivatives, they are presently being considered for designing chemical compounds with hydrazone moiety in the field of cancer treatment. With this in mind, a series of novel ureido/thioureido derivatives possessing a hydrazone moiety bearing nitro and chloro substituents (4a-4i) have been designed, synthesized, characterized and evaluated for their in vitro cytotoxic effect on HT-29 human colon carcinoma and HepG2 hepatocarcinoma cell lines. RESULTS: Two compounds (4c and 4e) having the chloro phenylurea group hybridized with phenyl hydrazone bearing nitro or chloro moieties demonstrated potent anticancer effect with the IC50 values between 2.2 and 4.8 µM at 72 h. The mechanism of action of compound 4c was revealed in hepatocellular carcinoma cells as an inducer of apoptosis in a caspase-independent pathway. CONCLUSION: Taken together, the current work presented compound 4c as a potential lead compound in developing future hepatocellular carcinoma chemotherapy drugs. METHODS: The compounds were synthesized and then characterized by physical and spectral data (FT-IR, 1H-NMR, 13C-NMR, Mass). The anticancer activity was assessed using MTT assay, flowcytometry, annexin-V, DAPI staining and Western blot analysis.

Synthesis of new 2-(5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-ylimino)thiazolidin-4-one derivatives as anti-MRSA and anti-H. pylori agents.

In this work, we have synthesized twenty five new 2-(5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-ylimino)thiazolidin-4-one derivatives bearing an aryl or heteroaryl methylene group on position 5 of thiazolidinone and evaluated their antimicrobial activity against Gram-positive and -negative bacteria as well as three metronidazole resistant Helicobacter pylori strains. Most of the compounds were very potent towards tested Gram-positive bacteria and showed an antibacterial efficacy substantially greater than ampicillin as the reference drug. However, no effectiveness was observed for the Gram-negative microorganisms. The compounds 9, 20 and 29 exhibited strong antimicrobial activity against Helicobacter pylori strains (inhibition zone > 30 mm) in 100 µg/disc and (inhibition zone > 20 mm) in 50 µg/disc. Taking these findings together, it seems that these potent antibacterial derivatives could be considered as promising agents for developing new anti-infectious drugs against microorganisms resistant to currently available antibiotics.

SMILES-based QSAR and molecular docking study of xanthone derivatives as α-glucosidase inhibitors.

Increasing diabetic population is one of the major health concerns all over the world. Inhibition of α-glucosidase is a clinically proved and attractive strategy to manage diabetes. In this study, robust and reliable QSAR models to predict α-glucosidase inhibitory potential of xanthone derivatives are developed by the Monte Carlo technique. The chemical structures are represented by SMILES notation without any 3D-optimization. The significance of the index of ideality correlation (IIC) with applicability domain (AD) is also studied in depth. The models developed using CORAL software by considering IIC criteria are found to be statistically more significant and robust than simple balance of correlation. The QSAR models are validated by both internal and external validation methods. The promoters of increase and decrease of activity are also extracted and interpreted in detail. The interpretation of developed models explains the role of different structural attributes in predicting the pIC50 of xanthone derivatives as α-glucosidase inhibitors. Based on the results of model interpretation, modifications are done on some xanthone derivatives and 15 new molecules are designed. The α-glucosidase inhibitory activity of novel molecules is further supported by docking studies.

DFT based QSAR study on quinolone-triazole derivatives as antibacterial agents.

QSAR modeling was performed on 39 quinolone-triazole derivatives against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacteria. The molecular structures were optimized using the DFT/B3LYP method and 6-31 G basis set. Molecular descriptors were extracted using quantum mechanical calculations. The hierarchical cluster analysis was performed for a rational subset division. The initial dataset was divided into calibration and validation sets, and modeling was done by stepwise MLR method for each of the two bacteria. Internal and external validation methods confirmed the robustness and predictability of the obtained models. According to the obtained model for S. aureus (R2 = 0.889, R2ext = 0.938, Q2LOO = 0.853), the four descriptors- partial atomic charges for the N1 atom in triazole and C7 of the quinolone nucleus, 4-carbonyl bond length, and 13C-NMR chemical shift of 3-carboxylic acid- were found to be the descriptors controlling the activity. According to the obtained model for P. aeruginosa (R2 = 0.957, R2ext = 0.923, Q2LOO = 0.909), the O atom's partial charge in carbonyl, LUMO-HOMO energy gap, and logP were found to be the descriptors having the highest correlation with the antibacterial activity. Finally, some new compounds with higher activities were designed and proposed.

Design, synthesis, and preliminary pharmacological evaluation of novel thiazolidinone derivatives as potential benzodiazepine agonists.

Thiazolidinones are well-known heterocycles that demonstrate promising biological effects such as anticonvulsant activity. Hybridization of these chemicals with scaffold, which has necessary pharmacophores for binding to the benzodiazepine receptors, can prompt a novel structure possessing extensive anticonvulsant effects. In this study, novel derivatives of thiazolidinone as new benzodiazepine agonists were designed, synthesized, and biologically evaluated. Compound 5h, 4-chloro-2-(2-fluorophenoxy)-N-(4-oxo-2-(p-tolyl)thiazolidin-3-yl)benzamide, exhibited considerable anticonvulsant activity, proper sedative-hypnotic effect, no memory impairment, and no muscle relaxant effect. The pharmacological effects of the designed compounds were antagonized by flumazenil, which confirmed the benzodiazepine receptors' involvement in their biological effects. Based on in silico calculations of ADME properties of our novel compounds, they could be active oral agents potentially. In this study, we designed novel structures by the hybridization of thiazolidinone moiety with scaffold which has necessary pharmacophores for binding to the benzodiazepine receptors. The results are very promising for developing new lead compounds as benzodiazepine agonists possess anticonvulsant effects.

Design and synthesis of novel 4-thiazolidinone derivatives with promising anti-breast cancer activity: Synthesis, characterization, in vitro and in vivo results.

Novel lead compounds as anticancer agents with the ability to circumvent emerging drug resistance have recently gained a great deal of interest. Thiazolidinones are among such compounds with well-established biological activity in the field of oncology. Here, we designed, synthesized and characterized a series of thiazolidinone structures (8a-8k). The results of anti-proliferative assay led to the discovery of compound 8j with a high potent cytotoxic effect using colon, liver and breast cancer cells. Furthermore, MDA-MB-231 and 4T1 cell lines were used to represent triple negative breast cancer (TNBC). Next, a number of in vitro and in vivo evaluations were carried out to demonstrate the potential activity against TNBC and also elucidate the possible mechanism of cell death induction. Our in vitro outcomes exhibited an impressive anticancer activity for compound 8j toward MDA-MB-231 cells through inducing apoptosis and a remarkable anti-metastatic feature via suppressing MMP-9 expression as well. Consistently, the in vivo and immunohistopathologic evaluations demonstrated that this compound significantly inhibited the 4T1 induced tumor growth and its metastasis to the lung. Altogether, among numerous thiazolidinone derivatives, compound 8j might represent a promising anticancer agent for TNBC, which is a major concern in the developed and developing countries.

A novel hydrazide compound exerts anti-metastatic effect against breast cancer.

BACKGROUND: There are currently a number of barriers hindering the successful treatment of breast cancer, including the metastatic spread of cancer cells. In looking for new anticancer agents, we reported two novel hydrazide derivatives with anti-cancer activity in human breast cancer cells. The current study aims to explore the therapeutic potential of the most effective one, N'-((5-nitrothiophen-2-yl)methylene)-2-(phenylthio)benzohydrazide (compound B), on metastatic breast cancer, which is resistant to available chemotherapeutics. METHODS: 4T1 mammary carcinoma cells were inoculated into the fat pad mammary of 5-7-week-old female BALB/c mice and then the effective compound was intraperitoneally administered for 4 weeks. Proliferation index and angiogenesis in tumor and lung tissues were examined with immunohistochemistry. In vitro assessments were also carried out to evaluate the effect of the compound on invasion of MDA-MB-231 cells. RESULTS: Our results demonstrated that this effective derivative significantly inhibited invasion of MDA-MB-231 cells in vitro as shown by Matrigel assay and quantitative real-time method for MMP-9 expression after 48 h of treatment. Daily administration of the compound suppressed the growth of primary tumor and its metastasis to lung, which was confirmed by H&E experiment at a dose of 1 mg/kg in a well-known metastatic model of 4T1 breast cancer in syngeneic BALB/c mice. These outcomes were supported by the immunohistochemical examinations of the tumor and lung tissues of mice. Tumors and lungs in mice treated with the effective compound showed a reduced proliferation index and a smaller microvessel density compared to the control. CONCLUSION: This study highlights an anti-metastatic role for a novel hydrazide derivative in both in vitro and in vivo models of breast cancer.

Synthesis and Docking Study of Novel 4-Thiazolidinone Derivatives as Anti-Gram-positive and Anti-H. pylori Agents.

BACKGROUND: Bacterial resistance to the available antibiotics is a life threatening issue and researchers are trying to find new drugs to overcome this problem. Amongst the different structural classes, thiazolidinone-4-one, as a new effective pharmacophore against various bacteria, has been introduced. OBJECTIVE: A new series of 2-(5-(5-nitrothiophene-2-yl)-1,3,4-thiadiazole-2-ylimino)-5-arylidenethiazolidin- 4-one derivatives were designed and synthesized as new antibacterial agents. METHOD: Target compounds were synthesized during 5 steps and their in vitro antibacterial and anti-H. pylori activities were evaluated. The interaction of the most active derivatives with the probable targets was assessed by Auto Dock 4.2 Program. RESULTS: The results showed that the most potent compounds, 18, 22 and 23, displayed antibacterial activity versus S.aureus, S.epidermidis, B.cereus and B.subtilis (MIC, 1.56-12.5 µg/mL) and none of the derivatives were active on tested Gram-negative bacteria. Compound 12 in all considered doses and compounds 10, and 27 had strong anti-H. pylori activity (inhibition zone >20 mm) in 25 µg disc. Docking studies determined suitable interactions and affinity of potent compounds with bacterial MUR B and H. pylori urease enzymes. CONCLUSION: According to the results most of the derivatives are effective anti-bacterial agents and docking evaluation confirmed their possible mechanisms of actions as MURB and Urease inhibitors.

A novel hydrazide compound exerts anti-metastatic effect against breast cancer

BACKGROUND: There are currently a number of barriers hindering the successful treatment of breast cancer, including the metastatic spread of cancer cells. In looking for new anticancer agents, we reported two novel hydrazide derivatives with anti-cancer activity in human breast cancer cells. The current study aims to explore the therapeutic potential of the most effective one, N'-((5-nitrothiophen-2-yl)methylene)-2-(phenylthio)benzohydrazide (compound B), on metastatic breast cancer, which is resistant to available chemotherapeutics. METHODS: 4T1 mammary carcinoma cells were inoculated into the fat pad mammary of 5-7-week-old female BALB/c mice and then the effective compound was intraperitoneally administered for 4 weeks. Proliferation index and angiogenesis in tumor and lung tissues were examined with immunohistochemistry. In vitro assessments were also carried out to evaluate the effect of the compound on invasion of MDA-MB-231 cells. RESULTS: Our results demonstrated that this effective derivative significantly inhibited invasion of MDA-MB-231 cells in vitro as shown by Matrigel assay and quantitative real-time method for MMP-9 expression after 48 h of treatment. Daily administration of the compound suppressed the growth of primary tumor and its metastasis to lung, which was confirmed by H&E experiment at a dose of 1 mg/kg in a well-known metastatic model of 4T1 breast cancer in syngeneic BALB/c mice. These outcomes were supported by the immunohistochemical examinations of the tumor and lung tissues of mice. Tumors and lungs in mice treated with the effective compound showed a reduced proliferation index and a smaller microvessel density compared to the control. CONCLUSION: This study highlights an anti-metastatic role for a novel hydrazide derivative in both in vitro and in vivo models of breast cancer.

Novel 4-thiazolidinone derivatives as agonists of benzodiazepine receptors: Design, synthesis and pharmacological evaluation.

A new series of 4-chloro-N-(2-(substitutedphenyl)-4-oxothiazolidin-3-yl)-2-phenoxybenzamide derivatives were designed, synthesized and biologically evaluated as anticonvulsant agents. The designed compounds have the main essential functional groups for binding to the benzodiazepine receptors and 4-thiazolidinone ring as an anticonvulsant pharmacophore. Some of the new synthesized compounds showed considerable anticonvulsant activity in electroshock and pentylenetetrazole-induced lethal convulsion tests. Compound 5i, 4-chloro-N-(2-(4-methoxyphenyl)-4-oxothiazolidin-3-yl)-2-phenoxybenzamide, with the best activity was selected for evaluation of other benzodiazepine pharmacological effects. This compound induced significant sedative-hypnotic activity. However, it does not impair the learning and memory in the experimental condition. Flumazenil was able to antagonize the sedative-hypnotic and anticonvulsant effects of compound 5i indicating that benzodiazepine receptors are highly involved in the pharmacological properties of the novel compounds.

In vitro and in vivo assessments of two novel hydrazide compounds against breast cancer as well as mammary tumor cells.

PURPOSE: The hydrazide backbone is a well-known structural core system found in a broad range of biologically activated compounds. Among which, the compounds with anticancer activity have been cited in a number of studies. With this object in mind, we focused on the in vitro and in vivo anticancer potential of two novel hydrazide derivatives bearing furan or thiophen substituents (compounds 1 and 2). METHODS: The cytotoxic property was evaluated using MTT assay against MCF-7 human breast adenocarcinoma cell line, while the in vivo antitumor activity was investigated in BALB/c mice bearing 4T1 mammary carcinoma cells. Flow cytometry was used for cell cycle analysis, and detection of apoptosis was examined by Annexin-V-FLUOS/PI assay. Protein expression of Bax, Bcl-2 and procaspase-3 was estimated by Western blotting. RESULTS: Compounds 1 and 2 were found to be cytotoxic towards breast cancer cells presenting IC50 values of 0.7 and 0.18 µM, respectively, and selectivity over normal fibroblast cells. Our findings further indicated that 2 × IC50 concentrations of both compounds induce early stage apoptosis and increase percentage of sub-G1 population in MCF-7 cells at 48 h. An elevation in Bax/Bcl-2 ratio and caspase-3 cleavage suggested that apoptosis induced by the two compounds is through a caspase- and mitochondrial-dependent pathway. In the in vivo study, compounds 1 and 2 at doses of 10 and 1 mg/Kg/day, respectively, significantly hindered the growth of tumor after 3 weeks of i.p. administration, when compared to vehicle-treated mice. CONCLUSION: Collectively, the great potential exhibited by compound 2 could make it a promising chemotherapeutic candidate for human cancers, especially for breast cancer.

Arylhydrazone derivatives of naproxen as new analgesic and anti-inflammatory agents: Design, synthesis and molecular docking studies.

A series of new arylidenehydrazone derivatives of naproxen were synthesized and evaluated for their analgesic and anti-inflammatory activities. Some of the synthesized analogues showed comparable activities when compared against naproxen for their analgesic and anti-inflammatory properties. 2-(6-methoxy-2-naphthyl)-N'-[(pyridine-4-yl)methylene]propanoic acid hydrazide 4j was found to be the most active analgesic agent. 2-(6-methoxy-2-naphthyl)-N'-[4-nitrobenzylidene]propanoic acid hydrazide 4g showed highest anti-inflammatory activity in comparison to the naproxen. Molecular modeling study of the synthesized compounds suggested that the designed molecules were well located and bound to the COX-1 and COX-2 active sites. Compound 4g showed the highest selectivity for COX-2 (RCOX-2/COX-1=1.94) and higher affinity rather than naproxen in COX-2 active site (RCOX-2/naproxen=1.28). Moreover, the structural analyses confirmed that the E-ap rotamer is the preferred structure for the arylidenehydrazone derivatives.

In Vitro Anticancer Effects of Two New Potent Hydrazide Compounds on Leukemic Cells.

BACKGROUND: Chronic myeloid leukemia (CML), also recognized as chronic myelogenous leukemia, is initiated in some types of blood-forming cells of the bone marrow. The therapeutic approach to CML is usually chemotherapy; however, severe side effects and complications are major problems in the clinical research. Thus, recent efforts have focused on the search for compounds affecting apoptosis in this type of cancer. OBJECTIVE: In this study, in vitro anticancer activity of two compounds (A and B) consisting of a hydrazide backbone with nitro-thiophen and furan substituents was assessed against K562 cell line displaying certain levels of sensitivity to pro-apoptotic compounds. METHODS: The anticancer activity was assessed using MTT assay, flowcytometry, annexin-V and Western blot analysis. RESULTS: Compounds A and B were both active and revealed a remarkable in vitro cytotoxic effect showing IC50 values of 0.09 and 0.07 µM, respectively, after 72 h of treatment. A significant increase in annexin-V/PI staining, sub-G1 population and Bax/Bcl-2 ratio revealed the apoptotic cell death of compounds A- and B-treated K562 cells. CONCLUSION: The results presented here could be used as a first step for the development of powerful chemotherapeutic agents to treat leukemia.

A role for ATP-sensitive potassium channels in the anticonvulsant effects of triamterene in mice.

There are reports indicating that diuretics including chlorothiazide, furosemide, ethacrynic acid, amiloride and bumetanide can have anticonvulsant properties. Intracellular acidification appears to be a mechanism for the anticonvulsant action of some diuretics. This study was conducted to investigate whether or not triamterene, a K(+)-sparing diuretic, can generate protection against seizures induced by intravenous or intraperitoneal pentylenetetrazole (PTZ) models. And to see if, triamterene can withstand maximal electroshock seizure (MES) in mice. We also investigated to see if there is any connection between triamterene's anti-seizure effect and ATP-sensitive K(+) (KATP) channels. Five days triamterene oral administration (10, 20 and 40 mg/kg), significantly increased clonic seizure threshold which was induced by intravenous pentylenetetrazole. Triamterene (10, 20 and 40 mg/kg) treatment also increased the latency of clonic seizure and decreased its frequency in intraperitoneal PTZ model. Administration of triamterene (20 mg/kg) also decreased the incidence of tonic seizure in MES-induced seizure. Co-administration of a KATP sensitive channel blocker, glibenclamide, in the 6th day, 60 min before intravenous PTZ blocked triamterene's anticonvulsant effect. A KATP sensitive channel opener, diazoxide, enhanced triamterene's anti-seizure effect in both intravenous PTZ or MES seizure models. At the end, triamterene exerts anticonvulsant effect in 3 seizure models of mice including intravenous PTZ, intraperitoneal PTZ and MES. The anti-seizure effect of triamterene probably is induced through KATP channels.

Functional and structural changes of human erythrocyte catalase induced by cimetidine: proposed model of binding.

In erythrocyte, catalase plays an important role to protect cells from hydrogen peroxide toxicity. Hydrogen peroxide is a byproduct compound which is produced during metabolic pathway of cells. Cimetidine, a histamine H2 receptor antagonist, is used for gastrointestinal tract diseases and prevents the extra release of gastric acid. In this study, the effect of cimetidine on the activity of human erythrocyte catalase was investigated. Erythrocytes were broken by hypotonic solution. The supernatant was used for catalase assay and kinetics study. Lineweaver-Burk plot was performed to determine the type of inhibition. The kinetics data revealed that cimetidine inhibited the catalase activity by mixed inhibition. The IC50 (1.54 µM) and Ki (0.45 µM) values of cimetidine determined that the drug was bound to the enzyme with high affinity. Circular dichroism and fluorescence measurement showed that the binding of cimetidine to the enzyme affected the content of secondary structure of the enzyme as well as its conformational changes. Docking studies were carried out to detect the site in which the drug was bound to the enzyme. Molecular modeling and energy calculation of the binding showed that the cyanoguanidine group of the drug connected to Asp59 via two hydrogen bonds, while the imidazole group of the drug interacted with Phe64 in the enzyme by a hydrophobic interaction. In conclusion, cimetidine could bind to human erythrocyte catalase, and its interaction caused functional and conformational changes in the enzyme.

Synthesis, analgesic and anti-inflammatory activities of new methyl-imidazolyl-1,3,4-oxadiazoles and 1,2,4-triazoles.

BACKGROUND: Long-term clinical employment of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with significant side effects including gastrointestinal (GI) lesions and kidney toxicity. In this paper we designed and synthesized new imidazolyl-1,3,4-oxadiazoles and 1,2,4-triazoles by molecular hybridization of previously described anti-inflammatory compounds in the hope of obtaining new safer analgesic and anti-inflammatory agents. METHODS: The target structures were synthesized by preparation of 5-methyl-1H-imidazole-4-carboxylic acid ethyl ester 5. The reaction of hydrazine hydrate with this ester afforded the 5-methyl-1H-imidazole-4-carboxylic acid hydrazide 6 which was converted to target compounds 7-15 according to the known procedures. In silico toxicity risk assessment and drug likeness predictions were done, in order to consider the privileges of the synthesized structures as drug candidates. RESULTS AND DISCUSSION: The analgesic and anti-inflammatory profile of the synthesized compounds were evaluated by writhing and carrageenan induced rat paw edema tests respectively. Compounds 8, 9 and 11-13 and 15 were active analgesic agents and compounds 8, 9 and 11-13 showed significant anti-inflammatory response in comparison with control. Compounds 11 and 13 were screened for their ulcerogenic activities and none of them showed significant ulcerogenic activity. The active Compounds 11 and 12 showed the highest drug likeness and drug score. CONCLUSIONS: The analgesic and anti-inflammatory activities of title compounds were comparable to that of standard drug indomethacin with a safer profile of activity. The results revealed that both of oxadiazole and triazole scaffolds can be determined as pharmacophores. The in silico predictions and pharmacological evaluations showed that compounds 11 and 12 can be chosen as lead for further investigations.