Synthesis of novel conjugated benzofuran-triazine derivatives: Antimicrobial and in-silico molecular docking studies

Two new developments of antibacterial agents, a series of benzofuran-triazine based compounds (8a-8h) were designed and synthesized. The derivatives were prepared through conventional chemical reactions and structurally characterized with FT-IR, 1H and 13C NMR techniques. The antibacterial activity of the synthesized derivatives was assessed against gram-positive bacterial strains (Bacillus subtilis, and Staphylococcus aureus) and gram-negative bacterial strains (Salmonella entritidis and Escherichia coli). Compound 8e, with the MIC value of 125-32 μg/μl against all the examined strains of bacteria, was the most active antibacterial compound. The synthesized derivatives were also studied for docking to the binding sites of dihydrofolate reductase (DHFR) receptor which has a key role in drug resistance associated with bacterial infections. The synthesized compounds showed good interaction with the targets through hydrogen bonding and hydrophobic interactions. According to antibacterial and docking studies, compound 8e could be introduced as a candidate for development of antibacterial compounds.

Novel N-α-amino acid spacer-conjugated phthalimide-triazine derivatives: synthesis, antimicrobial and molecular docking studies

To design and develop novel antimicrobial agents, a series of phthalimide-triazine-based derivatives (6a-6e) were synthesized, characterized and evaluated for their potential antibacterial activities. The compounds were prepared through reaction of 6-phenyl-1,3,5-triazine-2,4-diamine with phthalimide moiety containing aliphatic amino acid. Structural analysis of the synthesized compounds was carried out by various characterization techniques such as FT-IR, ¹H and ¹³C-NMR and mass spectroscopy. After the confirmation of the structure, the antibacterial screening of the synthesized compounds was performed against two strains of Gram-positive (Staphylococcus aureus, and Bacillus subtilis) and two strains of Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria. The results of antimicrobial activity showed that compound 6d was the most active against all the tested strains of microorganisms with the MIC value 1.25 µg/µl. The synthesized compounds were docked into the binding sites of E. coli-DNA gyrase B and S. aureus-DNA gyrase complex to explore their theoretically binding mode and possible interactions of these ligands with these two targets. Docking study showed the importance of both hydrogen bonding and hydrophobic interactions as a key interaction with the targets. Based on the obtained results, the hybrid derivatives of triazine and phthalimide could be regarded as efficient candidates for further molecular developments of antimicrobial agents.

Evaluation of the antinociceptive effects of a selection of triazine derivatives in mice

Background

The authors showed in a previous study that some novel triazine derivatives had an anti-inflammatory effect. The present study was designed to evaluate the antinociceptive effect of five out of nine compounds including two vanillin-triazine (5c and 5d) and three phenylpyrazole-triazine (10a, 10b, 10e) derivatives which showed the best anti-inflammatory effect.

Methods

Male Swiss mice (25–30 g) were used. To assess the antinociceptive effect, acetic acid-writhing, formalin, and hot plate tests were used after intraperitoneal injection of each compound.

Results

All compounds significantly (P < 0.001) reduced acetic acid-induced writhing at tested doses (50, 100, and 200 mg/kg). Also, the percent inhibition of writhing in the acetic acid test showed that at the maximum tested dose of these compounds (200 mg/kg), the order of potencies is as follows 10b > 10a > 10e > 5d > 5c. In the formalin test, compounds 5d, 10a, and 10e showed an antinociceptive effect in the acute phase and all compounds were effective in the chronic phase. In the hot plate test, compounds 5c, 5d, and 10a demonstrated an antinociceptive effect.

Conclusions

The results clearly showed that both vanillin-triazine and phenylpyrazole-triazine derivatives had an antinociceptive effect. Also, some compounds which showed activity in the early phase of formalin test as well as in the hot plate test could control acute pain in addition to chronic or inflammatory pain.

Some novel hybrid quinazoline-based heterocycles as potent cytotoxic agents

BACKGROUND AND PURPOSE

In this study, some new cytotoxic hybrid structures were synthesized by combining pyrazolinone and imidazolinone rings with quinazoline pharmacophores.

EXPERIMENTAL APPROACH

The benzoxazinone, pyrazolo-quinazoline fused ring, and imidazolinone anchored quinazoline derivatives were synthesized by simple ring-opening, ring expansion, and ring closure strategies from oxazolones. The molecular docking studies of the final derivatives were accomplished on the epidermal growth factor receptor enzyme. The cytotoxic effect of the final compounds on the MCF-7 cell line was evaluated by MTT assay.

FINDINGS/RESULTS

The docking results confirmed the optimized electrostatic, H-bonding, and hydrophobic interactions of structures with the key residues of the active site (ΔGbin< -9Kcal/mol). The derivatives have been obtained in good yield and purity, and their structures were confirmed by different methods (FT-IR, 1H-NMR, 13C-NMR, and CHNS analysis). The IC50s of all final derivatives against the MCF-7 cell line were lower than 10 μM, and between all, the IXa from pyrazolo-quinazolinone class (IC50: 6.43 μM) with chlorine substitute was the most potent. Furthermore, all derivatives showed negligible cytotoxicity on HUVEC normal cell line which would be a great achievement for a novel cytotoxic agent.

CONCLUSION AND IMPLICATIONS

Based on the obtained results, pyrazolo[1,5-c] quinazolin-2-one series were more cytotoxic than imidazolinone methyl quinazoline-4(3H)-ones against MCF-7 cells. Chlorine substitute in the para position of the aromatic ring improved the cytotoxicity effect in both classes. It could be related to the polarizability of a chlorine atom and making better intermolecular interactions. Further pre-clinical evaluations are required for the promising synthesized cytotoxic compounds.

Facile and fast preparation of layered double hydroxide as a nanocarrier for ascorbic acid under ultrasonic irradiation

Background and purpose:

Layered double hydroxides (LDHs) as inorganic materials are being used in controlled release and drug delivery systems. These materials are more stable than conventional drug carriers. In this investigation, Mg/Al-ascorbic acid (ASA) LDH nanohybrid was synthesized by ultrasonic-assisted co-deposition techniques.

Experimental approach:

In this study, Mg/Al-LDH to adsorption of ASA anions from the alkaline solution was assembled by a facile coprecipitation technique. During this process, ultrasonic irradiation was used to increase the rate of ion exchange between LDH and ASA. The intercalated-layered structure was characterized by FT-IR spectroscopy, XRD, thermogravimetric analysis, field emission SEM, and TEM. ASA releasing from Mg/Al-ASA LDH nanohybrid was carried out in incubation sodium carbonate solution (0.5 M) at 35 °C using UV-Vis absorbance analysis at λ = 265 nm

Findings/Results:

The used techniques confirmed the structure of Mg/Al-LDH and indicated successful intercalation of ASA into the interlayer galleries of the LDH host. The obtained results also have shown that Mg/Al-ASA LDH nanohybrid was generated with an average diameter size of 25 nm and narrow size distribution. Analysis of the release profiles using several kinetic models suggested that the first-order rate model is the most appropriate for describing the release of ASA from Mg/Al-LDH which means the amount of drug released is proportional to the amount of remaining drug in the matrix. Thus, the amount of activity released tends to decrease in function of time.

Conclusion and implications:

The results showed that LDHs are good host materials to preserve the biomolecule and modify its release rate and bioavailability.

Synthesis, characterization, molecular docking, antimalarial, and antiproliferative activities of benzyloxy-4-oxopyridin benzoate derivatives

Background and purpose:

Malaria and cancer are two major health issues affecting millions of lives annually. Maltol complexes and derivatives have been extensively investigated as chemotherapeutic and antimalarial activities. In this study, the design, synthesis, biological activities, and docking study of a novel series of pyridinones derivatives were reported.

Experimental approach:

The chemical structures of synthesized compounds were approved by FTIR, ¹HNMR, ¹³CNMR, and mass spectroscopies. The antimalarial activity was evaluated through β-hematin inhibition assay and the cytotoxicity activities were evaluated against PC12 and fibroblast cell lines via MTT and cell uptake assays. To theoretically investigate the ability of compounds to inhibit hemozoin formation, the synthesized compounds were docked in a heme sheet to explore their binding mode and possible interactions.

Findings/Results:

β-Hematin inhibition assay showed acceptable activity for 7f, 7c, and 7d compounds and the molecular docking study showed 7h and 7f had effective interactions with the heme sheet. The cytotoxic study revealed compound 4b (IC₅₀ = 18 μM) was significantly more active against PC12 cells than docetaxel (IC₅₀ = 280 μM). The observations of cell uptake images were also shown both cell penetration and monitoring potential of synthesized compounds.

Conclusion and implications:

The compounds showed a moderate ability to inhibition of heme polymerization and also good interaction with heme through molecular docking was observed. Additionally, some of them have a good cytotoxic effect on the study2 cell line. So further study on these compounds can lead to compounds that can be considered as anti-malarial and/or anticancer agents.

Preparation and characterization of itraconazole loaded nanomicelles based on dextran-behenic acid for cutaneous leishmaniasis treatment

Cutaneous leishmaniasis is known as the most prevalent clinical form of leishmaniasis. It needs the development of new therapies due to the serious side-effects promoted by taking the current drugs. In the present study, dextran-behenic acid (DEX-BA) based nanomicelles were developed to direct the delivery of itraconazole (ITZ) to the macrophages and enhance its toxic effects against Leishmania parasites. DEX-BA was synthesized through the esterification of dextran with behenic acid. The critical micelle concentration of the newly developed conjugate was evaluated using pyrene as the fluorescent probe. The nanomicelles were generated by the dialysis method; then they were optimized by applying a Box-Behnken design. The effects of the dialysis temperature, polymer content, and sonication time on the characteristics of micelles were subsequently studied. Furthermore, in vitro efficacy against Leishmania major promastigotes and parasite-infected macrophages was evaluated. The optimized formulation showed the particle size of 195.16 ± 3.06 nm, the polydispersity index of 0.39 ± 0.01, the zeta potential of -16.29 ± 0.89 mV, the encapsulation efficiency % of 56.11 ± 4.9, and the release efficiency % of 51.29 ± 1.97. According to scanning electron microscopy, the nanomicelles were found to be nearly spherical in shape. ITZ-loaded nanomicelles showed the strongest anti-leishmanial activities when compared with the free ITZ and drug-free nanomicelles. It could be, therefore, concluded that ITZ-loaded nanomicelles might be useful as an alternative therapy for the treatment of cutaneous leishmania.

Biologically Active Heterocyclic Hybrids Based on Quinazolinone, Benzofuran and Imidazolium Moieties: Synthesis, Characterization, Cytotoxic and Antibacterial Evaluation

Cytotoxic and antimicrobial agents structurally based on quinazolinone, benzofuran and imidazole pharmacophores, have been designed and synthesized. Spectral (IR, ¹ H-NMR) and elemental analysis data established the structures of these novel 3-[1-(1-benzofuran-2-yl)-2-(4-oxoquinazolin-3(4H)-yl)ethyl]-1-methyl-1H-imidazol-3-ium chloride hybrid derivatives. All the synthesized compounds were evaluated for in vitro cytotoxicity and antimicrobial activities. Cytotoxic evaluation using MTT assay revealed that compounds 12c, 12g and 12i exhibited significant cytotoxicity with IC₅₀ values 1, 1, and 0.57 μm on this cell line, respectively. Biological activity of the synthesized compounds as antibacterial agent were also evaluated against three Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi), three Gram-positive (Staphylococcus aureus, Bacillus subtilis and Listeria monocitogenes) and one yeast-like fungi (Candida albicans) strains. All compounds 12a - 12i showed slightly higher activity against Gram-positive bacteria than the Gram-negative one. Among the nine new compounds screened, 3-[1-(5-bromo-1-benzofuran-2-yl)-2-(6-chloro-4-oxoquinazolin-3(4H)-yl)ethyl]-1-methyl-1H-imidazol-3-ium chloride (12e) has pronounced higher antimicrobial activity against all tested strains. These results demonstrated potential importance of molecular hybridization in the development of new lead molecules with major cytotoxicity and antimicrobial activity.

Quantum mechanical/molecular mechanical and docking study of the novel analogues based on hybridization of common pharmacophores as potential anti-breast cancer agents

In an attempt to identify some new potential leads as anti-breast cancer agents, novel hybrid compounds were designed by molecular hybridization approach. These derivatives were structurally derived from hybrid benzofuran–imidazole and quinazolinone derivatives, which had shown good cytotoxicity against the breast cancer cell line (MCF-7). Since aromatase enzyme (CYP19) is highly expressed in the MCF-7 cell line, the binding of these novel hybrid compounds to aromatase was investigated using the docking method. In this study, due to the positive charge on the imidazole ring of the designed ligands and also, the presence of heme iron in the active site of the enzyme, it was decided to optimize the ligand inside the protein to obtain more realistic atomic charges for it. Quantum mechanical/molecular mechanical (QM/MM) method was used to obtain more accurate atomic charges of ligand for docking calculations by considering the polarization effects of CYP19 on ligands. It was observed that the refitted charge improved the binding energy of the docked compounds. Also, the results showed that these novel hybrid compounds were adopted properly within the aromatase binding site, thereby suggesting that they could be potential inhibitors of aromatase. The main binding modes in these complexes were through hydrophobic and H bond interactions showing agreement with the basic physicochemical features of known anti aromatase compounds. Finally, the complex structures obtained from the docking study were used for single point QM/MM calculations to obtain more accurate electronic interaction energy, considering the electronic polarization of the ligand by its protein environment.

Benzofuran as a promising scaffold for the synthesis of antimicrobial and antibreast cancer agents: A review

Benzofuran as an important heterocyclic compound is extensively found in natural products as well as synthetic materials. Since benzofuran drivatives display a diverse array of pharmacological activities, an interest in developing new biologically active agents from benzofuran is still under consideration. This review highlights recent findings on biological activities of benzofuran derivatives as antimicrobial and antibreast cancer agents and lays emphasis on the importance of benzofurans as a major source for drug design and development.

Design of novel potential aromatase inhibitors via hybrid pharmacophore approach: docking improvement using the QM/MM method

QM/MM and docking methods were used for designing novel hybrid aromatase inhibitors incorporating benzofuran, imidazole and quinazolinone moieties.

Thermal, mechanical and optical transport properties of nanocomposite materials based on triethoxysilane-terminated polyimide and TiO2 nanoparticles

Novel polyimide/TiO₂ nanocomposites with good mechanical, optical and thermal properties were prepared by the incorporation of TiO₂ nanoparticles into silane terminated polyimide.

In situ thermal synthesis of novel polyimide nanocomposite films containing organo-modified layered double hydroxide: morphological, thermal and mechanical properties

An organic–inorganic hybrid compound comprised of a Zn/Al layered double hydroxide (LDH) intercalated with citric acid (LDH–CA) was dispersed in polyimide (PI) with an N-benzonitrile side group, through in situ polymerization.

Fabrication and characterization of novel highly transparent and organo-soluble poly(ether imide)s thin film for gas separation

New poly(ether imide)s with good solubility, film quality and thermal stability were synthesis for high-performance gas separation membrane by solution-casting.