Chemical Synthesis and Hemi-Synthesis of Novel Benzimidazole Derivatives Using Microwave-Assisted Process: Chemical Characterization, Bioactivities and Molecular Docking

Benzimidazole derivatives represent a class of heterocyclic compounds that exhibit a wide range of pharmaceutical properties. The present study aimed to investigate the in-vitro antioxidant and antimicrobial activities of newly synthesized benzimidazole derivatives. Compound 1b (2-(1H-1,3-benzodiazol-2-yl) phenol) was synthesized by reacting o-phenylenediamine (OPA) with chemical salicylaldehyde, while compounds 2b (2-(2-[(1E)-2-phenylethenyl]-1H-1,3-benzodiazole) and 3b (2-[(1E)-2,6-dimethylhepta-1,5-dien-1-yl]-1H-1,3-benzodiazole) were obtained through a hemi-synthesis process of, respectively, the cinnamon (cinnamaldehyde, 90.54%) and lemongrass (cis-citral, 43.9%) essential oils previously characterized by GC/MS. Compounds 4b (2-phenyl-1H-benzimidazole) and 5b (5-(1H-benzimidazol-2-yl)benzene-1,2,3-triol) were synthesized with a click chemistry method by reacting the OPA with benzoic acid and gallic acid directly in ethanol under microwave irradiation (MW) at 400 MHz. The structure/purity of the synthesized compounds was clarified by spectroscopy, ATR-FTIR and NMR 1H. Compounds 1b–5b were screened for their antioxidant activity by using four complementary in-vitro assays: DPPH scavenging activity, ferric ion reducing power, β-carotene bleaching inhibition, and Thiobarbituric Acid Reactive Substance Assay (TBARS) formation inhibition. All the tested compounds showed antioxidant potential, with varying performance. Antimicrobial activity was investigated against American Type Culture Collection (ATCC) strains (three Gram- bacteria: Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa; one Gram+ bacteria: Staphylococcus aureus, and one yeast strain: Candida albicans) through the determination of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) by using the microdilution method and rapid colorimetric test of p-iodonitrotetrazolium chloride (INT). Compound 5b exhibited the highest potential, especially against S. aureus (MIC = 0.156 mg·mL−1) followed by S. typhi and C. albicans (MIC = 0.3125 mg·mL−1) and then by E. coli and P. aeruginosa. Compound 1b also showed great potential against S. aureus and C. albicans (MIC ˂ 0.3125 mg·mL−1), followed by E. coli and S. typhi (MIC = 0.3125 mg·mL−1) and P. aeruginosa (MIC = 0.625 mg·mL−1). Further molecular docking was conducted using AutoDock Vina 1.1.2 software on S. aureus thymidylate kinase (TMK) protein to highlight the structure–activity relationship of the potent molecules.

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SYNTHESIS, CHARACTERIZATION AND IN VITRO ANTIMICROBIAL EVALUATION OF SOME NOVEL BENZIMIDAZOLE DERIVATIVES BEARING HYDRAZONE MOIETY

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10s4.21328 ◽

2017 ◽

Vol 10 (16) ◽

pp. 1

Author(s):

Jayanta Sarma ◽

Gurvinder Singh ◽

Mukta Gupta ◽

Reena Gupta ◽

Bhupinder Kapoor

Keyword(s):

Antibacterial Properties ◽

Antimicrobial Properties ◽

Aromatic Aldehydes ◽

Antibacterial Activities ◽

Antimicrobial Activities ◽

Benzimidazole Derivatives ◽

E Coli ◽

Antimicrobial Evaluation ◽

Antibacterial Potential

Objective: The synthesis of novel benzimidazole-hydrazone derivatives has been carried out based on the previous findings that both these pharmacophores possess potent antimicrobial activities. The antibacterial properties of synthesized derivatives were screened against both Gram-positive and Gram-negative bacteria.Methods: O-phenylenediamine on condensation with substituted aromatic acids in polyphosphoric acid gave benzimidazole nucleus which on reaction with ethyl chloroacetate and hydrazine hydrate in two different steps resulted in the formation of substituted acetohydrazides. The targeted compounds 6a-l were synthesized by reaction of substituted acetohydrazides with aromatic aldehydes and screened for their antibacterial potential by cup-plate method.Results: The synthesized benzimidazole-hydrazones exhibited moderate to strong antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The compounds 6a-6f were found to be most effective against S. aureus, E. coli, and P. aeruginosa. Among all the synthesized compounds, the zone of inhibition of 6f in highest concentration, i.e., 100 μg/ml were found to be >31 mm against all the stains of bacteria.Conclusion: The antibacterial results revealed that the synthetized derivatives have significant antimicrobial properties and further structure activity relationship studies may develop more potent and less toxic molecules.

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Molecular Docking and Quantum Studies of Lawsone Dimers Derivatives: New Investigation of Antioxidant Behavior and Antifungal Activity

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666191223092723 ◽

2020 ◽

Vol 20 (3) ◽

pp. 182-191 ◽

Cited By ~ 1

Author(s):

Aldo S. de Oliveira ◽

David L. Palomino-Salcedo ◽

Eduardo Zapp ◽

Daniela Brondani ◽

Thaynara D. Hoppe ◽

...

Keyword(s):

Molecular Docking ◽

Reducing Power ◽

Public Health Problem ◽

Resistance Mechanisms ◽

Docking Studies ◽

Fungal Species ◽

Antioxidant Potential ◽

In Vitro Assays ◽

Major Public Health Problem

Background: In general, fungal species are characterized by their opportunistic character and can trigger various infections in immunocompromised hosts. The emergence of infections associated with high mortality rates is due to the resistance mechanisms that these species develop. Methods: This phenomenon of resistance denotes the need for the development of new and effective therapeutic approaches. In this paper, we report the investigation of the antioxidant and antifungal behavior of dimeric naphthoquinones derived from lawsone whose antimicrobial and antioxidant potential has been reported in the literature. Results: Seven fungal strains were tested, and the antioxidant potential was tested using the combination of the methodologies: reducing power, total antioxidant capacity and cyclic voltammetry. Molecular docking studies (PDB ID 5V5Z and 1EA1) were conducted which allowed the derivation of structureactivity relationships (SAR). Compound 1-i, derived from 3-methylfuran-2-carbaldehyde showed the highest antifungal potential with an emphasis on the inhibition of Candida albicans species (MIC = 0.5 µg/mL) and the highest antioxidant potential. Conclusion: A combination of molecular modeling data and in vitro assays can help to find new solutions to this major public health problem.

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Biotransformation of Flavonoids Improves Antimicrobial and Anti-Breast Cancer Activities In Vitro

Foods ◽

10.3390/foods10102367 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2367

Author(s):

Yanpeng Hao ◽

Zuchen Wei ◽

Zhi Wang ◽

Guiying Li ◽

Yang Yao ◽

...

Keyword(s):

Breast Cancer ◽

Antimicrobial Activities ◽

Inhibitory Effect ◽

Bioactive Substances ◽

Antiproliferative Effects ◽

E Coli ◽

Wide Range ◽

Ic50 Values ◽

Range Of Functions

Coarse cereals are rich in flavonoids, which are bioactive substances with a wide range of functions. Biotransformation is considered an emerging approach to methylate flavonoids, displaying prominent regio- and stereoselectivity. In the current study, liquiritigenin, naringenin, and hesperidin flavonoids were biotransformed using O-methyltransferases that were heterologously expressed in Saccharomyces cerevisiae BJ5464-NpgA. Nuclear magnetic resonance (NMR) spectroscopy was used together with high-resolution mass spectroscopy analysis to determine the structures of the resulting methylated transformants, and their antimicrobial and antiproliferation activities were also characterized. Among the five methylated flavonoids obtained, 7-methoxy-liquiritigenin had the strongest inhibitory effect on Candida albicans SC5314 (C. albicans SC5314), Staphylococcus aureus ATCC6538 (S. aureus ATCC6538), and Escherichia coli ATCC25922 (E. coli ATCC25922), which increased 7.65-, 1.49-, and 0.54-fold in comparison to the values of their unmethylated counterparts at 200, 250, and 400 μM, respectively. The results suggest that 3’-methoxyhesperetin showed the best antiproliferative activity against MCF-7 cells with IC50 values of 10.45 ± 0.45 µM, which was an increase of more than 14.35-fold compared to that of hesperetin. These results indicate that methylation enhances the antimicrobial activities and antiproliferative effects of flavonoids. The current study provides an experimental basis for further research on flavonoids as well as flavonoid-containing crops in the development of antimicrobial and anti-breast cancer drugs in addition to supplementary and health foods. The biotransformation method is ideal, as it represents a means for the sustainable production of bioactive flavonoids.

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The Molecular and Enzyme Kinetic Basis for Altered Activity of Three Cytochrome P450 2C19 Variants Found in the Chinese Population

Current Molecular Pharmacology ◽

10.2174/1874467212666191111110429 ◽

2020 ◽

Vol 13 (3) ◽

pp. 233-244

Author(s):

Amelia Nathania Dong ◽

Nafees Ahemad ◽

Yan Pan ◽

Uma Devi Palanisamy ◽

Beow Chin Yiap ◽

...

Keyword(s):

Cytochrome P450 ◽

Molecular Docking ◽

Active Site ◽

Chinese Population ◽

Accessible Surface Area ◽

Solvent Accessible Surface Area ◽

In Vitro Assays ◽

Access Channel ◽

Cytochrome P450 2C19

Background: There is a large inter-individual variation in cytochrome P450 2C19 (CYP2C19) activity. The variability can be caused by the genetic polymorphism of CYP2C19 gene. This study aimed to investigate the molecular and kinetics basis for activity changes in three alleles including CYP2C19*23, CYP2C19*24 and CYP2C19*25found in the Chinese population. Methods: The three variants expressed by bacteria were investigated using substrate (omeprazole and 3- cyano-7-ethoxycoumarin[CEC]) and inhibitor (ketoconazole, fluoxetine, sertraline and loratadine) probes in enzyme assays along with molecular docking. Results: All alleles exhibited very low enzyme activity and affinity towards omeprazole and CEC (6.1% or less in intrinsic clearance). The inhibition studies with the four inhibitors, however, suggested that mutations in different variants have a tendency to cause enhanced binding (reduced IC50 values). The enhanced binding could partially be explained by the lower polar solvent accessible surface area of the inhibitors relative to the substrates. Molecular docking indicated that G91R, R335Q and F448L, the unique mutations in the alleles, have caused slight alteration in the substrate access channel morphology and a more compact active site cavity hence affecting ligand access and binding. It is likely that these structural alterations in CYP2C19 proteins have caused ligand-specific alteration in catalytic and inhibitory specificities as observed in the in vitro assays. Conclusion: This study indicates that CYP2C19 variant selectivity for ligands was not solely governed by mutation-induced modifications in the active site architecture, but the intrinsic properties of the probe compounds also played a vital role.

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Synthesis and In Vitro Antimicrobial Evaluation of Photoactive Multi—Block Chalcone Conjugate Phthalimide and 1,8-Naphthalimide Novolacs

Polymers ◽

10.3390/polym13111859 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1859

Author(s):

Periyan Durairaju ◽

Chinnasamy Umarani ◽

Govindasami Periyasami ◽

Perumberkandigai Adikesavan Vivekanand ◽

Mostafizur Rahaman

Keyword(s):

Spectroscopic Analysis ◽

Photophysical Properties ◽

Gel Permeation Chromatography ◽

13C Nmr Spectroscopy ◽

Antimicrobial Activities ◽

Microbial Activities ◽

E Coli ◽

Molecular Weights ◽

Antimicrobial Evaluation

Herein we report new multiblock chalcone conjugate phthalimide and naphthalimide functionalized copolymers with a topologically novel architecture synthesis using nucleophilic substitution and polycondensation methodology. The structures of the synthesized novolacs were elucidated on the basis of their spectroscopic analysis including FTIR, 1H NMR, and 13C NMR spectroscopy. Further, the number-average and weight-average molecular weights of the novolac polymers were determined by gel permeation chromatography (GPC). We examined the solubility of the synthesized polymers in various organic solvents including CHCl3, CH3CN, THF, H2O, CH3OH, DMSO, and DMF and found they are insoluble in both methanol and water. The novolac polymers were evaluated for their photophysical properties and microbial activities. The investigation of the antimicrobial activities of these polymers reveals significant antimicrobial activity against the pathogens E. coli, S. aureus, C. albicans, and A. niger.

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Bound To Shock: Protection from Lethal Endotoxemic Shock by a Novel, Nontoxic, Alkylpolyamine Lipopolysaccharide Sequestrant

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00200-07 ◽

2007 ◽

Vol 51 (8) ◽

pp. 2811-2819 ◽

Cited By ~ 15

Author(s):

Diptesh Sil ◽

Anurupa Shrestha ◽

Matthew R. Kimbrell ◽

Thuan B. Nguyen ◽

Ashok K. Adisechan ◽

...

Keyword(s):

Polymyxin B ◽

In Vitro Assays ◽

Critically Ill Patient ◽

Peptide Antibiotic ◽

Outer Membranes ◽

Wide Range ◽

Endotoxemic Shock ◽

Inflammatory Processes ◽

Shock Protection

ABSTRACT Lipopolysaccharide (LPS), or endotoxin, a structural component of gram-negative bacterial outer membranes, plays a key role in the pathogenesis of septic shock, a syndrome of severe systemic inflammation which leads to multiple-system organ failure. Despite advances in antimicrobial chemotherapy, sepsis continues to be the commonest cause of death in the critically ill patient. This is attributable to the lack of therapeutic options that aim at limiting the exposure to the toxin and the prevention of subsequent downstream inflammatory processes. Polymyxin B (PMB), a peptide antibiotic, is a prototype small molecule that binds and neutralizes LPS toxicity. However, the antibiotic is too toxic for systemic use as an LPS sequestrant. Based on a nuclear magnetic resonance-derived model of polymyxin B-LPS complex, we had earlier identified the pharmacophore necessary for optimal recognition and neutralization of the toxin. Iterative cycles of pharmacophore-based ligand design and evaluation have yielded a synthetically easily accessible N 1,mono-alkyl-mono-homologated spermine derivative, DS-96. We have found that DS-96 binds LPS and neutralizes its toxicity with a potency indistinguishable from that of PMB in a wide range of in vitro assays, affords complete protection in a murine model of LPS-induced lethality, and is apparently nontoxic in vertebrate animal models.

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Discovery and Optimisation of Bacterial Nitroreductases for Use in Anti-Cancer Gene Therapy

10.26686/wgtn.16985503 ◽

2021 ◽

Author(s):

◽

Gareth Adrian Prosser

Keyword(s):

Dna Damage ◽

Mammalian Cells ◽

Excision Repair ◽

Alkylating Agents ◽

Dna Lesions ◽

Site Directed Mutagenesis ◽

In Vitro Assays ◽

E Coli ◽

Anti Cancer

<p>Nitroaromatic prodrugs are biologically inert compounds that are attractive candidates for anti-cancer therapy by virtue of their ability to be converted to potent DNA alkylating agents by nitroreductase (NTR) enzymes. In gene-directed enzyme-prodrug therapy (GDEPT), NTR-encoding therapeutic transgenes are delivered specifically to tumour cells, whereupon their expression confers host cell sensitivity to subsequent systemic administration of a nitroaromatic prodrug. The most well studied NTR-GDEPT system involves reduction of the aziridinyl dinitrobenzamide prodrug CB1954 by the Escherichia coli NTR NfsB. However, low affinity of this enzyme for CB1954 has so far limited the clinical efficacy of this GDEPT combination. The research described in this thesis has primarily sought to address this limitation through identification and optimisation of novel NTR enzymes with improved nitroaromatic prodrug reductase activity. Efficient assessment of NTR activity from large libraries of candidate enzymes requires a rapid and reliable screening system. An E. coli-based assay was developed to permit indirect assessment of relative rates of prodrug reduction by over-expressed NTRs via measurement of SOS response induction resulting from reduced prodrug-induced DNA damage. Using this assay in concert with other in vitro and in vivo tests, more than 50 native bacterial NTRs of diverse sequence and origin were assessed for their ability to reduce a panel of clinically attractive nitroaromatic prodrugs. Significantly, a number of NTRs were identified, particularly in the family of enzymes homologous to the native E. coli NTR NfsA, which displayed substantially improved activity over NfsB with CB1954 and other nitroaromatic prodrugs as substrates. This work also examined the roles of E. coli DNA damage repair pathways in processing of adducts induced by various nitroaromatic prodrugs. Of particular interest, nucleotide excision repair was found to be important in the processing of DNA lesions caused by 4-, but not 2-nitro group reduction products of CB1954, which suggests that there are some parallels in the mechanisms of CB1954 adduct repair in E. coli and mammalian cells. Finally, a lead NTR candidate, YcnD from Bacillus subtilis, was selected for further activity improvement through site-directed mutagenesis of active site residues. Using SOS screening, a double-site mutant was identified with 2.5-fold improved activity over the wildtype enzyme in metabolism of the novel dinitrobenzamide mustard prodrug PR-104A. In conclusion, novel NTRs with substantially improved nitroaromatic prodrug reducing activity over previously documented enzymes were identified and characterised. These results hold significance not only for the field of NTR-GDEPT, but also for other biotechnological applications in which NTRs are becoming increasingly significant, including developmental studies, antibiotic discovery and bioremediation. Furthermore, the in vitro assays developed in this study have potential utility in the discovery and evolution of other GDEPT-relevant enzymes whose prodrug metabolism is associated with genotoxicity.</p>

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Preventive antimicrobial action and tissue architecture ameliorations of Bacillus subtilis in challenged broilers

Veterinary World ◽

10.14202/vetworld.2021.523-536 ◽

2021 ◽

Vol 14 (2) ◽

pp. 523-536

Author(s):

Essam S. Soliman ◽

Rania T. Hamad ◽

Mona S. Abdallah

Keyword(s):

Bacillus Subtilis ◽

Broiler Chickens ◽

Trichophyton Mentagrophytes ◽

Antimicrobial Activities ◽

Lymphoid Hyperplasia ◽

Bursa Of Fabricius ◽

Tissue Architecture ◽

E Coli

Background and Aim: Probiotics improve intestinal balance through bacterial antagonism and competitive exclusion. This study aimed to investigate the in vitro antimicrobial activity, as well as the in vivo preventive, immunological, productive, and histopathological modifications produced by probiotic Bacillus subtilis. Materials and Methods: The in vitro antimicrobial activities of B. subtilis (5×106 CFU/g; 0.5, 1.0*, 1.5, and 2.0 g/L) were tested against Escherichia coli O157: H7, Salmonella Typhimurium, Candida albicans, and Trichophyton mentagrophytes after exposure times of 0.25, 0.5, 1, and 2 h using minimal inhibitory concentration procedures. A total of 320 1-day-old female Ross broiler chickens were divided into five groups. Four out of the five groups were supplemented with 0.5, 1.0*, 1.5, and 2.0 g/L probiotic B. subtilis from the age of 1 day old. Supplemented 14-day-old broiler chickens were challenged with only E. coli O157: H7 (4.5×1012 CFU/mL) and S. Typhimurium (1.2×107 CFU/mL). A total of 2461 samples (256 microbial-probiotic mixtures, 315 sera, 315 duodenal swabs, and 1575 organs) were collected. Results: The in vitro results revealed highly significant (p<0.001) killing rates at all-time points in 2.0 g/L B. subtilis: 99.9%, 90.0%, 95.6%, and 98.8% against E. coli, S. Typhimurium, C. albicans, and T. mentagrophytes, respectively. Broilers supplemented with 1.5 and 2.0 g/L B. subtilis revealed highly significant increases (p<0.01) in body weights, weight gains, carcass weights, edible organs' weights, immune organs' weights, biochemical profile, and immunoglobulin concentrations, as well as highly significant declines (p<0.01) in total bacterial, Enterobacteriaceae, and Salmonella counts. Histopathological photomicrographs revealed pronounced improvements and near-normal pictures of the livers and hearts of broilers with lymphoid hyperplasia in the bursa of Fabricius, thymus, and spleen after supplementation with 2.0 g/L B. subtilis. Conclusion: The studies revealed that 1.5-2.0 g of probiotic B. subtilis at a concentration of 5×106 CFU/g/L water was able to improve performance, enhance immunity, and tissue architecture, and produce direct antimicrobial actions.

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