Benzimidazole–ibuprofen/mesalamine conjugates: Potential candidates for multifactorial diseases

Design, classification, and adverse effects of NSAIDs: A review on recent advancements

Inflammation is a hallmark of many diseases, including cancer, neurodegenerative diseases like Alzheimer's, type II diabetes, rheumatoid arthritis, and asthma. Nonsteroidal anti-inflammatory drugs (NSAIDs) have been a cornerstone in the management of various inflammatory, pain, and fever-related conditions. As a result, NSAIDs have found their applications in new therapeutic areas. NSAIDs are known to act by inhibiting the cyclooxygenase (COX) pathway. In recent years, new strategies have been proposed to counter inflammation and develop safer COX inhibitors. This review discusses the design of new COX inhibitors, the derivatization of conventional NSAIDs, and their biological applications. The review also presents an integrated classification of NSAIDs incorporating both traditional chemical-based and function-based approaches, including a brief overview of the NSAIDs of natural origins. Additionally, the review addresses adverse effects associated with different NSAIDs, including effects associated with cardiovascular, renal, and hepatic complications emphasizing the need for the development of new and safer COX inhibitors.

Antiplasmodial activity, structure-activity relationship and studies on the action of novel benzimidazole derivatives

Malaria cases and deaths keep being excessively high every year. Some inroads gained in the last two decades have been eroded especially due to the surge of resistance to most antimalarials. The search for new molecules that can replace the ones currently in use cannot stop. In this report, the synthesis of benzimidazole derivatives guided by structure-activity parameters is presented. Thirty-six molecules obtained are analyzed according to their activity against P. falciparum HB3 strain based on the type of substituent on rings A and B, their electron donor/withdrawing, as well as their dimension/spatial properties. There is a preference for electron donating groups on ring A, such as Me in position 5, or better, 5, 6-diMe. Ring B must be of the pyridine type such as picolinamide, other modifications are generally not favorable. Two molecules, 1 and 33 displayed antiplasmodial activity in the high nanomolar range against the chloroquine sensitive strain, with selectivity indexes above 10. Activity results of 1, 12 and 16 on a chloroquine resistance strain indicated an activity close to chloroquine for compound 1. Analysis of some of their effect on the parasites seem to suggest that 1 and 33 affect only the parasite and use a route other than interference with hemozoin biocrystallization, the route used by chloroquine and most antimalarials.

Exploring ibuprofen derivatives as α-glucosidase and lipoxygenase inhibitors: Cytotoxicity and in silico studies

This study reports the synthesis of a series of ibuprofen derivatives, including thiosemicarbazides 4a-f, 1,3,4-oxadiazoles 5a-f, 1,3,4-thiadiazoles 6a-f, 1,2,4-triazoles 7a-f, and their S-alkylated derivatives 8a-d. All of the newly synthesized derivatives were analyzed using ¹ H NMR, ¹³ C NMR spectroscopy, and high-resolution mass spectra (electron ionization) spectrometry. These synthetic molecules were examined for their in vitro baking yeast α-glucosidase and soybean 15-lipoxygenase (15-LOX) inhibition and cell viability studies. The results revealed that the compounds N-(3,4-dichlorophenyl)-5-[1-(4-isobutylphenyl)ethyl]-1,3,4-oxadiazol-2-amine 5f (IC₅₀ 3.05 ± 1.23 µM) and N-(3-fluorophenyl)-5-[1-(4-isobutylphenyl)ethyl]-1,3,4-oxadiazol-2-amine 5b (IC₅₀ 3.12 ± 1.21 µM) were the most potent with respect to the α-glucosidase enzyme while in case of 15-LOX, the compound 4-(2,4-dichlorophenyl)-1-[2-(4-isobutylphenyl)propanoyl]thiosemicarbazide 4e showed potent inhibition with an IC₅₀ value of 55.41 ± 0.41 µM. All these compounds were found least toxic by displaying a blood mononuclear cell viability value of 69.2%-97.8% by the MTT assay compared to the standards when assayed at 0.25 mM concentration. Molecular docking analyses were conducted to evaluate the inhibition profiles of these derivatives against the said enzymes and the data supported the in vitro profiles.

Synthesis of Benzimidazole-Sulfonyl Derivatives and Their Biological Activities

Currently, the synthesis of new compounds with potential bioactivities has become a central issue in the drug discovery arena. Among these new compounds, benzimidazole-sulfonyl scaffolds have vital applications in the fields of pharmaceuticals industries. Benzimidazole and sulfonyl compounds have remarkable biological activities, such as antibacterial, antifungal, anti-inflammatory, antiproliferative, carbonic anhydrase inhibitory, and α-amylase inhibitory activities. Furthermore, recent literature mentions the synthesis and bioactivities of some benzimidazole-sulfonyl hybrids. In this review, we focus on reviewing the synthesis of these hybrid scaffolds and their various types of biological activities of the compounds.

Development of An HPLC Method for the Determination of Mesalazine in Human Plasma by Fluorimetric Derivatization and Application to A Prototype Pharmacokinetic Study

In this study, a new, fast and sensitive HPLC method with fluorometric detection was developed for the determination of mesalazine in human plasma and applied to a pharmacokinetic study. Mesalazine was precolumn derivatized with NBD-Cl and the fluorescent derivative was separated on a C18 (150 × 4.6 mm × 2.6 μm) analytical column at 30 ºC using a mobile phase composed of acetonitrile-0.1% o-phosphoric acid in water (70:30, v/v) by isocratic elution with flow rate of 1.0 mL min^-1. The method was based on the measurement of the derivative using fluorescence detection (λ_ex = 280 nm, λ_em = 325 nm). The retention time of mesalazine is 3.08 ± 0.06 min. Nortriptiline was used as internal standard. This currently developed method was validated according to ICH criteria by evaluating the specificity, linearity, precision, accuracy and robustness. The method was determined to be linear in a concentration range of 0.25-1.5 μg mL^-1 with the correlation coefficient of 0.9997. LOD and LOQ were found to be 0.075 and 0.25 μg mL^-1, respectively. Intraday and interday RSD values were less than 5.92%. The plasma concentration-time profile and pharmacokinetic parameters such as AUC_0-t, AUC_0-∞, C_max, t_max, t_1/2, were calculated according to the assays. The presented method can certainly be used for bioequivalence and bioavailability investigations and routine analysis of the drug in plasma.

Synthesis of Antimicrobial Benzimidazole-Pyrazole Compounds and Their Biological Activities

The synthesis of new compounds with antimicrobial and antiviral properties is a central objective today in the context of the COVID-19 pandemic. Benzimidazole and pyrazole compounds have remarkable biological properties, such as antimicrobial, antiviral, antitumor, analgesic, anti-inflammatory, anti-Alzheimer's, antiulcer, antidiabetic. Moreover, recent literature mentions the syntheses and antimicrobial properties of some benzimidazole-pyrazole hybrids, as well as other biological properties thereof. In this review, we aim to review the methods of synthesis of these hybrids, the antimicrobial activities of the compounds, their correlation with various groups present on the molecule, as well as their pharmaceutical properties.

Synthesis, density functional theory study and in vitro antimicrobial evaluation of new benzimidazole Mannich bases

The tri-component synthesis of novel chiral benzimidazole Mannich bases, by reaction between benzimidazole, aqueous 30% formaldehyde and an amine, the biological evaluation and DFT studies of the new compounds are reported here. The ¹H-NMR, ¹³C-NMR, FTIR spectra and elemental analysis confirm the structures of the new compounds. All synthesized compounds were screened by qualitative and quantitative methods for their in vitro antibacterial activity against 4 bacterial strains. DFT studies were accomplished using GAMESS 2012 software and HOMO-LUMO analysis allowed the calculation of electronic and structural parameters of the chiral Mannich bases. The geometry of 1-methylpiperazine, the cumulated Mullikan atomic charges of the two heteroatoms and of the methyl, and the value of the global electrophilicity index (ω = 0.0527) of the M-1 molecule is correlated with its good antimicrobial activity. It was found that the presence of saturated heterocycles from the amine molecule, 1-methyl piperazine and morpholine, respectively, contributes to an increased biological activity, compared to aromatic amino analogs, diphenylamino-, 4-nitroamino- and 4-aminobenzoic acid. The planarity of the molecules, specific bond lengths and localization of HOMO-LUMO orbitals is responsible for the best biological activities of the compounds.

Synthesis, biological evaluation and model membrane studies on metal complexes containing aromatic N,O-chelate ligands

Novel lanthanide (Ln) compounds [Ln(L)₂]Cl^.xH₂O (Ln = La³⁺, Ce³⁺, Sm³⁺) containing aromatic N,O-chelate ligands [HL1 = 4-amino-2-(1H-benzimidazol-2-yl)phenol; HL2 = 5-amino-2-(1H-benzimidazol-2-yl)phenol] have been synthesized and structurally characterized by elemental analysis, NMR and IR spectroscopy, molar conductance measurements, and mass spectrometry (MS). The spectroscopic data suggested that the benzimidazolyl-phenol ligands act as N,O-chelate ligands through the iminic nitrogen and phenolic oxygen atoms. Elemental analysis indicated that lanthanide compounds were formed in a 1:2 stoichiometry (metal:ligand). In vitro biological evaluation was carried out using these complexes, exhibiting moderate cytotoxicity against six different human tumor cell lines (U251, human glioblastoma; HCT-15, colorectal carcinoma; MCF-7, breast epithelial adenocarcinoma; PC-3, prostate cancer; K562, myelogenous leukemia; SKLU-1, lung carcinoma) and lower toxicity against a non-cancerous cell line (COS-7, primate kidney). In addition, the antibacterial activity of the compounds was assessed against two gram-positive strains (Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19115) and two gram-negative strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27583) using the microdilution method. The results obtained show that the metal complexes exhibit higher biological activity than the free ligands, confirming a synergistic effect. Further benzimidazolyl-phenol derivatives were explored for the detection of bacteria using fluorescence imaging studies. Interestingly, the fluorescent properties of these compounds make them potential candidates to monitor the morphology of bacteria at different compound concentrations. Hence, the interaction of the ligand and complexes with model membranes mimicking those of bacteria was studied by using differential scanning calorimetry (DSC) and molecular dynamics (MD), showing that both compounds decreased the enthalpy of transition in two model membranes as the concentration of the compounds increased. In addition, the main transition temperature was slightly reduced as a result of these interactions.

Benzimidazole Containing Acetamide Derivatives Attenuate Neuroinflammation and Oxidative Stress in Ethanol-Induced Neurodegeneration

Oxidative stress-induced neuroinflammation is the prominent feature of neurodegenerative disorders, and is characterized by a gradual decline of structure and function of neurons. Many biochemical events emerge thanks to the result of this neurodegeneration, and ultimately provoke neuroinflammation, activation of microglia, and oxidative stress, leading to neuronal death. This cascade not only explains the complexity of events taking place across different stages, but also depicts the need for more effective therapeutic agents. The present study was designed to investigate the neuroprotective effects of newly synthesized benzimidazole containing acetamide derivatives, 3a (2-(4-methoxyanilino)-N-[1-(4-methylbenzene-1-sulfonyl)-1H-benzimidazol-2-yl] acetamide) and 3b (2-(Dodecylamino)-N-[1-(4-methylbenzene-1-sulfonyl)-1H-benzimidazol-2-yl] acetamide) against ethanol-induced neurodegeneration in the rat model. Both derivatives were characterized spectroscopically by proton NMR (¹H-NMR) and carbon-13 NMR (¹³C-NMR) and evaluated for neuroprotective potential using different pharmacological approaches. In vivo experiments demonstrated that ethanol triggered neurodegeneration characterized by impaired antioxidant enzymes and elevated oxidative stress. Furthermore, ethanol administration induced neuroinflammation, as demonstrated by elevated expression of tumor necrotic factor (TNF-α), nuclear factor κB (NF-κB), cyclooxygenase-2 (COX2), and ionized calcium-binding adapter molecule-1 (Iba-1), which was further validated by enzyme-linked immunosorbent assay (ELISA). Treatment with 3a and 3b ameliorated the ethanol-induced oxidative stress, neuroinflammation, and memory impairment. The affinity of synthesized derivatives towards various receptors involved in neurodegeneration was assessed through docking analysis. The versatile nature of benzimidazole nucleus and its affinity toward several receptors suggested that it could be a multistep targeting neuroprotectant. As repetitive clinical trials of neuroprotectants targeting a single step of the pathological process have failed previously, our results suggested that a neuroprotective strategy of acting at different stages may be more advantageous to intervene in the vicious cycles of neuroinflammation.

Antimicrobial Potential of Benzimidazole Derived Molecules

Structural resemblance of benzimidazole nucleus with purine nucleus in nucleotides makes benzimidazole derivatives attractive ligands to interact with biopolymers of a living system. The most prominent benzimidazole compound in nature is N-ribosyldimethylbenzimidazole, which serves as an axial ligand for cobalt in vitamin B12. This structural similarity prompted medicinal chemists across the globe to synthesize a variety of benzimidazole derivatives and to screen those for various biological activities, such as anticancer, hormone antagonist, antiviral, anti-HIV, anthelmintic, antiprotozoal, antimicrobial, antihypertensive, anti-inflammatory, analgesic, anxiolytic, antiallergic, coagulant, anticoagulant, antioxidant and antidiabetic activities. Hence, benzimidazole nucleus is considered as a privileged structure in drug discovery, and it is exploited by many research groups to develop numerous compounds that are purported to be antimicrobial. Despite a large volume of research in this area, no novel benzimidazole derived compound has emerged as clinically effective antimicrobial drug. In the present review, we have compiled various reports on benzimidazole derived antimicrobials, classified as monosubstituted, disubstituted, trisubstituted and tetrasubstituted benzimidazoles, bisbenzimidazoles, fused-benzimidazoles, and benzimidazole derivative-metal complexes. The purpose is to collate these research reports, and to generate a generalised outlay of benzimidazole derived molecules that can assist the medicinal chemists in selecting appropriate combination of substituents around the nucleus for designing potent antimicrobials.

Carbene-catalyzed enantioselective oxidative coupling of enals and di(hetero)arylmethanes

Di(hetero)arylmethane is a unique structural motif for natural and synthetic functional molecules. To date, it remains challenging to functionalize the diaryl methyl sp3 carbon-hydrogen bond directly in an enantioselective manner. This is likely due to the relatively inert nature of the carbon-hydrogen bond and the difficult enantiofacial discrimination of two sterically similar aryl substituents. Here we disclose an N-heterocyclic carbene-catalyzed direct oxidative coupling of enals and di(hetero)arylmethanes. Our method allows for highly enantioselective transformation of diaryl methanes and quick access to benzimidazole fused lactams.

New mesalamine polymeric conjugate for controlled release: Preparation, characterization and biodistribution study

Mesalamine (5-ASA) consists of the first-line therapy for the treatment of ulcerative colitis; however, it has low bioavailability, can cause several systemic adverse events, and has low treatment adherence due to the inconvenient dosing scheme. In this work, a new drug delivery system consisting of chondroitin sulfate linked to 5-ASA was synthesized using a carbodiimide as conjugating agent. The system was characterized by spectroscopic techniques (UV, ATR-FTIR, XRD, and NMR ¹H) and thermal analysis (TG/DTG and DSC), suggesting the conjugation between the drug and the polymer. The in vitro release and the corresponding kinetics were also evaluated, revealing that approximately 40% of the drug linked was released at pH9 for up to 50h, following Higuchi's model. The conjugate did not show cytotoxicity for the human monocytic cell line at the doses tested, and an in vivo biodistribution study showed that the conjugate remained in the lower GIT for up to 8h with no uptake in the upper GIT. These data corroborate with the radiation found per segment of GIT and in blood. For this last test the conjugate was radiolabeled with Technetium-99m to allow the scintigraphy evaluation and radiation quantification. In conclusion, the polymeric conjugate was successfully synthesized and demonstrated a mucoadhesiveness on the colon as desired, thus supporting its potential use in the treatment of ulcerative colitis.

Therapeutic evolution of benzimidazole derivatives in the last quinquennial period

Benzimidazole, a fused heterocycle bearing benzene and imidazole has gained considerable attention in the field of contemporary medicinal chemistry. The moiety is of substantial importance because of its wide array of pharmacological activities. This nitrogen containing heterocycle is a part of a number of therapeutically used agents. Moreover, a number of patents concerning this moiety in the last few years further highlight its worth. The present review covers the recent work published by scientists across the globe during last five years.

Synthesis, anti-inflammatory, bactericidal activities and docking studies of novel 1,2,3-triazoles derived from ibuprofen using click chemistry

BACKGROUND

Nonsteroidal anti-inflammatory drugs are of vast therapeutic benefit in the treatment of different types of inflammatory conditions. 1,2,3-Triazoles and their derivatives have a wide range of applications as anti-bacterial, anti-fungal, anti-tubercular, cytostatic, anti-HIV, anti-allergic, anti-neoplastic and anti-inflammatory (AI) agents. Considering the individual biological and medicinal importance of ibuprofen and 1,2,3-triazoles, we wanted to explore novel chemical entities based on ibuprofen and triazole moieties towards their biological significance.

RESULTS

Click chemistry has utilized as an ideal strategy to prepare novel ibuprofen-based 1,4-disubstituted 1,2,3-triazole containing molecules. These compounds were screened for their in vivo AI activity, among all the synthesized analogues 13o was shown potent effect than the reference AI drug ibuprofen at the same concentration (10 mg/kg body weight). Compounds 13l, 13g, 13c, 13k, 13i, 13n, 13m and 13j were shown significant AI activity. These triazole analogues were also screened for their bactericidal profile. Compounds 13c, 13i, 13l and 13o exhibited considerable bactericidal activity against gram positive and gram negative strains. In addition to this, molecular docking studies were also carried out into cyclooxygenase-2 active site to predict the affinity and orientation of these novel compounds (13a-q).

CONCLUSIONS

In summary, we have designed and synthesized 1,2,3-triazole analogues of ibuprofen in good yields using Click chemistry approach. AI and bactericidal activities of these compounds were evaluated and shown remarkable results.