Novel coumarin-benzimidazole derivatives as antioxidants and safer anti-inflammatory agents

Sugar functionalized coumarin motifs: Synthesis and applications

Sugars are vital biomolecules widely found in nature, playing an indispensable role in a plethora of biological processes. Similarly, coumarins are heterocycles with an effective pharmacophore skeleton, making them crucial in drug design and development. Coupling carbohydrate moieties to the small biologically active molecules creates a vast library of glycoconjugates with impressive structural diversity. The potential of coumarin glycosides is being extensively explored due to their broad spectrum of applications, including antibacterial, anticancer, and anticoagulant properties, etc. This review highlights various chemical methodologies for synthesizing diverse coumarin glycohybrids with distinct linkages and explores their immense biological potential, making a significant contribution to the field of organic synthesis.

Coumarin: A natural solution for alleviating inflammatory disorders

Coumarin, a naturally occurring compound found in various plants, has a rich history of use in traditional medicine. Recent research has highlighted its anti-inflammatory properties, positioning it as a promising candidate for treating inflammatory disorders such as rheumatoid arthritis, asthma, and inflammatory bowel disease. This narrative review aims to comprehensively summarize the current knowledge regarding coumarin's pharmacological effects in alleviating inflammatory conditions by analyzing preclinical and clinical studies. The review focuses on elucidating the mechanisms through which coumarin exerts its anti-inflammatory effects, including its antioxidant activity, inhibiting pro-inflammatory cytokine production, and modulation of immune cell functions. Additionally, the paper addresses potential limitations of using coumarin, such as concerns about toxicity at high doses or with prolonged use. Before widespread clinical application, further investigation is needed to fully understand coumarin's potential benefits and risks.

Coumarin/β-Cyclodextrin Inclusion Complexes Promote Acceleration and Improvement of Wound Healing

Coumarins have great pharmacotherapeutic potential, presenting several biological and pharmaceutical applications, like antibiotic, fungicidal, anti-inflammatory, anticancer, anti-HIV, and healing activities, among others. These molecules are practically insoluble in water, and for biological applications, it became necessary to complex them with cyclodextrins (CDs), which influence their bioavailability in the target organism. In this work, we studied two coumarins, and it was possible to conclude that there were structural differences between 4,7-dimethyl-2H-chromen-2-one (DMC) and 7-methoxy-4-methyl-2H-chromen-2-one (MMC)/β-CD that were solubilized in ethanol, frozen, and lyophilized (FL) and the mechanical mixtures (MM). In addition, the inclusion complex formation improved the solubility of DMC and MMC in an aqueous medium. According to the data, the inclusion complexes were formed and are more stable at a molar ratio of 2:1 coumarin/β-CD, and hydrogen bonds along with π-π stacking interactions are responsible for the better stability, especially for (MMC)2@β-CD. In vivo wound healing studies in mice showed faster re-epithelialization and the best deposition of collagen with the (DMC)2@β-CD (FL) and (MMC)2@β-CD (FL) inclusion complexes, demonstrating clearly that they have potential in wound repair. Therefore, (DMC)2@β-CD (FL) deserves great attention because it presented excellent results, reducing the granulation tissue and mast cell density and improving collagen remodeling. Finally, the protein binding studies suggested that the anti-inflammatory activities might exert their biological function through the inhibition of MEK, providing the possibility of development of new MEK inhibitors.

From lab to nature: Recent advancements in the journey of gastroprotective agents from medicinal chemistry to phytotherapy

Peptic ulcer, affecting 10 % of the global population, results from imbalances in gastric juice pH and diminished mucosal defences. Key underlying factors are non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori infection, undermining mucosal resistance. Traditional treatments like proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists exhibit drawbacks such as adverse effects, relapses, and drug interactions. This review extensively explores the ethnomedicinal, synthetic and pharmacological facets of various potential peptic ulcer treatments. Rigorous methodologies involving electronic databases, and chemical structure verification via 'PubChem' and 'SciFinder' enhance the review's credibility. The provided information, spanning medicinal insights to intricate pharmacological mechanisms, establishes a robust groundwork for future research and the development of plant-derived or synthetic molecules for peptic ulcers, offering a promising alternative to conventional therapies.

Therapeutic Potential of Benzimidazoisoquinoline Derivatives in Alleviating Murine Hepatic Fibrosis

Short Title: Benzimidazoisoquinoline derivatives as potent antifibrotics Hepatic fibrosis is a pathological condition of liver disease with an increasing number of cases worldwide. Therapeutic strategies are warranted to target the activated hepatic stellate cells (HSCs), the collagen-producing cells, an effective strategy for controlling the disease progression. Benzimidazoisoquinoline derivatives were synthesized as hybrid molecules by the combination of benzimidazoles and isoquinolines to evaluate their anti-fibrotic potential using an in-vitro and in-vivo model of hepatic fibrosis. A small library of benzimidazoisoquinoline derivatives (1-17 and 18-21) was synthesized from 2-aryl benzimidazole and acetylene functionalities through C-H and N-H activation. Compounds (10 and its recently synthesized derivatives 18-21) depicted a significant decrease in PDGF-BB and/or TGFβ-induced proliferation (1.7-1.9 -fold), migration (3.5-5.0 -fold), and fibrosis-related gene expressions in HSCs. These compounds could revert the hepatic damage caused by chronic exposure to hepatotoxicants, ethanol, and/or carbon tetrachloride as evident from the histological, biochemical, and molecular analysis. Anti-fibrotic effect of the compounds was supported by the decrease in the malondialdehyde level, collagen deposition, and gene expression levels of fibrosis-related markers such as α-SMA, COL1α1, PDGFRβ, and TGFRIIβ in the preclinical models of hepatic fibrosis. In conclusion, the synthesized benzimidazoisoquinoline derivatives (compounds 18, 19, 20, and 21) possess anti-fibrotic therapeutic potential against liver fibrosis.

A Critical Review on Therapeutic Potential of Benzimidazole Derivatives: A Privileged Scaffold

Benzimidazole nucleus is a predominant heterocycle displaying a wide spectrum of pharmacological activities. The privileged nature of the benzimidazole scaffold has been revealed by its presence in most small molecule drugs and in its ability to bind multiple receptors with high affinity. A literature review of the scaffold reveals several instances where structural modifications of the benzimidazole core have resulted in high-affinity lead compounds against a variety of biological targets. Hence, this structural moiety offers opportunities to discover novel, better, safe and highly potent biological agents. The goal of the present review is to compile the medicinal properties of benzimidazole derivatives with a focus on SAR (Structure-Activity Relationships).

Recent achievements in the synthesis of benzimidazole derivatives

Benzimidazoles are a class of heterocyclic compounds in which a benzene ring is fused to the 4 and 5 positions of an imidazole ring. Benzimidazole refers to the parent compound, while benzimidazoles are a class of heterocyclic compounds having similar ring structures, but different substituents. Benzimidazole derivatives possess a wide range of bioactivities including antimicrobial, anthelmintic, antiviral, anticancer, and antihypertensive activities. Many compounds possessing a benzimidazole skeleton have been employed as drugs in the market. The application of benzimidazoles in other fields has also been documented. The synthesis of benzimidazole derivatives has attracted much attention from chemists and numerous articles on the synthesis of this class of heterocyclic compound have been reported over the years. The condensation between 1,2-benzenediamine and aldehydes has received intensive interest, while many novel methods have been developed. In this article, we will give a comprehensive review of studies on the synthesis of benzimidazole, which date back to 2013. We have also tried to describe reaction mechanisms as much as we can. The work might be useful for chemists who work in the synthesis of heterocycles or drug chemistry.

Biological evaluation of novel amidino substituted coumarin-benzazole hybrids as promising therapeutic agents

Herein we present the design and the synthesis of novel substituted coumarin-benzimidazole/benzothiazole hybrids bearing a cyclic amidino group on the benzazole core as biologically active agents. All prepared compounds were evaluated for their in vitro antiviral and antioxidative activity as well as for their in vitro antiproliferative activity against a panel of several human cancer cell lines. Coumarin-benzimidazole hybrid 10 (EC50 9.0-43.8 μM) displayed the most promising broad spectrum antiviral activity, while two other coumarin-benzimidazole hybrids 13 and 14 showed the highest antioxidative capacity in the ABTS assay, superior to the reference standard BHT (IC50 0.17 and 0.11 mM, respectively). Computational analysis supported these results and demonstrated that these hybrids benefit from the high C-H hydrogen atom releasing tendency of the cationic amidine unit, and the pronounced ease with which they can liberate an electron, promoted by the electron-donating diethylamine group on the coumarin core. The coumarin ring substitution at position 7 with a N,N-diethylamino group also caused a significant enhancement of the antiproliferative activity, with the most active compounds being derivatives with a 2-imidazolinyl amidine group 13 (IC50 0.3-1.9 μM) and benzothiazole derivative with a hexacyclic amidine group 18 (IC50 1.3-2.0 μM).

Therapeutic Effects of Coumarins with Different Substitution Patterns

The use of derivatives of natural and synthetic origin has gained attention because of their therapeutic effects against human diseases. Coumarins are one of the most common organic molecules and are used in medicine for their pharmacological and biological effects, such as anti-inflammatory, anticoagulant, antihypertensive, anticonvulsant, antioxidant, antimicrobial, and neuroprotective, among others. In addition, coumarin derivates can modulate signaling pathways that impact several cell processes. The objective of this review is to provide a narrative overview of the use of coumarin-derived compounds as potential therapeutic agents, as it has been shown that substituents on the basic core of coumarin have therapeutic effects against several human diseases and types of cancer, including breast, lung, colorectal, liver, and kidney cancer. In published studies, molecular docking has represented a powerful tool to evaluate and explain how these compounds selectively bind to proteins involved in various cellular processes, leading to specific interactions with a beneficial impact on human health. We also included studies that evaluated molecular interactions to identify potential biological targets with beneficial effects against human diseases.

Benzimidazole and its derivatives as cancer therapeutics: The potential role from traditional to precision medicine

Cancer is the second leading cause of mortality globally which remains a continuing threat to human health today. Drug insensitivity and resistance are critical hurdles in cancer treatment; therefore, the development of new entities targeting malignant cells is considered a high priority. Targeted therapy is the cornerstone of precision medicine. The synthesis of benzimidazole has garnered the attention of medicinal chemists and biologists due to its remarkable medicinal and pharmacological properties. Benzimidazole has a heterocyclic pharmacophore, which is an essential scaffold in drug and pharmaceutical development. Multiple studies have demonstrated the bioactivities of benzimidazole and its derivatives as potential anticancer therapeutics, either through targeting specific molecules or non-gene-specific strategies. This review provides an update on the mechanism of actions of various benzimidazole derivatives and the structure‒activity relationship from conventional anticancer to precision healthcare and from bench to clinics.

N-substitution Reactions of 2-Aminobenzimidazoles to Access Pharmacophores

Benzimidazole (BI) and its derivatives are interesting molecules in medicinal chemistry because several of these compounds have a diversity of biological activities and some of them are even used in clinical applications. In view of the importance of these compounds, synthetic chemists are still interested in finding new procedures for the synthesis of these classes of compounds. Astemizole (antihistaminic), Omeprazole (antiulcerative), and Rabendazole (fungicide) are important examples of compounds used in medicinal chemistry containing BI nuclei. It is interesting to observe that several of these compounds contain 2-aminobenzimidazole (2ABI) as the base nucleus. The structures of 2ABI derivatives are interesting because they have a planar delocalized structure with a cyclic guanidine group, which have three nitrogen atoms with free lone pairs and labile hydrogen atoms. The 10-π electron system of the aromatic BI ring conjugated with the nitrogen lone pair of the hexocyclic amino group, making these heterocycles to have an amphoteric character. Synthetic chemists have used 2ABI as a building block to produce BI derivatives as medicinally important molecules. In view of the importance of the BIs, and because no review was found in the literature about this topic, we reviewed and summarized the procedures related to the recent methodologies used in the N-substitution reactions of 2ABIs by using aliphatic and aromatic halogenides, dihalogenides, acid chlorides, alkylsulfonic chlorides, carboxylic acids, esters, ethyl chloroformates, anhydrides, SMe-isothioureas, alcohols, alkyl cyanates, thiocyanates, carbon disulfide and aldehydes or ketones to form Schiff bases. The use of diazotized 2ABI as intermediate to obtain 2-diazoBIs was included to produce Nsubstituted 2ABIs of pharmacological interest. Some commentaries about their biological activity were included.

Synthesis and Biological Properties of Coumarin Analogue: A Brief Review

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One of the most prominent aromatic organic chemical compound is Coumarin having formula C9H6O2 which is widely known for its benefits in drug industry. Colourless crystalline solid having sweet scent is coumarin’s physical identity. It serves various purposes such as in synthesis of medicines, laser dyes, perfumes and many more. Having enormous usages it becomes important to synthesize such compound so various reactions were performed in order to obtain coumarins. This review explicates the preparation of coumarin by Pechmann Condensation and its biological characteristics.

Coumarins Synthesis and Transformation via C–H Bond Activation—A Review

For several decades, coumarins have attracted considerable attention due to the fact of their application in diverse fields such as medical science and biomedical research as well as several industrial branches. Recently, many compounds containing the coumarin moiety have been intensively studied, mainly due to the fact of their biological activities such as antitumor, antioxidative, anti-HIV, vasorelaxant, antimicrobial, and anticancer. They are also widely used as fluorescent dyes and probes because of their great structural flexibility and large fluorescent quantum yields. For this reason, numerous attempts have been made to develop new and more practical methods for the synthesis of these compounds. This review aims at providing a comprehensive overview of coumarin synthesis methods by direct C–H bond activation in order to demonstrate the current state-of-the-art methods as well as the current limitations.

Coumarin-benzimidazole hybrids: A review of developments in medicinal chemistry

Coumarin and benzimidazole are privileged structures in medicinal chemistry and are widely used in drug discovery and development due to their vast biological properties. The pharmacokinetic and pharmacodynamic properties of the individual scaffolds can be improved by developing coumarin-benzimidazole chimeric molecules via molecular hybridization approach. The three major classes of coumarin-benzimidazole hybrids are merged, fused and spacer-linked hybrids. Depending on the substitution position, fused hybrids and spacer-linked hybrids can be further classified as coumarin-C3 hybrids, coumarin-C4 hybrids and coumarin-C5/6/7/8 hybrids. Most of the coumarin-benzimidazole hybrid molecules exhibited potent anticancer, antiviral, antimicrobial, antitubercular, anthelmintic, anti-inflammatory, antioxidant, anticonvulsant and carbonic anhydrase inhibitory activities. The fused coumarin-C3 hybrid (2), thiomethylene-linked coumarin-C3 hybrid (45), N-glucoside substituted thiomethylene-linked coumarin-C3 hybrid (37c), amide-linked coumarin-C3 hybrid (50a), and sulfonylmethylene-linked coumarin-C4 hybrid (63) were identified as the representative potent anticancer, antimicrobial, antiviral, antioxidant and antitubercular agents respectively. The biological properties of the different classes of coumarin-benzimidazole hybrids with their structure-activity relationship studies and the mechanism of action studies were presented in this review, aiming to help the researchers across the globe to generate future hybrid molecules as potential drug candidates.

Visible light photocatalysis in the synthesis of pharmaceutically relevant heterocyclic scaffolds

Visible light and photoredox catalysis have emerged as a powerful and long-lasting tool for organic synthesis, demonstrating the importance of a variety of chemical bond formation methods.

A Comprehensive Account on Recent Progress in Pharmacological Activities of Benzimidazole Derivatives

Nowadays, nitrogenous heterocyclic molecules have attracted a great deal of interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole scaffolds are considerably prevalent. Due to their isostructural pharmacophore of naturally occurring active biomolecules, benzimidazole derivatives have significant importance as chemotherapeutic agents in diverse clinical conditions. Researchers have synthesized plenty of benzimidazole derivatives in the last decades, amidst a large share of these compounds exerted excellent bioactivity against many ailments with outstanding bioavailability, safety, and stability profiles. In this comprehensive review, we have summarized the bioactivity of the benzimidazole derivatives reported in recent literature (2012-2021) with their available structure-activity relationship. Compounds bearing benzimidazole nucleus possess broad-spectrum pharmacological properties ranging from common antibacterial effects to the world's most virulent diseases. Several promising therapeutic candidates are undergoing human trials, and some of these are going to be approved for clinical use. However, notable challenges, such as drug resistance, costly and tedious synthetic methods, little structural information of receptors, lack of advanced software, and so on, are still viable to be overcome for further research.

Evaluation of the Inhibitory Effects of Pyridylpyrazole Derivatives on LPS-Induced PGE2 Productions and Nitric Oxide in Murine RAW 264.7 Macrophages

A series of thirteen triarylpyrazole analogs were investigated as inhibitors of lipopolysaccharide (LPS)-induced prostaglandin E₂ (PGE₂) and nitric oxide (NO) production in RAW 264.7 macrophages. The target compounds 1a-m have first been assessed for cytotoxicity against RAW 264.7 macrophages to determine their non-cytotoxic concentration(s) for anti-inflammatory testing to make sure that the inhibition of PGE₂ and NO production would not be caused by cytotoxicity. It was found that compounds 1f and 1m were the most potent PGE₂ inhibitors with IC₅₀ values of 7.1 and 1.1 μM, respectively. In addition, these compounds also showed inhibitory effects of 11.6% and 37.19% on LPS-induced NO production, respectively. The western blots analysis of COX-2 and iNOS showed that the PGE₂ and NO inhibitory effect of compound 1m are attributed to inhibition of COX-2 and iNOS protein expression through inactivation of p38.

Structure-Activity Relationship Analysis of Benzimidazoles as Emerging Anti-Inflammatory Agents: An Overview

A significant number of the anti-inflammatory drugs currently in use are becoming obsolete. These are exceptionally hazardous for long-term use because of their possible unfavourable impacts. Subsequently, in the ebb-and-flow decade, analysts and researchers are engaged in developing new anti-inflammatory drugs, and many such agents are in the later phases of clinical trials. Molecules with heterocyclic nuclei are similar to various natural antecedents, thus acquiring immense consideration from scientific experts and researchers. The arguably most adaptable heterocyclic cores are benzimidazoles containing nitrogen in a bicyclic scaffold. Numerous benzimidazole drugs are broadly used in the treatment of numerous diseases, showing promising therapeutic potential. Benzimidazole derivatives exert anti-inflammatory effects mainly by interacting with transient receptor potential vanilloid-1, cannabinoid receptors, bradykinin receptors, specific cytokines, 5-lipoxygenase activating protein and cyclooxygenase. Literature on structure–activity relationship (SAR) and investigations of benzimidazoles highlight that the substituent’s tendency and position on the benzimidazole ring significantly contribute to the anti-inflammatory activity. Reported SAR analyses indicate that substitution at the N1, C2, C5 and C6 positions of the benzimidazole scaffold greatly influence the anti-inflammatory activity. For example, benzimidazole substituted with anacardic acid on C2 inhibits COX-2, and 5-carboxamide or sulfamoyl or sulfonyl benzimidazole antagonises the cannabinoid receptor, whereas the C2 diarylamine and C3 carboxamide substitution of the benzimidazole scaffold result in antagonism of the bradykinin receptor. In this review, we examine the insights regarding the SARs of anti-inflammatory benzimidazole compounds, which will be helpful for researchers in designing and developing potential anti-inflammatory drugs to target inflammation-promoting enzymes.

Green synthesis of therapeutically active 1,3,4-oxadiazoles as antioxidants, selective COX-2 inhibitors and their in silico studies

A modest, competent and green synthetic procedure for novel coumarinyl-1,3,4-oxadiazolyl-2-mercaptobenzoxazoles 8i-t has been reported. Analysis of the docked (PDB ID: 5IKR; A-Chain) poses of the compounds illustrated that they adopt identical conformations to the extremely selective COX-2 inhibitor. The biological outcomes as well as computational study suggested that the compounds originated to have elevated resemblance towards COX-2 enzyme than COX-1. The compounds 8i, 8l, 8q, 8r, 8s and 8t emerged as most potent and selective COX-2 inhibitors in contrast with Mefenamic acid. The selectivity index of 8l, 8n and 8r was respectively found to be 33.95, 20.25 and 24.98 which manifested their high selectivity against COX-2. Interestingly, the compounds which were active as COX-2 inhibitors were also active as antioxidant agents.

Synthesis and anti-rheumatoid arthritis activities of 3-(4-aminophenyl)-coumarin derivatives

Rheumatoid arthritis is a chronic systemic disease characterised by an unknown aetiology of inflammatory synovitis. A large number of studies have shown that synoviocytes show tumour-like dysplasia in the pathological process of RA, and the changes in the expression of related cytokines are closely related to the pathogenesis of RA. In this thesis, a series of novel 3-(4-aminophenyl) coumarins containing different substituents were synthesised to find new coumarin anti-inflammatory drugs for the treatment of rheumatoid arthritis. The results of preliminary activity screening showed that compound 5e had the strongest inhibitory activity on the proliferation of fibroid synovial cells, and it also had inhibitory effect on RA-related cytokines IL-1, IL-6, and TNF-α. The preliminary mechanism study showed that compound 5e could inhibit the activation of NF-κB and MAPKs signal pathway. The anti-inflammatory activity of compound 5ein vivo was further determined in the rat joint inflammation model.

Recent advancements on Benzimidazole: A versatile scaffold in medicinal chemistry

Benzimidazole is nitrogen containing fused heterocycle which has been extensively explored in medicinal chemistry. Benzimidizole nucleus has been found to possess various biological activities such as anticancer, antimicrobial, anti-inflammatory, antiviral, antitubercular and antidiabetic. A number of benzimidazoles such as bendamustine, pantoprazole have been approved for the treatment of various illnesses whereas galeterone and GSK461364 are in clinical trials. The present review article gives an overview about the different biological activities exhibited by the benzimidazole derivatives as well as different methods used for the synthesis of benzimidazole derivatives for the past ten years.

Benzimidazole based hybrids against complex diseases: A catalogue of the SAR profile

The fused heterocyclic ring system has been recognized as a privileged structure that is used as a template in medicinal chemistry for drug discovery. Benzimidazole is one of the common scaffolds found in several natural products such as histidine, purines, and an integral part of vitamin B12. This hetero-aromatic bicyclic ring system acts as a pharmacophore in various drugs of therapeutic interest and has a broad spectrum of activity. Literature reports suggest that diversely substituted benzimidazoles possess distinct pharmacological profiles with multi-targeting potential, thereby, an indispensable anchor for the development of novel therapeutic agents against complex diseases such as cancer, malaria, inflammatory disorders, microbial diseases, hypertension, etc. Thus, lots of efforts have been diverted towards exploring the therapeutic potential of benzimidazoles. Despite great efforts made by the research community, still, some multi-factorial diseases continue to progress due to their complex pathophysiology. Under these sets of circumstances, there is a need to explore this nucleus for hybrid designing with multi-targeting potential against complex diseases. Benzimidazole-based hybrids have been reported to treat multifactorial diseases, making it a scaffold of interest for various pharmaceutical companies and research groups. In this write-up, we shed light on the recent pharmacological profiles, various designing strategies, and structure-activity relationships (SAR) of different benzimidazole-based hybrids.

Design and synthesis of pyrimidine-5-carbonitrile hybrids as COX-2 inhibitors: Anti-inflammatory activity, ulcerogenic liability, histopathological and docking studies

Two new series of 1,3,4-oxadiazole and coumarin derivatives based on pyrimidine-5-carbonitrile scaffold have been synthesized and evaluated for their COX-1/COX-2 inhibitory activity. Compounds 10c, 10e, 10h-j, 14e-f, 14i and 16 were found to be the most potent and selective inhibitors of COX-2 (IC₅₀ 0.041-0.081 μM, SI 139.74-321.95). Eight compounds were further investigated for their in vivo anti-inflammatory activity. The most active derivatives 10c, 10j and 14e displayed superior in vivo anti-inflammatory activity (% edema inhibition 39.3-48.3, 1 h; 58.4-60.5, 2 h; 70.8-83.2, 3 h; 78.9-89.5, 4 h) to the reference drug celecoxib (% edema inhibition 38.0, 1 h; 48.8, 2 h; 58.4, 3 h; 65.4, 4 h). These derivatives were also tested for their ulcerogenic liability, compound 10j showed better safety profile with reference to celecoxib while 10c and 14e exhibited mild lesions. Molecular docking studies of 10c, 10j, and 14e in the COX-2 active site revealed similar orientation and binding interactions as selective COX-2 inhibitors with a higher liability to access the selectivity side pocket.

Promising Lead Compounds in the Development of Potential Clinical Drug Candidate for Drug-Resistant Tuberculosis

According to WHO report, globally about 10 million active tuberculosis cases, resulting in about 1.6 million deaths, further aggravated by drug-resistant tuberculosis and/or comorbidities with HIV and diabetes are present. Incomplete therapeutic regimen, meager dosing, and the capability of the latent and/or active state tubercular bacilli to abide and do survive against contemporary first-line and second line antitubercular drugs escalate the prevalence of drug-resistant tuberculosis. As a better understanding of tuberculosis, microanatomy has discovered an extended range of new promising antitubercular targets and diagnostic biomarkers. However, there are still no new approved antitubercular drugs of routine therapy for several decades, except for bedaquiline, delamanid, and pretomanid approved tentatively. Despite this, innovative methods are also urgently needed to find potential new antitubercular drug candidates, which potentially decimate both latent state and active state mycobacterium tuberculosis. To explore and identify the most potential antitubercular drug candidate among various reported compounds, we focused to highlight the promising lead derivatives of isoniazid, coumarin, griselimycin, and the antimicrobial peptides. The aim of the present review is to fascinate significant lead compounds in the development of potential clinical drug candidates that might be more precise and effective against drug-resistant tuberculosis, the world research looking for a long time.

Importance of Fluorine in Benzazole Compounds

Fluorine-containing heterocycles continue to receive considerable attention due to their unique properties. In medicinal chemistry, the incorporation of fluorine in small molecules imparts a significant enhancement their biological activities compared to non-fluorinated molecules. In this short review, we will highlight the importance of incorporating fluorine as a basic appendage in benzothiazole and benzimidazole skeletons. The chemistry and pharmacological activities of heterocycles containing fluorine during the past years are compiled and discussed.

Synthesis and Evaluation of New Coumarin Derivatives as Antioxidant, Antimicrobial, and Anti-Inflammatory Agents

New pyranocoumarin and coumarin-sulfonamide derivatives were prepared and evaluated for their antioxidant, antimicrobial, and/or anti-inflammatory activities. Coumarin-sulfonamide compounds 8a-d demonstrated significant antioxidant activity, while 7c,d, 8c,d, and 9c,d exhibited antimicrobial activity equal to or higher than the standard antimicrobials against at least one tested microorganism. Regarding the anti-inflammatory testing, pyranocoumarins 2b, 3a,b and 5c and coumarin-sulfonamide compound 9a showed more potent antiproteinase activity than aspirin in vitro; however, five compounds were as potent as aspirin. The anti-inflammatory activity of the promising compounds was further assessed pharmacologically on formaldehyde-induced rat paw oedema and showed significant inhibition of oedema. For in vitro COX-inhibitory activity of coumarin derivatives, pyranocoumarin derivative 5a was the most selective (SI = 152) and coumarin-sulfonamide derivative 8d was most active toward COX-2 isozyme. The most active derivatives met the in silico criteria for orally active drugs; thus, they may serve as promising candidates to develop more potent and highly efficient antioxidant, antimicrobial, and/or anti-inflammatory agents.

One-Pot Multicomponent Synthesis and Bioevaluation of Tetrahydroquinoline Derivatives as Potential Antioxidants, α-Amylase Enzyme Inhibitors, Anti-Cancerous and Anti-Inflammatory Agents

Mankind has always suffered from multiple diseases. Therefore, there has been a rigorous need in the field of medicinal chemistry for the design and discovery of new and potent molecular entities. In this work, thirteen tetrahydroquinoline derivatives were synthesized and evaluated biologically for their antioxidant, α-amylase enzyme inhibitory, anti-proliferative and anti-inflammatory activities. SF8 showed the lowest IC50 of 29.19 ± 0.25 µg/mL by scavenging DPPH free radicals. SF5 showed significant antioxidant activity in total antioxidant capacity (TAC) and total reducing power (TRP) assays. SF5 and SF9 showed the maximum inhibition of α-amylase enzyme i.e., 97.47% and 89.93%, respectively, at 200 µg/mL concentration. Five compounds were shortlisted to determine their anti-proliferative potential against Hep-2C cells. The study was conducted for 24, 48 and 72 h. SF8 showed significant results, having an IC50 value of 11.9 ± 1.04 µM at 72 h when compared with standard cisplatin (IC50 value of 14.6 ± 1.01 µM). An in vitro nitric oxide (NO) assay was performed to select compounds for in vivo anti-inflammatory activity evaluation. SF13 scavenged the NO level to a maximum of 85% at 50 µM concentration, followed by SF1 and SF2. Based on the NO scavenging assay results, in vivo anti-inflammatory studies were also performed and the results showed significant activity compared to the standard, acetylsalicylic acid (ASA).

Synthesis of 1-(β-coumarinyl)-1-(β-indolyl)trifluoroethanols through regioselective Friedel-Crafts alkylation of indoles with β-(trifluoroacetyl)coumarins catalyzed by Sc(OTf)3

A highly efficient Friedel-Crafts alkylation of indole derivatives with β-(trifluoroacetyl)coumarins using Sc(OTf)3 as a catalyst has been developed, which gives regioselective 1,2-adducts to afford 1-(β-coumarinyl)-1-(β-indolyl)trifluoroethanols. A series of tertiary trifluoroethanols containing different indole and coumarin groups were synthesized in moderate to excellent yields (up to 95%) in the presence of 5 mol% catalyst in a short time (only 2 minutes at least). A mechanism of the reaction, in which the trace amount of water plays the role of proton transfer in catalyzing circulation was proposed and confirmed.

Anti-inflammatory effect and inhibition of nitric oxide production by targeting COXs and iNOS enzymes with the 1,2-diphenylbenzimidazole pharmacophore

Being the base of several non-communicable diseases, including cancer, inflammation is a complex process generated by tissue damage or change in the body homeostatic state. Currently, the therapeutic treatment for chronic inflammation related diseases is based on the use of selective cyclooxygenase II enzyme, COX-2, inhibitors or Coxibs, which have recently regained attention giving their preventive role in colon cancer. Thus, the discovery of new molecules that selectively inhibit COX-2 and other inflammatory mediators is a current challenge in the medicinal chemistry field. 1-Phenylbenzimidazoles have shown potential COX inhibitory activity, because they can reproduce the interaction profile of known COX inhibitors. Therefore, in the present investigation a series of 1,2-diphenylbenzimidazoles (DPBI) with different aromatic substitutions in the para position were synthesized and their interaction with COX-2 and nitric oxide synthase, iNOS, was determined in silico, in vitro and in vivo. Compound 2-(4-bromophenyl)-1-(4-nitrophenyl)-1H-benzo[d]imidazole showed the best inhibition towards COX-2, while compounds N-(4-(2-(4-bromophenyl)-1H-benzo[d]imidazol-1-yl)phenyl)acetamide and N-(4-(2-(4-chlorophenyl)-1H-benzo[d]imidazol-1-yl)phenyl)acetamide diminished the production of NO in vitro. Additionally, they had a significant anti-inflammatory activity in vivo when given orally.

Synthesis of Biologically Active Molecules through Multicomponent Reactions

Focusing on the literature progress since 2002, the present review explores the highly significant role that multicomponent reactions (MCRs) have played as a very important tool for expedite synthesis of a vast number of organic molecules, but also, highlights the fact that many of such molecules are biologically active or at least have been submitted to any biological screen. The selected papers covered in this review must meet two mandatory requirements: (1) the reported products should be obtained via a multicomponent reaction; (2) the reported products should be biologically actives or at least tested for any biological property. Given the diversity of synthetic approaches utilized in MCRs, the highly diverse nature of the biological activities evaluated for the synthesized compounds, and considering their huge structural variability, much of the reported data are organized into concise schemes and tables to facilitate comparison, and to underscore the key points of this review.

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.