Coumarin-based drugs: a patent review (2008 -- present)

PIDA-promoted metal-free [3 + 2] heteroannulation of β-ketothioamides with 4-hydroxy coumarins: chemo-/regioselective access to furo[3,2-c]chromen-4-ones at room temperature

Herein, we report a viable protocol to access furo[3,2-c]chromen-4-ones by engaging easily accessible 4-hydroxy coumarins as a three-atom CCO unit and thioamides as a C2 coupling partner, mediated by phenyliodine(III) diacetate (PIDA) at room temperature in a highly efficient and pot-/step-economical manner. This strategy not only avoids potential toxicity and tiresome workup conditions, but also features operational simplicity, a broad substrate scope, good functional group tolerance, high yields, easy scalability and exclusive selectivity. A mechanistic study has shown that this metal-free reaction is triggered by PIDA via activation of the β-carbon of 4-hydroxy coumarin, followed by a nucleophilic addition/intramolecular cyclization/dethiohydration cascade. High-resolution mass spectra (HRMS) study confirms the key intermediates involved during the course of the reaction, elucidating the reaction pathways, and demonstrates the excellent regio- and chemoselectivity of this approach.

Synthesis and Fluorescence Properties of Imidazopyridine-Linked Coumarins via Tandem C(sp2)-H Functionalization/Decarboxylation Reaction

A catalyst-, oxidant-free and green synthetic route for direct access to a series of novel imidazopyridine-linked coumarins has been devised through tandem C(sp2)-H functionalization/decarboxylation reaction in ethyl acetate as a sustainable medium. Moreover, the utilities of ensured products in further organic synthesis were conducted by Suzuki-Miyaura and Sonogashira cross-coupling reactions. The fluorescence characteristics of the produced molecules are appropriate, and the synthesized scaffolds could promisingly garner future attention in clinical diagnostics and bioimaging research.

Anticancer mechanism of coumarin-based derivatives

The structural motif of coumarins is related with various biological activities and pharmacological properties. Both natural coumarin extracted from various plants or a new coumarin derivative synthesized by modification of the basic structure of coumarin, in vitro experiments showed that coumarins are a promising class of anti-tumor agents with high selectivity. Cancer is a complex and multifaceted group of diseases characterized by the uncontrolled and abnormal growth of cells in the body. This review focuses on the anticancer mechanism of various coumarins synthesized and isolated in more than a decade. Isopentenyloxycoumarins inhibit angiogenesis by reducing CCl2 chemokine levels. Ferulin C is a potent colchicine-binding agent that destabilizes microtubules, exhibiting antiproliferative and anti-metastatic effects in breast cancer cells through PAK1 and PAK2-mediated signaling. Trimers of triphenylethylene-coumarin hybrids demonstrated significant proliferation inhibition in HeLa, A549, K562, and MCF-7 cell lines. Platinum(IV) complexes with 4-hydroxycoumarin have the potential for high genotoxicity against tumor cells, inducing apoptosis in SKOV-3 cells by up-regulating caspase 3 and caspase 9 expression. Derivatives of 3-benzyl coumarin seco-B-ring induce apoptosis, mediated through the PI3K/Akt/mTOR signaling pathway. Sesquiterpene coumarins inhibit the efflux pump of multidrug resistance-associated protein. Coumarin imidazolyl derivatives inhibit the aromatase enzyme, a major contributor to estrogen overproduction in estrogen-dependent breast cancer.

Gaafar AR, Gurusamy R, Akbar I. Synthesis of anthraquinone-connected coumarin derivatives via grindstone method and their evaluation of antibacterial, antioxidant, tyrosinase inhibitory activities with molecular docking, and DFT calculation studies

Anthraquinones and coumarins have excellent pharmacological activities and are an important class of natural plant metabolites with various biological activities. In this study, anthraquinone-9,10-dione and coumarin derivatives were combined to develop a novel anthraquinone-connected coumarin-derivative sequence. The synthesised novel anthraquinone-connected coumarin derivatives (1a-t) were screened for in vitro antibacterial, antioxidant, and tyrosinase inhibitory activities. The antibacterial activities of the synthesised compounds (1a-t) were tested against both gram-positive and gram-negative bacteria. Specifically, compound 1t was more active against E. aerogenes than ciprofloxacin. With regard to antioxidant activity, compound 1o (50.68 % at 100 μg/mL) was highly active compared to the other compounds, whereas it was less active than the standard BHT (76.74 % at 100 μg/mL). In terms of compound 1r (9.31 ± 0.45 μg/mL) was highly active against tyrosinase inhibitory activity compared with kojic acid (10.42 ± 0.98 μg/mL). In the molecular docking study, compound 1r had a higher docking score (-8.8 kcal mol-1) than kojic acid (-1.7 kcal mol-1). DFT calculations were performed to determine the energy gap of highly active compound 1r (ΔE = 0.11) and weakly active compound 1a (ΔE = 0.12). In this study, we found that every molecule displayed significant antibacterial, antioxidant, and tyrosinase inhibitory properties. Based on these reports, compounds 1r and 1t may act as multi-target agents.

Evaluation of Antibacterial Activity against Nosocomial Pathogens of an Enzymatically Derived α-Aminophosphonates Possessing Coumarin Scaffold

The purpose of the present study was to evaluate the synergistic effect of two important pharmacophores, coumarin and α-amino dimethyl phosphonate moieties, on antimicrobial activity against selected strains of multidrug-resistant nosocomial pathogenic bacteria. The previously developed enzyme-catalysed Kabachnik-Fields protocol allowed us to obtain the studied compounds with high yields which were free from metal impurities. The structure-activity relationship revealed that inhibitory activity is strongly related to the presence of the trifluoromethyl group (CF3-) in the coumarin scaffold. MIC and MBC studies carried out on six selected pathogenic bacterial strains (Gram-positive pathogenic Staphylococcus aureus (ATCC 23235) strain, as well as on Gram-negative Acinetobacter baumannii (ATCC 17978), Pseudomonas aeruginosa (ATCC 15442), Enterobacter cloacae (ATCC 49141), Porphyromonas gingivalis (ATCC 33277), and Treponema denticola (ATCC 35405)) have shown that tested compounds show a strong bactericidal effect at low concentrations. Among all agents investigated, five exhibit higher antimicrobial activity than those observed for commonly used antibiotics. It should be noted that all the compounds tested showed very high activity against S. aureus, which is the main source of nosocomial infections that cause numerous fatalities. Furthermore, we have shown that the studied coumarin-based α-aminophosphonates, depending on their structural characteristics, are non-selective and act efficiently against various Gram-positive and Gram-negative pathogens, which is of great importance for hospitalised patients.

Coumarin Based Fluorescent Probe for Detecting Heavy Metal Ions

Heavy metals such as Iron, Copper, and Zinc are micro-essential trace metal and involve animportant biological role, but it quickly turns toxic at exceeding the permissible limit, causing gastrointestinal irritation, liver, bone, and kidney damage, as well as disorders including Wilson's, Parkinson's, and Alzheimer's. It is important to detect the metal ions as well as their concentration quickly and affordable cost using organic probes. Among the organic probes,the coumarin fluorescent probe shows a very prominent candidate with heavy metal ions. Therefore, in the present review, we reviewed the very recent literature the identify the heavy metals using modified coumarin fluorescent probes. Readers will get information quickly about the method of preparation of modified coumarin core and their use as fluorescent probes with heavy metals using absorption and emission spectroscopic methods along with the probable mechanistic pathway of detection.

Effective Synthesis and Biological Evaluation of Dicoumarols: Preparation, Characterization, and Docking Studies

A series of 3,3-arylidene bis (4-hydroxycoumarins) 2 were synthesized by the reaction of aromatic aldehydes with 4-hydroxycoumarin using dodecylbenzenesulfonic acid as Brønsted acid-surfactant catalyst in aqueous media and under microwave irradiation. The present method is operationally simple and the use of water as the reaction medium makes the process environmentally benign. The epoxydicoumarins 5 were then obtained with a good yield by heating 3,3'-arylidenebis-4-hydroxycoumarins 2 in acetic anhydride. Techniques such as elemental analysis, ¹H, ¹³C-¹H NMR, and infrared spectroscopy were employed to characterize these compounds. The synthesized compounds displayed good antibacterial potential against Escherichia coli (ATCC 25988), Pseudomonas aeruginosa (ATCC 27853), Klebsilla pneumonia (ATCC 700603), Staphylococcus aureus (ATCC 29213), methicillin-resistant Staphylococcus aureus (ATCC 43300) and Candida albicans (ATCC 14053). The MIC values of 23 mg/mL for compound 5e against Escherichia coli (ATCC 25988) and 17 mg/mL for 2a were observed. Furthemore, a molecular docking simulation has been performed to evaluate the antibacterial activities and the probable binding modes of the studied compounds 2a-f and 5a-g toward the active sites of a series of well known antibacterial targets. Among the investigated compounds, the binding modes and docking scores demonstrate that 2a has the most antibacterial and antifungal activities. Additionally, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS has been tested for their ability to scavenge hydrogen peroxide and free radicals. According to our results, these compounds exhibit excellent radical scavenging properties. Furthermore, compounds 2-5 were evaluated for anti-inflammatory activity by indirect haemolytic and lipoxygenase inhibition assays and revealed good activity.

Enzymatic Synthesis of a Novel Coumarin Aminophosphonates: Antibacterial Effects and Oxidative Stress Modulation on Selected E. coli Strains

The objective of the present study was to evaluate the synergistic effect of two important pharmacophores, coumarin and α-amino dimethyl phosphonate moieties, on antimicrobial activity toward selected LPS-varied E. coli strains. Studied antimicrobial agents were prepared via a Kabachnik-Fields reaction promoted by lipases. The products were provided with an excellent yield (up to 92%) under mild, solvent- and metal-free conditions. A preliminary exploration of coumarin α-amino dimethyl phosphonate analogs as novel antimicrobial agents was carried out to determine the basic features of the structure responsible for the observed biological activity. The structure-activity relationship revealed that an inhibitory activity of the synthesized compounds is strongly related to the type of the substituents located in the phenyl ring. The collected data demonstrated that coumarin-based α-aminophosphonates can be potential antimicrobial drug candidates, which is particularly crucial due to the constantly increasing resistance of bacteria to commonly used antibiotics.

Filamentous temperature sensitive mutant Z: a putative target to combat antibacterial resistance

In the pre-antibiotic era, common bacterial infections accounted for high mortality and morbidity. Moreover, the discovery of penicillin in 1928 marked the beginning of an antibiotic revolution, and this antibiotic era witnessed the discovery of many novel antibiotics, a golden era. However, the misuse or overuse of these antibiotics, natural resistance that existed even before the antibiotics were discovered, genetic variations in bacteria, natural selection, and acquisition of resistance from one species to another consistently increased the resistance to the existing antibacterial targets. Antibacterial resistance (ABR) is now becoming an ever-increasing concern jeopardizing global health. Henceforth, there is an urgent unmet need to discover novel compounds to combat ABR, which act through untapped pathways/mechanisms. Filamentous Temperature Sensitive mutant Z (FtsZ) is one such unique target, a tubulin homolog involved in developing a cytoskeletal framework for the cytokinetic ring. Additionally, its pivotal role in bacterial cell division and the lack of homologous structural protein in mammals makes it a potential antibacterial target for developing novel molecules. Approximately 2176 X-crystal structures of FtsZ were available, which initiated the research efforts to develop novel antibacterial agents. The literature has reported several natural, semisynthetic, peptides, and synthetic molecules as FtsZ inhibitors. This review provides valuable insights into the basic crystal structure of FtsZ, its inhibitors, and their inhibitory activities. This review also describes the available in vitro detection and quantification methods of FtsZ-drug complexes and the various approaches for determining drugs targeting FtsZ polymerization.

Photosynthesis of 3-Alkylated Coumarins from Carboxylic Acids Catalyzed by a Na2S-Based Electron Donor-Acceptor Complex

A simple and practical electron donor-acceptor (EDA) strategy to synthesize various 3-alkylated coumarins from easily available coumarins and naturally abundant carboxylic acids under photocatalyst-, oxidant-, and additive-free and mild conditions is reported. Using Na₂S as the catalytic electron donor, a series of primary, secondary, and tertiary carbon radicals can be efficiently generated, and the EDA complex can be regenerated without an alkaline additive.

Antiseizure Effects of Scoparone, Borneol and Their Impact on the Anticonvulsant Potency of Four Classic Antiseizure Medications in the Mouse MES Model-An Isobolographic Transformation

Numerous botanical drugs containing coumarins and terpenes are used in ethnomedicine all over the world for their various therapeutic properties, especially those affecting the CNS system. The treatment of epilepsy is based on antiseizure medications (ASMs), although novel strategies using naturally occurring substances with confirmed antiseizure properties are being developed nowadays. The aim of this study was to determine the anticonvulsant profiles of scoparone (a simple coumarin) and borneol (a bicyclic monoterpenoid) when administered separately and in combination, as well as their impact on the antiseizure effects of four classic ASMs (carbamazepine, phenytoin, phenobarbital and valproate) in the mouse model of maximal electroshock-induced (MES) tonic-clonic seizures. MES-induced seizures were evoked in mice receiving the respective doses of the tested natural compounds and classic ASMs (when applied alone or in combinations). Interactions for two-drug and three-drug mixtures were assessed by means of isobolographic transformation of data. Polygonograms were used to illustrate the types of interactions occurring among drugs. The total brain content of ASMs was measured in mice receiving the respective drug treatments with fluorescent polarization immunoassay. Scoparone and borneol, when administered alone, exerted anticonvulsant properties in the mouse MES model. The two-drug mixtures of scoparone with valproate, borneol with phenobarbital and borneol with valproate produced synergistic interactions in the mouse MES model, while the remaining tested two-drug mixtures produced additivity. The three-drug mixtures of scoparone + borneol with valproate and phenobarbital produced synergistic interactions in the mouse MES model. Verification of total brain concentrations of valproate and phenobarbital revealed that borneol elevated the total brain concentrations of both ASMs, while scoparone did not affect the brain content of these ASMs in mice. The synergistic interaction of scoparone with valproate observed in the mouse MES model is pharmacodynamic in nature. Borneol elevated the brain concentrations of the tested ASMs, contributing to the pharmacokinetic nature of the observed synergistic interactions with valproate and phenobarbital in the mouse MES model.

Design, synthesis, anti-acetylcholinesterase evaluation and molecular modelling studies of novel coumarin-chalcone hybrids

The major enzyme responsible for the hydrolytic breakdown of the neurotransmitter acetylcholine (ACh) is acetylcholinesterase (AChE). Acetylcholinesterase inhibitors (AChEIs) are the most prescribed class of medications for the treatment of Alzheimer's disease (AD) and dementia. The limitations of available therapy, like side effects, drug tolerance, and inefficacy in halting disease progression, drive the need for better, more efficacious, and safer drugs. In this study, a series of fourteen novel chalcone-coumarin derivatives (8a-n) were designed, synthesized and characterized by spectral techniques like FT-IR, NMR, and HR-MS. Subsequently, the synthesized compounds were tested for their ability to inhibit acetylcholinesterase (AChE) activity by Ellman's method. All tested compounds showed AChE inhibition with IC50 value ranging from 0.201 ± 0.008 to 1.047 ± 0.043 μM. Hybrid 8d having chloro substitution on ring-B of the chalcone scaffold showed relatively better potency, with IC50 value of 0.201 ± 0.008 μM compared to other members of the series. The reference drug, galantamine, exhibited an IC50 at 1.142 ± 0.027 μM. Computational studies revealed that designed compounds bind to the peripheral anionic site (PAS), the catalytic active site (CAS), and the mid-gorge site of AChE. Putative binding modes, ligand-enzyme interactions, and stability of the best active compound are studied using molecular docking, followed by molecular dynamics (MD) simulations. The cytotoxicity of the synthesised derivatives was determined using the MTT test at three concentrations (100 g/mL, 500 g/mL, and 1 mg/mL). None of the chemicals had a significant effect on the body at the highest dose of 1 mg/mL.Communicated by Ramaswamy H. Sarma.

S, Joy MN. Substituted benzocoumarin derivatives: synthesis, characterization, biological activities and molecular docking with ADME studies

Herein, an efficient and convenient method for the synthesis of 4-(substitutedphenyl)-1,2-dihydro-2-oxo-6-(2-oxo-2H-benzo[g]chromen-3-yl)pyridine-3-carbonitrile derivatives have been reported using ammonium acetate as catalyst. The structures of synthesized compounds were confirmed using FT-IR, 1H, 13C-NMR and LC-MS spectroscopic techniques. The synthesized compounds have been evaluated for antibacterial activity against bacterial strains by agar diffusion method at different concentrations. Further, all the targeted compounds were screened for anti-oxidant and anti-cancer studies by DPPH and MTT assay methods at different concentrations. Compound 4b displayed good antioxidant and anticancer (against MCF-7 cell line) activity. Further, the binding capability for the synthesized compounds (4a–j) was analyzed by molecular docking studies using human peroxiredoxin 5 (PDB ID: 1HD2) and P38 MAP kinase (PDB ID: 1OUK) protein. Further, the physicochemical properties were analysed from ADME studies respectively.

Synthesis and Evaluation of Coumarin-Chalcone Derivatives as α-Glucosidase Inhibitors

Coumarin and chalcone, two important kinds of natural product skeletons, both exhibit α-glucosidase inhibitory activity. In this work, coumarin-chalcone derivatives 3 (a∼v) were synthesized, and their α-glucosidase inhibitory activity was screened. The results showed that all synthetic derivatives (IC50: 24.09 ± 2.36 to 125.26 ± 1.18 μM) presented better α-glucosidase inhibitory activity than the parent compounds 3-acetylcoumarin (IC50: 1.5 × 105 μM) and the positive control acarbose (IC50: 259.90 ± 1.06 μM). Among them, compound 3t displayed the highest α-glucosidase inhibitory activity (IC50: 24.09 ± 2.36 μM), which was approximately 10 times stronger than that of acarbose. The kinetic assay of 3t (KI = 18.82 μM, KIS = 59.99 μM) revealed that these compounds inhibited α-glucosidase in a mixed-type manner. Molecular docking was used to simulate the interaction between α-glucosidase and compound 3t.

Modern metal-catalyzed and organocatalytic methods for synthesis of coumarin derivatives: a review

Coumarin is an important pharmaceutical structural motif, abundantly found in numerous commonly used drugs. Compounds containing this core show a broad spectrum of medicinal properties and biological activities. The increasing importance and wide usages of coumarin derivatives have drawn attention to its synthetic methods, among which metal-catalyzed and organocatalytic methods have proved the most effective. Several metal-catalyzed and/or organocatalytic synthetic strategies for coumarin have been investigated and reported in recent decades. This review focuses on more recent reports on catalysis methods for synthesizing coumarin and coumarin-like structures (including light-mediated methods and nano-catalysts), exploring the mechanistic aspects, simplicity, efficiency, repeatability, and other advantages and disadvantages of these methods.

Structure-Activity Relationship of Benzofuran Derivatives with Potential Anticancer Activity

Simple Summary

Cancer is the leading cause of death worldwide and responsible for killing approximately 10 million people per year. Fused heterocyclic ring systems such as benzofuran have emerged as important scaffolds with many biological properties. Furthermore, derivatives of benzofurans demonstrate a wide range of biological and pharmacological activities, including anticancer properties. The main aim of this review is to highlight and discuss the contribution of benzofuran derivatives as anticancer agents by considering and discussing the chemical structure of 20 different compounds. Evaluating the chemical structure of these compounds will guide future medicinal chemists in designing new drugs for cancer therapy that might give excellent results in in vivo/in vitro applications.

Abstract

Benzofuran is a heterocyclic compound found naturally in plants and it can also be obtained through synthetic reactions. Multiple physicochemical characteristics and versatile features distinguish benzofuran, and its chemical structure is composed of fused benzene and furan rings. Benzofuran derivatives are essential compounds that hold vital biological activities to design novel therapies with enhanced efficacy compared to conventional treatments. Therefore, medicinal chemists used its core to synthesize new derivatives that can be applied to a variety of disorders. Benzofuran exhibited potential effectiveness in chronic diseases such as hypertension, neurodegenerative and oxidative conditions, and dyslipidemia. In acute infections, benzofuran revealed anti-infective properties against microorganisms like viruses, bacteria, and parasites. In recent years, the complex nature and the number of acquired or resistant cancer cases have been largely increasing. Benzofuran derivatives revealed potential anticancer activity with lower incidence or severity of adverse events normally encountered during chemotherapeutic treatments. This review discusses the structure–activity relationship (SAR) of several benzofuran derivatives in order to elucidate the possible substitution alternatives and structural requirements for a highly potent and selective anticancer activity.

Direct Synthesis of Coumarin Derivatives from Alkynoic Esters via Dual-organocatalysis

An efficient synthetic method for coumarin derivatives was developed using a dual-organocatalytic reaction. A combination of p-toluenesulfonic acid monohydrate and piperidine was found to efficiently catalyze the cyclization between salicylaldehydes and alkynoic esters to give various coumarin derivatives in good yield and high selectivity. Mechanistic and kinetic data suggested that the conjugate addition between piperidine and alkynoic esters played a crucial role in the reaction mechanism.

Dual Role of Oxoaldehydes: Divergent Synthesis of 3-Aryl- and 3-Aroylcoumarins

A facile and efficient synthetic approach to various valuable 3-aryl- and 3-aroylcoumarins by the direct arylation and aroylation of coumarins with glyoxals in a metal-free manner is presented. The aryl glyoxal is for the first time recognized to serve as an aryl surrogate in addition to its role as an aroyl transfer reagent via a simple switch in reaction conditions. The approach accommodates a broad substrate scope and high yields of the two types of cross-coupling reactions starting from identical starting materials.

Novel coumarin derivatives containing a triazole moiety: A study on synthesis, cytotoxicity, membrane dysfunction, apoptosis, cell cycle, and antiangiogenic studies

BACKGROUND

Coumarin is a functional compound with a pronounced wide range of biological activities and has recently been shown to have anticancer effects on various human cancer cells. Cisplatin is widely used in treating many cancers, but its effectiveness is limited due to acquired resistance and dose-related side effects.

OBJECTIVE

This study aimed to reveal the chemosensitizing ability of novel synthesized coumarin-triazole hybrid compounds (3a-f) compared to the cisplatin in A549, MCF-7, and HeLa cancer cells.

METHODS

Cytotoxicity was determined by MTT assay. Lactate dehydrogenase (LDH), antioxidant/oxidant status, DNA fragmentation were determined spectrophotometrically using commercial kits. Muse™ Cell Analyzer was used to assess cell cycle progression. Pro/anti-apoptotic gene expressions were determined by Real-Time qPCR. The antiangiogenic activity was determined by VEGF expression and Hen's chorioallantoic membrane model.

RESULTS

Compounds 3c, -d, -e, and -f potentiated the cisplatin-induced cytotoxicity through the increased LDH release and DNA fragmentation, induced G2/M cell cycle arrest, overproduction of oxidative stress, and decrease of cellular antioxidant levels. These compounds combined with cisplatin caused upregulation in the pro-apoptotic Bax, Bıd, caspase-3, caspase-8, caspase-9, Fas, and p53 gene expressions while downregulating anti-apoptotic DFFA, NFkB1, and Bcl2 gene expressions. These combinations caused vascular loss and a reduction in VEGF expression.

CONCLUSION

These results suggest that a combinational regimen of coumarin compounds with cisplatin could be enhancing the effect of cisplatin in A549 cells. Besides, considering compounds have relatively low toxicity in normal cells, they decrease the dose requirement of cisplatin in cancer treatments.

From natural products to HDAC inhibitors: An overview of drug discovery and design strategy

Histone deacetylases (HDACs) play a key role in the homeostasis of protein acetylation in histones and have recently emerged as a therapeutic target for numerous diseases. The inhibition of HDACs may block angiogenesis, arrest cell growth, and lead to differentiation and apoptosis in tumour cells. Thus, HDAC inhibitors (HDACi) have received increasing attention and many of which are developed from natural sources. In the past few decades, naturally occurring HDACi have been identified to have potent anticancer activities, some of which have demonstrated promising therapeutic effects on haematological malignancies. In this review, we summarized the discovery and modification of HDAC inhibitors from natural sources, novel drug design that uses natural products as parent nuclei, and dual target design strategies that combine HDAC with non-HDAC targets.

Phytochemical and pharmacological uses of medicinal plants to treat cancer: A case study from Khyber Pakhtunkhwa, North Pakistan

ETHNOPHARMACOLOGICAL RELEVANCE

Cancer is the top death causing disease in the world, due to its occurrence through various mechanism and form. Medicinal plants have been extensively used for the purifications and isolations of phytochemicals for the treatment and prevention of cancer.

OBJECTIVES

Consequently, this research was designed to document the traditional practices of anti-cancer plants and its phytochemical essay across the districts of KP, Pakistan.

MATERIALS AND METHODS

Semi-structured interviews were conducted in 24 districts from the informants mostly the traditional herbalists (key informants). The information were compared with the publish data using various authentic search engines including, google, researchgate, google scholar and NCBI.

RESULTS

One hundred and fifty-four (154) anti-cancer plants were recognized belonging to 69 families among all, Lamiaceae (13 sp.), Asteraceae (12 sp.) and Solanaceae (9 sp.) were the preferred families. The local inhabitants in the area typically prepare ethnomedicinal recipes from leaves (33.70%) and whole plants (23.37%) in the form of decoction and powder (24.67%), respectively. Herbs stayed the most preferred life form (61.68%) followed by shrub (21.4%). Similarly, breast (29.22%) and lung cancer (14.83%) was the common disease type. Literature study also authorize that, the medicinal plants of the research area were rich in phytochemical like quercetin, coumarine, kaempferol, apigenin, colchicine, alliin, rutin, lupeol, allicin, berbarine, lutolin, vanilic acid, urocilic acid and solamargine have revealed significant activates concerning the cancer diseases, that replicating the efficacy of these plants as medicines.

CONCLUSION

The Khyber Pakhtunkhwa is rural area and the local inhabitants have very strong traditional knowledge about the medicinal plants for different diseases like cancer. The medicinal plants for significant ranked disorder might be pharmacologically and phtyochemicaly explored to demonstrate their efficacy. Moreover, the local flora especially medicinal plants facing overgrazing, overexploitation and inappropriate way of collection, however, proper management strategies like reforestation, controlled grazing, proper permission from concerned department and rangeland strategies among others may be assumed to enhance the proper usage of medicinal plants.

Therapeutic Journey and Recent Advances in the Synthesis of Coumarin Derivatives

BACKGROUND

Coumarin is an oxygen-containing compound in medicinal chemistry. Coumarin plays an important role in both natural systems like plants and also in synthetic medicinal applications as drug molecules. Many structurally different coumarin compounds were found to show a big range of similarity with the vital molecular targets for their pharmacological action and small modifications in their structures resulted insignificant changes in their biological activities.

OBJECTIVE

This review gives detailed information about the studies of the recent advances in various pharmacological aspects of coumarins.

METHOD

Various oxygen-containing heterocyclic compounds represented remarkable biological significances. The fused aromatic oxygen-heterocyclic nucleus is able to change its electron density; thus changing the chemical, physical and biological properties respectively due to its multiple binding modes with the receptors, which play crucial role in pharmacological screening of drugs. A number of heterocyclic compounds have been synthesized which have their nucleus derived from various plants and animals. In coumarins, benzene ring is fused with pyrone nucleus which provides stability to the nucleus. Coumarins have shown a wide range of pharmacological activities such as anti-tumour, anti-coagulant, anti-inflammatory, anti-oxidant, antiviral, anti-malarial, anti-HIV and antimicrobial activity etc. Results: Reactive oxygen species like superoxide anion, hydroxyl radical and hydrogen peroxide are a type of unstable molecule that contains oxygen, which reacts with other molecules in the cell during the metabolism process but it may produce cytotoxicity when reactive oxygen species increase in number, by the damage of biological macromolecules. Hydroxyl radical (˙OH), is a strong oxidizing agent and it is responsible for the cytotoxicity by oxygen in different plants, animals and other microbes. coumarin is the oldest and effective compound having antimicrobial activity, anti-inflammatory, antioxidant, antidepressant activity, analgesic, anticonvulsant activity, etc. Naturally existing coumarin compounds act against SARS-CoV-2 by preventing viral replication through the targeting on active site against the Mpro target protein.

CONCLUSION

This review highlights the different biological activities of coumarin derivatives. In this review we provide an updated summary of the researches which are related to recent advances in biological activities of coumarins analogue and their most recent activities against COVID -19. Natural compounds act as a rich resource for novel drug development against various SARS-CoV-2 viral strains including viruses like herpes simplex virus, influenza virus, human immunodeficiency virus, hepatitis B and C viruses, middle east respiratory syndrome and severe acute respiratory syndrome.

Excited State Complexes of Coumarin Derivatives

Furocoumarins are the useful derivatives of coumarin, and they act as skin photosensitizing material due to their exciting exciplex states. Dendrimers also form exciplexes when they contain coumarin as core and used for light harvesting. A number of ingredients in human nutrition contain coumarins. The apiaceae family is the most common example of this class that contains carrots, celery and parsley etc. Rutaceae family is also an important food source that contains coumarins and provides citrus food. Besides fruits and vegetables, beverages like coffee, wine, black and green tea also incorporates coumarin derivatives. Few coumarin dyes show absorption and one emission peak but it can show a double amplified spontaneous emission band due to the generation of super exciplexes in coumarins. Exciplex formation of different coumarin derivatives including 7-methoxy coumarin, 7-hydroxy coumarin show wide application in synthesis of various other derivatives and they can be used as dye due to their prominent fluorescence properties. Exciplexes and excimers of coumarin are widely used in lasers. Both singlet and triplet state exciplexes are considered. Thus a comprehensive review of excited state complexes of coumarin derivatives is discussed here with emphases on the interaction and overlap of the energy levels.

Novel inhibitors of eukaryotic elongation factor 2 kinase: In silico, synthesis and in vitro studies

Eukaryotic elongation factor 2 kinase (eEF2K) is an unusual alpha kinase whose expression is highly upregulated in various cancers and contributes to tumor growth, metastasis, and progression. More importantly, eEF2K expression is associated with poor clinical outcome and shorter patient survival in breast, lung and ovarian cancers. Therefore, eEF2K is an emerging molecular target for development of novel targeted therapeutics and precision medicine in solid cancers. Currently, there are not any available potent and specific eEF2K inhibitors for clinical translation. In this study, we designed and synthesized a series of novel compounds with coumarin scaffold with various substitutions and investigated their effects in inhibiting eEF2K activity using in silico approaches and in vitro studies in breast cancer cells. We utilized an amide substitution at position 3 on the coumarin ring with their pharmacologically active groups containing pyrrolidine, piperidine, morpholine and piperazine groups with (CH₂)₂ bridged for aliphatic amides. Due to their ability to form covalent binding to the target enzyme, we also investigated the effects of boron containing groups on functionalized coumarin ring (3 compounds) and designed novel aliphatic and aromatic derivatives of coumarin scaffolds (10 compounds) and phenyl ring with boron groups (4 compounds). The Glide/SP module of the Maestro molecular modeling package was used to perform in silico analysis and molecular docking studies. According to our combined results, structure activity relationship (SAR) was performed in detail. Among the newly designed, synthesized, and tested compounds, our in vitro findings revealed that several compounds displayed a highly effective eEF2K inhibition at submicromolar concentrations in in vitro breast cancer cells. In conclusion, we identified novel compounds that can be used as eEF2K inhibitors and that they should be further evaluated by in vivo preclinical tumor models studies for antitumor efficacy and clinical translation.

Activator free diastereoselective 1,3-dipolar cycloaddition: a quick access to coumarin based spiro multi heterocyclic adducts

A formal diastereoselective 1,3-dipolar cycloaddition of azomethine ylide and coumarin derivatives to construct coumarin based spiro multi heterocyclics has been described. The in situ generation of azo-ylide was achieved for various heterocyclic carbonyls (indenoquinoxaline and isatin). This transformation is also suitable for maleimide dipolarophiles for the synthesis of hydro-maleimide derivatives. These decarboxylative annulations neither required any catalyst nor any activator. Further the pure products were isolated by filtration from the reaction mixture after the reaction under ambient conditions.

A formal diastereoselective decarboxylative 1,3-dipolar cycloaddition of azomethine ylide and coumarins is achieved for the synthesis of spiro multi heterocyclic adducts without engaging any catalyst or activator in good yields.

Iridium(i) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrosilylation catalysts

A set of iridium(i) complexes of formula IrCl(κC,η²-I^RCou^R')(cod) or IrCl(κC, η²-BzI^RCou^R')(cod) (cod = 1,5-cyclooctadiene; Cou = coumarin; I = imidazolin-2-carbene; BzI = benzimidazolin-2-carbene) have beeen prepared from the corresponding azolium salt and [Ir(μ-OMe)(cod)]₂ in THF at room temperature. The crystalline structures of 4b and 5b show a distorted trigonal bipyramidal configuration in the solid state with a coordinated coumarin moiety. In contrast, an equilibrium between this pentacoordinated structure and the related square planar isomer is observed in solution as a consequence of the hemilability of the pyrone ring. Characterization of both species by NMR was achieved at the low and high temperature limits, respectively. In addition, the thermodynamic parameters of the equilibrium, ΔH_R and ΔS_R, were obtained by VT ¹H NMR spectroscopy and fall in the range 22-33 kJ mol^-1 and 72-113 J mol^-1 K^-1, respectively. Carbonylation of IrCl(κC,η²-BzI^TolCou^7,8-Me₂)(cod) resulted in the formation of a bis-CO derivative showing no hemilabile behaviour. The newly synthesised complexes efficiently catalyze the hydrosilylation of alkynes at room temperature with a preference for the β-(Z) vinylsilane isomer.

Asymmetric organocatalyzed synthesis of coumarin derivatives

Coumarin derivatives are essential scaffolds in medicinal and synthetic chemistry. Compounds of this class have shown important activities, such as anticancer and antiparasitic, besides the commercially available drugs. These properties led to the development of efficient and greener synthetic methods to achieve the 2H-chromen-2-one core. In this context, the advances in asymmetric organocatalyzed synthesis of coumarin derivatives are discussed in this review, according to the mode of activation of the catalyst.

Computational characterisation of Toxoplasma gondii FabG (3-oxoacyl-[acyl-carrier-protein] reductase): a combined virtual screening and all-atom molecular dynamics simulation study

Toxoplasma gondii is an opportunistic obligate parasite, ubiquitous around the globe with seropositivity rates that range from 10% to 90% and infection by the parasite of pregnant women causes pre-natal death of the foetus in most cases and severe neurodegenerative syndromes in some. No vaccine is currently available, and since drug-resistance is common among T. gondii strains, discovering lead compounds for drug design using diverse tactics is necessary. In this study, the sole constituent isoform of an enzymatic 3-oxoacyl-[acyl-carrier-protein] reduction step in an apicoplast-located fatty acid biosynthesis pathway was chosen as a possible drug target. FASII is prokaryotic therefore, targeting it would pose fewer side-effects to human hosts. After a homology 3D modelling of TgFabG, a high-throughput virtual screening of 9867 compounds, the elimination of ligands was carried out by a flexible ligand molecular docking and 200 ns molecular dynamics simulations, with additional DCCM and PC plot analyses. Molecular Dynamics and related post-MD analyses of the top 3 TgFabG binders selected for optimal free binding energies, showed that L2 maintained strong H-bonds with TgFabG and facilitated structural reorientation expected of FabGs, namely an expansion of the Rossmann Fold and a flexible lid capping. The most flexible TgFabG sites were the α7 helix (the flexible lid region) and the β4-α4 and β5-α6 loops. For TgFabG-L2, the movements of these regions toward the active site enabled greater ligand stability. Thus, L2 ("Skimmine"; PubChem ID: 320361), was ultimately selected as the optimal candidate for the discovery of lead compounds for rational drug design.Communicated by Ramaswamy H. Sarma.

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.

Water Soluble Coumarin Quaternary Ammonium Chlorides: Synthesis and Biological Evaluation

In the present study, coumarin-bearing three pyridinium and three tetra-alkyl ammonium salts were synthesized. The compounds were fully characterized by ¹ H- and ¹³ C-NMR, LC/MS and IR spectroscopic methods and elemental analyses. The cytotoxic properties of all compounds were tested against human liver cancer (HepG2), human colorectal cancer (Caco-2) and non-cancer mouse fibroblast (L-929) cell lines. Some compounds performed comparable cytotoxicity with standard drug cisplatin. Antibacterial properties of the compounds were tested against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis bacteria, but the compounds did not have any antibacterial effect against both bacteria. Enzyme inhibitory properties of all compounds were tested on the activities of human carbonic anhydrase I and II, and xanthine oxidase. All compounds inhibited both enzymes more effectively than standard drugs, acetazolamide and allopurinol, respectively. The biological evaluation results showed that ionic and water soluble coumarin derivatives are promising structures for further investigations especially on enzyme inhibition field.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

Xanthotoxin and umbelliferone attenuate cognitive dysfunction in a streptozotocin-induced rat model of sporadic Alzheimer's disease: The role of JAK2/STAT3 and Nrf2/HO-1 signalling pathway modulation

The aim of the present study was to assess the neuroprotective effects of xanthotoxin and umbelliferone in streptozotocin (STZ)-induced cognitive dysfunction in rats. Animals were injected intracerebroventricularly (ICV) with STZ (3 mg/kg) once to induce a sporadic Alzheimer's disease (SAD)-like condition. Xanthotoxin or umbelliferone (15 mg/kg, i.p.) were administered 5 hr after ICV-STZ and daily for 20 consecutive days. Xanthotoxin or umbelliferone prevented cognitive deficits in the Morris water maze and object recognition tests. In parallel, xanthotoxin or umbelliferone reduced hippocampal acetylcholinestrase activity and malondialdehyde level. Moreover, xanthotoxin or umbelliferone increased glutathione content. These coumarins also modulated neuronal cell death by reducing the level of proinflammatory cytokines (tumour necrosis factor-alpha and interleukin-6), inhibiting the overexpression of inflammatory markers (nuclear factor κB [NF-κB] and cyclooxygenase II), and upregulating the expression of NF-κB inhibitor (IκB-α). Interestingly, xanthotoxin diminished phosphorylated JAK2 and phosphorylated STAT3 protein expression, while umbelliferone markedly replenished nuclear factor erythroid-derived 2-like 2 (Nrf2) and haem oxygenase-1 (HO-1) levels. The current study provides evidence for the protective effect of xanthotoxin and umbelliferone in STZ-induced cognitive dysfunction in rats. This effect may be attributed, at least in part, to inhibiting acetylcholinestrase and attenuating oxidative stress, neuroinflammation and neuronal loss.

Effect of scopoletin on phagocytic activity of U937-derived human macrophages: Insights from transcriptomic analysis

Scopoletin is a botanical coumarin. Notably, scopoletin effect on phagocytic activity has not been addressed on transcriptomic level. Accordingly, this study investigated the effect of scopoletin on phagocytosis-linked gene transcription. Whole phagocytosis transcriptional profiling of stimulated U937-derived macrophages (SUDMs) in response to scopoletin as compared to non-treated SUDMs was studied. Regarding scopoletin effect on 92 phagocytosis-linked genes, 12 of them were significantly affected (p-value < .05). Seven genes were downregulated (CDC42, FCGR1A/FCGR1C, ITGA9, ITGB3, PLCE1, RHOD & RND3) and five were upregulated (DIRAS3, ITGA1, PIK3CA, PIK3R3 & PLCD1). Moreover, scopoletin enhanced phagocytic activity of SUDMs. The current results highlighted the potential use of scopoletin as immunity booster and as an adjuvant remedy in management of some autoimmune reactions. To the best of our knowledge, this is the first report that unravels the effect of scopoletin on phagocytosis via transcriptomic analysis.

Design, Synthesis, and Molecular Modeling Studies of Novel Coumarin Carboxamide Derivatives as eEF-2K Inhibitors

Eukaryotic elongation factor-2 kinase (eEF-2K) is an unusual alpha kinase commonly upregulated in various human cancers, including breast, pancreatic, lung, and brain tumors. We have demonstrated that eEF-2K is relevant to poor prognosis and shorter patient survival in breast and lung cancers and validated it as a molecular target using genetic methods in related in vivo tumor models. Although several eEF-2K inhibitors have been published, none of them have shown to be potent and specific enough for translation into clinical trials. Therefore, development of highly effective novel inhibitors targeting eEF-2K is needed for clinical applications. However, currently, the crystal structure of eEF-2K is not known, limiting the efforts for designing novel inhibitor compounds. Therefore, using homology modeling of eEF-2K, we designed and synthesized novel coumarin-3-carboxamides including compounds A1, A2, and B1-B4 and evaluated their activity by performing in silico analysis and in vitro biological assays in breast cancer cells. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) area results showed that A1 and A2 have interaction energies with eEF-2K better than those of B1-B4 compounds. Our in vitro results indicated that compounds A1 and A2 were highly effective in inhibiting eEF-2K at 1.0 and 2.5 μM concentrations compared to compounds B1-B4, supporting the in silico findings. In conclusion, the results of this study suggest that our homology modeling along with in silico analysis may be effectively used to design inhibitors for eEF-2K. Our newly synthesized compounds A1 and A2 may be used as novel eEF-2K inhibitors with potential therapeutic applications.

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

The study of coumarin dates back to 1820 when coumarin was first extracted from tonka bean by Vogel. Compounds containing coumarin backbone are a very important group of compounds due to their usage in pharmacy and medicine. Properties and biological activities of coumarin derivatives have a significant role in the development of new drugs. Therefore, many different methods and techniques are developed in order to synthesize coumarin derivatives. Coumarin derivatives could be obtained from different starting materials with various methods but with big differences in yield. This review summarized various methods, techniques and reaction conditions for synthesis of coumarins from different compounds such as aldehydes, phenols, ketones and carboxylic acids.

The Coumarin Derivative 5'-Hydroxy Auraptene Suppresses Osteoclast Differentiation via Inhibiting MAPK and c-Fos/NFATc1 Pathways

The phytochemical substances, coumarin derivatives, have demonstrated antiresorptive bone effects by suppressing osteoclast differentiation in vitro and in vivo. Recently, we have identified 5′-hydroxy auraptene (5′-HA), a coumarin derivative isolated from Lotus lalambensis Schweinf, as a novel stimulator for osteoblast differentiation. In this study, we investigated the effect of 5′-HA on osteoclast differentiation of mouse bone marrow (BM) cells. The effect of 5′-HA on BM cell proliferation and osteoclast differentiation was determined by measuring cell viability and tartrate-resistant acid phosphatase (TRAP) enzyme activity, quantification of TRAP⁺ multinucleated cells (TRAP⁺MNCs), and quantitative real-time PCR (qPCR) of osteoclastic gene expression. Regulation of NF-κB, c-Fos/NFATc1, and MAPK signaling pathways by 5′-HA during osteoclastogenesis was measured by the NF-κB reporter assay and Western blot analysis. 5′-HA significantly suppresses the receptor activator of NF-κB ligand (RANKL) induced osteoclast differentiation of BM cells in a dose-dependent manner. Consistently, treatment of BM cells with 5′-HA significantly inhibited RANKL-induced activation of NF-κB and c-Fos/NFATc1 pathways in a dose-dependent manner. Furthermore, RANKL-induced phosphorylation of ERK1/2, p-38, and JNK was significantly inhibited by 5′-HA in BM cells. In conclusion, we identified 5′-HA as a novel coumarin derivative that suppresses RANKL-induced osteoclastogenesis via inhibiting c-Fos/NFATc1 and MAPK signaling pathways.