Naturally Occurring Coumarins and Related Physiological Activities

Chemical library design, QSAR modeling and molecular dynamics simulations of naturally occurring coumarins as dual inhibitors of MAO-B and AChE

Coumarins are a highly privileged scaffold in medicinal chemistry. It is present in many natural products and is reported to display various pharmacological properties. A large plethora of compounds based on the coumarin ring system have been synthesized and were found to possess biological activities such as anticonvulsant, antiviral, anti-inflammatory, antibacterial, antioxidant as well as neuroprotective properties. Despite the wide activity spectrum of coumarins, its naturally occurring derivatives are yet to be investigated in detail. In the current study, a chemical library was created to assemble all chemical information related to naturally occurring coumarins from the literature. Additionally, a multi-stage virtual screening combining QSAR modeling, molecular docking, and ADMET prediction was conducted against monoamine oxidase B and acetylcholinesterase, two relevant targets known for their neuroprotective properties and 'disease-modifying' potential in Parkinson's and Alzheimer's disease. Our findings revealed ten coumarin derivatives that may act as dual-target drugs against MAO-B and AChE. Two coumarin candidates were selected from the molecular docking study: CDB0738 and CDB0046 displayed favorable interactions for both proteins as well as suitable ADMET profiles. The stability of the selected coumarins was assessed through 100 ns molecular dynamics simulations which revealed promising stability through key molecular interactions for CDB0738 to act as dual inhibitor of MAO-B and AChE. However, experimental studies are necessary to evaluate the bioactivity of the proposed candidate. The current results may generate an increasing interest in bioprospecting naturally occurring coumarins as potential candidates against relevant macromolecular targets by encouraging virtual screening studies against our chemical library.Communicated by Ramaswamy H. Sarma.

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.

4-methylumbelliferone (4-MU) enhances drought tolerance of apple by regulating rhizosphere microbial diversity and root architecture

The dwarfing rootstocks-mediated high-density apple orchard is becoming the main practice management. Currently, dwarfing rootstocks are widely used worldwide, but their shallow root system and drought sensitivity necessitate high irrigation requirements. Here, the root transcriptome and metabolome of dwarfing (M9-T337, a drought-sensitive rootstock) and vigorous rootstocks (Malus sieversii, a drought-tolerant species, is commonly used as a rootstock) showed that a coumarin derivative, 4-Methylumbelliferon (4-MU), was found to accumulate significantly in the roots of vigorous rootstock under drought condition. When exogenous 4-MU was applied to the roots of dwarfing rootstock under drought treatment, the plants displayed increased root biomass, higher root-to-shoot ratio, greater photosynthesis, and elevated water use efficiency. In addition, diversity and structure analysis of the rhizosphere soil microbial community demonstrated that 4-MU treatment increased the relative abundance of putatively beneficial bacteria and fungi. Of these, Pseudomonas, Bacillus, Streptomyces, and Chryseolinea bacterial strains and Acremonium, Trichoderma, and Phoma fungal strains known for root growth, or systemic resistance against drought stress, were significantly accumulated in the roots of dwarfing rootstock after 4-MU treatment under drought stress condition. Taken together, we identified a promising compound-4-MU, as a useful tool, to strengthen the drought tolerance of apple dwarfing rootstock.

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.

Coumarins as Fungal Metabolites with Potential Medicinal Properties

Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins’ biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins’ biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.

Molecular Insights into Coumarin Analogues as Antimicrobial Agents: Recent Developments in Drug Discovery

Simple Summary

Coumarins are a large family of benzopyrones, and more than 1300 coumarins have been reported to date. Natural, as well as synthetic, coumarins have demonstrated a diverse activity spectrum. On the other hand, the demands of the current health scenario witnessing morbidity and mortality due to microbial infections and multidrug-resistant bacterial strains, the well-reported phytochemical coumarin can be of interest. Some of the well-reported coumarin analogues as antimicrobial agents include β-lactum derivatives, coumarin-based 1,2,3-triazole compounds, the miconazole analogue, coumarin-substituted pyrazole hybrids, pyranocoumarin, coumarin−sulphonamide hybrids, pyranocoumarins, coumarin−sulphonamide derivatives, chromenylpyrazoles candidates, 3-amidocoumarins analogues, uracil−coumarin hybrids, indolinedione−coumarin hybrids, coumarin−imidazole hybrids, coumarin-fused pyrazolones and methyl thiazole derivatives, coumarin−theophylline hybrids, etc. In the present review, several methods for the synthesis of coumarin derivatives as antimicrobial agents are reported, along with structure−activity relationship (SAR) studies focusing on the developments reported since 2016.

Abstract

A major global health risk has been witnessed with the development of drug-resistant bacteria and multidrug-resistant pathogens linked to significant mortality. Coumarins are heterocyclic compounds belonging to the benzophenone class enriched in different plants. Coumarins and their derivatives have a wide range of biological activity, including antibacterial, anticoagulant, antioxidant, anti-inflammatory, antiviral, antitumour, and enzyme inhibitory effects. In the past few years, attempts have been reported towards the optimization, synthesis, and evaluation of novel coumarin analogues as antimicrobial agents. Several coumarin-based antibiotic hybrids have been developed, and the majority of them were reported to exhibit potential antibacterial effects. In the present work, studies reported from 2016 to 2020 about antimicrobial coumarin analogues are the focus. The diverse biological spectrum of coumarins can be attributed to their free radical scavenging abilities. In addition to various synthetic strategies developed, some of the structural features include a heterocyclic ring with electron-withdrawing/donating groups conjugated with the coumarin nucleus. The suggested structure−activity relationship (SAR) can provide insight into how coumarin hybrids can be rationally improved against multidrug-resistant bacteria. The present work demonstrates molecular insights for coumarin derivatives having antimicrobial properties from the recent past. The detailed SAR outcomes will benefit towards leading optimization during the discovery and development of novel antimicrobial therapeutics.

Polarized, V-Shaped, and Conjoined Biscoumarins: From Lack of Dipole Moment Alignment to High Brightness

Eleven conjoined coumarins possessing a chromeno[3,4-c]chromene-6,7-dione skeleton have been synthesized via the reaction of electron-rich phenols with esters of coumarin-3-carboxylic acids, catalyzed by either Lewis acids or 4-dimethylaminopyridine. Furthermore, Michael-type addition to angular benzo[f]coumarins is possible, leading to conjugated helical systems. Arrangement of the electron-donating amino groups at diverse positions on this heterocyclic skeleton makes it possible to obtain π-expanded coumarins with emission either sensitive to, or entirely independent of, solvent polarity with large Stokes shifts. Computational studies have provided a rationale for moderate solvatochromic effects unveiling the lack of collinearity of the dipole moments in the ground and excited states. Depending on the functional groups present, the obtained dyes are highly polarized with dipole moments of ∼14 D in the ground state and ∼20–25 D in the excited state. Strong emission in nonpolar solvents, in spite of the inclusion of a NO₂ group, is rationalized by the fact that the intramolecular charge transfer introduced into these molecules is strong enough to suppress intersystem crossing yet weak enough to prevent the formation of dark twisted intramolecular charge transfer states. Photochemical transformation of the dye possessing a chromeno[3,4-c]pyridine-4,5-dione scaffold led to the formation of a spirocyclic benzo[g]coumarin.

Comparison between the Biological Active Compounds in Plants with Adaptogenic Properties (Rhaponticum carthamoides, Lepidium meyenii, Eleutherococcus senticosus and Panax ginseng)

BACKGROUND

In the 1960s, research into plant adaptogens began. Plants with adaptogenic properties have rich phytochemical compositions and have been used by humanity since ancient times. However, it is not still clear whether the adaptogenic properties are because of specific compounds or because of the whole plant extracts. The aim of this review is to compare the bioactive compounds in the different parts of these plants.

METHODS

The search strategy was based on studies related to the isolation of bioactive compounds from Rhaponticum carthamoides, Lepidium meyenii, Eleutherococcus senticosus, and Panax ginseng. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

RESULTS

This review includes data from 259 articles. The phytochemicals isolated from Rhaponticum carthamoides, Lepidium meyenii, Eleutherococcus senticosus, and Panax ginseng were described and classified in several categories.

CONCLUSIONS

Plant species have always played an important role in drug discovery because their effectiveness is based on the hundreds of years of experience with folk medicine in different nations. In our view, there is great potential in the near future for some of the phytochemicals found in these plants species to become pharmaceutical agents.

A review on Coumarin derivatives as potent anti-Tuberculosis agent

BACKGROUND

Tuberculosis (TB) is an acute or chronic infectious disease caused by several species of Myco-bacterium, collectively called as tubercle bacilli or Mycobacterium tuberculosis complex. Around 10 million people get sick with tuberculosis (TB) each year. TB is the second leading cause of deaths today after HIV/AIDS. A serious problem in the context of MDR-TB, is the extensively drug-resistant TB which is an im-portant reason for the restricted chemotherapy in TB. Therefore, there is a need to explore new antitubercular (anti-TB) agents. Coumarin is an oxygen-containing heterocyclic compound and can be widely found in many natural products, and many of them display diverse biological activities.The wide spectrum of activities of coumarin molecules have intrigued the scientists to explore the natural coumarins and their synthetic deriva-tives for their potential as anti-TB drugs.

OBJECTIVE

The objective of this review is to emphasize on important coumarin analogs with anti-TB activities and their structure-activity relationships (SAR) for designing better anti-TB agents.

METHOD

Latest, authentic and published reports on various synthetic and natural coumarin derivatives and their anti-TB activities is being thoroughly studied and analyzed. The structural requirements of coumarins as anti-TB drugs have also been studied.

RESULT

Collection and compilation of reports on various synthetic and natural coumarin derivatives and their anti-TB activities is being done.

CONCLUSION

The study provides latest report on coumarin derivatives synthesized as anti-TB agent and wheth-er their activity depends on structural changes or not.

Multifunctional Therapeutic Potential of Phytocomplexes and Natural Extracts for Antimicrobial Properties

Natural products have been known for their antimicrobial factors since time immemorial. Infectious diseases are a worldwide burden that have been deteriorating because of the improvement of species impervious to various anti-infection agents. Hence, the distinguishing proof of antimicrobial specialists with high-power dynamic against MDR microorganisms is central to conquer this issue. Successful treatment of infection involves the improvement of new drugs or some common source of novel medications. Numerous naturally occurring antimicrobial agents can be of plant origin, animal origin, microbial origin, etc. Many plant and animal products have antimicrobial activities due to various active principles, secondary metabolites, or phytochemicals like alkaloids, tannins, terpenoids, essential oils, flavonoids, lectins, phagocytic cells, and many other organic constituents. Phytocomplexes' antimicrobial movement frequently results from a few particles acting in cooperative energy, and the clinical impacts might be because of the direct effects against microorganisms. The restorative plants that may furnish novel medication lead the antimicrobial movement. The purpose of this study is to investigate the antimicrobial properties of the phytocomplexes and natural extracts of the plants that are ordinarily being utilized as conventional medications and then recommended the chance of utilizing them in drugs for the treatment of multiple drug-resistant disease.

Biological and computational studies provide insights into Caesalphinia digyna Rottler stems

Caesalpinia digyna (Rottl.) (Family: Fabaceae) is an essential medicinal plant for it's conventional uses against a kind of human disorders. This research aims to investigate the antidiarrheal, antibacterial and antifungal properties of the methanol extract of the stems extracts of the C. digyna (MECD). The in vivo antidiarrheal activity of the stem extracts were evaluated by using castor oil-induced diarrhea, castor oil-induced enteropooling and charcoal induced intestinal transit in mice model. Besides, in vitro antimicrobial potentiality of MECD was investigated by the disc diffusion method. In silico activity of the isolated compounds were performed by Schrödinger-Maestro (Version 11.1) software. In addition, The ADME/T analysis and PASS prediction were implemented by using pass online tools. In the antidiarrheal investigation, the MECD exhibited a notable inhibition rate in all test approaches which were statistically significant (p < 0.05, p < 0.1, p < 0.01). MECD 400 mg/kg showed the maximum antidiarrheal potency in all the test methods. In vitro antimicrobial analysis unveiled that, MECD revealed higher potentiality against almost all pathogens and indicates dose-dependent activity against almost all the bacteria and fungi. In the case of in silico evaluation of anti-diarrheal, anti-bacterial and anti-fungal activity, all three isolated compounds met the pre-conditions of Lipinski's five rules for drug discovery. Pass predicted study also employed for all compounds. However, The chemical constituents of the C. digyna can be a potent source of anti-diarrheal, anti-bacterial and anti-fungal medicine and further modification and simulation studies are required to establish the effectiveness of bioactive compounds.

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Caesalpinia digyna is used to prepare therapeutic product "Geriforte".

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The pods, bark and seed pods of C. digyna contains high amount of tannins and flavonoids.

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Caesalpinia digyna is used to treat diarrhea, chronic fluxes, senile pruritis, tuberculosis, tonic disorder, and diabetes.

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This study is to validate the ethnopharmacological values of C. digyna stems.

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This is the first research work till now where, the stems of C. digyna have been studied.

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The results of in vivo, in vitro and in silico studies is comparatively closer to the standard drugs.

Coumarin hybrid derivatives as promising leads to treat tuberculosis: Recent developments and critical aspects of structural design to exhibit anti-tubercular activity

Tuberculosis (TB) is a highly contagious airborne disease with nearly 25% of the world's population infected with it. Challenges such as multi drug resistant TB (MDR-TB), extensive drug resistant TB (XDR-TB) and in rare cases totally drug resistant TB (TDR-TB) emphasizes the critical and urgent need in developing novel TB drugs. Moreover, the prolonged and multi drug treatment regime suffers a major drawback due to high toxicity and vulnerability in TB patients. This calls for intensified research efforts in identifying novel molecular scaffolds which can combat these issues with minimal side effects. In this pursuit, researchers have screened many bio-active molecules among which coumarin have been identified as promising candidates for TB drug discovery and development. Coumarins are naturally occurring compounds known for their low toxicity and varied biological activity. The biological spectrum of coumarin has intrigued medicinal researchers to investigate coumarin scaffolds for their relevance as anti-TB drugs. In this review we focus on the recent developments of coumarin and its critical aspects of structural design required to exhibit anti-tubercular (anti-TB) activity. The information provided will help medicinal chemists to design and identify newer molecular analogs for TB treatment and also broadens the scope of exploring future generation potent yet safer coumarin based anti-TB agents.

Synthesis and biological screening of thiosemicarbazones of substituted 3-acetylcoumarins having d-glucose moiety

Thiosemicarbazones 5a-j were synthesized with yields of 45-68% by condensation of 3-acetylcoumarins 3a-j and tetra-O-acetyl-β-d-thiosemicarbazide 4. All obtained thiosemicarbazones were screened for anti-microorganic activities against bacteria (B. subtilis, S. aureus, S. epidermidis, E. coli, P. aeruginosa, K. pneumoniae, S. typhimurium) and fungi (A. niger, C. albicans, S. cerevisiae, and A. flavus). Some compounds had significant inhibitory activity with MICs of 0.78-3.125 μM in comparison with 5a, including 5e,h,i for S. aureus, and 5c,f,i for S. epidermidis (Gram-(+) bacteria), 5c,f,g for E.coli, 5f for K. pneumoniae, 5b,c,g for P. aeruginosa, and 5i for S. typhimurium (Gram-(-) bacteria), 5d,h,i for A. niger, 5i for A. flavus, 5b,d,e,h for C. albicans, and 5i for S. cerevisiae. Compounds exhibited excellent activity against tested microorganism with MIC = 0.78 μM, including 5h,i (against S. aureus), 5h (against C. albicans), and 5i (against S. cerevisiae).

The Interplay between Solvation and Stacking of Aromatic Rings Governs Bright and Dark Sites of Benzo[g]coumarins

Coumarins are classic, strongly polarized fluorophores with multiple applications, and significant efforts have been put into modifying their emission characteristics and elucidating their photophysics. Expecting that π-expansion of these donor-acceptor chromophores could modify their ground- and excited-state characteristics, the authors performed combined, detailed photophysical and computational studies of linearly π-expanded coumarins, that is, 8-dialkylamino-3-carboxyalkyl-benzo[g]coumarins. The investigation led to the conclusion that emission is only possible thanks to the stabilizing effect of the solvent and that breaking of the lactone ring leads to the conical intersection with the ground state and induces the radiationless decay of the electronic excitation. Aiming at the fine-tuning the excited state properties through the construction of covalently linked dye assemblies, the authors designed and synthesized a new bis(benzo[g]coumarin), built from two similar moieties that exhibit different degrees of polarization due to the electron donor at position 8: one possesses a dialkylamino, and the other a weaker amide donor. Comprehensive studies have shown that the observed weak fluorescence of the system is the result of the interplay between the solvation-induced separation of the benzo[g]coumarin moieties, which stabilizes the emitting locally excited singlet state and the π-stacking interactions, favoring their sandwiched orientation and leading to the non-emissive charge-transfer state.

Coumarins: antifungal effectiveness and future therapeutic scope

The antifungals that are in current clinical practice have a high occurrence of a side effect and multidrug resistance (MDR). Researchers across the globe are trying to develop a suitable antifungal that has minimum side effect as well as no MDR issues. Due to serious undesired effects connected with individual antifungals, it is now necessary to introduce novel and effective drugs having numerous potentials to regulate complex therapeutic targets of several fungal infections simultaneously. Thus, by taking a lead from this subject, synthesis of potent antifungals from coumarin moiety could contribute to the development of promising antifungal. Its resemblance and structural diversity make it possible to produce an auspicious antifungal candidate. Due to the natural origin of coumarin, its presence in diversity, and their broad spectrum of pharmacological activities, it secures an important place for the researcher to investigate and develop it as a promising antifungal in future. This manuscript discusses the bioavailability of coumarin (natural secondary metabolic molecule) that has privileged scaffold for many mycologists to develop it as a broad-spectrum antifungal against several opportunistic mycoses. As a result, several different kinds of coumarin derivatives were synthesized and their antifungal properties were evaluated. This review compiles various coumarin derivatives broadly investigated for antifungal activities to understand its current status and future therapeutic scope in antifungal therapy.

The Age of Coumarins in Plant-Microbe Interactions

Coumarins are a family of plant-derived secondary metabolites that are produced via the phenylpropanoid pathway. In the past decade, coumarins have emerged as iron-mobilizing compounds that are secreted by plant roots and aid in iron uptake from iron-deprived soils. Members of the coumarin family are found in many plant species. Besides their role in iron uptake, coumarins have been extensively studied for their potential to fight infections in both plants and animals. Coumarin activities range from antimicrobial and antiviral to anticoagulant and anticancer. In recent years, studies in the model plant species tobacco and Arabidopsis have significantly increased our understanding of coumarin biosynthesis, accumulation, secretion, chemical modification and their modes of action against plant pathogens. Here, we review current knowledge on coumarins in different plant species. We focus on simple coumarins and provide an overview on their biosynthesis and role in environmental stress responses, with special attention for the recently discovered semiochemical role of coumarins in aboveground and belowground plant-microbe interactions and the assembly of the root microbiome.

Synthesis of 4H,5H-pyrano[3,2-c][1]benzopyran-5-ones in aqueous media

The reaction of substituted cinnamonitriles with 4-hydroxycoumarin in water in the presence of triethylbenzyl-ammonium chloride affords 2-amino-4-aryl-4H,5H-pyrano [3,2-c] [1]benzopyran-5-one derivatives.

New Metabolites of Coumarin Detected in Human Urine Using Ultra Performance Liquid Chromatography/Quadrupole-Time-of-Flight Tandem Mass Spectrometry

Coumarin (1,2-benzopyrone) is a natural compound whose metabolism in humans was established in the 1970s. However, a new metabolite was recently identified in human plasma, indicating that the metabolism of coumarin has not been completely elucidated. To complement the knowledge of its metabolism, a rapid and sensitive method using UPLC-QTOF-MS was developed. A total of 12 metabolites was identified using MetaboLynxTM software, including eight metabolites not previously reported in human urine. The identified biotransformation included hydroxylation, glucuronidation, sulfation, methylation, and conjugation with N-acetylcysteine. The present work demonstrates that the metabolism study of coumarin was incomplete, possibly due to limitations of old techniques. The identification of eight inedited metabolites of such a simple molecule suggests that the information regarding the metabolism of other drugs may also be incomplete, and therefore, new investigations are necessary.

Screening of Fruits of Seven Plants Indicated for Medicinal Use in Iraq

Introduction:

Coumarins exert many biological effects in humans, animals, and plants, which make the evaluation of their biological activities and study of their role in ethnomedicine highly valued.

Objectives:

Here, we selected seven plants which have ethnopharmacological use as antimicrobial in Iraq and the aims were to quantify the two structural isomers bergapten and methoxsalen in their seeds, to evaluate the antibacterial activities against several clinical isolates, and to isolate bergapten and methoxsalen from Ammi majus.

Materials and Methods:

Seven plants were extracted by petroleum ether (PE) and ethanol (EtOH). Bergapten and methoxsalen were separated and purified by preparative thin-layer chromatography. Quantification of the furanocoumarins has been conducted by high-performance liquid chromatography, and all the plant extracts and pure compounds were checked for antibacterial activities utilizing alamar blue microplate assay.

Results:

Cuminum cyminum was deprived of bergapten and methoxsalen and methoxsalen was not detected from Apium graveolens. Bergapten was abundant in PE more than in EtOH; on the other hand, EtOH was rich in methoxsalen. The separation of the two structural isomers was performed using normal phase chromatography and ultraviolet light as an indicator. All extracts showed weak to moderate antibacterial activities against Gram-positive isolates which were more sensitive than the negative ones. C. cyminum extract was least active, uncover the antibacterial role of bergapten and methoxsalen.

Conclusion:

These findings support the medicinal use of seeds of seven plants from Apiaceae family and quantify the two pharmacologically important furanocoumarins (bergapten and methoxsalen).

SUMMARY

This study was conducted to evaluate the antibacterial activities of seven plants seeds used in local medicine in Iraq. High-performance liquid chromatography was used to quantify bergapten and xanthotoxin in non-polar and polar extracts of these seeds. This study supports the medicinal use of these plants and clarifies the role of bergapten and xanthotoxin in antibacterial activities of these plants.

Abbreviations used: EtOH: Ethanol; MIC: Minimum inhibitory concentration; PE: Petroleum ether; Rf: Retardation factor; Rt: Retention time.

Toxicity of coumarins synthesized by Pechmann-Duisberg condensation against Drosophila melanogaster larvae and antibacterial effects

On the background of the search of new insecticides friendly with the environment for replace those from synthesis organic origin with adverse effects on animals, soils and vegetables. It is reported in this study, the synthesis of a series of coumarins derivatives synthesized by Pechmann-Duisberg condensation assisted by microwave irradiation, their antibacterial and insecticidal activities. The most relevant results show that all compounds exhibit a mortality effect of 30-80% with doses between 10 and 100 μg/mL. This activity is related to alkyl or aryl substituent type at position C-4 coumarin skeleton. The coumarins 5, 6, 7 and 9 showed highest insecticidal activities, and these coumarins have at 4-position a bulky and low polarity substituent. The aim of this work is to find the effects of the 4-substitued coumarins with different lipophilic and bulky substituents. Even though many researchers were worked on coumarins, there are not reports about the insecticidal effects of specifically 4-substitued coumarins. The difference of our major findings versus current knowledge is in this scope of the research. On the other hand, was possible to find that a chloride at 4-position, drew to extend the antibacterial spectra.

Qualitative and quantitative determination of coumarin using surface-enhanced Raman spectroscopy coupled with intelligent multivariate analysis

Coumarin is harmful to health but still used in cosmetics, tobacco, or illegally added into food as a spice in trace amounts so that it is exceedingly difficult to be determined accurately.

Antifouling activity of green-synthesized 7-hydroxy-4-methylcoumarin

In the search for new environmental-friendly antifoulants for replace metallic biocides, 7-hydroxy-4-methylcoumarin was synthesized according to green chemistry procedures. This compound was characterized by current organic analysis and its antifouling properties were firstly evaluated on the bivalve Mytilus edulis platensis in the laboratory. In the second stage, a soluble matrix antifouling coating formulated with this compound was assayed in marine environment. Laboratory experiments showed that 7-hydroxy-4-methylcoumarin was effective in inhibiting both the settlement as well as the byssogenesis of mussels. In addition, after exposure time in the sea, painted panels containing this compound showed strong antifouling effect on conspicuous species of the fouling community of Mar el Plata harbor. In conclusion, green-synthesized coumarin could be a suitable antifoulant candidate for marine protective coatings.

Facile and eco-friendly synthesis of chromeno[4,3-b]pyrrol-4(1H)-one derivatives applying magnetically recoverable nano crystalline CuFe2O4 involving a domino three-component reaction in aqueous media

Nanocrystalline CuFe₂O₄ catalyzed one pot three component synthesis of chromeno[4,3-b]pyrrol-4(1H)-one derivatives has been achieved in aqueous media.

Recent progress in the drug development of coumarin derivatives as potent antituberculosis agents

Tuberculosis (TB) is still a challenging worldwide health problem and mycobacterium tuberculosis (MTB) remains one of the most deadly human pathogens. TB is the second leading infectious cause of mortality today behind only HIV/AIDS. The impetus for developing new structural classes of antituberculosis drugs comes from the emergence of multi-drug resistant (MDR) strains. The development of MDR strains to commonly used drugs is due to, longer durations of therapy as results of resistance, and the resurgence of the disease in immune compromised patients. Therefore, there is an urgent need to explore new antitubercular (anti-TB) agents. Ironically, the low number of potentially new chemical entities which can act as anti-TB candidates is of great importance at present situation. Considering the severity of the problem, WHO has prepared a strategic plan in Berlin declaration 2007 to stop TB, globally. Among the oxygen heterocycles, coumarin derivatives are important motifs, which can be widely found in many natural products, and many of them displaying diverse biological activities. This spectacular spectrum of applications has intrigued organic and medicinal chemists for decades to explore the natural coumarins or their synthetic analogs for their applicability as anti-TB drugs. To pave the way for the future research, there is a need to collect the latest information in this promising area. In the present review, we collated published reports on coumarin derivatives to shed light on the insights on different types of methods reported for their preparations, characterizations and anti-TB applications, so that its full therapeutic potential class of compounds can be utilized for the treatment of tuberculosis. Therefore, the objective of this review is to focus on important coumarin analogs with anti-TB activities, and structure-activity relationships (SAR) for designing the better anti-TB agents. It is hoped that, this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic coumarin-based anti-TB drugs.

Synthesis of indeno and acenaphtho cores containing dihydroxy indolone, pyrrole, coumarin and uracil fused heterocyclic motifs under sustainable conditions exploring the catalytic role of the SnO2 quantum dot

A tin oxide (SnO₂) quantum dot (QD) catalyzed approach for the synthesis of indeno and acenaphtho cores containing dihydroxy indolone, pyrrole, coumarin and uracil fused derivatives was achieved via multicomponent one-pot approach in aqueous medium.

A rapid and modified approach for C-7 amination and amidation of 4-methyl-7-nonafluorobutylsulfonyloxy coumarins under microwave irradiation

A rapid approach for the synthesis of an array of 4-methyl-7-substituted coumarins has been developed.

4-(2-Bromo-phen-yl)-2-phenyl-pyrano[3,2-c]chromen-5(4H)-one

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

Toxicity of coumarin and various methyl derivatives in cultures of rat hepatocytes and V79 cells

The toxicity of coumarin and various simple methyl derivatives in rat hepatocyte and V79 cell cultures was studied to investigate further the mechanism of coumarin hepatotoxicity. Coumarin was six times more toxic in hepatocyte cultures from phenobarbitone (PB)-treated rats than in those from untreated rats. At concentrations below 3 mm, coumarin did not affect the survival of V79 lung fibroblasts. SKF-525A inhibited coumarin-induced toxicity in hepatocytes cultured from PB-treated rats, whereas depletion of hepatocyte glutathione (GSH) levels with buthionine sulphoximine (BSO) significantly increased toxicity. Dihydrocoumarin (DHC) had little effect on the survival of cultured hepatocytes, indicating that the 3,4-double bond is an important determinant of coumarin toxicity. In general, the toxicity of coumarin in hepatocyte cultures was reduced by substitution with one or more methyl groups. 3-Methylcoumarin (MeC), however, was more toxic than coumarin itself in hepatocyte cultures from untreated rats. Except for 3,4-diMeC, the methyl derivatives were markedly more toxic in rat hepatocytes than in V79 cell cultures. The data obtained for coumarin and 4-MeC, and possibly 6-MeC and 7-MeC, are consistent with hepatocyte toxicity being due to the cytochrome P-450-dependent formation of one or more toxic metabolites that may be detoxified by reacting with GSH. This was less apparent for 3-MeC and 3,4-diMeC, although depletion of GSH levels significantly increased the hepatocyte toxicity of both compounds.