Anti-HIV coumarins from Calophyllum seed oil

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.

Heteroaromatization of Coumarin Part I: Design, Synthesis, Reactions, Antitumor Activities of Novel Pyridine and Naphthyridine Derivatives

INTRODUCTION

A novel series of chromen-3-yl-pyridine moieties were synthesized. IR, NMR, and MS spectroscopy were used to confirm the structure of these novel compounds and study antitumor activity of these compounds. The structure-activity relationship investigation demonstrated that 2,4-diamino- 5-(3-methoxyphenyl)-7-(2-oxo-2H-chromen-3-yl)-1,8-naphthyridine-3-carbonitrile (16), naphthyridine- 3-carbonitrile derivatives 17, 18 and pyrido[2,3-d]pyrimidine derivative 12 were found to be more effective, while compounds 5a,b, 9c, 11, 13 and 14 showed moderate activity for antitumor activities.

OBJECTIVES

The objective was to design a series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives and study the antitumor of these compounds.

MATERIALS AND METHODS

The condensation reaction of 3-acetyl-2H-chromen-2-one with 3-methoxy benzaldehyde and malononitrile or ethyl cyanoacetate in the presence of ammonium acetate and acetic acid under reflux to give the corresponding chromen-3-yl pyridine-3-carbonitrile derivatives.

RESULTS

In this study, the antitumor activity of the synthesized compounds chromen-3-yl-pyridine derivatives has been determined for the broad spectrum of cytotoxic activity toward the investigated three cell lines and 5-Fluorouracil, as reference drugs.

CONCLUSION

A series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives were synthesized in this work. All compounds were evaluated for cytotoxic activity.

A new chromanone acid derivative from the nut oil resin of Calophyllum inophyllum

One novel chromanone acid derivative, namely inocalophylline C (1), together with one known compound calophyllolide (2), were isolated from the methanolic extract of nut oil resin of Calophyllum inophyllum L., a medicinal plant widely distributed in Vietnam. The isolated compound structures were elucidated by spectroscopic methods and the absolute configuration of 1 was established by the single-crystal X-ray crystallography as ethyl (R) 3-((2 R,3R,6R)-4-hydroxy-2,3-dimethyl-6-((R)-5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl)-6-(3-methylbut-2-en-1-yl)-5,7-dioxo-3,5,6,7-tetrahydro-2H-chromen-8-yl)-3-phenylpropanoate.

The complete chloroplast genome of Calophyllum soulattri Burm. f. (Calophyllaceae)

Calophyllum soulattri Burm. f. (1768) is an evergreen tree native to Southeast Asia, Australia, and the Solomon Islands. It is known for its medicinal uses and has been utilized in traditional folk medicine. However, genomic resources for this species are still unavailable. In this study, we sequenced and assembled the first complete chloroplast genome of C. soulattri using next-generation sequencing data. The chloroplast genome of C. soulattri is 161,381 bp in length with a total GC content of 36.36%. The chloroplast genome contains a large single copy (LSC) region of 88,680 bp, a small single copy (SSC) region of 17,453 bp, and two inverted repeat (IR) regions of 27,624 bp each. Furthermore, the chloroplast genome has 131 genes, which include 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis indicated that C. soulattri is clustered in the same branch with C. inophyllum and is closely related to Mesua ferrea.

Phosphine-Mediated [3+2] Cyclization for the Synthesis of Coumarin-Based CF3-Containing Furanones

A tertiary phosphine-mediated [3+2] cyclization reaction of ynones with fluorinated coumarin derivatives has been developed to give a series of coumarin-based CF3-containing furanones in moderate to good yields under mild reaction conditions. Preliminary investigation into their antitumor activities is also presented.

Formulation and Biomedical Activity of Oil-in-Water Nanoemulsion Combining Tinospora smilacina Water Extract and Calophyllum inophyllum Seeds Oil

Introduction

Tinospora smilacina is a native plant used in traditional medicine by First Nations peoples in Australia to treat inflammation. In our previous study, an optimised Calophyllum inophyllum seed oil (CSO) nanoemulsion (NE) showed improved biomedical activities such as antimicrobial, antioxidant activity, cell viability and in vitro wound healing efficacy compared to CSO.

Methods

In this study, a stable NE formulation combining T. smilacina water extract (TSWE) and CSO in a nanoemulsion (CTNE) was prepared to integrate the bioactive compounds in both native plants and improve wound healing efficacy. D-optimal mixture design was used to optimise the physicochemical characteristics of the CTNE, including droplet size and polydispersity index (PDI). Cell viability and in vitro wound healing studies were done in the presence of CTNE, TSWE and CSO against a clone of baby hamster kidney fibroblasts (BHK-21 cell clone BSR-T7/5).

Results

The optimised CTNE had a 24 ± 5 nm particle size and 0.21± 0.02 PDI value and was stable after four weeks each at 4 °C and room temperature. According to the results, incorporating TSWE into CTNE improved its antioxidant activity, cell viability, and ability to promote wound healing. The study also revealed that TSWE has >6% higher antioxidant activity than CSO. While CTNE did not significantly impact mammalian cell viability, it exhibited wound-healing properties in the BSR cell line during in vitro testing. These findings suggest that adding TSWE may enhance CTNE's potential as a wound-healing treatment.

Conclusion

This is the first study demonstrating NE formulation in which two different plant extracts were used in the aqueous and oil phases with improved biomedical activities.

Protective Effect of 3-Benzoyl-7-Hydroxy Coumarin on Lipid Peroxidation and Minerals on Rat Liver Tissues Induced Oxidative Stress with Lead Acetate

Lead is a toxic substance and damages human metabolism. Coumarin-derived substances have many effects such as antioxidant, anticancer, and antibacterial ones. In this study, the effects of 3-benzoyl-7-hydroxy coumarin on rat liver tissues under oxidative stress with lead acetate were investigated. In the study, rats were divided into 4 groups. Control group (K), Coumarin group (KUM), Lead acetate group (P) and Coumarin+Lead acetate group (KUMP) groups were formed. Malondialdehyde (MDA), lead (Pb), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) levels were determined in the liver tissues of the rats. MDA level of P group increased compared to the other groups. A decrease was observed in the KUMP group compared to the P group MDA level. While the Pb and Fe levels of the P group increased compared to the K group, the Pb and Fe levels of the KUMP group decreased compared to the P group. As a result, it is concluded that the 3-benzoyl-7-hydroxy coumarin molecule protects the high lipid peroxidation, lead, and iron metabolism caused by lead acetate in the liver.

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.

Optimisation of Calophyllum inophyllum seed oil nanoemulsion as a potential wound healing agent

Background

Efficient delivery systems of Calophyllum inophyllum seed oil (CSO) in the form of nanoemulsion were optimised to enhance its stability and ensure its therapeutic efficiency as a potential agent for various biomedical applications.

Method

Response Surface Methodology (RSM) was used to determine the effects of independent variables (oil, surfactant, water percentage and homogenisation time) on physicochemical characteristics, including droplet size, polydispersity index and turbidity.

Results

The optimised CSO nanoemulsion (CSONE) has a 46.68 nm particle size, 0.15 Polydispersity index value and 1.16 turbidity. After 4 weeks of storage at 5 ± 1 °C and 25 ± 1 °C, the CSONE was physically stable. The optimised CSO nanoemulsion showed enhancement in cell viability and wound healing in baby hamster kidney a clone BHK-21 (BSR) cells as compared to the CSO. The wound healing property of CSONE was higher than CSO.

Conclusion

Thus, our in vitro wound healing results demonstrated that CSO in the nanoemulsion form can promote wound healing by enhancing the proliferation and migration of epidermal cells.

Graphical Abstract

The coarse emulsion of Calophyllum inophyllum seed oil nano emulsion was prepared using high shear homogeniser techniques. The optimised CSONE with the droplet size of 46.68 nm was prepared from a mixture of CSO, Tween 80, and high pure water (HPW), then used for the biological investigation. The in vitro cell monolayer scratch assay revealed that CSONE in the lowest concentration of CSO resulted in 100% wound closure after 48 hrs. The optimised CSO nanoemulsion was found to be a promising and effective approach in the treatment of wounds by boosting the proliferation and migration of epidermal cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03751-6.

Antimicrobial Secondary Metabolites from the Mangrove Plants of Asia and the Pacific

Microbes such as the White Spot Syndrome Virus account for severe losses in the shrimp farming industry globally. This review examines the literature on the mangrove plants of Asia and the Pacific with antibacterial, antifungal, or antiviral activities. All of the available data published on this subject were collected from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and a library search from 1968 to 2022. Out of about 286 plant species, 119 exhibited antimicrobial effects, and a total of 114 antimicrobial natural products have been identified including 12 with MIC values below 1 µg/mL. Most of these plants are medicinal. The mangrove plants of Asia and the Pacific yield secondary metabolites with the potential to mitigate infectious diseases in shrimp aquaculture.

Design and Synthesis of Coumarin Derivatives as Cytotoxic Agents through PI3K/AKT Signaling Pathway Inhibition in HL60 and HepG2 Cancer Cells

In this study, a series of coumarin derivatives, either alone or as hybrids with cinnamic acid, were synthesized and evaluated for their cytotoxicity against a panel of cancer cells using the MTT assay. Then, the most active compounds were inspected for their mechanism of cytotoxicity by cell-cycle analysis, RT-PCR, DNA fragmentation, and Western blotting techniques. Cytotoxic results showed that compound (4) had a significant cytotoxic effect against HL60 cells (IC₅₀ = 8.09 µM), while compound (8b) had a noticeable activity against HepG2 cells (IC₅₀ = 13.14 µM). Compounds (4) and (8b) mediated their cytotoxicity via PI3K/AKT pathway inhibition. These results were assured by molecular docking studies. These results support further exploratory research focusing on the therapeutic activity of coumarin derivatives as cytotoxic agents.

Novel 3-phenyl-1- (alkylphenyl)-9-oxa-4-azaphenanthren-10-ones as inhibitors of some enzymes: synthesis, characterization, biological evaluation and molecular docking studies

A series of novel 3-phenyl-1-(alkylphenyl)-9-oxa-4-azaphenanthren-10-ones and (E)-1-phenyl-3-(aryl)prop-2-en-1-ones were synthesized and characterized by IR, 1H NMR, 13C spectroscopy and elemental analysis. The synthesized Compounds 5a-f were subjected to molecular docking simulation with three proteins, namely, tyrosyl-tRNA synthetase, heme oxygenase 1 and acetylcholinesterase to evaluate the antibacterial, antioxidant and acetylcholinesterase inhibition, respectively. Moreover, the docked poses of all compounds inside the proteins were subjected to further dynamic simulation through the calculation of the binding free energy using MM-GBSA analysis. Compound 5d exhibits high potential inhibition against antibacterial, antioxidant and acetylcholinesterase activities. Compounds 3d, 3f, 5a and 5d recorded an important scavenging activity in DPPH and ABTS assays. Investigation of the anti-acetylcholinesterase activity of the synthesized compounds showed that Compounds 5a and 3d are the most potent inhibitors against AchE, with percent inhibition values of 38 and 30%, respectively.Communicated by Ramaswamy H. Sarma.

Daphnetin, a Coumarin in Genus Stellera Chamaejasme Linn: Chemistry, Bioactivity and Therapeutic Potential

Coumarins is a huge family of phenolic compounds containing a common structure of 2 H -1-benzopyran-2-one. Nowadays, more than 1,300 natural-based coumarins have been identified in a variety of plants, bacteria and fungi, many of them exhibited promising biomedical performance. Daphnetin (7,8-dihydroxycoumarin) is a typical coumarin associated with a couple of bioactivities such as anti-cancer, antibacterial, anti-inflammatory and anti-arthritis. In the treatment of diseases, it has been verified that daphnetin has outstanding therapeutic effects on diabetes, arthritis, transplant rejection, cancer and even on central nervous system diseases. Herein, we summarized the chemical synthetic methodologies, bioactivities, therapeutic potentials and structure-activity relationships of daphnetin and its derivatives. Hopefully, this review would be beneficial for the discovery of new coumarin-based biomedicine in the near future.

Natural Coumarins: Exploring the Pharmacological Complexity and Underlying Molecular Mechanisms

Coumarins belong to the benzopyrone family commonly found in many medicinal plants. Natural coumarins demonstrated a wide spectrum of pharmacological activities, including anti-inflammatory, anticoagulant, anticancer, antibacterial, antimalarial, casein kinase-2 (CK2) inhibitory, antifungal, antiviral, Alzheimer's disease inhibition, neuroprotective, anticonvulsant, phytoalexins, ulcerogenic, and antihypertensive. There are very few studies on the bioavailability of coumarins; therefore, further investigations are necessitated to study the bioavailability of different coumarins which already showed good biological activities in previous studies. On the evidence of varied pharmacological properties, the present work presents an overall review of the derivation, availability, and biological capacities of coumarins with further consideration of the essential mode of their therapeutic actions. In conclusion, a wide variety of coumarins are available, and their pharmacological activities are of current interest thanks to their synthetic accessibility and riches in medicinal plants. Coumarins perform the valuable function as therapeutic agents in a range of medical fields.

Synthesis and anticancer evaluation of some coumarin and azacoumarin derivatives

Coumarin and its nitrogen analogue 1-aza coumarin are a class of lactones and lactams, respectively, which are indispensable heterocyclic units to both chemists and biochemists. 1-Aza coumarin derivatives, which ultimately metabolize as the corresponding 8-hydroxy coumarins in the biological system are therefore found to be very good anti-inflammatory, anti-cancer, and analgesic agents. A series of hybrid substituted coumarin and azacoumarin-3-carboxylic acid derivatives (8-methoxycoumarin-3-carboxylic acid (4a), 8-methoxyazacoumarin-3-carboxylic acid (4b), 5-bromo-8-methoxycoumarin-3-carboxylic acid (5a), 5-bromo-8-methoxyazacoumarin-3-carboxylic acid (5b), 2-acetoxy-5-bromo-8-methoxyquinoline-3-carboxylic acid (6), and 5,7-di(phenylazo)-8-methoxycoumarin-3-carboxylic acid (7) were synthesized and structurally proved using spectral and elemental analysis data. Substituted coumarin-3-carboxylic acid (4a and 5a) and Substituted azacoumarin-3-carboxylic acid (4b, 5b and 6) were tested for their in vitro cytotoxic activity against MCF-7 and HepG-2 cell lines.

The Rich Legacy and Bright Future of Transition-Metal Catalyzed Peroxide Based Radical Reactions

This personal account is mainly focused on the author's involvement in the field of transition metal-catalyzed peroxide based radical reactions. Over the past decades, radical chemistry has flourished and become crucial in contemporary synthetic organic chemistry. Owing to the presence of a single electron in one orbital, radicals are very unstable and react very fast. To carry out desired transformations and to control the side reactions the stabilizations of these radicals is essential. Fortunately, the implementation of a suitable transition metal and peroxide combination into the radical reactions have proved beneficial. Transition metals not only stabilizes the radicals but also protects them from being quenched by undesired homo-coupling or fragmentation. Transition metal-catalyzed radical-radical reactions provide an innovative way for the construction and derivatization of carbocycles and heterocycles. The objective of this review is to give an overview of the construction and derivatization of heterocycles through the lens of radical chemistry, mainly focusing on research work done by our group.

Coumarin-1,2,3-triazole Hybrid Molecules: An Emerging Scaffold for Combating Drug Resistance

Undoubtedly, antibiotics have saved billions of lives, but lack of novel antibiotics, development of resistance mechanisms in almost all clinical isolates of bacteria, and recurrent infections caused by persistent bacteria hamper the successful treatment of the infections. Due to the widespread emergence of resistance, even the new families of anti-microbial agents have a short life expectancy. Drugs acting on a single target often lead to drug resistance and are associated with various side effects. For overcoming this problem, either multidrug therapy, or a single drug acting on multiple targets may be used. The latter is called 'hybrid molecules,' which are formed by clubbing two biologically active pharmacophores together, with or without an appropriate linker. In this rapidly evolving era, the development of natural product-based hybrid molecules may be a super-alternative to multidrug therapy, for combating drug resistance caused by various bacterial and fungal strains. Coumarins (benzopyran-2-one) are one of the earliest reported plant secondary metabolites having a clinically proven diverse range of pharmacological properties. On the other hand, 1,2,3-triazole is a common pharmacophore in many drugs responsible for polar interactions, improving the solubility and binding affinity to biomolecular targets. In this review, we discuss recent advances in Coumarin-1,2,3-triazole hybrids as potential anti-bacterial agents, aiming to provide a useful platform for the exploration of new leads with a broader spectrum, more effectiveness and less toxicity with multiple modes of action for the development of cost-effective and safer drugs in the future.

Visible-Light-Induced Direct Csp2-H Radical Trifluoroethylation of Coumarins with 1,1,1-Trifluoro-2-iodoethane (CF3CH2I)

Herein, we developed the first visible-light-induced direct Csp²-H radical 2,2,2-trifluoroethylation of coumarins with commercially available and cheap reagent CF₃CH₂I at room temperature. This transformation proceeded smoothly under mild conditions and showed excellent functional group compatibility. The synthetic value of the protocol was also demonstrated by the successful functionalization of several pharmaceuticals.

Improving the Antioxidant Properties of Calophyllum inophyllum Seed Oil from French Polynesia: Development and Biological Applications of Resinous Ethanol-Soluble Extracts

Tamanu oil from Calophyllum inophyllum L. has long been used in traditional medicine. Ethanol extraction was found the best strategy for recovering bioactive compounds from the resin part of Tamanu oil, yielding two neutral and acidic resins fractions with high phenolics, flavonoids and pyranocoumarins concentrations. A further cascade of LPLC/HPLC separations of neutral and acidic resin fractions allowed identifying fifteen metabolites, and among them, calanolide D and 12-oxocalanolide A (both in neutral fraction) were first identified from a natural source. All these extracts, subfractions and isolated metabolites demonstrated increased free radical scavenging, antioxidant, anti-inflammatory, antimicrobial and antimycobacterial activity compared to Tamanu oil and its de-resinated lipid phase. Overall, these results could promote resinous ethanol-soluble Tamanu oil extracts as a useful multifaceted and renewable medicinal resource.

4-Aminocoumarin derivatives: synthesis and applications

4-Aminocoumarins represent an important class of a versatile scaffold in organic synthesis and have been consistently used as a building block in organic chemistry for the synthesis of different heterocyclic compounds.

UV-Protection Performance of Calophyllum inophyllum Seed Extracts: A Natural Ultraviolet Screening Agent

Demand for sunscreen products has been rising in recent years due to increasing cases of skin damage caused byultraviolet radiation (UVR). Recent studies have proved that some materials in commercial sunscreen products are harmful to the marine ecosystem. Therefore, the development of a photoprotective and environmentally friendly screening agent has been a leading direction for the cosmetic industry. Calophyllum inophyllum is a seaside plant found in the Pacific Rim, regarded as a potential source of biodiesel feedstock given the high oil content of its seeds. Due to the harsh environment of its natural habitat, C. inophyllum has developed UV-absorbing secondary metabolites, which are natural sources for screening agents. In this study, samples of seed extracts of C. inophyllum were subjected to in vitro UV, Fourier-transform infrared (FTIR) spectroscopy, and cytotoxicity analysis; all the samples extracted by solvents of various polarities showed different chemical compositions by FTIR spectroscopy and levels of cytotoxicity. The n-hexane seed extract showed the highest UVA and UVB absorption efficiencies. In the in vitro cytotoxicity test on human skin fibroblast cells, seed oil of C. inophyllum demonstrated low cytotoxicity. Results have shown that seed extracts of C. inophyllum can be an ideal material for a natural high-efficiency screening agent.

Naturally Occurring Calanolides: Occurrence, Biosynthesis, and Pharmacological Properties Including Therapeutic Potential

Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological aspects including mechanism of action and structure activity relationships, pharmacokinetics, therapeutic potentials and available patents.

Expeditious and eco-friendly synthesis of new multifunctionalized pyrrole derivatives and evaluation of their antioxidant property

Diminution of oxidative stress-mediated diseases is an essential pharmaceutical objective in modern biomedical research. The present work stresses upon the efficient and eco-friendly synthesis of an array of novel diversely functionalized pyrrole derivatives which are found to be antioxidants with reactive oxygen species (ROS) shielding competency against the deleterious consequence of oxidative stress. The results of the investigation displayed the effect of structural modification of the pyrrole derivatives on their respective antioxidant properties to various ROS. Noteworthy, the pyrrole moiety bearing 4-hydroxycoumarin or 2-hydroxy-1,4-naphthoquinone as substituent showed outstanding defensive potency towards OH and O₂^- while, nitrogen atom linked with aliphatic side-chain in the pyrrole scaffold made a strong affirmative impression in DPPH scavenging assay. More interestingly, an influencing reducing power was observed in pyrrole derivatives carrying cyclohexane 1,3-dione as one of the substituents. To have a comprehensive acuteness into the antioxidant capacity of the synthesized pyrrole derivatives against Trolox as a standard antioxidant, a crucial approach was taken into account by calculating TEAC (Trolox Equivalent Antioxidant Capacity) in case of OH and DPPH scavenging activity.

Fe3O4@C@OSO3H as an efficient, recyclable magnetic nanocatalyst in Pechmann condensation: green synthesis, characterization, and theoretical study

Novel sulfonated carbon-coated magnetic nanoparticles (SCCMNPs; Fe₃O₄@C@OSO₃H) were designed, synthesized, characterized, and applied as an efficient nanocatalyst for green synthesis of coumarin derivatives through Pechmann condensation. The Fe₃O₄@C@OSO₃H was manufactured through a simple and inexpensive two-step procedure and characterized by FTIR, EDX, XRD, SEM, TEM, DLS, VSM, and TGA techniques. It was identified as an efficient heterogeneous catalyst in the Pechmann condensation of phenol derivatives and β-ketoesters, leading to high-yield coumarin derivatives under solvent-free conditions. The Fe₃O₄@C@OSO₃H removed after reaction finishing point by an external magnet, and it was reused fifteen times at the same conditions. Besides, theoretical studies were carried out using B3LYP/6-311++G(d,p) to more consideration of the reaction mechanism. The study of the frontier molecular orbitals, NBO atomic charges, molecular electrostatic potential of reactants, as well as Pechmann condensation mechanism was known very useful in suitable reactant choice. The reaction was performed through the electrophilic attack, dehydration, and trans-esterification, respectively.

Recurrent π–π stacking motifs in three new 4,5-dihydropyrazolyl–thiazole–coumarin hybrids: X-ray characterization, Hirshfeld surface analysis and DFT calculations

Two different π–π stacking modes are described, studied and characterized in the crystal structures of 4,5-dihydropyrazolyl–thiazole–coumarin hybrids, including a partial aliphatic ring.

In(OTf)3-catalysed easy access to dihydropyranocoumarin and dihydropyranochromone derivatives

Allylation/cyclization of β-ketolactone-type heterocyclic compounds, under In(OTf)₃-catalysis, for the construction of biologically active dihydropyranocoumarin and dihydropyranochromone derivatives.

Structural, spectroscopic and first-principles studies of new aminocoumarin derivatives

The new aminocoumarin derivatives 3-[1-(3-hydroxyanilino)ethylidene]-3H-chromene-2,4-dione, (1), 3-[1-(4-hydroxyanilino)ethylidene]-3H-chromene-2,4-dione, (2), and 3-[1-(2-hydroxyanilino)ethylidene]-3H-chromene-2,4-dione, (3), all C₁₇H₁₃NO₄, were synthesized by reacting an equimolar amount of 3-acetyl-4-hydroxycoumarin and the corresponding aminophenol in absolute ethanol. Structural and spectroscopic analysis of these phases revealed that derivatives (1) and (2) are isomers of previously reported (3) [Brahmia et al. (2013). Acta Cryst. E69, o1296]. The crystal structures of meta derivative (1) and para derivative (2) were ab initio determined from powder X-ray diffraction data using the direct-space approach. Both (1) and (2) adopt the orthorhombic space group P2₁2₁2₁. These isomers show hydrogen bonds and rich π-π stacking, together with π...H interactions, which are built by conjugated systems of coumarin and phenol rings. In the crystalline lattice, the packing of (1) and (3) are mainly stabilized through O-H...O hydrogen bonding between neighbouring coumarin molecules, while hydrogen bonds between coumarin and water molecules build the stable crystal structure of derivative (2). A big similarity in the skeletons of the IR spectra of these isomers was noticed. Derivative (2) exhibits two weak bands which were not present in the spectra of the other two derivatives, at 2370 and 2948 cm^-1, which can be assigned to the O-H vibrations of the solvent (H₂O) trapped in the structure of (2). These aminocoumarin derivatives display absorption maxima in the visible region, attributed to π-π delocalization involving the whole electronic system of the compounds with a considerable charge-transfer character originating from the aminophenyl ring and pointing towards the coumarin system which is characterized by a high electron-accepting character. Additionally, the isolated molecular ground-state geometries were optimized at the PBE0/TZP level and the electronic properties, molecular electrostatic potential and Hirshfeld charges were determined.

Isolates from Monechma ciliatum seeds' extract hampered Porphyromonas gingivalis hemagglutinins

Porphyromonas gingivalis is a major periodontitis pathogen that produces several virulence factors including hemagglutinins. These proteins, which are vital molecules, allow P. gingivalis to uptake iron and heme by attaching, aggregating, and lysing erythrocytes. In this study, we evaluated the inhibitory activity of the aqueous extract of Monechma ciliatum seeds against the hemagglutination activity of P. gingivalis. M. ciliatum is a Sudanese medicinal herb that grows in arid and semi-arid lands of tropical Africa. The water extracted from dry powdered seeds was partitioned using ethyl acetate followed by reversed-phase chromatography, thin-layer chromatography, ESI-MS, and NMR analysis resulting in the isolation of four compounds identified as oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol with MICs of 15-100 μg/ml against hemagglutination. We believe that the isolation and purification of these compounds will expand the application of M. ciliatum as a natural therapeutic or preventative agent. PRACTICAL APPLICATIONS: Monechma ciliatum or black mahlab is a famous medicinal plant that grows in some parts of arid and semi-arid areas of tropical Africa including western Sudan. Despite its nutritional and traditional medical applications, no studies have evaluated its anti-hemagglutination activity against periodontal pathogens. In this study, four active compounds (oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol) were isolated and identified from an aqueous extract of M. ciliatum seeds. The isolated compounds revealed high levels of inhibitory activity against all hemagglutinin agents secreted by Porphyromonas gingivalis. This evidence of inhibitory activity will encourage the application of M. ciliatum effectively as a functional food or therapeutic agent to prevent periodontal diseases in the early stages.

Rational approaches, design strategies, structure activity relationship and mechanistic insights for therapeutic coumarin hybrids

Hybrid molecules, furnished by combining two or more pharmacophores is an emerging concept in the field of medicinal chemistry and drug discovery that has attracted substantial traction in the past few years. Naturally occurring scaffolds such as coumarins display a wide spectrum of pharmacological activities including anticancer, antibiotic, antidiabetic and others, by acting on multiple targets. In this view, various coumarin-based hybrids possessing diverse medicinal attributes were synthesized in the last five years by conjugating coumarin moiety with other therapeutic pharmacophores. The current review summarizes the recent development (2014 and onwards) of these pharmacologically active coumarin hybrids and demonstrates rationale behind their design, structure-activity relationships (SAR) and mechanistic studies performed on these hybrid molecules. This review will be beneficial for medicinal chemist and chemical biologist, and in general to the drug discovery community and will facilitate the synthesis and development of novel, potent coumarin hybrid molecules serving as lead molecules for the treatment of complex disorders.

Click chemistry based regioselective one-pot synthesis of coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones as newer potent antitubercular agents

Coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones (8k-z) were synthesized via copper(I)-catalyzed azide-alkyne cycloaddition click chemistry. The synthesized hybrid molecules were characterized by spectral studies. Compounds 8k-z were screened for their in vitro anti-TB activity by using the Microplate Alamar Blue assay and for cytotoxicity using the MTT assay. Some of the compounds were found to be most potent against the tested Mycobacterium tuberculosis H37Rv strain with a MIC of 1.60 µg/ml. Further, docking the compounds into the InhA binding pocket showed strong binding interactions and effective overall docking scores were recorded. The drug-likeness and toxicity studies were computed using Molinspiration and Protox, respectively.

Alcohol Participates in the Synthesis of Functionalized Coumarin-Fused Pyrazolo[3,4-b]Pyridine from a One-Pot Three-Component Reaction

A concise and efficient approach to synthesizing coumarin-fused pyrazolo[3,4-b]pyridine via silica sulfuric acid (SSA) catalyzed three-component domino reaction under microwave irradiation has been demonstrated. Participation of various alcohols in construction of coumarin derivatives has been described for the first time. Short reaction time, high yields, one-pot procedure, usage of eco-friendly catalyst, and solvent are the key features of this method.