Natural Coumarin Research Articles

Structural mechanism of TRPV3 channel inhibition by the plant-derived coumarin osthole.

TRPV3, a representative of the vanilloid subfamily of TRP channels, is predominantly expressed in skin keratinocytes and has been implicated in cutaneous sensation and associated with numerous skin pathologies and cancers. TRPV3 is inhibited by the natural coumarin derivative osthole, an active ingredient of Cnidium monnieri, which has been used in traditional Chinese medicine for the treatment of a variety of human diseases. However, the structural basis of channel inhibition by osthole has remained elusive. Here we present cryo-EM structures of TRPV3 in complex with osthole, revealing two types of osthole binding sites in the transmembrane region of TRPV3 that coincide with the binding sites of agonist 2-APB. Osthole binding converts the channel pore into a previously unidentified conformation with a widely open selectivity filter and closed intracellular gate. Our structures provide insight into competitive inhibition of TRPV3 by osthole and can serve as a template for the design of osthole chemistry-inspired drugs targeting TRPV3-associated diseases.

7-geranyloxycoumarin enhanced radiotherapy effects on human gastric adenocarcinoma cells.

Gastric adenocarcinoma (GA) is a serious malignancy with growing incidence and mortality rate worldwide. The objective of the present study was to determine whether 7-geranyloxycoumarin, a natural monoterpene coumarin, could induce anticancer effects, in single use and/or in combination with anticancer drugs and ionizing radiation, on GA cells. 7-geranyloxycoumarin was synthesized by a reaction between 7-hydroxycoumarin and transgeranyl bromide. MKN45 cells were treated with 7-geranyloxycoumarin, and the viability of cells was determined by resazurin. Apoptosis was then evaluated by flow cytometric analysis using annexin V and propidium iodide, and the expression of P53 and BCL2 was analyzed by quantitative polymerase chain reaction (qPCR). Combinatorial effects of 7-geranyloxycoumarin with 5-fluorouracil (5-FU), cisplatin (CDDP), and X radiation were also evaluated. Assessment of cell viability indicated that 7-geranyloxycoumarin induced its toxic effects in a time- and dose-dependent manner. This was confirmed by the detection of apoptotic cells, and qPCR results revealed a significant downregulation in BCL2 expression. Although combinatorial use of 7-geranyloxycoumarin + 5-FU or + CDDP did not improve cytotoxicity of anticancer drugs, significant increase in the effectiveness of applied radiations was detected upon pretreatment with 7-geranyloxycoumarin. Our findings provide valuable insights into single and combinatorial effects of 7-geranyloxycoumarin on the GA cells.

Oxidative Coupling of Coumarins by Blue‐LED‐Driven in situ Activation of Horseradish Peroxidase in a Two‐Liquid‐Phase System

AbstractA blue‐LED‐driven two‐liquid‐phase system has been set up for the in situ activation of horseradish peroxidase avoiding the use of hydrogen peroxide and drawbacks related to enzyme denaturation and undesired radical side‐reactions. The photobiocatalytic system was applied for the oxidative coupling of natural and synthetic coumarins to bicoumarins, allowing to obtain homodimers in only one step, avoiding the use of tedious protecting groups. Two natural C‐2 symmetric bicoumarins derived from the coupling of scopoletin were synthesized for the first time. UV‐visible spectrophotometry analysis confirmed the radical‐free and blue‐LED‐driven in situ oxidation of the green solvent 2‐methyltetrahydrofuran to the corresponding hydroperoxide, which in turn oxidizes the ferric heme of horseradish peroxidase to ferryl intermediate, triggering the oxidative coupling reaction.

The Genus Haplophyllum Juss.: Phytochemistry and Bioactivities-A Review.

Herein, a comprehensive review is given focusing on the chemical profiles of the essential oils (EOs), non-volatile compounds, ethnobotany, and biological activities of different Haplophyllum (Rutaceae family) species. To gather the relevant data, all the scientific databases, including Scopus, ISI-WOS (Institute of Scientific Information-Web of Science), and PubMed and highly esteemed publishers such as Elsevier, Springer, Taylor and Francis, etc., were systematically retrieved and reviewed. A wide array of valuable groups of natural compounds, e.g., terpenoids, coumarins, alkaloids, lignans, flavonoids, and organic acids have been isolated and subsequently characterized in different organic extracts of a number of Haplophyllum species. In addition, some remarkable antimicrobial, antifungal, anti-inflammatory, anticancer, cytotoxic, antileishmanial, and antialgal effects as well as promising remedial therapeutic properties have been well-documented for some species of the genus Haplophyllum.

Exploring cardioprotective potential of esculetin against isoproterenol induced myocardial toxicity in rats: in vivo and in vitro evidence

BackgroundEsculetin is a natural coumarin derivative from various plants with multiple pharmacological effects. Hence, the present study was undertaken to explore the cardio protective potential of esculetin against isoproterenol induced myocardial toxicity in rats.MethodsThe treatment schedule was fixed for 28 days and the rats were divided into five groups of six each. Rats of group I received the normal saline and served as normal control, group II was received ISO (100 mg/kg body weight) for last two consecutive days of the study and served as disease control. Groups III and IV received esculetin 10 and 20 mg/kg body weight respectively once a day per oral for 28 days along with ISO for last two consecutive days of the study. Cardiac biomarkers such as CK-MB and LDH, membrane bound Na+ /K+ ATPases activity, myocardial lysosomal enzymes activity and tissue antioxidants status were estimated in the heart tissue samples. The histopathological changes in the myocardium were also assessed. Further, DPPH assay was done to evaluate the free radicals scavenging potential of esculetin. Cytoxicity assay, intracellular ROS levels by DCFDA assay and m-RNA expression of TNF-α, IL-6 and NF-κB by quantitative RT-PCR in H9c2 cell lines.ResultsThe increased levels of CK-MB, LDH, LPO, myocardial lysosomal enzymes and membrane bound Na+ /K+ ATPase levels by ISO administration was significantly increased with concomitant decrease in tissue antioxidant enzymes such as GSH, Catalase, and SOD. Pre-treatment with esculetin for 28 days has significantly decreased the levels of cardiac bio-markers, lysosomal enzymes, membrane bound Na+ /K+ ATPase levels as well as Lipid peroxides which is in contrary to the ISO group. Amelioration of the antioxidant levels were also found in esculetin treated groups. Histopathological examination of heart reveals that myocardial degeneration, mononuclear cell infiltration was noticed in ISO treated rats, whereas the same was restored with esculetin treatment. In H9C2 cell lines esculetin could effectively reduced intracellular ROS inhibition and m-RNA expression of pro-inflammatory cytokines including TNF-α, IL-6 and NF-κB to prevent apoptosis or cell necrosis.ConclusionThe study provides the evidence of cardioprotective potentials of esculetin against isoproterenol induced myocardial infarction by antioxidant and myocardial membrane stabilization along with in vitro protection from arsenic induced ROS cell necrosis or apoptosis in H9C2 cells.

Bioactivity of Some Natural and Semisynthetic Coumarin Derived Compounds

A couple of natural coumarins was identified in the seeds of two apples’ cultivars commonly known as Granny Smith and Red Delicious. The effect of the phenolic hydroxyl moieties found in these products was evaluated on the bioactivity. This evaluation included the structural alteration of these moieties into less hydrophilic ones to explore the significance of the parent moieties on the biological activity. The investigated biopotentials were antioxidant, antiproliferative, antibacterial, and antifungal effects. The antioxidant potential was investigated by detecting the ability of the natural and semisynthetic coumarins to trap the free hydroxyl and DPPH radicals. The antiproliferative potential was assessed via an MTT-depended assay versus eight cancerous-cell lines, included HeLa, SK-OV-3, AR42J, MCF-7, AB12, KYSE-30, LC540, and AMN3. The antibacterial potential was tested versus six common pathogenic bacterial strains via a well-defined disc diffusion assay. These pathogens were Escherichia coli, Salmonella typhi, Klebsiella pneumonia, Haemophilus influenzae, Shigella dysenteriae, and Pseudomonas aeruginosa. The antifungal potential was also screened by utilizing a similar microbiological technique versus three pathogenic fungi, involved Candida albicans, Aspergillus flavus, and Aspergillus niger. It is concluded that the investigated chemical moiety has a positive influence on the antioxidant and antiproliferative potentials of the natural derivatives, and a negative one on their antibacterial and antifungal potentials.

Umbelliprenin Increases the M1/M2 Ratio of Macrophage Polarization and Improves the M1 Macrophage Activity in THP-1 Cells Cocultured with AGS Cells.

Background Gastric adenocarcinoma is the fifth most diagnosed malignancy in the world. The immune system consists of a heterogeneous mixture of macrophages that defense the body through phagocytosis and the production of different cytokines and chemokines. Tumors cause macrophages to polarize differently in the manner of their favorite growth and angiogenesis. Umbelliprenin, a natural sesquiterpene coumarin, has been shown to have anticancer properties against some tumors, including gastric adenocarcinoma. The aim of our study was to investigate the effect of umbelliprenin on the polarization of macrophages in addition to the measurement of some of the soluble factors they produce. Method The values of IC5 and IC50 for umbelliprenin in the AGS and THP-1 cells were estimated using the MTT assay. THP-1 cells were treated with 10 μM umbelliprenin, either alone or cocultured with AGS cells. Flow cytometry analysis of treated THP-1 cells was performed for CD68, CD86, and CD206 markers to evaluate M0, M1, and M2 macrophages polarization, respectively. AGS cells were assessed for apoptosis and necrosis by flow cytometry after labeling with Annexin V-FITC and propidium iodide. Interleukin- (IL-) 10 and IL-12 contents were measured in the supernatant by the ELISA method. Griess Reaction assay technique was used to determine nitric oxide (NO) concentration. Results The results of the MTT showed lower toxicity of umbelliprenin in THP-1 (IC50 = 75.79) compared to the AGS cell line (IC50 = 48.81). Umbelliprenin significantly increased the M1/M2 ratio. IL-10 content decreased significantly in the supernatant of M1 and M2 cells after umbelliprenin treatment, while IL-12 increased in the supernatant of M1 cells and decreased in the supernatant of the M2 cells. Umbelliprenin caused an increase in the NO in the supernatant of the M1 cells. Conclusion Umbelliprenin alters the macrophage's secretions and its phenotypes in favor of tumor suppression.

Design, synthesis, and herbicidal activity of novel phenoxypyridine derivatives containing natural product coumarin

In recent years, protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors have been widely studied as important agricultural herbicides. Our research focused on the design and synthesis of novel PPO inhibitor herbicides, through linking of a diphenylether pyridine bioisostere structure to substituted coumarins, which aims to enhance environmental and crop safety while retaining high efficacy. A total of 21 compounds were synthesized via acylation reactions and all compounds were characterized using infrared, 1 H NMR, 13 C NMR, and high-resolution mass spectra. The respective configurations of compounds IV-6 and IV-12 were also confirmed using single crystal X-ray diffraction. The bioassay results showed that the title compounds displayed notable herbicidal activity, particularly compound IV-6 which displayed better herbicidal activity in greenhouse and field experiments, crop selectivity and safety for cotton and soybean compared with the commercial herbicide oxyfluorfen. The work revealed that compound IV-6 deserves further attention as a candidate structure for a novel and safe herbicide. © 2021 Society of Chemical Industry.

In silico analysis and identification of antiviral coumarin derivatives against 3-chymotrypsin-like main protease of the novel coronavirus SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is a pandemic viral disease caused by SARS-CoV-2 that generated serious damages for both the human population and the global economy. Therefore, it is currently considered as one of the most important global health problems of human societies and there is an urgent need for potent drugs or vaccines which can effectively combat this virus. The chymotrypsin-like protease (3CLpro) of SARS-CoV-2 plays a key role in the viral replication inside the host and thus is a promising drug target to design and develop effective antiviral drugs against SARS and other coronaviruses. This study evaluated some antiviral coumarin phytochemicals as potential inhibitors of coronaviruses 3CLpro by in silico approaches such as molecular docking, ADMET prediction, molecular dynamics simulation, and MM-PBSA binding energy calculation. Natural coumarin derivatives were docked to the 3CLpro of SARS-CoV-2 and for further investigation, docked to the 3CLpro of SARS-CoV and MERS-CoV. The docking scores of these natural compounds were compared with 3CLpro referenced inhibitors (ritonavir and lopinavir) and co-crystal inhibitor N3. Molecular docking studies suggested more than half of the coumarin phytochemicals had favorable interaction at the binding pocket of the coronaviruses 3CLpro and exhibited better binding affinities toward 3CLpro than ritonavir and lopinavir. Most antiviral phytochemicals interact strongly with one or both the catalytic dyad residues (His41 and Cys145) and the other key residues of SARS-CoV-2 main protease. Further, MD simulation and binding free energy calculations using MM-PBSA were carried out for three 3CLpro-coumarin complexes and 3CLpro-N3/lopinavir. The results confirmed that the 3CLpro-glycycoumarin, 3CLpro-oxypeucedanin hydrate, and 3CLpro-inophyllum P complexes were highly stable, experience fewer conformation fluctuations and share a similar degree of compactness. Also, the pharmacokinetics and drug-likeness studies showed good results for the selected coumarin phytochemicals.Therefore, the coumarin phytochemicals could be used as antiviral agents in the treatment of COVID-19 after further studies.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11030-021-10230-6.

Optimization and application of green solvent extraction of natural bioactive coumarins from Lamiaceae and Asteraceae herbal plants

Simple coumarins, 2H-1-benzopyran-2-ones, represent group of natural bioactive compounds. They are considered as secondary metabolites in plants of Lamiaceae and Asteraceae families. In this study, heat assisted extraction with low transition temperature mixtures (LTTM) based on choline chloride and L-lactic acid were used for simultaneous extraction of esculin, umbelliferone, scoparone, 4-methylumbelliferone and herniarin from herbal plants prior their determination by HPLC method with fluorescence detection. The effect of LTTM composition on coumarins extraction was verified. Optimal extraction conditions included choline chloride/L-lactic acid/1,3-propanediol (1:2:1) extraction solvent, solid/liquid ratio 1/40 g/mL, treatment time 15 min, rotation speed 20 rpm and temperature 60 °C. Temperature was the most significant parameter affecting extraction efficiency, the extraction time was an important variable for penetration of solvent in the matrix. Proposed HPLC method was applicable in linear concentration ranges from 5 to 100 ng/mL (for esculin, umbelliferone, scoparone, 4-methylumbelliferone) and from 15 ng/mL to 100 ng/mL (for herniarin) (R2 ≥ 0.998). The limits of detection were 0.2–5.0 ng/mL. The recovery of the method was higher than 87.7% (RSD < 5.8%). The content of umbelliferone and herniarin in herbal plants were 11.49–68.38 μg/g. The use of LTTM extraction solvent, application the response surface methodology and Taguchi orthogonal arrays design of experiment for optimization of extraction conditions, were contribute to the green aspect of the developed method.

Phenoxypyridine derivatives containing natural product coumarins with allelopathy as novel and promising proporphyrin IX oxidase-inhibiting herbicides: Design, synthesis and biological activity study

To seek novel and safe protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors with excellent herbicidal activity. A series of novel phenoxypyridine derivatives containing natural product coumarins with allelopathy were designed and synthesized based on bioisosterism and active subunit combination in this research. Compounds W3.1 and W3.4, with the half-maximal inhibitory concentration (IC50) value of 0.02653 mg/L and 0.01937 mg/L, respectively, displayed excellent herbicidal activity in greenhouse. Their herbicidal activity was similar to commercial herbicide oxyfluorfen (IC50 = 0.04943 mg/L). The best field inhibitory effect of compounds W3.1 and W3.4 recorded was at doses of 450 g ai/ha and 300 g ai/ha, respectively. Compound W3.4 had the best herbicidal activity among all the target compounds in this paper. Molecular docking analysis revealed that compounds W3.1 and W3.4 could form a hydrogen bonds with the amino acid AGR-98 and a π-π superposition with the amino acid PHE-398, respectively, which was similar to the oxyfluorfen. The crop selectivity tests results indicated that maize, cotton and soybean showed high tolerance to compound W3.4. Compound W3.4 reduced the Ca and Cb contents of wheat and rice, but had less effect on maize, cotton and soybean. Selectivity of compound W3.4 in maize, cotton and soybean were appeared to be due to reduced absorption of the herbicide compared to wheat and rice. Compound W3.4 deserves further attention as a candidate structure for new herbicides.

Daphnetin ameliorates acute lung injury in mice with severe acute pancreatitis by inhibiting the JAK2\u2013STAT3 pathway

Severe acute pancreatitis (SAP) is often associated with pulmonary inflammation leading to acute lung injury. Daphnetin, a natural coumarin derivative, has been reported to exert anti-inflammatory effects. Here, we explored the effect and possible mechanism of daphnetin in a mouse model of SAP-associated lung injury induced by an intraperitoneal injection of l-arginine. The severity of pancreatic and lung injury is determined by histology and its score. Immunostaining of inflammatory and apoptotic cells was used to demonstrate lung tissue inflammation and apoptosis; ELISA analysis of serum and tissue cytokine levels; and western blotting and immunohistochemical staining for the activated Janus kinase 2 (JAK2)–signal transducer and activator of transcription protein 3 (STAT3) signalling pathway in lung tissues. Daphnetin pretreatment significantly reduced SAP-induced pancreatic and lung tissue damage, reduced interleukin-6 and tumour necrosis factor-α concentrations in both serum and lung tissues, reduced serum amylase and myeloperoxidase activities, and reduced macrophage (CD11b) and neutrophil (Ly6G) infiltration and cell apoptosis in the lung tissue. Moreover, SAP-induced phosphorylation of JAK2 and STAT3 in the lung tissue was also significantly diminished by the daphnetin pretreatment. These results indicated that daphnetin reduces SAP-associated lung tissue damage, likely by inhibiting the activation of JAK2–STAT3 signalling.

Butyrylcholinesterase-inhibiting natural coumarin molecules as potential leads

Seventeen natural coumarin derivatives; badrakemin (1), 14′-acetoxybadrakemin (2), badrakemone (3), 14′-acetoxybadrakemone (4), colladonin (5), colladonin acetate (6), 14′-acetoxycolladonin (7), karatavicinol (8), deltoin (9), smyrnioridin (10), marmesin (11), osthol (12), oxypeucedanin (13), oxypeucedanin hydrate (14), isoimperatorin (15), scopoletin (16), and umbelliprenin (17), were tested against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the sister enzymes that play a critical role in the pathology of Alzheimer’s disease as well as tyrosinase (TYR) as the target for Parkinson’s disease. The tested coumarins were more selective against BChE, where the coumarins 2, 5, 8, and 15 (IC50 = 30.3 μM, 29.2 μM, 37.2 μM, and 50.1 μM, respectively) displayed higher BChE inhibition than the reference (galanthamine, IC50 = 60.2 μM) at 100 μg/mL. Only four coumarins (2, 5, 9, and 15) showed inhibition against AChE. Binding conformations of the coumarins (2, 5, 8, 9, and 15) within the active sites of AChE and BChE were explored via molecular docking experiments. The docked compounds were oriented by the interactions with the oxyanion hole and the peripheral anionic site residues of AChE/BChE. The coumarin derivatives 1–17 was found to have no or low inhibition (2.03 ± 0.92 %–12.91 ± 0.40 %) against TYR at 100 μg/mL. Our findings revealed that coumarins could be promising lead compounds for designing novel anti-Alzheimer drug candidates.

Columbianadin Dampens In Vitro Inflammatory Actions and Inhibits Liver Injury via Inhibition of NF-κB/MAPKs: Impacts on ∙OH Radicals and HO-1 Expression.

Columbianadin (CBN), a natural coumarin isolated from Angelica decursiva, is reported to have numerous biological activities, including anticancer and platelet aggregation inhibiting properties. Here, we investigated CBN’s anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell activation and deciphered the signaling process, which could be targeted by CBN as part of the mechanisms. Using a mouse model of LPS-induced acute liver inflammation, the CBN effects were examined by distinct histologic methods using trichrome, reticulin, and Weigert’s resorcin fuchsin staining. The result showed that CBN decreased LPS-induced expressions of TNF-α, IL-1β, and iNOS and NO production in RAW 264.7 cells and mouse liver. CBN inhibited LPS-induced ERK and JNK phosphorylation, increased IκBα levels, and inhibited NF-κB p65 phosphorylation and its nuclear translocation. Application of inhibitors for ERK (PD98059) and JNK (SP600125) abolished the LPS-induced effect on NF-κB p65 phosphorylation, which indicated that ERK and JNK signaling pathways were involved in CBN-mediated inhibition of NF-κB activation. Treatment with CBN decreased hydroxyl radical (•OH) generation and increased HO-1 expression in RAW 264.7 cells. Furthermore, LPS-induced liver injury, as indicated by elevated serum levels of liver marker enzymes (aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) and histopathological alterations, were reversed by CBN. This work demonstrates the utility of CBN against LPS-induced inflammation, liver injury, and oxidative stress by targeting JNK/ERK and NF-κB signaling pathways.

Daphnetin ameliorated GM-induced renal injury through the suppression of oxidative stress and apoptosis in mice

Gentamicin (GM), an aminoglycoside antibiotic, is one of the most effective drugs used in the treatment of various types of bacterial infections, but the major adverse effect and drug-induced nephrotoxicity of GM limit its clinical applications. Daphnetin (Daph) is a natural coumarin derivative that is clinically used to treat rheumatoid arthritis and coagulopathy and exhibits antioxidant effects. However, the effect of Daph on GM-induced nephrotoxicity has not yet been elucidated. This study investigated Daph-mediated protection against GM-induced nephrotoxicity in mice and explored the underlying mechanisms of GM-induced renal dysfunction in mice. We found that Daph treatment significantly reduced GM-induced nephrotoxicity mainly by ameliorating renal injury in mice and attenuating cell damage in vitro. Mechanistically, we found that Daph upregulated the expression level of Nrf2 and its regulated antioxidant enzymes HO-1, NQO1, GCLC and GCLM in vivo and in vitro. GM upregulated the expression levels of NOX4, cleaved Caspase-3 and p53 and the BAX/BCL2 ratio in vivo to stimulate oxidative stress and apoptosis. However, Daph treatment significantly improved the oxidative stress and apoptosis caused by GM, thereby exerting antioxidative and antiapoptotic effects. Our study was the first to suggest that the natural product Daph protects against GM-induced nephrotoxicity through the activation of Nrf2 which regulates oxidative stress and apoptosis. The pharmacological activation of Nrf2 may be useful as a novel therapy to prevent renal injury.

Evaluation of Enhanced UV Protection Property of Dyed Cotton Fabrics Based on Inclusion Complex of β-cyclodextrin with Natural Coumarin Extracted from Cortex fraxini

Inclusion complex formed between β-cyclodextrin (β-CD) and natural coumarins extracted from Cortex fraxini were utilized to dye and enhancing the UV protection properties of cotton fabric. Natural coumarins were extracted from Cortex fraxini and the total amount of natural coumarins was evaluated. The inclusion complex of natural coumarins with β-CD were formed and analyzed by ultraviolet-visible spectrum, fluorescence spectroscopy, FTIR and TGA. The obtained results showed that a stoichiometry of 1:1 inclusion complex was formed and the fluorescence intensities and ultraviolet absorption of the natural coumarins were both enhanced by incorporating into β-CD. β-CD was grafted onto cotton fabric based on esterification of citric acid with cellulose and cyclodextrin in the presence of sodium hypophosphite. The grafted cotton fabric was then dyed with natural coumarins extraction of Cortex fraxini as natural ultraviolet absorbent to form stable inclusion complex. UV protection factor (UPF), UVA transmittance (TUVA) and UVB transmittance (TUVB), wrinkle recovery and tensile strength of dyed fabrics were evaluated and demonstrated that graft modification of fabrics with β-CD resulted enhancement in UV protection property and durability accompanied with increasing in wrinkle recovery properties and decreasing in tensile strength. Furthermore, apparent morphology, FTIR and TGA analysis of inclusion complexes loaded cotton fabrics and the relationship between structure and properties were investigated.

Daphnetin, a natural coumarin averts reserpine-induced fibromyalgia in mice: modulation of MAO-A.

Fibromyalgia is a common, chronic, and generalized pain syndrome that is often associated with comorbid depression. The etiology of fibromyalgia is complex; most researchers have documented that the hallmark symptoms are due to the central nervous system's abnormal functioning. Neurotransmitters such as serotonin, norepinephrine, and glutamate, have been reported to be key regulators of fibromyalgia syndrome. Daphnetin is a 7, 8 dihydroxy coumarin widely distributed in Thymelaeaceae family plants, possessing various activities such as anti-arthritic, anti-tumor, anti-malarial, and anti-parasitic. The present study was designed to explore the potential of daphnetin against reserpine-induced fibromyalgia in mice. In mice, a fibromyalgia-like state was achieved by injecting reserpine (0.5mg/kg, s.c) continuously for 3days. All behavioral tests were conducted on the 4th and 6th day of experimentation. Reserpine administration significantly increased the mechanical hypersensitivity in electronic von Frey (eVF) and pressure application measurement (PAM) tests. It also increased the immobility period and time to reach the platform in force swim test (FST) and Morris water maze (MWM) test, respectively. In the biochemical analysis, reserpine treatment upregulated the monoamine oxidase-A (MAO-A) activity and level of glutamate, tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and thiobarbituric acid reactive substances (TBARS). Whereas, it decreased the level of glutathione (GSH), dopamine, serotonin, and norepinephrine. Daphnetin pretreatment attenuated the behavioral and biochemical changes induced by reserpine. Thus, the current investigation results delineate that daphnetin might exert its protective effect by inhibiting inflammatory stress and MAO-A-mediated neurotransmitter depletion and oxidative stress.

Anti-breast Cancer Potential of Natural and Synthetic Coumarin Derivatives.

Breast cancer is the most frequent female cancer and one of the leading causes of cancer death in women. There are many chemotherapy agents available for the treatment of breast cancer. Still, the current therapeutic options have not fulfilled the desired outcomes, especially for drug-resistant breast cancer therapy. Thus, there is an urgent need to develop novel anti-breast cancer agents. Coumarin is ubiquitous in natural and synthetic bioactive compounds, and coumarin derivatives readily interact with a variety of enzymes and receptors in breast cancer cells. Moreover, the coumarin-based irosustat as the first-generation steroid sulfatase inhibitor in breast cancer is under clinical evaluation, revealing the potential of coumarin derivatives as novel anti-breast cancer agents. This review aims to describe the recent development of natural and synthetic coumarin derivatives with anti-breast cancer potential, covering the articles published from 2015 to 2020.

A Review on Anti-urease Potential of Coumarins.

Coumarins, a heterocyclic benzo-α-pyrones and naturally occurring ring structure that possess significant pharmacological properties, have attracted the attention of researchers and medicinal chemists to reveal the suitability of both natural and synthetic coumarins as drugs. Many compounds have been synthesized utilizing the basic coumarin structure. The diverse synthetic methods resulted in the synthesis of important coumarin derivatives that offer a wide range of biological properties as antimicrobial, anticancer, anti-inflammatory, antioxidant, antidiabetic and antidepressant that make them potential drug candidates. With a particular interest in ulcers, coumarins have shown potential inhibition against urease enzyme. In recent years, scientists have emphasized the anti-urease activity of coumarins due to their low toxicity. The aim of this review is to compile data from recent research about anti-urease activities of coumarins and structure-activity relationship studies of the coumarin ring structure. Investigation of different structural substitutions in coumarin rings may help researchers to design new compounds with strong and effective anti- urease abilities.

Insulin-Mimetic Dihydroxanthyletin-Type Coumarins from Angelica decursiva with Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitory Activities and Docking Studies of Their Molecular Mechanisms.

As a traditional medicine, Angelica decursiva has been used for the treatment of many diseases. The goal of this study was to evaluate the potential of four natural major dihydroxanthyletin-type coumarins—(+)-trans-decursidinol, Pd-C-I, Pd-C-II, and Pd-C-III—to inhibit the enzymes, protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase. In the kinetic study of the PTP1B enzyme’s inhibition, we found that (+)-trans-decursidinol, Pd-C-I, and Pd-C-II led to competitive inhibition, while Pd-C-III displayed mixed-type inhibition. Moreover, (+)-trans-decursidinol exhibited competitive-type, and Pd-C-I and Pd-C-II mixed-type, while Pd-C-III showed non-competitive type inhibition of α-glucosidase. Docking simulations of these coumarins showed negative binding energies and a similar proximity to residues in the PTP1B and α-glucosidase binding pocket, which means they are closely connected and strongly binding with the active enzyme site. In addition, dihydroxanthyletin-type coumarins are up to 40 µM non-toxic in HepG2 cells and have substantially increased glucose uptake and decreased expression of PTP1B in insulin-resistant HepG2 cells. Further, coumarins inhibited ONOO−-mediated albumin nitration and scavenged peroxynitrite (ONOO−), and reactive oxygen species (ROS). Our overall findings showed that dihydroxanthyletin-type coumarins derived from A. decursiva is used as a dual inhibitor for enzymes, such as PTP1B and α-glucosidase, as well as for insulin susceptibility.