Benzylidene-bis-(4-hydroxycoumarin) and benzopyrano-coumarin derivatives: synthesis, ¹H/¹³C-NMR conformational and X-ray crystal structure studies and in vitro antiviral activity evaluations

Green metrics in mechanochemistry

The development of new green methodologies and their broader adoption for promoting sustainable development in chemistry laboratories and industry play a significant role in society, due to the economic importance of chemistry and its widespread presence in everyday life. Therefore, a sustainable approach to chemistry contributes to the well-being of the worldwide population and complies with the United Nations Sustainable Development Goals (UN SDGs) and the European Green Deal. The review highlights how batch and continuous mechanochemical methods are an eco-friendly approach for organic synthesis, with a lower environmental footprint in most cases, compared to solution-based procedures. The assessment is objectively based on the use of green metrics (e.g., atom and real atom economy, E-factor, process mass intensity, material parameter recovery, Eco-scale, stoichiometric factor, etc.) and indicators (e.g. DOZN tool and life cycle assessment, LCA, studies) applied to organic transformations such as synthesis of the amide bond, carbamates, heterocycles, active pharmaceutical ingredients (APIs), porphyrins, porous organic polymers (POPs), metal- or acid-catalysed processes, multicomponent and condensation reactions, rearrangements, etc. The generalized absence of bulk solvents, the precise control over the stoichiometry (i.e., using agents in a stoichiometrically rather than in excess), and the more selective reactions enabling simplified work-up procedures are the distinctive factors, marking the superiority of mechanochemical processes over solution-based chemistry.

Mechanistic elucidations of sesquiterpenes ameliorating viral infections: A review

Sesquiterpenes are important in human health because they can treat viral infection, cardiovascular disease, and cancer. Sesquiterpenes have also been shown to increase the sensitivity of tumor cells to conventional pharmacological therapies, in addition to their antiviral effects. The present review article was drafted with an intention to gather information regarding sesquiterpenes and its medicinal importance. The role of sesquiterpenes in the endogenous production of sesquiterpenes by plants and fungi, as well as the mechanisms by which they are effective against viral infection, are discussed in this review. Different online libraries such as PUBMED, Sciencedirect, MEDLINE were assessed to gather information, additionally, books, magzagines, journals, and scientific newspapaers were also studied to make this article more informative. This review examines novel synthesis mechanisms, their cyclization, purification techniques, and the diverse ecological roles sesquiterpenes play in the plant producer, which varies according to the plant and the chemical under consideration. In this article, we have discussed the consequences of sesquiterpenes and their properties for future crop productivity. We have addressed the many forms of sesquiterpenes that have been shown to have antiviral activity in various diseases. The consequences of sesquiterpenes and their properties are very useful for future crop productivity. We have addressed the many forms of sesquiterpenes that have been shown to have antiviral activity in the treatment of various diseases. PRACTICAL APPLICATIONS: Novel synthesis mechanisms, their cyclization, purification techniques, and the diverse ecological roles of sesquiterpenes will be very helfpul in drug development process. Sesquiterpene lactones are shown in this review to have qualities that warrant further scientific investigation in order to stimulate preclinical and clinical trials leading to the creation of novel medications. For antiviral drug development, the sesquiterpenes are a good prospective lead molecule because they can suppress viral replication by disrupting vRNA production and viral protein production.

An Efficient and Versatile Deep Eutectic Solvent-Mediated Green Method for the Synthesis of Functionalized Coumarins

Herein, we report a green and efficient synthetic route for the construction of diverse functionalized coumarins in good-to-excellent yields (60-98%) via the Pechmann condensation. The optimized synthetic route involves a biodegradable, reusable, and inexpensive deep eutectic solvent (DES) of choline chloride and l-(+)-tartaric acid in a ratio of 1:2 at 110 °C. Interestingly, phloroglucinol and ethyl acetoacetate, upon reaction, furnished the functionalized coumarin (20) in 98% yield within 10 min. On the other front, the same DES at relatively lower reaction temperature (90 °C) was found to provide the bis-coumarins in decent yields (81-97%) within 20-45 min. Moreover, this particular method was found to be quite effective for large-scale coumarin synthesis without noteworthy reduction in the yields of the desired products. Noticeably, in this versatile approach, the DES plays a dual role as solvent as well as catalyst, and it was effectively recycled and reused four times with no significant drop-down in the yield of the product.

Coumarin Derivatives Exert Anti-Lung Cancer Activity by Inhibition of Epithelial–Mesenchymal Transition and Migration in A549 Cells

A series of coumarin derivatives and isosteres were synthesized from the reaction of triflic intermediates with phenylboronic acids, terminal alkynes, and organozinc compounds through palladium-catalyzed cross-coupling reactions. The in vitro cytotoxic effect of the compounds was evaluated against two non-small cell lung carcinoma (NSCLC) cell lines (A-549 and H2170) and a normal cell line (NIH-3T3) using cisplatin as a reference drug. Additionally, the effects of the most promising coumarin derivative (9f) in reversing the epithelial-to-mesenchymal transition (EMT) in IL-1β-stimulated A549 cells and in inhibiting the EMT-associated migratory ability in A549 cells were also evaluated. 9f had the greatest cytotoxic effect (CC₅₀ = 7.1 ± 0.8 and 3.3 ± 0.5 μM, respectively against A549 and H2170 cells) and CC₅₀ value of 25.8 µM for NIH-3T3 cells. 9f inhibited the IL-1β-induced EMT in epithelial cells by inhibiting the F-actin reorganization, attenuating changes in the actin cytoskeleton reorganization, and downregulating vimentin in A549 cells stimulated by IL-1β. Treatment of A549 cells with 9f at 7 µM for 24 h significantly reduced the migration of IL-1β-stimulated cells, which is a phenomenon confirmed by qualitative assessment of the wound closure. Taken together, our findings suggest that coumarin derivatives, especially compound 9f, may become a promising candidate for lung cancer therapy, especially in lung cancer promoted by NSCLC cell lines.

Date Palm as Source of Nutraceuticals for Health Promotion: a Review

PURPOSE OF REVIEW

Chronic diseases are problematic to health professional specially when using drugs throughout the course of life with un-tolerated side effects. Returning to nature through using nutraceuticals might have both protective and therapeutic effects. Date palm was claimed to be a good source of such nutraceuticals or functional food ingredients. The purpose of the present review was to spot light on the different phytochemicals, phytonutrients, and remedial effects of date palm (Phoenix dactylifera L.) in a goal to be utilized in form of nutraceuticals. The possible mechanisms of action of the remedial effects were among the aim of the study.

RECENT FINDINGS

A protein hydrolyzate prepared from date seed could prevent DNA mutation and susceptibility to cancer. In addition to cancer prevention, date palm fruit improved the treatment outcome of cancer pediatric patients and possesses anti-angiogenic activity as one of the important anticancer mechanisms of action. On the other hand, date seed extracts was recently reported to protect from ulcerative colitis. It seems that all the aforementioned remedial effect might be ascribed to immunoregulatory effect of date palm. These findings proposed that date palm is beneficial for health. Date palm fruit is a rich source of vitamins, minerals, dietary fibers, energy, and easily digestible and absorbable sugars that instantaneously replenish and revitalize the body specially after fasting condition. Mineral contents in date fruits include potassium, phosphorus, magnesium, and calcium. Diverse health claims were reported to belong to various parts of the tree including the edible part of fruits, the seeds, the leaves, spathe (an envelope-like structure that encloses male and female date palm flowers), and pollen grains due to the presence of different bioactive constituents. The main phytochemicals and phytonutrients reported in date palms are phenolic compounds, carotenoids, sterols, anthocyanins, and others. In folk medicine, date palm fruits are used for enhancing immunity and treating gastrointestinal tract disorders, edema, bronchitis, wound, cancer, as well as infectious diseases. However, the exact health benefits and remedial effects of date palm were not fully and deeply investigated. The present review focused on the bioactive constituents and the reported health benefits of date palm and proposed mechanism of action.

Pharmacological perspectives and molecular mechanisms of coumarin derivatives against virus disease

Infections caused by viruses are one of the foremost causes of morbidity and mortality in the world. Although a number of antiviral drugs are currently used for treatment of various kinds of viral infection diseases, there is still no available therapeutic agent for most of the viruses in clinical practice. Coumarin is a chemical compound which is found naturally in a variety of plants, it can also be synthetically produced possessing diverse biological effects. More recently, reports have highlighted the potential role of coumarin derivatives as antiviral agents. This review outlines the advances in coumarin-based compounds against various viruses including human immunodeficiency virus, hepatitis virus, herpes simplex virus, Chikungunya virus and Enterovirus 71, as well as the structure activity relationship and the possible mechanism of action of the most potent coumarin derivatives.

Design of Fluorescent Coumarin-Hydroxamic Acid Derivatives as Inhibitors of HDACs: Synthesis, Anti-Proliferative Evaluation and Docking Studies

Coumarin-hydroxamic acid derivatives 7a-k were herein designed with a dual purpose: as antiproliferative agents and fluorescent probes. The compounds were synthesized in moderate yields (30-87%) through a simple methodology, biological evaluation was carried out on prostate (PC3) and breast cancer (BT-474 and MDA-MB-231) cell lines to determine the effects on cell proliferation and gene expression. For compounds 7c, 7e, 7f, 7i and 7j the inhibition of cancer cell proliferation was similar to that found with the reference compound at a comparable concentration (10 μM), in addition, their molecular docking studies performed on histone deacetylases 1, 6 and 8 showed strong binding to the respective active sites. In most cases, antiproliferative activity was accompanied by greater levels of cyclin-dependent kinase inhibitor p21, downregulation of the p53 tumor suppressor gene, and regulation of cyclin D1 gene expression. We conclude that compounds 7c, 7e, 7f, 7i and 7j may be considered as potential anticancer agents, considering their antiproliferative properties, their effect on the regulation of the genes, as well as their capacity to dock to the active sites. The fluorescent properties of compound 7j and 7k suggest that they can provide further insight into the mechanism of action.

New derivatives of a natural nordentatin

New derivatives were obtained from natural nordentatin (1) previously isolated from the methanol fraction of Clausena excavata by an acylation method. Herein, we report ten new pyranocoumarin derivatives 1a–1j. Their structures were elucidated based on UV-vis, FT-IR, NMR, and DART-MS data. The α-glucosidase inhibition and anticancer activities of nordentatin (1) and its derivatives were also evaluated. The α-glucosidase inhibition assay exhibited that the derivatives 1b, 1d, 1e, 1f, 1h, 1i, and 1j possess higher inhibitory activity for α-glucosidase with IC50 values of 1.54, 9.05, 4.87, 20.25, 12.34, 5.67, and 2.43 mM, whereas acarbose was used as the positive control, IC50 = 7.57 mM. All derivatives exhibited a weak cytotoxicity against a cervical cancer (HeLa) cell line with the IC50 between 0.25 and 1.25 mM. They also showed moderate to low growth inhibition of a breast cancer (T47D) cell line with IC50 values between 0.043 and 1.5 mM, but their activity was lower than that of the parent compound, nordentatin (1) (IC50 = 0.041 mM).

A biscoumarin scaffold as an efficient anti-Zika virus lead with NS3-helicase inhibitory potential: in vitro and in silico investigations

Competitive NTPase inhibition and the potential binding to the RNA binding pocket of Zika NS3-helicase were observed using biscoumarin derivatives. The SAR was established, and MN-9 and MN-10 were identified as potent anti-Zika leads.

Inhibition of a novel coumarin on an aquatic rhabdovirus by targeting the early stage of viral infection demonstrates potential application in aquaculture

Spring viremia of carp virus (SVCV) is one of the most serious pathogens in aquaculture, resulting in devastating damage in cyprinid. In this study, we designed and synthesized a novel coumarin derivative (C3007) for evaluating its in vitro and in vivo anti-SVCV effects. Here, we determined that up to 25 mg/L C3007 significantly decreased SVCV protein gene expression levels in EPC cells by a maximum inhibitory rate of >95%. When C3007 was preincubated with SVCV, infectivity was significantly inhibited in vitro in a time-dependent manner, with complete inhibition at 25 mg/L. For in vivo studies, C3007 exhibited an anti-SVCV effect by substantially enhancing the survival rate of virus-infected fish via intraperitoneal injection. Although the horizontal transmission of SVCV was hindered by C3007 in a static cohabitation challenge model, it was not completely blocked, showing that the viral loads in recipient fish were obviously reduced. Thus, C3007 could potentially be used as a therapeutic agent with great potential in aquatic systems and may also be suitable for applications in pond aquaculture settings against viral transmission. Additionally, the C3007-preincubated virus induced an antiviral immune response with high levels of IFN expression, suggesting that C3007 pre-treatment could be used in vaccine development.

Antiviral effect of 7-(4-benzimidazole-butoxy)-coumarin on rhabdoviral clearance via Nrf2 activation regulated by PKCα/β phosphorylation

Coumarin forms an elite class of naturally occurring compounds that possess promising antiviral therapeutic perspectives. In the previous study, we designed and synthesized a coumarin derivative, 7-(4-benzimidazole-butoxy)-coumarin (BBC), to evaluate its antiviral activity on spring viraemia of carp virus (SVCV). In this study, our results show that BBC does not affect viral adhesion and delivery from endosomes to the cytosol, indicating BBC has no inhibitory activity in the early stage of viral infection. Further data are determined that BBC significantly declines SVCV-infected apoptosis and recovers caspase-3/8/9 activity. To reveal the pathway that affects Nrf2 translocation by BBC, we examine changes in protein kinase C (PKC) in EPC cells treated with BBC. We observe that BBC results in a higher phosphorylation of PKCα/β that is involved in the activation of erythroid 2-related factor 2 (Nrf2) phosphorylation to favor Nrf2 translocation to nucleus at 24 and 48 h. In addition, the results show that BBC also up-regulates both antiviral responses, heme oxygenase-1 (HO-1) expression and cellular IFN response. Overall, this mechanism of action provides a new therapeutic target for the treatment of SVCV infection, and these results suggest that treatment with BBC is effective in reducing SVCV infection and differently regulates SVCV-induced undesirable conditions.

Synthesis and antiviral activity of a new coumarin derivative against spring viraemia of carp virus

Coumarin as a lead structure have received a considerable attention in the last three decades for the discovery of antiviral agents. Our previous study indicated that imidazole coumarins possessed antiviral activities against SVCV. Based on the structure-activity relationship in that study, a new imidazole coumarin derivative, 7-(4-benzimidazole-butoxy)-coumarin (BBC), was designed, synthesized and its anti-SVCV activity was evaluated. By comparing inhibitory concentration at half-maximal activity (IC₅₀), we found that BBC (IC₅₀ = 0.56 mg/L) possessed a higher antiviral activity than those imidazole coumarins in our previous study. Besides, BBC can significantly inhibit cell death and reduce cellular morphological damage induced by SVCV. Our further data indicated that intraperitoneal injection of BBC increased the survival rate of zebrafish by 17.5%, decreased viral titer in fish body and inhibited SVCV glycoprotein expression in kidney and spleen. In uninfected zebrafish, the expression levels of ifnγ, ifnφ1, ifnφ2 and rig1 genes were up-regulated after BBC treatment, which indicated that BBC could activate interferon response. In addition, data of the antioxidant enzymes activities and results of the antioxidant enzymes-related genes expressions suggested BBC could reduce SVCV-induced oxidative damage in infected zebrafish. Altogether, BBC is expected to be a therapeutic agent against SVCV infection in the field of aquaculture.

Dicoumarol derivatives: Green synthesis and molecular modelling studies of their anti-LOX activity

Dicoumarol derivatives were synthesized in the InCl3 catalyzed pseudo three-component reactions of 4-hydroxycoumarin with aromatic aldehydes in excellent yields. The reactions were performed in water under microwave irradiation. All synthesized compounds were characterized using NMR, IR, and UV-Vis spectroscopy, as well as with TD-DFT. Obtained dicoumarols were subjected to evaluation of their in vitro lipid peroxidation and soybean lipoxygenase inhibition activities. It was shown that five of ten examined compounds (3e, 3h, 3b, 3d, 3f) possess significant potential of antilipid peroxidation (84-97%), and that compounds 3b, 3e, 3h provided the highest soybean lipoxygenase (LOX-Ib) inhibition (IC50 = 52.5 µM) and 3i somewhat lower activity (IC50 = 55.5 µM). The bioactive conformations of the best LOX-Ib inhibitors were obtained by means of molecular docking and molecular dynamics. It was shown that, within the bioactive conformations interior to LOX-Ib active site, the most active compounds form the pyramidal structure made of two 4-hydroxycoumarin cores and a central phenyl substituent. This form serves as a spatial barrier which prevents LOX-Ib Fe2+/Fe3+ ion activity to generate the coordinative bond with the C13 hydroxyl group of the α-linoleate. It is worth pointing out that the most active compounds 3b, 3e, 3h and 3i can be candidates for further examination of their in vitro and in vivo anti-inflammatory activity and that molecular modeling study results provide possibility to screen bioactive conformations and elucidate the mechanism of dicoumarols anti-LOX activity.

A new coumarin derivative plays a role in rhabdoviral clearance by interfering glycoprotein function during the early stage of viral infection

Coumarin forms an elite class of naturally occurring compounds that possess promising antiviral therapeutic perspectives. In this study, a coumarin derivative 7-[6-(2-methylimidazole) hexyloxy] coumarin (D5) was designed and synthesized to evaluate antiviral activity on a rhabdovirus, spring viraemia of carp virus (SVCV). Our results demonstrated that D5 had a robust antiviral activity with >90% inhibitory rate of SVCV expression in the host cells. And D5 significantly reduced viral-induced apoptosis and recovered virus-activated caspase-3/8/9 activities. Further data determined that SVCV could alter the cytoskeletal structure of EPC cells, characterized by a circumferential ring of microtubules and a disrupted microfilament organization, whereas cytoskeleton structure in D5-treated cells kept the normal morphology. Mechanistically speaking, D5 could interfere with SVCV replication inside or outside of cells through two different approaches. Before the process of virus entry into EPC cells, D5 had an impact on SVCV glycoprotein structure so as to disrupt viral binding to the cell surface or translocation to the cytosol. Another strategy for D5 to against SVCV was that D5 significantly suppressed SVCV-activated autophagy, which was beneficial for the host cells to restrict SVCV viral replication, accompanied by a higher phosphorylation of Akt-mTOR. In summary, our results revealed that D5 was effective in weakening SVCV infection and regulating SVCV-induced undesirable conditions, and this compound provided new therapeutic implications for the treatment of rhabdoviruses.

Evaluation on antiviral activity of coumarin derivatives against spring viraemia of carp virus in epithelioma papulosum cyprini cells

As one of the most serious pathogens in the freshwater aquatic environment, spring viraemia of carp virus (SVCV) induces a high mortality rate in several cyprinid fishes. In this study, we designed and synthesized a total of 44 coumarin derivatives to evaluate the anti-SVCV activity. By comparing the inhibitory concentration at half-maximal activity (IC₅₀), two imidazole coumarins (B4 and C2) were selected, with maximum inhibitory rates on SVCV more than 90%. Mechanistically, B4 or C2 did not affect viral adhesion and delivery from endosomes to the cytosol. Further, B4 and C2 could decline the apoptosis in SVCV-infected cells and the viral activated caspase-3, 8, 9 activities. Other results showed that SVCV induced the cytoskeletal structure to be a circumferential ring of microtubules near the nucleus, with occurring a disrupted microfilament organization. In comparison, cytoskeleton structure in drug-treated cells kept complete. In addition, the cellular microstructure in drug treatments showed no significant change; while SVCV-infected cells were seriously shrunk, and observed typical apoptotic features including cell shrinkage, volume reduction and cell blebbing. More importantly, B4 and C2 enhanced anti-oxidative enzyme gene expression and triggered the Nrf-2 pathway to keep balance of intracellular redox state. Therefore, the use of two imidazole coumarins (B4 and C2) could be a viable way of preventing and controlling SVCV infection.

Dietary Supplementation of Phoenix dactylifera Seeds Enhances Performance, Immune Response, and Antioxidant Status in Broilers

The date palm (Phoenix dactylifera) seeds were utilized in some traditional medical remedies and have been investigated for their possible health benefits. This proposed study wanted to assess the effect of date palm seeds (DPS) dietary supplementation in comparison to mannan-oligosaccharides (Bio-Mos®) and β-glucan over antioxidant and immunity events that have effect on growth and carcass performances of broilers. An aggregate of 180, one-day-old, chicks were raised in the wire-floored cages and allotted into control, Bio-Mos (0.1%  Bio-Mos), β-glucan (0.1%  β-glucan), DPS2 (2% date crushed seeds), DPS4 (4% date crushed seeds), and DPS6 (6% date crushed seeds) groups. Broilers in DPS2 and DPS4 groups showed significant variations (P < 0.05) in relative growth rate (RGR), feed conversion ratio (FCR), and efficiency of energy utilization in comparison to control group. Moreover, all DPS fed groups showed significant increases (P < 0.05) in serum reduced glutathione (GSH) values. Meanwhile, both serum interferon-gamma (IFN-γ) and interleukin-2 (IL-2) levels were significantly increased (P < 0.05) in DPS2. Consequently, obtained data revealed a substantial enhancement of performance, immunity, and antioxidant status by DPS supplementation in broiler that might be related to the antioxidant and immune-stimulant constituents of P. dactylifera seeds.

Therapeutic potential of coumarins as antiviral agents

Coumarins have received a considerable attention in the last three decades as a lead structures for the discovery of orally bioavailable non-peptidic antiviral agents. A lot of structurally diverse coumarins analogues were found to display remarkable array of affinity with the different molecular targets for antiviral agents and slight modifications around the central motif result in pronounced changes in its antiviral spectrum. This manuscript thoroughly reviews the design, discovery and structure-activity relationship studies of the coumarin analogues as antiviral agents focusing mainly on lead optimization and its development into clinical candidates.

Ethylene glycol promoted catalyst-free pseudo three-component green synthesis of bis(coumarin)s and bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s

An ethylene glycol promoted catalyst-free practically efficient and sustainable approach has been developed for the synthesis of several benzylidene-bis-(4-hydroxycoumarin)s and 4,[Formula: see text]-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s by the pseudo three-component reaction of an aldehyde with 4-hydroxycoumarin and 3-methyl-1-phenylpyrazol-5-one, respectively. Inexpensive, non-toxic, and easily available ethylene glycol used as the reaction solvent and promoter renders an efficient protocol in terms of catalyst-free reaction conditions, short reaction time, high yield, practical utility, and green approach.

Catalytic performance of a Keplerate-type, giant-ball nanoporous isopolyoxomolybdate as a highly efficient recyclable catalyst for the synthesis of biscoumarins

In continuation of our previous works on the application of (NH4)42[MoVI 72MoV 60O372(CH3COO)30(H2O)72], a Keplerate-type giant-ball nanoporous isopolyoxomolybdate, as a catalyst for a series of organic transformations, in this paper, we discovered that this new attractive catalyst has high catalytic activity in the synthesis of biscoumarins prepared by the reaction of 4-hydroxycoumarin and aromatic or aliphatic aldehydes in refluxing ethanol. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials. Furthermore, the catalyst could be recovered conveniently and reused efficiently such that a considerable catalytic activity still could be achieved after fifth run. Other beneficial features of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work-up procedure.

Coumarins as Potential Antioxidant Agents Complemented with Suggested Mechanisms and Approved by Molecular Modeling Studies

Syntheses of coumarins, which are a structurally interesting antioxidant activity, was done in this article. The modification of 7-hydroxycoumarin by different reaction steps was done to yield target compounds. Molecular structures were characterized by different spectroscopical techniques (Fourier transformation infrared and nuclear magnetic resonance). Antioxidant activities were performed by using various in vitro spectrophometric assays against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydrogen peroxide (H2O2). All compounds exhibited high efficiency as antioxidants compared to ascorbic acid. The highest efficiency scavenging activity was found for compound 3 (91.0 ± 5.0), followed by compounds 2 and 4 (88.0 ± 2.00; and 87.0 ± 3.00). Ascorbic acid C was used as a standard drug with a percentage inhibition of 91.00 ± 1.5. The mechanism of the synthesized compounds as antioxidants was also studied. Hartree-Fock-based quantum chemical studies have been carried out with the basis set to 3-21G, in order to obtain information about the three-dimensional (3D) geometries, electronic structure, molecular modeling, and electronic levels, namely HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), to understand the antioxidant activity for the synthesized compounds.