Design, synthesis and bioactivity evaluation of 4-hydroxycoumarin derivatives as potential anti-inflammatory agents against acute lung injury and colitis.

Acute lung injury (ALI) and inflammatory bowel disease (IBD) are common inflammatory illnesses that seriously affect people's health. Herein, a series of 4-hydroxylcoumarin (4-HC) derivatives were designed and synthesized. The inhibitory effects of these compounds on LPS-induced interleukin-6 (IL-6) release from J774A.1 cells were then screened via ELISA assay, compound B8 showed 3 times more active than the lead compound 4-HC. The most active compound B8 had the IC50 values of 4.57 µM and 6.51 µM for IL-6 release on mouse cells J774A.1 and human cells THP-1, respectively. Furthermore, we also found that B8 could act on the MAPK pathway. Based on the target prediction results of computer virtual docking, kinase inhibitory assay was carried out, and it revealed that targeting IRAK1 was a key mechanism for B8 to exert anti-inflammatory activity. Moreover, B8 exerted a good therapeutic effect on the dextran sulfate sodium (DSS)-induced colitis model and liposaccharide (LPS)-induced ALI mouse models. The acute toxicity experiments indicated that high-dose B8 caused no adverse reactions in mice, confirming its safety in vivo. Additionally, the preliminary pharmacokinetic (PK) parameters of B8 in SD rats were also examined, revealing a bioavailability (F) of 28.72 %. In conclusion, B8 is a potential candidate of drug for the treatment of ALI and colitis.

Fishing antioxidant 4-hydroxycoumarin derivatives: synthesis, characterization, and in vitro assessments.

Coumarins represent a diverse class of natural compounds whose importance in pharmaceutical and agri-food sectors has motivated multiple novel synthetic derivatives with broad applicability. The phenolic moiety in 4-hydroxycoumarins underscores their potential to modulate the equilibrium between free radicals and antioxidant species within biological systems. The aim of this work was to assess the antioxidant activity of 18 4-hydroxycoumarin coumarin derivatives, six of which are commercially available and the other 12 were synthesized and chemically characterized and described herein. The 4-hydroxycoumarins were prepared by a two steps synthetic strategy with satisfactory yields. Their antioxidant potential was evaluated through three in vitro methods, two free radical-scavenging assays (DPPH• and ABTS•+) and a metal chelating activity assay. Six synthetic coumarins (4a, 4g, 4h, 4i, 4k, 4l) had a scavenging capacity of DPPH• higher than butylated hydroxytoluene (BHT) (IC50 = 0.58 mmol/L) and compound 4a (4-hydroxy-6-methoxy-2 H-chromen-2-one) with an IC50 = 0.05 mmol/L outperformed both BHT and ascorbic acid (IC50 = 0.06 mmol/L). Nine hydroxycoumarins had a scavenging capacity against ABTS•+ greater (C3, 4a, 4c) or comparable (C1, C2, C4, C6, 4g, 4l) to Trolox (IC50 = 34.34 µmol/L). Meanwhile, the set had a modest ferrous chelation capacity, but most of them (C2, C5, C6, 4a, 4b, 4h, 4i, 4j, 4k, 4l) reached up to more than 20% chelating ability percentage. Collectively, this research work provides valuable structural insights that may determine the scavenging and metal chelating activity of 4-hydroxycoumarins. Notably, substitutions at the C6 position appeared to enhance scavenging potential, while the introduction of electron-withdrawing groups showed promise in augmenting chelation efficiency.

Synthesis, Crystallographic, Quantum Chemical, Antitumor, and Molecular Docking/Dynamic Studies of 4-Hydroxycoumarin-Neurotransmitter Derivatives.

In this contribution, four new compounds synthesized from 4-hydroxycoumarin and tyramine/octopamine/norepinephrine/3-methoxytyramine are characterized spectroscopically (IR and NMR), chromatographically (UHPLC-DAD), and structurally at the B3LYP/6-311++G*(d,p) level of theory. The crystal structure of the 4-hydroxycoumarin-octopamine derivative was solved and used as a starting geometry for structural optimization. Along with the previously obtained 4-hydroxycoumarin-dopamine derivative, the intramolecular interactions governing the stability of these compounds were quantified by NBO and QTAIM analyses. Condensed Fukui functions and the HOMO-LUMO gap were calculated and correlated with the number and position of OH groups in the structures. In vitro cytotoxicity experiments were performed to elucidate the possible antitumor activity of the tested substances. For this purpose, four cell lines were selected, namely human colon cancer (HCT-116), human adenocarcinoma (HeLa), human breast cancer (MDA-MB-231), and healthy human lung fibroblast (MRC-5) lines. A significant selectivity towards colorectal carcinoma cells was observed. Molecular docking and molecular dynamics studies with carbonic anhydrase, a prognostic factor in several cancers, complemented the experimental results. The calculated MD binding energies coincided well with the experimental activity, and indicated 4-hydroxycoumarin-dopamine and 4-hydroxycoumarin-3-methoxytyramine as the most active compounds. The ecotoxicology assessment proved that the obtained compounds have a low impact on the daphnia, fish, and green algae population.

Synthesis, computational study and cytotoxicity of 4-hydroxycoumarin-derived imines/enamines.

In this study, we applied a direct condensation between 3-acetyl-4-hydroxy-2H-chromen-2-one and different amines (anilines and benzyl amines) in order to synthesize some coumarin-based imines/enamines (3a-o) as cytotoxic agents. All the compounds were characterized by means of FT-IR, NMR, mass spectroscopy and elemental analyses. Since the title compounds can exist as different forms including (s-cis)-imine and (s-trans)-imine or (E and Z)-enamines, their conformational and geometrical aspects were investigated computationally by DFT method. The optimized geometry parameters, ΔE, ΔG, ΔH, Mulliken atomic charge, HOMO and LUMO energy, and NBO analysis suggested that these compounds can exist predominantly in (E)-enamine form. All the synthesized compounds (3a-o) were evaluated in vitro for their cytotoxic activities against cancer cell lines (MCF-7 and A549) and normal cell line (BEAS-2B) using the MTT assay. The 4-hydroxybenzyl derivative 3k was found to be the most potent cytotoxic agent with no selectivity, similar to doxorubicin. However, the 4-chlorobenzyl analog 3o could be considered as an equipotent compound respect to doxorubicin with higher selectivity.

Synthesis and Evaluation of 4-Hydroxycoumarin Imines as Inhibitors of Class II Myosins.

Inhibitors of muscle myosin ATPases are needed to treat conditions that could be improved by promoting muscle relaxation. The lead compound for this study ((3-(N-butylethanimidoyl)ethyl)-4-hydroxy-2H-chromen-2-one; BHC) was previously discovered to inhibit skeletal myosin II. BHC and 34 analogues were synthesized to explore structure-activity relationships. The properties of analogues, including solubility, stability, and toxicity, suggest that the BHC scaffold may be useful for developing therapeutics. Inhibition of actin-activated ATPase activity of fast skeletal and cardiac muscle myosin II, inhibition of skeletal muscle contractility ex vivo, and slowing of in vitro actin-sliding velocity were measured. Several analogues with aromatic side arms showed improved potency (half-maximal inhibitory concentration (IC50) <1 µM) and selectivity (≥12-fold) for skeletal myosin versus cardiac myosin compared to BHC. Several analogues blocked neurotransmission, suggesting that they are selective for nonmuscle myosin II over skeletal myosin. Competition and molecular docking studies suggest that BHC and blebbistatin bind to the same site on myosin.

Development of a series of 4-hydroxycoumarin platinum(IV) hybrids as antitumor agents: Synthesis, biological evaluation and action mechanism investigation.

A series of new 4-hydroxycoumarin platinum(IV) complexes were designed, synthesized and evaluated as antitumor agents. All the title compounds display moderate to effective antitumor activities toward the tested cell lines and two prominent compounds were screened out with activities comparable to cisplatin and oxaliplatin. The mechanism investigation demonstrates that the platinum(IV) compounds could be reduced to bivalence and exert significant genotoxicity to tumor cells. Meanwhile the coumarin moiety endows the title compounds with cyclooxygenase inhibitory competence which might favour the reduction of tumor-related inflammation and further influence tumor proliferation. The coumarin platinum(IV) complex could effectively induce apoptosis of SKOV-3 cells through up-regulating the expression of caspase3 and caspase9. Furthermore, the conversion of platinum(II) drugs to platinum(IV) form via the conjunction with 4-hydroxycoumarin enhances the drug uptake in whole cells and DNA simultaneously. Moreover, the 4-hydroxycoumarin platinum(IV) complex could combine with human serum albumin via van der Waals force and hydrogen bond, which would influence their transport and bioactivities in vivo.

Synthesis, characterization and unravelling the molecular interaction of new bioactive 4-hydroxycoumarin derivative with biopolymer: Insights from spectroscopic and theoretical aspect.

In the progress of small molecule as drug candidates, 4-hydroxycoumarin based compounds bearing a crucial place as potent antibiotic agents with appreciable safety in drug invention. Being synthetically and easily obtainable, 4-hydroxycoumarin related compounds with planar structure have been promoted predominantly as DNA targeting agent. Nevertheless, here we elucidate the synthesis, characterization and theoretical study of bio-active small molecule 4-hydroxy-3,4'-bichromenyl-2,2'-dione (4HBD). Then we have illuminated the binding interactions of 4HBD with calf thymus DNA (ctDNA), which is particularly designed for biological application. Extensive investigations of the binding of 4HBD with ctDNA are provided by utilizing multi-spectroscopic and molecular docking approaches, including UV-vis absorbance, steady-state, time-resolved fluorescence spectroscopy and circular dichroism study. The calculated binding and quenching constant value from quantitative data analysis of absorption and emission spectroscopy shows that 4HBD binds to the ctDNA groove. Further confirmation of the same is found by comparative displacement and iodide quenching studies. Negative enthalpy, negative free energy and positive entropy change imply a hydrophobic force monitors the association of 4HBD with the biomacromolecule. Interestingly the small molecule (4HBD) shows potential anti-bacterial activity against the model pathogenic gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria. The noncytotoxic nature of the 4HBD is demonstrated in vitro with the help of MTT assay by normal kidney epithelial (NKE), breast cancer cells (MCF-7) and human prostate cancer cell (PC3) lines. Hemolytic assay exhibits insignificant hemolysis of human erythrocyte cells at the minimum inhibitory concentration (MIC) of these tested bacteria. In this regard the present invention of 4-hydroxycoumarin based antimicrobial and noncytotoxic 4HBD molecule holds future promise in the development of new antibiotics.

3-Substituted-4-hydroxycoumarin as a new scaffold with potent CDK inhibition and promising anticancer effect: Synthesis, molecular modeling and QSAR studies.

A new series of 3-substituted-4-hydroxycoumarin derivatives was designed, synthesized, and evaluated for CDK inhibiting and anticancer activities. All the synthesized target compounds showed remarkably high affinity and selectivity towards CDK1B, compared to flavopiridol, with Ki values in the low nanomolar range (Ki=0.35-0.88nM). Most of them elicited considerable inhibiting effect against CDK9T1 (Ki=3.26-23.45nM). Moreover, all the target compounds were tested in vitro against eighteen types of human tumor cell lines. The hydrazone 3a, N-phenylpyrazoline derivative 6b and 2-aminopyridyl-3-carbonitrile derivative 8c were the most potent anticancer agents against MCF-7 breast cancer cell line (IC50=0.21, 0.21 and 0.23nM, respectively). The target compounds 3a, 6b and 8c were further evaluated in MCF-7 breast cancer mouse xenograft model and showed in vivo efficacy at 10mg/kg dose. The docking study confirmed a unique binding mode in the active site of CDK1B with better score than flavopiridol. Quantitative structure activity relationship study was done and revealed a highly predictive power R(2) of 0.81.

Synthesis and biological evaluation of coumarin-based inhibitors of NAD(P)H: quinone oxidoreductase-1 (NQO1).

The synthesis is reported here of two novel series of inhibitors of human NAD(P)H quinone oxidoreductase-1 (NQO1), an enzyme overexpressed in several types of tumor cell. The first series comprises substituted symmetric dicoumarol analogues; the second series contains hybrid compounds where one 4-hydroxycoumarin system is replaced by a different aromatic moiety. Several compounds show equivalent or improved NQO1 inhibition over dicoumarol, both in the presence and in the absence of added protein. Further, correlation is demonstrated between the ability of these agents to inhibit NQO1 and computed binding affinity. We have solved the crystal structure of NQO1 complexed to a hybrid compound and find good agreement with the in silico model. For both MIA PaCa-2 pancreatic tumor cells and HCT116 colon cancer cells, dicoumarol shows the greatest toxicity of all compounds. Thus, we provide a computational, synthetic, and biological platform to generate competitive NQO1 inhibitors with superior pharmacological properties to dicoumarol. This will allow a more definitive study of NQO1 activity in cells, in particular, its drug activating/detoxifying properties and ability to modulate oncoprotein stability.

Synthesis, computational study and cytotoxic activity of new 4-hydroxycoumarin derivatives.

Six new 4-hydroxycoumarin derivatives have been synthesized. They were characterized by UV-vis, IR, (1)H NMR, (13)C NMR, mass spectral data, elemental analysis, TLC and melting point determination. The new 4-hydroxycoumarin derivatives are studied by computational methods--DFT (B3LYP) and force field methods (MM2 and OPLS), in order to optimize their geometry and calculate quantum-chemical properties and conformational analysis. Five new 4-hydroxycoumarin derivatives were tested for cytotoxic activity in two tumor cell lines--HL-60 and EJ. The obtained results are compared with the utilized anticancer drug melphalan. Two of these compounds--ethyl 2-[(3,4-dihydroxyphenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)methyl]-3-oxobutanoate (SS-16) and ethyl 2-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(3-nitrophenyl)methyl]-3-oxobutanoate (SS-21) show comparatively good cytotoxic properties. Their activity is weaker than melphalan. SS-16 seems to be more active than SS-21.

Antineoplastic activity of new lanthanide (cerium, lanthanum and neodymium) complex compounds.

Cerium (III), lanthanum (III) and neodymium (III) complexes with 3,3'-benzylidenebis[4-hydroxycoumarin] were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinated to the metal ion through both deprotonated hydroxyl groups; however, participation of the carbonyl groups in the coordination to the metal ion was also suggested. The evaluation of the cytotoxic activity of the novel lanthanide complexes on HL-60 myeloid cells revealed that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum and neodymium coordination compounds, the latter being the least active. Our data give us reason to conclude that the newly synthesized lanthanide complexes should be submitted to further more detailed pharmacological and toxicological evaluation.

Theoretical and spectroscopic evidence for coordination ability of 3,3'-benzylidenedi-4-hydroxycoumarin. New neodymium (III) complex and its cytotoxic effect.

Theoretical and spectroscopic studies of 3,3'-benzylidenedi-4-hydroxycoumarin (bhc) have been performed. B3LYP/6-31G* calculations reproduced the experimental molecular structure of bhc and showed two O-H...O asymmetrical intramolecular hydrogen bonds with O...O distances 2.638 and 2.696 A. The calculated Fukui functions and Molecular Electrostatic Potential for bhc and its deprotonated form, bhc(2-), predicted that the most probable reactive sites for electrophilic attack and hydrogen bonds are the carbonyl oxygens, followed by the hydroxyl oxygens. The coordination ability of 3,3'-benzylidenedi-4-hydroxycoumarin has been proved in a complexation reaction with neodymium (III) ion. The new neodymium (III) complex of bhc was studied by elemental analyses, conductivity and other physical properties, mass spectra, (1)H, (13)C NMR, UV-Vis and IR spectroscopy. The data obtained are in agreement with the metal:ligand ratio of 1:1, and the formula Nd(bhc(2-))(OH)(H(2)O), where bhc(2-)=C(25)H(14)O(6)(2-). The vibrational analysis of the neodymium (III) complex, free bhc, and its monomeric building block, 4-hydroxycoumarin, showed that in the Nd(III) complex the ligand coordinates to the metal ion through both deprotonated hydroxyl groups. The participation of both carbonyl groups in coordination to the metal ion was confirmed by the significant shift of nu(C=O) to lower wavenumber. The evaluation of the cytotoxic activity of the new Nd(III) complex on SKW-3 and HL-60/Dox cells revealed, that it is a potent cytotoxic agent and should be subset further to more detailed pharmacological and toxicological study.

Synthesis of 4-hydroxycoumarin and 2,4-quinolinediol derivatives and evaluation of their effects on the viability of HepG2 cells and human hepatocytes culture.

We report here the synthesis of aromatic coumarins and aromatic alpha-quinolones which were evaluated in vitro for their protective potentialities against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage on human liver cell death, i.e., human hepatoma HepG2 cell line and human hepatocytes in primary culture. We found that the presence of a benzylidene at the 3-position or a heterocycle with N and S heteroatoms on the benzopyrone or quinolone system was essential for the protective effect of these compounds against t-BHP-induced decrease in viability of cells. We found also that a methoxy group on the aromatic ring systems decreased this potential. t-BHP-induced cytotoxicity in primary cultures of human hepatocytes could be therefore prevented by these compounds suggesting that they could display hepatoprotective effects in humans.

Synthesis and antitumor activity of 4-hydroxycoumarin derivatives.

A series of 4-hydroxycoumarin derivatives was prepared and evaluated for antitumor activity. The key fragments were 2a-c, 5c, 12b, 13b, 17, and 18 which were prepared via dianion ring cyclization, Friedel-Crafts acylation, and Reformatsky reaction. Compound 20b showed the most potent antitumor activity among the total 12 derivatives and compounds 19a and 19b exhibited efficacy comparable to etoposide in vitro antitumor activity.