Synthesis, crystal structures, and anti-drug-resistant Staphylococcus aureus activities of novel 4-hydroxycoumarin derivatives

Acenocoumarol Exerts Anti-Inflammatory Activity via the Suppression of NF-κB and MAPK Pathways in RAW 264.7 Cells

The repurposing of already-approved drugs has emerged as an alternative strategy to rapidly identify effective, safe, and conveniently available new therapeutic indications against human diseases. The current study aimed to assess the repurposing of the anticoagulant drug acenocoumarol for the treatment of chronic inflammatory diseases (e.g., atopic dermatitis and psoriasis) and investigate the potential underlying mechanisms. For this purpose, we used murine macrophage RAW 264.7 as a model in experiments aimed at investigating the anti-inflammatory effects of acenocoumarol in inhibiting the production of pro-inflammatory mediators and cytokines. We demonstrate that acenocoumarol significantly decreases nitric oxide (NO), prostaglandin (PG)E₂, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Acenocoumarol also inhibits the expression of NO synthase (iNOS) and cyclooxygenase (COX)-2, potentially explaining the acenocoumarol-induced decrease in NO and PGE₂ production. In addition, acenocoumarol inhibits the phosphorylation of mitogen-activated protein kinases (MAPKs), c-Jun N terminal kinase (JNK), p38 MAPK, and extracellular signal-regulated kinase (ERK), in addition to decreasing the subsequent nuclear translocation of nuclear factor κB (NF-κB). This indicates that acenocoumarol attenuates the macrophage secretion of TNF-α, IL-6, IL-1β, and NO, inducing iNOS and COX-2 expression via the inhibition of the NF-κB and MAPK signaling pathways. In conclusion, our results demonstrate that acenocoumarol can effectively attenuate the activation of macrophages, suggesting that acenocoumarol is a potential candidate for drug repurposing as an anti-inflammatory agent.

A new coumarin compound DCH combats methicillin-resistant Staphylococcus aureus biofilm by targeting arginine repressor

Staphylococcus aureus infection is difficult to eradicate because of biofilm formation and antibiotic resistance. The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection necessitates the development of a new agent against bacterial biofilms. We report a new coumarin compound, termed DCH, that effectively combats MRSA in vitro and in vivo and exhibits potent antibiofilm activity without detectable resistance. Cellular proteome analysis suggests that the molecular mechanism of action of DCH involves the arginine catabolic pathway. Using molecular docking and binding affinity assays of DCH, and comparison of the properties of wild-type and ArgR-deficient MRSA strains, we demonstrate that the arginine repressor ArgR, an essential regulator of the arginine catabolic pathway, is the target of DCH. These findings indicate that DCH is a promising lead compound and validate bacterial ArgR as a potential target in the development of new drugs against MRSA biofilms.

Antimicrobial Effects of Chemical Compounds Isolated from Traditional Chinese Herbal Medicine (TCHM) Against Drug-Resistant Bacteria: A Review Paper

Infectious diseases caused by pathogenic bacteria seriously threaten human lives. Although antibiotic therapy is effective in the treatment of bacterial infections, the overuse of antibiotics has led to an increased risk of antibiotic resistance, putting forward urgent requirements for novel antibacterial drugs. Traditional Chinese herbal medicine (TCHM) and its constituents are considered to be potential sources of new antimicrobial agents. Currently, a series of chemical compounds purified from TCHM have been reported to fight against infections by drug-resistant bacteria. In this review, we summarized the recent findings on TCHM-derived compounds treating drug-resistant bacterial infections. Further studies are still needed for the discovery of potential antibacterial components from TCHM.

Crystal structure of ethyl 2-amino-4-(3,5-difluorophenyl)-7-methyl-5-oxo-4H,5H-pyrano[4,3-b]pyran-3-carboxylate, C18H15F2NO5

C18H15F2NO5, monoclinic, C2/c (no. 15), a = 26.896(3) Å, b = 9.005(3) Å, c = 13.737(2) Å, β = 94.971(11)°, V = 3314.6(13) Å3, Z = 8, R gt(F) = 0.0560, wR ref(F 2) = 0.1823, T = 293(2) K.

Crystal structure of ethyl 2-amino-4-(2-methoxyphenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carboxylate, C22H19NO6

C22H19NO6, monoclinic, P21/n (no. 14), a = 9.055(3) Å, b = 17.601(6) Å, c = 11.817(4) Å, β = 91.361(5)°, V = 1882.8(11) Å3, Z = 4, R gt(F) = 0.0368, wR ref(F 2) = 0.1038, T = 296(2) K.

Crystal structure of ethyl 4-(3-cyanophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C22H24N2O3

C22H24N2O3, orthorhombic, Pbca (no. 61), a = 15.333(11) Å, b = 14.146(11) Å, c = 17.640(13) Å, V = 3826(5) Å3, Z = 8, R gt(F) = 0.0533, wR ref(F 2) = 0.1431, T = 296 K.

Crystal structure of 2-amino-4-(3,5-dibromo-4-hydroxyphenyl)-7-methyl-5-oxo-2H,5H-pyrano[4,3-b]pyran-3-carbonitrile, C16H10Br2N2O4

C16H10Br2N2O4, monoclinic, P21/n (no. 14), a = 12.885(9) Å, b = 8.781(6) Å, c = 15.692(11) Å, β = 112.258(13)°, V = 1643.2(19) Å3, Z = 4, R gt(F) = 0.0526, wR ref(F 2) = 0.1284, T = 296(2) K.

A nano-composite of magnetite and hot-water-soluble starch: a cooperation resulting in an amplified catalytic activity on water

A cooperation between magnetite and hot-water-soluble starch led to an efficient catalytic activity of their nano-composite in the pseudo three-component synthesis of bis-coumarins and xanthenes.

Crystal structure of 2-amino-4-(2,4-dinitrophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile – ethanol (1:1), C21H16N4O8

C21H16N4O8, triclinic, P1̅ (no. 2), a = 8.3222(6) Å, b = 10.8926(7) Å, c = 11.6941(8) Å, α = 78.182(6)°, β = 86.960(6)°, γ = 76.646(6)°, V = 1009.53(12) Å3, Z = 2, Rgt(F) = 0.0556, wRref(F2) = 0.1850, T = 293 K.

One-pot synthesis of functionalized 4-hydroxy-3-thiomethylcoumarins: detection and discrimination of Co2+ and Ni2+ ions

A variety of 4-hydroxy-3-thiomethylcoumarin derivatives were synthesized via a one-pot three-component reaction catalysed by l-proline at room temperature. One of the derivative was used as fluorescence probe to monitor and distinguish Co²⁺ and Ni²⁺.

Synthesis and pharmacological evaluations of 4-hydroxycoumarin derivatives as a new class of anti-Staphylococcus aureus agents

OBJECTIVES

Due to the increasing prevalence of drug-resistant Staphylococcus aureus infection, we develop novel 4-hydroxycoumarin derivatives as antimicrobials.

METHODS

The antibacterial activity of 4-hydroxycoumarin derivatives against drug-susceptive S. aureus (ATCC 29213) and methicillin-resistant S. aureus (MRSA) were evaluated using minimal inhibitory concentration (MIC) assay; the activity of favourable compound was further observed using bacterial growth curves assay and in the MRSA infection mice.

KEY FINDINGS

Compared with dihydropyran derivatives, compound 1 as one of biscoumarins showed most potent activity with MIC values of 4-8 μg/ml and apparently inhibited the growth rate of S. aureus ATCC 29213 and USA300 strain in concentrations of both 16 and 32 mg/ml. In the mice infected with MRSA USA300, administration of 5 mg/kg compound 1 improved the animal survival rate to 66.7%, and improved the pathological change in lung tissue compared with the infection model animals. No significant cytotoxicity of compound 1 was observed on the umbilical vein endothelial cells (HUVECs) under the concentration of 800 μg/ml.

CONCLUSION

Compared with the dihydropyran derivatives, biscoumarins exhibited more promising activity against both drug-sensitive and drug-resistant S. aureus, and it is efficacious in treating MRSA infections in mouse models with a favourable safety in human cells.

New biscoumarin derivatives: synthesis, crystal structure, theoretical study and antibacterial activity against Staphylococcus aureus

Five novel biscoumarins 1–5 were synthesized and characterized. In these compounds, two classical asymmetrical intramolecular O–H···O hydrogen bonds were used to stabilize the whole structures and the HB energies were performed with the density functional theory (DFT) [B3LYP/6-31G*] method. The five compounds were evaluated for their in vitro antibacterial activities against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) by the means of minimum inhibitory concentration and time-kill curves.