Synthesis of new series of 3-hydroxy/acetoxy-2-phenyl-4H-chromen-4-ones and their biological importance

Zirconium (IV)-3-hydroxy-2-tolyl-4H-chromen-4-one complex-the analytical and DFT studies

Trace determination of Zr(IV) was carried out by its complexation with a newly synthesized chromone derivative, 3-hydroxy-2-tolyl-4H-chromen-4-one (HToC) for the formation of a 1:4 (M:L) yellow-colored complex from the bicarbonate medium maintained at pH 7.90-8.13. The complex was extractable into the non-aqueous organic solvents showing maximum and stable color intensity in dichloromethane in the wavelength range 414-430 nm. The complex obeyed Beer's law showing linearity of calibration curve in the range 0.0-1.1 µg Zr(IV) ml^-1 with an optimum range of determination as 0.44-1.0 ppm Zr(IV) detected from the Ringbom plot. Molar absorptivity, specific absorptivity, and Sandell's sensitivity of thus prepared complex were ascertained, respectively as 4.1971 × 10⁴ l mol^-1 cm^-1, 0.4601 ml g^-1 cm^-1, and 0.0022 µg Zr(IV) cm^-2 at 420 nm. The linear regression equation being [Formula: see text] (Y = absorbance, X = µg Zr(IV) ml^-1) with the correlation coefficient of 0.9977 and detection limit of the procedure as 0.0729 µg ml^-1. Theoretical calculations were used to determine and compare structural and bonding properties of the Zr(IV)-HToC complex along with justification of the donor sites provided by ligand for complexation with respect to the metal. The consequences obtained were highly cogent with standard deviation of ± 0.0021 absorbance unit. The procedure was applied to various synthetic (some analogous to cooperate and nickel zirconium) and technical (reverberatory flue dust and water) samples with satisfactory results.

Lipophilicity as a Central Component of Drug-Like Properties of Chalchones and Flavonoid Derivatives

Lipophilcity is an important physico-chemical parameter that influences membrane transport and binding ability to action. Migration distance following complete elution of compounds was used to calculate different lipophilicity-related parameters. The aim of this study is to show that lipophilicity is a central component of thiazole chalcones and flavonoid derivatives regarding their drug-like properties. Experimental and computational methods were used. This study considers 44 previously synthesized compounds (thiazole chalcones, flavanones, flavones, 3-hydroxyflavones, and their acetylated derivatives). The concerned compounds have shown antitumoral hallmarks and antibacterial activity in vitro. The experimental method used to determine compounds’ lipophilicity was the reverse-phase thin layer chromatography (RP-TLC). Lipophilicity related parameters—isocratic retention factor (R_M), relative lipophily (R_M⁰), slope (b), chromatographic hydrophobic index (φ₀), scores of principal components (PC1/R_M)—were determined based on reverse-phase chromatography results.

Studies on the interaction of a synthetic nitro-flavone derivative with DNA: A multi-spectroscopic and molecular docking approach

Interaction of a ligand with DNA is often the basis of drug action of many molecules. Flavones are important in this regard as their structural features confer them the ability to bind to DNA. 2-(4-Nitrophenyl)-4H-chromen-4-one (4NCO) is an important biologically active synthetic flavone derivative. We are therefore interested in studying its interaction with DNA. Absorption spectroscopy studies included standard and reverse titration, effect of ionic strength on titration, determination of stoichiometry of binding and thermal denaturation. Spectrofluorimetry techniques included fluorimetric titration, quenching studies and fluorescence displacement assay. Assessment of relative viscosity and estimation of thermodynamic parameters from CD spectral studies were also undertaken. Furthermore, molecular docking analyses were also done with different short DNA sequences. The fluorescent flavone 4NCO reversibly interacted with DNA through partial intercalation as well as minor-groove binding. The binding constant and the number of binding sites were of the order 10⁴ M^-1 and 1 respectively. The binding stoichiometry with DNA was found to be 1:1. The nature of the interaction of 4NCO with DNA was hydrophobic in nature and the process of binding was spontaneous, endothermic and entropy-driven. The flavone also showed a preference for binding to GC rich sequences. The study presents a profile for structural and thermodynamic parameters, for the binding of 4NCO with DNA. DNA is an important target for ligands that are effective against cell proliferative disorders. In this regard, the molecule 4NCO is important since it can exert its biological activity through its DNA binding ability and can be a potential drug candidate.

Ultrasound-assisted synthesis and antimicrobial activity of tetrazole-based pyrazole and pyrimidine derivatives

New tetrazole-based pyrazole and pyrimidine derivatives were synthesized by an ultrasound irradiation method. All compounds were characterized by infrared spectroscopy (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass spectrometry (MS) and elemental analysis and assessed in vitro for their efficacy as antimicrobial agents against four bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa) and two fungi (Candida albicans, Aspergillus niger). Compounds 8a, 8e, 9a, 9b and 9e show potent activity against the tested strains compared to the reference drugs chloramphenicol and clotrimazole.