Schiff bases of 4-(methylthio)benzaldehydes: Synthesis,characterization, antibacterial, antioxidant and cytotoxicity Studies

A series of new Schiff bases of 4-(methylthio)benzaldehyde derivatives 3(a-i) were synthesized by the reaction of 4-(methylthio)benzaldehyde with various amines 2(a-i). Newly synthesized compounds were characterized by elemental analyses, UV-visible, FT-IR, Mass and 1H NMR spectral studies. All compounds were evaluated for their in vitro antibacterial activity against clinically isolated strains i.e., E. Coli, P. Fluorescence, M. Luteus and B. Subtilis. These compounds were screened for their antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl (DPPH•) and ferrous ion chelating assay (Fe2+) methods. The cytotoxicity assay was performed by tryphan blue dye exclusion method. Compounds 3g, 3h and 3i exhibited good antibacterial activity when compared with other compounds in the series against tested pathogenic bacterial strains. All the compounds showed antioxidant activity, where compound 3b was the best radical scavenger and Fe2+ ion scavenger. These findings showed that the Schiff bases of 4-(methylthio)benzaldehyde derivatives possess antioxidant activity with different mechanism of actions towards the different free radicals tested. Among these derivatives, 3b and 3h had the strongest activity against human peripheral lymphocytes

mu-phenoxide bridged mixed ligand Cu(II) complex: Synthesis, 3D supramolecular architecture, DFT, energy frameworks and antimicrobial studies

As an essential class of heterocyclic derivatives, 8-hydroxyquinoline(HQ) and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TFTB) have a broad range of pharmaceutical applications and they are found to be excellent precursors for metal complexes and crystal engineering. The novel mixed ligand Cu(II) complex Cu-2(C8H4O2SF3)(2)(C9H6NO)(2)] has been synthesized using a metal salt and the above ligands in a 1:1:1 M ratio and characterized by FT-IR, UV-visible, SEM and EDAX techniques. Single crystal X-ray structure analysis reveals a centrosymmetric dinuclear form of the Cu(II) complex, linked by the obtuse phenolate oxygen atom, and the central Cu(II) ion adopts a distorted square pyramidal coordination geometry. The Cu(II) complex exhibits various intermolecular interactions, leading to the construction of R-2(2) (16), R-2(2) (10) and R-2(2) (20) supramolecular synthons. The existence of intermolecular interactions is supported by Hirshfeld surface analysis and quantified by 2D fingerprint plots. In addition, the 3D topology of the molecular packing is visualized through energy frameworks, which reveal the predominance of dispersion energy over other interaction energies. DFT calculations have been performed for the mixed ligand Cu(II) complex to study the optimal geometry, related reactive parameters and the HOMO-LUMO energy gap (0.8232 eV). Further, the Cu(II) complex was evaluated against MRSA and showed an MIC value of 15 mu g/mL. A time-killing assay for the Cu(II) complex was performed to study the antimicrobial effect with respect to time. A molecular docking study revealed the binding affinity of the Cu(II) complex to penicillin-binding protein 2, with an excellent binding score of -8.0 kcal/mol. (C) 2020 Elsevier Ltd. All rights reserved

A gradient based facile HPLC method for simultaneous estimation of antioxidants extracted from tea powder

A new simple, rapid and precise RP-HPLC method was developed for the extraction and quantitative estimation of caffeine (C), (−)-epigallocatechin gallate (EGCG), (+)-catechin(Ct), (−)-epicatechin(EC), and (−)-epicatechin gallate (ECG) (collectively named as Tea Powder Bioactives TPBAs) extracted from tea powder using different ratios of ethanol: water. The simultaneous determination of TPBAs was performed using the UV spectrophotometric method which employs the absorbance at 205 nm (λmax of caffeine and polyphenols). This method is a gradient based HPLC method with a flow rate of 0.8 mL/min using Inertsil ODS 100 × 4.6 mm, 3 μm column with methanol and ammonium dihydrogen phosphate (pH-2.8) as mobile phase. The method was validated in terms of specificity, precision, linearity, accuracy, limit of quantification (LOQ), and limit of detection (LOD). The linearity of the proposed method was investigated for concentration ranging between 0.5–60 μg/mL with regression co-efficient, R2 = 0.999–1.0. This method estimates all the TPBAs simultaneously with enhanced precision and linearity as per the ICH guidelines. Also, to confirm the individual TPBA, the antioxidant property of the each TPBA was analyzed which was commensurate with that of the previous reports