Qadeer K. Panhwar

Synthesis and evaluation of antioxidant and antibacterial properties of morin complexes

This study examines the interaction of Mg(II) and Ca(II) with morin (2′,3,4′,5,7-pentahydroxyflavone) in conjunction with the appraisal of antioxidant and biological properties of the complexes. The complexes were characterized by UV-Vis spectroscopy, FT-IR, 1H NMR, 13C NMR, thermal, and elemental analyses. The complexes have also been studied to determine metal : ligand stoichiometry. For antioxidant studies, it may be induced that complex formation increases the scavenging ability because of the differential and selective role of metals in free radical scavenging. The bioactivity studies show that both complexes have remarkable antibacterial properties against Micrococcus flavus and Staphylococcus aureus.

Synthesis of Cr(III)-Morin Complex: Characterization and Antioxidant Study

The complex formation between Cr(III) and morin was carried out in methanol and confirmed by analytical characterization using UV-Vis, IR, 1H NMR, and TG-DTA. UV-Vis shows significant bathochromic shift in benzoyl upon coordination as well as IR well illustrates the peak shift of C=O group and formation of a O–Cr(III) bond. Likewise, 1H NMR studies clarify that Cr(III) metal ion replaces the 5OH proton hence; 5-hydroxy-4-keto site is employed by morin in chelation to form six-membered stable ring system out of three available chelating sites. In addition, TG-DTA denotes the presence of coordinated and crystalline water molecules. The melting point of the complex was found to be 389°C by DSC. In addition, Cr(III)-morin complex was found to be a more potent antioxidant than morin as evaluated by DPPH• and FRAP methods.

Synthesis and properties of zirconium(IV) and molybdate(II) morin complexes

Morin, an excellent chelating agent, has been used to form complex with a metal cation (Zr4+) and a metal oxyanion ( ), isolating highly colored [Zr(C15H9O7)2(NO3)2] · 2H2O (1) and [MoO3(C15H9O7)2] · 3H2O (2). The structures were elucidated using different techniques (i.e., electrical conductance, elemental, and thermal analyses) as well as a series of spectroscopic techniques (i.e., UV-Vis, IR, and 1H NMR). The stoichiometry of the complexes is 1 : 2, confirmed by the molar ratio method. Zr4+ is useful for structural diagnosis of different flavonoids. The preferred site of complex formation of morin is the 3-hydroxy-4-keto system. Complex 2 is more stable than 1. Fluorescence and cyclic voltammetry were studied. Antioxidative study affirmed that both 1 and 2 are efficient antioxidants relative to morin.

Synthesis, characterisation, and antioxidant study of Cr(III)-rutin complex

The article describes the synthesis and characterisation of the Cr(III)-rutin complex along with an estimate of its antioxidant activity. The complex was characterised using elemental analysis, UV-VIS, IR, conductance data, thermal, and gravimetric analyses. In the UV-VIS study, a bathochromic shift of approximately 98 nm indicates the formation of a rutin complex by more than one chelating site. The FT-IR spectra clearly show the formation of the Cr—O bond between rutin and Cr(III) at 494 cm−1, while the thermal study shows the presence of eight coordinated water molecules in the complex. The gravimetric analysis quantitatively proves the presence of four chloride ions. From these data, the formula of the Cr(III)-rutin complex was deduced as [Cr2(C27H28O16)(H2O)8]Cl4. Moreover, the antioxidant study of the complex was evaluated by using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free-radical, ferric-reducing, and phosphomolybdenum assays, which show that the complex has a higher antioxidant activity than rutin.

Synthesis and Antimicrobial Activity of p-tetranitrocalix[4]arene Derivative

The present study demonstrates the synthesis and antimicrobial activity of the p-tetranitrocalix[4]arene (3). The microbial activity was determined against a variety of microorganisms, i.e., Gram-positive and Gram-negative bacterial strains such as Staphylococcus aureus ATCC 10231, Streptococcus viridans ATCC 12392, Escherichia coli ATCC 8739, as well as some fungal species including Aspergillus niger ATCC 16404, Aspergillus flavus ATCC 90906, and Candida albicans ATCC 32333. Kirby-Bauer well agar diffusion method was employed for the determination of antimicrobial activity. All the microorganisms were applied to a selective agar medium (Mueller Hinton Agar) for growth. It was observed that compound 3 is considerably effective against selected microorganisms. The MIC values were also evaluated. Thus, from the results it could be deduced that compound 3 may be a valuable addition to the therapeutic index.

Synthesis, Characterization and Microbial Evaluation of Metal Complexes of Molybdenum with Ofloxacin (Levo (S-form) and Dextro (R-form)) Isomers

The article describes the interaction of molybdenum with dextrofloxacin and levofloxacin (isomers of ofloxacin) antibiotic drugs. Characterization of compounds was made by UV-Vis, FT–IR, 1 H NMR, elemental and thermogravimetric analyses. The green colored Mo–dextrofloxacin and yellow colored Mo–levofloxacin complexes were isolated. After complete characterization, the chemical formulae of the complexes were established as [MoO 2 ( R -Oflox) 2 ] or [MoO 2 (Dextro) 2 ] and [MoO 2 (Levo) 2 ] or [MoO 2 ( S -Oflox) 2 ]. The microbial evaluation was made by well diffusion method for both ligands and their metal complexes against two bacterial strains, S. aureus and E. coli . It was observed that the antibacterial action of Mo–dextrofloxacin and Mo-levofloxacin was significantly higher than the dextrofloxacin and levofloxacin alone against S. aureus , while no action was observed against E. coli .

Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

ABSTRACT Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.

Synthesis, Characterization, and Exploration of Antimicrobial Activity of Copper Complex of Diamide Derivative of p-tert-butylcalix[4]arene

ABSTRACT Calixarenes are a versatile class of compounds, which possesses wide applications in various fields including biological as well as pharmaceutical sciences. In the present study, amide derivative of calix[4]arene (3) was synthesized and characterized by modern analytical techniques such as elemental analysis and Fourier transform infrared spectroscopy (FT-IR). Complexation property of 3 with essential metals was explored by UV-Vis spectroscopy. The results revealed that 3 shows good selectivity toward Cu2+. Jobs plot analysis suggests that 3 forms complex with Cu2+ in 1:2 stoichiometric ratio. Antimicrobial activity of 3 and its Cu2+ complex was also determined and it was observed that 3 is more efficient against R. stolonifer as compared to its action against bacteria, because for fungus it shows “Minimum Inhibitory Concentration” (MIC) value equal to 1.5 µg/mL, while for bacteria MIC is 3 µg/mL. However, it was found that complex is more efficient in action than 3. Oxidation state of metal, overtone concept, and Tweedys chelation theory justifies the increased activity of metal complex. Cu2+ complex shows higher antimicrobial activity toward Escherichia coli (E. coli) (Gram-negative) bacteria by showing MIC value 0.37 µg/mL. While for Staphylococcus albus (S. albus) (Gram-positive) bacteria and Rhizopus stolonifer (R. stolonifer) fungal species, it shows MIC value equal to 0.75 µg/mL.