scholarly journals Synthesis, characterization and antioxidant activity of Schiff base and its metal complexes with Fe(II), Mn(II), Zn(II), and Ru(II) ions: Catalytic activity of ruthenium(II) complex

2018 ◽  
Vol 9 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Nevin Turan ◽  
Kenan Buldurun
Keyword(s):  
Antioxidant Activity ◽  
Metal Complexes ◽  
Antioxidant Activities ◽  
Magnetic Moments ◽  
Antioxidant Properties ◽  
Molar Conductance ◽  
Transfer Hydrogenation ◽  
Spectral Studies ◽  
Ft Ir

The synthesis, spectral, catalytic and antioxidant properties of ethyl-2-(2-hydroxy-3-methoxybenzylideneamino)-6-methyl-4,5,6-tetrahydrobenzo[b]thiophene-3-carboxylate (L) substituted iron(II), manganese(II), zinc(II), and ruthenium(II)-arene chlorides are described for the first time. The ligand and its metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, and spectral (1H NMR, 13C NMR, FT-IR, UV-Vis and Mass) techniques. The FT-IR spectra showed that the ligand can act as bidentate or tridentate. Magnetic moments and electronic spectral studies revealed an octahedral geometry for all the complexes obtained. The thermal behavior of the complexes showed that the water molecules were separated in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. Ru(II) complex was used as catalysts for the transfer hydrogenation of ketones. At the same time, the effect of various bases such as NaOH, KOH, KOBut and NaOAc as organic base were investigated in the transfer hydrogenation of ketones by 2-propanol as the hydrogen source. The complexes and ligand were tested in vitro for their antioxidant activity. The experimental results showed that Ru(II) complex had more potent antioxidant activities than Zn(II), Fe(II), Mn(II) complexes and parent ligand.

scholarly journals Synthesis, Neuroprotection, and Antioxidant Activity of 1,1′-Biphenylnitrones as α-Phenyl-N-tert-butylnitrone Analogues in In Vitro Ischemia Models

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1127 ◽  
Author(s):  
Beatriz Chamorro ◽  
David García-Vieira ◽  
Daniel Diez-Iriepa ◽  
Estíbaliz Garagarza ◽  
Mourad Chioua ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
Human Neuroblastoma ◽  
In Vitro Ischemia ◽  
Lipoxygenase Inhibition ◽  
Antioxidant Agent

Herein, we report the neuroprotective and antioxidant activity of 1,1′-biphenyl nitrones (BPNs) 1–5 as α-phenyl-N-tert-butylnitrone analogues prepared from commercially available [1,1′-biphenyl]-4-carbaldehyde and [1,1′-biphenyl]-4,4′-dicarbaldehyde. The neuroprotection of BPNs1-5 has been measured against oligomycin A/rotenone and in an oxygen–glucose deprivation in vitro ischemia model in human neuroblastoma SH-SY5Y cells. Our results indicate that BPNs 1–5 have better neuroprotective and antioxidant properties than α-phenyl-N-tert-butylnitrone (PBN), and they are quite similar to N-acetyl-L-cysteine (NAC), which is a well-known antioxidant agent. Among the nitrones studied, homo-bis-nitrone BPHBN5, bearing two N-tert-Bu radicals at the nitrone motif, has the best neuroprotective capacity (EC50 = 13.16 ± 1.65 and 25.5 ± 3.93 μM, against the reduction in metabolic activity induced by respiratory chain blockers and oxygen–glucose deprivation in an in vitro ischemia model, respectively) as well as anti-necrotic, anti-apoptotic, and antioxidant activities (EC50 = 11.2 ± 3.94 μM), which were measured by its capacity to reduce superoxide production in human neuroblastoma SH-SY5Y cell cultures, followed by mononitrone BPMN3, with one N-Bn radical, and BPMN2, with only one N-tert-Bu substituent. The antioxidant activity of BPNs1-5 has also been analyzed for their capacity to scavenge hydroxyl free radicals (82% at 100 μM), lipoxygenase inhibition, and the inhibition of lipid peroxidation (68% at 100 μM). Results showed that although the number of nitrone groups improves the neuroprotection profile of these BPNs, the final effect is also dependent on the substitutent that is being incorporated. Thus, BPNs bearing N-tert-Bu and N-Bn groups show better neuroprotective and antioxidant properties than those substituted with Me. All these results led us to propose homo-bis-nitrone BPHBN5 as the most balanced and interesting nitrone based on its neuroprotective capacity in different neuronal models of oxidative stress and in vitro ischemia as well as its antioxidant activity.

scholarly journals Synthesis, Characterization and Biological Evaluation of Fe(III) and Cu(II) Complexes with 2,4-Dinitrophenyl hydrazine and Thiocyanate Ions

2019 ◽  
Vol 31 (4) ◽  
pp. 780-784
Author(s):  
P. Manimaran ◽  
S. Balasubramaniyan
Keyword(s):  
Antioxidant Activity ◽  
Metal Complexes ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Ligand ◽  
Antimicrobial Activities ◽  
Biological Evaluation ◽  
Diffusion Method ◽  
Spectral Studies

The metal complexes of Fe(III) and Cu(II) were prepared by using 2,4-dinitrophenyl hydrazine (DNPH) and thiocyanate (SCN) with stirrer refluxed for about 6 h. The prepared Fe(III) and Cu(II) complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility and electronic spectrum, FT-IR spectral studies. The result suggested the octahedral geometry for Fe(III) and Cu(II) complexes. Powder X-ray diffraction indicate the crystalline nature of the metal complexes. The antimicrobial activities of the Fe(III) and Cu(II) complexes were tested with various micro organisms by disc diffusion method. The antimicrobial results indicate that the metal complexes are highly active with compared to the free ligand. The in vitro antioxidant activity of the free ligand and its metal complexes was assayed by radical scavenging activity (DPPH). The result proposed that Fe (III) and Cu(II) complexes exhibited strong antioxidant activity than that of the ligand.

scholarly journals Synthesis, Spectroscopic, and Antimicrobial Studies on Bivalent Nickel and Copper Complexes of Bis(thiosemicrbazone)

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Sulekh Chandra ◽  
Smriti Raizada ◽  
Monika Tyagi ◽  
Archana Gautam
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Copper Complexes ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Central Metal ◽  
Antimicrobial Studies

A series of metal complexes of Cu(II) and Ni(II) having the general composition[M(L)X2]with benzil bis(thiosemicarbazone) has been prepared and characterized by element chemical analysis, molar conductance, magnetic susceptibility measurements, and spectral (electronic, IR, EPR, mass) studies. The IR spectral data suggest the involvement of sulphur and azomethane nitrogen in coordination to the central metal ion. On the basis of spectral studies, an octahedral geometry has been assigned for Ni(II) complexes but a tetragonal geometry for Cu(II) complexes. The free ligand and its metal complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties.

scholarly journals TLC Profiling of Leaves Extracts of Some Aloe Threatened Species Endemic to Madagascar for Their Antioxidant Activity

2020 ◽  
Vol 2 (3) ◽  
pp. 653-662
Author(s):  
Rokiman Letsara ◽  
Rigobert Andrianantenaina ◽  
Gédéon Ngiala Bongo ◽  
Colette Masengo Ashande ◽  
Mahendra Ilmi S Matondang ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Ethanolic Extract ◽  
World Health ◽  
Leaf Extracts ◽  
Phytochemical Compounds ◽  
Vitro Model ◽  
Health Organization

The World Health Organization reported that at least 80% of populations rely on traditional medicine and medicinal plants for their primary health care. Due to their phytochemical compounds, the plants of the Aloe genus are reported to have high potential antiCovid-19 (and antioxidant properties. The aim of this study is to evaluate the in vitro antioxidant activity of some Malagasy endangered species of Aloe genus. The ethanolic extract of few Aloe of Madagascar leaf extracts was fractionated by liquid-liquid partition using hexane. In total 18 different fractions from 9 species have been used to determine their antioxidant activity through in vitro model by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Both hexanic extract and aqueous extract displayed antioxidant activities in four species. The most evident antioxidant activity was expressed by A. helenae.

scholarly journals Synthesis, Characterization and Biological Evaluation of Schiff Base Transition Metal Complexes Derived from 4-Nitrobenzene-1,2-diamine and 5-Chloroisatin

2020 ◽  
Vol 32 (9) ◽  
pp. 2324-2328
Author(s):  
NETRA PAL SINGH ◽  
KAUSHAL KUMAR ◽  
GAJENDRA KUMAR ◽  
ANUROOP KUMAR
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Magnetic Moments ◽  
Biological Evaluation ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Bacteria And Fungi

A series of transition metal complexes of the type [MLX2], where M = Mn(II), Fe(II), Co(II), Ni(II), X = Cl–/CH3COO– and L = Schiff base derived from 4-nitrobenzene-1,2-diamine and 5-chloroisatin have been synthesized and characterized by elemental analysis, molar conductance, IR, UV-visible, magnetic moments measurement, 1H & 13C NMR and mass spectral studies. On the basis of physico-chemical studies and spectral evaluation, an octahedral geometry have been proposed for all metal(II) complexes. The antimicrobial activity of ligand and its metal complexes have been additionally screened against bacteria and fungi. Metal(II) complexes show good activity as compared to ligand towards studied microorganisms and also metal complexes checked for their catalytic properties for benzoylation of phenol.

scholarly journals Synthesis, Thermal Characterization and in vitro Antibacterial Assessment of Co(II) and Cd(II) Complexes of Schiff Base Derived from Amoxicillin and Thiophene-2-carbaldehyde

2019 ◽  
Vol 31 (4) ◽  
pp. 951-959 ◽  
Author(s):  
N.K. Chaudhary ◽  
B. Guragain
Keyword(s):  
Metal Complexes ◽  
Biological Activities ◽  
Geometry Optimization ◽  
Thermal Characterization ◽  
Molar Conductance ◽  
Sem Analysis ◽  
Biological Data ◽  
Spectral Studies ◽  
Tetrahedral Geometry

A novel AMXTC2 ligand was prepared by simultaneous stirring and refluxing of an equimolar mixture of amoxicillin and thiophene-2-carbaldehyde in methanol and was further used to synthesize metal complexes by metalation with cobalt and cadmium salts, taking ligand metal ratio 2:1. They were characterized by elemental microanalysis, FT-IR, mass, UV-visible, 1H NMR, thermal analysis, magnetic moment and molar conductance measurements. The coordination sites in the ligand were verified by their comparative and extensive spectral studies. The detailed exploration of the data suggested octahedral geometry for Co-AMXTC2 and tetrahedral geometry for Cd-AMXTC2 complexes. The thermodynamic and kinetic parameters such as E*, ΔH*, ΔS* and ΔG* of various decomposition steps were calculated from TGA curves using the Coats-Redfern method. The molar conductivity data suggested non-electrolytic nature of the complexes. SEM analysis was done to observe their surface morphology. The geometry optimization of the proposed molecular structure of the complexes was achieved by running MM2 calculation in Gaussian supported Cs-ChemOffice Ultra-11 program software. The biological activities had been evaluated in vitro against E. coli, K. pneumonia, P. vulgaris and S. aureus pathogens in order to assess their antibacterial potency. The biological data revealed better growth inhibitory action of the ligand and metal complexes with bacterial pathogens.

scholarly journals Antioxidant Properties of a Traditional Vine Tea, Ampelopsis grossedentata

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 295 ◽  
Author(s):  
Kun Xie ◽  
Xi He ◽  
Keyu Chen ◽  
Jihua Chen ◽  
Kozue Sakao ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ultrasonic Treatment ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Tea Polyphenols ◽  
Related Factor ◽  
Quinone Oxidoreductase ◽  
Ampelopsis Grossedentata

Ampelopsis grossedentata, also called vine tea, has been used as a traditional beverage in China for centuries. Vine tea contains rich polyphenols and shows benefit to human health, but the chemical and antioxidant properties of vine tea polyphenols from different locations remain unclear. This study aims to investigate the chemical and antioxidant properties of vine tea from three major production areas in China including Guizhou, Hunan, and Guangxi Provinces. The highest amount of polyphenol from vine tea was extracted by 70% ethanol at 70 °C for 40 min with ultrasonic treatment. The major compound in vine tea polyphenols (VTP) was determined as dihydromyricetin (DMY) by high-performance liquid chromatography (HPLC) and the content was estimated as 21.42%, 20.17%, and 16.47% of dry weight basis from Hunan, Guizhou, and Guangxi products, respectively. The antioxidant activities were investigated in vitro and in culture hepatic cells. VTP and DMY showed strong 1,1-Diphenyl-2-picrylhydrazyl free radical (DPPH) scavenging ability and high oxygen radical absorption capacity (ORAC) value in vitro. VTP and DMY also increased the level of nicotinamide adenine dinucleotide phosphate (NADPH):quinone oxidoreductase (NQO1) in HepG2 cells. Moreover, VTP and DMY enhanced the level of nuclear factor erythroid 2-related factor 2 (Nrf2) and reduced the level of Kelch-like ECH-associated protein 1 (Keap1). Taken together, our data demonstrated that the extraction of vine tea by 70% ethanol with ultrasonic treatment is a novel method to efficiently obtain components possessing stronger antioxidant activity. Furthermore, the results from the culture cells suggest that the bioactive component of vine tea might exert the antioxidant activity by activating the cellular Nrf2/Keap1 pathway.

scholarly journals Spectroscopic and Biological Studies on Newly Synthesized Cobalt (II) and Nickel (II) Complexes with 2-Acetyl Coumarone Semicarbazone and 2-Acetyl Coumarone Thiosemicarbazone

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Sanjay Goel ◽  
Sulekh Chandra ◽  
Sudhanshu Dhar Dwivedi
Keyword(s):  
Magnetic Susceptibility ◽  
Metal Complexes ◽  
Antioxidant Activities ◽  
Molar Conductance ◽  
Metal Salts ◽  
Spectral Studies ◽  
Planar Geometry ◽  
Square Planar ◽  
Biological Studies ◽  
Infrared Spectral

Co(II) and Ni(II) complexes of general composition ML2X2(M = Co(II), Ni(II); X = Cl−,NO3 −) were synthesized by the condensation of metal salts with semicarbazone/thiosemicarbazone derived from 2-acetyl coumarone. The ligands and metal complexes were characterized by NMR, elemental analysis, molar conductance, magnetic susceptibility measurements, IR, and atomic absorption spectral studies. On the basis of electronic, molar conductance and infrared spectral studies, the complexes were found to have square planar geometry. The Schiff bases and their metal complexes were tested for their antibacterial and antioxidant activities.

A Study on Synthesis and Antioxidant Activity Comparison of Novel Stilbenebenzamide Compounds

2019 ◽  
Vol 15 ◽  
Author(s):  
Aleksandra Kładna ◽  
Paweł Berczyński ◽  
Oya Bozdağ Dündar ◽  
Irena Kruk ◽  
Beyza Torun ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Antioxidant Activities ◽  
Wide Spectrum ◽  
Antioxidant Properties ◽  
Butylated Hydroxytoluene ◽  
Hydroxyl Group ◽  
Antioxidant Power ◽  
Total Antioxidant

Background: Stilbene phytalexis (1,2-diphenyloethylen) and benzamide are beneficial for human health. To increase the stilbene ring activity, a new series of its derivatives containing benzamide structure was synthesized and evaluated for their in vitro antioxidant power. Methods: 1H nuclear magnetic resonance, mass spectroscopy, and chromatographic analyses were used to confirm the successful synthesis. The antioxidant properties were determined by the elimination of , HO , DPPH , ABTS+ radicals, total antioxidant status (TAS) and the ferric reducing antioxidant activities (TAC) measurements. Results: Stilbenebenzamide compounds showed a wide spectrum of antioxidant ability, however their total antioxidant power was weaker than those of butylated hydroxytoluene (BHT), ascorbic acid, and resveratrol. The highest antiradical activity towards and HO was shown by the compounds with structures containing amine group (SBEBA, SBA) ( : 37.7 – 38.0% and 40.8 – 43.5%, HO : 29.8%, 28.7% inhibition, respectively) at1.25 mM concentration. The antiradical power of SBEBA (0.29) in DPPH assay was lower than those of resveratrol (1.83), ascorbic acid (3.63) and BHT (4.09). The TAS values of the synthesized compounds ranged from 152.9±5.3 to 240.2±6.7µM trolox equivalent/gram (TE/g) and were much lower than those of BHT (1304±43.0), reservatrol (1360±29.0) and ascorbic acid (2782±39.7) µM TE/g. Similarly, the TAC values ranging from 29.7±0.9 to 41.5±1.6 µM TE were weaker than that of resveratrol (239.2 ±6.7 µM TE/g). Conclusion: The results suggest that the presence of hydroxyl group in stilbene ring should be considered in further design of stilbenebenzamide compounds to enhance their antioxidant activity.

scholarly journals Spectral, NLO, Fluorescence, and Biological Activity of Knoevenagel Condensate of β-Diketone Ligands and Their Metal(II) Complexes

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
S. Sumathi ◽  
C. Anitha ◽  
P. Tharmaraj ◽  
C. D. Sheela
Keyword(s):  
Metal Complexes ◽  
Second Harmonic ◽  
Biological Activities ◽  
Analytical Data ◽  
Structural Features ◽  
Considerable Effect ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Planar Geometry

Transition metal complexes of various acetylacetone-based ligands of the type ML (where M=  Cu(II), Ni(II), Co(II); L=  3-(aryl)-pentane-2,4-dione) have been synthesized. The structural features have been derived from their elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, H1NMR, mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are nonelectrolytic in nature. Spectroscopic and other analytical data of the complexes suggest square planar geometry for copper(II), cobalt(II), and nickel(II) complexes of 3-(3-phenylallylidene)pentane-2,4-dione and octahedral geometry for other metal(II) complexes. The redox behaviors of the copper(II) complexes have been studied by cyclic voltammetry. The free ligands and their metal complexes have been screened for their in vitro biological activities against bacteria and fungus. The metal(II) complexes are found to possess increased activities compared to those of the free ligands. All synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligands was found to have considerable effect compared to that of urea and KDP.

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