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Rehana D.,The New College Autonomous | Rehana D.,Justice Basheer Ahmed Sayeed College for Women Autonomous | Mahendiran D.,The New College Autonomous | Rahiman A.K.,The New College Autonomous
Bioprocess and Biosystems Engineering | Year: 2017

Phytofabricated green synthesis of zinc oxide (ZnO) nanoparticles using different plant extracts of Azadirachta indica, Hibiscus rosa-sinensis, Murraya koenigii, Moringa oleifera, and Tamarindus indica for biological applications has been reported. ZnO nanoparticles were also synthesized by chemical method to compare the efficiency of the green synthesized nanoparticles. FT-IR spectra confirmed the functional groups involved in the green synthesis of ZnO nanoparticles and the powder XRD patterns of the ZnO nanoparticles revealed pure wurtzite structure with preferred orientation at (100) reflection plane. SEM and TEM analysis revealed the spherical shape of the synthesized ZnO nanoparticles with the particle size between 54 and 27 nm. The antioxidant activity was evaluated by five different free radical scavenging assays. The present study also intends to screen α-amylase and α-glucosidase activity of ZnO nanoparticles synthesized using natural sources, which may minimize the toxicity and side effects of the inhibitors used to control diabetes. The ZnO nanoparticles synthesized using T. indica extract displayed remarkable antioxidant and antidiabetic activities. © 2017 Springer-Verlag Berlin Heidelberg

Mahendiran D.,The New College Autonomous | Rahiman A.K.,The New College Autonomous
Materials Science and Engineering C | Year: 2017

A series of heteroleptic silver(I) complexes of the type [Ag(L1 − 3)(nap)] (1–3), where L1–3 = 4′-(4-substituted)-2,2′:6′,2″-terpyridines and nap = naproxen have been synthesized and characterized by elemental analysis and spectroscopic methods. The geometric parameters of the complexes were determined using UV–Vis and DFT calculations together with the IR spectral data. All the complexes adopted distorted tetrahedral geometry around silver(I) ion. The small HOMO-LUMO energy gap supports the bioefficacy of the complexes. DNA binding and melting experiments suggest the intercalative binding mode of the complexes to CT–DNA, which was further supported by molecular docking studies. The molecular docking studies of the heteroleptic silver(I) complexes with EGFR/VEGFR2 kinase receptors show hydrophobic, π-π, σ-π and hydrogen bonding interactions. All the complexes have been found to promote DNA cleavage through hydrolytic pathway. In vitro cytotoxicity activity of the complexes was tested against four human breast adenocarcinoma (MCF-7), cervical (HeLa), epithelioma (Hep-2) and hepatoma (HepG2) cancerous, and one normal human dermal fibroblasts (NHDF) cell lines by MTT reduction assay. The morphological study by Hoechst 33258 staining revealed that the complex 3 induces apoptosis much more effectively than the other complexes. Further, all the complexes increases the DNA synthesis in S phase with the corresponding reduction in G0–G1 and G2/M phase, which suggest the growth inhibition mechanism on HepG2 cells was DNA damage mediated S phase arrest. © 2017 Elsevier B.V.

Rajasekar M.,The New College Autonomous | Sreedaran S.,University of Madras | Prabu R.,University of Madras | Narayanan V.,University of Madras | And 3 more authors.
Journal of Coordination Chemistry | Year: 2010

Ni(II) and Cu(II) metal complexes of simple unsymmetrical Schiff-base ligands derived from salicylaldehyde/5-methylsalicylaldehyde and ethylenediamine or diaminomaleonitrile (DMN) were synthesized. The ligands and their complexes were characterized by elemental analysis, 1H NMR, FT IR, and mass spectroscopy. The electronic spectra of the complexes show d-d transitions in the region at 450-600 nm. Electrochemical studies of the complexes reveal that all mononuclear complexes show a one-electron quasi-reversible reduction wave in the cathodic region. ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry, with nuclear hyperfine spin 3/2. The copper(II) complexes show a normal room temperature magnetic moment value μeff = 1.70-1.74 BM which is close to the spin only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts were also carried out. The in vitro antimicrobial activity of the investigated compounds was tested against human pathogenic bacterias such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa and Escherichia coli. The antifungal activity was tested against Candida albicans. Generally, the metal complexes have higher antimicrobial activity than the free ligands. © 2010 Taylor & Francis.

PubMed | SRM University, Alagappa University, University of Madras and The New College Autonomous
Type: | Journal: Journal of photochemistry and photobiology. B, Biology | Year: 2015

Three new homodinuclear manganese(II) complexes of the type [Mn2L(1-3)(ClO4)(H2O)](ClO4)3 (1-3) have been synthesized via cyclocondensation of terephthalaldehyde with three different benzoylated pendants in the presence of manganese(II) perchlorate and characterized by spectroscopic methods. Cyclic voltammetric investigation of complexes (1-3) depict two quasi-reversible one electron reduction processes in the cathodic potential region (E(1)pc=-0.73 to-0.83 V, E(2)pc=-1.31 to -1.40 V) and two quasi-reversible one electron oxidation processes in the anodic potential region (E(1)pa=1.03 to 1.10 V, E(2)pa=1.69 to 1.77 V). Electronic absorption spectra of the complexes suggested tetrahedral geometry around the central metal ion. The observed low magnetic moment values (eff, 5.60-5.68 B.M.) of the complexes indicate the presence of an antiferromagnetic spin-exchange interaction between two metal centers, which was also supported by the broad EPR signal. All the compounds were tested for antibacterial activity against Gram (-ve) and Gram (+ve) bacterial strains. The binding studies of complexes with CT-DNA suggested minor-groove mode of interaction. Molecular docking studies were carried out in order to find the binding affinity of complexes with DNA and protein EGFR Kinase. The complexes are stabilized by additional electrostatic and van der Waals interaction with the DNA, and support minor groove mode of binding. The cleavage activity of complexes on pBR322 plasmid DNA displays efficient activity through a mechanistic pathway involving hydroxyl radicals. The cytotoxicity of complexes 2 and 3 have been tested against human liver adenocarcinoma (HepG2) cell line. Nuclear-chromatin cleavage has also been observed with propidium iodide (PI) staining and alkaline single-cell gel electrophoresis (comet assay) techniques.

PubMed | University of Pitesti, SRM University, Alagappa University and The New College Autonomous
Type: | Journal: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy | Year: 2015

A series of bis(phenoxo) bridged binuclear manganese(II) complexes of the type [Mn2L(1-3)](ClO4)2 (1-3) containing 3,5-dinitrobenzoyl pendant-arms have been synthesized by cyclocondensation of 2,6-diformyl-4-R-phenols (where R=CH3, C(CH3)3 or Br) with 2,2-3,5-dinitrobenzoyliminodi(ethylamine) trihydrochloride in the presence of manganese(II) perchlorate. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions. The UV-Vis spectra of complexes suggest the distorted octahedral geometry around manganese(II) nuclei. The EPR spectra of Mn(II) complexes show a broad signal with g value 2.03-2.04, which is characteristic for octahedral high spin Mn(2+) complex. The observed room temperature magnetic moment values of the Mn(II) complexes (5.60-5.62B.M.) are less than the normal value (5.92B.M.), indicating weak antiferromagnetic coupling interaction between the two metal ions. Electrochemical studies of the complexes show two distinct quasi-reversible one electron transfer processes in the cathodic (E(1)pc=-0.73 to -0.76V, E(2)pc=-1.30 to -1.36V), and anodic (E(1)pa=1.02-1.11V, E(2)pa=1.32-1.79V) potential regions. Antibacterial efficacy of complexes have been screened against four Gram (-ve) and two Gram (+ve) bacterial strains. The DNA interaction studies suggest that these complexes bind with CT-DNA by intercalation, giving the binding affinity in the order 1>2>3. All the complexes display significant cleavage activity against circular plasmid pBR322 DNA. Docking simulation was performed to insert complexes into the crystal structure of EGFR tyrosine kinase and B-DNA at active site to determine the probable binding mode.

PubMed | Rajeswari Vedachalam Government Arts College, Loyola College Autonomous and The New College Autonomous
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2015

In the title complex, [Hg(NCS)2(CH4N2S)2], the Hg(II) atom is four-coordinated having an irregular four-coordinate geometry composed of four thione S atoms of two thio-cyanate groups and two thio-urea groups. The S-Hg-S angles are 172.02(9) for the trans-thio-cyanate S atoms and 90.14(5) for the cis-thio-urea S atoms. The mol-ecular structure is stabilized by an intra-molecular N-HS hydrogen bond, which forms an S(6) ring motif. In the crystal, mol-ecules are linked by a number of N-HN and N-HS hydrogen bonds, forming a three-dimensional framework. The first report of the crystal structure of this compound appeared in 1966 [Korczynski (1966 ). Rocz. Chem. 40, 547-569] with an extremely high R factor of 17.2%, and no mention of how the data were collected.

PubMed | Pondicherry University and The New College Autonomous
Type: | Journal: Materials science & engineering. C, Materials for biological applications | Year: 2016

A series of heteroleptic mononuclear copper(II) complexes of the type [Cu(L(1-3))(diimine)]ClO4 (1-6) containing three tetrazolo[1,5-a]pyrimidine core ligands, ethyl 5-methyl-7-(2-hydroxyphenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate (HL(1)), ethyl 5-methyl-7-(4-diethylamino-2-hydroxyphenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate (HL(2)) or ethyl 5-methyl-7-(2-hydroxy-4-nitrophenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate (HL(3)), and two diimine coligands, 2,2-bipyridyl (bpy) or 1,10-phenanthroline (phen) have been synthesized and characterized by spectral methods. The geometry of complexes have been determined with the help of electronic absorption and EPR splitting patterns, which suggest four coordinated square planar geometry around copper(II) ion. The lowering of HOMO-LUMO band gap value of complex 4 implies its higher biological activity compared to other complexes. Antioxidant studies revealed that the complexes possess considerable radical scavenging potency against DPPH. The binding studies of the complexes with calf thymus DNA (CT-DNA) revealed groove mode of binding, which was further supported by docking simulation. The complexes 3 and 4 strongly inhibit the topoisomerase I, and also strongly interact with VEGFR2 kinase receptor via -, - and hydrogen bonding interaction. Gel electrophoresis experiments demonstrated the ability of the complexes to cleave plasmid DNA in the absence of activators. In vitro cytotoxic activities of the complexes were examined on three cancerous cell lines such as human lung (A549), cervical (HeLa) and colon (HCT-15), and two normal cells such as human embryonic kidney (HEK) and peripheral blood mononuclear cells (PBMCs). The live cell and fluorescent imaging of cancer cells were observed with acridine orange/ethidium bromide staining assay. All encouraging chemical and biological findings indicate that the complex 4 is a suitable candidate for drug target.

PubMed | St Xaviers College Autonomous, The New College Autonomous and Physics Research Center
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2015

The title mol-ecular salt, C5H6N3O2 (+) H2NO3S(-), was obtained from the reaction of sulfamic acid with 2-amino-5-nitro-pyridine. A proton transfer from sulfamic acid to the pyridine N atom occurred, resulting in the formation of a salt. As expected, this protonation leads to the widening of the C-N-C angle of the pyridine ring, to 122.9(3), with the pyridinium ring being essentially planar (r.m.s. deviation = 0.025). In the crystal, the ion pairs are joined by three N-HO and one N-HN hydrogen bonds in which the pyridinium N atom and the amino N atom act as donors, and are hydrogen bonded to the carboxyl-ate O atoms and the N atom of the sulfamate anion, thus generating an R (3) 3(22) ring motif. These motifs are linked by further N-HO hydrogen bonds enclosing R (3) 3(8) loops, forming sheets parallel to (100). The sheets are linked via weak C-HO hydrogen bonds, forming a three-dimensional structure. The O atoms of the nitro group are disordered over two sets of sites with a refined occupancy ratio of 0.737(19):0.263(19).

Eight water soluble mixed-ligand nickel(II) complexes of the type [NiL(1-4)(diimine)H2O](ClO4)2, (1-8) where L(1-4) = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2-bipyridyl (bpy) or 1,10-phenanthroline (phen) were synthesized and characterized by elemental analysis and spectroscopic methods. The uncoordinated perchlorate anions was ascertained form IR spectra of the complexes, and the absorption spectra reveal the octahedron geometry around nickel(II) ion with tridentate Schiff base ligand, diimine and a coordinated water molecule. Cyclic voltammograms of the complexes indicate the one-electron irreversible processes in the cathodic and anodic region. In vitro antioxidant activity proved the significant radical scavenging activity of the complexes against DPPH radical. The groove/electrostatic binding nature of complexes with CT-DNA (calf thymus deoxyribonucleic acid) were affirmed by absorption, hydrodynamic and voltammetric titration experiments and docking analysis. All the complexes exhibit significant cleavage activity on plasmid DNA via hydrolytic and oxidatively, in which the oxidative mechanism involves hydroxyl radicals and supports the possibility of minor-groove binding. The complex 4 shows significant topoisomerase I (Topo-I) inhibitory activity. The molecular modeling analysis of complexes with phosphatidylinositol-3-kinase (PI3K) receptor indicate the hydrogen bonding with Met1039, Asp837 and Leu1027, and hydrophobic interactions with Ser488, Asn498, Asp500, Gln662, Lys668, Ile844, Ile847, Ile850, Val941, Leu942, Leu1020, Met1034, Leu1035, Thr1037, Met1039, Gln1041 and Ile1051 of subdomain IIA of BSA. The complexes show - interaction between diimines and amino groups of Leu1030 and Arg839.

PubMed | The New College Autonomous
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2016

The asymmetric unit of the organic-inorganic title salt, (C10H28N4)[Cr2O7]2, comprises one half of an 1,4-bis-(3-ammonio-prop-yl)piperazinediium cation (the other half being generated by the application of inversion symmetry) and a dichromate anion. The piperazine ring of the cation adopts a chair conformation, and the two CrO4 tetra-hedra of the anion are in an almost eclipsed conformation. In the crystal, the cations and anions form a layered arrangement parallel to (001). N-HO hydrogen bonds between the cations and anions and additional C-HO inter-actions lead to the formation of a three-dimensional network structure.

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