Synthesis, structure, DNA binding and oxidative cleavage activity of ternary (l-leucine/isoleucine) copper(II) complexes of heterocyclic bases

Six ternary α-amino acid copper(II) complexes of the general formula Cu(AA)(B)(H 2O)(X) (1-6), where AA is l-leu = l-leucine (1-3) or l-ile = l-isoleucine (4-6), B is a N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1, 4), 1,10-phenanthroline (phen, 2, 5) and dipyrido3,2:2â²,3â²-fquinoxaline (dpq, 3, 6) and X = ClO 4 - / NO 3 - have been synthesized, characterized, and their DNA binding and cleavage activity studied. The bpy and dpq complexes of l-ile (4, 6) have been structurally characterized by X-ray crystallography. The complexes show a distorted square-pyramidal (4 + 1) CuN 3O 2 coordination geometry. The one-electron paramagnetic complexes display a d-d band near 600 nm in water and show a cyclic voltammetric response due to a Cu(II)/Cu(I) couple near -0.1 V (vs. SCE) in DMF-0.1 M TBAP. All complexes are 1:1 electrolytes. Binding interactions of the complexes with calf thymus DNA (CT-DNA) have been investigated by absorption, emission, viscosity and DNA melting studies. The phen and dpq complexes are avid binders to the calf thymus DNA, giving an order: (3, 6) (dpq) > (2, 5) (phen) â« (1, 4) (bpy). The bpy complexes do not show any apparent binding to the DNA and hence show poor DNA cleavage activity. The phen and dpq complexes (2, 3, 5, 6) show efficient oxidative cleavage of pUC19 supercoiled DNA (SC-DNA) in the presence of the reducing agent 3-mercaptopropionic acid (MPA) involving hydroxyl radical ( {radical dot}OH) species, as evidenced from the control data showing inhibition of DNA cleavage in the presence of {radical dot}OH radical quenchers, viz. DMSO, mannitol, KI and catalase. © 2008 Elsevier Ltd. All rights reserved

DNA binding and oxidative cleavage activity of ternary (l-proline)copper(II) complexes of heterocyclic bases

Ternary copper(II) complexes Cu(l-pro)(B)(H 2O)(NO 3) (1, 2) where l-pro = l-proline, B is a N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), are synthesized, characterized, and their DNA binding and cleavage activity studied. The bpy complex (1) is structurally characterized by single-crystal X-ray crystallography. The complexes show the presence of a distorted square-pyramidal (4 + 1) CuN 3O 2 coordination geometry. Complex Cu(l-pro)(bpy)(H 2O)(NO 3) (1) crystallizes in the triclinic space group P1 with unit cell parameters: a = 7.082(3) à , b = 10.483(5) à , c = 11.581(5) à , α = 89.700(7)°, β = 83.488(8)°, γ = 84.109(8)° and V = 849.7(7) à 3. The one-electron paramagnetic complexes display a d-d band near 600 nm in water and show a cyclic voltammetric response due to Cu(II)/Cu(I) couple near 0.1 V (versus SCE) in Tris-HCl buffer-0.1 M KCl. Binding interactions of the complexes with calf thymus (CT) DNA have been investigated by emission, absorption, viscosity and DNA thermal denaturation studies. The phen complex displays significant binding propensity to the CT DNA giving an order: 2 (phen) â 1 (bpy). The bpy complex does not show any apparent binding to the DNA and hence poor cleavage efficiency. Complex 2 shows efficient oxidative cleavage of SC-DNA in the presence of 3-mercaptopropionic acid (MPA) involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and catalase. © 2007 Elsevier Ltd. All rights reserved

New ternary copper(II) complexes of l-alanine and heterocyclic bases: DNA binding and oxidative DNA cleavage activity

Four new ternary copper(II) complexes of α-amino acid having polypyridyl bases of general formulation [Cu(l-ala)(B)(H2O)](X) (1–4), where l-ala is l-alanine, B is an N,N-donor heterocyclic base, viz. 2,2′-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) and 5,6-phenanthroline dione (dione, 3), dipyrido[3,2:2′,3′-f]quinoxaline (dpq, 4), and X = View the MathML source/View the MathML source are synthesized, characterized by various spectroscopic and X-ray crystallographic methods. The complexes show a distorted square-pyramidal (4 + 1) CuN3O2 coordination geometry. The one-electron paramagnetic complexes (1–4) display a low energy d–d band near 600 nm in aqueous medium and show a quasi-reversible cyclic voltammetric response due to one-electron Cu(II)/Cu(I) reduction near −100 mV (versus SCE) in DMF–0.1 M TBAP. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV–Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. All the complexes barring the complexes 1 and 3 are avid binder to the CT-DNA in the DNA minor groove giving an order: 4 > 2 ⋙ 1, 3. The complexes 2 and 4 show appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA) as a reducing agent. Hydroxyl radical was investigated to be the DNA cleavage active species. Control experiments in the presence of distamycin-A show primarily minor groove-binding propensity for the complexes 2 and 4 to the DNA

Altered Ca(2+ )homeostasis in polymorphonuclear leukocytes from chronic myeloid leukaemia patients

BACKGROUND: In polymorphonuclear leukocytes (PMNL), mobilization of calcium ions is one of the early events triggered by binding of chemoattractant to its receptors. Besides chemotaxis, a variety of other functional responses are dependent on calcium ion mobilization. PMNL from chronic myeloid leukaemia (CML) patients that were morphologically indistinguishable from normal PMNL were found to be defective in various functions stimulated by a chemoattractant – fMLP. To study the mechanism underlying defective functions in CML PMNL, we studied calcium mobilization in CML PMNL in response to two different classical chemoattractants, fMLP and C5a. RESULTS: Release of calcium estimated by flow cytometry and spectrofluorimetry using fluo-3 as an indicator showed that the [Ca(2+)](i )levels were lower in CML PMNL as compared to those in normal PMNL. But, both normal and CML PMNL showed maximum [Ca(2+)](i )in response to fMLP and C5a at 10 sec and 30 sec, respectively. Spectrofluorimetric analysis of the total calcium release in chemoattractant treated PMNL indicated more and faster efflux of [Ca(2+)](i )in CML PMNL as compared to normal PMNL. CONCLUSION: Fine-tuning of Ca(2+ )homeostasis was altered in CML PMNL. The altered Ca(2+ )homeostasis may contribute to the defective functions of CML PMNL

Oxamido binuclear copper (II) complexes: Synthesis, crystal structure, DNA interaction and antibacterial studies

Four binuclear copper (II) complexes Cu(oxpn)Cu(B)2+ (2-5) bridged by N, Nâ²-bis3-(methylamino) propyl oxamide (oxpn), where, B is N, N-donor heterocyclic bases (viz. 2,2â²-bipyridine (bpy, 2), 1,10-phenathroline (phen, 3), dipyrido3,2-d:2â²,3â²-fquinoxaline (dpq, 4) and dipyrido3,2-a:2â²,3â²-cphenazine (dppz, 5) are synthesized, characterized by different spectroscopic and single crystal X-ray data technique. The phen (3) and dpq (4) complexes were structurally characterized by X-ray data analysis. Their DNA binding, oxidative cleavage and antibactirial activities were studied. The dpq (4) and dppz (5) complexes are avid binders to the Calf thymus DNA (CT-DNA). The phen (3), dpq (4) and dppz (5) complexes show efficient oxidative cleavage of supercoiled DNA (SC DNA) through hydroxyl radical (OH) pathway in the presence of Mercaptopropionic acid (MPA). © 2013 Elsevier Ltd. All rights reserved

Synthesis and Chemical Nuclease Activities of Copper (II) and Ni (II) Complexes of 4-Chloro-2-(pyridine-3-Yliminomethyl) Phenol Schiff Bases

This communication describes a procedure to synthesize a novel Schiff base ligand4-chloro-2-(pyridine-3-yliminomethyl) phenol and its transition metal complexes of Cu(II) and Ni(II)and its characterization by physiochemical techniques such as elemental, FTIR,UVVisible, 1 H-NMR, Mass spectra and cyclic voltammetry. Further, the ligand was structurally characterized by X-ray crystallography and is found to be planar suitable for DNA studies. The complexes were screened for their in-vitro antimicrobial activity using various strains of gram positive and gram negative bacteria- Bacillus mycoides, Bacillus subtilis, Escherichia coli, Micrococcus luteus, Proteus mirabilis, Pseudomonas aeruginosa and Yersinia enterocolitica. The Schiff base ligand showed higher antibacterial activity than the ligand coordinated to either of the metal ion copper or nickel. The DNA cleavage studies of the complexes have been investigated and both the complexes showed extensive cleavage of DNA. However, Cu(II) complexes showed better cleavage activity compared to Ni(II) complex

Oxidative DNA cleavage, cytotoxicity and antimicrobial studies of l-ornithine copper (II) complexes

New ternary copper (II) complexes, Cu(l-orn)(B)(Cl)(Cl·2H 2O) (1-2) where l-orn is l-ornithine, B is an N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1) and 1,10-phenanthroline (phen, 2), were synthesized and characterized by various spectroscopic techniques. Complex 2 is characterized by the X-ray single crystallographic method. The complex shows a distorted square-pyramidal (4 + 1) CuN 3OCl coordination sphere. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV-Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. Complex 2 shows appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA). The complexes were subjected to in vitro cytotoxicity studies against carcinomic human alveolar basal epithelial cells (A-549) and human epithelial (HEp-2) cells. The IC 50 values of 1 and 2 are less than that of cisplatin against HEp-2 cell lines. MIC values for 1 against the bacterial strains Streptococcus mutans and Pseudomonas aeruginosa are 0.5 mM. © 2012 Elsevier Ltd. All rights reserved

STABILITY INDICATING HPLC METHOD FOR DETERMINATION OF VILAZODONE HYDROCHLORIDE

Objective: The aim and objective of this study was to develop and validate Stability Indicating HPLC method for determination of Vilazodone Hydrochloride.Methods: The method was carried out on a Phenomenex, C18 (250x4.6 mm, 5 µm) Column using a mixture of Acetonitrile: Water (50:50v/v), pH adjusted to 3.3 with Glacial Acetic Acid for separation. The flow rate was adjusted at 1 ml/min and Detection was carried out at 240 nm.Results: The retention time of vilazodone hydrochloride was found to be 2.3 min. The calibration curve was found to be linear in the range 25-75µg/ml with a correlation coefficient (R2=0.996). The limit of detection and limit of quantitation were found to be 4.78µg/ml and 14.48µg/ml respectively. The % recovery of vilazodone hydrochloride was found to be in the range of 98.21±0.08 % to 99.07±0.64%. The proposed method was successfully applied for the estimation of vilazodone hydrochloride in marketed tablet formulation.Vilazodone Hydrochloride was subjected to forced degradation under Acidic, Alkaline, Oxidation, Dry Heat and Photolytic degradation conditions. Vilazodone hydrochloride showed 3.12% degradation under acidic condition, 4.78% under alkaline condition, 7.8% under oxidation condition, 3.53% under dry heat condition and 4.9% under photolytic condition.Acid degradation impurity was identified and characterised by LC-MS/MS was found to be 1-(4-Penten-1-yl) piperazine having molecular weight 154.253 (m/z 155.08) and Molecular Formula C9H18N2.Conclusion: A simple, precise, rapid and accurate Stability Indicating HPLC method has been developed and validated for the determination of Vilazodone Hydrochloride in presence of its degradation products as per the ICH Guidelines.Â

Management of Root Knot Nematode on Tomato Through Grafting Root Stock of Solanum Sisymbriifolium

The root-knot nematodes (Meloidogyne spp) are difficult to manage once established in the field because of their wide host range, and soil-borne nature. Thus, the aim of the present study was to examine the use of resistant root stock of wild brinjal (Solanum sisymbriifolium) to reduce the loss caused by the nematodes on tomato. For the management of root-knot nematodes, grafted plant with resistant root stock of the wild brinjal was tested under farmers\u27 field conditions at Hemza of Kaski district. Grafted and non-grafted plants were produced in root-knot nematode-free soil. Around three week-old grafted and non-grafted tomato plants were transplanted in four different plastic tunnels where root-knot nematodes had been reported previously. The plants were planted in diagonal position to each other as a pair plot in 80 × 60 cm2 spacing in an average of 20 × 7 m2 plastic tunnels. Galling Index (GI) was recorded three times in five randomly selected plants in each plot at 60 days intervals. The first observation was recorded two months after transplanting. Total fruit yield was recorded from same plants. In the grafted plants, the root system was totally free from gall whereas in an average of 7.5 GI in 0-10 scale was recorded in the non-grafted plants. Fruits were harvested from time to time and cumulated after final harvest to calculate the total fruit yield. It was estimated that on an average tomato fruit yield was significantly (P>0.05) increased by 37 percent in the grafted plants compared with the non-grafted plants. Grafting technology could be used effectively for cultivation of commonly grown varieties, which are susceptible to root-knot nematodes in disease prone areas. This can be used as an alternative technology for reducing the use of hazardous pesticides for enhancing commercial organic tomato production.Journal of Nepal Agricultural Research Council Vol.3 2017: 27-3