We give the complete description of bijective real-linear transformations on B(H), the algebra of all bounded linear operators on an infinite-dimensional complex Hilbert space H, where every unitary ...U∈B(H) is mapped to a unitary ϕ(U). In turn, bijective real-linear maps on B(H) preserving equivalence by unitaries will be determined.
A note on equivalence preserving maps Petek, Tatjana; Radić, Gordana
Linear & multilinear algebra,
11/1/2020, 2020-11-01, 20201101, Letnik:
68, Številka:
11
Journal Article
Recenzirano
Let
be the algebra of all bounded linear operators on complex Banach space
and let the relation
,
, denote B=TAS for some invertible
. We will give a complete description of surjective maps on
such ...that
if and only if
, for every
.
S-isoalkyl derivatives of thiosalicylic acid (isopropyl-(L1), isobutyl-(L2) and isoamyl-(L3)) were selected in order to investigate the binding interaction with the human serum albumin (HSA) using ...different spectroscopic methods and molecular docking simulation. Association constants and number of binding sites were used to analyze the quenching mechanism. The experimental results showed that the fluorescence quenching of HSA by L1, L2 and L3 occurs because of static quenching and that binding processes were spontaneous, with the leading forces in bonding by hydrogen bonding, hydrophobic interactions, and electrostatic interactions. Fluorescence spectroscopy, UV-Vis spectroscopy and synchronous fluorescence spectroscopy showed that ligands (L1, L2 and L3) can bind to HSA and that the binding of ligands induced some microenvironmental and conformational changes in HSA. The calculated distance between the donor and the acceptor according to fiFörster's theory confirms the energy transfer efficiency between the acceptor and HSA. Results of site marker competitive experiments showed that the tested compounds bind to HSA in domain IIA (Site I). Molecular dynamics and docking calculations demonstrated that L3 binds to the Sudlow site I of HSA with lower values of binding energies compared to L1 and L2, indicating the formation of the most stable ligand-HSA complex. Understanding the binding mechanisms of S-isoalkyl derivatives of the thiosalicylic acid to HSA may provide valuable data for the future studies of their biological activity and application as potential antitumor drugs.Communicated by Ramaswamy H. Sarma.
A series of complexes of platinum(IV) (
C1
–
C5
) and zinc(II) (
C6
–
C10
) with S-alkyl derivatives of thiosalicylic acid were prepared and characterized. The interactions of the complexes with calf ...thymus DNA were analyzed by absorption (UV–Vis) and emission spectral studies (ethidium bromide displacement studies). The cytotoxic activities of complexes
C1
–
C10
were determined against mouse B cell lymphocytic leukemia cells (BCL1), human B-prolymphocytic leukemia (JVM-13), mouse mammary carcinoma cells (4T1), and human mammary carcinoma cells (MDA-MB-468) and compared to the activities of the free ligand precursors and cisplatin. The cytotoxicities of the platinum(IV) and zinc(II) complexes toward mouse tumor cell lines were higher compared with their effects on human tumor cell lines. The zinc(II) complex
C9
showed the highest antitumor activity toward the tested human cell lines, while the platinum(IV) complex C4 exhibited the highest antitumor activity toward mouse BCL1 and 4T1 cells. Both
C4
and
C9
have ligands derived from S-propyl thiosalicylic acid.
The numerous side effects of platinum based chemotherapy has led to the design of new therapeutics with platinum replaced by another transition metal. Here, we investigated the interactions of ...previously reported copper(II) complexes containing S-isoalkyl derivatives, the salicylic acid with guanosine-5'-monophosphate and calf thymus DNA (CT-DNA) and their antitumor effects, in a colon carcinoma model. All three copper(II) complexes exhibited an affinity for binding to CT-DNA, but there was no indication of intercalation or the displacement of ethidium bromide. Molecular docking studies revealed a significant affinity of the complexes for binding to the minor groove of B-form DNA, which coincided with DNA elongation, and a higher affinity for binding to Z-form DNA, supporting the hypothesis that the complex binding to CT-DNA induces a local transition from B-form to Z-form DNA. These complexes show a moderate, but selective cytotoxic effect toward colon cancer cells in vitro. Binuclear complex of copper(II) with S-isoamyl derivative of thiosalicylic acid showed the highest cytotoxic effect, arrested tumor cells in the G2/M phase of the cell cycle, and significantly reduced the expression of inflammatory molecules pro-IL-1β, TNF-α, ICAM-1, and VCAM-1 in the tissue of primary heterotopic murine colon cancer, which was accompanied by a significantly reduced tumor growth and metastases in the lung and liver.
Four new complexes of copper(II) with S,O-tetradentate ligands, derivatives of thiosalicylic acid, encompassing an ethylene-, propylene-, butylene- and pentylene- bridge, were synthesized and ...characterized by microanalysis, molecular conductance and infrared (IR) spectra. The structures were assumed based on the previously mentioned analyses and confirmed with the results of electron paramagnetic resonance (EPR) spectra. The reactivity of complexes towards L-methionine (L-Met), L-cysteine (L-Cys) and guanosine-5′-monophosphate (5’-GMP) was also examined. Complex C1 (Cu(S,O-ethylene-thiosalicylic acid)(H2O)2) containing two inert methylene groups in the side chain of ligand shows the highest reactivity, while the least reactive is complex C4 (Cu(S,O-pentylene-thiosalicylic acid)(H2O)2) with five methylene groups. All complexes showed the highest reactivity towards L-Met and the lowest reactivity towards 5’-GMP. The interactions of complexes C1-C4 with calf thymus DNA (ct-DNA) were examined by ultraviolet-visible (UV–Vis) absorption and fluorescence spectral studies, revealing good DNA interaction abilities. All synthesized complexes C1-C4 show to interact with human serum albumin (HSA) with high values of binding constants. Complexes interaction with DNA/HSA was also confirmed using molecular docking simulations. All synthesized complexes reduce viability of human colon, breast and lung cancer cells, evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric technique. The complex Cu(S,O-pentylene- thiosalicylic acid)(H2O)2 showed the highest binding affinity constants to DNA/HSA and highest cytotoxicity, thus presenting a good candidate for further pharmacological research in the field of colon, breast and lung cancer therapy.
The complexes of copper(II) with S,O-derivatives of thiosalicylic acid (C1-C4) were synthesized and characterized. All synthesized complexes exhibit the interaction with human serum albumin and calf thymus-DNA, and cytotoxicity confirmed by molecular docking and in vitro studies, while the highest activity showed complex C4 Cu(S,O-pentylene-thiosalicylic acid)(H2O)2. Display omitted
•Synthesis of S,O-ligands, derivatives of thiosalicylic acid and Cu(II)-complexes.•Characterization of S,O-ligands and corresponding Cu(II)-complexes.•Kinetic measurements and DNA interactions of synthesized complexes.•Molecular docking studies.•Antitumor activity of Cu(II)-complexes.
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•Structural features of the copper(II), zinc(II) and cobalt(II)-quinolone complexes are presented and discussed.•Antimicrobial and antitumor activity of the selected coordination ...compounds is assessed.•Binding affinity of selected coordination compounds to calf-thymus DNA, bovine and human serum albumins are investigated.
Bioessential metal complexes with quinolone antibiotics as ligands attract wide attention in bioinorganic chemistry due to their greater biological potential that may lead to the synthesis of novel coordination compounds with enhanced pharmacological activity. In this review structural features of copper(II), zinc(II) and cobalt(II)-quinolone complexes are presented and discussed in detail. Antimicrobial and antitumor activity as well as the binding affinity of selected coordination compounds to calf-thymus DNA, bovine and human serum albumins are also investigated. Further perspectives related to the choice of the metal ion, quinolone ligand and various co-ligands are also discussed to clarify and predict the main factors that contribute to biological activity of the bioessential metal complexes.
Isoalkyl (isoalkyl = isopropyl-(L1), isobutyl-(L2) and isoamyl-(L3)) derivatives of thiosalicylic acid (TSA) were prepared by alkylation of TSA with corresponding isoalkyl-chlorides in the alkaline ...water-ethanol solution. The new free copper(II)-complexes with corresponding S-isoalkyl derivatives of TSA (C1-copper(II)-complex with S-isopropyl derivative of thiosalicylic acid, C2-copper(II)-complex with S-isobutyl derivative of thiosalicylic acid and C3-copper(II)-complex with S-isoamyl derivative of thiosalicylic acid) have been synthesized by direct reaction of copper(II)-nitrate with ligand precursor and then characterized by microanalysis, infrared spectra (IR) and EPR (electron paramagnetic resonance) spectra. The spectroscopically predicted structure of the obtained binuclear copper(II)-complex with S-isopropyl derivative of thiosalicylic acid was confirmed by X-ray analysis. Single crystals suitable for X-ray measurements were obtained by slow crystallization from a water solution. Newly synthesized precursors S-isoalkyl derivatives of thiosalicylic acid and corresponding copper(II)-complexes moderately reduced viability of human and murine lung cancer cells, they showed similar cytotoxic effect on human colorectal cancer cells as cisplatin and lower cytotoxic effect than cisplatin toward normal fibroblasts, evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) colorimetric technique. All new complexes exhibited apoptotic effect toward lung cancer cells, stronger than cisplatin, whereas only C3 induced significant apoptosis of colorectal cancer cells. Complex C1 showed significant antiproliferative effect against murine lung cancer cells, LLC1, while C2 reduced expression of Ki67 in human colorectal cancer cells. All tested complexes induced cell cycle arrest of HCT116 cells in G2/M phase.
The complexes have been obtained by direct reaction of copper(II)-nitrate trihydrate with derivatives of S-isoalkyl thiosalicylic acid. The spectroscopically predicted structure of the obtained binuclear copper(II)-complex was confirmed by X-ray analysis. Copper(II)-complexes exerted cytotoxic, antiproliferative, apoptotic effects and disturbed cell cycle distribution of murine lung carcinoma cells. Display omitted
•Synthesis of copper(II)-complexes with derivatives of S-isoalkyl thiosalicylic acid•Crystal structure of Cu2(S-isoalkyl-thiosal)4(H2O)2·2H2O•Biological activity of copper(II)-complexes
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•New ligands and corresponding palladium(II) complexes were synthesized.•Characterization was performed by IR, 1H and 13C NMR spectroscopy.•The interactions of new complexes with ...CT-DNA and HSA were investigated.•In vitro cytotoxic activity of these ligands and complexes were evaluated.•Antimicrobial activity of ligands and complexes were investigated.
In this paper, we presented synthesis, characterization, HSA/DNA binding evaluation, in vitro cytotoxic activity and in vitro antimicrobial activity of three new ligands of general formula. R2-S,S-pddmb (L1-L3) and their corresponding palladium(II) complexes of general formula PdCl2(R2-S,S-pddmb) (R = n-propyl, n-butyl, n-pentyl; S,S-pddmb = (S,S)-propylenediamine-N,N'-di-2-(3-methyl)-butanoate). Ligands and complexes were characterized by elemental microanalysis, infrared, 1H and 13C NMR spectroscopy. The interactions of new palladium(II) complexes with human serum albumin (HSA) and calf thymus DNA (CT-DNA) were investigated using UV–Vis absorption and fluorescence spectroscopy. The high values of the binding constant, Kb, and the Stern-Volmer quenching constant, KSV, are the result of good binding of all complexes to HSA and CT-DNA. In vitro cytotoxic activity of these ligands and complexes was evaluated against four tumor cell lines, 4 T1, CT26, MDA-MD-468, HCT116 and mesenchymal stem cells (mMSC). C3 complex showed high cytotoxic activity against MDA-MD-468 cell line. Flow cytometry analysis showed that L3 ligand and the corresponding complex (C3) stimulated apoptosis of tumor cells via inhibition of expression of antiapoptotic Bcl-2 molecule. L3 ligand and C3 complex slowed down cell proliferation and arrested tumor cell in the G0/G1 phase by decreasing Cyclin-D expression and by increasing expression of P21. In vitro antimicrobial activity of ligands and complexes was also investigated. The testing was performed by microdilution method and minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined. The testing was conducted against 12 microorganisms. The tested ligands and palladium(II) complexes showed selective and moderate activity.
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