The synthesis of cis and trans geometrical isomers of platinum( ii ) complexes with a symmetric N-heterocyclic carbene ligand ( Me NHC) is reported. These complexes were obtained from ...1,3-dimethylimidazolium-2-carboxylate, a masked NHC precursor. Their cytotoxicity, oxidative nature, and antibacterial behavior were investigated. The highest cytotoxic effect (IC 50 = 1.21 μM) was observed with the cis -Pt( Me NHC) 2 Cl 2 complex in the cervix cancerous cell line HeLa.
In the therapy of cancer, several treatments have been designed using nanomaterials, among which gold nanoparticles (AuNPs) have been featured as a promising antitumoral agent. Our research group has ...developed the synthesis of gold nanoparticles L-AuNPs and D-AuNPs stabilized with zwitterions of imidazolium (L-1 and D-1) derived from L-methionine and D-methionine. Because the stabilizer agent is chiral, we observed through circular dichroism that AuNPs also present chirality; such chirality as well as the fact that the stabilizing agent contains fragments of methionine and imidazolium that are commonly involved in biological processes, opens up the possibility that this system may have biological compatibility. Additionally, the presence of methionine in the stabilizing agent opens the application of this system as a possible antitumor agent because methionine is involved in methylation processes of molecules such as DNA.
The aim of this research is the evaluation of the antitumor activity of gold nanoparticles stabilized with zwitterions of imidazolium (L-AuNPs) derived from L-methionine in the model of BALB/c mice with lymphoma L5178Y.
Taking as a parameter cell density, the evaluation of the inhibitory effect of L-AuNPs was carried out with a series of in vivo tests in BALB/c type mice; three groups of five mice each were formed (Groups 1, 2 and 3); all mice were i.p. inoculated with the lymphoblast murine L5178Y. Group 1 consisted of mice without treatment. In the Groups 2 and 3 the mice were treated with L-AuNPs at 0.3 mg/Kg on days 1, 7 and 14 by orally and intraperitonally respectively.
These results show low antitumor activity of these gold nanoparticles (L-NPsAu) but interestingly, the imidazolium stabilizing agent of gold nanoparticle (L-1) displayed promising antitumor activity. On the other hand, the enantiomer of L-1, (D-1) as well as asymmetric imidazole derivate from L-methionine (L-2), do not exhibit the same activity as L-1.
The imidazolium stabilizing agent (L-1) displayed promising antitumor activity. Modifications in the structure of L-1 showed that, the stereochemistry (like D-1) and the presence of methionine fragments (like L-2) are determinants in the antitumor activity of this compound.
A simple and direct method is described to prepare cationic bis(NHC)-Au(i) complexes containing N-alkyl or N-aryl NHC ligands to generate relevant gold complexes using metallic gold as the starting ...material.
A family of water soluble gold(I) complexes with NHC carbene ligands derived from amino acids were prepared via the direct transmetalation reaction of the respective silver NHC complexes. The ...oxidative addition of Br2 to Au(I)-NHC complexes was studied and the crystal structure of AuBr3(NHC) compound derived from alanine is presented.
A series of Au(NHC)2 (1a–4a) complexes supported by NHC ligands derived from glycine, alanine, methionine and phenylalanine (1–4 respectively) were prepared via a direct transmetalation reaction of their respective silver complexes. The Au complexes were characterized by ESI-MS and NMR spectroscopy in solution. These compounds exhibit instability when the solvent is removed; they displayed a strong tendency to form colored solutions in the order 4a>3a>2a>1a, which is associated with gold nanoparticles. 1a and 2a undergo oxidative addition of elemental bromine, yielding Au(NHC)2Br2 (1b) for 1a and a mixture of Au(NHC)2Br2 (2b) and Au(NHC)Br3 (2c) for 2a. 2b and 2c were characterized by single crystal X-ray diffraction.
The synthesis of
cis
and
trans
geometrical isomers of platinum(
ii
) complexes with a symmetric N-heterocyclic carbene ligand (
Me
NHC) is reported. These complexes were obtained from ...1,3-dimethylimidazolium-2-carboxylate, a masked NHC precursor. Their cytotoxicity, oxidative nature, and antibacterial behavior were investigated. The highest cytotoxic effect (IC
50
= 1.21 μM) was observed with the
cis
-Pt(
Me
NHC)
2
Cl
2
complex in the cervix cancerous cell line HeLa.
Cis
- and
trans
-NHC-Pt(
ii
) isomers from the masked carbene 1,3-dimethylimidazolium-2-carboxylate: the relevance of isomerism in the biological activity.
A simple and direct method is described to prepare cationic bis(NHC)-Au(
i
) complexes containing
N
-alkyl or
N
-aryl NHC ligands to generate relevant gold complexes using metallic gold as the ...starting material.
A simple and direct method is described to prepare cationic bis(NHC)-Au(
i
) complexes using metallic gold as the starting material.
SARS-CoV-2 variants emerged in late 2020, and at least three variants of concern (B.1.1.7, B.1.351, and P1) have been reported by WHO. These variants have several substitutions in the spike protein ...that affect receptor binding; they exhibit increased transmissibility and may be associated with reduced vaccine effectiveness. In the present work, we report the identification of a potential variant of interest, harboring the mutations T478K, P681H, and T732A in the spike protein, within the newly named lineage B.1.1.519, that rapidly outcompeted the preexisting variants in Mexico and has been the dominant virus in the country during the first trimester of 2021.
The synthesis of organometallic gold complexes with symmetric N-heterocyclic carbene ligand (NHC) derivatives derived from 2-(methylthio)aniline is reported. These complexes were obtained as either ...molecular monocarbene or cationic biscarbene complex. These compounds were tested as gold nanoparticle precursors that were stabilized by the corresponding NHC ligand.
Display omitted
The synthesis of organometallic gold complexes with symmetric N-heterocyclic carbene ligand (NHC) derivatives derived from 2-(methylthio)aniline is reported. These complexes were obtained as either molecular monocarbene complexes Au(NHC)Cl, Au(NHC)Cl3, and Au(NHC)Br3) or cationic biscarbene complex Au(NHC)2PF6. These compounds were tested as gold nanoparticle precursors that were stabilized by the corresponding NHC ligand.
Gold nanoparticles (AuNPs) stabilized by imidazolium salts derived from amino acids glycine (1), rac-alanine (2), l-phenylalanine (3), and rac-methionine (4) were prepared. The AuNPs were stabilized ...the most by 4, which kept the particles dispersed in water for months at pH > 5.5. These AuNPs exhibited a well-defined absorption band at 517 nm and had an average particle size of 11.21 ± 0.07 nm. The 4-AuNPs were reversibly aggregated by controlling the pH of the solution. Chiral R,R-4-AuNPs and S,S-4-AuNPs were synthesized, and the chiral environment on the nanoparticle surface was confirmed using circular dichroism; these nanoparticles exhibited a molecular recognition of chiral substrates. Furthermore, they showed potential for separating racemic mixtures when supported on a layered double hydroxide.
Abstract Introduction Endothelial cells (ECs) are an important component of the blood coagulation system because it maintains blood fluid. Because in patients with venous thromboembolic disease (VTD) ...a thrombophilic condition is not found sometimes, we investigated if endothelial colony-forming cells (ECFCs) from these patients have biological and functional abnormalities. Patients and methods Human mononuclear cells (MNCs) were obtained from peripheral blood from patients with VTD and controls to obtain ECFCs. These cells were assayed for their immunophenotype and electron microscopy characteristics and their ability to form capillary-like structures and to produce pro-inflammatory and pro-angiogenic cytokines and reactive oxygen species (ROS). Results ECFCs appeared at 7 and 21 days of culture in VTD patients and controls, respectively. ECFCs increased 8-fold in patients and emerged 1 week earlier. No differences in the size of the colonies of ECFCs were found. Numbers and time of appearance of ECFCs was different between groups. ECFC-derived ECs (ECFC-ECs) of both groups expressed CD31, CD34, CD146, and CD-309 but none expressed CD45, CD14, or CD90. Interest CD34 was highly expressed in ECFC-ECs from patients. In both groups, ECFC-ECs showed similar capacity to form capillary-like structures but ECFC-ECs from patients had significant abnormalities in the mitochondrial membrane. We found a significant increase in ROS production in ECFC-ECs from patients. There were significant differences in cytokine profiles between VTD patients and controls. Conclusions We found a dysfunctional state in ECFC from VTD patients resembling some characteristics of dysfunctional ECs. These findings may help to understand some pathophysiological aspects of VTD.
PDF
