57 research outputs found
Organotin(IV) Derivatives of L-Cysteine and their in vitro Anti-Tumor Properties
The synthesis and characterization of the organotin compounds [(n-C4H9)2Sn(cys)] (1), [(C6H5)2Sn(cys)]
(2), [(C6H5)3Sn(Hcys).(H2o)] (3), {[(CH3)2Sn(Kcys)2].2(H20)} (4), {[(n-C4H9)2Sn(Kcys)2].2(H20)} (5) and
{[(C6H5)2Sn(Kcys)2].2(H20)} (6) (where H2cys = L-cysteine) are reported. The compounds have been
characterized by elemental analysis and 1H-NMR, Uv-Vis, FT-IR and MOssbauer spectroscopic techniques.
Attempted recrystallization of (2) in DMSO/methanol 2:1 solution yielded after several days unexpectedly
the dimeric compound bis(tri-phenyltin)sulphide {[(C6H5)3Sn]2S} (7) which has been characterized by x-ray
analysis. The structure of the parent complex (2) as well as the mechanism of the decomposition of cysteine
are being further investigated. The in vitro anticancer activity of complexes (I)- (6), against human
leukemia (HL60), human liver (Bel7402), human stomach (BGC823) and human cervix epithelial human
carcinoma (Hela), nasopharyngeal carcinoma (KB) and lung cancer (PG) tumor cells, were evaluated
Evidence for nitrogen gas surface doping of the BiSe topological insulator
Using scanning tunneling spectroscopy we have studied the effects of nitrogen
gas exposure on the bismuth selenide density of states. We observe a shift in
the Dirac point which is qualitatively consistent with theoretical modeling of
nitrogen binding to selenium vacancies. In carefully controlled measurements,
BiSe crystals were initially cleaved in a helium gas environment and
then exposed to a 22 SCFH flow of ultra-high purity N gas. We observe a
resulting change in the spectral curves, with the exposure effect saturating
after approximately 50 minutes, ultimately bringing the Dirac point about 50
meV closer to the Fermi level. These results are compared to density functional
theoretical calculations, which support a picture of molecules
physisorbing near Se vacancies and dissociating into individual N atoms which
then bind strongly to Se vacancies. In this interpretation, the binding of the
N atom to a Se vacancy site removes the surface defect state created by the
vacancy and changes the position of the Fermi energy with respect to the Dirac
point.Comment: 9 pages, 3 figure
Discovery of a new generation of angiotensin receptor blocking drugs:Receptor mechanisms and in silico binding to enzymes relevant to SARS-CoV-2
The discovery and facile synthesis of a new class of sartan-like arterial antihypertensive drugs (angiotensin receptor blockers [ARBs]), subsequently referred to as “bisartans” is reported. In vivo results and complementary molecular modelling presented in this communication indicate bisartans may be beneficial for the treatment of not only heart disease, diabetes, renal dysfunction, and related illnesses, but possibly COVID-19. Bisartans are novel bis-alkylated imidazole sartan derivatives bearing dual symmetric anionic biphenyl tetrazole moieties. In silico docking and molecular dynamics studies revealed bisartans exhibited higher binding affinities for the ACE2/spike protein complex (PDB 6LZG) compared to all other known sartans. They also underwent stable docking to the Zn2+ domain of the ACE2 catalytic site as well as the critical interfacial region between ACE2 and the SARS-CoV-2 receptor binding domain. Additionally, semi-stable docking of bisartans at the arginine-rich furin-cleavage site of the SARS-CoV-2 spike protein (residues 681–686) required for virus entry into host cells, suggest bisartans may inhibit furin action thereby retarding viral entry into host cells. Bisartan tetrazole groups surpass nitrile, the pharmacophoric “warhead” of PF-07321332, in its ability to disrupt the cysteine charge relay system of 3CLpro. However, despite the apparent targeting of multifunctional sites, bisartans do not inhibit SARS-CoV-2 infection in bioassays as effectively as PF-07321332 (Paxlovid)
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