Anti-Psoriatic Effects of Antimony Compounds In Vitro

Psoriasis is a chronic inflammatory skin disease characterized by hyperproliferation of keratinocytes and a pro-inflammatory milieu in the skin. While patients with moderate to severe psoriasis are treated using targeted therapies (small molecules and monoclonal antibodies), patients suffering from milder forms are still in need of effective topical products without adverse effects. Antimony compounds (ACs) are regularly used as anti-inflammatory compounds in traditional and anthroposophic medicine and as antiprotozoan drugs. Here, we examined the effect of metallic antimony, natural antimony(III) sulfide and potassium antimonyl(III) tartrate in vitro on psoriasis-like keratinocytes and the human dendritic cell line THP-1 using qPCR, immunocytochemistry, ELISA and flow cytometry. In psoriatic keratinocytes, ACs inhibited the overexpression of the antimicrobial peptide β-defensin 2 and glucose transporter 1, as well as the hyperproliferation marker keratin 17. Furthermore, ACs mediated anti-inflammatory effects by reducing nuclear translocation of the p65 subunit of NF-κB and pSTAT3 and inhibited pro-inflammatory cytokine secretion by keratinocytes. In addition, ACs displayed anti-psoriatic effects by reducing the activation of IFN-α-treated THP-1 cells as well as the expression of the psoriasis-promoting master cytokine IL-23 by these cells. While all ACs showed anti-psoriatic effects, the most prominent results were seen with potassium antimonyl(III) tartrate. In summary, ACs display numerous anti-psoriatic effects in vitro at subtoxic concentrations. We conclude that ACs are interesting compounds for the topical treatment of psoriasis that warrant further investigation in clinical studies.     

Flameless Atomic Absorption Determination of Volatile Hydrides Using Cold Trap Collection

Abstract

The hydrides of arsenic, antimony, bismuth, and selenium are collected in a liquid nitrogen cold trap and then volatilized into either an argon-entrained air-hydrogen flame or into a Perkin-Elmer HGA-2000 Graphite Furnace for atomic absorption measurement. Flameless atomization results in approximately ten-fold lower detection limits. The sensitivities and detection limits in nanograms are, respectively, 1.0 and 0.2 for arsenic, 5.6 and 1 for antimony, 2.0 and 1 for bismuth, and 40 and 10 for selenium.     

The Rb7Bi3−3xSb3xCl16 Family: A Fully Inorganic Solid Solution with Room‐Temperature Luminescent Members

Low‐dimensional ns²‐metal halide compounds have received immense attention for applications in solid‐state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb²⁺ or unstable Sn²⁺, and a stable inorganic luminescent material has yet to be found. Here, the zero‐dimensional Rb₇Sb₃Cl₁₆ phase, comprised of isolated [SbCl₆]^3? octahedra and edge‐sharing [Sb₂Cl₁₀]^4? dimers, shows room‐temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature‐dependent PL lifetime rivals that of previous low‐dimensional materials with a specific temperature sensitivity above 0.06 K^?1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi³⁺ in the Rb₇Bi_3?3xSb_3xCl₁₆ (x≤1) family, we present the edge‐shared [Sb₂Cl₁₀]^4? dimer as a design principle for Sb‐based luminescent materials.     

Metal‐Free Stabilization of Monomeric Antimony(I): A Carbene‐Supported Stibinidene

A diamidocarbene was coordinated to an antimony(III) dichloride Lewis acid. Subsequent reduction with magnesium gave a monomeric, formally antimony(I) fragment that is supported by the diamidocarbene. Spectroscopic, crystallographic, and computational analyses demonstrated that the carbene ligand engages the antimony(I) center in π‐backbonding resulting in a short (2.068(7) Å) Sb?C interaction that is comparable to those observed in known stibaalkenes.     

Air Gap Microcell for Scanning Electrochemical Microscopic Imaging of Carbon Dioxide Output. Model Calculation and Gas Phase SECM Measurements for Estimation of Carbon Dioxide Producing Activity of Microbial Sources

Most of SECM studies have been carried out in liquid or gel phases. A Severinghaus type, CO₂ detecting potentiometric tip has been fabricated and used in gas phase SECM studies. The microcell tip is made without gas permeable membrane. Faster response, needed in SECM, was achieved by substituting the membrane with an air gap. The carbon dioxide concentration profile in the gas phase over a disc‐shaped colony of yeast has been detected with the new tip. Estimation of the carbon dioxide output of the fungi colony was attempted by fitting simulated curves to measured ones obtained with one dimensional (line) scans.     

Synthesis of a Molecule with Four Different Adjacent Pnictogens

The synthesis of a molecule containing four adjacent different pnictogens was attempted by conversion of a Group 15 allyl analogue anion [Mes*NAsPMes*]^? (Mes*=2,4,6‐tri‐tert‐butylphenyl) with antimony(III) chloride. A suitable precursor is Mes*N(H)AsPMes* ( 1 ) for which several syntheses were investigated. The anions afforded by deprotonation of Mes*N(H)AsPMes* were found to be labile and, therefore, salts could not be isolated. However, the in situ generated anions could be quenched with SbCl₃, yielding Mes*N(SbCl₂)AsPMes* ( 4 ).     

A Convenient Route to Mixed Pnictogenylboranes

We report on the synthesis and characterization of mixed pnictogenylboranes. The substitution of the Lewis base SMe₂ in (OC)₅W–PH₂BH₂–SMe₂ ( 2 ) by different pnictogenylboranes ER₂BH₂–LB (E=P, As, Sb) leads to the Lewis acid/base stabilized butane analogue (OC)₅W–PH₂BH₂ER₂BH₂–LB ( 3 a , b : E=P; R=H, SiMe₃; LB=NMe₃; 4 a , b : E=As; R=H, SiMe₃; LB=NMe₃; 5 : E=Sb; R=SiMe₃; LB=NHC^Me). All of these compounds were characterized by single‐crystal X‐ray structure analysis, mass spectrometry, NMR, and IR spectroscopy. In addition, the very unstable phosphanylborane chain PH₂BH₂PH₂BH₂–NMe₃ ( 1 ) was synthesized. DFT calculations provide insight into the thermodynamics of these reactions.