5 research outputs found
Role of Group 12 Metals in the Reduction of H<sub>2</sub>O<sub>2</sub> by Santi’s Reagent: A Computational Mechanistic Investigation
PhSeZnCl, which is also known as Santi’s reagent,
can catalyze
the reduction of hydrogen peroxide by thiols with a GPx-like mechanism.
In this work, the first step of this catalytic cycle, i.e., the reduction
of H2O2 by PhSeZnCl, is investigated in silico using state-of-the-art density functional theory
calculations. Then, the role of the metal is evaluated by replacing
Zn with its group 12 siblings (Cd and Hg). The thermodynamic and kinetic
factors favoring Zn are elucidated. Furthermore, the role of the halogen
is considered by replacing Cl with Br in all three metal compounds,
and this turns out to be negligible. Finally, the overall GPx-like
mechanism of PhSeZnCl and PhSeZnBr is discussed by evaluating the
energetics of the mechanistic path leading to the disulfide product
Agarsenone, a Cadinane Sesquiterpenoid from <i>Commiphora erythraea</i>
Agarsenone (<b>1</b>), a new
cadinane sesquiterpenoid, was
isolated from the resin of <i>Commiphora erythraea.</i> The
structures of <b>1</b> and
its decomposition products agarsenolides (<b>2a</b> and <b>2b</b>) and myrrhone (<b>3</b>) were established by extensive
NMR spectroscopic analysis. The absolute configuration of <b>3</b> and the relative and absolute configurations of <b>1</b> were
assigned by comparison of experimental and calculated optical rotatory
dispersion and electronic circular dichroism spectra
Catalytic Chalcogenylation under Greener Conditions: A Solvent-Free Sulfur- and Seleno-functionalization of Olefins via I<sub>2</sub>/DMSO Oxidant System
Herein, we report a solvent- and
metal-free methodology for the
alkoxy-chalcogenylation of styrenes, using molecular iodine as a catalyst,
DMSO as a stoichiometric oxidant, and different nucleophiles under
microwave irradiation. This eco-friendly approach afforded the desired
products in good to excellent yields in only 10 min. In addition,
using the same protocol, we carried out the cyclization reaction of
relevant molecules, such as lapachol derivatives
Design and Synthesis of DiselenoBisBenzamides (DISeBAs) as Nucleocapsid Protein 7 (NCp7) Inhibitors with anti-HIV Activity
The
interest in the synthesis of Se-containing compounds is growing with
the discovery of derivatives exhibiting various biological activities.
In this manuscript, we have identified a series of 2,2′-diselenobisbenzamides
(DISeBAs) as novel HIV retroviral nucleocapsid protein 7 (NCp7) inhibitors.
Because of its pleiotropic functions in the whole viral life cycle
and its mutation intolerant nature, NCp7 represents a target of great
interest which is not reached by any anti-HIV agent in clinical use.
Using the diselenobisbenzoic scaffold, amino acid, and benzenesulfonamide
derivatives were prepared and biologically profiled against different
models of HIV infection. The incorporation of amino acids such as
glycine and glutamate into DISeBAs <b>7</b> and <b>8</b> resulted in selective anti-HIV activity against both acutely and
chronically infected cells as well as an interesting virucidal effect.
DISeBAs demonstrated broad antiretroviral activity, encompassing HIV-1
drug-resistant strains including clinical isolates, as well as simian
immunodeficiency virus (SIV). Time of addition experiments, along
with the observed dose dependent inhibition of the Gag precursor proper
processing, confirmed that their mechanism of action is based on NCp7
inhibition
Induction of reactive oxygen species by diphenyl diselenide is preceded by changes in cell morphology and permeability in <i>Saccharomyces cerevisiae</i>
<p>Organoselenium compounds, such as diphenyl diselenide (PhSe)<sub>2</sub> and phenylselenium zinc chloride (PhSeZnCl), show protective activities related to their thiol peroxidase activity. However, depending on experimental conditions, organoselenium compounds can cause toxicity by oxidising thiol groups of proteins and induce the production of reactive oxygen species (ROS). Here, we analysed the toxicity of (PhSe)<sub>2</sub> and PhSeZnCl in yeast <i>Saccharomyces cerevisiae</i>. Cell growth of <i>S. cerevisiae</i> after 1, 2, 3, 4, 6, and 16 h of treatment with 2, 4, 6, and 10 μM of (PhSe)<sub>2</sub> was evaluated. For comparative purpose, PhSeZnCl was analysed only at 16 h of incubation at equivalent concentrations of selenium (i.e. 4, 8, 12, and 20 μM). ROS production (DCFH-DA), size, granularity, and cell membrane permeability (propidium iodide) were determined by flow cytometry. (PhSe)<sub>2</sub> inhibited cell growth at 2 h (10 μM) of incubation, followed by increase in cell size. The increase of cell membrane permeability and granularity (10 μM) was observed after 3 h of incubation, however, ROS production occurs only at 16 h of incubation (10 μM) with (PhSe)<sub>2</sub>, indicating that ROS overproduction is a more likely consequence of (PhSe)<sub>2</sub> toxicity and not its determinant. All tested parameters showed that only concentration of 20 μM induced toxicity in samples incubated with PhSeZnCl. In summary, the results suggest that (PhSe)<sub>2</sub> toxicity in <i>S. cerevisiae</i> is time and concentration dependent, presenting more toxicity when compared with PhSeZnCl.</p