Diphenyl diselenide protects against glycerol-induced renal damage in rats

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Catalytic Antioxidants in the Kidney

Reactive oxygen species and reactive nitrogen species are highly implicated in kidney injuries that include acute kidney injury, chronic kidney disease, hypertensive nephropathy, and diabetic nephropathy. Therefore, antioxidant agents are promising therapeutic strategies for kidney diseases. Catalytic antioxidants are defined as small molecular mimics of antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, and some of them function as potent detoxifiers of lipid peroxides and peroxynitrite. Several catalytic antioxidants have been demonstrated to be effective in a variety of in vitro and in vivo disease models that are associated with oxidative stress, including kidney diseases. This review summarizes the evidence for the role of antioxidant enzymes in kidney diseases, the classifications of catalytic antioxidants, and their current applications to kidney diseases.

Investigation into the intracellular fates, speciation and mode of action of selenium-containing neuroprotective agents using XAS and XFM

BACKGROUND

A variety of selenium compounds have been observed to provide protection against oxidative stress, presumably by mimicking the mechanism of action of the glutathione peroxidases. However, the selenium chemistry that underpins the action of these compounds has not been unequivocally established.

METHODS

The synchrotron based techniques, X-ray absorption spectroscopy and X-ray fluorescence microscopy were used to examine the cellular speciation and distribution of selenium in SH-SY5Y cells pretreated with one of two diphenyl diselenides, or ebselen, followed by peroxide insult.

RESULTS

Bis(2-aminophenyl)diselenide was shown to protect against oxidative stress conditions which mimic ischemic strokes, while its nitro analogue, bis(2-nitrophenyl)diselenide did not. This protective activity was tentatively assigned to the reductive cleavage of bis(2-aminophenyl)diselenide inside human neurocarcinoma cells, SH-SY5Y, while bis(2-nitrophenyl)diselenide remained largely unchanged. The distinct chemistries of the related compounds were traced by the changes in selenium speciation in bulk pellets of treated SH-SY5Y cells detected by X-ray absorption spectroscopy. Further, bis(2-aminophenyl)diselenide, like the known stroke mitigation agent ebselen, was observed by X-ray fluorescence imaging to penetrate into the nucleus of SH-SY5Y cells while bis(2-nitrophenyl)diselenide was observed to be excluded from the nuclear region.

CONCLUSIONS

The differences in activity were thus attributed to the varied speciation and cellular localisation of the compounds, or their metabolites, as detected by X-ray absorption spectroscopy and X-ray fluorescence microscopy.

SIGNIFICANCE

The work is significant as it links, for the first time, the protective action of selenium compounds against redox stress with particular chemical speciation using a direct measurement approach.

Selenides and Diselenides: A Review of Their Anticancer and Chemopreventive Activity

Selenium and selenocompounds have attracted the attention and the efforts of scientists worldwide due to their promising potential applications in cancer prevention and/or treatment. Different organic selenocompounds, with diverse functional groups that contain selenium, have been reported to exhibit anticancer and/or chemopreventive activity. Among them, selenocyanates, selenoureas, selenoesters, selenium-containing heterocycles, selenium nanoparticles, selenides and diselenides have been considered in the search for efficiency in prevention and treatment of cancer and other related diseases. In this review, we focus our attention on the potential applications of selenides and diselenides in cancer prevention and treatment that have been reported so far. The around 80 selenides and diselenides selected herein as representative compounds include promising antioxidant, prooxidant, redox-modulating, chemopreventive, anticancer, cytotoxic and radioprotective compounds, among other activities. The aim of this work is to highlight the possibilities that these novel organic selenocompounds can offer in an effort to contribute to inspire medicinal chemists in their search of new promising derivatives.

Free radical scavenging in vitro and biological activity of diphenyl diselenide-loaded nanocapsules: DPDS-NCS antioxidant and toxicological effects

Selenium compounds, such as diphenyl diselenide (DPDS), have been shown to exhibit biological activity, including antioxidant effects. However, the use of DPDS in pharmacology is limited due to in vivo pro-oxidative effects. In addition, studies have shown that DPDS-loaded nanocapsules (DPDS-NCS) have greater bioavailability than free DPDS in mice. Accordingly, the aim of this study was to investigate the antioxidant properties of DPDS-NCS in vitro and biological activity in mice. Our in vitro results suggested that DPDS-NCS significantly reduced the production of reactive oxygen species and Fe(II)-induced lipid peroxidation (LPO) in brain. The administration of DPDS-NCS did not result in death or change the levels of endogenous reduced or oxidized glutathione after 72 hours of exposure. Moreover, ex vivo assays demonstrated that DPDS-NCS significantly decreased the LPO and reactive oxygen species levels in the brain. In addition, the highest dose of DPDS-NCS significantly reduced Fe(II)- and sodium nitroprusside-induced LPO in the brain and Fe(II)-induced LPO in the liver. Also, δ-aminolevulinate acid dehydratase within the brain was inhibited only in the highest dose of DPDS-NCS. In conclusion, our data demonstrated that DPDS-NCS exhibited low toxicity in mice and have significant antioxidant characteristics, indicating that nanoencapsulation is a safer method of DPDS administration.

Localized drug delivery of selenium (Se) using nanoporous anodic aluminium oxide for bone implants

Release behavior and cancer toxicity of different forms of Se loaded into nanoporous AAO were studied.

Association of oxidative stress to the genesis of anxiety: implications for possible therapeutic interventions

Oxidative stress caused by reactive species, including reactive oxygen species, reactive nitrogen species, and unbound, adventitious metal ions (e.g., iron [Fe] and copper [Cu]), is an underlying cause of various neurodegenerative diseases. These reactive species are an inevitable by-product of cellular respiration or other metabolic processes that may cause the oxidation of lipids, nucleic acids, and proteins. Oxidative stress has recently been implicated in depression and anxiety-related disorders. Furthermore, the manifestation of anxiety in numerous psychiatric disorders, such as generalized anxiety disorder, depressive disorder, panic disorder, phobia, obsessive-compulsive disorder, and posttraumatic stress disorder, highlights the importance of studying the underlying biology of these disorders to gain a better understanding of the disease and to identify common biomarkers for these disorders. Most recently, the expression of glutathione reductase 1 and glyoxalase 1, which are genes involved in antioxidative metabolism, were reported to be correlated with anxiety-related phenotypes. This review focuses on direct and indirect evidence of the potential involvement of oxidative stress in the genesis of anxiety and discusses different opinions that exist in this field. Antioxidant therapeutic strategies are also discussed, highlighting the importance of oxidative stress in the etiology, incidence, progression, and prevention of psychiatric disorders.

Selenium inhibits renal oxidation and inflammation but not acute kidney injury in an animal model of rhabdomyolysis

Acute kidney injury (AKI) is a manifestation of rhabdomyolysis (RM). Extracellular myoglobin accumulating in the kidney after RM promotes oxidative damage, which is implicated in AKI.

AIM

To test whether selenium (Se) supplementation diminishes AKI and improves renal function.

RESULTS

Dietary selenite increased Se in the renal cortex, as demonstrated by X-ray fluorescence microscopy. Experimental RM-stimulated AKI as judged by increased urinary protein/creatinine, clusterin, and kidney injury molecule-1 (KIM-1), decreased creatinine clearance (CCr), increased plasma urea, and damage to renal tubules. Concentrations of cholesterylester (hydro)peroxides and F₂-isoprostanes increased in plasma and renal tissues after RM, while aortic and renal cyclic guanidine monophosphate (cGMP; marker of nitric oxide (NO) bioavailability) decreased. Renal superoxide dismutase-1, phospho-P65, TNFα gene, MCP-1 protein, and the 3-chloro-tyrosine/tyrosine ratio (Cl-Tyr/Tyr; marker of neutrophil activation) all increased after RM. Dietary Se significantly decreased renal lipid oxidation, phospho-P65, TNFα gene expression, MCP-1 and Cl-Tyr/Tyr, improved NO bioavailability in aorta but not in the renal microvasculature, and inhibited proteinuria. However, CCr, plasma urea and creatinine, urinary clusterin, and histopathological assessment of AKI remained unchanged. Except for the Se++ group, renal angiotensin-receptor-1/2 gene/protein expression increased after RM with parallel increases in MEK1/2 inhibitor-sensitive MAPkinase (ERK) activity.

INNOVATION

We employed synchrotron radiation to identify Se distribution in kidneys, in addition to assessing reno-protection after RM.

CONCLUSION

Se treatment has some potential as a therapeutic for AKI as it inhibits oxidative damage and inflammation and decreases proteinuria, albeit histopathological changes to the kidney and some plasma and urinary markers of AKI remain unaffected after RM.

Diphenyl diselenide attenuates hepatic and hematologic toxicity induced by chlorpyrifos acute exposure in rats

PURPOSE

In this study, we investigated the effect of diphenyl diselenide [(PhSe)(2)] on chlorpyrifos (CPF)-induced hepatic and hematologic toxicity in rats.

METHODS

Rats were pre-treated with (PhSe)(2) (5 mg/kg) via the oral route (oral gavage) once a day for 7 days. On the eighth and ninth days, rats were treated with (PhSe)(2) (5 mg/kg) 30 min prior to CPF (50 mg/kg, by subcutaneous route). The aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities were determined in plasma of rats. Lipid peroxidation, protein carbonyl, and non-protein thiol levels as well as catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and gluthatione S-transferase activities were determined in livers of rats. Hematological parameters were also determined.

RESULTS

The results showed that CPF caused hepatic oxidative damage, as demonstrated by an increase in lipid peroxidation and protein carbonyl levels which was associated with a decrease in antioxidant defenses. CPF exposure caused a reduction in the leukocyte, indicating hematologic toxicity. (PhSe)(2) was effective in attenuating these toxic effects caused by CPF exposure in rats.

CONCLUSIONS

The results indicated that (PhSe)(2) was effective in protecting the hepatic and hematologic toxicity induced by acute CPF exposure in rats.

Reduction of acute hepatic damage induced by acetaminophen after treatment with diphenyl diselenide in mice

In this study, the authors evaluated the ability of diphenyl diselenide (PhSe)(2) to reverse acute hepatic failure induced by acetaminophen (APAP) in mice. The animals received an APAP dose of 600 mg/kg intraperitoneally (i.p.), and then 1 hour later, they received 15.6 mg/kg i.p. of (PhSe)(2). Three hours after (PhSe)(2) administration, the animals were sacrificed and blood and liver samples were collected for analysis. The serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured. The levels of reduced glutathione (GSH) and oxidized glutathione (GSSG), thiobarbituric acid-reactive substances (TBARS), 2',7'-dichlorofluorescein (DFC), catalase activity (CAT), and myeloperoxidase (MPO) activity were determined in the liver. A methyl-tetrazolium reduction (MTT) assay was also performed on the liver. Histopathological studies were conducted in all groups. Exposure of animals to APAP induced oxidative stress, increased lipid peroxidation (LPO), and the generation of reactive species, reduced the levels of GSH, and caused an increase in the MPO activity. Treatment with (PhSe)(2) reduced LPO and the formation of reactive species and inhibited the processes of inflammation, reducing the hepatic damage induced by APAP. The results of this study show that (PhSe)(2) is a promising therapeutic option for the treatment of acute hepatic failure.

Antioxidant-prooxidant properties of a new organoselenium compound library

The present study describes the biological evaluation of a library of 59 organo-selenium compounds as superoxide (O₂⁻) generators and cytotoxic agents in human prostate cancer cells (PC-3) and in breast adenocarcinoma (MCF-7). In order to corroborate that the biological activity for selenium compounds depends on the chemical form, a broad structural variety is presented. These structures include selenocyanates, diselenides, selenoalkyl functional moieties and eight newly synthesized symmetrically substituted dithioselenites and selenylureas. Eleven of the derivatives tested showed high levels of superoxide generation in vitro via oxidation of reduced glutathione (GSH) and nine of them were more catalytic than the reference compound, diselenodipropionic acid. Eighteen of the library compounds inhibited cell growth more than or similar to reference chemotherapeutic drugs in PC-3 and eleven were more potent cytotoxic agents than etoposide in the MCF-7 cell line. Considering both parameters (superoxide generation and cell cytotoxicity) compounds B1, C6 and C9 displayed the best therapeutic profiles. Considering that many diselenide compounds can generate superoxide (O₂⁻) in vitro via oxidation of GSH and other thiols, the analogue B1, that contains a diselenide moiety, was selected for a preliminary mechanistic investigation, which revealed that B1 has apoptogenic effects similar to camptothecin mediated by reactive oxygen species (ROS) in lymphocytic leukemia cells (CCRF-CEM) and affected the MCF-7 cell-cycle in G₂/M and S-phases.

Involvement of catalase in the protective effect of binaphthyl diselenide against renal damage induced by glycerol

In the present study, the protective effect of binapthyl diselenide [(NapSe)(2)] was investigated on glycerol-induced renal damage in rats. Adult male Wistar rats were treated with (NapSe)(2) (50 mg/kg, orally) or vehicle. After 24 h (NapSe)(2) treatment, the animals received an intramuscular injection of glycerol (8 ml/kg, dissolved in saline) or vehicle as a divided dose into the hind limbs. Twenty-four hours afterwards, rats were euthanized and the levels of urea and creatinine were measured in plasma. Non-protein thiol (NPSH) levels and catalase (CAT) activity were evaluated in renal homogenates. Histopathological evaluations were also performed in kidneys of rats. The rats exposed to glycerol presented swelling of the proximal and distal tubules with evidence of cell damage and death. Glycerol-exposed rats presented an increase in renal failure markers (plasmatic urea and creatinine levels) and a reduction in renal CAT activity. No change was observed in NPSH levels in kidneys of rats exposed to glycerol. (NapSe)(2) protected against the alterations caused by glycerol in rats. (NapSe)(2) increased per se NPSH levels (33%) in kidneys of rats. In conclusion, the results demonstrated that treatment with (NapSe)(2) protected against renal damage induced by glycerol in rats, probably due to its antioxidant effect.