Hepatoprotective effect ofbis(4-methylbenzoyl) diselenide against CCl4-induced oxidative damage in mice

4-Phenylselanyl-7-chloroquinoline attenuates hepatic injury triggered by neonatal exposure to monosodium glutamate in rats

AIMS

Obesity is associated with a spectrum of hepatic abnormalities that can be experimentally induced by injections of monosodium glutamate (MSG) in neonatal rodents. We investigated the protective actions of the repeated therapy with 4-phenylselenyl-7-chloroquinoline (4-PSQ), a quinoline derivative containing selenium, on damage to the liver triggered by early postnatal administration of MSG in male Wistar rats.

MAIN METHODS

Neonatal rats received MSG (4 g/kg, subcutaneous route) or saline (1 ml/kg) from 5 to 14 postnatal day (PND) to induce obesity with consequent damages in the liver. 4-PSQ treatment (5 mg/kg) or canola oil (1 ml/kg) was administered from 60 to 76 PND by the intragastric route. On 76 PND, animals were anesthetized for blood and liver collection. Plasma markers of hepatic function, hepatic lipoperoxidation levels and histology analysis of liver tissue were assessed.

KEY FINDINGS

Our data revealed that treatment with 4-PSQ reverted the increase in plasma transaminases activities observed in MSG rats. Treatment with 4-PSQ reduced plasma lactate levels in obese rats. In the liver, MSG elevated the content of lipoperoxidation which was reverted by 4-PSQ administrations. Lastly, 4-PSQ therapy attenuated the histological alterations induced by MSG.

SIGNIFICANCE

Together, the results indicate a hepatoprotective action of repeated treatment with 4-PSQ in obese 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.

Selenophenes: Introducing a New Element into the Core of Non-Steroidal Estrogen Receptor Ligands

The importance of the heterocyclic core elements with peripheral phenolic and alkyl substituents as a dominant structural motif of ligands for the estrogen receptor (ER) has been well recognized. In this study we expanded the structural diversity of core elements by preparing selenium-containing heterocycles and exploring the activities of these selenophenes on the two ERs, ERα and ERβ. Careful structure-activity relationship (SAR) analysis of their ER binding affinities showed that most selenophenes are ERβ-selective, with the position of the phenol substituents on the selenophene core and the nature of these substituents having a marked effect on their binding affinities. The compound bis(2-fluoro-4-hydroxyphenyl)selenophene (2 f) has the highest relative binding affinity (RBA) of 24.3 for ERβ. In transcription assays, most selenophenes were found to exhibit partial to full agonist activity for both ER subtypes, with compounds bis(2-methyl-4-hydroxyphenyl)selenophene (2 b), bis(4-fluoro-3-hydroxyphenyl)3-bromoselenophene (6 f), and 2,3,5-tris(hydroxyphenyl)thiophenes (8 b and 8 d) profiling as superagonists for ERα; however, several compounds display a range of ERα or ERβ antagonistic activities. A few selenophenes exhibited antiproliferative activity, with compound 8 c showing antiproliferative effects similar to that of 4-hydroxytamoxifen in breast cancer MCF-7 cells while being nontoxic to normal VERO cells. These new ligands could act as models for the development of novel agents leading to improved therapeutics that target the estrogen receptor.

Sonochemistry: An efficient alternative to the synthesis of 3-selanylindoles using CuI as catalyst

Ultrasonic (US) irradiation was successfully used as an alternative energy source to prepare 3-selanylindoles through the direct selanylation of indoles with diorganyl diselenides using CuI (20 mol%) as catalyst and DMSO as the solvent. By using this US-promoted reaction, eleven 3-organylselanylindoles were prepared selectively and in good yields. A comparative study between the reactions under conventional heating, microwave and ultrasound irradiations was performed, and it was observed advantage in using US over the other heating systems.

Organoselenocyanates and symmetrical diselenides redox modulators: Design, synthesis and biological evaluation

Oxidative stress (OS) and disturbed intracellular redox balance have been predominantly observed in different types of cancer, including hepatocellular carcinoma (HCC). Agents which can stop OS multi-stressor events and modulate the intracellular redox state are becoming a major focus in HCC prevention. Among them, compounds with glutathione peroxidase (GPx)-like activity are of particularly concern. We herein report the synthesis of novel series of organoselenocyanates and symmetrical diselenide antioxidants, inspired by the natural redox enzyme, GPx and the synthetic organoselenium ebselen antioxidants. Their cytotoxic activity was evaluated against Hep G2 cells and their antimicrobial activities were evaluated against Candida albicans (C. albicans) fungus as well as against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), gram-negative and gram-positive bacteria, respectively. These compounds were also tested for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), GPx-like activity and bleomycin dependent DNA damage assays and a basic structure-activity relationship was subsequently established. The physicochemical parameters and drug-likeness were computed employing the Molinspiration online property calculation toolkit and MolSoft software. Interestingly, some compounds proved to be more cytotoxic than ebselen and the known anticancer drug 5-Fu and in the same time they showed similar, sometime even more, antifungal activity than the reference antifungal drugs. Among these compounds, compound 16 was considered to be the most interesting with free radical-scavenging activity comparable to ascorbic acid and a GPx-like activity similar to ebselen. As most of these compounds comply with Lipinski's Rule of Five, they promise good bioavailability, which needs to be studied as part of future investigations.

Antinociceptive and anti-hyperalgesic effects of bis(4-methylbenzoyl) diselenide in mice: evidence for the mechanism of action

CONTEXT

The organoselenium compounds have been described to demonstrate several biological activities, including pain management.

OBJECTIVE

This study investigated the antinociceptive, hyperalgesic, and toxic effects of oral administration of bis(4-methylbenzoyl) diselenide (BMD) in mice.

MATERIALS AND METHODS

The antinociceptive and anti-hyperalgesic effects of BMD (1, 5, 10, 25, and 50 mg/kg, p.o.) were evaluated using models of nociception: formalin, capsaicin, bradykinin (BK), cinnamaldehyde, phorbol myristate acetate (PMA), 8-bromo-cAM, and glutamate-induced nociception; and mechanical hyperalgesia induced by carrageenan (Cg) or complete Freund's adjuvant (CFA). The acute toxicity was evaluated by biochemical markers for hepatic and renal damages.

RESULTS

BMD significantly inhibited the licking time of the injected paw in the early and late phases of a formalin test with ED50 values of 14.2 and 10.8 mg/kg, respectively. This compound reduced nociception produced by capsaicin (ED50 of 32.5 mg/kg), BK (ED50 of 24.6 mg/kg), glutamate (ED50 of 28.7 mg/kg), cinnamaldehyde (ED50 of 18.9 mg/kg), PMA (ED50 of 9.6 mg/kg), and 8-bromo-cAMP (ED50 of 24.8 mg/kg). In the glutamate test, the pretreatment with nitric oxide (NO) precursor, L-arginine, reversed antinociception caused by BMD or N(ω)-nitro-L-arginine (L-NOARG), but the effect of BMD was not abolished by naloxone. Mechanical hyperalgesia induced by Cg and CFA was attenuated by BMD, 70 ± 4% and 65 ± 4%, respectively. Furthermore, a single oral dose of BMD did not change plasma aspartate (AST) and alanine aminotransferase (ALT) activities or urea and creatinine levels.

CONCLUSION

BMD demonstrated as a promising compound because of the antinociceptive and anti-hyperalgesic properties in mice.