Exploring the antioxidant potential of chalcogen-indolizines throughout in vitro assays

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are highly reactive molecules produced naturally by the body and by external factors. When these species are generated in excessive amounts, they can lead to oxidative stress, which in turn can cause cellular and tissue damage. This damage is known to contribute to the aging process and is associated with age-related conditions, including cardiovascular and neurodegenerative diseases. In recent years, there has been an increased interest in the development of compounds with antioxidant potential to assist in the treatment of disorders related to oxidative stress. In this way, compounds containing sulfur (S) and/or selenium (Se) have been considered promising due to the relevant role of these elements in the biosynthesis of antioxidant enzymes and essential proteins with physiological functions. In this context, studies involving heterocyclic nuclei have significantly increased, notably highlighting the indolizine nucleus, given that compounds containing this nucleus have been demonstrating considerable pharmacological properties. Thus, the objective of this research was to evaluate the in vitro antioxidant activity of eight S- and Se-derivatives containing indolizine nucleus and different substituents. The in vitro assays 1,1-diphenyl-2-picryl-hydrazil (DPPH) scavenger activity, ferric ion (Fe3+) reducing antioxidant power (FRAP), thiobarbituric acid reactive species (TBARS), and protein carbonylation (PC) were used to access the antioxidant profile of the compounds. Our findings demonstrated that all the compounds showed FRAP activity and reduced the levels of TBARS and PC in mouse brains homogenates. Some compounds were also capable of acting as DPPH scavengers. In conclusion, the present study demonstrated that eight novel organochalcogen compounds exhibit antioxidant activity.

Antidepressant-Like Effect of a Selenoindolizine in Mice: In Vivo and In Silico Evidence for the Involvement of the Serotonergic 5-HT2A/C Receptors

The monoaminergic dysfunction plays a central role in major depressive disorder (MDD), a mental disturbance associated with constant feeling of sadness and lack of interest. The available treatments do not present a desirable efficacy and some of them provoke several adverse effects. In this context, organoselenium compounds and molecules containing the indolizine nucleus have demonstrated interesting pharmacological properties, including antidepressant-like effects. In this study, the antidepressant-like effect of 2-phenyl-1-(phenylselanyl)indolizine (SeI), a selenium-containing indolizine derivative, was investigated on the forced swimming test (FST) and on the tail suspension test (TST) in male Swiss mice. The involvement of the serotonergic system in this effect was also accessed. The selenium compound SeI (10-100 mg/kg, intragastrical (i.g.)) was administered 0.5 h before the behavioral tests, and it diminished the immobility on both FST and TST experiments, which is an indication of antidepressant-like effect. No changing in the locomotor motion was observed in the open-field test (OFT). The anti-immobility effect of SeI was not altered by the preadministration of the selective serotonergic receptor antagonists ondansetron (1 mg/kg, intraperitoneally (i.p.), antagonist of 5-HT₃ receptor) and WAY100635 (0.1 mg/kg, subcutaneous route (s.c.), antagonist of 5-HT_1A receptor). In contrast, the preadministration of ketanserin (1 mg/kg, i.p., antagonist of 5-HT_2A/C receptor) blocked this effect, demonstrating that the antidepressant-like effect of SeI involves 5-HT_2A/C. In addition, molecular docking studies showed a strong interaction between SeI and the receptors of 5-HT_2A and 5-HT_2C. The toxicological results demonstrated that SeI has low potential to cause adverse effects in mice. It was found that the antidepressant-like effect of SeI is related to modulation of the serotonergic system, and this selenium compound could be included in new treatment approaches for MDD.

Effect of m-Trifluoromethyl-diphenyl diselenide on the Pain-Depression Dyad Induced by Reserpine: Insights on Oxidative Stress, Apoptotic, and Glucocorticoid Receptor Modulation

Chronic pain and depression often coexist sharing common pathological mechanisms, and available analgesics and antidepressants have demonstrated limited clinical efficacy. Evidence has demonstrated that neuronal oxidative stress, apoptosis, and also glucocorticoid receptor dysregulation facilitate the occurrence and development of both chronic pain and depression. This study evaluated the effect of the organoselenium compound m-trifluoromethyl-diphenyl diselenide [(m-CF₃-PhSe)₂] in the pain-depression comorbidity induced by reserpine. Mice were treated with reserpine 0.5 mg/kg for 3 days (intraperitoneal, once a day), and in the next 2 days, they were treated with (m-CF₃-PhSe)₂ 10 mg/kg (intragastric, once a day). Thirty minutes after the last administration of (m-CF₃-PhSe)₂, mice were subjected to the behavioral testing. (m-CF₃-PhSe)₂ treatment reverted the reserpine-increased thermal hyperalgesia and depressive-like behavior observed in the hot-plate test and forced swimming test, respectively. Reserpine provoked a decrease of crossings and rearings in the open-field test, while (m-CF₃-PhSe)₂ presented a tendency to normalize these parameters. Reserpine and/or (m-CF₃-PhSe)₂ treatments did not alter the locomotor activity of mice observed in the rota-rod test. These effects could be related to modulation of oxidative stress, apoptotic pathway, and glucocorticoid receptors, once (m-CF₃-PhSe)₂ normalized thiobarbituric acid reactive substances and 4-hydroxynonenal modified protein levels, markers of lipoperoxidation, poly(ADP-ribose) polymerase cleaved/total ratio, and glucocorticoid receptor levels increased by reserpine in the hippocampus. Considering that pain-depression dyad is a complex state of difficult treatment, this organoselenium compound could raise as an interesting alternative to treat pain-depression condition.

Antidepressant-like effect of a selenopropargylic benzamide in mice: involvement of the serotonergic system

RATIONALE

Major depressive disorder is a psychiatric disorder that requires considerable attention, since it dramatically impairs the quality of life of the sufferers. The available treatments do not have the efficacy needed, often presenting several side effects. Organoselenium compounds and benzamides have presented some pharmacological properties, among them an antidepressant-like effect.

OBJECTIVES AND METHODS

This study evaluated the antidepressant-like effect of N-(3-(phenylselanyl)prop-2-yn-1-yl)benzamide (SePB), an organoselenium compound containing a benzamide moiety, on the forced swimming test (FST) and the tail suspension test (TST) in mice, as well as the involvement of the serotonergic system in its effect.

RESULTS

SePB, tested after different times (15-120 min) and doses (1-50 mg/kg, intragastrically (i.g.)), reduced immobility of male mice during FST and TST, without changing locomotor activity in the open-field test (OFT), demonstrating its antidepressant-like effect. SePB (10 mg/kg) also produced an antidepressant-like effect in female mice in the TST. The preadministration of the serotonin (5-HT) depletor p-chlorophenylalanine (pCPA; 100 mg/kg, intraperitoneal route (i.p.) once daily for 4 days) prevented the anti-immobility effect of SePB, indicating that the serotonergic system is involved in the SePB antidepressant-like effect. The preadministration of the selective serotonergic receptor antagonists WAY100635 (0.1 mg/kg, subcutaneous route (s.c.), a selective 5-HT_1A receptor antagonist), ketanserin (1 mg/kg, i.p., a 5-HT_2A/2C receptor antagonist), and ondansetron (1 mg/kg, i.p., a selective 5-HT₃ receptor antagonist) also prevented the anti-immobility effect of SePB, demonstrating that these receptors are involved in the antidepressant-like effect of SePB.

CONCLUSION

The search for new antidepressants drugs is a noteworthy goal. This study has described a new compound with an antidepressant-like effect, whose mechanism of action is related to modulation of the serotonergic system.

Generalised urticaria in a young woman treated with clomipramine and after ingestion of codfish

We report a case of generalized dermatitis and itch induced by a possible drug-food interaction in a young woman who was consuming clomipramine for Obsessive Compulsive Disorder (OCD). A 33-year-old woman affected by anxiety symptoms presented to our observation for a clinical evaluation. After psychiatric evaluation, the diagnosis of OCD was performed according to DSM-IV-TR and a pharmacological treatment with clomipramine (75-100 mg/day) plus alprazolam (0.5 mg/day) was started. About one month later, the patient developed a severe generalized urticaria with intense itch. A new anamnesis revealed that on the day before the development of the skin rash, no other drug was consumed and the patient had eaten codfish; clomipramine was then gradually discontinued and changed into paroxetine (30 mg/day). At the moment the patient does not show any OCD related symptom and any adverse event to paroxetine treatment has been recorded. We postulate a possible interaction between clomipramine and codfish ingestion. Allergic potential of clomipramine was investigated, while clomipramine de-challenge induced a decrease of the skin rash, the drug re-challenge performed one month later did not induce any adverse event. In contrast, when the combined re-challenge of codfish and clomipramine was performed urticaria was newly observed. The Naranjo Probability Scale Score suggested a probable causal relationship between drug-food interaction and the skin rash. In conclusion, we suggest evaluating also the complete risk of drug-food interaction occurring on clomipramine treatment.

Bryostatin-1 and IL-2 synergize to induce IFN-gamma expression in human peripheral blood T cells: implications for cancer immunotherapy

Bryostatin-1 (Bryo-1), a protein kinase C modulator with antineoplastic activity, may exert some of its antitumor activity through activation of the immune response. Studies in tumor-bearing hosts have indicated that the T cell response, particularly IFN-gamma production, is impaired. To evaluate whether Bryo-1 plus IL-2 may affect the activation pattern of T cells, we investigated the expression of IFN-gamma mRNA and protein in human primary T cells. Northern blot analysis and ELISAs demonstrated that Bryo-1 and IL-2 synergized to induce both IFN-gamma mRNA and protein expression. This synergistic induction was seen within 3 h of treatment and with as little as 10 U/ml IL-2 and 1.0 ng/ml Bryo-1. In vitro transcription assays revealed that Bryo-1 plus IL-2 induced transcriptional activation of the IFN-gamma gene. Furthermore, mRNA stability studies indicated that this treatment also enhanced the IFN-gamma mRNA half-life. Both CD4(+) and CD8(+) T cells responded to the treatment with IFN-gamma expression. The induction of the IFN-gamma expression was decreased by a specific p38 mitogen-activated protein kinase inhibitor, but not by a protein kinase C inhibitor. Our results demonstrate for the first time that Bryo-1 in combination with IL-2 control IFN-gamma gene expression at both the transcriptional and post-transcriptional levels through a p38 mitogen-activated protein kinase-dependent process. Given the pivotal role that IFN-gamma plays in the orchestration of an effective Th1 type of response, our results suggest that Bryo-1 plus IL-2 may be a valuable combined therapy for cancer treatment.

Enhanced B7-2 gene expression by interferon-gamma in human monocytic cells is controlled through transcriptional and posttranscriptional mechanisms

B7-2 is a costimulatory molecule expressed on professional antigen-presenting cells that provides T cells with a critical signal resulting in T-cell activation. Interferon-gamma (IFN-gamma) enhances B7-2 protein expression in monocytic cells. However, the molecular mechanisms controlling the enhanced expression of B7-2 are poorly understood. Northern blot and flow cytometry analysis revealed that human monocytes and the human monocytic cell line MonoMac6 (MM6) constitutively expressed B7-2 mRNA and protein and IFN-gamma treatment further enhanced the expression of both molecules. The ability of IFN-gamma to enhance B7-2 mRNA was evident at the dose of 31 U/mL and reached plateau levels at 500 U/mL. The effects of IFN-gamma on B7-2 mRNA expression were time dependent and occurred within 3 hours of treatment and increased through 24 hours. In vitro transcription assays and mRNA stability experiments showed that IFN-gamma increases both transcriptional activity and the stability of B7-2 mRNA. Treatment of MM6 cells with cycloheximide showed that de novo protein synthesis was not required for the IFN-gamma-enhanced expression of B7-2 mRNA. Overall, these studies show for the first time that IFN-gamma-enhanced expression of B7-2 protein in human monocytic cells is controlled at the gene level through a dual mechanism involving transcriptional and posttranscriptional mechanisms.