Homeobox gene-encoded transcription factors in development and mature circadian function of the rodent pineal gland.

Homeobox genes encode transcription factors that are widely known to control developmental processes. This is also the case in the pineal gland, a neuroendocrine brain structure devoted to nighttime synthesis of the hormone melatonin. Thus, in accordance with high prenatal gene expression, knockout studies have identified a specific set of homeobox genes that are essential for development of the pineal gland. However, as a special feature of the pineal gland, homeobox gene expression persists into adulthood, and gene product abundance exhibits 24 h circadian rhythms. Recent lines of evidence show that some homeobox genes even control expression of enzymes catalyzing melatonin synthesis. We here review current knowledge of homeobox genes in the rodent pineal gland and suggest a model for dual functions of homeobox gene-encoded transcription factors in developmental and circadian mature neuroendocrine function.

Synergistic interplay between melatonin and hydrogen sulfide enhances cadmium-induced oxidative stress resistance in stock (Matthiola incana L.).

Ornamental crops particularly cut flowers are considered sensitive to heavy metals (HMs) induced oxidative stress condition. Melatonin (MLT) is a versatile phytohormone with the ability to mitigate abiotic stresses induced oxidative stress in plants. Similarly, signaling molecules such as hydrogen sulfide (H2S) have emerged as potential options for resolving HMs related problems in plants. The mechanisms underlying the combined application of MLT and H2S are not yet explored. Therefore, we evaluated the ability of individual and combined applications of MLT (100 µM) and H2S in the form of sodium hydrosulfide (NaHS), a donor of H2S, (1.5 mM) to alleviate cadmium (Cd) stress (50 mg L-1) in stock (Matthiola incana L.) plants by measuring various morpho-physiological and biochemical characteristics. The results depicted that Cd-stress inhibited growth, photosynthesis and induced Cd-associated oxidative stress as depicted by excessive ROS accumulation. Combined application of MLT and H2S efficiently recovered all these attributes. Furthermore, Cd stress-induced oxidative stress markers including electrolyte leakage, malondialdehyde, and hydrogen peroxide are partially reversed in Cd-stressed plants by MLT and H2S application. This might be attributed to MLT or H2S induced antioxidant plant defense activities, which effectively reduce the severity of oxidative stress indicators. Overall, MLT and H2S supplementation, favorably regulated Cd tolerance in stock; yet, the combined use had a greater effect on Cd tolerance than the independent application.

Melatonin in the mammalian retina: Synthesis, mechanisms of action and neuroprotection.

Melatonin is an important player in the regulation of many physiological functions within the body and in the retina. Melatonin synthesis in the retina primarily occurs during the night and its levels are low during the day. Retinal melatonin is primarily synthesized by the photoreceptors, but whether the synthesis occurs in the rods and/or cones is still unclear. Melatonin exerts its influence by binding to G protein-coupled receptors named melatonin receptor type 1 (MT1) and type 2 (MT2). MT1 and MT2 receptors activate a wide variety of signaling pathways and both receptors are present in the vertebrate photoreceptors where they may form MT1/MT2 heteromers (MT1/2h). Studies in rodents have shown that melatonin signaling plays an important role in the regulation of retinal dopamine levels, rod/cone coupling as well as the photopic and scotopic electroretinogram. In addition, melatonin may play an important role in protecting photoreceptors from oxidative stress and can protect photoreceptors from apoptosis. Critically, melatonin signaling is involved in the modulation of photoreceptor viability during aging and other studies have implicated melatonin in the pathogenesis of age-related macular degeneration. Hence melatonin may represent a useful tool in the fight to protect photoreceptors-and other retinal cells-against degeneration due to aging or diseases.

Effect of exogenous melatonin implant on post-thaw semen quality of buffalo bulls.

Melatonin is an intracellular antioxidant of sperm membrane that protects the cells from lipid peroxidation. Yet, its role as an antioxidant on semen quality of buffalo bulls is still obscure. The present study was undertaken to assess the effect of exogenous melatonin implant (18 mg/50 kg bodyweight) on post-thaw sperm characteristics, oxidative stress, endocrinological profiles and fertility of buffalo bulls. Six apparently healthy breeding Murrah buffalo bulls were randomly selected at bull farm, Guru Angad Dev Veterinary and Animal Sciences University for the present study and divided into two groups viz. control (n = 3) and melatonin implanted group (n = 3). A total of 120 ejaculates were collected from bulls of both groups (n = 60 each) throughout the study period. Most beneficial effects of melatonin implants were observed during post-implantation period. The percentages of post-thaw sperm total and progressive motility, viability and mitochondrial membrane potential were higher (p < .05) in melatonin implanted buffalo bulls compared to controls during post-implantation period. Following melatonin implantation, MDA production in post-thaw semen was lower (p < .05) in melatonin implanted group than in control group. Plasma melatonin and testosterone concentrations were higher (p < .05) in buffalo bulls implanted with melatonin as compared to their control counterparts. No differences (p > .05) in plasma LH concentrations were observed in both groups. First service pregnancy rate was 43.3% using semen of melatonin implanted bulls and 30.0% with semen of controls (p > .05). Thus, melatonin was able to protect sperm membrane against oxidative damage and improve post-thaw semen quality, thereby resulting in higher fertilizing potential of spermatozoa.

Functional characterisation of Dof gene family and expression analysis under abiotic stresses and melatonin-mediated tolerance in pitaya (Selenicereus undatus).

DNA binding proteins with one finger (Dof ) transcription factors are essential for seed development and defence against various biotic and abiotic stresses in plants. Genomic analysis of Dof has not been determined yet in pitaya (Selenicereus undatus ). In this study, we have identified 26 Dof gene family members, renamed as HuDof-1 to HuDof-26 , and clustered them into seven subfamilies based on conserved motifs, domains, and phylogenetic analysis. The gene pairs of Dof family members were duplicated by segmental duplications that faced purifying selection, as indicated by the K a /K s ratio values. Promoter regions of HuDof genes contain many cis -acting elements related to phytohormones including abscisic acid, jasmonic acid, gibberellin, temperature, and light. We exposed pitaya plants to different environmental stresses and examined melatonin's influence on Dof gene expression levels. Signifcant expression of HuDof -2 and HuDof -6 were observed in different developmental stages of flower buds, flowers, pericarp, and pulp. Pitaya plants were subjected to abiotic stresses, and transcriptome analysis was carried out to identify the role of Dof gene family members. RNA-sequencing data and reverse transcription quantitative PCR-based expression analysis revealed three putative candidate genes (HuDof -1, HuDof -2, and HuDof -8), which might have diverse roles against the abiotic stresses. Our study provides a theoretical foundation for functional analysis through traditional and modern biotechnological tools for pitaya trait improvement.

Melatonin: a ferroptosis inhibitor with potential therapeutic efficacy for the post-COVID-19 trajectory of accelerated brain aging and neurodegeneration.

The unprecedented pandemic of COVID-19 swept millions of lives in a short period, yet its menace continues among its survivors in the form of post-COVID syndrome. An exponentially growing number of COVID-19 survivors suffer from cognitive impairment, with compelling evidence of a trajectory of accelerated aging and neurodegeneration. The novel and enigmatic nature of this yet-to-unfold pathology demands extensive research seeking answers for both the molecular underpinnings and potential therapeutic targets. Ferroptosis, an iron-dependent cell death, is a strongly proposed underlying mechanism in post-COVID-19 aging and neurodegeneration discourse. COVID-19 incites neuroinflammation, iron dysregulation, reactive oxygen species (ROS) accumulation, antioxidant system repression, renin-angiotensin system (RAS) disruption, and clock gene alteration. These events pave the way for ferroptosis, which shows its signature in COVID-19, premature aging, and neurodegenerative disorders. In the search for a treatment, melatonin shines as a promising ferroptosis inhibitor with its repeatedly reported safety and tolerability. According to various studies, melatonin has proven efficacy in attenuating the severity of certain COVID-19 manifestations, validating its reputation as an anti-viral compound. Melatonin has well-documented anti-aging properties and combating neurodegenerative-related pathologies. Melatonin can block the leading events of ferroptosis since it is an efficient anti-inflammatory, iron chelator, antioxidant, angiotensin II antagonist, and clock gene regulator. Therefore, we propose ferroptosis as the culprit behind the post-COVID-19 trajectory of aging and neurodegeneration and melatonin, a well-fitting ferroptosis inhibitor, as a potential treatment.

THE EFFECT OF MELATONIN ON THE SERUM LEVEL OF INTERLEUKIN 31 IN HERPESVIRUS SKIN DISEASES ON THE BACKGROUND OF HIV.

The immune system of the skin is the first line of defense against various infections, on the other hand, its strategic location as a key barrier between external and internal environment makes the skin an important tool for maintaining homeostasis, so dermatological lesions are often a manifestation of various pathological conditions. Thus, herpesvirus skin diseases, which are the result of reactivation of a latent infection and occur against the background of human immunodeficiency, may be the first manifestation of HIV. Active study of melatonin in recent years in the dermatological field is associated with interest in its biological action, which extends to the skin due to the melatoninergic system, and promising prospects for the development of new treatments. The aim of this study was to investigate the effect of melatonin on the serum levels of interleukin 31 in herpesvirus skin diseases on the background of HIV. The current study selected 40 HIV patients who had an acute herpesvirus infection caused by HSV-1, HSV-2, VZV, EBV, and HHV-8 were selected. Patients were divided into two groups: group I consisted of patients receiving antiretroviral therapy, valaciclovir in standard therapeutic doses and melatonin as immunomodulatory therapy. Patients in the melatonin group received two melatonin tablet, 3 mg for 14 days, 6 mg daily (two doses of 3 mg). Group II included patients who received antiretroviral therapy in combination with valaciclovir. Serum levels of IL-31 were measured before and after 14 days of therapeutic intervention. The mean serum level of IL-31 was significantly lower in the melatonin group (p˂0.05). Also, in both groups, serum levels of IL-31 showed a significant increase compared to the indicator of the norm. The results of this study showed that melatonin administration could modify inflammatory cytokines secretion such as IL-31. Given the low toxicity of melatonin and its ability to reduce side effects and increase the efficiency of therapeutic agents, its use may be important and significant in combined therapy in combination with highly active antiretroviral therapy.

Efficacy and safety of topical rosuvastatin & melatonin vs. placebo in patients with mild to moderate plaque psoriasis: A preliminary randomized double-blinded clinical trial.

BACKGROUND: Considering the pathogenesis of psoriasis and also the anti-oxidant, immunomodulatory, and anti-inflammatory properties of rosuvastatin and melatonin, the current clinical trial aimed to evaluate the efficacy of topical rosuvastatin and melatonin in patients with mild to moderate psoriasis. METHODS: The current randomized placebo-controlled clinical trial was conducted using a 3-arm parallel group included 77 adult patients (≥18 years old) with mild to moderate plaque psoriasis. Patients were randomized into a 1:1:1 ratio to one of three groups to receive one of the three interventions: melatonin cream, 5.0% (w/w), rosuvastatin cream, 5.0% (w/w), or placebo cream with a similar transparent appearance twice a day for 12 weeks. The primary outcome was severity of the disease using Psoriasis Area Severity Index (PASI). The secondary outcomes included the Dermatological Sum Score (DSS) to assess the erythema, scaling, and plaque elevation and the Dermatology Life Quality Index (DLQI). Photographs of the lesions were also taken at the baseline and at different periodic intervals thereafter. RESULTS: Among 77 randomized patients, 52 (mean (SD) age, 40.67 (10.85) years; 22 (42.30%) men) completed the study. A significant reduction of 45% (mean (SD) of 2.67 (0.98) to 1.74 (1.12)) and 70% (mean (SD) of 2.67 (0.98) to 1.31 (1.13)) in PASI score, and 46% (mean (SD) of 2.91(1.85) to 1.57 (1.11)) and 77% (mean (SD) of 2.91 (1.85) to 0.87 (0.67)) in DSS score on days 30 and 60 with rosuvastatin cream, 5% w/w (P < 0.001) compared with baseline was observed, respectively. Also a significant decrease of 35% (mean (SD) of 2.67 (0.98) to 1.74 (1.12)) and 51% (mean (SD) of 2.67 (0.98) to 1.31 (1.13)) in PASI score, and 40% (mean (SD) of 5.00 (1.58) to 3.00 (1.76))and 61% (mean (SD) of 5.00 (1.58) to 1.92 (1.71)) in DSS score on days 30 and 60 with melatonin cream, 5% w/w (P < 0.001) compared with baseline were observed, respectively. In each of the melatonin or rosuvastatin groups, DLQI improved significantly on days 30 (P < 0.0001) and 60 (P < 0.001) while the changes in the control group were not significant. CONCLUSION: The results of this clinical trial demonstrated that topical melatonin and rosuvastatin diminished the severity of mild to moderate plaque psoriasis with a satisfactory safety profile. Future clinical trials should assess both the long-term efficacy and safety of melatonin and rosuvastatin creams in larger study populations.

Effect of melatonin on developmental competence, mitochondrial distribution, and intensity of fresh and vitrified/thawed in vitro matured buffalo oocytes.

BACKGROUND: In livestock breeding, oocyte cryopreservation is crucial for preserving and transferring superior genetic traits. This study was conducted to examine the additional effect of melatonin to maturation and vitrification media on the in vitro developmental capacity, mitochondrial distribution, and intensity of buffalo oocytes. The study involved obtaining ovaries from a slaughterhouse and conducting two phases. In the first phase, high-quality oocytes were incubated in a maturation medium with or without 10-9M melatonin for 22 h (at 38.5°C in 5% CO2). Matured oocytes were fertilized in vitro and cultured in SOF media for seven days. In the second phase, vitrified in vitro matured oocytes were stored in vitrified media (basic media (BM) containing a combination of cryoprotectants (20% Ethyl Glycol and 20% Dimethyl sulfoxide), with or without melatonin, and then stored in liquid nitrogen. Normal vitrified/thawed oocytes were fertilized in vitro and cultured as described. Finally, the matured oocytes from the fresh and vitrified/thawed groups, both with and without melatonin, were stained using DAPI and Mitotracker red to detect their viability (nuclear maturation), mitochondrial intensity, and distribution using a confocal microscope. The study found that adding 10-9M melatonin to the maturation media significantly increased maturation (85.47%), fertilization rate (84.21%)cleavage (89.58%), and transferable embryo (48.83%) rates compared to the group without melatonin (69.85%,79.88%, 75.55%, and 37.25% respectively). Besides that, the addition of melatonin to the vitrification media improved the recovery rate of normal oocytes (83.75%), as well as the cleavage (61.80%) and transferable embryo (27.00%) rates when compared to the vitrified TCM group (67.46%, 51.40%, and 17.00%, respectively). The diffuse mitochondrial distribution was higher in fresh with melatonin (TCM + Mel) (80%) and vitrified with melatonin (VS2 + Mel groups) (76.70%), Furthermore, within the same group, while the mitochondrial intensity was higher in the TCM + Mel group (1698.60) than other group. In conclusion, Melatonin supplementation improves the developmental competence and mitochondrial distribution in buffalo oocytes in both cases(in vitro maturation and vitrification).

Metabolome and Transcriptome Analysis Revealed the Pivotal Role of Exogenous Melatonin in Enhancing Salt Tolerance in Vitis vinifera L.

Vitis vinifera L. possesses high economic value, but its growth and yield are seriously affected by salt stress. Though melatonin (MT) has been widely reported to enhance tolerance towards abiotic stresses in plants, the regulatory role melatonin plays in resisting salt tolerance in grapevines has scarcely been studied. Here, we observed the phenotypes under the treatment of different melatonin concentrations, and then transcriptome and metabolome analyses were performed. A total of 457 metabolites were detected in CK- and MT-treated cell cultures at 1 WAT (week after treatment) and 4 WATs. Exogenous melatonin treatment significantly increased the endogenous melatonin content while down-regulating the flavonoid content. To be specific, the melatonin content was obviously up-regulated, while the contents of more than a dozen flavonoids were down-regulated. Auxin response genes and melatonin synthesis-related genes were regulated by the exogenous melatonin treatment. WGCNA (weighted gene coexpression network analysis) identified key salt-responsive genes; they were directly or indirectly involved in melatonin synthesis and auxin response. The synergistic effect of salt and melatonin treatment was investigated by transcriptome analysis, providing additional evidence for the stress-alleviating properties of melatonin through auxin-related pathways. The present study explored the impact of exogenous melatonin on grapevines' ability to adapt to salt stress and provided novel insights into enhancing their tolerance to salt stress.

Association between Parkinson's Disease and Cancer: New Findings and Possible Mediators.

Epidemiological evidence points to an inverse association between Parkinson's disease (PD) and almost all cancers except melanoma, for which this association is positive. The results of multiple studies have demonstrated that patients with PD are at reduced risk for the majority of neoplasms. Several potential biological explanations exist for the inverse relationship between cancer and PD. Recent results identified several PD-associated proteins and factors mediating cancer development and cancer-associated factors affecting PD. Accumulating data point to the role of genetic traits, members of the synuclein family, neurotrophic factors, the ubiquitin-proteasome system, circulating melatonin, and transcription factors as mediators. Here, we present recent data about shared pathogenetic factors and mediators that might be involved in the association between these two diseases. We discuss how these factors, individually or in combination, may be involved in pathology, serve as links between PD and cancer, and affect the prevalence of these disorders. Identification of these factors and investigation of their mechanisms of action would lead to the discovery of new targets for the treatment of both diseases.

A Clinical, Pharmacological, and Formulation Evaluation of Melatonin in the Treatment of Ocular Disorders-A Systematic Review.

Melatonin's cytoprotective properties may have therapeutic implications in treating ocular diseases like glaucoma and age-related macular degeneration. Literature data suggest that melatonin could potentially protect ocular tissues by decreasing the production of free radicals and pro-inflammatory mediators. This study aims to summarize the screened articles on melatonin's clinical, pharmacological, and formulation evaluation in treating ocular disorders. The identification of relevant studies on the topic in focus was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines. The studies were searched in the following databases and web search engines: Pubmed, Scopus, Science Direct, Web of Science, Reaxys, Google Scholar, Google Patents, Espacenet, and Patentscope. The search time interval was 2013-2023, with the following keywords: melatonin AND ocular OR ophthalmic AND formulation OR insert AND disease. Our key conclusion was that using melatonin-loaded nano-delivery systems enabled the improved permeation of the molecule into intraocular tissues and assured controlled release profiles. Although preclinical studies have demonstrated the efficacy of developed formulations, a considerable gap has been observed in the clinical translation of the results. To overcome this failure, revising the preclinical experimental phase might be useful by selecting endpoints close to clinical ones.

Impact of Melatonin Supplementation on Sports Performance and Circulating Biomarkers in Highly Trained Athletes: A Systematic Review of Randomized Controlled Trials.

Melatonin (N-acetyl-5 methoxytryptamine) is an indolic neurohormone that modulates a variety of physiological functions due to its antioxidant, anti-inflammatory, and immunoregulatory properties. Therefore, the purpose of this study was to critically review the effects of melatonin supplementation in sports performance and circulating biomarkers related to the health status of highly trained athletes. Data were obtained by performing searches in the following three bibliography databases: Web of Science, PubMed, and Scopus. The terms used were "Highly Trained Athletes", "Melatonin", and "Sports Performance", "Health Biomarkers" using "Humans" as a filter. The search update was carried out in February 2024 from original articles published with a controlled trial design. The PRISMA rules, the modified McMaster critical review form for quantitative studies, the PEDro scale, and the Cochrane risk of bias were applied. According to the inclusion and exclusion criteria, 21 articles were selected out of 294 references. The dose of melatonin supplemented in the trials ranged between 5 mg to 100 mg administered before or after exercise. The outcomes showed improvements in antioxidant status and inflammatory response and reversed liver damage and muscle damage. Moderate effects on modulating glycemia, total cholesterol, triglycerides, and creatinine were reported. Promising data were found regarding the potential benefits of melatonin in hematological biomarkers, hormonal responses, and sports performance. Therefore, the true efficiency of melatonin to directly improve sports performance remains to be assessed. Nevertheless, an indirect effect of melatonin supplementation in sports performance could be evaluated through improvements in health biomarkers.

The Effect of Melatonin on Increasing the Health Related Quality of Life in Non-Metastatic Breast Cancer Patients: Three-Year Follow up a Clinical Trial.

INTRODUCTION: Although breast cancer is common worldwide, if diagnosed early and treated on time, the probability of recovery is high and patients often experience a long life. Reducing the quality of life is a common side effect in patients. Melatonin may have an important role in fatigue, sleep disorders and, as a result, the health-related quality of life (HRQoL) in people. About 184 patients with breast cancer were enrolled in 2 groups: intervention with daily melatonin intake of 18 mg for 3 years (93 patients) and the control group with placebo intake (91 patients). Health-related quality of life and the effect of melatonin on increasing that were evaluated with the EORTC QLQ-C30 questionnaire, third edition at the beginning, 2 months later and 3 years after the beginning of the study. RESULTS: The general score of the HRQoL was significantly different both in the passage of time and in the comparative study of the 2 groups, and it was better in the melatonin group (P < .05). CONCLUSION: Long-term use of 18 mg of melatonin for 3 years in patients with non-metastatic breast cancer can lead to an increase in the patients' quality of life.

Melatonin's effect on hair follicles in a goat (Capra hircus) animal model.

Introduction: Melatonin can treat androgenetic alopecia in males. Goats can be used as animal models to study melatonin treatment for human alopecia. In this study, a meta-analysis of melatonin's effects on goat hair follicles was pursued. Methods: Literature from the last 20 years was searched in Scopus, Science Direct, Web of Science and PubMed. Melatonin's effect on goat hair follicles and litter size were performed through a traditional meta-analysis and trial sequential analysis. A network meta-analysis used data from oocyte development to blastocyst. The hair follicle genes regulated by melatonin performed KEGG and PPI. We hypothesized that there are differences in melatonin receptors between different goats, and therefore completed melatonin receptor 1A homology modelling and molecular docking. Results: The results showed that melatonin did not affect goat primary follicle or litter size. However, there was a positive correlation with secondary follicle growth. The goat melatonin receptor 1A SNPs influence melatonin's functioning. The wild type gene defect MR1 is a very valuable animal model. Discussion: Future studies should focus on the relationship between goat SNPs and the effect of embedded melatonin. This study will provide theoretical guidance for the cashmere industry and will be informative for human alopecia research.

Melatonin-mediated corrective changes in gut microbiota of experimentally chronodisrupted C57BL/6J mice.

Chronic consumption of a high-calorie diet coupled with an altered sleep-wake cycle causes disruption of circadian clock that can impact the gut microbiome leading to metabolic syndrome and associated diseases. Herein, we investigate the effects of a high fat high fructose diet (H) alone or in combination with photoperiodic shifts induced chronodisruption (CD) on gut microbiota of C57BL/6J male mice. Further, the merits of daily evening intraperitoneal administration of melatonin in restoring gut microbiota are studied herein. Experimental groups viz. H, CD and HCD mice recorded higher levels of serum pro-inflammatory cytokines (TNF-α and IL-6) and lower levels of the anti-inflammatory cytokine, IL-10. These findings correlate with a concomitant increase in the transcripts of TLR4, TNF-α, and IL-6 in small intestine of the said groups. A decrement in mRNA levels of Ocln, ZO-1 and Vdr in these groups implied towards an altered gut permeability. These results were in agreement with the observed decrement in percentage abundance of total gut microflora and Firmicutes: Bacteroidetes (F/B) ratio. Melatonin administration accounted for lower-level inflammation (serum and gut) along with an improvement in gut permeability markers. The total abundance of gut microflora and F/B ratio showed an improvement in all the melatonin-treated groups and the same is the highlight of this study. Taken together, our study is the first to report perturbations in gut microbiota resulting due to a combination of photoperiodic shifts induced CD and a high fat high calorie diet-induced lifestyle disorder. Further, melatonin-mediated rejuvenation of gut microbiome provides prima facie evidence of its role in improving gut dysbiosis that needs a detailed scrutiny.

Elucidating the modulatory effect of melatonin on enzyme activity and oxidative stress in wheat: a global meta-analysis.

In our comprehensive meta-analysis, we initially collected 177 publications focusing on the impact of melatonin on wheat. After meticulous screening, 40 published studies were selected, encompassing 558 observations for antioxidant enzymes, 312 for reactive oxygen species (ROS), and 92 for soluble biomolecules (soluble sugar and protein). This analysis revealed significant heterogeneity across studies (I2 > 99% for enzymes, ROS, and soluble biomolecules) and notable publication bias, indicating the complexity and variability in the research field. Melatonin application generally increased antioxidant enzyme activities [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)] in wheat, particularly under stress conditions, such as high temperature and heavy-metal exposure. Compared to control, melatonin application increased SOD, POD, CAT, and APX activities by 29.5, 16.96, 35.98, and 171.64%, respectively. Moreover, oxidative stress markers like hydrogen peroxide (H2O2), superoxide anion (O2), and malondialdehyde (MDA) decreased with melatonin by 23.73, 13.64, and 21.91%, respectively, suggesting a reduction in oxidative stress. The analysis also highlighted melatonin's role in improving carbohydrate metabolism and antioxidant defenses. Melatonin showed an overall increase of 12.77% in soluble sugar content, and 22.76% in glutathione peroxidase (GPX) activity compared to the control. However, the effects varied across different wheat varieties, environmental conditions, and application methods. Our study also uncovered complex relationships between antioxidant enzyme activities and H2O2 levels, indicating a nuanced regulatory role of melatonin in oxidative stress responses. Our meta-analysis demonstrates the significant role of melatonin in increasing wheat resilience to abiotic stressors, potentially through its regulatory impact on antioxidant defense systems and stress response.

Melatonin is a Neuroprotective and Antioxidant Agent against Neurotoxicity Induced by an Intrahippocampal Injection of Nickel in Rats.

The investigation into the hippocampal function and its response to heavy metal exposure is crucial for understanding the mechanisms underlying neurotoxicity, this can potentially inform strategies for mitigating the adverse effects associated with heavy metal exposure. Melatonin is an essential neuromodulator known for its efficacy as an antioxidant. In this study, we aimed to determine whether melatonin could protect against Nickel (Ni) neurotoxicity. To achieve this, we performed an intracerebral injection of Ni (300 µM NiCl2) into the right hippocampus of male Wistar rats, followed by melatonin treatment. Based on neurobehavioral and neurobiochemical assessments, our results demonstrate that melatonin efficiently enhances Ni-induced behavioral dysfunction and cognitive impairment. Specifically, melatonin treatment positively influences anxious behavior, significantly reduces immobility time in the forced swim test (FST), and improves learning and spatial memory abilities. Moreover, neurobiochemical assays revealed that melatonin treatment modulates the Ni-induced alterations in oxidative stress balance by increasing antioxidant enzyme activities, such as superoxide dismutase (SOD) and catalase (CAT). Additionally, we observed that melatonin significantly attenuated the increased levels of lipid peroxidation (LPO) and nitric oxide (NO). In conclusion, the data from this study suggests that melatonin attenuates oxidative stress, which is the primary mechanism responsible for Ni-induced neurotoxicity. Considering that the hippocampus is the main structure involved in the pathology associated with heavy metal intoxication, such as Ni, these findings underscore the potential therapeutic efficacy of melatonin in mitigating heavy metal-induced brain damage.

Exogenous Melatonin Application Accelerated the Healing Process of Oriental Melon Grafted onto Squash by Promoting Lignin Accumulation.

Melatonin (MT) is a vital hormone factor in plant growth and development, yet its potential to influence the graft union healing process has not been reported. In this study, we examined the effects of MT on the healing of oriental melon scion grafted onto squash rootstock. The studies indicate that the exogenous MT treatment promotes the lignin content of oriental melon and squash stems by increasing the enzyme activities of hydroxycinnamoyl CoA ligase (HCT), hydroxy cinnamaldehyde dehydrogenase (HCALDH), caffeic acid/5-hydroxy-conifer aldehyde O-methyltransferase (COMT), caffeoyl-CoA O-methyltransferase (CCoAOMT), phenylalanine ammonia-lyase (PAL), 4-hydroxycinnamate CoA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). Using the oriental melon and squash treated with the exogenous MT to graft, the connection of oriental melon scion and squash rootstock was more efficient and faster due to higher expression of wound-induced dedifferentiation 1 (WIND1), cyclin-dependent kinase (CDKB1;2), target of monopteros 6 (TMO6), and vascular-related NAC-domain 7 (VND7). Further research found that the exogenous MT increased the lignin content of the oriental melon scion stem by regulating CmCAD1 expression, and then accelerated the graft healing process. In addition, the root growth of grafted seedlings treated with the exogenous MT was more vigorous.