Anti-Inflammatory Comparison of Melatonin and Its Bromobenzoylamide Derivatives in Lipopolysaccharide (LPS)-Induced RAW 264.7 Cells and Croton Oil-Induced Mice Ear Edema.

The pineal gland is a neuroendocrine organ that plays an important role in anti-inflammation through the hormone melatonin. The anti-inflammatory effects of melatonin and its derivatives have been reported in both in vitro and in vivo models. Our previous study reported the potent antioxidant and neuroprotective activities of bromobenzoylamide substituted melatonin. In silico analysis successfully predicted that melatonin bromobenzoylamid derivatives were protected from metabolism by CYP2A1, which is a key enzyme of the melatonin metabolism process. Therefore, the anti-inflammatory activities of melatonin and its bromobenzoylamide derivatives BBM and EBM were investigated in LPS-induced RAW 264.7 macrophages and croton oil-induced ear edema in mice. The experiments showed that BBM and EBM significantly reduced production of the inflammatory mediators interleukin-6 (IL-6), prostaglandin E2 (PGE2), and nitric oxide (NO) in a dose-dependent manner, but only slightly affected TNF-α in LPS-induced RAW 264.7 macrophages. This suggests that modifying melatonin at either the N1-position or the N-acetyl side chain affected production of NO, PGE2 and IL-6 in in vitro model. In the croton oil-induced mouse ear edema model, BBM, significantly decreased ear edema thickness at 2-4 h. It leads to conclude that bromobenzoylamide derivatives of melatonin may be one of the potential candidates for a new type of anti-inflammatory agent.

Melatonin- and Ferulic Acid-Based HDAC6 Selective Inhibitors Exhibit Pronounced Immunomodulatory Effects In Vitro and Neuroprotective Effects in a Pharmacological Alzheimer's Disease Mouse Model.

The structures of melatonin and ferulic acid were merged into tertiary amide-based histone deacetylase 6 (HDAC6) inhibitors to develop multi-target-directed inhibitors for neurodegenerative diseases to incorporate antioxidant effects without losing affinity and selectivity at HDAC6. Structure-activity relationships led to compound 10b as a hybrid molecule showing pronounced and selective inhibition of HDAC6 (IC50 = 30.7 nM, > 25-fold selectivity over other subtypes). This compound shows comparable DPPH radical scavenging ability to ferulic acid, comparable ORAC value to melatonin and comparable Cu2+ chelating ability to EDTA. It also lacks neurotoxicity on HT-22 cells, exhibits a pronounced immunomodulatory effect, and is active in vivo showing significantly higher efficacy in an AD mouse model to prevent both Aß25-35-induced spatial working and long-term memory dysfunction at lower dose (0.3 mg/kg) compared to positive control HDAC6 inhibitor ACY1215 and an equimolar mixture of the three entities ACY1215, melatonin and ferulic acid, suggesting potentially disease-modifying properties.

Melatonin: From Pharmacokinetics to Clinical Use in Autism Spectrum Disorder.

The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin's effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.

Sleep variability, 6-sulfatoxymelatonin, and diabetic retinopathy.

PURPOSE: Recent evidence suggests that diabetic retinopathy (DR) is associated with abnormal melatonin regulation, possibly related to dysfunction of the melanopsin-expressing intrinsically photosensitive retinal ganglion cells. This study explored melatonin regulation in type 2 diabetes (T2D) patients with DR and its relation to sleep and circadian functioning. METHODS: Thirty-five participants (10 non-diabetic controls, 10 T2D without DR, and 15 T2D with DR) were recruited. Overnight urine 6-sulfatoxymelatonin (aMT6s) and objective sleep and wrist activity (7-day actigraphy) were obtained. RESULTS: After adjusting for covariates, having T2D with DR was significantly associated with lower urinary aMT6s (ß = - 1.369, p = 0.004) compared with controls, while having T2D without DR was not (p = 0.418). T2D patients with DR reported poorer sleep quality (p = 0.014) and had greater variability of sleep duration (p = 0.017) than others, while no differences were found in sleep duration, efficiency, and rest-activity rhythm. After adjusting for covariates, lower nocturnal aMT6s was significantly associated with greater sleep variability. CONCLUSION: T2D patients with DR exhibited low overnight production of aMT6s which likely contributed to sleep irregularities possibly due to weak circadian signaling. Whether or not melatonin supplementation could improve health in T2D patients with DR remains to be explored.

Meta-analysis of melatonin levels in cluster headache-Review of clinical implications.

Cluster headache (CH) has been associated with circadian disturbances. The present systematic review examined available evidence for the utilization of melatonin (MT) in CH prophylaxis. First, case-control studies assessing nocturnal MT or its urine-expelled metabolite 6-sulfatoxymelatonin (aMT6s) in CH individuals and healthy controls (HC) were reviewed and meta-analyzed. Secondly, the results from randomized controlled trials (RCTs) and non-randomized studies evaluating MT's use in the prevention of CH were discussed. Literature search included MEDLINE, EMBASE, CENTRAL, PsycINFO, trial registries, Google Scholar, and OpenGrey. Bouts and remissions were assessed separately. Ten case-control studies (adult participants) were retrieved. Seven evaluated serum MT; meta-analysis involved only three of them (due to deficient reporting, n: bout = 31, remission = 38, HC = 31). Results were compatible with lower nocturnal serum MT levels during bouts [bout-HC; FE-MD = -29.89 pg/mL, 95% CI = (-46.00, -13.78), remission-HC; FE-MD = -2.40 pg/mL, 95% CI = (-16.57, 21.38), bout-remission; RE-MD = -32.10 pg/mL, 95% CI = (-56.78, -7.42)]. Nocturnal urinary melatonin was appraised in two studies, but reporting issues impeded the capitalization of the results. Nocturnal urine aMT6s was evaluated by two studies (n: bout = 29, remission = 22, HC = 20), and pooled results were indicative of lower aMT6s concentration in CH individuals during both active and inactive periods [bout-HC; FE-MD = -9.63 µg/nocturnal urine collection, 95% CI = (-14.40, -4.85), remission-HC; FE-MD = -9.12 µg/nocturnal urine collection, 95% CI = (-14.63,-3.62), bout-remission; FE-MD = -0.58 µg/nocturnal urine collection, 95% CI = (-4.58, 3.42)]. Regarding CH prophylaxis, one RCT and two non-randomized trials were retrieved, involving a total of 41 adult CH individuals (11-episodic, 31-chronic) and rendering the deduction of any conclusions precarious. Overall, available data for the role use of MT in CH are insufficient and inconclusive. Complementary studies evaluating endogenous MT concentrations and MT administration to patients with CH are warranted.

Endogenous Melatonin Levels and Therapeutic Use of Exogenous Melatonin in Migraine: Systematic Review and Meta-Analysis.

BACKGROUND: Sleep disorders and circadian dysregulation appear to be associated with primary headache disorders. OBJECTIVE: The aim of this study was to review the existing evidence for the deployment of melatonin in migraine prophylaxis. Initially, case-control studies investigating nocturnal melatonin and 6-sulphatoxymelatonin (aMT6s, melatonin metabolite discarded by the urine) levels in patients with migraine and healthy controls (HC) would be reviewed and meta-analyzed. Second, results from randomized controlled trials (RCTs) and non-randomized studies evaluating the use of melatonin in migraine would be synthesized. METHODS: MEDLINE EMBASE, CENTRAL, PsycINFO, trial registries, Google Scholar, and OpenGrey were comprehensively searched. The quality of studies was assessed according to the Newcastle-Ottawa Scale (case-control studies) and the Risk-of-Bias Cochrane tool (RCTs). Random-effects (RE) or fixed-effects (FE) model was used based on heterogeneity among studies (homogeneity assumed when PQ > 0.1 and I2  < 30%). Publication bias was assessed by funnel plots. RESULTS: Literature search provided 11 case-control studies. Evidence was compatible with lower nocturnal serum [5 of 6 studies were synthesized due to deficient reporting of 1 abstract, migraine n = 197, HC n = 132, RE MD = -12.29 pg/ml, 95%CI = (-21.10, -3.49)] and urinary melatonin [3 studies, migraine n = 30, HC n = 29, RE MD = -0.12 nmol/nocturnal (12 hours) urinary collection, 95%CI = (-0.22, -0.03)], as well as urine aMT6s levels [1 study, migraine n = 146, HC n = 74, MD = -11.90 µg/nocturnal (12 hours) urine collection, 95%CI = (-19.23, -4.57)] in adult migraine patients compared to HC [1 study involving children did not reveal any difference regarding nocturnal urine aMT6s, n = 18 per group, MD = -6.00 µg/nocturnal (12 hours) urine collection, 95%CI = (-21.19, 9.19)]. Regarding the treatment-prevention of migraine, 7 RCTs and 9 non-randomized studies were retrieved. Data synthesis was not feasible for the comparison of melatonin and placebo due to the existing clinical and methodological heterogeneity of the 5 relevant RCTs. Overall, melatonin was more efficacious and equally safe with placebo in the prevention of migraine in adults (3 of 4 RCTs provided superior efficacy results for melatonin, 1 RCT revealed no difference regarding Headache Frequency -HF-), while there are limited data for children (1 RCT revealed no difference against placebo regarding HF). Additionally, no difference was revealed between melatonin and amitriptyline (1 RCT), sodium valproate (1 RCT) or propranolol (1 non-randomized study) with respect to their efficacy in adults with migraine, while melatonin was more effective than pizotifen (1 RCT). In children with migraine, amitriptyline is more efficacious regarding most assessed parameters (2 studies, n = 85 per group, HF: RE MD = 4.03, 95%CI = (2.64, 5.42), Headache Duration: RE MD = 0.72, 95%CI = (0.41, 1.03), Headache Severity: FE MD = 1.57, 95%CI = (1.13, 2.00), Response to Treatment: FE MD = 0.33, 95%CI = (0.16, 0.69), Headache Induced Disability Severity: RE MD = 6.07, 95%CI = (-11.87, 24.01 ), Analgesic Consumption - assessed in 1 study, n = 40 per group - MD = 1.11, 95%CI = (-0.10, 2.32)), although melatonin presents a superior safety profile than amitriptyline both in adults and in children. CONCLUSIONS: Melatonin may be of potential benefit in the treatment-prevention of migraine in adults, but complementary evidence from high-quality RCTs is required.

Melatonin-sulforaphane hybrid ITH12674 attenuates glial response in vivo by blocking LPS binding to MD2 and receptor oligomerization.

Neuroinflammation is increasingly associated to the onset and progression of neurodegenerative diseases. Furthermore, several lines of evidence have demonstrated the capacity of aberrant protein aggregates to activate the immune response, accelerating the advance of the disease. Compound ITH12674 is a melatonin-sulforaphane hybrid designed to exert a dual drug-prodrug mechanism of action that combines potent NRF2 induction and free radical scavenger activity. ITH12674 also showed neuroprotective properties in oxidative stress related models, that were dependant on its NRF2 inducing properties. Given the high impact of neuroinflammation in the pathogenesis of neurodegeneration, we foresaw to study the anti-inflammatory properties of ITH12674. ITH12674 reduced inflammatory markers in glial cell cultures and hippocampal tissue after LPS administration. The anti-inflammatory effect was related to inhibition of TLR4 receptors due to a direct interaction with the TLR4/MD2 complex at the hydrophobic cavity of MD2. ITH12674 is endowed with anti-inflammatory properties, that are complementary to the NRF2 inducing activity and neuroprotective properties. Thus, ITH12674 could be of potential interest for the treatment of diseases with chronic neuroinflammation.

Dietary supplement of tomato can accelerate urinary aMT6s level and improve sleep quality in obese postmenopausal women.

The aim of this study was to investigate the effect of the ingestion of tomato before bed on obese postmenopausal women's urinary 6-sulphatoxymelatonin (aMT6s) level and sleep quality. We quantified melatonin concentrations in beefsteak tomato, black tomato, and two commercial tomato juices and found that beefsteak tomato contained the highest level of melatonin. In this 8-week open-label, randomized controlled dietary intervention trial, 36 subjects completed the entire trial. The tomato group ate 250 g of beefsteak tomatoes 2 h before sleep for 8 weeks. Blood and urine samples were collected at the baseline and in the 8th week and were analyzed. The Pittsburgh Sleep Quality Index (PSQI) in the tomato group significantly decreased with time (p for trend = 0.0297). After 8 weeks of the beefsteak intervention, all components of the PSQI in tomato group had significantly improved, and their aMT6s level was 10-fold significantly higher than that of the control group. Therefore, supplementation with beefsteak tomato before sleep can increase circulating melatonin and improve sleep quality in obese postmenopausal women.

Bright Light Therapy Increases Blood Pressure and Changes the Structure of Circadian Rhythm of Melatonin Secretion in Spontaneously Hypertensive Rats.

Phototherapy (therapy with bright light) is widely used to treat seasonal affective disorders, different types of depression, sleep disorders, and other diseases; it has no significant contraindications, but its effects on functional state and biological rhythms of the cardiovascular system in hypertension are poorly studied. In experiments on Wistar-Kyoto and SHR (spontaneously hypertensive rats) rats, the effect of bright light therapy on the daily profile of BP, HR, and production of epiphyseal melatonin was investigated. Phototherapy was simulated by exposure to 9000-lux cold light at the level animal eyes over 1 h (from 10.00 to 11.00 h) with LED lamps. In freely moving rats (free access to food), daily profiles of BP and HR were studied by 24-h continuous telemetry monitoring. The production of epiphyseal melatonin was assessed by measuring urinary concentration of its stable metabolite 6-sulfatoxymelatonin (aMT6s) during the day and night. During phototherapy, systolic BP significantly increased in in animals of both lines and diastolic BP increased in SHR rats. This effect persisted after the end of phototherapy session. Bright light had no effect on HR. In Wistar-Kyoto rats, phototherapy induced a significant decrease in daily concentration of aMT6s, but its nocturnal level did not change. In SHR rats, bright light therapy significantly decreased nighttime concentration of aMT6s in the urine and had no effect on daytime concentration of this metabolite. As a result, the difference between the night and day levels of aMT6s in the urine was leveled. Phototherapy produced more pronounced and less favorable effect on animals with primary arterial hypertension.

The effects of a sleep/recovery supplement: 'Night Time Recharge' on sleep parameters in young adults.

BACKGROUND: Concentrated cherry juice reportedly contains melatonin which, in turn, has been highlighted as an important regulator in initiating sleep. AIM: The present investigation aims to clarify whether Night Time Recharge (NTR), a marketed sleep aid containing cherry extract, improves key sleep parameters in young, active adults with mildly poor sleep. METHODS: A double-blind, randomized, placebo-controlled, cross-over study design was employed. Twenty participants (nine female) consumed either NTR or a placebo for seven days. Accelerometers were used to assess sleep quality and physical activity levels. Urinary levels of 6-sulphatoxymelatonin (6-SMT), a marker of melatonin synthesis, was assessed via enzyme-linked immunosorbent assay. RESULTS: 6-SMT levels increased following NTR treatment (28.95 ng/ml) compared with placebo (4.0 ng/ml) (p < 0.001). There was also a significant difference (p = 0.047) in dietary tryptophan consumption during the NTR treatment (1236 mg) versus placebo (1149 mg). No trace of melatonin was detected from our analysis of the supplement. NTR had no significant effect on any sleep parameters with the exception of sleep latency (p = 0.001). CONCLUSIONS: As chemical analysis of NTR by liquid-chromatography mass-spectrometry identified no detectable melatonin, the tryptophan content of the supplement is a likely reason for improvement in sleep latency. These results are in contrast to previous studies which have found a positive effect on sleep following cherry supplementation. Future work should focus on sleep latency and investigating whether cherry juice is effective in participants with problems in initiating sleep.