Melatonin inhibits 6-hydroxydopamine production in the brain to protect against experimental parkinsonism in rodents

Protective Effect of Resveratrol Combined with Levodopa Against Oxidative Damage in Dopaminergic Neurons

Levodopa (L-3,4-dihydroxyphenylalanine, L-Dopa) alleviates the symptoms of Parkinson's disease (PD), yet prolonged usage may give rise to severe adverse effects. Resveratrol (RSV) is a potent antioxidant, anticancer and anti-inflammatory agent. And a variety of polyphenol antioxidant compounds derived from RSV combined with levodopa have demonstrated neuroprotective activity against neuronal cell death. The purpose of this study was to examine the impact of this combination of RSV and L-Dopa on the survival rate, growth status, and reactive oxygen species (ROS) of MES23.5 dopamine (DA) neuron cells. In this study, we induced MPP+ in MES23.5 dopamine neuron cells and observed their survival rate, growth status, ROS content, as well as the effect of RSV combined with L-Dopa on cell survival. We also measured malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity levels as indicators of mitochondrial function, oxidative stress, and oxidative damage in the cells. Our results indicated that the MES23.5 dopamine neurons had decreased survival, poor growth status, and increased ROS content after MPP+ induction. Moreover, we found that MDA levels were elevated, and SOD activity levels were decreased, suggesting that the cells experienced abnormal mitochondrial function. However, when RSV was combined with L-Dopa, the cells showed a reduced level of MPP + -induced oxidative damage, with a more significant inhibitory effect observed in the RSV group at a concentration of 50 μmol/L. In conclusion, we found that the effects of co-administration of RSV with L-Dopa (100 μmol/L) was more effective than L-Dopa administered at the high dose. Thus, we found that RSV has the potential to reduce the dose of L-Dopa required to improve PD symptoms.

A neoteric annotation on the advances in combination therapy for Parkinson's disease: nanocarrier-based combination approach and future anticipation. Part I: exploring theoretical insights and pharmacological advances

INTRODUCTION

Parkinson's disease (PD) is a neurological condition defined by a substantial reduction in dopamine-containing cells in the substantia nigra. Levodopa (L-Dopa) is considered the gold standard in treatment. Recent research has clearly shown that resistance to existing therapies can develop. Moreover, the involvement of multiple pathways in the nigrostriatal dopaminergic neuronal loss suggests that modifying the treatment strategy could effectively reduce this degeneration.

AREAS COVERED

This review summarizes the key concerns with treating PD patients and the combinations, aimed at effectively managing PD. Part I focuses on the clinical diagnosis at every stage of the disease as well as the pharmacological treatment strategies that are applied throughout its course. It methodically elucidates the potency of multifactorial interventions in attenuating the disease trajectory, substantiating the rationale for co-administration of dual or multiple therapeutic agents. Significant emphasis is laid on evidence-based pharmacological combinations for PD management.

EXPERT OPINION

By utilizing multiple drugs in a combination fashion, this approach can leverage the additive or synergistic effects of these agents, amplify the spectrum of treatment, and curtail the risk of side effects by reducing the dose of each drug, demonstrating significantly greater efficacy.

The neuroprotective effect of traditional Chinese medicinal plants-A critical review

Neurodegenerative and neuropsychiatric diseases are increasingly affecting individuals' quality of life, thus increasing their cost to social and health systems. These diseases have overlapping mechanisms, such as oxidative stress, protein aggregation, neuroinflammation, neurotransmission impairment, mitochondrial dysfunction, and excitotoxicity. Currently, there is no cure for neurodegenerative diseases, and the available therapies have adverse effects and low efficacy. For neuropsychiatric disorders, such as depression, the current therapies are not adequate to one-third of the patients, the so-called treatment-resistant patients. So, searching for new treatments is fundamental. Medicinal plants appear as a strong alternative and complement towards new treatment protocols, as they have been used for health purposes for thousands of years. Thus, the main goal of this review is to revisit the neuroprotective potential of some of the most predominant medicinal plants (and one fungus) used in traditional Chinese medicine (TCM), focusing on their proven mechanisms of action and their chemical compositions, to give clues on how they can be useful against neurodegeneration progression.

Beneficial Effect of Melatonin on Motor and Memory Disturbances in 6-OHDA-Lesioned Rats

Previous evidence has shown a link between neurodegenerative diseases, including Parkinson's disease (PD), and melatonin. The data in the literature about the impact of the hormone under different experimental PD conditions are quite controversial, and its effect on memory impairment in the disease is very poorly explored. The current research was aimed at investigating the role of melatonin pretreatment on memory and motor behavior in healthy rats and those with the partial 6-hydroxydopamine (6-OHDA) model of PD. All rodents were pretreated with melatonin (20 mg/kg, intraperitoneally) for 5 days. At 24 h and 7 days after the first treatment for healthy rats, and at the second and third week post-lesion for those with PD, the animals were tested behaviorally (apomorphine-induced rotations, rotarod, and passive avoidance tests). The neurochemical levels of dopamine (DA), acetylcholine (ACh), noradrenaline (NA), and serotonin (Sero) in the brain were also determined. The results showed that in healthy animals, melatonin pretreatment had amnestic and motor-suppressive effects and did not change the levels of measured brain neurotransmitters. In animals with PD, melatonin pretreatment exerted a neuroprotective effect, manifested as a significantly decreased number of apomorphine-induced rotations, reduced number of falls in the rotarod test, and improved memory performance. The brain DA and ACh concentrations in the same animals were restored to the control levels, and those of NA and Sero did not change. Our results demonstrate a beneficial effect of melatonin on memory and motor disturbance in 6-OHDA-lesioned rats.

Mitophagy could fight Parkinson's disease through antioxidant action

During aging, the process of mitophagy, a system that allows the removal of dysfunctional mitochondria through lysosomal degradation, starts to malfunction. Because of this defect, damaged mitochondria are not removed correctly, and their decomposing components accumulate inside the cells. Dysfunctional mitochondria that are not removed by mitophagy produce high amounts of reactive oxygen species (ROS) and, thus, cause oxidative stress. Oxidative stress, in turn, is very harmful for the cells, neuronal cells, in particular. Consequently, the process of mitophagy plays a crucial role in mitochondria-related disease. Mitochondrial dysfunctions and oxidative stress are well-established factors contributing to Parkinson's disease (PD), one of the most common neurodegenerative disorders. In this review, we report various known antioxidants for PD treatments and describe the stimulation of mitophagy process as a novel and exciting method for reducing oxidative stress in PD patients. We describe the different mechanisms responsible for mitochondria removal through the mitophagy process. In addition, we review the functional connection between mitophagy induction and reduction of oxidative stress in several in vitro models of PD and also agents (drugs and natural compounds) already known to be antioxidants and to be able to activate mitophagy. Finally, we propose that there is an urgent need to test the use of mitophagy-inducing antioxidants in order to fight PD.

Garcinol, a multifaceted sword for the treatment of Parkinson's disease

Garcinol, the principal phytoconstituent of plants belonging to the genus Garcinia, is known for its anti-oxidant as well as anti-inflammatory properties, which can be extended to its possible neuroprotective role. Recent reports disseminate the capacity of garcinol to influence neuronal growth and survival, alter the neurochemical status in brain, as well as regulate memory and cognition. The concomitant neuro-rescue property of garcinol may render it as an effective compound in Parkinson's disease (PD) therapeutics since it is capable of ameliorating the related pathophysiological changes. Emerging pieces of evidence linking histone acetylation defects to the progression of neurodegenerative diseases provide an effective basis for targeting PD. Hyperacetylation of histones has been reported in Parkinsonian brain, which demands the use of pharmacological inhibitors of histone acetyltransferases (HAT). Garcinol serves as a potent natural HAT inhibitor and has unveiled promising results in molecular interaction studies against Monoamine oxidase B (MAO-B) and Catechol-O-Methyltransferase (COMT), as well as in L-DOPA induced dyskinesia. This review highlights the prospective implications of garcinol as a novel anti-Parkinsonian agent, and establishes a bridge between histone acetylation defects and the pathological aspects of PD.

Melatonin protects against behavioral deficits, dopamine loss and oxidative stress in homocysteine model of Parkinson's disease

AIM

Hyperhomocysteinemia and homocysteine (Hcy) mediated dopaminergic neurotoxicity is a matter of concern in the pathophysiology of Parkinson's disease (PD). Our previous study established the involvement of oxidative stress in the substantia nigra (SN) of Hcy rat model of PD; however, the role of antioxidants, such as melatonin, was not tested in this model.

MAIN METHODS

Melatonin (10, 20 and 30mg/kg, i.p.) was administered to rats injected with Hcy in right SN (1.0μmol in 2μl saline) to investigate its potency in attenuating the behavioral abnormalities, dopamine depletion and oxidative stress prompted by Hcy.

KEY FINDINGS

Treatment of melatonin protected against nigral dopamine loss and replenished the striatal dopamine loss that resulted in amelioration of rotational behavioral bias in Hcy denervated animals. Melatonin administration significantly improved mitochondrial complex-I activity and protected the SN neurons from the toxic insults of oxidative stress induced by Hcy. Amelioration of oxidative stress by melatonin in Hcy-infused SN was bought by dose-dependently scavenging of hydroxyl radicals, restoration of glutathione level and elevation in the activity of antioxidant enzymes.

SIGNIFICANCE

The observations bring into light the significant neuroprotective potentials of melatonin in Hcy model of PD which is attributed to the attenuation of oxidative stress in SN.

Oxazepam-Dopamine Conjugates Increase Dopamine Delivery into Striatum of Intact Rats

The neurotransmitter dopamine (DA) was covalently linked to oxazepam (OXA), a well-known positive allosteric modulator of γ-aminobutyric acid type-A (GABA_A) receptor, through a carbamate linkage (4) or a succinic spacer (6). These conjugates were synthesized with the aim of improving the delivery of DA into the brain and enhancing GABAergic transmission, which may be useful for the long-term treatment of Parkinson disease (PD). Structure-based permeability properties, in vitro stability, and blood-brain barrier (BBB) permeability studies led to identify the OXA-DA carbamate conjugate 4a as the compound better combining sufficient stability and ability to cross BBB. Finally, in vivo microdialysis experiments in freely moving rats demonstrated that 4a (20 mg/kg, i.p.) significantly increases extracellular DA levels into striatum, with a peak (more than 15-fold increase over the baseline) at about 80 min after a single administration. The stability and delivery data proved that 4a may be a promising candidate for further pharmacological studies in animal models of PD.

Mitochondrial impairment and melatonin protection in parkinsonian mice do not depend of inducible or neuronal nitric oxide synthases

MPTP-mouse model constitutes a well-known model of neuroinflammation and mitochondrial failure occurring in Parkinson’s disease (PD). Although it has been extensively reported that nitric oxide (NO^●) plays a key role in the pathogenesis of PD, the relative roles of nitric oxide synthase isoforms iNOS and nNOS in the nigrostriatal pathway remains, however, unclear. Here, the participation of iNOS/nNOS isoforms in the mitochondrial dysfunction was analyzed in iNOS and nNOS deficient mice. Our results showed that MPTP increased iNOS activity in substantia nigra and striatum, whereas it sharply reduced complex I activity and mitochondrial bioenergetics in all strains. In the presence of MPTP, mice lacking iNOS showed similar restricted mitochondrial function than wild type or mice lacking nNOS. These results suggest that iNOS-dependent elevated nitric oxide, a major pathological hallmark of neuroinflammation in PD, does not contribute to mitochondrial impairment. Therefore, neuroinflammation and mitochondrial dysregulation seem to act in parallel in the MPTP model of PD. Melatonin administration, with well-reported neuroprotective properties, counteracted these effects, preventing from the drastic changes in mitochondrial oxygen consumption, increased NOS activity and prevented reduced locomotor activity induced by MPTP. The protective effects of melatonin on mitochondria are also independent of its anti-inflammatory properties, but both effects are required for an effective anti-parkinsonian activity of the indoleamine as reported in this study.

Chronic low-dose melatonin treatment maintains nigrostriatal integrity in an intrastriatal rotenone model of Parkinson's disease

Parkinson's disease is a major neurodegenerative disorder which primarily involves the loss of dopaminergic neurons in the substantia nigra and related projections in the striatum. The pesticide/neurotoxin, rotenone, has been shown to cause systemic inhibition of mitochondrial complex I activity in nigral dopaminergic neurons, with consequent degeneration of the nigrostriatal pathway, as observed in Parkinson's disease. A novel intrastriatal rotenone model of Parkinson's disease was used to examine the neuroprotective effects of chronic low-dose treatment with the antioxidant indoleamine, melatonin, which can upregulate neurotrophic factors and other protective proteins in the brain. Sham or lesioned rats were treated with either vehicle (0.04% ethanol in drinking water) or melatonin at a dose of 4 µg/mL in drinking water. The right striatum was lesioned by stereotactic injection of rotenone at three sites (4 μg/site) along its rostrocaudal axis. Apomorphine administration to lesioned animals resulted in a significant (p<0.001) increase in ipsilateral rotations, which was suppressed by melatonin. Nine weeks post-surgery, animals were sacrificed by transcardial perfusion. Subsequent immunohistochemical examination revealed a decrease in tyrosine hydroxylase immunoreactivity within the striatum and substantia nigra of rotenone-lesioned animals. Melatonin treatment attenuated the decrease in tyrosine hydroxylase in the striatum and abolished it in the substantia nigra. Stereological cell counts indicated a significant (p<0.05) decrease in dopamine neurons in the substantia nigra of rotenone-lesioned animals, which was confirmed by Nissl staining. Importantly, chronic melatonin treatment blocked the loss of dopamine neurons in rotenone-lesioned animals. These findings strongly support the therapeutic potential of long-term and low-dose melatonin treatment in Parkinson's disease.

Piroxicam-mediated modulatory action of 5-hydroxytryptamine serves as a "brake" on neuronal excitability in ischemic stroke

Our previous studies indicated an increase in extracellular γ-aminobutyric acid (GABA) in rodent's ischemic brain after Piroxicam administration, leading to alleviation of glutamate mediated excitotoxicity through activation of type A GABA receptor (GABAA). This study was to investigate if GABAA activation by Piroxicam affects extracellular 5-hydroxytryptamine or not. High performance liquid chromatography revealed that there was a significant decrease in extracellular 5-hydroxytryptamine release in ischemic cerebral cortex and striatum in Piroxicam pre-treated rat brains. This suggests a probable role of Piroxicam in reducing extracellular 5-hydroxytryptamine release in ischemic cerebral cortex and striatum possibly due to the GABAA activation by Piroxicam.

The potential physiological crosstalk and interrelationship between two sovereign endogenous amines, melatonin and homocysteine

The antioxidant melatonin and the non-proteinogenic excitotoxic amino acid homocysteine (Hcy) are very distinct but related reciprocally to each other in their mode of action. The elevated Hcy level has been implicated in several disease pathologies ranging from cardio- and cerebro-vascular diseases to neurodegeneration owing largely to its free radical generating potency. Interestingly, melatonin administration potentially normalizes the elevated Hcy level, thereby protecting the cells from the undesired Hcy-induced excitotoxicity and cell death. However, the exact mechanism and between them remain obscure. Through literature survey we have found an indistinct but a vital link between melatonin and Hcy i.e., the existence of reciprocal regulation between them, and this aspect has been thoroughly described herein. In this review, we focus on all the possibilities of co-regulation of melatonin and Hcy at the level of their production and metabolism both in basal and in pathological conditions, and appraised the potential of melatonin in ameliorating homocysteinemia-induced cellular stresses. Also, we have summarized the differential mode of action of melatonin and Hcy on health and disease states.

Cholesterol - A putative endogenous contributor towards Parkinson's disease

Elevated levels of cholesterol and its metabolites (oxysterols) have been reported to be associated not only with several metabolic syndromes, but also become a prognostic risk factor of neurodegenerative diseases particularly Alzheimer's disease. The incidence and the prospect of Alzheimer's disease with respect to elevated levels of cholesterol have been studied extensively and reviewed earlier. Recently, several interesting findings have shown the occurrence of equivalent Parkinsonian pathologies in cellular neuronal models, mediated by oxysterols or excess exposure to cholesterol. In this regard, oxysterols are particular in causing alpha-synuclein aggregation and destruction of dopamine containing neurons in in vitro models, which is linked to their direct influence on oxidative stress provoking potency. Inspite of the significant in vitro reports, which suggest the relativeness of cholesterol or oxysterol towards Parkinsonism, several prospective clinical reports provided a negative or no correlation. However, few prospective clinical studies showed a positive correlation between plasma cholesterol and incidence of Parkinson's disease (PD). Also, few significant studies have convincingly demonstrated that high fat diet exacerbates parkinsonian pathologies, including loss of dopaminergic neurons and oxidative stress parameters in animal models of PD. The present review brings together all the neuropathological proceedings mediated by excess cholesterol or its metabolites in brain in the light of their contribution towards the onset of PD. Also we have reviewed the possibilities of cholesterol lowering efficacy of statin therapy, in reducing the occurrence of PD.

Melatonin enhances L-DOPA therapeutic effects, helps to reduce its dose, and protects dopaminergic neurons in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice

L-3,4-dihydroxyphenylalanine (L-DOPA) reduces symptoms of Parkinson's disease (PD), but suffers from serious side effects on long-term use. Melatonin (10-30 mg/kg, 6 doses at 10 hr intervals) was investigated to potentiate L-DOPA therapeutic effects in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism in mice. Striatal tyrosine hydroxylase (TH) immunoreactivity, TH, and phosphorylated ser 40 TH (p-TH) protein levels were assayed on 7th day. Nigral TH-positive neurons stereology was conducted on serial sections 2.8 mm from bregma rostrally to 3.74 mm caudally. MPTP caused 39% and 58% decrease, respectively, in striatal fibers and TH protein levels, but 2.5-fold increase in p-TH levels. About 35% TH neurons were lost between 360 and 600 μm from 940 μm of the entire nigra analyzed, but no neurons were lost between 250 μm rostrally and 220 μm caudally. When L-DOPA in small doses (5-8 mg/kg) failed to affect MPTP-induced akinesia or catalepsy, co-administration of melatonin with L-DOPA attenuated these behaviors. Melatonin administration significantly attenuated MPTP-induced loss in striatal TH fibers (82%), TH (62%) and p-TH protein (100%) levels, and nigral neurons (87-100%). Melatonin failed to attenuate MPTP-induced striatal dopamine depletion. L-DOPA administration (5 mg/kg, once 40 min prior to sacrifice, p.o.) in MPTP- and melatonin-treated mice caused significant increase in striatal dopamine (31%), as compared to L-DOPA and MPTP-treated mice. This was equivalent to 8 mg/kg L-DOPA administration in parkinsonian mouse. Therefore, prolonged, effective use of L-DOPA in PD with lesser side effects could be achieved by treating with 60% lower doses of L-DOPA along with melatonin.

Effects of endogenous melatonin on glutamate and GABA rhythms in the striatum of unilateral 6-hydroxydopamine-lesioned rats

We have previously reported a time-dependent increase in melatonin (MLT) and decrease in dopamine (DA) in striatal dialysate 3 weeks after unilateral 6-hydroxydopamine (6-OHDA) lesioning in the rat substantia nigra pars compacta (SNc) and medial forebrain bundle (MFB). This study aimed to investigate dynamic and circadian variations in DA, MLT, glutamate (Glu) and γ-aminobutyric acid (GABA) in striatal dialysates in the same 6-OHDA animal model. These neurotransmitters were determined using high-performance liquid chromatography (HPLC). Three weeks following 6-OHDA lesioning, there was a significant increase in extracellular Glu (156%) and decrease in GABA (15%) and DA (85%) in the lesioned striatum. These changes continued over time. Concomitantly, MLT was increased by 107% in the lesioned striatal dialysates after 4 weeks, and continued to increase gradually over time. Six weeks post-treatment, levels of MLT secretion at 12 time points were higher, and the peak time of MLT secretion was earlier, in 6-OHDA-lesioned rats compared with vehicle-treated rats. In addition, significant variations in extracellular levels of Glu and GABA between day and night were observed in vehicle-treated rat striatum. However, no circadian variations were observed in the striatum of unilateral 6-OHDA-lesioned rats. Six weeks post-treatment, MLT levels correlated well with Glu and GABA levels at corresponding time-points in the striatum ipsilateral to the injected side in both groups, and increased MLT levels also correlated well with changes in Glu and GABA in the striatum in 6-OHDA-lesioned rats. These data suggest that 6-OHDA lesioning affects the endogenous productions of DA, MLT, Glu and GABA, and changes the MLT secretion pattern. Augmented striatal MLT levels and advanced MLT secretion pattern caused by unilateral intracerebral injection of 6-OHDA may influence the variations in Glu and GABA between day and night.

Hydroxyl radical reactions and the radical scavenging activity of β-carboline alkaloids

β-Carbolines are bioactive pyridoindole alkaloids occurring in foods, plants and the human body. Their activity as hydroxyl radical (OH) scavengers is reported here by using three different methods: deoxyribose degradation, hydroxylation of benzoate and hydroxylation of 2'-deoxyguanosine to give 8-hydroxy-2'-deoxyguanosine (8-OHdG) as assessed by RP-HPLC (MS). Fenton reactions (Fe(2+)/Fe(3+) plus H2O2) were used for OH generation, and the radical increased in the presence of ascorbic acid or 6-hydroxydopamine as pro-oxidants. β-Carbolines were scavengers of OH in the three assays and in the presence of pro-oxidants. Tetrahydro-β-carboline-3-carboxylic acids were active against the hydroxylation of 2'-deoxyguanosine. β-Carbolines reacted with hydroxyl radicals (OH) affording hydroxy-β-carbolines, whereas tetrahydro-β-carbolines gave oxidative and degradation products. On the basis of IC50 and reaction rates (k), β-carbolines (norharman and harman), and tetrahydro-β-carbolines (tetrahydro-β-carboline, 1-methyltetrahydro-β-carboline and pinoline) were good OH radical scavengers and their activity was comparable to that of the indole, melatonin, which is an effective hydroxyl radical scavenger and antioxidant.

Melatonin inhibits manganese-induced motor dysfunction and neuronal loss in mice: involvement of oxidative stress and dopaminergic neurodegeneration

Excessive manganese (Mn) induces oxidative stress and dopaminergic neurodegeneration. However, the relationship between them during Mn neurotoxicity has not been clarified. The purpose of this study was to investigate the probable role of melatonin (MLT) against Mn-induced motor dysfunction and neuronal loss as a result of antagonizing oxidative stress and dopaminergic neurodegeneration. Mice were randomly divided into five groups as follows: control, MnCl2, low MLT + MnCl2, median MLT + MnCl2, and high MLT + MnCl2. Administration of MnCl2 (50 mg/kg) for 2 weeks significantly induced hypokinesis, dopaminergic neurons degeneration and loss, neuronal ultrastructural damage, and apoptosis in the substantia nigra and the striatum. These conditions were caused in part by the overproduction of reactive oxygen species, malondialdehyde accumulation, and dysfunction of the nonenzymatic (GSH) and enzymatic (GSH-Px, superoxide dismutase, quinone oxidoreductase 1, glutathione S-transferase, and glutathione reductase) antioxidative defense systems. Mn-induced neuron degeneration, astrocytes, and microglia activation contribute to the changes of oxidative stress markers. Dopamine (DA) depletion and downregulation of DA transporter and receptors were also found after Mn administration, this might also trigger motor dysfunction and neurons loss. Pretreatment with MLT prevented Mn-induced oxidative stress and dopaminergic neurodegeneration and inhibited the interaction between them. As a result, pretreatment with MLT significantly alleviated Mn-induced motor dysfunction and neuronal loss. In conclusion, Mn treatment resulted in motor dysfunction and neuronal loss, possibly involving an interaction between oxidative stress and dopaminergic neurodegeneration in the substantia nigra and the striatum. Pretreatment with MLT attenuated Mn-induced neurotoxicity by means of its antioxidant properties and promotion of the DA system.

Protective effects of Althaea officinalis L. extract in 6-hydroxydopamine-induced hemi-Parkinsonism model: behavioral, biochemical and histochemical evidence

It is well known that Parkinson's disease (PD) is the second most common neurodegenerative disorder in humans. In this regard, the neuroprotective effect of Althaea officinalis (AO) has already been reported. Therefore, this study examined whether administration of AO extract would improve behavioral, biochemical and structural abnormalities in an experimental animal model of PD in rats. For this purpose, we induced hemi-Parkinsonism by unilateral intranigral injection of 6-hydroxydopamine (6-OHDA, 8 μg/5 μl saline-ascorbate). The rats were pretreated i.p. with AO extract (10 mg/kg) started 6 days before surgery and continued until the 3rd day post-surgery. Regarding oxidative stress, brain MDA concentration (as a lipid peroxidation marker) increased significantly in the 6-OHDA-administered group in comparison with rats pretreated with AO extract. It was found that AO treatment attenuated rotational behavior in the 6-OHDA-administered group and protected the neurons of substantia nigra pars compacta against 6-OHDA toxicity. Overall, AO extract administration indicated neuroprotective effects against 6-OHDA-induced hemi-Parkinsonism in rats.

Serum melatonin is an alternative index of Parkinson's disease severity

The protective potential of melatonin (MLT) in Parkinson's disease (PD) is the subject of considerable controversy. The purpose of the present study was to investigate serum MLT levels in unilateral 6-hydroxydopamine (6-OHDA) lesion rats and patients with PD. Blood samples were collected from rats at 10:00 am and from patients with PD and healthy subjects between 8:00 and 10:00 am. Serum MLT levels were measured using the enzyme-linked immunosorbent assay. Our results revealed that the morning serum MLT levels either in 6-OHDA-induced hemi-parkinsonian rats or patients with PD were significantly higher than that of control group. Our results also demonstrate that serum MLT levels are correlated with severity of PD according to H & Y scale.

Neuroprotective potential of silymarin against CNS disorders: insight into the pathways and molecular mechanisms of action

Silymarin, a C25 containing flavonoid from the plant Silybum marianum, has been the gold standard drug to treat liver disorders associated with alcohol consumption, acute and chronic viral hepatitis, and toxin-induced hepatic failures since its discovery in 1960. Apart from the hepatoprotective nature, which is mainly due to its antioxidant and tissue regenerative properties, Silymarin has recently been reported to be a putative neuroprotective agent against many neurologic diseases including Alzheimer's and Parkinson's diseases, and cerebral ischemia. Although the underlying neuroprotective mechanism of Silymarin is believed to be due to its capacity to inhibit oxidative stress in the brain, it also confers additional advantages by influencing pathways such as β-amyloid aggregation, inflammatory mechanisms, cellular apoptotic machinery, and estrogenic receptor mediation. In this review, we have elucidated the possible neuroprotective effects of Silymarin and the underlying molecular events, and suggested future courses of action for its acceptance as a CNS drug for the treatment of neurodegenerative diseases.

Melatonin suppresses nitric oxide production in glial cultures by pro-inflammatory cytokines through p38 MAPK inhibition

Melatonin has been shown to down-regulate inflammatory responses and provide neuroprotection. However, the mechanisms underlying the anti-inflammatory properties of melatonin are poorly understood. In the present work, we studied the modulatory effect of melatonin against pro-inflammatory cytokines in glial cell cultures. Treatment with pro-inflammatory cytokines mainly tumor necrosis factor-alpha, interleukin 1-beta, and interferon-gamma induces an increase in inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production. Pre-treatment with melatonin produced an inhibitory effect on iNOS expression and NO production. The biochemical studies revealed that cytokine treatment favors the activation of several pathways, such as mitogen-activated protein kinases (MAPKs), STAT1, and STAT3; however, the anti-inflammatory effect of melatonin was accompanied only by a decrease in p38 MAPK activity. Likewise, SB203580 a p38 kinase inhibitor inhibits NO production. These data indicate that the anti-inflammatory action of melatonin in glial cells after stimulation with pro-inflammatory cytokines may be in part, attributable to p38 inhibition which down-regulates iNOS expression and NO production.

Melatonin synergizes with low doses of L-DOPA to improve dendritic spine density in the mouse striatum in experimental Parkinsonism

The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-DOPA), is the preferred drug for Parkinson's disease, but long-term treatment results in the drug-induced dyskinesias and other side effects. This study was undertaken to examine whether melatonin could potentiate low dose L-DOPA effects in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental parkinsonism. Mice were treated with the parkinsonian neurotoxin, MPTP, and different doses of melatonin and low doses of L-DOPA. Behavior, striatal histology, and dopamine metabolism were evaluated on the 7th day. MPTP-induced striatal dopamine loss was not modified by melatonin administration (10-30 mg/kg; i.p. at 10-hr intervals, 6 times; or at 2-hr intervals, by day). However, low doses of L-DOPA (5 mg/kg, by oral gavage) administered alone or along with melatonin (10 mg/kg, i.p.) twice everyday for 2 days, 10 hr apart, after two doses of MPTP significantly attenuated striatal dopamine loss and provided improvements in both catalepsy and akinesia. Additionally, Golgi-impregnated striatal sections showed preservation of the medium spiny neurons, which have been damaged in MPTP-treated mouse. The results demonstrated that melatonin, but not L-DOPA, restored spine density and spine morphology of medium spiny neurons in the striatum and suggest that melatonin could be an ideal adjuvant to L-DOPA therapy in Parkinson's disease, and by the use of this neurohormone, it is possible to bring down the therapeutic doses of L-DOPA.

Contribution of β-phenethylamine, a component of chocolate and wine, to dopaminergic neurodegeneration: implications for the pathogenesis of Parkinson's disease

While the cause of dopaminergic neuronal cell death in Parkinson's disease (PD) is not yet understood, many endogenous molecules have been implicated in its pathogenesis. β-phenethylamine (β-PEA), a component of various food items including chocolate and wine, is an endogenous molecule produced from phenylalanine in the brain. It has been reported recently that long-term administration of β-PEA in rodents causes neurochemical and behavioral alterations similar to that produced by parkinsonian neurotoxins. The toxicity of β-PEA has been linked to the production of hydroxyl radical ((·)OH) and the generation of oxidative stress in dopaminergic areas of the brain, and this may be mediated by inhibition of mitochondrial complex-I. Another significant observation is that administration of β-PEA to rodents reduces striatal dopamine content and induces movement disorders similar to those of parkinsonian rodents. However, no reports are available on the extent of dopaminergic neuronal cell death after administration of β-PEA. Based on the literature, we set out to establish β-PEA as an endogenous molecule that potentially contributes to the progressive development of PD. The sequence of molecular events that could be responsible for dopaminergic neuronal cell death in PD by consumption of β-PEA-containing foods is proposed here. Thus, long-term over-consumption of food items containing β-PEA could be a neurological risk factor having significant pathological consequences.

Increased melatonin may play dual roles in the striata of a 6-hydroxydopamine model of Parkinson's disease

AIMS

To investigate dynamic changes and roles of melatonin (MLT) in the striata of 6-hydroxydopamine (6-OHDA)-treated rats.

MAIN METHODS

A Parkinson's disease (PD) rat was established by a unilateral injection of 6-OHDA into the right substantia nigra pars compacta (SNc) and the right medial forebrain bundle (MFB) to achieve a complete lesion of the ipsilateral nigrostriatal DA system. Dialysates were collected in the lesioned striatum at different time intervals by in vivo microdialysis. In addition, both contralateral and ipsilateral striatum tissues were collected at two time intervals (10:00 and 22:00 h) at 3 and 6 weeks after lesioning. The levels of DA, 3, 4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the dialysates, as well as MLT in the dialysates and tissues were determined using HPLC.

KEY FINDINGS

The dialysate contents of DA, DOPAC and HVA in the lesioned striatum were significantly decreased (P<0.001) in comparison with those in the controls or in the unlesioned side 3 weeks after lesioning while the extracellular level of MLT in the lesioned striatum in these corresponding time intervals distinctly increased when compared with those in the controls (P<0.05). The tissue MLT contents increased in the bilateral striata in different degrees at 6 weeks post-lesion (P<0.05). Moreover, increased MLT levels correlate well with rotations or DA changes in the lesioned striatum.

SIGNIFICANCE

These data suggest that 6-OHDA lesion manipulates the MLT secretion pattern. Increased striatal MLT level by a unilateral intracerebral injection of 6-OHDA may play dual roles in the progression of PD in rats.

Effect of chronic L-dopa or melatonin treatments after dopamine deafferentation in rats: dyskinesia, motor performance, and cytological analysis

The present study examines the ability of melatonin to protect striatal dopaminergic loss induced by 6-OHDA in a rat model of Parkinson's disease, comparing the results with L-DOPA-treated rats. The drugs were administered orally daily for a month, their therapeutic or dyskinetic effects were assessed by means of abnormal involuntary movements (AIMs) and stepping ability. At the cellular level, the response was evaluated using tyrosine hydroxylase immunoreactivity and striatal ultrastructural changes to compare between L-DOPA-induced AIMs and Melatonin-treated rats. Our findings demonstrated that chronic oral administration of Melatonin improved the alterations caused by the neurotoxin 6-OHDA. Melatonin-treated animals perform better in the motor tasks and had no dyskinetic alterations compared to L-DOPA-treated group. At the cellular level, we found that Melatonin-treated rats showed more TH-positive neurons and their striatal ultrastructure was well preserved. Thus, Melatonin is a useful treatment to delay the cellular and behavioral alterations observed in Parkinson's disease.

Melatonin as a neuroprotective agent in the rodent models of Parkinson's disease: is it all set to irrefutable clinical translation?

Parkinson's disease (PD), a neurodegenerative disorder, is characterized by the selective degeneration of the nigrostriatal dopaminergic neurons, continuing or permanent deficiency of dopamine, accretion of an abnormal form of alpha synuclein in the adjacent neurons, and dysregulation of ubiquitin proteasomal system, mitochondrial metabolism, permeability and integrity, and cellular apoptosis resulting in rigidity, bradykinesia, resting tremor, and postural instability. Melatonin, an indoleamine produced almost in all the organisms, has anti-inflammatory, anti-apoptotic, and anti-oxidant nature. Experimental studies employing 1-methyl 4-phenyl 1, 2, 3, 6-tetrahydropyridine (MPTP), 6-hydroxydopamine (6-OHDA), methamphetamine, rotenone, and maneb and paraquat models have shown an enormous potential of melatonin in amelioration of the symptomatic features of PD. Although a few reviews published previously have described the multifaceted efficacy of melatonin against MPTP and 6-OHDA rodent models, due to development and validation of the newer models as well as the extensive studies on the usage of melatonin in entrenched PD models, it is worthwhile to bring up to date note on the usage of melatonin as a neuroprotective agent in PD. This article presents an update on the usage and applications of melatonin in PD models along with incongruous observations. The impending implications in the clinics, success, limitations, and future prospective have also been discussed in this article.

Therapeutic potential of melatonin and its analogs in Parkinson's disease: focus on sleep and neuroprotection

Sleep disorders constitute major nonmotor features of Parkinson's disease (PD) that have a substantial effect on patients' quality of life and can be related to the progression of the neurodegenerative disease. They can also serve as preclinical markers for PD, as it is the case for rapid eye movement (REM)-associated sleep behavior disorder (RBD). Although the etiology of sleep disorders in PD remains undefined, the assessment of the components of the circadian system, including melatonin secretion, could give therapeutically valuable insight on their pathophysiopathology. Melatonin is a regulator of the sleep/wake cycle and also acts as an effective antioxidant and mitochondrial function protector. A reduction in the expression of melatonin MT(1) and MT(2) receptors has been documented in the substantia nigra of PD patients. The efficacy of melatonin for preventing neuronal cell death and for ameliorating PD symptoms has been demonstrated in animal models of PD employing neurotoxins. A small number of controlled trials indicate that melatonin is useful in treating disturbed sleep in PD, in particular RBD. Whether melatonin and the recently developed melatonergic agents (ramelteon, tasimelteon, agomelatine) have therapeutic potential in PD is also discussed.

The presence of melatonin in grapevine (Vitis vinifera L.) berry tissues

Melatonin has been reported in a variety of food plants and, consequently, in a number of plant-derived foodstuffs. In grapevine (Vitis vinifera L.) products, it was found in berry exocarp (skin) of different cultivars and monovarietal wines. Herein, we assessed, by means of mass spectrometry, the occurrence of melatonin in all berry tissues (skin, flesh, and seed) at two different phenological stages, pre-véraison and véraison. We detected the highest melatonin content in skin, at pre-véraison, whereas, at véraison, the highest levels were reported in the seed. Furthermore, during ripening, melatonin decreased in skin, while increasing in both seed and flesh. The relative concentrations of melatonin in diverse berry tissues were somewhat different from those of total polyphenols (TP), the latter measured by the Folin-Ciocalteau assay, and more abundant in seed at pre-véraison and in exocarp at véraison. The highest antiradical activity, determined by both DPPH (2,2-diphenyl-1-pycryl hydrazyl) and ABTS [(2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] radical-scavenging assay, was reported at pre-veráison in seed. To the best of our knowledge, we reported, for the first time, the occurrence of melatonin in grape seeds.

Protective effect of melatonin on 3-NP induced striatal interneuron injury in rats

To confirm the effect of melatonin on 3-nitropropionic acid (3-NP)-induced striatal interneuron injury in rats, behavioral test, histology, immunohistochemistry and Western blotting were respectively used to characterize the behavioral changes of experimental animals in motor and cognition, the morphological changes of striatal interneurons and the expression level of protein markers induced by 3-NP. The results showed that (1) 3-NP induced dysfunction of experimental animals in movement, motor coordination and cognition could be relieved by melatonin treatment; (2) The 3-NP-induced lesion area was unvaryingly in dorsolateral striatum, with almost all neuronal loss in the lesion core, however, lots of neurons survived after melatonin treatment; (3) Immunohistochemical staining of the four interneuron types (parvalbuminergic, cholinergic, calretinergic, and neuropeptide Y-neuronal nitric oxide synthase co-containing) showed that, in the lesion core of 3-NP group, loss of the four interneuron types was obvious, but in transition zone, the processes and varicosities of calretinergic, and neuropeptide Y-neuronal nitric oxide synthase co-containing interneurons increased significantly. Melatonin treatment reduced the loss of the four interneuron types in the lesion core, and inhibited the increase of processes and varicosities in the transition zone; (4) Consistent with above results, the expression level of five interneuron protein markers were significantly increased in the striatum after melatonin treatment. Notably, in both the transition zone and the lesion core induced by 3-NP, TUNEL-positive cells were detected, but decreased significantly after melatonin treatment. The present results indicate that melatonin effectively protects the striatal neurons against the injury induced by 3-NP in rats.

A new perspective in Oral health: potential importance and actions of melatonin receptors MT1, MT2, MT3, and RZR/ROR in the oral cavity

BACKGROUND

Melatonin is involved in many physiological processes in mammals, amongst others; it is implicated in sleep-wake regulation. It has antioxidant and anti-inflammatory properties. It also acts as an immunomodulator, stimulates bone metabolism and inhibits various tumours. Additionally an abnormal melatonin rhythm may contribute to depression and insomnia. The mechanisms of action of melatonin include the involvement of membrane receptors (MT1, MT2), cytosolic binding sites (MT3 and calmodulin), and nuclear receptors of the RZR/ROR family. Melatonin also has receptor-independent activity and can directly scavenge free radicals. The current review addresses the functions of melatonin in the oral cavity in relation to its receptors.

METHODS

An extensive search was conducted on the following scientific databases Pub Med, Science Direct, ISI Web of Knowledge and Cochrane database in order to review all pertinent literature.

RESULTS

Melatonin from the blood into the saliva may play an important role in suppressing oral diseases. It may have beneficial effects in periodontal disease, herpes and oral cancer, amongst others.

CONCLUSIONS

Melatonin contributes to protecting of oral cavity from tissue damage due to its action of different receptors. From the reviewed literature it is concluded that experimental evidence suggests that melatonin can be useful in treating several common diseases of the oral cavity. Specific studies are necessary to extend the therapeutic possibilities of melatonin to other oral diseases.

Melatonin or silymarin reduces maneb- and paraquat-induced Parkinson's disease phenotype in the mouse

Oxidative stress is reported as one of the most widely accepted mechanisms of maneb (MB)- and paraquat (PQ)-induced nigrostriatal dopaminergic neurodegeneration leading to the Parkinson's disease (PD) phenotype. The study investigated the effects of silymarin, an antioxidant of plant origin, and melatonin, an indoleamine produced in all species, in MB- and PQ-induced mouse model of PD. The mice were treated intraperitoneally daily with silymarin (40mg/kg) or melatonin (30mg/kg) along with respective controls for 9wk. Subsets of these animals were also treated with MB (30mg/kg) and PQ (10mg/kg), twice a week, for 9wk, 2hr after silymarin/melatonin treatment. Locomotor activities along with striatal dopamine content, tyrosine hydroxylase (TH) immunoreactivity, number of degenerating neurons, lipid peroxidation and nitrite content were estimated. Additionally, mRNA expression of vesicular monoamine transporter, cytochrome P-450 2E1 (CYP2E1), and glutathione-S-transferase A4-4 (GSTA4-4), catalytic activities of CYP2E1 and GSTA4-4 and protein expressions of unphosphorylated and phosphorylated p53 (p53 and P-p53), Bax and caspase 9 were measured in control and MB- and PQ-treated mice with either silymarin or melatonin treatments. Silymarin/melatonin significantly offset MB- and PQ-mediated reductions in locomotor activities, dopamine content, TH immunoreactivity, VMAT 2 mRNA expression and the expression of p53 protein. Silymarin/melatonin attenuated the increases in lipid peroxidation, number of degenerating neurons, nitrite content, mRNA expressions of cytochrome P-450 2E1 (CYP2E1) and GSTA4-4, catalytic activities of CYP2E1 and GST and P-p53, Bax and caspase 9 protein expressions. The results demonstrate that silymarin and melatonin offer nigrostriatal dopaminergic neuroprotection against MB- and PQ-induced PD by the modulation of oxidative stress and apoptotic machinery.

Cluster headache patients are not affected by restless legs syndrome: an observational study

OBJECTIVE

To investigate the presence of Restless Legs Syndrome (RLS) in Cluster Headache (CH) patients compared to headache-free controls.

DESIGN AND SETTING

Cross-sectional case-control study of CH patients presenting at tertiary headache centers over the period January-December 2008.

PATIENTS AND PARTICIPANTS

Fifty consecutive patients (6 women and 44 men) of mean age of 39.7 year (standard deviation 10.9) with episodic or chronic CH diagnosed according to ICHD-II criteria and 50 headache-free subjects matched by age and sex were recruited.

RESULTS

None of the CH patients had RLS. Six (12%) headache-free controls had RLS.

CONCLUSIONS

Our data indicate no probable relationship between CH and RLS. However, since both conditions have a circadian rhythm and are associated with altered melatonin secretion, we conjecture that reduced nocturnal melatonin in CH likely allows sustained dopaminergic activity which could be protective against RLS in CH patients.

The biochemical and cellular basis for nutraceutical strategies to attenuate neurodegeneration in Parkinson's disease

Future therapeutic intervention that could effectively decelerate the rate of degeneration within the substantia nigra pars compacta (SNc) could add years of mobility and reduce morbidity associated with Parkinson’s disease (PD). Neurodegenerative decline associated with PD is distinguished by extensive damage to SNc dopaminergic (DAergic) neurons and decay of the striatal tract. While genetic mutations or environmental toxins can precipitate pathology, progressive degenerative succession involves a gradual decline in DA neurotransmission/synaptic uptake, impaired oxidative glucose consumption, a rise in striatal lactate and chronic inflammation. Nutraceuticals play a fundamental role in energy metabolism and signaling transduction pathways that control neurotransmission and inflammation. However, the use of nutritional supplements to slow the progression of PD has met with considerable challenge and has thus far proven unsuccessful. This review re-examines precipitating factors and insults involved in PD and how nutraceuticals can affect each of these biological targets. Discussed are disease dynamics (Sections 1 and 2) and natural substances, vitamins and minerals that could impact disease processes (Section 3). Topics include nutritional influences on α-synuclein aggregation, ubiquitin proteasome function, mTOR signaling/lysosomal-autophagy, energy failure, faulty catecholamine trafficking, DA oxidation, synthesis of toxic DA-quinones, o-semiquinones, benzothiazolines, hyperhomocyseinemia, methylation, inflammation and irreversible oxidation of neuromelanin. In summary, it is clear that future research will be required to consider the multi-faceted nature of this disease and re-examine how and why the use of nutritional multi-vitamin-mineral and plant-based combinations could be used to slow the progression of PD, if possible.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Neurotoxins: free radical mechanisms and melatonin protection

Toxins that pass through the blood-brain barrier put neurons and glia in peril. The damage inflicted is usually a consequence of the ability of these toxic agents to induce free radical generation within cells but especially at the level of the mitochondria. The elevated production of oxygen and nitrogen-based radicals and related non-radical products leads to the oxidation of essential macromolecules including lipids, proteins and DNA. The resultant damage is referred to as oxidative and nitrosative stress and, when the molecular destruction is sufficiently severe, it causes apoptosis or necrosis of neurons and glia. Loss of brain cells compromises the functions of the central nervous system expressed as motor, sensory and cognitive deficits and psychological alterations. In this survey we summarize the publications related to the following neurotoxins and the protective actions of melatonin: aminolevulinic acid, cyanide, domoic acid, kainic acid, metals, methamphetamine, polychlorinated biphenyls, rotenone, toluene and 6-hydroxydopamine. Given the potent direct free radical scavenging activities of melatonin and its metabolites, their ability to indirectly stimulate antioxidative enzymes and their efficacy in reducing electron leakage from mitochondria, it would be expected that these molecules would protect the brain from oxidative and nitrosative molecular mutilation. The studies summarized in this review indicate that this is indeed the case, an action that is obviously assisted by the fact that melatonin readily crosses the blood brain barrier.

Melatonin in traditional Mediterranean diets

Compared with other industrialized countries, the lower incidence of chronic-degenerative disorders in Mediterranean populations has been emphasized in recent decades. The health-promoting effects arising from Mediterranean dietary habits have been attributed to the large intake of plant foodstuffs rich in bioactive phytochemicals, such as melatonin. Recently, it has been suggested that melatonin present in edible plants may improve human health, by virtue of its biological activities and its good bioavailability. Plant melatonin, besides contributing to optimize the physiological functions regulated, in humans, by endogenous melatonin, may be involved in nutritional therapy to reduce the risk of cancer, cardiovascular and neurodegenerative diseases in western populations. In this view, the presence of melatonin in some Mediterranean foods and beverages adds a new element to the hypothesis of health benefits associated to Mediterranean dietary patterns, although the available data are still preliminary and incomplete.

Melatonin, cardiolipin and mitochondrial bioenergetics in health and disease

Melatonin is a natural occurring compound with well-known antioxidant properties. Melatonin is ubiquitously distributed and because of its small size and amphiphilic nature, it is able to reach easily all cellular and subcellular compartments. The highest intracellular melatonin concentrations are found in mitochondria, raising the possibility of functional significance for this targeting with involvement in situ in mitochondrial activities. Mitochondria, the powerhouse of the cell, are considered to be the most important cellular organelles to contribute to degenerative processes mainly through respiratory chain dysfunction and formation of reactive oxygen species, leading to damage to mitochondrial proteins, lipids and DNA. Therefore, protecting mitochondria from oxidative damage could be an effective therapeutic strategy against cellular degenerative processes. Many of the beneficial effects of melatonin administration may depend on its effect on mitochondrial physiology. Cardiolipin, a phospholipid located at the level of inner mitochondrial membrane is known to be intimately involved in several mitochondrial bioenergetic processes as well as in mitochondrial-dependent steps of apoptosis. Alterations to cardiolipin structure, content and acyl chain composition have been associated with mitochondrial dysfunction in multiple tissues in several physiopathological situations and aging. Recently, melatonin was reported to protect the mitochondria from oxidative damage by preventing cardiolipin oxidation and this may explain, at least in part, the beneficial effect of this molecule in mitochondrial physiopathology. In this review, we discuss the role of melatonin in preventing mitochondrial dysfunction and disease.