Immediate and Delayed Treatments with Curcumin Prevents Forebrain Ischemia-Induced Neuronal Damage and Oxidative Insult in the Rat Hippocampus

Curcumin modulates astrocyte function under basal and inflammatory conditions

Curcumin is a pleiotropic molecule with well-known anti-inflammatory effects. This molecule has attracted attention due to its capacity to pass the blood-brain-barrier and modulate central nervous system (CNS) cells, such as astrocytes. Astrocytes are the most numerous CNS cells, and play a pivotal role in inflammatory damage, a common feature in neurodegenerative diseases such as Alzheimer's Disease. Although the actions of curcumin have been studied extensively in peripheral cells, few studies have investigated the effect of curcumin on astrocytes under basal and inflammatory conditions. The aim of this study was to characterize the effect of curcumin on astrocytic function (glutamatergic metabolism, GFAP and S100B), and investigate a possible synergic effect with another molecule, piperine. For this purpose, we used primary cultured astrocytes; our results showed that curcumin increases GSH and GFAP content, but decreases S100B secretion under basal conditions. Under inflammatory conditions, provoked by lipopolysaccharide (LPS), curcumin and piperine reversed the LPS-induced secretion of TNF-α, and piperine reverted the LPS-induced upregulation of GFAP content. Interestingly, curcumin decreases S100B secretion even more than LPS. These results highlight important context-dependent effects of curcumin and piperine on astrocytes. Although we did not observe synergic effects of co-treatment with curcumin and piperine, their effects were complementary, as piperine modulated GFAP content under inflammatory conditions, and curcumin modulated S100B secretion. Both curcumin and piperine had important anti-inflammatory actions in astrocytes. We herein provide new insights into the actions of curcumin in the CNS that may aid in the search for new molecular targets and possible treatments for neurological diseases.

Curcumin and targeting of molecular and metabolic pathways in multiple sclerosis

Multiple sclerosis (MS) is a life-threading disease that poses a great threat to the human being lifestyle. Having said extensive research in the realm of underlying mechanisms and treatment procedures, no definite remedy has been found. Over the past decades, many medicines have been disclosed to alleviate the symptoms and marking of MS. Meanwhile, the substantial efficacy of herbal medicines including curcumin must be underscored. Accumulated documents demonstrated the fundamental role of curcumin in the induction of the various signaling pathways. According to evidence, curcumin can play a role in mitochondrial dysfunction and apoptosis, autophagy, and mitophagy. Also, by targeting the signaling pathways AMPK, PGC-1α/PPARγ, and PI3K/Akt/mTOR, curcumin interferes with the metabolism of MS. The anti-inflammatory, antioxidant, and immune regulatory effects of this herbal compound are involved in its effectiveness against MS. Thus, the present review indicates the molecular and metabolic pathways associated with curcumin's various pharmacological actions on MS, as well as setting into context the many investigations that have noted curcumin-mediated regulatory effects in MS.

The action of curcumin against damage resulting from cerebral stroke: a systematic review

Stroke is the second leading cause of morbidity and mortality globally. Treatments for stroke are limited, and preventive treatments are scarce. Curcumin (CUR) has several biological effects, as described in the literature, which highlight its antioxidant and neuroprotective effects. Therefore, this qualitative systematic review aimed to investigate the effects of CUR on damage caused by stroke in rodent models. A systematic search was performed on three databases PubMed, Scopus, and Web of Science. In addition, the risk-of-bias and quality of the studies were assessed using SYRCLE and Collaborative Approach for Meta-Analysis and Review of Animal Data from Experimental Studies, respectively. The selection, inclusion, and exclusion criteria were established by the authors. At the end of our systematic search of the three databases, we found a total of 728 articles. After excluding duplicates and triplicates and reading the abstracts, keywords, and full texts, 53 articles were finally included in this systematic review. CUR exerts several beneficial effects against the damage caused by both ischemic and hemorrhagic stroke, via different pathways. However, because of its low bioavailability, Free-form CUR only exerted significant effects when it was administered at high concentrations. In contrast, when CUR was administered using nanostructured systems, positive responses were observed even at low concentrations. The mechanisms of action of CUR, free or in nanostructure, are extremely important for the recovery of injured brain tissue after a stroke; CUR has neuroprotective, antioxidant, anti-inflammatory, and anti-apoptotic effects and helps to maintain the integrity of the blood-brain barrier. Finally, we concluded that CUR presents an extremely important and significant response profile against the damage caused by stroke, making it a possible therapeutic candidate for individuals affected by this disease.

Mechanisms Underlying Curcumin-Induced Neuroprotection in Cerebral Ischemia

Ischemic stroke is the leading cause of death and disability worldwide, and restoring the blood flow to ischemic brain tissues is currently the main therapeutic strategy. However, reperfusion after brain ischemia leads to excessive reactive oxygen species production, inflammatory cell recruitment, the release of inflammatory mediators, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, and blood-brain barrier damage; these pathological mechanisms will further aggravate brain tissue injury, ultimately affecting the recovery of neurological functions. It has attracted the attention of researchers to develop drugs with multitarget intervention effects for individuals with cerebral ischemia. A large number of studies have established that curcumin plays a significant neuroprotective role in cerebral ischemia via various mechanisms, including antioxidation, anti-inflammation, anti-apoptosis, protection of the blood-brain barrier, and restoration of mitochondrial function and structure, restoring cerebral circulation, reducing infarct volume, improving brain edema, promoting blood-brain barrier repair, and improving the neurological functions. Therefore, summarizing the results from the latest literature and identifying the potential mechanisms of action of curcumin in cerebral ischemia will serve as a basis and guidance for the clinical applications of curcumin in the future.

γ-Glutamylcysteine Alleviates Ischemic Stroke-Induced Neuronal Apoptosis by Inhibiting ROS-Mediated Endoplasmic Reticulum Stress

Ischemic stroke is a severe and acute neurological disorder with limited therapeutic strategies currently available. Oxidative stress is one of the critical pathological factors in ischemia/reperfusion injury, and high levels of reactive oxygen species (ROS) may drive neuronal apoptosis. Rescuing neurons in the penumbra is a potential way to recover from ischemic stroke. Endogenous levels of the potent ROS quencher glutathione (GSH) decrease significantly after cerebral ischemia. Here, we aimed to investigate the neuroprotective effects of γ-glutamylcysteine (γ-GC), an immediate precursor of GSH, on neuronal apoptosis and brain injury during ischemic stroke. Middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R) were used to mimic cerebral ischemia in mice, neuronal cell lines, and primary neurons. Our data indicated that exogenous γ-GC treatment mitigated oxidative stress, as indicated by upregulated GSH and decreased ROS levels. In addition, γ-GC attenuated ischemia/reperfusion-induced neuronal apoptosis and brain injury in vivo and in vitro. Furthermore, transcriptomics approaches and subsequent validation studies revealed that γ-GC attenuated penumbra neuronal apoptosis by inhibiting the activation of protein kinase R-like endoplasmic reticulum kinase (PERK) and inositol-requiring enzyme 1α (IRE1α) in the endoplasmic reticulum (ER) stress signaling pathway in OGD/R-treated cells and ischemic brain tissues. To the best of our knowledge, this study is the first to report that γ-GC attenuates ischemia-induced neuronal apoptosis by suppressing ROS-mediated ER stress. γ-GC may be a promising therapeutic agent for ischemic stroke.

Systems Biology and Chemoinformatics-Based Strategies to Explore the Biological Mechanism of Fugui Wenyang Decoction in Treating Vascular Dementia Rats

OBJECTIVE

To explore the biological mechanism of Fugui Wenyang Decoction (FGWYD) in treating vascular dementia (VD) rats based on systems pharmacology, proteomics, and a multidirectional pharmacology integration strategy.

METHODS

Chemoinformatics was utilized to construct and analyze the FGWYD-VD protein-protein interaction (PPI) network. Then, the total protein in the brain tissue of the infarcted side of the rat was extracted for protein identification, pattern identification, and protein quantitative analysis. The differentially expressed proteins are analyzed by bioinformatics. Finally, the important proteins in the oxidative stress-related biological process proteins and indicators were detected through experimental pharmacology to verify the findings of systems biology and chemoinformatics.

RESULTS

There were a total of 73 FGWYD components with 245 FGWYD and 145 VD genes. The results of GO enrichment analysis and pathway enrichment analysis showed that MBHD may regulate the inflammation module, oxidative stress, the synaptic plasticity regulation module, and the neuronal apoptosis section module. Compared with the sham operation group, there were 23 upregulated proteins and 17 downregulated proteins in the model group (P < 0.05). Compared with the model group, there were 16 upregulated proteins and 10 downregulated proteins in the FGWYD group (P < 0.05). Bioinformatics analysis shows that those proteins were closely related to processes such as inflammation, oxidative stress, neuronal apoptosis, neuronal growth and differentiation, signaling pathways, and transcriptional regulation. Multidirectional pharmacology further verified the neuroprotective mechanism of the Nrf2/HO-1 pathway in FGWYD treatment of VD.

CONCLUSION

The mechanism of FGWYD in the treatment of VD may be related to inflammation, oxidative stress, angiogenesis, and neuronal apoptosis.

Neuroprotective Effects of Curcumin in Cerebral Ischemia: Cellular and Molecular Mechanisms

Despite being a major global health concern, cerebral ischemia/stroke has limited therapeutic options. Tissue plasminogen activator (tPA) is the only available medication to manage acute ischemic stroke, but this medication is associated with adverse effects and has a narrow therapeutic time window. Curcumin, a polyphenol that is abundantly present in the rhizome of the turmeric plant (Curcuma longa), has shown promising neuroprotective effects in animal models of neurodegenerative diseases, including cerebral ischemia. In the central nervous system (CNS), neuroprotective effects of curcumin have been experimentally validated in Alzheimer's disease, Parkinson's disease, multiple sclerosis, and cerebral ischemia. Curcumin can exert pleiotropic effects in the postischemic brain including antioxidant, anti-inflammatory, antiapoptotic, vasculoprotective, and direct neuroprotective efficacies. Importantly, neuroprotective effects of curcumin has been reported in both ischemic and hemorrhagic stroke models. A broad-spectrum neuroprotective efficacy of curcumin suggested that curcumin can be an appealing therapeutic strategy to treat cerebral ischemia. In this review, we aimed to address the pharmacotherapeutic potential of curcumin in cerebral ischemia including its cellular and molecular mechanisms of neuroprotection revealing curcumin as an appealing therapeutic candidate for cerebral ischemia.

Neuro-nutraceutical potential of Asparagus racemosus: A review

Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multifactorial pathophysiology. Their treatment strategies often only provide symptomatic relief, delaying disease progression without giving a complete cure. Potent and safer treatment alternatives beyond symptomatic relief are sought. Herbal supplements have surely been explored due to their multiple component nature to enhance the effect of western medications. One such well-documented nutraceutical in the ancient Greek, Chinese, and Ayurvedic medicine system known for its various medicinal benefits is Asparagus racemosus. Widely used for its lactogenic properties, A. racemosus is also cited in Ayurveda as a nervine tonic. A. racemosus based nutraceuticals have shown to possess adaptogenic, neuroprotective, antioxidant, anti-inflammatory, and nootropic activity under preclinical and clinical settings without posing significant adverse effects. A. racemosus extracts restore the perturbed neurotransmitters and prevent oxidative neuronal damage. From the available neuropharmacological researches, the physiological actions of A. racemosus can ultimately be directed for either augmentation of cognitive ability or in the management of neurological conditions such as stress, anxiety, depression, epilepsy, Parkinson's, and Alzheimer's disease. The studies focus on the multi-component extract, and the lack of standardization has been a major hurdle in preventing the allotment of reported neuropharmacological activity to one of the phytoconstituent. Herbal standardization of the plant extract based on a specific biomarker can help elucidate the intricate biomolecular pathway and neurocircuitries being involved. This, followed by rigorous standardized clinical trials, fixing dosages, and determining contraindications would facilitate the translation of A. racemosus to a FDA-approved neuromedicine for neurological disorders.

Novel Therapeutic Delivery of Nanocurcumin in Central Nervous System Related Disorders

Nutraceuticals represent complementary or alternative beneficial products to the expensive and high-tech therapeutic tools in modern medicine. Nowadays, their medical or health benefits in preventing or treating different types of diseases is widely accepted, due to fewer side effects than synthetic drugs, improved bioavailability and long half-life. Among herbal and natural compounds, curcumin is a very attractive herbal supplement considering its multipurpose properties. The potential effects of curcumin on glia cells and its therapeutic and protective properties in central nervous system (CNS)-related disorders is relevant. However, curcumin is unstable and easily degraded or metabolized into other forms posing limits to its clinical development. This is particularly important in brain pathologies determined blood brain barrier (BBB) obstacle. To enhance the stability and bioavailability of curcumin, many studies focused on the design and development of curcumin nanodelivery systems (nanoparticles, micelles, dendrimers, and diverse nanocarriers). These nanoconstructs can increase curcumin stability, solubility, in vivo uptake, bioactivity and safety. Recently, several studies have reported on a curcumin exosome-based delivery system, showing great therapeutical potential. The present work aims to review the current available data in improving bioactivity of curcumin in treatment or prevention of neurological disorders.

Obstacles against the Marketing of Curcumin as a Drug

Among the extensive public and scientific interest in the use of phytochemicals to prevent or treat human diseases in recent years, natural compounds have been highly investigated to elucidate their therapeutic effect on chronic human diseases including cancer, cardiovascular disease, and neurodegenerative disease. Curcumin, an active principle of the perennial herb Curcuma longa, has attracted an increasing research interest over the last half-century due to its diversity of molecular targets, including transcription factors, enzymes, protein kinases, growth factors, inflammatory cytokines, receptors, and it's interesting pharmacological activities. Despite that, the clinical effectiveness of the native curcumin is weak, owing to its low bioavailability and rapid metabolism. Preclinical data obtained from animal models and phase I clinical studies done in human volunteers confirmed a small amount of intestinal absorption, hepatic first pass effect, and some degree of intestinal metabolism, might explain its poor systemic availability when it is given via the oral route. During the last decade, researchers have attempted with new pharmaceutical methods such as nanoparticles, liposomes, micelles, solid dispersions, emulsions, and microspheres to improve the bioavailability of curcumin. As a result, a significant number of bioavailable curcumin-based formulations were introduced with a varying range of enhanced bioavailability. This manuscript critically reviews the available scientific evidence on the basic and clinical effects and molecular targets of curcumin. We also discuss its pharmacokinetic and problems for marketing curcumin as a drug.

Protective effects of maternal administration of curcumin and hesperidin in the rat offspring following repeated febrile seizure: Role of inflammation and TLR4

Neuroinflammation has a key role in seizure generation and perpetuation in the neonatal period, and toll-like receptor 4 (TLR4) pathway has a prominent role in neuroinflammatory diseases. Administration of antioxidants and targeting TLR4 in the embryonic period may protect rat offspring against the next incidence of febrile seizure and its harmful effects. Curcumin and hesperidin are natural compounds with anti-inflammatory and antioxidant properties and have an inhibitory action on TLR4 receptors. We evaluated the effect of maternal administration of curcumin and hesperidin on infantile febrile seizure and subsequent memory dysfunction in adulthood. Hyperthermia febrile seizure was induced on postnatal days 9-11 on male rat pups with 24 h intervals, in a Plexiglas box that was heated to ~45 °C by a heat lamp. We used enzyme-linked immunosorbent assay, Western blotting, malondialdehyde (MDA), and glutathione (GSH) assessment for evaluation of inflammatory cytokine levels, TLR4 protein expression, and oxidative responses in the hippocampal tissues. For assessing working memory and long-term potentiation, the double Y-maze test and Schaffer collateral-CA1 in vivo electrophysiological recording were performed, respectively Our results showed that curcumin and hesperidin decreased TNF-α, IL-10, and TLR4 protein expression and reversed memory dysfunction. However, they did not provoke a significant effect on GSH content or amplitude and slope of recorded fEPSPs in the hippocampus. In addition, curcumin, but not hesperidin, decreased interleukin-1β (IL-1β) and MDA levels. These findings imply that curcumin and hesperidin induced significant protective effects on febrile seizures, possibly via their anti-inflammatory and antioxidant properties and downregulation of TLR4.

Effect of curcumin on the inflammatory reaction and functional recovery after spinal cord injury in a hyperglycemic rat model

BACKGROUND CONTEXT

Curcumin has anti-inflammatory and antioxidant activities.

OBJECTIVE

This study aimed to investigate the effects of curcumin on the histological changes and functional recovery following spinal cord injury (SCI).

STUDY DESIGN

One hundred twenty-eight Sprague-Dawley rats were distributed into a sham, SCI only, SCI-hyperglycemia, and SCI-hyperglycemia-curcumin (200 mg/kg/day, i.p.) groups.

METHODS

SCI was induced using a clip at T9-10 and hyperglycemia was induced by streptozotocin (60-70 mg/kg, i.v.). Plasma malondialdehyde levels and superoxide dismutase activity was measured to determine oxidative stress. The activity of macrophages in the spinal cord after SCI was stained by the anti-CD68 antibody (ED-1). The tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 levels were measured by enzyme-linked immunosorbent assay and Western blot was used to verify the levels of mitogen-activated protein kinases and STAT3. The glial fibrillary acidic protein expression was evaluated by immunofluorescence analysis. Functional recovery was assessed according to the Basso, Beattie, and Bresnahan scale and histologic outcome was evaluated by the lesion volume and spared tissue area.

RESULTS

Superoxide dismutase activity increased, the malondialdehyde level decreased, and ED-1 macrophage marker level decreased in the SCI-hyperglycemia-curcumin group than in the SCI-hyperglycemia group at 2 weeks after SCI (p<.01). The SCI-hyperglycemia-curcumin group showed a statistically significant reduction in IL-6, IL-8, and TNF-α levels compared with the SCI-hyperglycemia group after SCI. The phosphorylated-extracellular signal-regulated kinase, phosphorylated-JNK, and phospho-p38 levels were significantly lower in the SCI-hypoglycemia-curcumin group than in the SCI-hypoglycemia group. The SCI-hyperglycemia-curcumin group showed a decrease in glial fibrillary acidic protein expression after SCI compared with the SCI-hyperglycemia group. The SCI-hyperglycemia-curcumin group showed a lower lesion volume, higher spared tissue, and better functional recovery than the SCI-hyperglycemia group.

CONCLUSIONS

Curcumin may have a potential neuroprotective effect in SCI with hyperglycemia.

CLINICAL SIGNIFICANCE

Curcumin decreased the inflammatory response and decreased astrogliosis and improved the functional recovery and histologic outcomes in SCI with hyperglycemia.

Curcumin, Hormesis and the Nervous System

Curcumin is a polyphenol compound extracted from the rhizome of Curcuma longa Linn (family Zingiberaceae) commonly used as a spice to color and flavor food. Several preclinical studies have suggested beneficial roles for curcumin as an adjuvant therapy in free radical-based diseases, mainly neurodegenerative disorders. Indeed, curcumin belongs to the family of hormetins and the enhancement of the cell stress response, mainly the heme oxygenase-1 system, is actually considered the common denominator for this dual response. However, evidence-based medicine has clearly demonstrated the lack of any therapeutic effect of curcumin to contrast the onset or progression of neurodegeneration and related diseases. Finally, the curcumin safety profile imposes a careful analysis of the risk/benefit balance prior to proposing chronic supplementation with curcumin.

The Effects of Curcumin on Serum Heat Shock Protein 27 Antibody Titers in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) is associated with an increased risk of cardiovascular disease and diabetes mellitus. Inflammation and oxidant stress are features of MetS that can enhance the expression and release of heat shock proteins (Hsps), including the small heat shock protein, Hsp 27, and that may subsequently lead to the production of Hsp27 antibodies (anti-Hsp 27). Curcumin is an anti-inflammatory and antioxidant phytochemical that may ameliorate these features of MetS. We investigated the effects of unformulated curcumin and phospholipidated curcumin on antibody titers to heat shock protein 27 (anti-Hsp 27) in patients with MetS. A randomized double-blind, placebo-controlled clinical trial design was used in 120 patients with MetS (diagnosed according to the International Diabetes Federation [IDF] criteria). Participants were randomly allocated to 3 groups, with 40 individuals per group, that received either 1 g/d curcumin, phospholipidated curcumin, or a placebo for 6 weeks. The changes in serum concentrations of anti-Hsp 27 did not differ significantly between study groups (p = .283). There was no significant difference between baseline and end-of-trial concentrations of anti-Hsp 27 in groups supplemented with curcumin (p = .177), phospholipidated curcumin (p = .798), or placebo (p = .663). Curcumin supplementation (1 g/d) has no significant effects on anti-Hsp 27 titers in patients with MetS.

Sesamol attenuates oxidative stress, apoptosis and inflammation in focal cerebral ischemia/reperfusion injury

The aim of the present study was to evaluate the therapeutic potential of sesamol treatment on focal ischemia/reperfusion (I/R) injury in the rat brain. The results demonstrated that pretreatment with sesamol seven days prior to focal cerebral I/R injury had significant positive effects, including improvements in neurological deficits (P<0.05), and a reduction in malondialdehyde content and elevation of antioxidant levels (superoxide dismutase, glutathione and glutatione peroxidase; both P<0.05). Furthermore, levels of B cell lymphoma-2 (Bcl-2)-associated X protein and caspase-3 were significantly downregulated, whereas the level of Bcl-2 was effectively increased. Conversely, the mRNA expression of proinflammatory cytokines were significantly reduced in focal cerebral I/R injury rats upon sesamol intervention. Therefore, the beneficial effects of sesamol on cerebral I/R injury may be due to the reduction of oxidative stress, inhibition of apoptosis and inflammation. The findings of the present study suggest that sesamol supplementation may serve as potent adjuvant in the treatment of focal cerebral ischemia/reperfusion injury due to its neuroprotective effects.

Protective Effects of Curcumin on Manganese-Induced BV-2 Microglial Cell Death

Curcumin, a bioactive component in tumeric, has been shown to exert antioxidant, anti-inflammatory, anticarcinogenic, hepatoprotective, and neuroprotective effects, but the effects of curcumin against manganese (Mn)-mediated neurotoxicity have not been studied. This study examined the protective effects of curcumin on Mn-induced cytotoxicity in BV-2 microglial cells. Curcumin (0.1-10 µM) dose-dependently prevented Mn (250 µM)-induced cell death. Mn-induced mitochondria-related apoptotic characteristics, such as caspase-3 and -9 activation, cytochrome c release, Bax increase, and Bcl-2 decrease, were significantly suppressed by curcumin. In addition, curcumin significantly increased intracellular glutathione (GSH) and moderately potentiated superoxide dismutase (SOD), both which were diminished by Mn treatment. Curcumin pretreatment effectively suppressed Mn-induced upregulation of malondialdehyde (MDA), total reactive oxygen species (ROS). Moreover, curcumin markedly inhibited the Mn-induced mitochondrial membrane potential (MMP) loss. Furthermore, curcumin was able to induce heme oxygenase (HO)-1 expression. Curcumin-mediated inhibition of ROS, down-regulation of caspases, restoration of MMP, and recovery of cell viability were partially reversed by HO-1 inhibitor (SnPP). These results suggest the first evidence that curcumin can prevent Mn-induced microglial cell death through the induction of HO-1 and regulation of oxidative stress, mitochondrial dysfunction, and apoptotic events.

MORIN MITIGATES OXIDATIVE STRESS, APOPTOSIS AND INFLAMMATION IN CEREBRAL ISCHEMIC RATS

Background:

Morin is a flavanoid which exhibits potent antioxidant activity in various oxidative stress related diseases. The current study was attempted to scrutinize the preclinical bio-efficacy of morin on focal ischemia.

Methods:

The animal model of focal cerebral ischemic injury was done by midbrain carotid artery occlusion (MCAO) method, followed by Morin (30mg/kg) administration for seven days.

Results:

The outcome of the study showed that treatment with morin displayed positive effects in reducing the focal cerebral ischemia. This effect was evident with the improvements in neurological deficits, reduction in MDA content and elevation of antioxidant levels (SOD, GSH and Gpx). Furthermore, protein expression of Bax and caspase-3 were effectively down-regulated, whilst the expression of Bcl-2 was significantly elevated. On the other hand, the mRNA expression of proinflammatory cytokines was significantly reduced in focal cerebral ischemic rats upon morin intervention.

Conclusion:

Thus, the beneficial effects of morin on cerebral ischemia assault may result from the reduction of oxidative stress, inhibition of apoptosis and inflammation. The neuroprotective effects of morin supplement may serve as potent adjuvant in the amelioration of ischemic stroke.

Dietary Phytochemicals in Neuroimmunoaging: A New Therapeutic Possibility for Humans?

Although several efforts have been made in the search for genetic and epigenetic patterns linked to diseases, a comprehensive explanation of the mechanisms underlying pathological phenotypic plasticity is still far from being clarified. Oxidative stress and inflammation are two of the major triggers of the epigenetic alterations occurring in chronic pathologies, such as neurodegenerative diseases. In fact, over the last decade, remarkable progress has been made to realize that chronic, low-grade inflammation is one of the major risk factor underlying brain aging. Accumulated data strongly suggest that phytochemicals from fruits, vegetables, herbs, and spices may exert relevant immunomodulatory and/or anti-inflammatory activities in the context of brain aging. Starting by the evidence that a common denominator of aging and chronic degenerative diseases is represented by inflammation, and that several dietary phytochemicals are able to potentially interfere with and regulate the normal function of cells, in particular neuronal components, aim of this review is to summarize recent studies on neuroinflammaging processes and proofs indicating that specific phytochemicals may act as positive modulators of neuroinflammatory events. In addition, critical pathways involved in mediating phytochemicals effects on neuroinflammaging were discussed, exploring the real impact of these compounds in preserving brain health before the onset of symptoms leading to inflammatory neurodegeneration and cognitive decline.

Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R

BACKGROUND

Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear.

OBJECTIVE

To investigate the effects of curcumin on cerebral I/R injury associated with water content, infarction volume, and the expression of nuclear factor-kappa-B (NF-κB) and nuclear factor-erythroid-related factor-2 (Nrf2).

METHODS

Middle cerebral artery occlusion (MCAO, 1-hour occlusion and 24-hour reperfusion) was performed in male Wistar rats (n=64) as a cerebral I/R injury model. In the MCAO+CUR group, the rats were administered curcumin (300mg/kg BW, i.p.) at 30min after occlusion. The same surgical procedures were performed in SHAM rats without MCAO occlusion. At 24h post-operation, the parameters, including neurological deficit scores, blood brain barrier (BBB) disruption, water content, and infarction volume, were determined. Brain tissue NF-κB and Nrf2 expression levels were assayed through immunohistochemistry.

RESULTS

Compared with the SHAM group, BBB disruption, neurological deficit, and increased brain water content and infarction volume were markedly demonstrated in the MCAO group. NF-κB expression was enhanced in the MCAO group. However, in the MCAO+CUR group, the upregulation of Nrf2, an anti-oxidation related protein, was consistent with a significant decline in the water content, infarction volume, and NF-κB expression.

CONCLUSION

The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB.

Curcumin inhibits superoxide anion-induced pain-like behavior and leukocyte recruitment by increasing Nrf2 expression and reducing NF-κB activation

OBJECTIVE

This study aimed at evaluating the activity of curcumin in superoxide anion-induced pain-like behavior and leukocyte recruitment in mice.

TREATMENT

Administration of curcumin 10 mg/kg subcutaneously 1 h before stimulus.

METHODS

KO2 was used as superoxide anion donor. Overt pain-like behaviors were determined by the number of abdominal writhings, paw flinches and time spent licking the paw. Mechanical and thermal hyperalgesia were determined using an electronic anesthesiometer and hot plate, respectively. Cytokine concentration and NF-κB activity were determined by ELISA, antioxidant effect by nitrobluetretrazolium assay and ABTS radical scavenging ability. Myeloperoxidase activity was measured by colorimetric assay. The Nrf2, heme oxygenase-1 (HO-1) and gp91phox mRNA expression was determined by quantitative PCR. Data were analyzed by ANOVA followed by Tukey's post hoc and considered significant when p<0.05.

RESULTS

Curcumin inhibited superoxide anion-induced overt pain-like behaviors as well as mechanical and thermal hyperalgesia. Curcumin also inhibited superoxide anion-induced leukocyte recruitment in the peritoneal cavity and in the paw skin inhibited myeloperoxidase activity, oxidative stress, IL-1β and TNF-α production and NF-κB activation as well as enhanced IL-10 production, and HO-1 and Nrf2 mRNA expression.

CONCLUSION

Curcumin inhibits superoxide anion-induced inflammatory pain-like behaviors and leukocyte recruitment by targeting inflammatory molecules and oxidative stress; and inducing antioxidant and anti-inflammatory pathways.

Curcumin as a double-edged sword for stem cells: dose, time and cell type-specific responses to curcumin

Background

The beneficial effects of curcumin which includes its antioxidant, anti-inflammatory and cancer chemo-preventive properties have been identified. Little information is available regarding the optimal dose and treatment periods of curcumin on the proliferation rate of different sources of stem cells.

Methods

In this study, the effect of various concentrations of curcumin on the survival and proliferation of two types of outstanding stem cells which includes bone marrow stem cells (BMSCs) and adult rat neural stem/progenitor cells (NS/PCs) at different time points was investigated. BMSCs were isolated from bilateral femora and tibias of adult Wistar rats. NS/PCs were obtained from subventricular zone of adult Wistar rat brain. The curcumin (0.1, 0.5, 1, 5 and 10 μM/L) was added into a culture medium for 48 or 72 h. Fluorescent density of 5-bromo-2′-deoxyuridine (Brdu)-positive cells was considered as proliferation index. In addition, cell viability was assessed by MTT assay.

Results

Treatment of BMSCs with curcumin after 48 h, increased cell survival and proliferation in a dose-dependent manner. However, it had no effect on NSCs proliferation except a toxic effect in the concentration of 10 μM of curcumin. After a 72 h treatment period, BMSCs and NS/PCs survived and proliferated with low doses of curcumin. However, high doses of curcumin administered for 72 h showed toxic effects on both stem cells.

Conclusions

These findings suggest that curcumin survival and proliferative effects depend on its concentration, treatment period and the type of stem cells. Appropriate application of these results may be helpful in the outcome of combination therapy of stem cells and curcumin.

Molecular chaperone dysfunction in neurodegenerative diseases and effects of curcumin

The intra- and extracellular accumulation of misfolded and aggregated amyloid proteins is a common feature in several neurodegenerative diseases, which is thought to play a major role in disease severity and progression. The principal machineries maintaining proteostasis are the ubiquitin proteasomal and lysosomal autophagy systems, where heat shock proteins play a crucial role. Many protein aggregates are degraded by the lysosomes, depending on aggregate size, peptide sequence, and degree of misfolding, while others are selectively tagged for removal by heat shock proteins and degraded by either the proteasome or phagosomes. These systems are compromised in different neurodegenerative diseases. Therefore, developing novel targets and classes of therapeutic drugs, which can reduce aggregates and maintain proteostasis in the brains of neurodegenerative models, is vital. Natural products that can modulate heat shock proteins/proteosomal pathway are considered promising for treating neurodegenerative diseases. Here we discuss the current knowledge on the role of HSPs in protein misfolding diseases and knowledge gained from animal models of Alzheimer's disease, tauopathies, and Huntington's diseases. Further, we discuss the emerging treatment regimens for these diseases using natural products, like curcumin, which can augment expression or function of heat shock proteins in the cell.

Advances in Herbal Medicine for Treatment of Ischemic Brain Injury

Ischemic brain injury is one of the leading causes of death worldwide and has attracted a lot of attention in the field of drug discovery. Cerebral ischemia is a complex pathological process involving a series of mechanisms, including generation of free radicals, oxidative stress, disruption of the membrane function, release of neurotransmitters and apoptosis. Thrombolytic therapy is the most effective therapeutic strategy, but the benefits are far from being absolute. Increased attention in the field of drug discovery has been focused on using natural compounds from traditional medicinal herbs for neuroprotection, which appears to be a promising therapeutic option for cerebral ischemia with minimal systemic adverse effects that could limit their long term use. The scenario calls for extensive investigations which can result in the development of lead molecules for neuroprotection in the future. In this context, the present review focuses on possible mechanisms underlying the beneficial effects of herbal drugs in patients with cerebral ischemic injury. Natural compounds have been demonstrated to have neurofunctional regulatory actions with antioxidative, anti-inflammatory, calcium antagonizing and anti-apoptotic activities. Among the several leads obtained from plant sources as potential neuroprotective agents, resveratrol, EGb761, curcumin and epigallocatechin-3-gallate have shown significant therapeutic benefits in cerebral ischemic conditions. However, ligustilide, tanshinone, scutellarin and shikonin are the few lead molecules which are under investigation for treatment of cerebral ischemia.

The neuroprotective effect of treatment with curcumin in acute spinal cord injury: laboratory investigation

The purpose of this study was investigating the effects of curcumin on the histological changes and functional recovery following spinal cord injury (SCI) in a rat model. Following either sham operation or SCI, 36 male Sprague–Dawley rats were distributed into three groups: sham group, curcumin-treated group, and vehicle-injected group. Locomotor function was assessed according to the Basso, Beattie, and Bresnahan (BBB) scale in rats who had received daily intraperitoneal injections of 200 mg/kg curcumin or an equivalent volume of vehicle for 7 days following SCI. The injured spinal cord was then examined histologically, including quantification of cavitation. BBB scores were significantly higher in rats receiving curcumin than receiving vehicle (P < 0.05). The cavity volume was significantly reduced in the curcumin group as compared to the control group (P = 0.039). Superoxide dismutase (SOD) activity was significantly elevated in the curcumin group as compared to the vehicle group but was not significantly different from the sham group (P < 0.05, P > 0.05, respectively) at one and two weeks after SCI. Malondialdehyde (MDA) levels were significantly elevated in the vehicle group as compared to the sham group (P < 0.05 at 1 and 2 weeks). MDA activity was significantly reduced in the curcumin group at 2 weeks after SCI when compared to the vehicle group (P = 0.004). The numbers of macrophage were significantly decreased in the curcumin group (P = 0.001). This study demonstrated that curcumin enhances early functional recovery after SCI by diminishing cavitation volume, anti-inflammatory reactions, and antioxidant activity.

Therapeutic effects of traditional herbal medicine on cerebral ischemia: a perspective of vascular protection

Although many agents for acute ischemic stroke treatment have been developed from extensive preclinical studies, most have failed in clinical trials. As a result, researchers are seeking other methods or agents based on previous studies. Among the various prospective approaches, vascular protection might be the key for development of therapeutic agents for stroke and for improvements in the efficacy and safety of conventional therapies. Traditional medicines in Asian countries are based on clinical experiences and literature accumulated over thousands of years. To date, many studies have used traditional herbal medicines to prove or develop new agents based on stroke treatments mentioned in traditional medicinal theory or other clinical data. In the current review, we describe the vascular factors related to ischemic brain damage and the herbal medicines that impact these factors, including Salviae Miltiorrhizae Radix, Notoginseng Radix, and Curcumae Rhizoma, based on scientific reports and traditional medical theory. Further, we point out the problems associated with herbal medicines in stroke research and propose better methodologies to address these problems.

Curcumin nanoparticles attenuate neurochemical and neurobehavioral deficits in experimental model of Huntington's disease

Till date, an exact causative pathway responsible for neurodegeneration in Huntington's disease (HD) remains elusive; however, mitochondrial dysfunction appears to play an important role in HD pathogenesis. Therefore, strategies to attenuate mitochondrial impairments could provide a potential therapeutic intervention. In the present study, we used curcumin encapsulated solid lipid nanoparticles (C-SLNs) to ameliorate 3-nitropropionic acid (3-NP)-induced HD in rats. Results of MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay and succinate dehydrogenase (SDH) staining of striatum revealed a marked decrease in Complex II activity. However, C-SLN-treated animals showed significant increase in the activity of mitochondrial complexes and cytochrome levels. C-SLNs also restored the glutathione levels and superoxide dismutase activity. Moreover, significant reduction in mitochondrial swelling, lipid peroxidation, protein carbonyls and reactive oxygen species was observed in rats treated with C-SLNs. Quantitative PCR and Western blot results revealed the activation of nuclear factor-erythroid 2 antioxidant pathway after C-SLNs administration in 3-NP-treated animals. In addition, C-SLN-treated rats showed significant improvement in neuromotor coordination when compared with 3-NP-treated rats. Thus, the results of this study suggest that C-SLNs administration might be a promising therapeutic intervention to ameliorate mitochondrial dysfunctions in HD.

Neuroprotective effects of chloroform and petroleum ether extracts of Nigella sativa seeds in stroke model of rat

PURPOSE:

Stroke still remains a challenge for the researchers and scientists for developing ideal drug. Several new drugs are being evaluated showing excellent results in preclinical studies but when tested in clinical trials, they failed. Many herbal drugs in different indigenous system of medicine claim to have beneficial effects but not extensively evaluated for stroke (cerebral ischemia).

AIM:

The present study was undertaken to evaluate chloroform and petroleum ether extract of Nigella sativa seeds administered at a dose of 400 mg/kg, per orally for seven days in middle cerebral artery occluded (MCAO) rats for its neuroprotective role in cerebral ischemia.

MATERIALS AND METHODS:

Focal cerebral ischemia was induced by middle cerebral artery occlusion for two hours followed by reperfusion for 22 hours. After 24 hours, grip strength, locomotor activity tests were performed in different treatment groups of rats. After completing behavioral tests, animals were sacrificed; brains were removed for the measurement of infarct volume followed by the estimation of markers of oxidative stress.

RESULTS:

Both chloroform and petroleum ether extracts-pretreated rats showed improvement in locomotor activity and grip strength, reduced infarct volume when compared with MCAO rats. MCA occlusion resulted in the elevation of levels of thiobarbituric acid reactive substance (TBARS), while a reduction in the levels of glutathione (GSH) and antioxidant enzymes viz. superoxide dismutase (SOD) and catalase levels were observed. Pre-treatment of both extracts of Nigella sativa showed reduction in TBARS, elevation in glutathione, SOD, and catalase levels when compared with MCAO rats.

CONCLUSION:

The chloroform and petroleum ether extract of Nigella sativa showed the protective effects in cerebral ischemia. The present study confirms the antioxidant, free radical scavenging, and anti-inflammatory properties of Nigella sativa already reported.

Lycopene inhibits ischemia/reperfusion-induced neuronal apoptosis in gerbil hippocampal tissue

Plant lycopene exhibits antioxidant activity in animal tissues. Transient cerebral ischemia/reperfusion in Mongolian gerbils resulted in delayed neuronal death in hippocampal regions. We examined the antioxidant effects of lycopene because we expected lycopene to attenuate ischemia-related neuronal damage by controlling apoptosis at the gene level. The gerbils were divided into two groups: the normal feeding (control) group that received normal market food (MF) and the lycopene group that received MF containing lycopene (5 mg in 100 g MF food). After 1.5-2.0 months (when body weight were 60-65 g), the lycopene level was 38.2 ± 17.6 ng/ml in serum and 11.9 ± 4.0 μg/g-wet weight tissue in the liver. Levels of B cell leukemia-2, an apoptosis-suppressing protein, decreased in control animal brains 1, 3, and 7 days after surgery, whereas the levels increased in lycopene-treated animal brains. Moreover, cysteinyl aspartate-specific protease-3 activity increased gradually after ischemia, but was suppressed in the lycopene-treated animal brains 7 days after surgery. Finally, hippocampal superoxide dismutase (SOD) activity decreased in the control group 3 h after ischemia and, gradually increased thereafter, whereas it was significantly elevated in the lycopene group. Thus, orally administered lycopene is accumulated in the body, and provided protections against ischemia/reperfusion-induced brain injury by inducing an increase in SOD activity and inhibiting apoptosis.

RETRACTED: Curcumin restores Nrf2 levels and prevents quinolinic acid-induced neurotoxicity

Neurological diseases comprise a group of heterogeneous disorders characterized by progressive brain dysfunction and cell death. In the next years, these diseases are expected to constitute a world-wide health problem. Because excitotoxicity and oxidative stress are involved in neurodegenerative diseases, it becomes relevant to describe pharmacological therapies designed to activate endogenous cytoprotective systems. Activation of transcription factor Nrf2 stimulates cytoprotective vitagenes involved in antioxidant defense. In this work, we investigated the ability of the antioxidant curcumin to induce transcription factor Nrf2 in a neurodegenerative model induced by quinolinic acid in rats. Animals were administered with curcumin (400 mg/kg, p.o.) for 10 days, and then intrastriatally infused with quinolinic acid (240 nmol) on day 10 of treatment. Curcumin prevented rotation behavior (6 days post-lesion), striatal morphological alterations (7 days post-lesion) and neurodegeneration (1 and 3 days post-lesion) induced by quinolinic acid. Curcumin also reduced quinolinic acid-induced oxidative stress (measured as protein carbonyl content) at 6 h post-lesion. The protective effects of curcumin were associated to its ability to prevent the quinolinic acid-induced decrease of striatal intra-nuclear Nrf2 levels (30 and 120 min post-lesion), and total superoxide dismutase and glutathione peroxidase activities (1 day post-lesion). Therefore, results of this study support the concept that neuroprotection induced by curcumin is associated with its ability to activate the Nrf2 cytoprotective pathway and to increase the total superoxide dismutase and glutathione peroxidase activities.

Improvement of neuropathology and transcriptional deficits in CAG 140 knock-in mice supports a beneficial effect of dietary curcumin in Huntington's disease

Backgound

No disease modifying treatment currently exists for Huntington's disease (HD), a fatal neurodegenerative disorder characterized by the formation of amyloid-like aggregates of the mutated huntingtin protein. Curcumin is a naturally occurring polyphenolic compound with Congo red-like amyloid binding properties and the ability to cross the blood brain barrier. CAG140 mice, a knock-in (KI) mouse model of HD, display abnormal aggregates of mutant huntingtin and striatal transcriptional deficits, as well as early motor, cognitive and affective abnormalities, many months prior to exhibiting spontaneous gait deficits, decreased striatal volume, and neuronal loss. We have examined the ability of life-long dietary curcumin to improve the early pathological phenotype of CAG140 mice.

Results

KI mice fed a curcumin-containing diet since conception showed decreased huntingtin aggregates and increased striatal DARPP-32 and D1 receptor mRNAs, as well as an amelioration of rearing deficits. However, similar to other antioxidants, curcumin impaired rotarod behavior in both WT and KI mice and climbing in WT mice. These behavioral effects were also noted in WT C57Bl/6 J mice exposed to the same curcumin regime as adults. However, neither locomotor function, behavioral despair, muscle strength or food utilization were affected by curcumin in this latter study. The clinical significance of curcumin's impairment of motor performance in mice remains unclear because curcumin has an excellent blood chemistry and adverse event safety profile, even in the elderly and in patients with Alzheimer's disease.

Conclusion

Together with this clinical experience, the improvement in several transgene-dependent parameters by curcumin in our study supports a net beneficial effect of dietary curcumin in HD.

Ferulic acid ethyl ester as a potential therapy in neurodegenerative disorders

Oxidative stress is involved in the onset, progression and pathogenesis of a number of diseases including neurodegenerative diseases. It is critical to develop a pharmacological approach to combat oxidative stress which may reduce the risk of diseases and help in promoting healthy life. In an attempt to reduce the side effects associated with allopathic medicines a number of studies are now focusing on developing treatment regimens from naturally occurring plant products. In this review, the protective role of ferulic acid (4-hydroxy-3-methoxycinnamic acid) (FA), a naturally occurring antioxidant compound found in fruit, some vegetables, and grains, and its ethyl ester derivative are discussed with respect to neurodegeneration. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Curcumin sensitizes chemotherapeutic drugs via modulation of PKC, telomerase, NF-κB and HDAC in breast cancer

Background: Several tumor markers are overexpressed in breast cancer. Chemotherapy in breast cancer fails due to resistance to chemotherapeutic drugs. A phytochemical such as curcumin can be used in a therapeutic modality as it elicits anti-tumor effects. Methods: Action of curcumin on the expression of several tumor markers, such as protein kinase C, telomerase, NF-κB and histone deacetylase in MCF-7 (ER positive), MDA-MB-231 (ER negative), MCF-12F (control) and also in mice mammary tumors were investigated. Results: Curcumin downregulated the expression of tumor markers both in vitro and in vivo and sensitized tumor cells to the chemotherapeutic drugs cyclophosphamide and paclitaxel. Discussion: Curcumin may be of considerable value in synergistic therapy of cancer such that the drug dose level could be minimized reducing the associated toxicity.

Comparison of phosphorylated extracellular signal-regulated kinase 1/2 immunoreactivity in the hippocampal Ca1 region induced by transient cerebral ischemia between adult and aged gerbils

In this study, the authors examined the difference of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in the hippocampal CA1 region (CA1) between adult and aged gerbils after 5 min of transient cerebral ischemia. Delayed neuronal death in the CA1 of the aged group was much slower than that in the adult group after ischemia/reperfusion (I/R). pERK1/2 immunoreaction was observed in the CA1 region of the sham-operated adult gerbil. pERK1/2 immunoreactivity and protein levels in the ischemic CA1 region of the adult group were markedly increased 4 days after I/R, and then reduced up to 10 days after I/R. In contrast, pERK1/2 immunoreaction was hardly detected in the CA1 region of sham-operated aged gerbils, and the immunoreactivity increased from 1 day after the ischemic insult, and still observed until 10 days post-ischemia. In addition, pERK1/2-immunoreaction was expressed in astrocytes in the ischemic CA1 region: The expression in the ischemia-operated aged gerbils was later than that in the ischemia-operated adult gerbils. These results indicate that different patterns of ERK1/2 immunoreactivity may be associated with different processes of delayed neuronal death in adult and aged animals.

Enhanced glutathione efflux from astrocytes in culture by low extracellular Ca2+ and curcumin

Efflux of glutathione (GSH) from astrocytes has been suggested as a key factor for neuroprotection by astrocytes. Here we evaluated if the Nrf2 activator curcumin affects basal and stimulated (Ca(2+) omission) GSH efflux from cultures of astroglial cells. Stimulated efflux of GSH was observed at medium concentration of 0, 0.1 mM Ca(2+), but not at 0.2 or 0.3 mM Ca(2+). Astroglia treated with 30 microM curcumin increased the cellular content of GSH in parallel with elevated basal and stimulated efflux. Conversely treatment with buthionine sulfoximine lowered efflux of GSH. The efflux stimulated by Ca(2+)- omission was not affected by the P2X7-receptor antagonist Blue Brilliant G (100 nM) or the pannexin mimetic/blocking peptide (10)Panx1 but inhibited by the gap junction blocker carbenoxolone (100 microM) and a hemichannel blocker Gap26 (300 microM). RNAi directed against Nrf2 partly inhibited the effect of curcumin. The results show that elevated cellular GSH by curcumin treatment enhance efflux from astroglial cells, a process which appear to be a prerequisite for astroglial mediated neuroprotection.

Curcumin upregulates transcription factor Nrf2, HO-1 expression and protects rat brains against focal ischemia

BACKGROUND

Oxidative and cytotoxic damage plays an important role in cerebral ischemic pathogenesis and may represent a target for treatment. Curcumin is proved to elicit a vanity of biological effects through its antioxidant and anti-inflammatory properties. But the mechanisms underlying are poorly understood. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) coordinates expression of genes required for free radical scavenging, detoxification of xenobiotics, and maintenance of redox potential. This study evaluated the time course expression regularity of Nrf2, HO-1 and the curcumin's role in cerebral ischemia and its potential mechanism.

METHODS

Male, Sprague-Dawley rats were subjected to permanent focal cerebral ischemia by right MCA occlusion. Experiment 1 was used to evaluate the expression of Nrf2 and HO-1 in the cerebral ischemia, 6 time points was included. Experiment 2 was used to detect curcumin's neuroprotection in cerebral ischemia. At 24 h neurological deficit was evaluated using a modified six point scale; brain water content was measured; infarct size was analysed with 2, 3, 5-triphenyltetrazolium chloride (TTC). Immunohistochemistry, RT-PCR, Western blot, and confocal microscope were used to analyse the expression of Nrf2 and HO-1.

RESULTS

Compared with sham-operated, Nrf2 and HO-1 were upregulated at gene and protein level in ischemic brain, beginning at 3 h and peaking at 24 h after MCAO (P<0.05). Curcumin high dose (100 mg/kg) upregulated Nrf2 and HO-1 in MCAO-affected brain tissue and reduced infarct volume (P<0.05), brain water content (P<0.05) and behavioral deficits (P<0.05) caused by MCAO.

CONCLUSIONS

Nrf2 and HO-1 were induced at the early stage after MCAO. Curcumin protected the brain from damage caused by MCAO, this effect may be through upregulation of the transcription factor Nrf2 expression. Nrf2 may be one of the strategic targets for cerebral ischemic therapies.

Curcumin and the cellular stress response in free radical-related diseases

Free radicals play a main pathogenic role in several human diseases such as neurodegenerative disorders, diabetes, and cancer. Although there has been progress in treatment of these diseases, the development of important side effects may complicate the therapeutic course. Curcumin, a well known spice commonly used in India to make foods colored and flavored, is also used in traditional medicine to treat mild or moderate human diseases. In the recent years, a growing body of literature has unraveled the antioxidant, anticarcinogenic, and antinfectious activity of curcumin based on the ability of this compound to regulate a number of cellular signal transduction pathways. These promising data obtained in vitro are now being translated to the clinic and more than ten clinical trials are currently ongoing worldwide. This review outlines the biological activities of curcumin and discusses its potential use in the prevention and treatment of human diseases.

Oxidative stress and hippocampus in a low-grade hepatic encephalopathy model: protective effects of curcumin

AIM

The present study was performed on prehepatic portal hypertensive rats, a model of low-grade hepatic encephalopathy, designed to evaluate whether oxidative stress was a possible pathway implicated in hippocampal damage and if so, the effect of an anti-oxidant to prevent it.

METHODS

Prehepatic portal hypertension was induced by a regulated portal vein stricture. Oxidative stress was investigated by assessing related biochemical parameters in rat hippocampus. The effect of the anti-oxidant curcumin, administered in a single i.p. dose of 100 mg/kg on the seventh, ninth and eleventh days after surgery, was evaluated.

RESULTS

Oxidative stress in the rat hippocampal area was documented. Curcumin significantly decreased tissue malondialdehyde levels and significantly increased glutathione peroxidase, catalase and superoxide dismutase activities in the hippocampal tissue of portal hypertensive rats.

CONCLUSION

Oxidative stress was found to be implicated in the hippocampal damage and curcumin protected against this oxidative stress in low-grade hepatic encephalopathic rats. These protective effects may be attributed to its anti-oxidant properties.

Cellular stress response: a novel target for chemoprevention and nutritional neuroprotection in aging, neurodegenerative disorders and longevity

The predominant molecular symptom of aging is the accumulation of altered gene products. Moreover, several conditions including protein, lipid or glucose oxidation disrupt redox homeostasis and lead to accumulation of unfolded or misfolded proteins in the aging brain. Alzheimer's and Parkinson's diseases or Friedreich ataxia are neurological diseases sharing, as a common denominator, production of abnormal proteins, mitochondrial dysfunction and oxidative stress, which contribute to the pathogenesis of these so called "protein conformational diseases". The central nervous system has evolved the conserved mechanism of unfolded protein response to cope with the accumulation of misfolded proteins. As one of the main intracellular redox systems involved in neuroprotection, the vitagene system is emerging as a neurohormetic potential target for novel cytoprotective interventions. Vitagenes encode for cytoprotective heat shock proteins (Hsp) Hsp70 and heme oxygenase-1, as well as thioredoxin reductase and sirtuins. Nutritional studies show that ageing in animals can be significantly influenced by dietary restriction. Thus, the impact of dietary factors on health and longevity is an increasingly appreciated area of research. Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease. Genetics has revealed that ageing may be controlled by changes in intracellular NAD/NADH ratio regulating sirtuin, a group of proteins linked to aging, metabolism and stress tolerance in several organisms. Recent findings suggest that several phytochemicals exhibit biphasic dose responses on cells with low doses activating signaling pathways that result in increased expression of vitagenes encoding survival proteins, as in the case of the Keap1/Nrf2/ARE pathway activated by curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Consistently, the neuroprotective roles of dietary antioxidants including curcumin, acetyl-L-carnitine and carnosine have been demonstrated through the activation of these redox-sensitive intracellular pathways. Although the notion that stress proteins are neuroprotective is broadly accepted, still much work needs to be done in order to associate neuroprotection with specific pattern of stress responses. In this review the importance of vitagenes in the cellular stress response and the potential use of dietary antioxidants in the prevention and treatment of neurodegenerative disorders is discussed.

Potential therapeutic effects of curcumin, the anti-inflammatory agent, against neurodegenerative, cardiovascular, pulmonary, metabolic, autoimmune and neoplastic diseases

Although safe in most cases, ancient treatments are ignored because neither their active component nor their molecular targets are well defined. This is not the case, however, with curcumin, a yellow-pigment substance and component of turmeric (Curcuma longa), which was identified more than a century ago. For centuries it has been known that turmeric exhibits anti-inflammatory activity, but extensive research performed within the past two decades has shown that this activity of turmeric is due to curcumin (diferuloylmethane). This agent has been shown to regulate numerous transcription factors, cytokines, protein kinases, adhesion molecules, redox status and enzymes that have been linked to inflammation. The process of inflammation has been shown to play a major role in most chronic illnesses, including neurodegenerative, cardiovascular, pulmonary, metabolic, autoimmune and neoplastic diseases. In the current review, we provide evidence for the potential role of curcumin in the prevention and treatment of various proinflammatory chronic diseases. These features, combined with the pharmacological safety and negligible cost, render curcumin an attractive agent to explore further.

Curcumin stimulates proliferation of embryonic neural progenitor cells and neurogenesis in the adult hippocampus

Curcumin is a natural phenolic component of yellow curry spice, which is used in some cultures for the treatment of diseases associated with oxidative stress and inflammation. Curcumin has been reported to be capable of preventing the death of neurons in animal models of neurodegenerative disorders, but its possible effects on developmental and adult neuroplasticity are unknown. In the present study, we investigated the effects of curcumin on mouse multi-potent neural progenitor cells (NPC) and adult hippocampal neurogenesis. Curcumin exerted biphasic effects on cultured NPC; low concentrations stimulated cell proliferation, whereas high concentrations were cytotoxic. Curcumin activated extracellular signal-regulated kinases (ERKs) and p38 kinases, cellular signal transduction pathways known to be involved in the regulation of neuronal plasticity and stress responses. Inhibitors of ERKs and p38 kinases effectively blocked the mitogenic effect of curcumin in NPC. Administration of curcumin to adult mice resulted in a significant increase in the number of newly generated cells in the dentate gyrus of hippocampus, indicating that curcumin enhances adult hippocampal neurogenesis. Our findings suggest that curcumin can stimulate developmental and adult hippocampal neurogenesis, and a biological activity that may enhance neural plasticity and repair.

Omega-3 fatty acids and antioxidants in neurological and psychiatric diseases: an overview

RATIONALE

Omega-3 fatty acids are known to play a role in nervous system activity, cognitive development, memory-related learning, neuroplasticity of nerve membranes, synaptogenesis and synaptic transmission. The brain is considered abnormally sensitive to oxidative damage, and aging is considered one of the most significant risk factors for degenerative neurological disorders. Recently, clinical trials of several neurodegenerative diseases have increasingly targeted the evaluation of the effectiveness of various antioxidants.

OBJECTIVES

The effects of omega-3 fatty acids and antioxidants on the anatomic and functional central nervous system development and their possible therapeutical use in some neurological and psychiatric pathologies are evaluated.

RESULTS

A number of critical trials have confirmed the benefits of dietary supplementation with omega-3 fatty acids not only in several psychiatric conditions, but also in inflammatory and autoimmune and neurodegenerative diseases. Many evidences indicate that antioxidants are also essential in maintaining a correct neurophysiology.

CONCLUSIONS

Omega-3 fatty acids could be useful in the prevention of different pathologies, such as cardiovascular, psychiatric, neurological, dermatological and rheumatological disorders. A number of studies suggest that antioxidants can prevent the oxidation of various macromolecules such as DNA, proteins, and lipids. The ideal use of antioxidants should be a prophylactic and continue treatment before aging.