Botanical phenolics and brain health

Plants-Derived Neuroprotective Agents: Cutting the Cycle of Cell Death through Multiple Mechanisms

Neuroprotection is the preservation of the structure and function of neurons from insults arising from cellular injuries induced by a variety of agents or neurodegenerative diseases (NDs). The various NDs including Alzheimer's, Parkinson's, and Huntington's diseases as well as amyotropic lateral sclerosis affect millions of people around the world with the main risk factor being advancing age. Each of these diseases affects specific neurons and/or regions in the brain and involves characteristic pathological and molecular features. Hence, several in vitro and in vivo study models specific to each disease have been employed to study NDs with the aim of understanding their underlying mechanisms and identifying new therapeutic strategies. Of the most prevalent drug development efforts employed in the past few decades, mechanisms implicated in the accumulation of protein-based deposits, oxidative stress, neuroinflammation, and certain neurotransmitter deficits such as acetylcholine and dopamine have been scrutinized in great detail. In this review, we presented classical examples of plant-derived neuroprotective agents by highlighting their structural class and specific mechanisms of action. Many of these natural products that have shown therapeutic efficacies appear to be working through the above-mentioned key multiple mechanisms of action.

Lifestyle Modulators of Neuroplasticity: How Physical Activity, Mental Engagement, and Diet Promote Cognitive Health during Aging

The number of the elderly across the globe will approximate 2.1 billion by 2050. Juxtaposed against this burgeoning segment of the population is evidence that nonpathological aging is associated with an increased risk for cognitive decline in a variety of domains, changes that can cause mild disability even before the onset of dementia. Given that pharmacological treatments that mitigate dementia are still outstanding, alternative therapeutic options are being investigated increasingly. The results from translational studies have shown that modifiable lifestyle factors-including physical activity, cognitive engagement, and diet-are a key strategy for maintaining brain health during aging. Indeed, a multiplicity of studies has demonstrated relationships between lifestyle factors, brain structure and function, and cognitive function in aging adults. For example, physical activity and diet modulate common neuroplasticity substrates (neurotrophic signaling, neurogenesis, inflammation, stress response, and antioxidant defense) in the brain whereas cognitive engagement enhances brain and cognitive reserve. The aims of this review are to evaluate the relationship between modifiable lifestyle factors, neuroplasticity, and optimal brain health during aging; to identify putative mechanisms that contribute positive brain aging; and to highlight future directions for scientists and clinicians. Undoubtedly, the translation of cutting-edge knowledge derived from the field of cognitive neuroscience will advance our understanding and enhance clinical treatment interventions as we endeavor to promote brain health during aging.

The mechanism of neuroprotective action of natural compounds

Disturbance of cerebral redox homeostasis is the primary cause of human neurodegenerative disorders, such as Parkinson's disease or Alzheimer's disease. Well known experimental research demonstrates that oxidative stress is a main cause of cell death. A high concentration of reactive oxygen and nitrogen species leads to damage of a lot of proteins, lipids and also DNA. Synthetic compounds used for the treatment in the neurodegenerative diseases failed to meet the hopes they had raised and often exhibit a number of side effects. Therefore, in recent years interest in natural compounds derived from plants appears to be on the rise. This review describes a few natural compounds (1MeTIQ, resveratrol, curcumin, vitamin C and Gingko biloba) which revealed neuroprotective potential both in experimental studies and clinical trials. 1MeTIQ has a privileged position because, as opposed to the remaining compounds, it is an endogenous amine synthesized in human and animal brain. Based on evidence from research, it seems that a common protective mechanism for all the above-mentioned natural compounds relies on their ability to inhibit or even scavenge the excess of free radicals generated in oxidative and neurotoxin-induced processes in nerve cells of the brain. However, it was demonstrated that further different molecular processes connected with neurotoxicity (e.g. the inhibition of mitochondrial complex I, activation of caspase-3, apoptosis) follow later and are initiated by the reactive oxygen species. What is more, these natural compounds are able to inhibit further stages of apoptosis triggered by neurotoxins in the brain.

Increased intestinal permeation and modulation of presystemic metabolism of resveratrol formulated into self-emulsifying drug delivery systems

Despite various beneficial biological properties, resveratrol lacks therapeutic applications because of poor bioavailability due to variable absorption and extensive metabolism. The present study aims at evaluating the capability of self-emulsifying drug delivery systems (SEDDS) to enhance resveratrol permeation across rat intestine and to modulate its presystemic metabolism. For that purpose, semi-solid (SS) and liquid (L) SEDDS were prepared and dispersed in an aqueous buffer to produce nanoemulsions (NE). The jejunal absorptive transepithelial fluxes (J_ms) of resveratrol elicited by these formulations (SS-NE and L-NE) and presystemic metabolization were determined on Ussing chambers. The absorptive fluxes through the intestinal epithelium from the nanoemulsions (J_ms=20.5±3.1μgh^-1cm^-2 SS-NE; 28.9±2.9μgh^-1cm^-2 L-NE) were significantly increased compared to an ethanolic control solution (J_ms=3.4±0.3μgh^-1cm^-2, p<0.05). No significant variations of conductance were observed after two hours of contact between the formulations and the mucosa. Simultaneously, the presystemic metabolization pattern was modified in the case of the nanoemulsions compared to the control solution. In conclusion, our data suggests that oil-in-water nanoemulsions prepared from SEDDS dispersions of medium-chain lipids could be promising formulations for enhancing oral delivery of resveratrol.

Anthoxanthin Polyphenols Attenuate Aβ Oligomer-induced Neuronal Responses Associated with Alzheimer's Disease

AIMS

Epidemiological evidence implicates polyphenols as potential natural therapeutics for Alzheimer's disease (AD). To investigate this prospect, five anthoxanthin polyphenols were characterized for their ability to reduce amyloid-β (Aβ) oligomer-induced neuronal responses by two mechanisms of action, modulation of oligomerization and antioxidant activity, as well as the synergy between these two mechanisms.

METHODS

Anthoxanthin oligomerization modulation and antioxidant capabilities were evaluated and correlated with anthoxanthin attenuation of oligomer-induced intracellular reactive oxygen species (ROS) and caspase activation using human neuroblastoma cell treatments designed to isolate these mechanisms of action and to achieve dual-action.

RESULTS

While modulation of oligomerization resulted in only minor reductions to neuronal responses, anthoxanthin antioxidant action significantly attenuated oligomer-induced intracellular ROS and caspase activation. Kaempferol uniquely exhibited synergism when the two mechanisms functioned in concert, leading to a pronounced reduction in both ROS and caspase activation.

CONCLUSIONS

Together, these findings identify the dominant mechanism by which these anthoxanthins attenuate Aβ oligomer-induced neuronal responses, elucidate their prospective synergy, and demonstrate the potential of anthoxanthin polyphenols as natural AD therapeutics.

Phenolic Compounds and Its Bioavailability: In Vitro Bioactive Compounds or Health Promoters?

Botanical preparations present a widespread and secular history of use. In fact, natural matrices possess a rich pool of phytochemicals, with promising biological effects. Among them, phenolic compounds have revealed to confer very important attributes to improve the well-being and longevity of worldwide population. Numerous in vitro studies have been carried out evaluating the wide spectrum of bioactivities of phenolic compounds, including its health effects, but through in vivo experiments some of these previous results cannot be properly confirmed, and considerable variations are observed. Pharmacokinetic parameters, including the assessment of bioavailability and bioefficacy of phenolic compounds, still continue to be largely investigated and considered a great hot topic among the food science and technology researchers. Thus, based on these crucial aspects, this chapter aims to provide an extensive approach about the question of the bioavailability of phenolic compounds, describing its biosynthetic routes and related mechanisms of action; to focus on the current facts and existing controversies, highlighting the importance of in vivo studies and the impact of phenolic compounds on the quality of life and longevity.

Resveratrol, piperine and apigenin differ in their NADPH-oxidase inhibitory and reactive oxygen species-scavenging properties

BACKGROUND

Many plant-derived chemicals have been studied for their potential benefits in ailments including inflammation, cancer, neurodegeneration, and cardiovascular disease. The health benefits of phytochemicals are often attributed to the targeting of reactive oxygen species (ROS). However, it is not always clear whether these agents act directly as antioxidants to remove ROS, or whether they act indirectly by blocking ROS production by enzymes such as NADPH oxidase (NOX) enzymes, or by influencing the expression of cellular pro- and anti- oxidants.

HYPOTHESIS/PURPOSE

Here we evaluate the pro- and anti-oxidant and NOX-inhibiting qualities of four phytochemicals: celastrol, resveratrol, apigenin, and piperine.

STUDY DESIGN

This work was done using the H661 cell line expressing little or no NOX, modified H661 cells expressing NOX1 and its subunits, and an EBV-transformed B-lymphoblastoid cell line expressing endogenous NOX2. ROS were measured using Amplex Red and nitroblue tetrazolium assays. In addition, direct ROS scavenging of hydrogen peroxide or superoxide generated were measured using Amplex Red and methyl cypridina luciferin analog (MCLA).

RESULTS

Of the four plant-derived compounds evaluated, only celastrol displayed NOX inhibitory activities, while celastrol and resveratrol both displayed ROS scavenging activity. Very little impact on ROS was observed with apigenin, or piperine.

CONCLUSION

The results of this study reveal the differences that exist between cell-free and intracellular pro-oxidant and antioxidant activities of several plant-derived compounds.

Fish oil attenuates neurologic severity of antiphospholipid syndrome in a mice experimental model

INTRODUCTION

Murine experimental models of antiphospholipid syndrome (eAPLS) showed neurologic dysfunction and therapeutic effect of the anticoagulant enoxaparin is well established. Omega-3 fatty acids and curcumin, tested in neuroinflammation and auto-immunity diseases, might be interesting therapeutic candidates. The aim of this study was to evaluate the effects of these candidates on neurologic severity in eAPLS.

METHODS

One month after immunization of BALB/c mice with beta-2-glycoprotein I, daily treatments were initiated with enoxaparin (1 mg/kg), omega-3 fatty acids (0.5 g/kg), and curcumin (200 mg/kg) for 3 months.

RESULTS

Mortality was significantly decreased by enoxaparin and omega-3 treatments. Fish oil and curcumin group exhibited the highest mean of swimming behavior in forced swim test in surviving mice. Mice under omega-3 fatty acids or curcumin presented low anxiety-like behavior in the elevated plus-maze test. Cerebral histopathology revealed heavy inflammatory infiltrates in cortical and subcortical regions with vacuolization, swelling, and degeneration of astrocytes in the control group, with aggravation under curcumin; no infiltrate was retrieved in enoxaparin and omega-3 groups.

CONCLUSION

Our study is the first to demonstrate a potential therapeutic effect of omega-3 fatty acids in eAPLS. Enoxaparin and omega-3 fatty acids combination would be interesting for further investigation.

Botanical Polyphenols Mitigate Microglial Activation and Microglia-Induced Neurotoxicity: Role of Cytosolic Phospholipase A2

Microglia play a significant role in the generation and propagation of oxidative/nitrosative stress, and are the basis of neuroinflammatory responses in the central nervous system. Upon stimulation by endotoxins such as lipopolysaccharides (LPS), these cells release pro-inflammatory factors which can exert harmful effects on surrounding neurons, leading to secondary neuronal damage and cell death. Our previous studies demonstrated the effects of botanical polyphenols to mitigate inflammatory responses induced by LPS, and highlighted an important role for cytosolic phospholipase A2 (cPLA2) upstream of the pro-inflammatory pathways (Chuang et al. in J Neuroinflammation 12(1):199, 2015. doi: 10.1186/s12974-015-0419-0 ). In this study, we investigate the action of botanical compounds and assess whether suppression of cPLA2 in microglia is involved in the neurotoxic effects on neurons. Differentiated SH-SY5Y neuroblastoma cells were used to test the neurotoxicity of conditioned medium from stimulated microglial cells, and WST-1 assay was used to assess for the cell viability of SH-SY5Y cells. Botanicals such as quercetin and honokiol (but not cyanidin-3-O-glucoside, 3CG) were effective in inhibiting LPS-induced nitric oxide (NO) production and phosphorylation of cPLA2. Conditioned medium from BV-2 cells stimulated with LPS or IFNγ caused neurotoxicity to SH-SY5Y cells. Decrease in cell viability could be ameliorated by pharmacological inhibitors for cPLA2 as well as by down-regulating cPLA2 with siRNA. Botanicals effective in inhibition of LPS-induced NO and cPLA2 phosphorylation were also effective in ameliorating microglial-induced neurotoxicity. Results demonstrated cytotoxic factors from activated microglial cells to cause damaging effects to neurons and potential use of botanical polyphenols to ameliorate the neurotoxic effects.

Polyphenolic Antioxidants and Neuronal Regeneration

Many studies indicate that oxidative stress is involved in the pathophysiology of neurodegenerative diseases. Oxidative stress can induce neuronal damages, modulate intracellular signaling and ultimately leads to neuronal death by apoptosis or necrosis. To review antioxidants preventive effects on oxidative stress and neurodegenerative diseases we accumulated data from international medical journals and academic informations’ sites. According to many studies, antioxidants could reduce toxic neuronal damages and many studies confirmed the efficacy of polyphenol antioxidants in fruits and vegetables to reduce neuronal death and to diminish oxidative stress. This systematic review showed the antioxidant activities of phytochemicals which play as natural neuroprotectives with low adverse effects against some neurodegenerative diseases as Parkinson or Alzheimer diseases.

Protective Effects of AGE and Its Components on Neuroinflammation and Neurodegeneration

Garlic (Allium sativum) is used for culinary and medicinal purposes in diverse cultures worldwide. When fresh garlic is soaked in aqueous ethanol under ambient environment over 4 months or longer, the majority of irritating taste and odor is eliminated and the antioxidant profile in the resulting aged garlic extract (AGE) changes significantly. Recently, AGE and its components have been demonstrated to exert neuroprotective effects in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and cerebral ischemia. Because of its health supporting potential, there is increasing interest in understanding the antioxidant and anti-inflammatory properties and the underlying mechanisms for its protective effects in heath and disease. There is evidence for AGE to exert its action on distinct signaling pathways associated with oxidative stress and neuroinflammation, although the primary molecular mechanisms remain unclear. By utilizing quantitative proteomic approaches, we demonstrated that AGE and two of its major ingredients, S-allyl-L-cysteine and N (α)-(1-deoxy-D-fructos-1-yl)-L-arginine, can attenuate neuroinflammatory responses in microglial cells through modulation of Nrf2-mediated signaling as well as other oxidative stress-related pathways. These experimental data provide information for the molecular targets of AGE and its components to mitigate neurodegeneration and neuroinflammation and show a promising potential of these compounds as dietary supplements for health maintenance.

Neuroprotection and antioxidants

Ischemia as a serious neurodegenerative disorder causes together with reperfusion injury many changes in nervous tissue. Most of the neuronal damage is caused by complex of biochemical reactions and substantial processes, such as protein agregation, reactions of free radicals, insufficient blood supply, glutamate excitotoxicity, and oxidative stress. The result of these processes can be apoptotic or necrotic cell death and it can lead to an irreversible damage. Therefore, neuroprotection and prevention of the neurodegeneration are highly important topics to study. There are several approaches to prevent the ischemic damage. Use of many modern therapeutical methods and the incorporation of several substances into the diet of patients is possible to stimulate the endogenous protective mechanisms and improve the life quality.

Withania somnifera and Its Withanolides Attenuate Oxidative and Inflammatory Responses and Up-Regulate Antioxidant Responses in BV-2 Microglial Cells

Withania somnifera (L.) Dunal, commonly known as Ashwagandha, has been used in Ayurvedic medicine for promoting health and quality of life. Recent clinical trials together with experimental studies indicated significant neuroprotective effects of Ashwagandha and its constituents. This study is aimed to investigate anti-inflammatory and anti-oxidative properties of this botanical and its two withanolide constituents, namely, Withaferin A and Withanolide A, using the murine immortalized BV-2 microglial cells. Ashwagandha extracts not only effectively inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and reactive oxygen species (ROS) production in BV-2 cells, but also stimulates the Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway, leading to induction of heme oxygenase-1 (HO-1), both in the presence and absence of LPS. Although the withanolides were also capable of inhibiting LPS-induced NO production and stimulating Nrf2/HO-1 pathway, Withaferin A was tenfold more effective than Withanolide A. In serum-free culture, LPS can also induce production of long thin processes (filopodia) between 4 and 8 h in BV-2 cells. This morphological change was significantly suppressed by Ashwagandha and both withanolides at concentrations for suppressing LPS-induced NO production. Taken together, these results suggest an immunomodulatory role for Ashwagandha and its withanolides, and their ability to suppress oxidative and inflammatory responses in microglial cells by simultaneously down-regulating the NF-kB and upregulating the Nrf2 pathways.

Phytopharmacologic preparations as predictors of plant bioactivity: A particular approach to Echinacea purpurea (L.) Moench antioxidant properties

OBJECTIVE

A large body of evidence has confirmed a multitude of health benefits of plant products and their derived formulations. Echinacea purpurea (L.) Moench is a good example, widely used due to its therapeutic properties. In the present study, the chemical composition of the different samples and antioxidant properties of E. purpurea hydroethanolic and aqueous extracts obtained from dry or fresh raw material were evaluated and compared with dietary supplements based on the same plant (tablets and syrup), to determine the most active phytopharmacologic preparation or formulation.

METHODS

Chemical composition of the different samples was assessed through the determination of free sugars, organic acids and tocopherols. The in vitro antioxidant properties were determined using four assays: 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging activity, reducing power, inhibition of b-carotene bleaching and inhibition of lipid peroxidation by thiobarbituric acid reactive substances (TBARS) assay. Total phenolics and flavonoids were also determined.

RESULTS

Overall, the hydroethanolic extract of fresh plant revealed the highest activity, directly related with its higher contents in phenolic (229.22 ± 4.38 mg gallic acid equivalent [GAE]/mL), flavonoids (124.83 ± 7.47 mg GAE/mL), organic acids (8.89 ± 0.10 g/100 g), and tocopherols (4.55 ± 0.02 mg/100 g). Tablets followed by syrup revealed the worst effect, positively correlated with the lowest abundance in bioactive molecules. The weak in vitro antioxidant potential of commercial phytopharmacologic formulations could be related to their chemical composition, including the addition of excipients.

CONCLUSION

Further studies are necessary to deepen knowledge on this area, namely focusing on in vivo experiments, to establish upcoming guidelines to improve the quality and bioavailability of phytopharmacologic formulations.

Protective effects of Egyptian cloudy apple juice and apple peel extract on lipid peroxidation, antioxidant enzymes and inflammatory status in diabetic rat pancreas

Background

Apples possess rich content of varied polyphenolic compounds showing a variety of biological activities that may ascribe to worthy effects against some chronic diseases. The present study was designed to assess the protective effects of the cloudy apple juice (CAJ) and apple peel extract (APE) of Egyptian Anna apple on the complications in experimental diabetes.

Materials and methods

Four groups were studied. Diabetes was induced by a single dose of streptozotocin (STZ) to only three groups of albino Wistar rats. Two of the diabetic groups received either CAJ or APE for 21 days. At the end of the study, lipid profile parameters were measured in serum while lipid peroxidation (LPO) level, antioxidant enzyme activities and inflammatory markers were evaluated in pancreas tissue samples. The gas chromatography–mass spectrometry (GC-MS) analysis of phenolic compounds found in CAJ and APE was carried out. Moreover, total phenolic content of CAJ and APE were measured.

Results

The significant increase of blood glucose level, serum total cholesterol (TC), triglycerides (TG), low- density lipoprotein cholesterol (LDL-C), and very low-density lipoprotein (VLDL) levels, in addition to tissue malondialdehyde (MDA), nuclear factor kappa B (NF-kB), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8) levels, but a significant decrease in high-density lipoprotein cholesterol (HDL-C), and the activity of pancreatic antioxidant enzymes were the remarkably parameters observed in diabetic control rats. Dissimilarly, oral supplementation of 15 ml/kg CAJ and 1 g/kg APE for 21 days resulted in a significant decrease in fasting blood glucose, serum TC, TG, LDL-C, VLDL-C and tissue MDA, NF-kB, TNF-α, IL-6, IL-8 levels coupled with a significant elevation of HDL-C and antioxidant enzymes’ activity when compared with diabetic control animals.

Conclusions

The results indicate that Egyptian CAJ and APE supplementation may have protective effects against deleterious complications of diabetes mellitus.

Quercetin Attenuates Inflammatory Responses in BV-2 Microglial Cells: Role of MAPKs on the Nrf2 Pathway and Induction of Heme Oxygenase-1

A large group of flavonoids found in fruits and vegetables have been suggested to elicit health benefits due mainly to their anti-oxidative and anti-inflammatory properties. Recent studies with immune cells have demonstrated inhibition of these inflammatory responses through down-regulation of the pro-inflammatory pathway involving NF-κB and up-regulation of the anti-oxidative pathway involving Nrf2. In the present study, the murine BV-2 microglial cells were used to compare anti-inflammatory activity of quercetin and cyanidin, two flavonoids differing by their alpha, beta keto carbonyl group. Quercetin was 10 folds more potent than cyanidin in inhibition of lipopolysaccharide (LPS)-induced NO production as well as stimulation of Nrf2-induced heme-oxygenase-1 (HO-1) protein expression. In addition, quercetin demonstrated enhanced ability to stimulate HO-1 protein expression when cells were treated with LPS. In an attempt to unveil mechanism(s) for quercetin to enhance Nrf2/HO-1 activity under endotoxic stress, results pointed to an increase in phospho-p38MAPK expression upon addition of quercetin to LPS. In addition, pharmacological inhibitors for phospho-p38MAPK and MEK1/2 for ERK1/2 further showed that these MAPKs target different sites of the Nrf2 pathway that regulates HO-1 expression. However, inhibition of LPS-induced NO by quercetin was not fully reversed by TinPPIX, a specific inhibitor for HO-1 activity. Taken together, results suggest an important role of quercetin to regulate inflammatory responses in microglial cells and its ability to upregulate HO-1 against endotoxic stress through involvement of MAPKs.

Plant-derived neuroprotective agents in Parkinson's disease

Parkinson's disease (PD) is one of the most common degenerative disorders of the central nervous system among the elderly. The disease is caused by the slow deterioration of the dopaminergic neurons in the substantia nigra. Treatment strategies to protect dopaminergic neurons from progressive damage have received much attention. However there is no effective treatment for PD. Traditional Chinese medicines have shown potential clinical efficacy in attenuating the progression of PD. Increasing evidence indicates that constituents of some Chinese herbs include resveratrol, curcumin, and ginsenoside can be neuroprotective. Since pathologic processes in PD including inflammation, oxidative stress, apoptosis, mitochondrial dysfunction, and genetic factors lead to neuronal degeneration, and these Chinese herbs can protect dopaminergic neurons from neuronal degeneration, in this article, we review the neuroprotective roles of these herbs and summarize their anti-inflammatory, antioxidant, and anti-apoptotic effects in PD. In addition, we discuss their possible mechanisms of action in in vivo and in vitro models of PD. Traditional Chinese medicinal herbs, with their low toxicity and side-effects, have become the potential therapeutic interventions for prevention and treatment of PD and other neurodegenerative diseases.

Protective effects of epigallocatechin-3-gallate on intestinal ischemia reperfusion injury through enhanced activation of PI3K/Akt pathway in rats

Inflammation plays a critical role in intestinal ischemia reperfusion injury (IRI). Epigallocatechin-3-gallate (EGCG) has been demonstrated to possess anti-inflammatory effect. This study examined the effect of EGCG on intestinal IRI and explored the possible mechanisms. Male Wistar rats were randomly divided into three groups: sham-operated group (Sham), IRI control group (IRI) and IRI-EGCG group (EGCG). Rats in IRI-EGCG group were administered dissolved EGCG in drinking water (0.4 mg/mL) for 14 days prior to IRI induction. A rat model of intestinal IRI was established by ligating the superior mesenteric artery (SMA) for 30 min, followed by reperfusion for 1 h. Intestinal histology, pro-inflammatory cytokines and mediators were examined and the effect of EGCG on PI3K/Akt signalling was assessed. EGCG significantly alleviated the pathological changes of the intestine and suppressed the IRI-induced up-regulation of TNF-α, IL-1 and IL-6 mRNA and protein expression in the serum and intestine. The mechanism might be that EGCG enhanced the activation of PI3K/Akt signalling pathway. In conclusion, the administration of EGCG can significantly mitigate the acute intestinal IRI in rats by enhancing the activation of PI3K/Akt signalling pathway to suppress inflammatory response and might be a promising alternative for the prevention or treatment of intestinal IRI in the clinical practice.

Activity of liver enzymes in multiple sclerosis patients with Hot-nature diet and co-supplemented hemp seed, evening primrose oils intervention

BACKGROUND

It is unknown whether diets with a high dietary total antioxidant capacity (TAC) can modify oxidative stress, low-grade inflammation, or liver dysfunction, all of which are risk factors for multiple sclerosis disease. This study assesses alanine amino-transferase (ALT), aspartate-aminotransferase (AST) and gamma-glutamyl transferase (GGT) activities in MS patients treated with co-supplemented hemp seed and evening primrose oils as well as Hot-nature diet and the therapeutic potential this intervention.

METHODS AND MATERIALS

In this double blind, randomized trial, 100 MS patients with EDSS<6 were allocated into 3 groups: "group A", who received co-supplemented hemp seed and evening primrose oils with advised Hot-nature diet; "group B",who received olive oil; and "group C", who received the co-supplemented oils. Clinically, EDSS as well as serum level of liver enzymes (GGT, AST, and ALT) were assessed at baseline and after 6 months.

RESULTS

Mean follow-up was 180±2.9 SD days (N=65, 23 M and 42 F aged 34.25±8.07 years with disease duration of 6.80±4.33 years). There was no significant difference in the study parameters at baseline. Serum levels of liver enzymes (GGT, AST, and ALT) were serially monitored. Intervention was associated with liver function alteration in three groups. Significance decreased in EDSS score and the levels of liver enzymes were found in groups A and C, whereas elevated serum liver enzymes and EDSS score were observed in group B after the intervention.

CONCLUSION

Selecting foods according to their Total antioxidant capacity such as co-supplemented hemp seed and evening primrose oils with Hot-nature diet affects antioxidant intake and can have beneficial effects on improving EDSS score and activity of liver enzymes in RRMS patients.

Dietary Sutherlandia and elderberry mitigate cerebral ischemia-induced neuronal damage and attenuate p47phox and phospho-ERK1/2 expression in microglial cells

Sutherlandia (Sutherlandia frutescens) and elderberry (Sambucus spp.) are used to promote health and for treatment of a number of ailments. Although studies with cultured cells have demonstrated antioxidative and anti-inflammatory properties of these botanicals, little is known about their ability to mitigate brain injury. In this study, C57BL/6 J male mice were fed AIN93G diets without or with Sutherlandia or American elderberry for 2 months prior to a 30-min global cerebral ischemia induced by occlusion of the bilateral common carotid arteries (BCCAs), followed by reperfusion for 3 days. Accelerating rotarod assessment at 24 h after BCCA occlusion showed amelioration of sensorimotor impairment in the mice fed the supplemented diets as compared with the ischemic mice fed the control diet. Quantitative digital pathology assessment of brain slides stained with cresyl violet at 3 days after ischemia/reperfusion (I/R) revealed significant reduction in neuronal cell death in both dietary groups. Immunohistochemical staining for ionized calcium-binding adapter molecule-1 demonstrated pronounced activation of microglia in the hippocampus and striatum in the ischemic brains 3 days after I/R, and microglial activation was significantly reduced in animals fed supplemented diets. Mitigation of microglial activation by the supplements was further supported by the decrease in expression of p47phox, a cytosolic subunit of NADPH oxidase, and phospho-ERK1/2, a mitogen-activated protein kinase known to mediate a number of cytoplasmic processes including oxidative stress and neuroinflammatory responses. These results demonstrate neuroprotective effect of Sutherlandia and American elderberry botanicals against oxidative and inflammatory responses to cerebral I/R.

Resveratrol protects against cigarette smoke-induced oxidative damage and pulmonary inflammation

This study was carried out to investigate the effects of resveratrol on cigarette smoke (CS)-induced lung injury. Experimental mice were administrated with 1 mg/kg or 3 mg/ kg resveratrol orally, 1 h prior to CS exposure (five cigarettes a day for 3 consecutive days). Airway inflammation and gene expression changes were assessed. CS exposure increased the number of pulmonary inflammatory cells, coupled with elevated production of tumor necrosis factor α and interleukin-6 in bronchoalveolar lavage fluids. Resveratrol treatment decreased CS-induced lung inflammation. Resveratrol restored the activities of superoxide dismutase, GSH peroxidase, and catalase in CS-treated mice. CS significantly enhanced the nuclear translocation of nuclear factor κB (NF-κB) and NF-κB DNA binding activity, which was impaired by resveratrol pretreatment. In addition, resveratrol promoted CS-induced heme oxygenase-1 (HO-1) expression and activation. Our results collectively indicate that resveratrol attenuates CS-induced lung oxidative injury, which involves decreased NF-κB activity and the elevated HO-1 expression and activity.

Neuroprotective effects of resveratrol in Alzheimer disease pathology

Alzheimer's disease is a chronic neurodegenerative disorder characterized by a progressive loss of cognitive and behavioral abilities. Extracellular senile plaques and intracellular neurofibrillary tangles are hallmarks of AD. Researchers aim to analyze the molecular mechanisms underlying AD pathogenesis; however, the therapeutic options available to treat this disease are inadequate. In the past few years, several studies have reported interesting insights about the neuroprotective properties of the polyphenolic compound resveratrol (3, 5, 4'-trihydroxy-trans-stilbene) when used with in vitro and in vivo models of AD. The aim of this review is to focus on the neuroprotective and antioxidant effects of resveratrol on AD and its multiple potential mechanisms of action. In addition, because the naturally occurring forms of resveratrol have a very limited half-life in plasma, a description of potential analogs aimed at increasing the bioavailability in plasma is also discussed.

An optimal dose of tea polyphenols protects against global cerebral ischemia/reperfusion injury

Previous studies addressing the protection of tea polyphenols against cerebral ischemia/reperfusion injury often use focal cerebral ischemia models, and the optimal dose is not unified. In this experiment, a cerebral ischemia/reperfusion injury rat model was established using a modified four-vessel occlusion method. Rats were treated with different doses of tea polyphenols (25, 50, 100, 150, 200 mg/kg) via intraperitoneal injection. Results showed that after 2, 6, 12, 24, 48 and 72 hours of reperfusion, peroxide dismutase activity and total antioxidant capacity in brain tissue gradually increased, while malondialdehyde content gradually decreased after tea polyphenol intervention. Tea polyphenols at 200 mg/kg resulted in the most apparent changes. Terminal deoxynucleotidyl transferase-mediated nick end labeling and flow cytometry showed that 200 mg/kg tea polyphenols significantly reduced the number and percentage of apoptotic cells in the hippocampal CA1 region of rats after cerebral ischemia/reperfusion injury. The open field test and elevated plus maze experiments showed that tea polyphenols at 200 mg/kg strengthened exploratory behavior and reduced anxiety of cerebral ischemia/reperfusion injured rats. Experimental findings indicate that tea polyphenols protected rats against cerebral ischemia/reperfusion injury and 200 mg/kg is regarded as the optimal dose.

Resveratrol protects against homocysteine-induced cell damage via cell stress response in neuroblastoma cells

Recent findings underscore that some natural compounds are responsible for specific biochemical effects, i.e., the activation of redox-sensitive intracellular pathways and modulation of different stress proteins, such as heat shock proteins and sirtuins. Resveratrol, a natural polyphenol widely present in plants, has been shown to display various beneficial effects, including neuroprotection, in several pathological conditions. In the present study, by using differentiated SH-SY5Y neuroblastoma cells, we investigated the potential protective effects of resveratrol against homocysteine-induced neurotoxicity. We observed that homocysteine (100 µM) decreased cell viability while at the same time significantly increasing intracellular reactive oxygen species and DNA fragmentation. Cell pretreatment with resveratrol concentrations ranging from 1 to 5 µM elicited protective effects through the reduction of oxidative stress and genotoxic damage. In addition, we observed that resveratrol produced significant changes in the expression of both Hsp70 and sirtuin 1 (SIRT1). After homocysteine treatment in the presence of resveratrol, SIRT1 protein was found abundantly not only in the cytosol but also in the nucleus, as demonstrated by confocal laser scanning microscopy. The results of this study suggest that resveratrol is a potential protective agent against homocysteine-induced neurotoxicity and that beneficial effects are accompanied by changes in cell stress response. Taken together, these features contribute to our knowledge of underlying mechanisms involved in resveratrol-induced cell survival.

NitroDIGE analysis reveals inhibition of protein S-nitrosylation by epigallocatechin gallates in lipopolysaccharide-stimulated microglial cells

Background

Nitric oxide (NO) is a signaling molecule regulating numerous cellular functions in development and disease. In the brain, neuronal injury or neuroinflammation can lead to microglial activation, which induces NO production. NO can react with critical cysteine thiols of target proteins forming S-nitroso-proteins. This modification, known as S-nitrosylation, is an evolutionarily conserved redox-based post-translational modification (PTM) of specific proteins analogous to phosphorylation. In this study, we describe a protocol for analyzing S-nitrosylation of proteins using a gel-based proteomic approach and use it to investigate the modes of action of a botanical compound found in green tea, epigallocatechin-3-gallate (EGCG), on protein S-nitrosylation after microglial activation.

Methods/Results

To globally and quantitatively analyze NO-induced protein S-nitrosylation, the sensitive gel-based proteomic method, termed NitroDIGE, was developed by combining two-dimensional differential in-gel electrophoresis (2-D DIGE) with the modified biotin switch technique (BST) using fluorescence-tagged CyDye™ thiol reactive agents to label S-nitrosothiols. The NitroDIGE method showed high specificity and sensitivity in detecting S-nitrosylated proteins (SNO-proteins). Using this approach, we identified a subset of SNO-proteins ex vivo by exposing immortalized murine BV-2 microglial cells to a physiological NO donor, or in vivo by exposing BV-2 cells to endotoxin lipopolysaccharides (LPS) to induce a proinflammatory response. Moreover, EGCG was shown to attenuate S-nitrosylation of proteins after LPS-induced activation of microglial cells primarily by modulation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response.

Conclusions

These results demonstrate that NitroDIGE is an effective proteomic strategy for “top-down” quantitative analysis of protein S-nitrosylation in multi-group samples in response to nitrosative stress due to excessive generation of NO in cells. Using this approach, we have revealed the ability of EGCG to down-regulate protein S-nitrosylation in LPS-stimulated BV-2 microglial cells, consistent with its known antioxidant effects.

Subchronic apocynin treatment attenuates methamphetamine-induced dopamine release and hyperactivity in rats

AIMS

The effects of methamphetamine are linked to stimulation of dopaminergic neurons, which can be accompanied by production of reactive oxygen species (ROS). Apocynin (4-hydroxy-3-methoxy-acetophenone) is a nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase (NOX) inhibitor shown to mitigate oxidative stress in a number of models. The present study aimed at testing whether apocynin suppresses the dopamine-releasing and locomotor-activating properties of methamphetamine.

MAIN METHODS

(1) Apocynin (0.01-100μM) was applied to rat striatal slices preloaded with [(3)H]dopamine and its efficacy to evoke [(3)H]overflow and to alter methamphetamine (3μM)-evoked [(3)H]overflow was measured. (2) Groups of rats received apocynin (15 or 50mg/kg/day) or vehicle injection for seven consecutive days, and the efficacy and potency of methamphetamine to evoke [(3)H]overflow were determined. (3) Groups of apocynin-treated rats were administered methamphetamine (0.5 or 1mg/kg) or saline to determine the effect of apocynin on stimulant-induced hyperactivity.

KEY FINDINGS

(1) Apocynin applied to striatal slices did not evoke [(3)H]overflow or alter methamphetamine-evoked [(3)H]overflow. (2) However, subchronic apocynin treatment significantly and dose-dependently decreased methamphetamine's potency and efficacy to evoke [(3)H]overflow. (3) Subchronic apocynin treatment also decreased the locomotor activity evoked by methamphetamine.

SIGNIFICANCE

Subchronic apocynin treatment diminished methamphetamine induced dopamine-release and its locomotor-activating properties. The pattern of results indicates that apocynin is more effective after repeated, rather than after acute, treatment. The findings also suggest that NOX inhibitors or agents suppressing oxidative stress may constitute a new area for research to understand how methamphetamine produces its deleterious and neurotoxic outcomes in the brain.

Diet and cognition: interplay between cell metabolism and neuronal plasticity

PURPOSE OF STUDY

To discuss studies in humans and animals revealing the ability of foods to benefit the brain: new information with regards to mechanisms of action and the treatment of neurological and psychiatric disorders.

RECENT FINDINGS

Dietary factors exert their effects on the brain by affecting molecular events related to the management of energy metabolism and synaptic plasticity. Energy metabolism influences neuronal function, neuronal signaling, and synaptic plasticity, ultimately affecting mental health. Epigenetic regulation of neuronal plasticity appears as an important mechanism by which foods can prolong their effects on long-term neuronal plasticity.

SUMMARY

The prime focus of the discussion is to emphasize the role of cell metabolism as a mediator for the action of foods on the brain. Oxidative stress promotes damage to phospholipids present in the plasma membrane such as the omega-3 fatty acid docosahexenoic acid, disrupting neuronal signaling. Thus, dietary docosahexenoic acid seems crucial for supporting plasma membrane function, interneuronal signaling, and cognition. The dual action of brain-derived neurotrophic factor in neuronal metabolism and synaptic plasticity is crucial for activating signaling cascades under the action of diet and other environmental factors, using mechanisms of epigenetic regulation.

Effects of Resveratrol and trans-3,5,4'-Trimethoxystilbene on Glutamate-Induced Cytotoxicity, Heme Oxygenase-1, and Sirtuin 1 in HT22 Neuronal Cells

Resveratrol (trans-3,5,4’-trihydroxystilbene) has received considerable attention recently for the potential neuroprotective effects in neurodegenerative disorders where heme oxygenase-1 (HO-1) and sirtuin 1 (SIRT1) represent promising therapeutic targets. Resveratrol has been known to increase HO-1 expression and SIRT1 activity. In this study, the effects of resveratrol and trans-3,5,4’-trimethoxystilbene (TMS), a resveratrol derivative, on cytotoxicity caused by glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation have been investigated by using murine hippocampal HT22 cells, which have been widely used as an in vitro model for investigating glutamate-induced neurotoxicity. Resveratrol protected HT22 neuronal cells from glutamateinduced cytotoxicity and increased HO-1 expression as well as SIRT1 activity in a concentration-dependent manner. Cytoprotec-tion afforded by resveratrol was partially reversed by the specific inhibition of HO-1 expression by HO-1 small interfering RNA and the nonspecific blockage of HO-1 activity by tin protoporphyrin IX, but not by SIRT1 inhibitors. Surprisingly, TMS, a resveratrol derivative with methoxyl groups in lieu of the hydroxyl groups, and trans-stilbene, a non-hydroxylated analog, failed to protect HT22 cells from glutamate-induced cytotoxicity and to increase HO-1 expression and SIRT1 activity. Taken together, our findings suggest that the cytoprotective effect of resveratrol was at least in part associated with HO-1 expression but not with SIRT1 activation and, importantly, that the presence of hydroxyl groups on the benzene rings of resveratrol appears to be necessary for cytoprotection against glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation in HT22 neuronal cells.

Carbonyl stress in aging process: role of vitamins and phytochemicals as redox regulators

There is a growing scientific agreement that the cellular redox regulators such as antioxidants, particularly the natural polyphenolic forms, may help lower the incidence of some pathologies, including metabolic diseases like diabetes and diabesity, cardiovascular and neurodegenerative abnormalities, and certain cancers or even have anti-aging properties. The recent researches indicate that the degree of metabolic modulation and adaptation response of cells to reductants as well as oxidants establish their survival and homeostasis, which is linked with very critical balance in imbalances in cellular redox capacity and signaling, and that might be an answer the questions why some antioxidants or phytochemicals potentially could do more harm than good, or why some proteins lose their function by increase interactions with glyco- and lipo-oxidation mediates in the cells (carbonyl stress). Nonetheless, pursue of healthy aging has led the use of antioxidants as a means to disrupt age-associated physiological dysfunctions, dysregulated metabolic processes or prevention of many age-related diseases. Although it is still early to define their exact clinical benefits for treating age-related disease, a diet rich in polyphenolic or other forms of antioxidants does seem to offer hope in delaying the onset of age-related disorders. It is now clear that any deficiency in antioxidant vitamins, inadequate enzymatic antioxidant defenses can distinctive for many age-related disease, and protein carbonylation can used as an indicator of oxidative stress associated diseases and aging status. This review examines antioxidant compounds and plant polyphenols as redox regulators in health, disease and aging processes with hope that a better understanding of the many mechanisms involved with these distinct compounds, which may lead to better health and novel treatment approaches for age-related diseases.

Repeated resveratrol treatment attenuates methamphetamine-induced hyperactivity and [3H]dopamine overflow in rodents

Resveratrol (3,4',5-trihydroxy-trans-stilbene) has been investigated for its potential as a prophylactic against degenerative diseases. It is a sirtulin activator that has recently been shown to regulate dopaminergic systems that contribute to the behavioral effects of methamphetamine and cocaine. The present study examined the impact of resveratrol on stimulant neuropsychopharmacology in rodents. Acute resveratrol treatment (20-40mg/kg) was ineffective to alter methamphetamine (0.5mg/kg)-induced hyperactivity in mice. Rodents received resveratrol once-daily for seven days to determine the effect of repeated polyphenolic treatment. Repeated resveratrol treatment (1-20mg/kg) decreased methamphetamine (0.5mg/kg)-induced hyperactivity in mice. Methamphetamine's (0.1-60μM) efficacy to evoke [(3)H]overflow from rat striatal slices preloaded with [(3)H]dopamine was also attenuated by repeated resveratrol (1mg/kg) treatment. Repeated resveratrol treatment (10-20mg/kg) did not affect cocaine-induced hyperactivity in mice. Overall, these data suggest that resveratrol appears to have metaplastic and prophylactic activity to minimize the effects of methamphetamine to increase locomotor activity and evoke dopamine release. These data encourage future research to further investigate the relationship between polyphenolics and psychostimulant abuse and dependence.

Chemical analysis and effect of blueberry and lingonberry fruits and leaves against glutamate-mediated excitotoxicity

Phenolic compounds are a large class of phytochemicals that are widespread in the plant kingdom and known to have antioxidant capacities. This study aimed to determine the antioxidant capacities as well as the content of total soluble phenolics, anthocyanins, tannins, and flavonoids in the fruits and leaves of blueberries and lingonberries growing in Newfoundland. This study also determined the potential neuroprotective effect of extracts from fruits and leaves against glutamate-mediated excitotoxicity, which is believed to contribute to disorders such as stroke and neurodegenerative diseases. Lingonberry and blueberry plants were found to be rich sources of phenolic compounds. Total antioxidant capacities in terms of radical scavenging activity and reducing power were much higher in leaves of both plants as compared to their fruits. These results were in correlation with phenolic contents including total flavonoids, anthocyanins, and tannins. Brain-derived cell cultures from rats were prepared and grown for about 2 weeks. Cell cultures were treated with glutamate (100 μM) for 24 h, and the effect of extracts was determined on cells subjected to this excitotoxicity. Glutamate treatment caused approximately 23% cell loss when measured after 24 h of exposure. Whereas lingonberry fruit extract did not provide protection from glutamate toxicity, blueberry fruit extracts were extremely protective. Leaf extracts of both lingonberry and blueberry showed a significant neuroprotective effect. The greater protective effect of leaf extracts was in correlation with the levels of phenolics and antioxidant capacity. These findings suggest that berries or their components may contribute to protecting the brain from various pathologies.

Antioxidant effect of organic purple grape juice on exhaustive exercise

This study aimed to assess the potential protective effect of organic purple grape juice (PGJ) on oxidative stress produced by an exhaustive exercise bout in rats. To test this hypothesis, rats were acutely treated with organic PGJ (Vitis labrusca) and subsequently submitted to an exhaustive exercise bout. Parameters of oxidative stress, such as thiobarbituric acid reactive species (TBARS) levels, 2′,7′,-dichlorofluorescein diacetate (DCFH-DA) oxidation, and nonprotein sulfhydryl levels (NP-SH) in the brain, skeletal muscle, and blood, were evaluated. Enzyme activity of Na+,K+-ATPase, Ca2+-ATPase, and δ-aminolevulinate dehydratase (δ-ALA-D) in the brain, skeletal muscle, and blood were also assayed. Statistical analysis showed that the exhaustive exercise bout increased TBARS levels and DCFH-DA oxidation, and decreased NP-SH levels in rat tissue. Ca2+-ATPase activity was increased in groups exposed to both exercise and PGJ treatment. The results indicate that organic PGJ intake was able to protect against the oxidative damage caused by an exhaustive exercise bout in different rat tissues.

Decalepis hamiltonii root extract attenuates the age-related decline in the cognitive function in Drosophila melanogaster

Age-associated accumulation of oxidative damage linked to decline of antioxidant defense mechanism, leads to impairment of cognitive function in many organisms. These damages can pass through generations and affect the cognitive quality of progenies. In Drosophila, classical olfactory conditioning results in the formation of different types of memory. Age-related memory impairment (AMI) causes reduction in middle term memory (MTM) and parental senescence causes decline in short-term memory (STM) of the offspring. We have further examined the neuromodulatory effect of Decalepis hamiltonii (Dh) root extract, which is a cocktail of novel antioxidant molecules, on the biochemical oxidative defenses in relation to cognitive ability of the aged flies and their offspring. There is a strong correlation between the age-related decline in the activity of the antioxidant enzymes and the lower cognitive ability of the aged flies and their offspring. Feeding of aged flies in the diet containing 0.1% Dh, markedly enhances the cognitive ability of both aged flies and their offspring which is associated with enhanced antioxidant defenses as evident for the activity of superoxide dismutase (SOD) and catalase. Our findings, for the first time, show that the antioxidant-rich Dh root extract attenuates the age-related decline in cognitive ability of Drosophila, and also shows ameliorative effect on the memory of the offspring.

Effect of plant phenolic compounds on biofilm formation by Pseudomonas aeruginosa

In the natural environment, bacteria predominantly exist in matrix-enclosed multicellular communities associated with various surfaces, referred to as biofilms. Bacteria in biofilms are extremely resistant to antibacterial agents thus causing serious problems for antimicrobial therapy. In this study, we showed that different plant phenolic compounds, at concentrations that did not or weakly suppressed bacterial growth, increased the capacity of Pseudomonas aeruginosa PAO1 to form biofilms. Biofilm formation of P. aeruginosa PAO1 was enhanced 3- to 7-fold under the action of vanillin and epicatechin, and 2- to 2.5-fold in the presence of 4-hydroxybenzoic, gallic, cinnamic, sinapic, ferulic, and chlorogenic acids. At higher concentrations, these compounds displayed an inhibiting effect. Similar experiments carried out for comparison with Agrobacterium tumefaciens C58 showed the same pattern. Vanillin, 4-hydroxybenzoic, and gallic acids at concentrations within the range of 40 to 400 μg/mL increased the production of N-3-oxo-dodecanoyl-homoserine lactone in P. aeruginosa PAO1 which suggests a possible relationship between stimulation of biofilm formation and Las Quorum Sensing system of this bacterium. Using biosensors to detect N-acyl-homoserine lactones (AHL), we demonstrated that the plant phenolics studied did not mimic AHLs.

Trace element, antioxidant activity, and lipid peroxidation levels in brain cortex of gerbils after cerebral ischemic injury

Proper trace element level and antioxidant enzyme activity are crucial for the brain in maintaining normal neurological functions. To our knowledge, alteration of lipid peroxidation status, trace element level, and antioxidant activity in the homogenates of brain cortex after cerebral ischemia in gerbil, however, has not been investigated so far. Male Mongolian gerbils were divided into control and ischemic subjects. Cerebral ischemia was induced by occlusion of the right middle cerebral artery and right common carotid artery for 1 h. Experimental results showed that a significant increase (P < 0.01) of the malondialdehyde level was found in the ischemic brain as compared with the control group. Trace element analysis indicated that a remarkable elevation (P < 0.01) of the level of iron (Fe), chromium (Cr), and a statistical decrease of selenium (Se) and zinc (Zn) (P < 0.05) concentration were observed in the ischemic brain as compared with the control subject. No significant change (P > 0.05) of the copper (Cu) level was found in both experimental groups. Additionally, antioxidant activity of superoxide dismutase (P < 0.01) and catalase (P < 0.05) was significantly decreased in the ischemic brain as compared with the control subject. Taking all results together, it is conceivable to manifest the experimental findings that cerebral ischemia not only may result in an enhanced oxidative stress but also may lead to further oxidative injury. Moreover, disturbance of trace element level combined with declined antioxidant activity seems to play a significant role in responsible for the etiology of cerebral ischemia.

Protective effects of resveratrol on glutamate-induced damages in murine brain cultures

Resveratrol interacts with the complex III of the respiratory chain, is a radical scavenger and also suppressor of radical formation in the mitochondria. It reduces the intracellular calcium levels in pre- and postsynaptic neurons and also may inhibit the pro-apoptotic factors in glutamate overflow that occurs, e.g. in excitotoxicity. In cell cultures, glutamate overflow leads to formation of free radicals and results in apoptosis. This increase of radical concentration is enhanced by influx of cations like iron or copper ions into the cell. In present study, the beneficial action of resveratrol was investigated in glutamate-affected dissociated cultures of mice mesencephalic primary cultures. On the 10th day in vitro, 5 mM of glutamate was administered for 15 min and the cultures were further maintained in medium containing 0, 0.01, 0.1 or 1 μM of resveratrol. Resveratrol reduced glutamate-induced damages. The number of dopaminergic neurons was increased and their morphology ameliorated when resveratrol followed glutamate treatment. A significant reduction of glutamate-induced radical formation in cultures treated with resveratrol corresponded with a considerable high antioxidative potential of this stilbene determined using the DPPH assay. In addition, ICP-OES was set up to measure the tissues' copper and iron contents in organotypic cortical cultures of glutamate treated (0 or 30 μM) slices and those in which resveratrol (0, 0.01, 0.1 or 1 μM) was co-administered. Levels of copper were dose-dependently increased, and also the concentration of iron was higher in resveratrol-treated organotypic cultures. The hypothesis that resveratrol has beneficial actions against glutamate damages was verified.

Therapeutic potential of treatment with the flavonoid rutin after cortical focal ischemia in rats

Flavonoids have known anti-inflammatory and antioxidative actions, and they have been described as neuroprotective and able to reduce damage in CNS diseases. We evaluated the action of the flavonoid rutin in an animal model of focal cortical ischemia induced by unilateral thermocoagulation of superficial blood vessels of motor (M1) and somatosensory (S1) primary cortices. Ischemic rats were submitted to daily injections (i.p.) for five days, starting immediately after induction of ischemia. We tested two doses: 50mg/kg or 100mg/kg of body weight. Sensorimotor tests were used to evaluate functional recovery. Bioavailability in plasma was done by chromatographic analysis. The effect of treatment in lesion volume and neurodegeneration was evaluated 48 h and 72 h after ischemia, respectively. We observed significant sensorimotor recovery induced by rutin, and the dose of 50mg/kg had more pronounced effect. Thus, this dose was used in further analyses. Plasma availability of rutin was detected from 2h to at least 8h after ischemia. The treatment did not result in reduction of lesion volume but reduced the number of degenerated neurons at the periphery of the lesion. The results suggest rutin as an efficient drug to treat brain ischemia since it was able to promote significant recovery of sensorimotor loss, which was correlated to the reduction of neurodegeneration in the periphery of cortical injury. Increasing studies with rutin and other flavonoids might give support for further clinical trials with these drugs.

Antipyretic, analgesic and anti-oxidative activities of Aquilaria crassna leaves extract in rodents

In Thailand, the leaves of Aquilaria crassna have been used traditionally for the treatments of various disorders, but without any scientific analysis. In this study, the antipyretic, analgesic, anti-inflammatory and anti-oxidative properties of A. crassna leaves extract were investigated at a wide dose range in rodents. Experimental animals were treated orally with an aqueous extract of Aquilaria crassna leaves (ACE). They were tested for antipyretic (Baker's yeast-induced fever in rats), analgesic (hot plate test in mice) and anti-inflammatory (carrageenan-induced paw edema in rats) activities. An anti-oxidative effect of ACE was evaluated by using the DPPH anti-oxidant assay. The results showed that, after 5 hours of yeast injection, 400 and 800 mg/kg ACE significantly reduced the rectal temperature of rats. Mice were found significantly less sensitive to heat at an oral dose of 800 mg/kg ACE, after 60 and 90 min. No anti-inflammatory activity of ACE at an 800 mg/kg dose could be observed in the rat paw assay. An anti-oxidative activity of ACE was observed with an IC ₅₀value of 47.18 μg/ ml. No behavioral or movement change could be observed in mice after oral administration of ACE (800 or 8,000 mg/kg) for seven consecutive days. Interestingly, from the second day of treatment, animals had a significant lower body weight at the 8,000 mg/kg dose of ACE compared to the control. No toxicity was identified and the results of this study state clearly that Aquilaria crassna leaves extracts possess antipyretic, analgesic and anti-oxidative properties without anti-inflammatory activity.