Neurobehavioral aspects of antioxidants in aging

Chronological and Biological Aging in Amyotrophic Lateral Sclerosis and the Potential of Senolytic Therapies

Amyotrophic Lateral Sclerosis (ALS) is a group of sporadic and genetic neurodegenerative disorders that result in losses of upper and lower motor neurons. Treatment of ALS is limited, and survival is 2-5 years after disease onset. While ALS can occur in younger individuals, the risk significantly increases with advancing age. Notably, both sporadic and genetic forms of ALS share pathophysiological features overlapping hallmarks of aging including genome instability/DNA damage, mitochondrial dysfunction, inflammation, proteostasis, and cellular senescence. This review explores chronological and biological aging in the context of ALS onset and progression. Age-related muscle weakness and motor unit loss mirror aspects of ALS pathology and coincide with peak ALS incidence, suggesting a potential link between aging and disease development. Hallmarks of biological aging, including DNA damage, mitochondrial dysfunction, and cellular senescence, are implicated in both aging and ALS, offering insights into shared mechanisms underlying disease pathogenesis. Furthermore, senescence-associated secretory phenotype and senolytic treatments emerge as promising avenues for ALS intervention, with the potential to mitigate neuroinflammation and modify disease progression.

Edible Bird's Nest as a Potential Cognitive Enhancer

Cognitive enhancement is defined as the augmentation of the mind's core capabilities through the improvement of internal or external information processing systems. Recently, the focus has shifted to the potential therapeutic effects of natural products in improving cognitive function. Edible bird's nest (EBN) is a natural food substance derived from the saliva of swiftlets. Until today, EBN is regarded as a high-priced nutritious food with therapeutic effects. The effectiveness of dietary EBN supplementation to enhance brain development in mammals has been documented. Although the neuroprotection of EBN has been previously reported, however, the impact of EBN on learning and memory control and its potential as a cognitive enhancer drug remains unknown. Thus, this article aims to address the neuroprotective benefits of EBN and its potential effect as a cognitive enhancer. Notably, the current challenges and the future study direction in EBN have been demonstrated.

Addition of a blend of essential oils (cloves, rosemary and oregano) and vitamin E to replace conventional chemical antioxidants in dog feed: effects on food quality and health of beagles

This study aimed to produce dog food containing natural antioxidants (blend of essential oils and vitamin E) to replace synthetic antioxidants and determine the effects on food conservation and animal health sequentially. The foods were produced in a commercial factory, and the antioxidants were added at the oil bath stage. Ten adult beagle dogs were used, divided into two treatments; control treatment (CON; synthetic antioxidant feed [butylhydroxytoluene]) and test treatment (NAT; natural antioxidant feed; blend of essential oils from clove, rosemary, oregano, and vitamin E). The dogs were weighed at the beginning and end of each experimental period, and there were no treatment effects for body weight. In both treatments, food conservation efficiency was observed, demonstrating the feasibility of using natural sources as antioxidants in dog food because chemical and oxidative variables did not differ regardless of the antioxidant used during production. The animals' metabolic and haematological variables were not influenced by the treatments; however, a reduction in the number of lymphocytes was observed over time only in the dogs of the NAT group. There was also a day effect for total leukocyte, neutrophil and erythrocyte counts only in NAT animals, which means a significant increase (p ≤ 0.05) in the variables on d 28. There was an effect of the treatment and an interaction treatment x day for the total bacterial count, whereas a decrease in the bacterial count (p < 0.05) was observed in NAT dogs' faeces on day 28. Dogs fed the NAT diet had lower reactive oxygen species (ROS) (p ≤ 0.05) to minimise oxidative stress. In group NAT, the NPSH and glutathione S-transferase levels were increased, which may explain the decrease in ROS levels. It was concluded that natural antioxidants in dog feed, in addition to promoting feed conservation, stimulate levels of systemic antioxidants and minimise the impacts caused by free radicals in the dogs' blood.

Chalcones and Bis-Chalcones Analogs as DPPH and ABTS Radical Scavengers

Background:

A number of synthetic scaffolds, along with natural products, have been identified as potent antioxidants. The present study deals with the evaluation of varyingly substituted, medicinally distinct class of compounds “chalcones and bis-chalcones” for their antioxidant potential.

Methods:

In vitro radical scavenging activities were performed on a series of synthetic chalcones 1- 13 and bis-chalcones 14-18.

Results:

All molecules 1-18 revealed a pronounced 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2ʹ- azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals scavenging potential in the ranges of IC50s = 0.58 ± 0.14 - 1.72 ± 0.03 and 0.49 ± 0.3 - 1.48 ± 0.06 μM, respectively. Ascorbic acid (IC50s = 0.5 ± 0.1 and 0.46 ± 0.17 μM for DPPH and ABTS, respectively) was used as a standard radical scavenger.

Conclusion:

Structure-activity relationship (SAR) revealed an active participation of various groups, including -SMe and -OMe in scavenging activity.

Dynamic oxygen changes during status epilepticus and subsequent endogenous kindling

OBJECTIVE

Brain tissue oxygen (partial oxygen pressure [pO2 ]) levels are tightly regulated to stay within the normoxic zone, with deviations on either side resulting in impaired brain function. Whereas pathological events such as ischemic attacks and brief seizures have previously been shown to result in pO2 levels well below the normoxic zone, oxygen levels during prolonged status epilepticus (SE) and the subsequent endogenous kindling period are unknown.

METHODS

We utilized two models of acquired temporal lobe epilepsy in rats: intrahippocampal kainic acid infusion and prolonged perforant pathway stimulation. Local tissue oxygen was measured in the dorsal hippocampus using an optode during and for several weeks following SE.

RESULTS

We observed hyperoxia in the hippocampus during induced SE in both models. Following termination of SE, 88% of rats initiated focal self-generated spiking activity in the hippocampus within the first 7 days, which was associated with dynamic oxygen changes. Self-generated and recurring epileptiform activity subsequently organized into higher-frequency bursts that became progressively longer and were ultimately associated with behavioral seizures that became more severe with time and led to postictal hypoxia.

SIGNIFICANCE

Induced SE and self-generated recurrent epileptiform activity can have profound and opposing effects on brain tissue oxygenation that may serve as a biomarker for ongoing pathological activity in the brain.

Redox modifications in synaptic components as biomarkers of cognitive status, in brain aging and disease

Aging is a natural process that includes several changes that gradually make organisms degenerate and die. Harman's theory proposes that aging is a consequence of the progressive accumulation of oxidative modifications mediated by reactive oxygen/nitrogen species, which plays an essential role in the development and progression of many neurodegenerative diseases. This review will focus on how abnormal redox modifications induced by age impair the functionality of neuronal redox-sensitive proteins involved in axonal elongation and guidance, synaptic plasticity, and intercellular communication. We will discuss post-transcriptional regulation of gene expression by microRNAs as a mechanism that controls the neuronal redox state. Finally, we will discuss how some brain-permeant antioxidants from the diet have a beneficial effect on cognition. Taken together, the evidence revised here indicates that oxidative-driven modifications of specific proteins and changes in microRNA expression may be useful biomarkers for aging and neurodegenerative diseases. Also, some specific antioxidant therapies have undoubtedly beneficial neuroprotective effects when administered in the correct doses, in the ideal formulation combination, and during the appropriate therapeutic window. The use of some antioxidants is, therefore, still poorly explored for the treatment of neurodegenerative diseases such as Alzheimer's disease.

Protection of cholinergic and antioxidant system contributes to the effect of Vitamin D3 ameliorating memory dysfunction in sporadic dementia of Alzheimer's type

OBJECTIVE

Investigate Vitamin D3 (VD3) effect on the Acetylcholinesterase (AChE), oxidative damage and behavioral tests in animals subjected to Intracerebroventicular injection of Streptozotocin (ICV-STZ) simulating a Sporadic Dementia of Alzheimer's Type (SDAT) and treated with VD3 (21 days).

METHODS

Animals were divided into eight groups: Vehicle, VD12.5 μg/kg, VD42 μg/kg, VD125 μg/kg, STZ, STZ+VD12.5 μg/kg, STZ+VD42 μg/kg, STZ+VD125 μg/kg.

RESULTS

VD3 prevented the increase in AChE in groups of VD42 µg/kg and VD125 µg/kg; in AChE of synaptossomes and TBARS levels prevented the increase in group VD125 µg/kg; in ROS levels there was not a significant difference; for the Carbonyl Content all doses prevented the increase. Total Thiols prevent the decrease in VD42 µg/kg and VD125 µg/kg, and Reduced Glutathione prevented the decrease in VD125 µg/kg, Oxidized Glutathione prevented the increase in VD125 µg/kg. In relation to behavioral tests, the VD3 prevented the increase in time to find (days 2 and 3), in the time to find the platform (day 3) and in time spent in the quadrant (day 2). However, in relation to crossings there was not difference in groups. These results indicated the therapeutic effect of the VD3 in model of STZ in rats.

Hydrogen sulfide-mediated resistance against water avoidance stress-induced gastritis by maintenance of gastric microbial homeostasis

Chronic persistent stress is an important cause of gastritis, but the underlying mechanism remains to be further researched, especially the role of the gastric microbiota in this process. Here, we used the water avoidance stress (WAS) test in mouse models for chronic stress‐induced gastritis to investigate the underlying mechanisms of this disease. The effect of stress on the gastric microbiota was analyzed based on 16S rRNA sequencing; the changes in hydrogen sulfide (H₂S) and inflammatory cytokine levels in gastric tissues were detected by Western blotting, ELISA, immunofluorescence, and qRT‐PCR. Hematoxylin and eosin staining was used as an indicator of the gastritis histological score. This finding is consistent with previous studies showing that gastric H₂S is negatively associated with the inflammatory index and might protect the gastrointestinal tract from inflammation. WAS‐induced gastritis was associated with a reduction in H₂S release, which appeared to affect the homeostasis of the gastric microbiota of mice. Inflammation and microbial dysbiosis were partially reversed by sodium hydrosulfide (NaHS) and vitamin B6 (VB6) supplementation, suggesting the therapeutic potential of VB6 supplementation for the treatment of stress‐induced gastritis. Gastritis has a serious impact on health and quality of life. An increasing number of people are suffering from chronic gastritis linked to a high‐stress lifestyle, and our research provides clues for the prevention and treatment of stress‐induced gastritis.

Behavioral and molecular effects of intrahippocampal infusion of auraptene, resveratrol, and curcumin on H-89-induced deficits on spatial memory acquisition and retention in Morris water maze

Our aim was to investigate the effects of resveratrol, auraptene, and curcumin on the spatial learning and spatial memory retention in the Morris water maze (MWM). The effects of 4-day bilateral intrahippocampal (i.h.) infusions of dimethyl sulfoxide (DMSO), H-89 as a protein kinase AII inhibitor, auraptene/H-89, resveratrol/H-89, and curcumin/H-89 were investigated on spatial memory acquisition in MWM. The rats were trained for 4 days; each day included one block of four trials. Post-training probe tests were performed on day 5 in acquisition test. For retention assessments, different animals were trained for 4 days and then infused (i.h.) with either DMSO, H-89, auraptene/H-89, resveratrol/H-89, or curcumin/H-89. The retention test was performed 48 h after the last training trial. The bilateral infusion of H-89 led to a significant impairment in spatial memory in acquisition and retention tests accompanied with a significant decrease in expressions of cAMP response-element binding (CREB) and pCREB proteins in hippocampus. Resveratrol and curcumin reversed the H-89-induced spatial memory acquisition and retention impairments with significant increases in both CREB and pCREB proteins expressions compared to H-89-treated animals. Auraptene showed significant effects in reversing H-89-induced impairments in spatial memory retention but not spatial memory acquisition.

Effect of N-Acetyl Cysteine on Intracerebroventricular Colchicine Induced Cognitive Deficits, Beta Amyloid Pathology, and Glial Cells

Among the many factors responsible for the cognitive decline in Alzheimer's disease, beta amyloid protein and plaque formation is crucial. This amyloid pathology is associated with activation of glial cells and oxidative stress but whether oxidative stress activates beta amyloid protein in the neurons is not clear. Further the expression of microglia is also known to vary during pathogenesis of beta amyloid plaques. The aim of the present study is to evaluate the antioxidant effect of NAC on amyloid pathology and cognition and also to investigate the link between amyloid pathology and glial cells activation. Intracerebroventricular colchicine in rats known mimics human AD in many aspects including memory loss, oxidative stress, and hyper phosphorylation of tau protein. The animal groups consisted of age matched control, sham operated, AD, and NAC treated in AD models of rats. Cognitive function was evaluated in active avoidance test; beta amyloid protein, beta amyloid plaques, astrocytes, and microglia cells were quantified using immunohistochemistry in hippocampal and prefrontal cortices. Colchicine has resulted in significant cognitive loss, increased intraneuronal beta amyloid protein expression, increased reactive astrocytes, and activated microglia in all the regions of the hippocampus and prefrontal cortices. The antioxidant NAC has reversed the cognitive deficits and inhibited microglia activation but failed to inhibit BAP expression and astrocytosis. Intraneuronal BAP accumulation is deleterious and known to adversely affect cognition, but in this study in spite of intraneuronal BAP accumulation, the cognition is restored. It can be postulated that NAC might have reversed the effect of intraneuronal beta amyloid protein by acting on some downstream compensatory mechanisms which needs to be explored.

Effect of a Strawberry and Spinach Dietary Supplement on Spatial Learning in Early and Late Middle-Aged Female Rats

The present experiment sought to determine the effect of an eight-week, high antioxidant, whole-foods dietary supplement on Morris Water Maze performance in early and late middle-aged female rats. To improve ecological validity over past experimental studies, rats in the current study received antioxidants by consuming freeze-dried organic strawberries and spinach rather than by being given food extracts or antioxidant injections. Latency and path length measures both indicated that late middle-aged rats fed the high antioxidant diet performed on a par with the younger animals earlier in training than their standard diet counterparts (p < 0.05). Superior performance was not due to improved fitness in the antioxidant-supplemented rats. Thus, our model showed that a high antioxidant diet of relatively short duration mitigated the mild cognitive decline that was seen in control animals during the developmental period of late middle-age. The current results offer support for the promising role of dietary antioxidants in maintaining cognitive health in normal aging and extend past findings to females, who have been relatively neglected in experimental investigations. Moreover, the current model suggests that the period of transition from early to late middle age is a promising target for dietary intervention in healthy adults.

'Governor vessel-unblocking and mind-regulating' acupuncture therapy ameliorates cognitive dysfunction in a rat model of middle cerebral artery occlusion

Acupuncture is a traditional Chinese medicinal therapy, which is used for the amelioration of cognitive dysfunction. The aim of this study was to investigate the effectiveness and relevancy mechanisms of ‘governor vessel-unblocking and mind-regulating’ acupuncture therapy for cognitive dysfunction in rats with ischemia. For this purpose, we used the middle cerebral artery occlusion (MCAO) method to induce cognitive dysfunction in rats. The behavioral changes in the rats were examined using the Morris water maze (MWM) test. The effects of the treatment on oxidative stress response and the function of the mitochondria in brain tissues were also assessed. The results revealed that ‘governor vessel-unblocking and mind-regulating’ acupuncture therapy markedly improved the cognitive ability of the rats with cognitive dysfunction. The production of pro-oxidative stress factors, including nitric oxide (NO) and inducible nitric oxide synthase (iNOS), was also blocked along with the amelioration of cognitive function, while the production of adenosine triphosphate (ATP), superoxide dismutase (SOD) and cyclooxygenase (COX) was restored. At the molecular level, the accumulation of amyloid β (Aβ) in the mitochondria was suppressed by ‘governor vessel-unblocking and mind-regulating’ acupuncture therapy, which may be attributed to the inhibition of the function of translocase of outer mitochondrial membrane 40 (TOMM40) and translocase of inner mitochondrial membrane 17A (TIMM17A). On the whole, the findings of the present study confirm the effects of ‘governor vessel-unblocking and mind-regulating’ acupuncture therapy on cognitive dysfunction induced by brain ischemia in rats, and that the mechanisms underlying the effects of this treatment might be mediated through the inhibition of TOMM40 and TIMM17A synthesis, which can relieve mitochondrial dysfunction from the accumulation of Aβ.

Carnosine as an effective neuroprotector in brain pathology and potential neuromodulator in normal conditions

Carnosine (b-alanyl-L-histidine) is an endogenous dipeptide widely distributed in excitable tissues, such as muscle and neural tissues-though in minor concentrations in the latter. Multiple benefits have been attributed to carnosine: direct and indirect antioxidant effect, antiglycating, metal-chelating, chaperone and pH-buffering activity. Thus, carnosine turns out to be a multipotent protector against oxidative damage. However, the role of carnosine in the brain remains unclear. The key aspects concerning carnosine in the brain reviewed are as follows: its concentration and bioavailability, mechanisms of action in neuronal and glial cells, beneficial effects in human studies. Recent literature data and the results of our own research are summarized here. This review covers studies of carnosine effects on both in vitro and in vivo models of cerebral damage, such as neurodegenerative disorders and ischemic injuries and the data on its physiological actions on neuronal signaling and cerebral functions. Besides its antioxidant and homeostatic properties, new potential roles of carnosine in the brain are discussed.

N-Acetyl Cysteine Supplement Minimize Tau Expression and Neuronal Loss in Animal Model of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the accumulation of neurofibrillary tangles (NFT), deposition of beta amyloid plaques, and consequent neuronal loss in the brain tissue. Oxidative stress to the neurons is often attributed to AD, but its link to NFT and β-amyloid protein (BAP) still remains unclear. In an animal model of AD, we boosted the oxidative defense by N-Acetyl cysteine (NAC), a precursor of glutathione, a powerful antioxidant and free radical scavenger, to understand the link between oxidative stress and NFT. In mimicking AD, intracerebroventricular (ICV) colchicine, a microtubule disrupting agent also known to cause oxidative stress was administered to the rats. The animal groups consisted of an age-matched control, sham operated, AD, and NAC treated in AD models of rats. Cognitive function was evaluated in a passive avoidance test; neuronal degeneration was quantified using Nissl staining. NFT in the form of abnormal tau expression in different regions of the brain were evaluated through immunohistochemistry using rabbit anti-tau antibody. ICV has resulted in significant cognitive and neuronal loss in medial prefrontal cortex (MFC) and all the regions of the hippocampus. It has also resulted in increased accumulation of intraneuronal tau in the hippocampus and MFC. NAC treatment in AD model rats has reversed the cognitive loss and neuronal degeneration. The intraneuronal tau expression also minimized with NAC treatment in AD model rats. Thus, our findings suggest that an antioxidant supplement during the progression of AD is likely to prevent neuronal degeneration by minimizing the neurofibrillary degeneration in the form of tau accumulation.

Effect of Genistein on the Transgenic Drosophila Model of Parkinson's Disease

Parkinson's disease (PD) is the second-most common neurodegenerative disorder and is characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Oxidative stress has also been linked with the progression of PD, hence the involvement of a natural plant product could offer neuroprotection. The present study deals with the effect of genistein on the transgenic flies expressing normal human alpha synuclein panneurally. The PD flies were exposed to 10, 20, 30, and 40 µM of genistein (mixed in diet) for 24 days. A significant dose-dependent increase in the life span and delay in the loss of climbing ability were observed in the PD flies exposed to genistein (p < .05). A significant dose-dependent decrease in oxidative stress markers and increase in dopamine content were observed in PD flies exposed to genistein. However, the exposure of genistein did not inhibit the expression of α-synuclein in the brains of PD flies.

Comparison of three different extracts of Centella asiatica for anti-amnesic, antioxidant and anticholinergic activities: in vitro and in vivo study

Centella asiatica (CA) has been used by Ayurvedic medical practitioners in India for almost 3000 years. The neuropharmacological properties of CA and its constituents have been studied extensively. Anti-oxidant, free radical scavenging and cholinergic modulatory activities are the reported mechanisms of action for its efficacy in memory disorders. Its medicinal values are mainly attributed to the presence of several triterpenes, namely asiatic acid, madecassic acid, asiaticoside, and madecassoside. The present study was aimed to investigate the role of these triterpenes content in CA extract on the antioxidant, cholinesterase modulation and anti-amnesic properties. The fractions of CA extract enriched for (CAE-EF) and depleted/freed of (CAE-FF) triterpenes contents were compared with methanolic extract (CAE). Both in vitro and in vivo methods for evaluation of antioxidant and anticholinergic activities were used. In vitro, free radical scavenging assays (ABTS, DPPH, NO, NORAC, and ORAC) and cholinesterase (AChE and BuChE) inhibition assays were used. For evaluation of anti-amnesic effect, scopolamine induced amnesia in rats, as the acute model of memory loss was used. Following behavioural assessments (MWM, PA, EPM), biomarkers of oxidative stress (reduced GSH, MDA and SOD activity) and cholinesterase (AChE and BuChE) status were also estimated in cerebral cortex and hippocampus of rat brain. The methanolic extract (CAE) was found to perform best among all three fractions for in vitro free radical scavenging, cholinesterase inhibition, improvement of scopolamine-induced amnesia and also in vivo antioxidant effect and cholinesterase inhibitory activities. Interestingly triterpenes free fraction (CAE-FF) showed better antioxidant activity than triterpenes enriched fraction (CAE-EF) along with comparable anti-amnesic effect. This indicates that triterpenes are not solely responsible for antioxidant activity, cholinesterase inhibitory and anti-amnesic effect of CA.

Alteration in biochemical parameters in the brain of transgenic Drosophila melanogaster model of Parkinson's disease exposed to apigenin

BACKGROUND

Oxidative stress is one of the key components of the pathology of various neurodegenerative disorders. Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons owing to the aggregation of alpha-synuclein (αS) in the brain. A number of polyphenols have been reported to inhibit the αS aggregation resulting in the possible prevention of PD. The involvement of free radicals in mediating the neuronal death in PD has also been implicated.

METHODS

In the present study, the transgenic flies expressing human αS in the brain were exposed to 10 μM, 20 μM, 40 μM, and 80 μM of apigenin established in diet for 24 days.

RESULTS

The flies showed an increase in life span, glutathione, and dopamine content. The exposure of PD flies to various doses of apigenin also results in the reduction of glutathione-S-transferase activity, lipid peroxidation, monoamine oxidase, caspase-3, and caspase-9 activity in a dose-dependent manner.

CONCLUSION

The results of the present study reveal that apigenin is potent in increasing the life span, dopamine content, reduced the oxidative stress as well as apoptosis in transgenic Drosophila model of PD.

Examining the impact of grape consumption on brain metabolism and cognitive function in patients with mild decline in cognition: A double-blinded placebo controlled pilot study

BACKGROUND

Natural compounds in grapes such as resveratrol are known for their antioxidant and anti-inflammatory properties. Some studies have shown a potential role for grapes or wine in slowing cognitive decline and other effects of aging. However, well-controlled experimental data obtained in human subjects are still in need of further development. Here we aimed to systematically assess effects of grapes on regional cerebral metabolism.

METHODS

Ten subjects with mild decline in cognition (mean, 72.2±4.7years; 50% female) were included in this analysis. Participants were randomized into an active grape formulation arm or a placebo arm which consumed a formulation free of polyphenols for six months. Cognitive performance was measured through neuropsychological assessments performed at baseline and 6months after initiation of therapy. Changes in brain metabolism occurring with each therapy regimen were assessed by brain PET scans with the radiotracer [F-18] fluorodeoxyglucose (FDG), obtained during initial evaluation and 6months later. Standardized volumes of interest (sVOI) and statistical parametric mapping (SPM) methods were applied to FDG-PET scans to identify significant regional cerebral metabolic changes.

RESULTS

In contrast to participants taking the active grape formulation, who displayed no significant decline in metabolism, the placebo arm underwent significant metabolic decline in sVOI's of the right posterior cingulate cortex (p=0.01), and left superior posterolateral temporal cortex (p=0.04). SPM analyses also found significant declines in the placebo group, particularly in left prefrontal, cingulate, and left superior posterolateral temporal cortex (p<0.01) with stable brain metabolism in the active formulation arm. No significant differences were seen in scores on the neuropsychological battery of tests between the two groups. However, metabolism in right superior parietal cortex and left inferior anterior temporal cortex was correlated with improvements in attention/working memory, as measured with WAIS-III Digital Span within the active formulation group (r=-0.69, p=0.04).

CONCLUSIONS

The placebo arm had declines in regions of the brain known to be significantly affected in the early stages of Alzheimer's disease, while the active formulation group was spared such decline. This suggests a protective effect of grapes against early pathologic metabolic decline.

Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity

In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated.

Protective effects of resveratrol on aging-induced cognitive impairment in rats

Resveratrol, a polyphenol phytoalexine, has been shown to play a neuroprotective role in the neurodegenerative process in Alzheimer's disease (AD) and improve memory function in dementia. However, the in vivo effect of resveratrol in normal aging models of learning and memory has not yet been evaluated. Therefore, the present neurobehavioral study was undertaken to evaluate the effect of resveratrol on cognitive impairment induced by aging in passive avoidance and Morris water maze (MWM) tests. Male Wistar albino rats were divided into four groups: young control (4month), young resveratrol (4month+RESV), old control (24month) and old resveratrol (24month+RESV). Resveratrol (50mg/kg/day) was given to the 4month+RESV and 24month+RESV groups orally for 12weeks. There was no significant difference between the groups for the first day of latency, while in aged rats, the second day of latency was significantly shortened compared to the young group in the passive avoidance test (p<0.05). Additionally, in the MWM test, the results showed a decrease in the time spent in the escape platform's quadrant in the probe test in aged rats (p<0.05). The administration of resveratrol at 50mg/kg/day increased the retention scores in the passive avoidance test and the time spent in the escape platform's quadrant in the MWM task (p<0.05). Furthermore resveratrol attenuated the protein levels of TNFα and IL1β in the 24-month group. These findings indicate that aging impairs emotional and spatial learning-memory and resveratrol reverses the effect of age-related learning and memory impairment. The results of this study suggest that resveratrol is effective in preventing cognitive deficit in aged rats by inhibiting the production of inflammatory cytokines.

Are Polyphenols Strong Dietary Agents Against Neurotoxicity and Neurodegeneration?

Life expectancy of most human populations has greatly increased as a result of factors including better hygiene, medical practice, and nutrition. Unfortunately, as humans age, they become more prone to suffer from neurodegenerative diseases and neurotoxicity. Polyphenols can be cheaply and easily obtained as part of a healthy diet. They present a wide range of biological activities, many of which have relevance for human health. Compelling evidence has shown that dietary phytochemicals, particularly polyphenols, have properties that may suppress neuroinflammation and prevent toxic and degenerative effects in the brain. The mechanisms by which polyphenols exert their action are not fully understood, but it is clear that they have a direct effect through their antioxidant activities. They have also been shown to modulate intracellular signaling cascades, including the PI3K-Akt, MAPK, Nrf2, and MEK pathways. Polyphenols also interact with a range of neurotransmitters, illustrating that these compounds can promote their health benefits in the brain through a direct, indirect, or complex action. We discuss whether polyphenols obtained from diet or food supplements are an effective strategy to prevent or treat neurodegeneration. We also discuss the safety, mechanisms of action, and the current and future relevance of polyphenols in clinical treatment of neurodegenerative diseases. As populations age, it is important to discuss the dietary strategies to avoid or counteract the effects of incurable neurodegenerative disorders, which already represent an enormous financial and emotional burden for health care systems, patients, and their families.

Effect of Vitamin E Administration on Learning of the Young Male Rats

The effect of vitamin E intake on spatial learning and working memory performances of young rats has been investigated in the Morris water maze and locomotor activity has been assessed by an open-field test. A total of 45 young male Wistar albino rats aged two months were divided into three equal groups: control, olive oil, and vitamin E groups. These groups were treated for 30 days with a once daily intraperitoneal injection. The rats were then tested for their ability to find the location of the platform (spatial learning). The results revealed that there was no statistically significant difference between the time spent to find the platform and the time spent in half area of the tank, including the platform among the group, while the time spent to find the platform was found to have increased from the first day to the fourth day in all the groups. In the open-field test, the locomotor activity quite significantly increased in the peripheral area in the olive oil group. The supplementation with vitamin E for a short period had not improved the learning performance of the healthy young rats. It was concluded that the beneficial effect of vitamin E intake on learning is related to the beginning time and the duration of vitamin E intake.

Synthesis, molecular structure and electrochemical properties of nickel(ii) benzhydrazone complexes: influence of ligand substitution on DNA/protein interaction, antioxidant activity and cytotoxicity

Four new nickel(ii) benzhydrazone complexes were synthesized and characterized. The influence of ligand substitution on DNA/protein binding, antioxidant activity and cytotoxicity is described. The complexes are able to induce apoptosis in cancer cells.

Protective Effects of Crocus Sativus L. Extract and Crocin against Chronic-Stress Induced Oxidative Damage of Brain, Liver and Kidneys in Rats

PURPOSE

Chronic stress has been reported to induce oxidative damage of the brain. A few studies have shown that Crocus Sativus L., commonly known as saffron and its active constituent crocin may have a protective effect against oxidative stress. The present work was designed to study the protective effects of saffron extract and crocin on chronic - stress induced oxidative stress damage of the brain, liver and kidneys.

METHODS

Rats were injected with a daily dose of saffron extract (30 mg/kg, IP) or crocin (30 mg/kg, IP) during a period of 21 days following chronic restraint stress (6 h/day). In order to determine the changes of the oxidative stress parameters following chronic stress, the levels of the lipid peroxidation product, malondialdehyde (MDA), the total antioxidant reactivity (TAR), as well as antioxidant enzyme activities glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) were measured in the brain, liver and kidneys tissues after the end of chronic stress.

RESULTS

In the stressed animals that receiving of saline, levels of MDA, and the activities of GPx, GR, and SOD were significantly higher (P<0.0001) and the TAR capacity were significantly lower than those of the non-stressed animals (P<0.0001). Both saffron extract and crocin were able to reverse these changes in the stressed animals as compared with the control groups (P<0.05).

CONCLUSION

These observations indicate that saffron and its active constituent crocin can prevent chronic stress-induced oxidative stress damage of the brain, liver and kidneys and suggest that these substances may be useful against oxidative stress.

Reducing occupational stress with a B-vitamin focussed intervention: a randomized clinical trial: study protocol

Background

Workplace stress in Australia and other western countries has been steadily increasing over the past decade. It can be observed not only in terms of increased compensation claims but also costs due to absenteeism, loss of productivity at work and reduced psychological and physiological health and well-being. Given the cost and pervasive effects of stress in the modern workforce, time efficient and cost-effective interventions capable of reducing occupational stress (or strain) and burnout are urgently required for the improved well-being of stressed employees. One intervention gaining scientific traction is supplementation with nutritional interventions, particularly the B group vitamins.

Methods

This study was developed to examine the effects of B group vitamins on workplace stress and mood variables with a sample of full-time employed older adults who subjectively report feeling stressed. The study is a randomized, double-blind, placebo-controlled, parallel-groups clinical trial where 200 (N = 100/group) participants will be randomized to receive Blackmores® Executive B Stress Formula or placebo daily for a period of 6 months. Participants will be tested at baseline and 6 months post-randomization on workplace stress, cognitive, personality and mood measures, cardiovascular (brachial and aortic systolic and diastolic blood pressures as well as arterial stiffness), biochemical (assays to measure inflammation and safety) as well as genetic assessments (to assess stress processing) and neuroimaging measures (to investigate in vivo mechanisms of action of B vitamins). In addition to this pre- and post- supplementation testing, participants will also complete a battery of self-report questionnaires online to assess their stress and mood once a month for the duration of the study. The primary aim of the study is to investigate the effects of B vitamin supplementation on work related stress. The secondary aims are to explore the mechanisms underpinning any changes in mood or workplace stress due to the B vitamin intervention by examining relationships between cognitive, biological, neuroimaging and cardiovascular variables over 6 months. A subset of 40 participants (N = 20/group) will undergo neuroimaging at baseline and at 6 months using functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) in order to further explore in vivo mechanisms of action of B vitamins.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR):ACTRN12613000294752

Acupuncture improves cognitive function: A systematic review

BACKGROUND

Acupuncture has been used as a treatment for cognitive impairment.

OBJECTIVE

This review assesses clinical evidence for or against acupuncture as a treatment for cognitive impairment. This review also discusses the proposed mechanism(s) that could link acupuncture to improved cognitive function.

METHODS

We searched the literature using PolyUone search from its inception to January 2013, with full text available and language limited to English. Levels of evidence were examined using Oxford Centre for Evidence-based Medicine-Levels of Evidence (March, 2009).

RESULTS

TWELVE STUDIES MET THE INCLUSION CRITERIA: 3 human studies and 9 animal studies. Levels of evidence ranged from level 1b to level 5.

CONCLUSION

Most animal studies demonstrated a positive effect of acupuncture on cognitive impairment. However, the results of human studies were inconsistent. Further high-quality human studies with greater statistical power are needed to determine the effectiveness of acupuncture and an optimal protocol.

Introduction to biomedical literature text mining: context and objectives

If you are reading this, you know how important it is and almost certainly look to the biomedical literature for a large part of the information you need. We work hard to find more and more biomedical literature, seeking new content from multiple sources. But, can there be too much of a good thing? Most science is reductionist by nature. It is difficult enough finding the relevant nuggets of information from 1,000 documents. It is at least ten times harder to do so from 10,000 documents. And, with 25 million biomedical journal articles and many times that of other textual information sources, we are faced with significant challenges. In this introduction, we identify some of those challenges to prepare you for the remaining chapters.

Dietary intake of natural antioxidants: vitamins and polyphenols

Oxidative stress is a condition in which oxidant metabolites exert their toxic effect because of an increased production or an altered cellular mechanism of protection; oxidative stress is rapidly gaining recognition as a key phenomenon in chronic diseases. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. Endogenous defence mechanisms are inadequate for the complete prevention of oxidative damage, and different sources of dietary antioxidants may be especially important. This article calls attention to the dietary antioxidants, such as vitamins A, C, and E and polyphenols. Compelling evidence has led to the conclusion that diet is a key environmental factor and a potential tool for the control of chronic diseases. More specifically, fruits and vegetables have been shown to exert a protective effect. The high content of minerals and natural antioxidant as vitamins A, C, and E and polyphenols in fruits and vegetables may be a main factor responsible for these effects.

Anthocyanins in aged blueberry-fed rats are found centrally and may enhance memory

Research has shown that fruits and vegetables containing high levels of polyphenolics (flavonoids) display high total antioxidant activity. Our laboratory found that various fruit and vegetable extracts, particularly blueberry (BB), were effective in reversing age-related deficits in neuronal signaling and behavioral parameters following 8 weeks of feeding, possibly due to their polyphenolic content. However, it was unclear if these phytonutrients were able to directly access the brain from dietary BB supplementation (BBS). The present study examined whether different classes of polyphenols could be found in brain areas associated with cognitive performance following BBS. Thus, 19 month old F344 rats were fed a control or 2% BB diet for 8-10 weeks and tested in the Morris water maze (MWM), a measure of spatial learning and memory. LC-MS analyses of anthocyanins in the diet and subsequently in different brain regions of BBS and control rats were carried out. Several anthocyanins (cyanidin-3-O-beta-galactoside, cyanidin-3-O-beta-glucoside, cyanidin-3-O-beta-arabinose, malvidin-3-O-beta-galactoside, malvidin-3-O-beta-glucoside, malvidin-3-O-beta-arabinose, peonidin-3-O-beta-arabinose and delphinidin-3-O-beta-galactoside) were found in the cerebellum, cortex, hippocampus or striatum of the BBS rats, but not the controls. These findings are the first to suggest that polyphenolic compounds are able to cross the blood brain barrier and localize in various brain regions important for learning and memory. Correlational analyses revealed a relationship between MWM performance in BBS rats and the total number of anthocyanin compounds found in the cortex. These findings suggest that these compounds may deliver their antioxidant and signaling modifying capabilities centrally.

The effects of green Ocimum basilicum hydroalcoholic extract on retention and retrieval of memory in mice

The purpose of this study was evaluation of green Ocimum basilicum (sweet basil) hydroalcoholic extract on memory retention and retrieval of mice by using passive avoidance apparatus. For this purpose, after weighting, coding and classifying the mice, they were grouped (n = 8) as follow as: test groups (electric shock plus sweet basil extract by doses: 100, 200, 400 and 800 mg/kg, i.p.), control group (Only electric shock) and blank group (electric shock plus normal saline). In all mentioned groups delay time of leaving the platform for both retention and retrieval test of memory was measured. In retention test, sweet basil extract was administered immediately after receiving electric shock and in retrieval test it was administered 24 hours after receiving electric shock. The results indicated that hydroalcoholic extract of green Ocimum basilicum significantly (P < 0.05) increased memory retention. The best response was achieved with 400 mg/Kg of the extract. Also, results showed that sweet basil extract significantly (P < 0.05) increased memory retrieval and the best result was achieved with 400 mg/Kg too. It can be concluded that memory enhancing effects of green Ocimum basilicum is because of antioxidant activity of flavonoids, tannins and terpenoids.

Cognitive enhancement and neuroprotection by catechin-rich oil palm leaf extract supplement

BACKGROUND

Catechin-rich oil palm (Elaeis guineensis) leaf extract (OPLE) has good cardiovascular and phytoestrogenic properties. The OPLE (0.5 g day(-1) ) was supplemented to young, healthy, adult human volunteers, and their cognitive learning abilities were compared to placebo-controlled groups (N = 15). Their short-term memories, spatial visualisations, processing speeds, and language skills, were assessed over 2 months by cognitive tests computer programs.

RESULTS

Relative to the controls, volunteers taking OPLE had improved (P < 0.05) short-term memory, after 1 month of intervention which became highly significant (P < 0.005) after 2 months. The spatial visualisation ability and processing speed improved (P < 0.05) after 2 months consumption. The dietary OPLE showed neuroprotection in nitric oxide-deficient rats. The mechanisms involved systemic and cellular modulations that eventually enhance neuron survival. The longer the duration of OPLE consumption, the more significant was the enhancement, as shown for short-term memory.

CONCLUSION

This is the first report on the cognitive-enhancing effects of dietary OPLE in humans. The computer-assisted cognitive tests were simple, low in cost, errors and man hours, and hence are better than conventional cognitive test methods. In rats, the equivalent OPLE dose showed brain antioxidant enzymes modulating properties and neuroprotection under nitric oxide deficiency, with possibly neurogenesis in normal rats. This supported the effects in humans.

Updated knowledge about polyphenols: functions, bioavailability, metabolism, and health

Polyphenols are important constituents of food products of plant origin. Fruits, vegetables, and beverages are the main sources of phenolic compounds in the human diet. These compounds are directly related to sensory characteristics of foods such as flavor, astringency and color. Polyphenols are extensively metabolized both in tissues and by the colonic microbiota. Normally, the circulating polyphenols are glucuronidated and/or sulphated and no free aglycones are found in plasma. The presence of phenolic compounds in the diet is beneficial to health due to their antioxidant, anti-inflammatory, and vasodilating properties. The health effects of polyphenols depend on the amount consumed and their bioavailability. Moreover, polyphenols are able to kill or inhibit the growth of microorganisms such as bacteria, fungi, or protozoans. Some dietary polyphenols may have significant effects on the colonic flora providing a type of prebiotic effect. The anti-nutrient properties of polyphenols are also discussed in this paper. The antioxidant, anti-inflammatory, vasodilating, and prebiotic properties of polyphenols make them potential functional foods.

Transmission resonance Raman spectroscopy: experimental results versus theoretical model calculations

A laser spectroscopic technique is described that combines transmission and resonance-enhanced Raman inelastic scattering together with low laser power (< 30 mW) and good spatial resolution (< 200 μm) as operational features. The monitoring of the transmitted inelastic scattering provides an increased signal-to-noise ratio because the low fluorescence background and, on the other hand, the resonant character of the laser excitation, leads to enhanced analytical sensitivity. The spectroscopic technique was applied to investigate the carotenoid content (specifically the β-carotene concentration) of distinct samples that included fruits, reaching a detection limit of the order of hundreds of picograms in solid samples, which is below the level needed for typical food control analysis. Additional features of the present development are direct sampling, noninvasive character, and fast analysis that is not time consuming. From a theoretical point of view, a model for the Raman signal dependence on the sample thickness is also presented. Essentially, the model considers the sample to be homogeneous and describes the underlying physics using only three parameters: the Raman cross-section, the laser-radiation attenuation cross-section, and the Raman signal attenuation cross-section. The model was applied successfully to describe the sample-size dependence of the Raman signal in both β-carotene standards and carrot roots. The present technique could be useful for direct, fast, and nondestructive investigations in food quality control and analytical or physiological studies of animal and human tissues.