Protective effect of black tea extract against aluminium chloride-induced Alzheimer's disease in rats: A behavioural, biochemical and molecular approach

New bithiophene derivative attenuated Alzheimer's disease induced by aluminum in a rat model via antioxidant activity and restoration of neuronal and synaptic transmission

BACKGROUND

One of the hypotheses that leads to an increased incidence of Alzheimer's disease (AD) is the accumulation of aluminum in the brain's frontal cortex. The present study aimed to evaluate the therapeutic role of a novel bithiophene derivative at two doses against AlCl3-induced AD in a rat model.

METHODOLOGY

Adult male rats were divided into six groups, 18 rats each. Group 1: naïve animals, group 2: animals received a daily oral administration of bithiophene dissolved in DMSO (1 mg/kg) for 30 days every other day, groups 3-6: animals received a daily oral administration of AlCl3 (100 mg/kg/day) for 45 consecutive days. Groups 4 and 5 received an oral administration of low or high dose of the bithiophene (0.5 or 1 mg/kg, respectively). Group 6; Animals were treated with a daily oral dose of memantine (20 mg/kg) for 30 consecutive days.

MAIN FINDINGS

Al disturbed the antioxidant milieu, elevated the lipid peroxidation, and depleted the antioxidants. It also disturbed the synaptic neurotransmission by elevating the activities of acetylcholine esterase and monoamine oxidase resulting in the depletion of dopamine and serotonin and accumulation of glutamate and norepinephrine. Al also deteriorated the expression of genes involved in apoptosis and the production of amyloid-β plaques as well as phosphorylation of tau. The new bithiophene at the low dose reversed most of the previous deleterious effects of aluminum in the cerebral cortex and was in many instances superior to the reference drug; memantine.

CONCLUSION

Taking together, the bithiophene modulated the AD etiology through antioxidant activity, prevention of neuronal and synaptic loss, and probably mitigating the formation of amyloid-β plaques and phosphorylation of tau.

Effects of Phytochemicals from Fermented Food Sources in Alzheimer's Disease In Vivo Experimental Models: A Systematic Review

The socioeconomic burden of Alzheimer's Disease (AD) stems from its characteristic multifactorial etiology and, implicitly, the difficulties associated with its treatment. With the increase in life expectancy and health awareness, nutraceuticals and functional foods are filling in the gaps left by the limitation of classical medical treatment in chronic conditions associated with lifestyle factors, such as neurological disorders. Processes, such as fermentation that enhance food phytochemical content are garnering increased attention due to their functional and health-related properties. This systematic review aims to provide an overview of the evidence of phytochemicals from fermented food sources inducing therapeutic outcomes and cognitive benefits from in vivo experimental models of Alzheimer's Disease. The present systematic review was conducted in accordance with PRISMA guidelines. Searches were performed in the following databases: MEDLINE, Embase, Cochrane, Scopus, Google Scholar, and Science Citation Index Expanded (Web of Science) by two independent reviewers. Titles and abstracts yielded by the search were screened for eligibility against the inclusion criteria. The search strategy yielded 1899 titles, encompassing studies from 1948 to 2022. After the removal of duplicates, and screening of titles, abstracts, and full texts, thirty three studies obtained from the original search strategy and seven studies from references satisfied the inclusion criteria and were included in the present systematic review. Several studies have emphasized the potential of fermentation to yield small-molecule phytochemicals that are not present in raw products. When these phytochemicals are combined, their collective strength has demonstrated the ability to exceed the antioxidant, anti-inflammatory, and neuroprotective benefits of individual phytochemicals when given in their pure form. Among the various fermented foods that have been studied, soy isoflavones obtained through fermentation have shown the most substantial evidence of altering phytochemical content and improving outcomes in animal models of AD. While promising in initial results, other fermented foods and traditional medicines require more detailed research in order to establish their effectiveness and proper utilization. As is, many of the experimental designs lacked phytochemical analysis of the used fermented product or comparison with the non-fermented counterpart. This, coupled with proper reporting in animal studies, will significantly raise the quality of performed studies as well as the weight of obtained results.

Current Naturopathy to Combat Alzheimer's Disease

Neurodegeneration is the progressive loss of structure or function of neurons, which may ultimately involve cell death. The most common neurodegenerative disorder in the brain happens with Alzheimer's disease (AD), the most common cause of dementia. It ultimately leads to neuronal death, thereby impairing the normal functionality of the central or peripheral nervous system. The onset and prevalence of AD involve heterogeneous etiology, either in terms of genetic predisposition, neurometabolomic malfunctioning, or lifestyle. The worldwide relevancies are estimated to be over 45 million people. The rapid increase in AD has led to a concomitant increase in the research work directed towards discovering a lucrative cure for AD. The neuropathology of AD comprises the deficiency in the availability of neurotransmitters and important neurotrophic factors in the brain, extracellular betaamyloid plaque depositions, and intracellular neurofibrillary tangles of hyperphosphorylated tau protein. Current pharmaceutical interventions utilizing synthetic drugs have manifested resistance and toxicity problems. This has led to the quest for new pharmacotherapeutic candidates naturally prevalent in phytochemicals. This review aims to provide an elaborative description of promising Phyto component entities having activities against various potential AD targets. Therefore, naturopathy may combine with synthetic chemotherapeutics to longer the survival of the patients.

Can habitual tea drinking be an effective approach against age-related neurodegenerative cognitive disorders: A systematic review and meta-analysis of epidemiological evidence

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75-0.88) and 0.69 (95% CIs: 0.61-0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14-1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

Progress in the development of naturally derived active metabolites-based drugs: Potential therapeutics for Alzheimer's disease

Alzheimer's disease (AD) is an extensive age-associated neurodegenerative disorder. In spite of wide-ranging progress in understanding the AD pathology for the past 50 years, clinical trials based on the hypothesis of amyloid-beta (Aβ) have reserved worsening particularly at late-stage human trials. Consequently, very few old drugs are presently used for AD with inadequate clinical consequences and various side effects. We focus on widespread pharmacological and beneficial principles for existing as well as future drugs. Multitargeting approaches by means of general antioxidant and anti-inflammatory mechanisms allied with particular receptor and/or enzyme-mediated actions in neuroprotection and neurodegeneration. The plant kingdom comprises a vast range of species with an incredible diversity of bioactive metabolites with diverse chemical scaffolds. In recent times, an increasing body of facts recommended the use of phytochemicals to decelerate AD's onset and progression. The definitive goal of AD investigation is to avert the onset of neurodegeneration, thereby allowing successful aging devoid of cognitive decline. At this point, we discussed the neurological protective role of natural products and naturally derived therapeutic agents for AD from various natural polyphenolic compounds and medicinal plants. In conclusion, medicinal plants act as a chief source of different bioactive constituents.

Centella asiatica Alleviates AlCl3-induced Cognitive Impairment, Oxidative Stress, and Neurodegeneration by Modulating Cholinergic Activity and Oxidative Burden in Rat Brain

Aluminum (Al) is linked to the development of many neurological disorders such as Alzheimer's disease (AD), Parkinson's disease, and autism. Centella asiatica (CA) is a regenerating herb traditionally used to stimulate memory. This study was designed to assess the neuroprotective role of ethanolic extract of CA (CAE) in AlCl₃-induced neurological conditions in rats. Adult rats were chronically treated with AlCl₃ (100 mg/kg b.w./day) for 60 days to establish the dementia model, and co-administration of CAE was evaluated for its ability to attenuate the toxic effect of AlCl₃. CAE was given orally at a dose of 150 and 300 mg/kg b.w./day, for 60 days. The behavioral performances of rats were tested through Y-maze and open field tests. Lipid peroxidation, superoxide dismutase, and catalase activity were evaluated to measure oxidative stress; and acetylcholinesterase (AChE) activity was assessed to evaluate cholinergic dysfunction in the rat brain. H&E staining was used to assess structural abnormalities in the cortex and hippocampus. The result showed that AlCl₃ induces cognitive dysfunction (impaired learning and memory, anxiety, diminished locomotor activity), oxidative stress, cholinergic impairment, and histopathological alteration in the rat brain. Co-administration of CAE with AlCl₃ markedly protects the brain from AlCl₃-induced cognitive dysfunction, oxidative stress, AChE activity, and cytoarchitectural alterations. Furthermore, 15 days CAE treatment after 45 days AlCl₃ administration markedly ameliorates the AlCl₃-induced neurotoxicity indicating its potential for therapeutic use.

Are homeostatic mechanisms aiding the reconstitution of the T-cell pool during lymphopenia in humans?

A timely recovery of T-cell numbers following haematopoietic stem-cell transplantation (HSCT) is essential for preventing complications, such as increased risk of infection and disease relapse. In analogy to the occurrence of lymphopenia-induced proliferation in mice, T-cell dynamics in humans are thought to be homeostatically regulated in a cell density-dependent manner. The idea is that T cells divide faster and/or live longer when T-cell numbers are low, thereby helping the reconstitution of the T-cell pool. T-cell reconstitution after HSCT is, however, known to occur notoriously slowly. In fact, the evidence for the existence of homeostatic mechanisms in humans is quite ambiguous, since lymphopenia is often associated with infectious complications and immune activation, which confound the study of homeostatic regulation. This calls into question whether homeostatic mechanisms aid the reconstitution of the T-cell pool during lymphopenia in humans. Here we review the changes in T-cell dynamics in different situations of T-cell deficiency in humans, including the early development of the immune system after birth, healthy ageing, HIV infection, thymectomy and hematopoietic stem cell transplantation (HSCT). We discuss to what extent these changes in T-cell dynamics are a side-effect of increased immune activation during lymphopenia, and to what extent they truly reflect homeostatic mechanisms.

Hizikia fusiforme functional oil (HFFO) prevents neuroinflammation and memory deficits evoked by lipopolysaccharide/aluminum trichloride in zebrafish

Background

Oxidative stress, cholinergic deficiency, and neuroinflammation are hallmarks of most neurodegenerative disorders (NDs). Lipids play an important role in brain development and proper functioning. Marine-derived lipids have shown good memory-improving potentials, especially those from fish and microalgae. The cultivated macroalga Hizikia fusiforme is healthy food and shows benefits to memory, but the study is rare on the brain healthy value of its oil. Previously, we had reported that the Hizikia fusiforme functional oil (HFFO) contains arachidonic acid, 11,14,17-eicosatrienoic acid, phytol, and other molecules displaying in vitro acetylcholinesterase inhibitory and nitroxide scavenging activity; however, the in vivo effect remains unclear. In this study, we further investigated its potential effects against lipopolysaccharides (LPS)- or aluminum trichloride (AlCl3)-induced memory deficiency in zebrafish and its drug-related properties in silica.

Methods

We established memory deficit models in zebrafish by intraperitoneal (i.p.) injection of lipopolysaccharides (LPS) (75 ng) or aluminum trichloride (AlCl3) (21 μg), and assessed their behaviors in the T-maze test. The interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), acetylcholine (ACh), and malondialdehyde (MDA) levels were measured 24 h after the LPS/AlCl3 injection as markers of inflammation, cholinergic activity, and oxidative stress. Furthermore, the interaction of two main components, 11,14,17-eicosatrienoic acid and phytol, was investigated by molecular docking, with the important anti-inflammatory targets nuclear factor kappa B (NF-κB) and cyclooxygenase 2 (COX-2). Specifically, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness properties of HFFO were studied by ADMETlab.

Results

The results showed that HFFO reduced cognitive deficits in zebrafish T-maze induced by LPS/AlCl3. While the LPS/AlCl3 treatment increased MDA content, lowered ACh levels in the zebrafish brain, and elevated levels of central and peripheral proinflammatory cytokines, these effects were reversed by 100 mg/kg HFFO except for MDA. Moreover, 11,14,17-eicosatrienoic acid and phytol showed a good affinity with NF-κB, COX-2, and HFFO exhibited acceptable drug-likeness and ADMET profiles in general.

Conclusion

Collectively, this study's findings suggest HFFO as a potent neuroprotectant, potentially valuable for the prevention of memory impairment caused by cholinergic deficiency and neuroinflammation.

Assessment of the neuroprotective potential of d-cycloserine and l-serine in aluminum chloride-induced experimental models of Alzheimer’s disease: In vivo and in vitro studies

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain accompanied by synaptic dysfunction and neurodegeneration. No effective treatment has been found to slow the progression of the disease. Therapeutic studies using experimental animal models have therefore become very important. Therefore, this study aimed to investigate the possible neuroprotective effect of D-cycloserine and L-serine against aluminum chloride (AlCl₃)-induced AD in rats. Administration of AlCl₃ for 28 days caused oxidative stress and neurodegeneration compared to the control group. In addition, we found that aluminum decreases α-secretase activity while increasing β-secretase and γ-secretase activities by molecular genetic analysis. D-cycloserine and L-serine application resulted in an improvement in neurodegeneration and oxidative damage caused by aluminum toxicity. It is believed that the results of this study will contribute to the synthesis of new compounds with improved potential against AlCl₃-induced neurodegeneration, cognitive impairment, and drug development research.

Differential neuroprotective effect of curcuminoid formulations in aluminum chloride-induced Alzheimer's disease

Alzheimer's disease (AD) is a slowly progressive brain degenerative disorder which gradually impairs memory, thinking, and ability to perform easy routine tasks. This degenerative disorder mainly targets the elderly people and has imposed an endemic burden on society. Hence, there is a crucial need to investigate the efficacious herbal pharmacotherapies that can effectively mitigate and prevent the pathological hallmarks of AD. The current study aims to explore the potential efficacy of curcuminoid-rich extract (CRE) and its ternary complex (TC). Experimental rodents were administered with AlCl₃ (300 mg/kg) to induce AD and treated with rivastigmine, curcuminoid crude extract, CRE, and TC orally for three consecutive weeks. Neurobehavioral, biochemical, and histopathological studies were performed from the last week of the study period. The mRNA expression of different pathological biomarkers was estimated by RT-qPCR analysis. The results of the study suggested that CRE and TC significantly improved the behavioral, biochemical parameters and acetylcholinesterase inhibitory activity in treatment groups. Histological analysis was also carried out indicating that the neurodegenerative changes and neuronal loss were stabilized by CRE and TC supplementation. CRE and TC supplementation remarkably downregulated the interleukin-1α, tumor necrosis factor-α, interleukin-1β, acetylcholinesterase, and β-secretase pathological gene expression. Hence, it was concluded that CRE and TC may act as promising candidates in the prevention of AD via numerous underlying signaling pathways.

Clinical and Preclinical Studies of Fermented Foods and Their Effects on Alzheimer’s Disease

The focus on managing Alzheimer’s disease (AD) is shifting towards prevention through lifestyle modification instead of treatments since the currently available treatment options are only capable of providing symptomatic relief marginally and result in various side effects. Numerous studies have reported that the intake of fermented foods resulted in the successful management of AD. Food fermentation is a biochemical process where the microorganisms metabolize the constituents of raw food materials, giving vastly different organoleptic properties and additional nutritional value, and improved biosafety effects in the final products. The consumption of fermented foods is associated with a wide array of nutraceutical benefits, including anti-oxidative, anti-inflammatory, neuroprotective, anti-apoptotic, anti-cancer, anti-fungal, anti-bacterial, immunomodulatory, and hypocholesterolemic properties. Due to their promising health benefits, fermented food products have a great prospect for commercialization in the food industry. This paper reviews the memory and cognitive enhancement and neuroprotective potential of fermented food products on AD, the recently commercialized fermented food products in the health and food industries, and their limitations. The literature reviewed here demonstrates a growing demand for fermented food products as alternative therapeutic options for the prevention and management of AD.

Marine fungal metabolite butyrolactone I prevents cognitive deficits by relieving inflammation and intestinal microbiota imbalance on aluminum trichloride-injured zebrafish

Background

Mounting evidences indicate that oxidative stress, neuroinflammation, and dysregulation of gut microbiota are related to neurodegenerative disorders (NDs). Butyrolactone I (BTL-I), a marine fungal metabolite, was previously reported as an in vitro neuroprotectant and inflammation inhibitor. However, little is known regarding its in vivo effects, whereas zebrafish (Danio rerio) could be used as a convenient in vivo model of toxicology and central nervous system (CNS) diseases.

Methods

Here, we employed in vivo and in silico methods to investigate the anti-NDs potential of BTL-I. Specifically, we established a cognitive deficit model in zebrafish by intraperitoneal (i.p.) injection of aluminum trichloride (AlCl₃) (21 μg) and assessed their behaviors in the T-maze test. The proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) as well as acetylcholinesterase (AChE) activity or glutathione (GSH) levels were assayed 24 h after AlCl₃ injection. The intestinal flora variation of the zebrafish was investigated by 16S rDNA high-throughput analysis. The marine fungal metabolite, butyrolactone I (BTL-I), was used to modulate zebrafish cognitive deficits evoked by AlCl₃ and evaluated about its effects on the above inflammatory, cholinergic, oxidative stress, and gut floral indicators. Furthermore, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness properties of BTL-I were studied by the in silico tool ADMETlab.

Results

BTL-I dose-dependently ameliorated AlCl₃-induced cognitive deficits in zebrafish. While AlCl₃ treatment elevated the levels of central and peripheral proinflammatory cytokines, increased AChE activity, and lowered GSH in the brains of zebrafish, these effects, except GSH reduction, were reversed by 25–100 mg/kg BTL-I administration. Besides, 16S rDNA high-throughput sequencing of the intestinal flora of zebrafish showed that AlCl₃ decreased Gram-positive bacteria and increased proinflammatory Gram-negative bacteria, while BTL-I contributed to maintaining the predominance of beneficial Gram-positive bacteria. Moreover, the in silico analysis indicated that BTL-I exhibits acceptable drug-likeness and ADMET profiles.

Conclusions

The present findings suggest that BTL-I is a potential therapeutic agent for preventing CNS deficits caused by inflammation, neurotoxicity, and gut flora imbalance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02403-3.

Selected Natural Products in Neuroprotective Strategies for Alzheimer's Disease-A Non-Systematic Review

Neurodegenerative disorders such as Alzheimer’s disease (AD) are distinguished by the irreversible degeneration of central nervous system function and structure. AD is characterized by several different neuropathologies—among others, it interferes with neuropsychiatrical controls and cognitive functions. This disease is the number one neurodegenerative disorder; however, its treatment options are few and, unfortunately, ineffective. In the new strategies devised for AD prevention and treatment, the application of plant-based natural products is especially popular due to lesser side effects associated with their taking. Moreover, their neuroprotective activities target different pathological mechanisms. The current review presents the anti-AD properties of several natural plant substances. The paper throws light on products under in vitro and in vivo trials and compiles information on their mechanism of actions. Knowledge of the properties of such plant compounds and their combinations will surely lead to discovering new potent medicines for the treatment of AD with lesser side effects than the currently available pharmacological proceedings.

Developmental alterations, teratogenic effects, and oxidative disruption induced by ibuprofen, aluminum, and their binary mixture on Danio rerio

Several studies highlighted the ubiquitous presence of ibuprofen and aluminum in the aquatic environment around the world and demonstrated their potential to induce embryotoxic and teratogenic defects on aquatic species individually. Although studies that evaluate developmental alterations induced by mixtures of these pollutants are scarce; and, since environmental contamination presented in the form of a mixture of toxicants with different chemical properties and toxicity mechanisms capable of generating interactions; the objective of this study was to evaluate the developmental defects, teratogenic alterations, and oxidative stress induced by individual forms and the mixture of ibuprofen (IBU) and aluminum (Al) on zebrafish embryos. Oocytes exposed to environmentally relevant concentrations of IBU (0.1-20 μg L-1) and Al (0.01-8 mg L-1) and one binary mixture. The LC50 and EC50 were obtained to calculate the teratogenic index (TI). The IBU LC50, EC50, and TI were 8.06 μg L-1, 2.85 μg L-1 and 2.82. In contrast, Al LC50 was 5.0 mg L-1with an EC50 of 3.58 mg L-1 and TI of 1.39. The main alterations observed for individual compounds were hatching alterations, head malformation, skeletal deformities, hypopigmentation, pericardial edema, and heart rate impairment. The mixture also showed significant delays to embryonic development. Moreover, oxidative stress biomarkers of cellular oxidation and antioxidant defenses at 72 and 96 hpf significantly increased. Results show that environmentally relevant concentrations of ibuprofen (IBU), aluminum (Al), and their mixture promote a series of developmental defects, teratogenic effects, and oxidative disruption on D. rerio embryos, and the interaction of both substances altered the response. In conclusion, morphological and biochemical tests are suitable tools for assessing the health risk of aquatic wildlife by exposure to individual and mixed pollutants in freshwater bodies.

Powdered Green Tea (Matcha) Attenuates the Cognitive Dysfunction via the Regulation of Systemic Inflammation in Chronic PM2.5-Exposed BALB/c Mice

This study was conducted to evaluate the anti-amnesic effect of the aqueous extract of powdered green tea (matcha) (EM) in particulate matter (PM)_2.5-induced systemic inflammation in BALB/c mice. EM ameliorated spatial learning and memory function, short-term memory function, and long-term learning and memory function in PM_2.5-induced mice. EM protected against antioxidant deficit in pulmonary, dermal, and cerebral tissues. In addition, EM improved the cholinergic system through the regulation of acetylcholine (ACh) levels and acetylcholinesterase (AChE) activity in brain tissue, and it protected mitochondrial dysfunction by regulating the production of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and ATP contents in brain tissue. EM attenuated systemic inflammation and apoptotic signaling in pulmonary, dermal, olfactory bulb, and hippocampal tissues. Moreover, EM suppressed neuronal cytotoxicity and cholinergic dysfunction in hippocampal tissue. This study suggests that EM might be a potential substance to improve PM_2.5-induced cognitive dysfunction via the regulation of systemic inflammation.

Potential of Sorghum Polyphenols to Prevent and Treat Alzheimer's Disease: A Review Article

Alzheimer's disease (AD) is characterized by the excessive deposition of extracellular amyloid-beta peptide (Aβ) and the build-up of intracellular neurofibrillary tangles containing hyperphosphorylated tau proteins. This leads to neuronal damage, cell death and consequently results in memory and learning impairments leading to dementia. Although the exact cause of AD is not yet clear, numerous studies indicate that oxidative stress, inflammation, and mitochondrial dysfunction significantly contribute to its onset and progression. There is no effective therapeutic approach to stop the progression of AD and its associated symptoms. Thus, early intervention, preferably, pre-clinically when the brain is not significantly affected, is a better option for effective treatment. Natural polyphenols (PP) target multiple AD-related pathways such as protecting the brain from Aβ and tau neurotoxicity, ameliorating oxidative damage and mitochondrial dysfunction. Among natural products, the cereal crop sorghum has some unique features. It is one of the major global grain crops but in the developed world, it is primarily used as feed for farm animals. A broad range of PP, including phenolic acids, flavonoids, and condensed tannins are present in sorghum grain including some classes such as proanthocyanidins that are rarely found in others plants. Pigmented varieties of sorghum have the highest polyphenolic content and antioxidant activity which potentially makes their consumption beneficial for human health through different pathways such as oxidative stress reduction and thus the prevention and treatment of neurodegenerative diseases. This review summarizes the potential of sorghum PP to beneficially affect the neuropathology of AD.

Long-term exposure to environmentally relevant concentrations of ibuprofen and aluminum alters oxidative stress status on Danio rerio

Despite the ubiquitous presence of multiple pollutants in aqueous environments have been extensively demonstrated, the ecological impact of chemical cocktails has not been studied in depth. In recent years, environmental studies have mainly focused on the risk assessment of individual chemical substances neglecting the effects of complex mixtures even though it has been demonstrated that combined effects exerted by pollutants might represent a greater hazard to the biocenosis. The current study evaluates the effects on the oxidative stress status induced by individual forms and binary mixtures of ibuprofen (IBU) and aluminum (Al) on brain, gills, liver and gut tissues of Danio rerio after long-term exposure to environmentally relevant concentrations (0.1-11 μg L^-1 and 0.05 mg L^-1- 6 mg L^-1, respectively). Lipid peroxidation (LPO), Protein carbonyl content (PCC) and activity of Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPX) were evaluated. Moreover, concentrations of both toxicants and the metabolite 2-OH-IBU were quantified on test water and tissues. Results show that ibuprofen (IBU) and aluminum (Al) singly promote the production of radical species and alters the oxidative stress status in all evaluated tissues of zebrafish, nevertheless, higher effects were elicited by mixtures as different interactions take place.

Curcumin Attenuated Neurotoxicity in Sporadic Animal Model of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases leading to dementia. Despite research efforts, currently there are no effective pharmacotherapeutic options for the prevention and treatment of AD. Recently, numerous studies highlighted the beneficial effects of curcumin (CUR), a natural polyphenol, in the neuroprotection. Especially, its dual antioxidant and anti-inflammatory properties attracted the interest of researchers. In fact, besides its antioxidant and anti-inflammatory properties, this biomolecule is not degraded in the intestinal tract. Additionally, CUR is able to cross the blood-brain barrier and could therefore to be used to treat neurodegenerative pathologies associated with oxidative stress, inflammation and apoptosis. The present study aimed to assess the ability of CUR to induce neuronal protective and/or recovery effects on a rat model of neurotoxicity induced by aluminum chloride (AlCl3), which mimics the sporadic form of Alzheimer's disease. Our results showed that treatment with CUR enhances pro-oxidant levels, antioxidant enzymes activities and anti-inflammatory cytokine production and decreases apoptotic cells in AlCl3-exposed hippocampus rats. Additionally, histopathological analysis of hippocampus revealed the potential of CUR in decreasing the hallmarks in the AlCl3-induced AD. We also showed that CUR post-treatment significantly improved the behavioral, oxidative stress and inflammation in AlCl3-exposed rats. Taken together, our data presented CUR as a nutraceutical potential through its protective effects that are more interesting than recovery ones in sporadic model of AD.

Dietary phytochemicals that influence gut microbiota: Roles and actions as anti-Alzheimer agents

The last decide has witnessed a growing research interest in the role of dietary phytochemicals in influencing the gut microbiota. On the other hand, recent evidence reveals that dietary phytochemicals exhibit properties of preventing and tackling symptoms of Alzheimer's disease, which is a neurodegenerative disease that has also been linked with the status of the gut microbiota over the last decade. Till now, little serious discussions, however, have been made to link recent understanding of Alzheimer's disease, dietary phytochemicals and the gut microbiota together and to review the roles played by phytochemicals in gut dysbiosis induced pathologies of Alzheimer's disease. Deciphering these connections can provide insights into the development and future use of dietary phytochemicals as anti-Alzheimer drug candidates. This review aims at presenting latest evidence in the modulating role of phytochemicals in the gut microbiota and its relevance to Alzheimer's disease and summarizing the mechanisms behind the modulative activities. Limitations of current research in this field and potential directions will also be discussed for future research on dietary phytochemicals as anti-Alzheimer agents.

Neuroprotective Effects of Higenamine Against the Alzheimer's Disease Via Amelioration of Cognitive Impairment, A Burden, Apoptosis and Regulation of Akt/GSK3β Signaling Pathway

The present investigation was envisaged to elucidate the neuroprotective effect of Higenamine (HGN) against aluminum chloride (AlCl₃) triggered experimental Alzheimer's disease (AD) rat model. Thirty-six male albino Wister rats were randomized and divided in 6 groups and subjected to experimentation for 6 weeks. Control group, AlCl₃ (100 mg/kg orally), HGN (50 mg/kg orally), HGN25, HGN50, HGN75 (HGN 25, 50 and 75 mg/kg respectively and AlCl₃ 100 mg/kg orally). After completion of 42 days protocol, the animals were subjected to passive avoidance test. The animals were then anesthetized by intramuscularly injecting ketamine hydrochloride (24 mg/kg body weight) and euthanized by cervical amputation. Cortical and hippocampal tissues were carefully removed and were employed for quantification of aluminum and acetylcholinesterase. The tissues were quantified using Western blotting and detection kits for APP, Aβ_1-42, β and γ secretases, Bax, Bad, caspases-9, cyto-c, pAkt and pGSK-3β, and oxidative markers. HGN significantly protected AlCl₃ induced memory and learning impairments, Al overload, AChE hyperactivity, amyloid β (Aβ) burden and apoptosis in brain tissues via activating Akt/GSK3β pathway. HGN attenuated oxidative damage induced by Al by modulation of oxidative markers. Our findings advocate the neuroprotective effect of HGN in AlCl₃ induced AD rat model.

Inhibitory potentials of Cymbopogon citratus oil against aluminium-induced behavioral deficits and neuropathology in rats

Cymbopogon citratus is a tropical phytomedicinal plant that is widely known for its hypoglycemic, hypolipidemic, anxiolytic, sedative, antioxidative and anti-inflammatory properties. In this study, we have examined the neuroprotective effects of the essential oil (ESO) of Cymbopogon citratus, following aluminum chloride (AlCl₃)-induced neurotoxicity within the cerebellum of Wistar rats. A total of 40 adult male Wistar rats were assigned into five groups and treated orally as follows: A–phosphate-buffered saline (1 ml daily for 15 days); B–ESO (50 mg/kg daily for 15 days); C–AlCl₃ (100 mg/kg daily for 15 days); D–AlCl₃ then ESO (100 mg/kg AlCl₃ daily for 15 days followed by 50 mg/kg ESO daily for subsequent 15 days); E–ESO then AlCl₃ (50 mg/kg ESO daily for 15 days followed by 100 mg/kg AlCl₃ daily for following 15 days). To address our questions, we observed the locomotion and exploratory behavior of the rats in the open field apparatus and subsequently evaluated cerebellar oxidative redox parameters, neural bioenergetics, acetylcholinesterase levels, transferrin receptor protein, and total protein profiles by biochemical assays. Furthermore, we investigated cerebellar histomorphology and Nissl profile by H&E and Cresyl violet Nissl staining procedures. ESO treatment markedly attenuated deficits in exploratory activities and rearing behavior following AlCl₃ toxicity, indicating its anxiolytic potentials. Additionally, AlCl₃ evokedincrease in malondialdehyde and nitric oxide levels, as well as repressed cerebellar catalase, glutathione peroxidase, and superoxide dismutase profiles were normalised to baseline levels by ESO treatment. Treatment with ESO, ergo, exhibits substantial neuroprotective and modulatory potentials in response to AlCl₃ toxicity.

The Possible Neuroprotective Effect of Silymarin against Aluminum Chloride-Prompted Alzheimer's-Like Disease in Rats

Alzheimer's disease (AD) is a worldwide rapidly growing neurodegenerative disease. Here, we elucidated the neuroprotective effects of silymarin (SM) on the hippocampal tissues of aluminum chloride (AlCl3)-induced Alzheimer-like disease in rats using biochemical, histological, and ultrastructural approaches. Forty rats were divided into control, SM, AlCl3, and AlCl3 + SM groups. Biochemically, AlCl3 administration resulted in marked elevation in levels of lipid peroxidation (LPO) and nitric oxide (NO) and decrease in levels of reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). Moreover, AlCl3 significantly increased tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), and acetylcholinesterase (AChE) activities. Furthermore, myriad histological and ultrastructural alterations were recorded in the hippocampal tissues of AlCl3-treated rats represented as marked degenerative changes of pyramidal neurons, astrocytes, and oligodendrocytes. Additionally, some myelinated nerve fibers exhibited irregular arrangement of their myelin coats, while the others revealed focal degranulation of their myelin sheaths. Severe defects in the blood-brain barrier (BBB) were also recorded. However, co-administration of SM with AlCl3 reversed most of the biochemical, histological, and ultrastructural changes triggered by AlCl3 in rats. The results of the current study indicate that SM can potentially mend most of the previously evoked neuronal damage in the hippocampal tissues of AlCl3-kindled rats.

Health Functions and Related Molecular Mechanisms of Tea Components: An Update Review

Tea is widely consumed all over the world. Generally, tea is divided into six categories: White, green, yellow, oolong, black, and dark teas, based on the fermentation degree. Tea contains abundant phytochemicals, such as polyphenols, pigments, polysaccharides, alkaloids, free amino acids, and saponins. However, the bioavailability of tea phytochemicals is relatively low. Thus, some novel technologies like nanotechnology have been developed to improve the bioavailability of tea bioactive components and consequently enhance the bioactivity. So far, many studies have demonstrated that tea shows various health functions, such as antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, anti-obesity, and hepato-protective effects. Moreover, it is also considered that drinking tea is safe to humans, since reports about the severe adverse effects of tea consumption are rare. In order to provide a better understanding of tea and its health potential, this review summarizes and discusses recent literature on the bioactive components, bioavailability, health functions, and safety issues of tea, with special attention paid to the related molecular mechanisms of tea health functions.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Amelioration of Aluminium Chloride (AlCl3) Induced Neurotoxicity by Combination of Rivastigmine and Memantine with Artesunate in Albino Wistar Rats

Alzheimer’s disease (AD) is an age-related progressive disorder characterized by neurodegeneration and accumulation of abnormal proteins. Artesunate, an anti-malarial drug has recently been shown to have anti-inflammatory, antiviral, angiogenic and other pleiotropic effects. It has also improved cognitive decline induced by hepatic coma which is suggestive of its role in learning and memory. In view of this, the current study was planned to assess the effect of the combination of artesunate with rivastigmine and memantine in aluminium chloride induced neurotoxicity. The study was conducted on 24 male adult albino wistar rats which were divided into four groups (n=6). Group - I to IV received saline, aluminium chloride (AlCl3), AlCl3 + artesunate +rivastigmine, AlCl3 + artesunate + memantine for 60 days respectively. After the 60th day of treatment, all animals were subjected to a passive avoidance task. All the animals were then sacrificed to study the histopathological changes in the hippocampus. Artesunate in combination with rivastigmine and memantine showed significant improvement in memory impairment and reduced neuronal death. Neuronal viability was more prominent in combination treatments as shown by histopathological results. Artesunate in combination with rivastigmine and memantine could be useful in AD. Artesunate can be used as an adjuvant therapy because artesunate combined with standard drugs produced significant neuroprotective effect.

Centella asiatica Protects d-Galactose/AlCl3 Mediated Alzheimer's Disease-Like Rats via PP2A/GSK-3β Signaling Pathway in Their Hippocampus

Alzheimer's disease (AD) is a progressive neurodegenerative disorder more prevalent among the elderly population. AD is characterised clinically by a progressive decline in cognitive functions and pathologically by the presence of neurofibrillary tangles (NFTs), deposition of beta-amyloid (Aβ) plaque and synaptic dysfunction in the brain. Centella asiatica (CA) is a valuable herb being used widely in African, Ayurvedic, and Chinese traditional medicine to reverse cognitive impairment and to enhance cognitive functions. This study aimed to evaluate the effectiveness of CA in preventing d-galactose/aluminium chloride (d-gal/AlCl3) induced AD-like pathologies and the underlying mechanisms of action were further investigated for the first time. Results showed that co-administration of CA to d-gal/AlCl3 induced AD-like rat models significantly increased the levels of protein phosphatase 2 (PP2A) and decreased the levels of glycogen synthase kinase-3 beta (GSK-3β). It was further observed that, CA increased the expression of mRNA of Bcl-2, while there was minimal effect on the expression of caspase 3 mRNA. The results also showed that, CA prevented morphological aberrations in the connus ammonis 3 (CA 3) sub-region of the rat's hippocampus. The results clearly demonstrated for the first time that CA could alleviate d-gal/AlCl3 induced AD-like pathologies in rats via inhibition of hyperphosphorylated tau (P-tau) bio-synthetic proteins, anti-apoptosis and maintenance of cytoarchitecture.

Protective Effects of Centella asiatica on Cognitive Deficits Induced by D-gal/AlCl₃ via Inhibition of Oxidative Stress and Attenuation of Acetylcholinesterase Level

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with cholinergic dysfunctions and impaired redox homeostasis. The plant Centella asiatica (CA) is renowned for its nutritional benefits and herbal formulas for promoting health, enhancing cognition, and its neuroprotective effects. The present study aims to investigate the protective role of CA on D-gal/AlCl₃-induced cognitive deficits in rats. The rats were divided into six groups and administered with donepezil 1 mg/kg/day, CA (200, 400, and 800 mg/kg/day) and D-gal 60 mg/kg/day + AlCl₃ 200 mg/kg/day for 10 weeks. The ethology of the rats was evaluated by the Morris water maze test. The levels of acetylcholinesterase (AChE), phosphorylated tau (P-tau), malondialdehyde (MDA) and activities of superoxide dismutase (SOD), in the hippocampus and cerebral cortex were estimated by enzyme-linked immunosorbent assay (ELISA). Additionally, the ultrastructure of the prefrontal cortex of the rats’ was observed using transmission electron microscopy (TEM). Rats administered with D-gal/AlCl₃ exhibited cognitive deficits, decreased activities of SOD, and marked increase in AChE and MDA levels. Further, prominent alterations in the ultrastructure of the prefrontal cortex were observed. Conversely, co-administration of CA with D-gal/AlCl₃ improved cognitive impairment, decreased AChE levels, attenuated the oxidative stress in hippocampus and cerebral cortex, and prevented ultrastructural alteration of neurons in the prefrontal cortex. Irrespective of the dose of CA administered, the protective effects were comparable to donepezil. In conclusion, this study suggests that CA attenuated the cognitive deficits in rats by restoring cholinergic function, attenuating oxidative stress, and preventing the morphological aberrations.

Asiatic Acid Attenuated Aluminum Chloride-Induced Tau Pathology, Oxidative Stress and Apoptosis Via AKT/GSK-3β Signaling Pathway in Wistar Rats

Asiatic acid (AA), a triterpenoid present in Centella asiatica, possesses the ability to cross blood brain barrier and received considerable attention for its neuroprotective role. We have reported the benefit of AA against aluminum chloride (AlCl₃)-induced amyloid pathology, enhanced acetylcholine esterase (AChE) activity, and inflammation in Alzheimer's disease (AD) like model rats. Based on that, to find the exact mechanism of action of AA, the present study was designed to evaluate the oxidative stress, tau pathology, apoptosis, and Akt/GSK3β signaling pathway on AlCl₃-induced neurotoxicity in Wistar rats. AD-like pathology was induced by oral administration of AlCl₃ (100 mg/kg b.w.) for 6 weeks, which demonstrated a significant reduction in spatial memory performance, anxiety, and motor dysfunction and diminished the expression of cyclin-dependent kinase 5 (CDK 5-enzyme implicated in the phosphorylation of tau proteins), pTau, oxidative stress, and apoptosis, whereas oral ingestion of AA (75 mg/kg b.w.) for 7 weeks attenuated the above-said indices, which could be by activating Akt/GSK3β pathway. Current results suggested that AA could be able to modulate various pathological features of AD and could hold promise in AD treatment.

New rhodamine B-based chromo-fluorogenic probes for highly selective detection of aluminium(iii) ions and their application in living cell imaging

Two rhodamine B-based fluorescent probes, BOS1 and BOS2, were designed and synthesized with good yields via the condensation reactions between the o-diaminobenzene modified rhodamine core structure (RBO) and salicylaldehyde derivatives. Both the probes exhibited remarkable absorbance-on and fluorescence-on responses to Al³⁺ over other metal ions in ethanol–water (1 : 9, v/v) medium via the rhodamine ring-opening approach, which can be used for “naked-eye” Al³⁺ detection over a broad pH range (5–9). The fluorescence intensities of the probes were linear with the Al³⁺ ion concentration, resulting in a low limit of detection of 1.839 μM (BOS1) and 1.374 μM (BOS2) for Al³⁺. In addition, the MTT assays and cell imaging experiments of Al³⁺ in SGC-7901 living cells demonstrated that the probes had negligible cytotoxicity, and were cell permeable and suitable for sensing Al³⁺ in biological systems.

Two rhodamine B-based fluorescent probes exhibited remarkable absorbance-on and fluorescence-on responses to Al³⁺, which can be used for biological imaging.

Ameliorative and protective effects of ginger and its main constituents against natural, chemical and radiation-induced toxicities: A comprehensive review

Fatal unintentional poisoning is widespread upon human exposure to toxic agents such as pesticides, heavy metals, environmental pollutants, bacterial and fungal toxins or even some medications and cosmetic products. In this regards, the application of the natural dietary agents as antidotes has engrossed a substantial attention. One of the ancient known traditional medicines and spices with an arsenal of metabolites of several reported health benefits is ginger. This extended literature review serves to demonstrate the protective effects and mechanisms of ginger and its phytochemicals against natural, chemical and radiation-induced toxicities. Collected data obtained from the in-vivo and in-vitro experimental studies in this overview detail the designation of the protective effects to ginger's antioxidant, anti-inflammatory, and anti-apoptotic properties. Ginger's armoury of phytochemicals exerted its protective function via different mechanisms and cell signalling pathways, including Nrf2/ARE, MAPK, NF-ƙB, Wnt/β-catenin, TGF-β1/Smad3, and ERK/CREB. The outcomes of this review could encourage further clinical trials of ginger applications in radiotherapy and chemotherapy regime for cancer treatments or its implementation to counteract the chemical toxicity induced by industrial pollutants, alcohol, smoking or administered drugs.

Acute aluminum chloride toxicity revisited: Study on DNA damage and histopathological, biochemical and neurochemical alterations in rat brain

AIMS

Due to rapid increase in industrialization in the last few years, use of aluminum (Al) and its alloys have been increased in different industrial fields. Ample evidence supports the neurotoxic effects of chronic aluminum chloride (AlCl₃) administration in rats but acute Al toxicity has been less described so the present study was aimed to investigate the neurotoxic effects of acute AlCl₃.

MAIN METHODS

To investigate such effects 12 male albino Wistar rats were randomly divided into control and test rats. AlCl₃ at a dose of 150 mg/kg was intraperitoneally injected to test rats for 7 days. Rats were subjected to behavioral assessments 24 h after last dose and after behavioral assessment rats were sacrificed to collect brain samples for further neurochemical, biochemical and histopathological examinations.

KEY FINDINGS

In the present study acute administration of AlCl₃ resulted in noticeable behavioral deficits. Cognitive deficits and neuropsychiatric disturbances were evident in AlCl₃ injected rats. Test rats also exhibited marked antioxidant enzymes, cholinergic, serotonergic and dopaminergic dysfunctions and DNA fragmentation. Histopathological alterations were observed in hippocampus and cortex of rats injected with AlCl₃.

SIGNIFICANCE

The observed effects may be due to pro-oxidant nature of Al and its participation in free radical mediated cellular injury. Al by promoting oxidative stress, impairing antioxidant defense system and altering brain neurochemistry may act as a potent neurotoxic agent as evident from observed histopathological alterations in brain of test rats. This investigation may further confirm and shed some more light on deleterious effects of acute Al intoxication on brain.

Amelioration of Aluminum Maltolate-Induced Inflammation and Endoplasmic Reticulum Stress-Mediated Apoptosis by Tannoid Principles of Emblica officinalis in Neuronal Cellular Model

The neuroprotective role of tannoid principles of Emblica officinalis (EoT), an Indian and Chinese traditional medicinal plant against memory loss in aluminum chloride-induced in vivo model of Alzheimer's disease through attenuating AChE activity, oxidative stress, amyloid and tau toxicity, and apoptosis, was recently reported in our lab. However, to further elucidate the mechanism of neuroprotective effect of EoT, the current study was designed to evaluate endoplasmic reticulum stress-suppressing and anti-inflammatory role of EoT in PC 12 and SH-SY 5Y cells. These cells were divided into four groups: control (aluminum maltolate (Al(mal)₃), EoT + Al(mal)₃, and EoT alone based on 3-(4, 5-dimethyl 2-yl)-2, and 5-diphenyltetrazolium bromide (MTT) assay. EoT significantly reduced Al(mal)₃-induced cell death and attenuated ROS, mitochondrial membrane dysfunction, and apoptosis (protein expressions of Bax; Bcl-2; cleaved caspases 3, 6, 9, 12; and cytochrome c) by regulating endoplasmic reticulum stress (PKR-like ER kinase (PERK), α subunit of eukaryotic initiation factor 2 (EIF2-α), C/EBP-homologous protein (CHOP), and high-mobility group box 1 protein (HMGB1)). Moreover, inflammatory response (NF-κB, IL-1β, IL-6, and TNF-α) and Aβ toxicity (Aβ_1-42) triggered by Al(mal)₃ was significantly normalized by EoT. Our results suggested that EoT could be a possible/promising and novel therapeutic lead against Al-induced neurotoxicity. However, further extensive research is needed to prove its efficacy in clinical studies.

Antioxidant Activity and Neuroprotective Activity of Stilbenoids in Rat Primary Cortex Neurons via the PI3K/Akt Signalling Pathway

Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All three stilbenoids were able to inhibit Aβ neurotoxicity by decreasing intracellular reactive oxygen species (ROS) via the PI3K/Akt signalling pathway. Specifically, stilbenoids significantly promoted Akt phosphorylation; suppressed Bcl-2/Bax expression; and inhibited caspase-9, caspase-3, and PARP cleavage. Molecular docking between stilbenoids with Akt indicated that stilbenoids could form hydrogen bond interactions with the COOH-terminal region of Akt. Additionally, the neuroprotective activity of stilbenoids correlated with the number and position of hydroxyl groups. The lack of meta-dihydroxyl groups on THS did not affect its neuroprotective activity in comparison with RES, whereas the ortho-dihydroxyl moiety on PIC significantly enhanced neuroprotective activity. These results provide new insights into the correlation between the biological activity and chemical structure of stilbenoids.

Multiple pharmacological activities of Caesalpinia crista against aluminium-induced neurodegeneration in rats: Relevance for Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia and mainly affects cognitive function of the aged populations. Aluminium, a neurotoxic metal, has been suggested as a contributing factor of AD. Caesalpinia crista is a medicinal plant known for its anti-microbial, anti-inflammatory and anti-oxidant properties. The present study was conducted in order to evaluate the neuroprotective effects of methanolic extracts of C. crista (MECC) on aluminium-induced neurodegeneration in rats. Co-administration with MECC significantly and dose dependently ameliorated the aluminium-dependent cognitive impairment, AChE hyperactivity and oxidative stress in the hippocampus and in the frontal cortex of rat brain. Moreover, MECC reduced the neuronal injury induced by aluminium as shown by the diminution of neuron loss and pyknosis in the CA1 and CA3 regions of the hippocampus. From this study, it is inferred that MECC protect against aluminium-induced behavioral alterations, cognitive function, oxidative stress and neuroinflammation in vivo. Therefore, this plant may serve as a source of natural products having multiple functions and could be utilized as an anti-AD preparation.

Hyperforin attenuates aluminum-induced Aβ production and Tau phosphorylation via regulating Akt/GSK-3β signaling pathway in PC12 cells

Aluminum (Al) is a neurotoxicant and cause β-amyloid (Aβ) peptides aggregation and tau hyperphosphorylation. Hyperforin (HF) is one of the major active constituents of the extracts of St. John's Wort (Hypericum perforatum), can treat Alzheimer's disease (AD) and other diseases involving peptide accumulation and cognition impairment. To determine the effects of HF on Al-induced Aβ formation and tau hyperphosphorylation, PC12 cells were cultured and treated with Al-malt (500μM) and/or HF (1μM). The results showed that HF treatment significantly attenuated Al-malt-induced Aβ_1-42 production by reducing the expressions of APP, BACE1 and PS1, while increasing the expressions of sAPPα, ADAM9/10/17, and tau phosphorylation in PC12 cells. In addition, HF treatment also increased phosphorylation of AKT (Ser473) and inhibited GSK-3β activity by increasing phosphorylation of GSK-3β (Ser9). These results indicated that HF may exert the protection via regulating the AKT/GSK-3β signaling to reduce Aβ production and tau phosphorylation in PC12 cells. Furthermore, these results could lead a possible therapeutics for the management of Al neurotoxicity.

Synergistic effect of aluminum and ionizing radiation upon ultrastructure, oxidative stress and apoptotic alterations in Paneth cells of rat intestine

Environmental and occupational exposure to aluminum along with ionizing radiation results in serious health problems. This study was planned to investigate the impact of oxidative stress provoked by exposure to ionizing radiation with aluminum administration upon cellular ultra structure and apoptotic changes in Paneth cells of rat small intestine . Animals received daily aluminum chloride by gastric gavage at a dose 0.5 mg/Kg BW for 4 weeks. Whole body gamma irradiation was applied at a dose 2 Gy/week up to 8 Gy. Ileum malondialdehyde, advanced oxidative protein products, protein carbonyl and tumor necrosis factor-alpha were assessed as biomarkers of lipid peroxidation, protein oxidation and inflammation respectively along with superoxide dismutase, catalase, and glutathione peroxidase activities as enzymatic antioxidants. Moreover, analyses of cell cycle division and apoptotic changes were evaluated by flow cytometry. Intestinal cellular ultra structure was investigated using transmission electron microscope.Oxidative and inflammatory stresses assessment in the ileum of rats revealed that aluminum and ionizing radiation exposures exhibited a significant effect upon the increase in oxidative stress biomarkers along with the inflammatory marker tumor necrosis factor-α accompanied by a significant decreases in the antioxidant enzyme activities. Flow cytometric analyses showed significant alterations in the percentage of cells during cell cycle division phases along with significant increase in apoptotic cells. Ultra structurally, intestinal cellular alterations with marked injury in Paneth cells at the sites of bacterial translocation in the crypt of lumens were recorded. The results of this study have clearly showed that aluminum and ionizing radiation exposures induced apoptosis with oxidative and inflammatory disturbance in the Paneth cells of rat intestine, which appeared to play a major role in the pathogenesis of cellular damage. Furthermore, the interaction of these two intestinal toxic routes was found to be synergistic.

Ascorbic acid ameliorates behavioural deficits and neuropathological alterations in rat model of Alzheimer's disease

Exploring the links between neural pathobiology and behavioural deficits in Alzheimer's disease (AD), and investigating substances with known therapeutic advantages over subcellular mechanisms underlying these dysfunctions could advance the development of potent therapeutic molecules for AD treatment. Here we investigated the efficacy of ascorbic acid (AA) in reversing aluminium chloride (AlCl₃)-induced behavioural deficits and neurotoxic cascades within prefrontal cortex (PFC) and hippocampus of rats. A group of rats administered oral AlCl₃ (100mg/kg) daily for 15days showed degenerative changes characterised by significant weight loss, reduced exploratory/working memory, frontal-dependent motor deficits, cognitive decline, memory dysfunction and anxiety during behavioural assessments compared to control. Subsequent analysis showed that oxidative impairment-indicated by depleted superoxide dismutase and lipid peroxidation (related to glutathione-S-transferase activity), cholinergic deficits seen by increased neural acetylcholinesterase (AChE) expression and elevated lactate dehydrogenase underlie behavioural alterations. Furthermore, evidences of proteolysis were seen by reduced Nissl profiles in neuronal axons and dendrites which correspond to apoptotic changes observed in H&E staining of PFC and hippocampal sections. Interestingly, AA (100mg/kg daily for 15days) significantly attenuated behavioural deficits in rats through inhibition of molecular and cellular stressor proteins activated by AlCl_3. Our results showed that the primary mechanisms underlying AA therapeutic advantages relates closely with its abilities to scavenge free radicals, prevent membrane lipid peroxidation, modulate neuronal bioenergetics, act as AChE inhibitor and through its anti-proteolytic properties. These findings suggest that supplementing endogenous AA capacity through its pharmacological intake may inhibit progression of AD-related neurodegenerative processes and behavioural alterations.