The effect of curcumin (turmeric) on Alzheimer's disease: An overview

Tau proteins and senescent Cells: Targeting aging pathways in Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by abnormal accumulation of tau proteins and amyloid-β, leading to neuronal death and cognitive impairment. Recent studies have implicated aging pathways, including dysregulation of tau and cellular senescence in AD pathogenesis. In AD brains, tau protein, which normally stabilizes microtubules, becomes hyperphosphorylated and forms insoluble neurofibrillary tangles. These tau aggregates impair neuronal function and are propagated across the brain's neurocircuitry. Meanwhile, the number of senescent cells accumulating in the aging brain is rising, releasing a pro-inflammatory SASP responsible for neuroinflammation and neurodegeneration. This review explores potential therapeutic interventions for AD targeting tau protein and senescent cells, and tau -directed compounds, senolytics, eliminating senescent cells, and agents that modulate the SASP-senomodulators. Ultimately, a combined approach that incorporates tau-directed medications and targeted senescent cell-based therapies holds promise for reducing the harmful impact of AD's shared aging pathways.

Establishing network pharmacology between natural polyphenols and Alzheimer's disease using bioinformatic tools - An advancement in Alzheimer's research

Alzheimer's disease (AD) is a major cause of disability and one of the top causes of mortality globally. AD remains a major public health challenge due to its prevalence, impact on patients and caregivers, and the current lack of a cure. In recent years, polyphenols have garnered attention for their potential therapeutic effects on AD. The objective of the study was to establish network pharmacology between selected polyphenols of plant origin and AD. Insilico tools such as SwissADME, ProTox3.0, pkCSM, Swiss Target Prediction, DisGeNET, InterActiVenn, DAVID database, STRING database, Cytoscape/CytoHubba were employed to establish the multi-target potential of the polyphenolic compounds. The present study revealed that out of 17 polyphenols, 10 ligands were found to possess a drug-likeness nature along with desirable pharmacokinetic parameters and a lesser toxicity profile. Also, the results highlighted the possible interactions between the polyphenols and the disease targets involved in AD. Further, this study has shed light on the mTOR pathway and its impact on AD through the autophagic mechanism. Overall, this study indicated that polyphenols could be a better therapeutic option for treating AD. Hence, the consumption of polyphenolic cocktails as a part of the diet could produce more effective outcomes against the disease. Additional studies are warranted in the future to explore additional pathways and genes to provide a comprehensive understanding regarding the usage of the shortlisted polyphenols and their derivatives for the prevention and treatment of AD.

Effects of chain length and saturation of triacylglycerols on the characteristics and gastrointestinal digestion fates of curcumin-loaded triacylglycerol nanoparticles

This study assessed the effects of fatty acid length and saturation on the physicochemical, thermal, and gastrointestinal digestive characteristics of curcumin-loaded homo-triacylglycerol nanoparticles (C-NPs). All C-NPs had good colloidal stability and efficiently entrapped curcumin, regardless of their length and saturation. Tricaprylin NPs, with shorter chains, had a smaller size and emulsifier surface load. Curcumin was released faster from low-melting C-NPs (tricaprylin and triolein) than those with high-melting-point (trimyristin, tripalmitin, and tristearin); however, both were negligible without lipolysis. None of the C-NPs underwent significant aggregation, coalescence, or breakdown during digestion before the small intestine. Notably, longer and more saturated chains resulted in a slower initial rate and lower degree of lipolysis in the small intestine. However, greater bioaccessibility of curcumin was observed only with longer chains (tricaprylin, 70.72%; trimyristin, 78.05%; tripalmitin, 85.09%; tristearin, 89.65%; triolein, 89.71%). These findings could be valuable for the development of rational curcumin formulations for functional foods.

Glycogen synthase kinase 3 (GSK3) inhibition: a potential therapeutic strategy for Alzheimer's disease

Alzheimer's disease (AD), the most common type of dementia among older adults, is a chronic neurodegenerative pathology that causes a progressive loss of cognitive functioning with a decline of rational skills. It is well known that AD is multifactorial, so there are many different pharmacological targets that can be pursued. According to estimates from the World Health Organization (WHO), 18 million individuals worldwide suffer from AD. Major initiatives to identify risk factors, enhance care giving, and conduct basic research to delay the beginning of AD were started by the USA, France, Germany, France, and various other nations. Widely recognized as a key player in the development and subsequent progression of AD pathogenesis, glycogen synthase kinase-3 (GSK-3) controls a number of crucial targets associated with neuronal degeneration. GSK-3 inhibition has been linked to reduced tau hyperphosphorylation, β-amyloid formation, and neuroprotective benefits in Alzheimer's disease. Lithium, the very first inhibitor of GSK-3β that was used therapeutically, has been successfully used for many years with remarkable results. A great variety of structurally varied strong GSK-3β blockers have been identified in recent years. The purpose of this thorough review is to cover the biological and structural elements of glycogen synthase kinase, as well as the medicinal chemistry aspects of GSK inhibitors that have been produced in recent years.

Modulation of cholesterol metabolism with Phytoremedies in Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) is a complex neurological ailment that causes cognitive decline and memory loss. Cholesterol metabolism dysregulation has emerged as a crucial element in AD pathogenesis, contributing to the formation of amyloid-beta (Aβ) plaques and tau tangles, the disease's hallmark neuropathological characteristics. Thus, targeting cholesterol metabolism has gained attention as a potential therapeutic method for Alzheimer's disease. Phytoremedies, which are generated from plants and herbs, have shown promise as an attainable therapeutic option for Alzheimer's disease. These remedies contain bioactive compounds like phytochemicals, flavonoids, and polyphenols, which have demonstrated potential in modulating cholesterol metabolism and related pathways. This comprehensive review explores the modulation of cholesterol metabolism by phytoremedies in AD. It delves into the role of cholesterol in brain function, highlighting disruptions observed in AD. Additionally, it examines the underlying molecular mechanisms of cholesterol-related pathology in AD. The review emphasizes the significance of phytoremedies as a potential therapeutic intervention for AD. It discusses the drawbacks of current treatments and the need for alternative strategies addressing cholesterol dysregulation and its consequences. Through an in-depth analysis of specific phytoremedies, the review presents compelling evidence of their potential benefits. Molecular mechanisms underlying phytoremedy effects on cholesterol metabolism are examined, including regulation of cholesterol-related pathways, interactions with Aβ pathology, influence on tau pathology, and anti-inflammatory effects. The review also highlights challenges and future perspectives, emphasizing standardization, clinical evidence, and personalized medicine approaches to maximize therapeutic potential in AD treatment. Overall, phytoremedies offer promise as a potential avenue for AD management, but further research and collaboration are necessary to fully explore their efficacy, safety, and mechanisms of action.

Effect of curcumin-donepezil combination on spatial memory, astrocyte activation, and cholinesterase expressions in brain of scopolamine-treated rats

BACKGROUND

The study investigated the effect of co-administration of curcumin and donepezil on several markers of cognitive function (such as spatial memory, astrocyte activation, cholinesterase expressions) in the brain cortex and hippocampus of scopolamine-treated rats.

METHOD AND RESULTS

For seven consecutive days, a pre-treatment of curcumin (50 mg/kg) and/or donepezil (2.5 mg/kg) was administered. On the seventh day, scopolamine (1 mg/kg) was administered to elicit cognitive impairment, 30 min before memory test was conducted. This was followed by evaluating changes in spatial memory, cholinesterase, and adenosine deaminase (ADA) activities, as well as nitric oxide (NO) level were determined. Additionally, RT-qPCR for glial fibrillary acidic protein (GFAP) and cholinesterase gene expressions was performed in the brain cortex and hippocampus. Also, GFAP immunohistochemistry  of the brain tissues for neuronal injury were performed in the brain cortex and hippocampus. In comparison to the control group, rats given scopolamine had impaired memory, higher levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and ADA activities, as well as elevated markers of oxidative stress. In addition to enhanced GFAP immunoreactivity, there was also overexpression of the GFAP and BChE genes in the brain tissues. The combination of curcumin and donepezil was, however, observed to better ameliorate these impairments in comparison to the donepezil-administered rat group.

CONCLUSION

Hence, this evidence provides more mechanisms to support the hypothesis that the concurrent administration of curcumin and donepezil mitigates markers of cognitive dysfunction in scopolamine-treated rat model.

High-Altitude Medicinal Plants as Promising Source of Phytochemical Antioxidants to Combat Lifestyle-Associated Oxidative Stress-Induced Disorders

Oxidative stress, driven by reactive oxygen, nitrogen, and sulphur species (ROS, RNS, RSS), poses a significant threat to cellular integrity and human health. Generated during mitochondrial respiration, inflammation, UV exposure and pollution, these species damage cells and contribute to pathologies like cardiovascular issues, neurodegeneration, cancer, and metabolic syndromes. Lifestyle factors exert a substantial influence on oxidative stress levels, with mitochondria emerging as pivotal players in ROS generation and cellular equilibrium. Phytochemicals, abundant in plants, such as carotenoids, ascorbic acid, tocopherols and polyphenols, offer diverse antioxidant mechanisms. They scavenge free radicals, chelate metal ions, and modulate cellular signalling pathways to mitigate oxidative damage. Furthermore, plants thriving in high-altitude regions are adapted to extreme conditions, and synthesize secondary metabolites, like flavonoids and phenolic compounds in bulk quantities, which act to form a robust antioxidant defence against oxidative stress, including UV radiation and temperature fluctuations. These plants are promising sources for drug development, offering innovative strategies by which to manage oxidative stress-related ailments and enhance human health. Understanding and harnessing the antioxidant potential of phytochemicals from high-altitude plants represent crucial steps in combating oxidative stress-induced disorders and promoting overall wellbeing. This study offers a comprehensive summary of the production and physio-pathological aspects of lifestyle-induced oxidative stress disorders and explores the potential of phytochemicals as promising antioxidants. Additionally, it presents an appraisal of high-altitude medicinal plants as significant sources of antioxidants, highlighting their potential for drug development and the creation of innovative antioxidant therapeutic approaches.

Antioxidant, anti-inflammatory and epigenetic potential of curcumin in Alzheimer's disease

Alzheimer's disease (AD) constitutes a multifactorial neurodegenerative pathology characterized by cognitive deterioration, personality alterations, and behavioral shifts. The ongoing brain impairment process poses significant challenges for therapeutic interventions due to activating multiple neurotoxic pathways. Current pharmacological interventions have shown limited efficacy and are associated with significant side effects. Approaches focusing on the early interference with disease pathways, before activation of broad neurotoxic processes, could be promising to slow down symptomatic progression of the disease. Curcumin-an integral component of traditional medicine in numerous cultures worldwide-has garnered interest as a promising AD treatment. Current research indicates that curcumin may exhibit therapeutic potential in neurodegenerative pathologies, attributed to its potent anti-inflammatory and antioxidant properties. Additionally, curcumin and its derivatives have demonstrated an ability to modulate cellular pathways via epigenetic mechanisms. This article aims to raise awareness of the neuroprotective properties of curcuminoids that could provide therapeutic benefits in AD. The paper provides a comprehensive overview of the neuroprotective efficacy of curcumin against signaling pathways that could be involved in AD and summarizes recent evidence of the biological efficiency of curcumins in vivo.

Promising Strategies to Reduce the SARS-CoV-2 Amyloid Deposition in the Brain and Prevent COVID-19-Exacerbated Dementia and Alzheimer's Disease

The COVID-19 pandemic, caused by infection with the SARS-CoV-2 virus, is associated with cognitive impairment and Alzheimer's disease (AD) progression. Once it enters the brain, the SARS-CoV-2 virus stimulates accumulation of amyloids in the brain that are highly toxic to neural cells. These amyloids may trigger neurological symptoms in COVID-19. The meningeal lymphatic vessels (MLVs) play an important role in removal of toxins and mediate viral drainage from the brain. MLVs are considered a promising target to prevent COVID-19-exacerbated dementia. However, there are limited methods for augmentation of MLV function. This review highlights new discoveries in the field of COVID-19-mediated amyloid accumulation in the brain associated with the neurological symptoms and the development of promising strategies to stimulate clearance of amyloids from the brain through lymphatic and other pathways. These strategies are based on innovative methods of treating brain dysfunction induced by COVID-19 infection, including the use of photobiomodulation, plasmalogens, and medicinal herbs, which offer hope for addressing the challenges posed by the SARS-CoV-2 virus.

Heavy metals toxicity on epigenetic modifications in the pathogenesis of Alzheimer's disease (AD)

Alzheimer's disease (AD) is a progressive decline in cognitive ability and behavior which eventually disrupts daily activities. AD has no cure and the progression rate varies unlikely. Among various causative factors, heavy metals are reported to be a significant hazard in AD pathogenesis. Metal-induced neurodegeneration has been focused globally with thorough research to unravel the mechanistic insights in AD. Recently, heavy metals suggested to play an important role in epigenetic alterations which might provide evidential results on AD pathology. Epigenetic modifications are known to play towards novel therapeutic approaches in treating AD. Though many studies focus on epigenetics and heavy metal implications in AD, there is a lack of research on heavy metal influence on epigenetic toxicity in neurological disorders. The current review aims to elucidate the plausible role of cadmium (Cd), iron (Fe), arsenic (As), copper (Cu), and lithium (Li) metals on epigenetic factors and the increase in amyloid beta and tau phosphorylation in AD. Also, the review discusses the common methods of heavy metal detection to implicate in AD pathogenesis. Hence, from this review, we can extend the need for future research on identifying the mechanistic behavior of heavy metals on epigenetic toxicity and to develop diagnostic and therapeutic markers in AD.

Epigenetic and gene therapy in human and veterinary medicine

Gene therapy is a focus of interest in both human and veterinary medicine, especially in recent years due to the potential applications of CRISPR/Cas9 technology. Another relatively new approach is that of epigenetic therapy, which involves an intervention based on epigenetic marks, including DNA methylation, histone post-translational modifications, and post-transcription modifications of distinct RNAs. The epigenome results from enzymatic reactions, which regulate gene expression without altering DNA sequences. In contrast to conventional CRISP/Cas9 techniques, the recently established methodology of epigenetic editing mediated by the CRISPR/dCas9 system is designed to target specific genes without causing DNA breaks. Both natural epigenetic processes and epigenetic editing regulate gene expression and thereby contribute to maintaining the balance between physiological functions and pathophysiological states. From this perspective, knowledge of specific epigenetic marks has immense potential in both human and veterinary medicine. For instance, the use of epigenetic drugs (chemical compounds with therapeutic potential affecting the epigenome) seems to be promising for the treatment of cancer, metabolic, and infectious diseases. Also, there is evidence that an epigenetic diet (nutrition-like factors affecting epigenome) should be considered as part of a healthy lifestyle and could contribute to the prevention of pathophysiological processes. In summary, epigenetic-based approaches in human and veterinary medicine have increasing significance in targeting aberrant gene expression associated with various diseases. In this case, CRISPR/dCas9, epigenetic targeting, and some epigenetic nutrition factors could contribute to reversing an abnormal epigenetic landscape to a healthy physiological state.

Navigating neurological disorders: harnessing the power of natural compounds for innovative therapeutic breakthroughs

Novel treatments are needed as neurological issues become more frequent worldwide. According to the report, plants, oceans, microorganisms, and animals contain interesting drug discovery compounds. Alzheimer's, Parkinson's, and stroke reviews emphasize neurological disorders' complexity and natural substances' safety. Learn about marine-derived and herbal substances' neuroprotective characteristics and applications. Molecular pathways show these substances' neurological healing effects. This article discusses clinical usage of Bryostatin-1, Fucoidan, Icariin, Salvianolic acid, Curcumin, Resveratrol, etc. Their potential benefits for asthma and Alzheimer's disease are complex. Although limited, the study promotes rigorous scientific research and collaboration between traditional and alternative medical practitioners. Unexplored natural compounds, quality control, well-structured clinical trials, and interdisciplinary collaboration should guide future study. Developing and employing natural chemicals to treat neurological illnesses requires ethical sourcing, sustainability, and public awareness. This detailed analysis covers natural chemicals' current state, challenges, and opportunities in neurological disorder treatment. See also the graphical abstract(Fig. 1).

Alzheimer's Disease and COVID-19 Pathogenic Overlap: Implications for Drug Repurposing

As COVID-19 continues, a safe, cost-effective treatment strategy demands continued inquiry. Chronic neuroinflammatory disorders may appear to be of little relevance in this regard; often indolent and progressive disorders characterized by neuroinflammation (such as Alzheimer's disease (AD)) are fundamentally dissimilar in etiology and symptomology to COVID-19's rapid infectivity and pathology. However, the two disorders share extensive pathognomonic features, including at membrane, cytoplasmic, and extracellular levels, culminating in analogous immunogenic destruction of their respective organ parenchyma. We hypothesize that these mechanistic similarities may extent to therapeutic targets, namely that it is conceivable an agent against AD's immunopathy may have efficacy against COVID-19 and vice versa. It is notable that while extensively investigated, no agent has yet demonstrated significant therapeutic efficacy against AD's cognitive and memory declines. Yet this very failure has driven the development of numerous agents with strong mechanistic potential and clinical characteristics. Having already approved for clinical trials, these agents may be an expedient starting point in the urgent search for an effective COVID-19 therapy. Herein, we review the overlapping Alzheimer's/ COVID-19 targets and theorize several initial platforms.

Promising Potential of Curcumin and Related Compounds for Antiviral Drug Discovery

Viruses are acellular, microscopic, and mobile particles containing genetic particles, either DNA/RNA strands as nucleoproteins, responsible for 69,53,743 deaths till the year 2023. Curcumin and related compounds are among the areas of pivotal interest for researchers because of their versatile pharmacological profile. Chemically known as diferuloylmethane, which is a main constituent of turmeric along with demethoxycurcumin and bisdemethoxycurcumin, they have a broad spectrum of antiviral activity against viruses such as human immunodeficiency virus, herpes simplex virus, influenza virus (Avian influenza) and Hepatitis C virus HIV. The possible role of curcumin as an antiviral agent may be attributed to the activation of the 20S proteasome, a cellular machinery responsible for degrading unfolded or misfolded proteins in a ubiquitin-independent manner. It shows suppression of HBV entry at various infection stages by inhibiting cccDNA replication by inhibiting the Wnt/β-catenin signaling pathway to attenuate IAV-induced myocarditis.

Targeting Amyloids with Coated Nanoparticles: A Review on Potential Combinations of Nanoparticles and Bio-Compatible Coatings

Amyloidosis is the major cause of many neurodegenerative diseases, such as, Alzheimer's and Parkinson's where the misfolding and deposition of a previously functional protein make it inept for carrying out its function. The genesis of amyloid fibril formation and the strategies to inhibit it have been studied extensively, although some parts of this puzzle still remain unfathomable to date. Many classes of molecules have been explored as potential drugs in vitro, but their inability to work in vivo by crossing the blood-brain-barrier has made them an inadequate treatment option. In this regard, nanoparticles (NPs) have turned out to be an exciting alternative because they could overcome many drawbacks of previously studied molecules and provide advantages, such as, greater bioavailability of molecules and target-specific delivery of drugs. In this paper, we present an overview on several coated NPs which have shown promising efficiency in inhibiting fibril formation. A hundred and thirty papers published in the past two decades have been comprehensively reviewed, which majorly encompass NPs comprising different materials like gold, silver, iron-oxide, poly(lactic-co-glycolic acid), polymeric NP, etc., which are coated with various molecules of predominantly natural origin, such as different types of amino acids, peptides, curcumin, drugs, catechin, etc. We hope that this review will shed light on the advancement of symbiotic amalgamation of NPs with molecules from natural sources and will inspire further research on the tremendous therapeutic potential of these combinations for many amyloid-related diseases.

Polyphenols and Diets as Current and Potential Nutrition Senotherapeutics in Alzheimer's Disease: Findings from Clinical Trials

Cellular senescence, a hallmark of aging, plays an important role in age-related conditions among older adults. Targeting senescent cells and its phenotype may provide a promising strategy to delay the onset or progression of Alzheimer's disease (AD). In this review article, we investigated efficacy and safety of nutrition senotherapy in AD, with a focus on the role of polyphenols as current and potential nutrition senotherapeutic agents, as well as relevant dietary patterns. Promising results with neuroprotective effects of senotherapeutic agents such as quercetin, resveratrol, Epigallocatechin-gallate, curcumin and fisetin were reported from preclinical studies. However, in-human trials remain limited, and findings were inconclusive. In future, nutrition senotherapeutic agents should be studied both individually and within dietary patterns, through the perspective of cellular senescence and AD. Further studies are warranted to investigate bioavailability, dosing regimen, long term effects of nutrition senotherapy and provide better understanding of the underlying mechanisms. Collaboration between researchers needs to be established, and methodological limitations of current studies should be addressed.

Marine-derived Compounds: A Powerful Platform for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a debilitating form of dementia that primarily affects cholinergic neurons in the brain, significantly reducing an individual's capacity for learning and creative skills and ultimately resulting in an inability to carry out even basic daily tasks. As the elderly population is exponentially increasing, the disease has become a significant concern for society. Therefore, neuroprotective substances have garnered considerable interest in addressing this universal issue. Studies have shown that oxidative damage to neurons contributes to the pathophysiological processes underlying AD progression. In AD, tau phosphorylation and glutamate excitotoxicity may play essential roles, but no permanent cure for AD is available. The existing therapies only manage the early symptoms of AD and often come with numerous side effects and toxicities. To address these challenges, researchers have turned to nature and explored various sources such as plants, animals, and marine organisms. Many historic holy books from different cultures emphasize that adding marine compounds to the regular diet enhances brain function and mitigates its decline. Consequently, researchers have devoted significant time to identifying potentially active neuroprotective substances from marine sources. Marine-derived compounds are gaining recognition due to their abundant supply of diverse chemical compounds with biological and pharmacological potential and unique mechanisms of action. Several studies have reported that plants exhibit multitarget potential in treating AD. In light of this, the current study focuses on marine-derived components with excellent potential for treating this neurodegenerative disease.

α-bisabolol β-d-fucopyranoside (ABFP) ameliorates scopolamine-induced memory deficits through cholinesterase inhibition and attenuation of oxidative stress in zebrafish (Danio rerio)

Alzheimer's disease (AD) is one of the major devastating neurodegenerative disorders associated with the gradual decline of an individual's memory, cognition, and ability to carry out day-to-day activities. In the present study, the neuroprotective ability of α-bisabolol β-d-fucopyranoside (ABFP) was assessed via measurement of antioxidant parameters like lipid peroxidation, glutathione peroxidation, glutathione, protein carbonyl content assays, and caspase-3 activity estimation. Moreover, the acute toxicity of ABFP was estimated in the zebrafish larval model. The results showed that ABFP exhibits little to no toxicity at lower concentrations in the acute toxicity test. ABFP-pretreated and scopolamine-exposed fish exhibited more exploratory behavior in the behavior assay than scopolamine-only induced groups. Additionally, the results of antioxidant enzyme assays revealed reduced oxidative stress and damage in ABFP-treated fish, while enzyme activity experiments carried out with brain homogenate from ABFP-treated fish showed decreased acetylcholinesterase enzyme activity. Overall, it can be concluded that ABFP has the potential to be a promising agent for the treatment of AD in the future.

Role of multi-targeted bioactive natural molecules and their derivatives in the treatment of Alzheimer's disease: an insight into structure-activity relationship

Alzheimer's disease (AD) is a complex neurodegenerative disorder involving cognitive dysfunction like short-term memory and behavioral changes as the disease progresses due to other unaltered physiological factors. The solution for this problem is Multi-targeted Drugs (MTDs), which can affect multiple determinants to realize the multifunctional effects. Acetylcholinesterase (AChE) inhibitors donepezil, rivastigmine, galantamine, and N-methyl-D-aspartate (NMDA) receptor antagonist memantine are FDA-approved drugs used to treat AD symptomatically. The key objective of this review is to understand multitargeted bioactive natural molecules that could be considered as leads for further development as effective drugs for treating AD, along with understanding its pharmacology and structure-activity relationship (SAR). Understanding the molecular mechanism of the AD pathophysiology, the role of existing drugs, treatment of AD via amyloid beta (Aβ) plaque, and neurofibrillary tangle (NFT) inhibition by natural bioactive molecules were also discussed in the review. The current quest and recent advancements with natural bioactive compounds like physostigmine, resveratrol, curcumin, and catechins, along with the study of in silico SAR, were reported in the present study. This review summarises the structural properties required for bioactive natural molecules to show anti-Alzheimer's activity by emphasizing on SAR of several bioactive natural molecules targeting various AD pathologies, their key molecular interactions that are critical for target specificity, their role as multitargeted ligands, used with adjunctive therapy for AD followed by related US patents granted recently. This article highlights the significance of the structural features of natural bioactive molecules in the treatment of AD and establishes a connection between them.Communicated by Ramaswamy H. Sarma.

Therapeutic considerations of bioactive compounds in Alzheimer's disease and Parkinson's disease: Dissecting the molecular pathways

Leading neurodegenerative diseases Alzheimer's disease (AD) and Parkinson's disease (PD) are characterized by the impairment of memory and motor functions, respectively. Despite several breakthroughs, there exists a lack of disease-modifying treatment strategies for these diseases, as the available drugs provide symptomatic relief and bring along side effects. Bioactive compounds are reported to bear neuroprotective properties with minimal toxicity, however, a detailed elucidation of their modes of neuroprotection is lacking. The review elucidates the neuroprotective mechanism(s) of some of the major phyto-compounds in pre-clinical and clinical studies of AD and PD to understand their potential in combating these diseases. Curcumin, eugenol, resveratrol, baicalein, sesamol and so on have proved efficient in countering the pathological hallmarks of AD and PD. Curcumin, resveratrol, caffeine and so on have reached the clinical phases of these diseases, while aromadendrin, delphinidin, cyanidin and xanthohumol are yet to be extensively explored in pre-clinical phases. The review highlights the need for extensive investigation of these compounds in the clinical stages of these diseases so as to utilize their disease-modifying abilities in the real field of treatment. Moreover, poor pharmacokinetic properties of natural compounds are constraints to their therapeutic yields and this review suggests a plausible contribution of nanotechnology in overcoming these limitations.

Curcumin improves the ability of donepezil to ameliorate memory impairment in Drosophila melanogaster: involvement of cholinergic and cnc/Nrf2-redox systems

One of the well-established models for examining neurodegeneration and neurotoxicity is the Drosophila melanogaster model of aluminum-induced toxicity. Anti-cholinesterase drugs have been combined with other neuroprotective agents to improve Alzheimer's disease management, but there is not much information on the combination of anti-cholinesterases with dietary polyphenols to combat memory impairment. Here, we assess how curcumin influences some of the critical therapeutic effects of donepezil (a cholinesterase inhibitor) in AlCl3-treated Drosophila melanogaster. Harwich strain flies were exposed to 40 mM AlCl3 - alone or in combination with curcumin (1 mg/g) and/or donepezil (12.5 µg/g and 25 µg/g) - for seven days. The flies' behavioral evaluations (memory index and locomotor performance) were analyzed. Thereafter, the flies were processed into homogenates for the quantification of acetylcholinesterase (AChE), catalase, total thiol, and rate of lipid peroxidation, as well as the mRNA levels of acetylcholinesterase (ACE1) and cnc/NRF2. Results showed that AlCl3-treated flies presented impaired memory and increased activities of acetylcholinesterase and lipid peroxidation, while there were decrease in total thiol levels and catalase activity when compared to the control. Also, the expression of ACE1 was significantly increased while that of cnc/NRF2 was significantly decreased. However, combinations of curcumin and donepezil, especially at lower dose of donepezil, significantly improved the memory index and biochemical parameters compared to donepezil alone. Thus, curcumin plus donepezil offers unique therapeutic effects during memory impairment in the D. melanogaster model of neurotoxicity.

Autophagy Modulation and Its Implications on Glioblastoma Treatment

Autophagy is a vital cellular process that functions to degrade and recycle damaged organelles into basic metabolites. This allows a cell to adapt to a diverse range of challenging conditions. Autophagy assists in maintaining homeostasis, and it is tightly regulated by the cell. The disruption of autophagy has been associated with many diseases, such as neurodegenerative disorders and cancer. This review will center its discussion on providing an in-depth analysis of the current molecular understanding of autophagy and its relevance to brain tumors. We will delve into the current literature regarding the role of autophagy in glioma pathogenesis by exploring the major pathways of JAK2/STAT3 and PI3K/AKT/mTOR and summarizing the current therapeutic interventions and strategies for glioma treatment. These treatments will be evaluated on their potential for autophagy induction and the challenges associated with their utilization. By understanding the mechanism of autophagy, clinical applications for future therapeutics in treating gliomas can be better targeted.

Chronic supplementation of a multi-ingredient herbal supplement increases speed of cognitive task performance alongside changes in the urinary metabolism of dopamine and the gut microbiome in cognitively intact older adults experiencing subjective memory decline: a randomized, placebo controlled, parallel groups investigation

Background

The effects of herbs on brain function are often investigated in isolation, yet herbal preparations are often complex combinations of phytochemicals, designed to target widespread mechanisms.

Objective

To assess the effects of chronic, 12 weeks, supplementation of a multi-ingredient herbal supplement (containing Bacopa monnieri, Gotu kola leaf, Turmeric whole powder, Reishi full spectrum, Rosemary, Cardamom, Holy Basil, Turmeric Wholistic™ extract, Green Tea & Seagreens) on cognitive function in older adults with subjective memory decline. Secondly, to investigate whether effects are underpinned by shifts in microbial composition and/or metabolism of the herbs.

Methods

Male and female participants (N = 128) aged between 55-75 years completed lab-based cognitive assessments, and provided stool and urine samples, at baseline and then following 90 days of multi-ingredient herb, or placebo, supplementation.

Results

Deficits in memory were observed in response to 90 days of multi-ingredient herbal supplement supplementation but the positive effects were all focused on speed of cognitive task performance, with an additional improvement in the false alarm rate on the rapid visual information processing task. These improvements coincided with an increased presence of tyrosine in the urinary metabolome and this may implicate the role of dopamine in these processing and/or motor speed increases. Finally, multi-ingredient herbal supplementation significantly reduced levels of 3 bacterial species in the gut microbiome and one of these, Sutterella, coincides with lower levels of constipation reported in the multi-ingredient herbal supplement condition.

Conclusion

A multi-ingredient herbal supplement increases speed of cognitive task performance and increased metabolism of tyrosine suggests that this is modulated by increased dopaminergic activity. Reduced levels of Sutterella in the gut is associated with improved bowel movements of participants. Interpretation of the negative effects on memory are, however, stymied by an unequal randomization of participants into treatment groups pre- and post-COVID 19.Clinical trial registration: identifier NCT05504668.

The Homoleptic Curcumin-Copper Single Crystal (ML2): A Long Awaited Breakthrough in the Field of Curcumin Metal Complexes

The first single crystal structure of the homoleptic copper (II) ML2 complex (M=Cu (II), L = curcumin) was obtained and its structure was elucidated by X-ray diffraction showing a square planar geometry, also confirmed by EPR. The supramolecular arrangement is supported by C-H···O interactions and the solvent (MeOH) plays an important role in stabilizing the crystal packing Crystallinity was additionally assessed by XRD patterns. The log P value of the complex (2.3 ± 0.15) was determined showing the improvement in water solubility. The cytotoxic activity of the complex against six cancer cell lines substantially surpasses that of curcumin itself, and it is particularly selective against leukemia (K562) and human glioblastoma (U251) cell lines, with similar antioxidant activity to BHT. This constitutes the first crystal structure of pristine curcumin complexed with a metal ion.

Anti-Inflammatory Effects of Dietary Polyphenols through Inhibitory Activity against Metalloproteinases

Matrix metalloproteinases (MMPs) are zinc-dependent metalloproteinases that play important roles in a variety of diseases, including cancer, cardiovascular disease, diabetes, obesity, and brain diseases. Dietary polyphenols are thought to have a variety of beneficial effects on these diseases characterized by inflammation. Clinical studies have demonstrated that MMPs are in most cases upregulated in various inflammatory diseases, including osteoarthritis, rheumatoid arthritis, inflammatory bowel disease, and Alzheimer's disease. Studies using patient-derived human samples, animal studies, and cellular experiments have suggested that polyphenols may be beneficial against inflammatory diseases by suppressing MMP gene expression and enzyme activity. One important mechanism by which polyphenols exert their activity is the downregulation of reactive oxygen species that promote MMP expression. Another important mechanism is the direct binding of polyphenols to MMPs and their inhibition of enzyme activity. Molecular docking analyses have provided a structural basis for the interaction between polyphenols and MMPs and will help to explore new polyphenol-based drugs with anti-inflammatory properties.

Nicotinamide ameliorates mitochondria-related neuronal apoptosis and cognitive impairment via the NAD+/SIRT3 pathway

Emerging evidence suggests that mitochondria play a central role in mental health disorders including schizophrenia. Here we investigated whether nicotinamide (NAM) normalized cognitive impairment via a mechanism involving the mitochondrial Sirtuin 3 (SIRT3) pathway. The 24 h maternal separation (MS) rat model was used to mimic schizophrenia-associate phenotypes. Schizophrenia-like behaviors and memory impairments were detected using the pre-pulse inhibition test, novel object recognition test, and Barnes maze test, and neuronal apoptosis was characterized using multiple assays. SIRT3 activity was inhibited pharmacologically or by knockdown in HT22 cells, and BV2 microglia and SIRT3-knockdown HT22 cells were co-cultured in vitro. Mitochondrial molecules were measured by western blotting, and mitochondrial damage was measured with reactive oxygen species and mitochondrial membrane potential assays. Proinflammatory cytokines were assayed by ELISA and microglial activation was detected by immunofluorescence. MS animals showed behavioral and cognitive impairment and increased neuronal apoptosis. Supplementation with NAM or administration of honokiol, a SIRT3 activator, reversed all of the changes in behavioral and neuronal phenotypes. Administration of the SIRT3 inhibitor 3-TYP in control and NAM-treated MS rats caused behavioral and neuronal phenotypes similar to MS. In vitro, inhibition of SIRT3 activity with 3-TYP or by knockdown in HT22 cells increased ROS accumulation and caused neuronal apoptosis in a single-culture system. In co-culture systems, SIRT3 knockdown in HT22 cells activated BV2 microglia and increased levels of TNF-α, IL-6, and IL-1β. The administration of NAM blocked these alterations. Taken together, these data suggest that NAM can rescue neuronal apoptosis and microglial over-activation through the nicotinamide adenine dinucleotide (NAD⁺)-SIRT3-SOD2 signaling pathway, furthering our understanding of the pathogenesis of schizophrenia and providing avenues for novel treatments.

Phytochemicals: A Promising Alternative for the Prevention of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that worsens with ageing and affects memory and cognitive function. Presently more than 55 million individuals are affected by AD all over the world, and it is a leading cause of death in old age. The main purpose of this paper is to review the phytochemical constituents of different plants that are used for the treatment of AD. A thorough and organized review of the existing literature was conducted, and the data under the different sections were found using a computerized bibliographic search through the use of databases such as PubMed, Web of Science, Google Scholar, Scopus, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS, and numerous other websites. Around 360 papers were screened, and, out of that, 258 papers were selected on the basis of keywords and relevant information that needed to be included in this review. A total of 55 plants belonging to different families have been reported to possess different bioactive compounds (galantamine, curcumin, silymarin, and many more) that play a significant role in the treatment of AD. These plants possess anti-inflammatory, antioxidant, anticholinesterase, and anti-amyloid properties and are safe for consumption. This paper focuses on the taxonomic details of the plants, the mode of action of their phytochemicals, their safety, future prospects, limitations, and sustainability criteria for the effective treatment of AD.

Nanomedicine-driven therapeutic interventions of autophagy and stem cells in the management of Alzheimer's disease

Drug-loaded, brain-targeted nanocarriers could be a promising tool in overcoming the challenges associated with Alzheimer's disease therapy. These nanocargoes are enormously flexible to functionalize and facilitate the delivery of drugs to brain cells by bridging the blood-brain barrier and into brain cells. To date, modifications have included nanoparticles (NPs) coating with tunable surfactants/phospholipids, covalently attaching polyethylene glycol chains (PEGylation), and tethering different targeting ligands to cell-penetrating peptides in a manner that facilitates their entry across the BBB and downregulates various pathological hallmarks as well as intra- and extracellular signaling pathways. This review provides a brief update on drug-loaded, multifunctional nanocarriers and the therapeutic intervention of autophagy and stem cells in the management of Alzheimer's disease.

The effect of curcumin supplementation on weight loss and anthropometric indices: an umbrella review and updated meta-analyses of randomized controlled trials

BACKGROUND

Curcumin supplementation may promote weight loss and ameliorate obesity-related complications through its antioxidative and anti-inflammatory properties.

OBJECTIVE

An umbrella review and updated meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate the effect of curcumin supplementation on anthropometric indices.

METHODS

Systematic reviews and meta-analyses (SRMAs) of RCTs were identified from electronic databases (Medline, Scopus, Cochrane, and Google Scholar) up to 31 March, 2022, without language restriction. SRMAs were included if they assessed curcumin supplementation on any of the following: BMI, body weight (BW), or waist circumference (WC). Subgroup analyses were performed, stratifying by patient types, severity of obesity, and curcumin formula. The study protocol was a priori registered.

RESULTS

From an umbrella review, 14 SRMAs with 39 individual RCTs were included with a high degree of overlap. In addition, searching was updated from the last search of included SRMAs in April 2021 up to 31 March, 2022, and we found 11 additional RCTs, bringing the total up to 50 RCTs included in the updated meta-analyses. Of these, 21 RCTs were deemed of high risk of bias. Curcumin supplementation significantly reduced BMI, BW, and WC with mean differences (MDs) of -0.24 kg/m² (95% CI: -0.32, -0.16 kg/m²), -0.59 kg (95% CI: -0.81, -0.36 kg), and -1.32 cm (95% CI: -1.95, -0.69 cm), respectively. The bioavailability-enhanced form reduced BMI, BWs, and WC more, with MDs of -0.26 kg/m² (95% CI: -0.38, -0.13 kg/m²), -0.80 kg (95% CI: -1.38, -0.23 kg) and -1.41 cm (95% CI: -2.24, -0.58 cm), respectively. Significant effects were also seen in subgroups of patients, especially in adults with obesity and diabetes.

CONCLUSIONS

Curcumin supplementation significantly reduces anthropometric indices, and bioavailability-enhanced formulas are preferred. Augmenting curcumin supplement with lifestyle modification should be an option for weight reduction. This trial was registered at PROSPERO as CRD42022321112 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022321112).

AL-Johani N, Alarifi S, Afzal M. Cytotoxicity Mechanisms of Blue-Light-Activated Curcumin in T98G Cell Line: Inducing Apoptosis through ROS-Dependent Downregulation of MMP Pathways

We examined the photodynamic activation of Curcumin under blue light in glioblastoma T98G cells. The therapeutic effect of Curcumin, in both the absence and presence of blue light, was measured by the MTT assay and apoptosis progression using flow cytometry. Fluorescence imaging was carried out to evaluate Curcumin uptake. Photodynamic activation of Curcumin (10 µM), in the presence of blue light, enhanced its cytotoxic effect, resulting in the activation of ROS-dependent apoptotic pathways in T98G cells. The gene expression studies showed the expression of matrixes metalloproteinase 2 (MMP2) and 9 (MMP9) decrease with Curcumin (10 µM) under blue light exposure, indicating possible proteolytic mechanisms. Moreover, the cytometric appearance displayed that the expressions of NF-κB and Nrf2 were found to be increased upon exposure to blue light, which revealed a significant induction of expression of nuclear factor as a result of blue-light-induced oxidative stress and cell death. These data further demonstrate that Curcumin exhibited a photodynamic effect via induction of ROS-mediated apoptosis in the presence of blue light. Our results suggest that the application of blue light enhances the therapeutic efficacy of Curcumin in glioblastoma because of the phototherapeutic effect.

Honey and Alzheimer's Disease-Current Understanding and Future Prospects

Alzheimer's disease (AD), a leading cause of dementia, has been a global concern. AD is associated with the involvement of the central nervous system that causes the characteristic impaired memory, cognitive deficits, and behavioral abnormalities. These abnormalities caused by AD is known to be attributed by extracellular aggregates of amyloid beta plaques and intracellular neurofibrillary tangles. Additionally, genetic factors such as abnormality in the expression of APOE, APP, BACE1, PSEN-1, and PSEN-2 play a role in the disease. As the current treatment aims to treat the symptoms and to slow the disease progression, there has been a continuous search for new nutraceutical agent or medicine to help prevent and cure AD pathology. In this quest, honey has emerged as a powerful nootropic agent. Numerous studies have demonstrated that the high flavonoids and phenolic acids content in honey exerts its antioxidant, anti-inflammatory, and neuroprotective properties. This review summarizes the effect of main flavonoid compounds found in honey on the physiological functioning of the central nervous system, and the effect of honey intake on memory and cognition in various animal model. This review provides a new insight on the potential of honey to prevent AD pathology, as well as to ameliorate the damage in the developed AD.

The Quest for Neurodegenerative Disease Treatment-Focusing on Alzheimer's Disease Personalised Diets

Dementia represents a clinical syndrome characterised by progressive decline in memory, language, visuospatial and executive function, personality, and behaviour, causing loss of abilities to perform instrumental or essential activities of daily living. The most common cause of dementia is Alzheimer's disease (AD), which accounts for up to 80% of all dementia cases. Despite that extensive studies regarding the etiology and risk factors have been performed in recent decades, and how the current knowledge about AD pathophysiology significantly improved with the recent advances in science and technology, little is still known about its treatment options. In this controverted context, a nutritional approach could be a promising way to formulate improved AD management strategies and to further analyse possible treatment strategy options based on personalised diets, as Nutritional Psychiatry is currently gaining relevance in neuropsychiatric disease treatment. Based on the current knowledge of AD pathophysiology, as well as based on the repeatedly documented anti-inflammatory and antioxidant potential of different functional foods, we aimed to find, describe, and correlate several dietary compounds that could be useful in formulating a nutritional approach in AD management. We performed a screening for relevant studies on the main scientific databases using keywords such as "Alzheimer's disease", "dementia", "treatment", "medication", "treatment alternatives", "vitamin E", "nutrition", "selenium", "Ginkgo biloba", "antioxidants", "medicinal plants", and "traditional medicine" in combinations. Results: nutrients could be a key component in the physiologic and anatomic development of the brain. Several nutrients have been studied in the pursuit of the mechanism triggered by the pathology of AD: vitamin D, fatty acids, selenium, as well as neuroprotective plant extracts (i.e., Ginkgo biloba, Panax ginseng, Curcuma longa), suggesting that the nutritional patterns could modulate the cognitive status and provide neuroprotection. The multifactorial origin of AD development and progression could suggest that nutrition could greatly contribute to the complex pathological picture. The identification of adequate nutritional interventions and the not yet fully understood nutrient activity in AD could be the next steps in finding several innovative treatment options for neurodegenerative disorders.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

Structure-activity relationship of dibenzylideneacetone analogs against the neglected disease pathogen, Trypanosoma brucei

Trypanosoma brucei is a protozoan parasite that causes Human African Trypanosomiasis (HAT), a neglected tropical disease (NTD) that is endemic in 36 countries in sub-Saharan Africa. Only a handful drugs are available for treatment, and these have limitations, including toxicity and drug resistance. Using the natural product, curcumin, as a starting point, several curcuminoids and related analogs were evaluated against bloodstream forms of T. b. brucei. A particular subset of dibenzylideneacetone (DBA) compounds exhibited potent in vitro antitrypanosomal activity with sub-micromolar EC₅₀ values. A structure-activity relationship study including 26 DBA analogs was initiated, and several compounds exhibited EC₅₀ values as low as 200 nM. Cytotoxicity counter screens in HEK293 cells identified several compounds having selectivity indices above 10. These data suggest that DBAs offer starting points for a new small molecule therapy of HAT.

Formulation and Development of Curcumin-Piperine-Loaded S-SNEDDS for the Treatment of Alzheimer's Disease

Curcumin (CUR) and piperine (PIP) are very well-known phytochemicals that claimed to have many health benefits and have been widely used in foods and traditional medicines. This study investigated the therapeutic efficacy of these compounds to treat Alzheimer's disease (AD). However, poor oral bioavailability and permeability of curcumin are a major challenge for formulation scientists. In this research study, the researcher tried to enhance the bioavailability and permeability of curcumin by a nanotechnological approach. In this research study, we developed a CUR-PIP-loaded SNEDDS in various oils. Optimised formulation NF3 was subjected to evaluate its therapeutic effectiveness on AD animal model in comparison with untreated AD model and treated group (by market formulation donepezil). On the basis of characterisation results, it is confirmed that NF3 formulation is the best formulation. The optimised formulation shows a significant dose-dependent manner therapeutic effect on AD-induced model. Novel formulation CUR-PIP solid-SNEDDS was successfully developed and optimised. It is expected that the developed S-SNEDDS can be a potential, safe and effective carrier for the oral delivery of curcumin to the brain. To date, this article is the only study of CUR-PIP-loaded S-SNEDDS for the treatment of AD.

Oxidative Stress and Natural Antioxidants: Back and Forth in the Neurological Mechanisms of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the progressive degeneration of neuronal cells. With the increase in aged population, there is a prevalence of irreversible neurodegenerative changes, causing a significant mental, social, and economic burden globally. The factors contributing to AD are multidimensional, highly complex, and not completely understood. However, it is widely known that aging, neuroinflammation, and excessive production of reactive oxygen species (ROS), along with other free radicals, substantially contribute to oxidative stress and cell death, which are inextricably linked. While oxidative stress is undeniably important in AD, limiting free radicals and ROS levels is an intriguing and potential strategy for deferring the process of neurodegeneration and alleviating associated symptoms. Therapeutic compounds from natural sources have recently become increasingly accepted and have been effectively studied for AD treatment. These phytocompounds are widely available and a multitude of holistic therapeutic efficiencies for treating AD owing to their antioxidant, anti-inflammatory, and biological activities. Some of these compounds also function by stimulating cholinergic neurotransmission, facilitating the suppression of beta-site amyloid precursor protein-cleaving enzyme 1, α-synuclein, and monoamine oxidase proteins, and deterring the occurrence of AD. Additionally, various phenolic, flavonoid, and terpenoid phytocompounds have been extensively described as potential palliative agents for AD progression. Preclinical studies have shown their involvement in modulating the cellular redox balance and minimizing ROS formation, displaying them as antioxidant agents with neuroprotective abilities. This review emphasizes the mechanistic role of natural products in the treatment of AD and discusses the various pathological hypotheses proposed for AD.

Neuropharmacological Study on Capsaicin in Scopolamine-injected Mice

AIM

To evaluate the potential beneficial role of Capsaicin in cognitive dysfunction, mitochondrial impairment, and oxidative damage induced by scopolamine in mice.

BACKGROUND

Capsaicin is the chief phenolic component present in red chili and is responsible for its pungent and spicy flavor. It affects TRPV1 channels in nociceptive sensory neurons and is present in the hippocampus, and hypothalamus of the brains of rodents and humans.

OBJECTIVE

The main objective is to investigate the effective role of capsaicin in attenuating cognitive dysfunction, mitochondrial impairment, and oxidative damage induced by scopolamine in mice and examine the feasible mechanisms.

METHODS

Various doses of capsaicin (5, 10, and 20 mg/kg) were given orally to mice daily for 7 consecutive days after the administration of scopolamine. Various behavioral tests (motor coordination, locomotor counts, hole board test) and biochemical assay (Pro-inflammatory cytokines, catalase, lipid peroxidation, nitrite, reduced glutathione, and superoxide dismutase), mitochondrial complex (I, II, III, and IV) enzyme activities, and mitochondrial permeability transition were evaluated in the distinct regions of the brain.

RESULTS

Scopolamine-treated mice showed a considerable reduction in the entries and duration in the light zone as well as in open arms of the elevated plus maze. Interestingly, capsaicin at different doses reversed the anxiety, depressive-like behaviors, and learning and memory impairment effects of scopolamine. Scopolamine-administered mice demonstrated substantially increased pro-inflammatory cytokines levels, impaired mitochondrial enzyme complex activities, and increased oxidative damage compared to the normal control group. Capsaicin treatment reinstated the reduced lipid peroxidation, nitric oxide, catalase, superoxide dismutase, reduced glutathione activity, decreasing pro-inflammatory cytokines and restoring mitochondrial complex enzyme activities (I, II, III, and IV) as well as mitochondrial permeability. Moreover, the IL-1β level was restored at a dose of capsaicin (10 and 20 mg/kg) only. Capsaicin reduced the scopolamine-induced acetylcholinesterase activity, thereby raising the acetylcholine concentration in the hippocampal tissues of mice. Preservation of neuronal cell morphology was also confirmed by capsaicin in histological studies. From the above experimental results, capsaicin at a dose of 10 mg/kg, p.o. for seven consecutive days was found to be the most effective dose.

CONCLUSION

The experiential neuroprotective effect of capsaicin through the restoration of mitochondrial functions, antioxidant effects, and modulation of pro-inflammatory cytokines makes it a promising candidate for further drug development through clinical setup.

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.

Herbal Therapeutics for Alzheimer's Disease: Ancient Indian Medicine System from the Modern Viewpoint

Alzheimer's is a chronic neurodegenerative disease where amyloid-beta (Aβ) plaques and neurofibrillary tangles are formed inside the brain. It is also characterized by progressive memory loss, depression, neuroinflammation, and derangement of other neurotransmitters. Due to its complex etiopathology, current drugs have failed to completely cure the disease. Natural compounds have been investigated as an alternative therapy for their ability to treat Alzheimer's disease (AD). Traditional herbs and formulations which are used in the Indian ayurvedic system are rich sources of antioxidant, anti-amyloidogenic, neuroprotective, and anti-inflammatory compounds. They promote quality of life by improving cognitive memory and rejuvenating brain functioning through neurogenesis. A rich knowledge base of traditional herbal plants (Turmeric, Gingko, Ashwagandha, Shankhpushpi, Giloy, Gotu kola, Garlic, Tulsi, Ginger, and Cinnamon) combined with modern science could suggest new functional leads for Alzheimer's drug discovery. In this article Ayurveda, the ancient Indian herbal medicine system based on multiple clinical and experimental, evidence have been reviewed for treating AD and improving brain functioning. This article presents a modern perspective on the herbs available in the ancient Indian medicine system as well as their possible mechanisms of action for AD treatment. The main objective of this research is to provide a systematic review of herbal drugs that are easily accessible and effective for the treatment of AD.

High Yield Synthesis of Curcumin and Symmetric Curcuminoids: A "Click" and "Unclick" Chemistry Approach

The worldwide known and employed spice of Asian origin, turmeric, receives significant attention due to its numerous purported medicinal properties. Herein, we report an optimized synthesis of curcumin and symmetric curcuminoids of aromatic (bisdemethoxycurcumin) and heterocyclic type, with yields going from good to excellent using the cyclic difluoro-boronate derivative of acetylacetone prepared by reaction of 2,4-pentanedione with boron trifluoride in THF (ca. 95%). The subsequent cleavage of the BF₂ group is of significant importance for achieving a high overall yield in this two-step procedure. Such cleavage occurs by treatment with hydrated alumina (Al₂O₃) or silica (SiO₂) oxides, thus allowing the target heptanoids obtained in high yields as an amorphous powder to be filtered off directly from the reaction media. Furthermore, crystallization instead of chromatographic procedures provides a straightforward purification step. The ease and efficiency with which the present methodology can be applied to synthesizing the title compounds earns the terms "click" and "unclick" applied to describe particularly straightforward, efficient reactions. Furthermore, the methodology offers a simple, versatile, fast, and economical synthetic alternative for the obtention of curcumin (85% yield), bis-demethoxycurcumin (78% yield), and the symmetrical heterocyclic curcuminoids (80-92% yield), in pure form and excellent yields.

Potential implications of polyphenolic compounds in neurodegenerative diseases

Neurodegenerative diseases are common chronic diseases related to progressive damage to the nervous system. Current neurodegenerative diseases present difficulties and despite extensive research efforts to develop new disease-modifying therapies, there is still no effective treatment for halting the neurodegenerative process. Polyphenols are biologically active organic compounds abundantly found in various plants. It has been reported that plant-derived dietary polyphenols may improve some disease states and promote health. Emerging pieces of evidence indicate that polyphenols are associated with neurodegenerative diseases. This review aims to overview the potential neuroprotective roles of polyphenols in most common neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and ischemic stroke.

The protective effects of curcumin on depression: Genes, transcription factors, and microRNAs involved

BACKGROUND

We aim to identify the molecular mechanisms for curcumin's anti-depressant properties, including genes, transcription factors, and miRNAs.

METHODS

The Comparative Toxicogenomics Database, GeneMania, Metascape, MIENTURNET, and Cytoscape software were used as important data approaches in this study.

RESULTS

Curcumin may have an anti-depressant effect via the relevant genes: ADORA2A, ALB, BDNF, FGF2, GLO1, GSK3B, IL6, MIF, NOS1, PTGS2, RELN, SELP, SOD1, and NR3C1. Co-expression (50.7 %) and physical interactions (28.7 %) were the primary relationships discovered by gene network analysis. The key pathways involved in curcumin's protective function against depression were "spinal cord injury", "regulation of apoptotic signaling pathway", "positive regulation of protein phosphorylation", "folate metabolism", "neuroinflammation and glutamatergic signaling", and "inflammation response". We also observed 74 miRNAs associated with depression that are targeted by curcumin, with hsa-miR-146a-5p having the greatest expression and interaction. PLSCR1, SNAI1, ZNF267, ATF3, and GTF2B were the most important transcription factors that regulated four curcumin-targeted genes. Curcumin's physicochemical characteristics and pharmacokinetics are consistent with its antidepressant effects due to its high gastrointestinal absorption, which did not remove it from the CNS, and its ability to penetrate the blood-brain barrier. Curcumin also inhibits CYP1A9 and CYP3A4.

LIMITATIONS

A toxicogenomic design in silico was applied.

CONCLUSIONS

Our findings suggest that therapy optimization and further research into curcumin's pharmacological properties are required before it may be utilized to treat depression.

Role of Nrf2 in aging, Alzheimer's and other neurodegenerative diseases

Nuclear Factor-Erythroid Factor 2 (Nrf2) is an important transcription factor that regulates the expression of large number of genes in healthy and disease states. Nrf2 is made up of 605 amino acids and contains 7 conserved regions known as Nrf2-ECH homology domains. Nrf2 regulates the expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy and mitochondrial function in all organs of the human body, in the peripheral and central nervous systems. Mounting evidence also suggests that altered expression of Nrf2 is largely involved in aging, neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's diseases, Amyotrophic lateral sclerosis, Stroke, Multiple sclerosis and others. The purpose of this article is to detail the essential role of Nrf2 in oxidative stress, antioxidative defense, detoxification, inflammatory responses, transcription factors, proteasomal and autophagic/mitophagic degradation, and metabolism in aging and neurodegenerative diseases. This article also highlights the Nrf2 structural and functional activities in healthy and disease states, and also discusses the current status of Nrf2 research and therapeutic strategies to treat aging and neurodegenerative diseases.

Upregulation of ribosome complexes at the blood-brain barrier in Alzheimer's disease patients

The cerebrovascular-specific molecular mechanism in Alzheimer's disease (AD) was investigated by employing comprehensive and accurate quantitative proteomics. Highly purified brain capillaries were isolated from cerebral gray and white matter of four AD and three control donors, and examined by SWATH (sequential window acquisition of all theoretical fragment ion spectra) proteomics. Of the 29 ribosomal proteins that were quantified, 28 (RPLP0, RPL4, RPL6, RPL7A, RPL8, RPL10A, RPL11, RPL12, RPL14, RPL15, RPL18, RPL23, RPL27, RPL27A, RPL31, RPL35A, RPS2, RPS3, RPS3A, RPS4X, RPS7, RPS8, RPS14, RPS16, RPS20, RPS24, RPS25, and RPSA) were significantly upregulated in AD patients. This upregulation of ribosomal protein expression occurred only in brain capillaries and not in brain parenchyma. The protein expression of protein processing and N-glycosylation-related proteins in the endoplasmic reticulum (DDOST, STT3A, MOGS, GANAB, RPN1, RPN2, SEC61B, UGGT1, LMAN2, and SSR4) were also upregulated in AD brain capillaries and was correlated with the expression of ribosomal proteins. The findings reported herein indicate that the ribosome complex, the subsequent protein processing and N-glycosylation-related processes are significantly and specifically upregulated in the brain capillaries of AD patients.

Dementia Prevention in Clinical Practice

Over 55 million people globally are living with dementia and, by 2050, this number is projected to increase to 131 million. This poses immeasurable challenges for patients and their families and a significant threat to domestic and global economies. Given this public health crisis and disappointing results from disease-modifying trials, there has been a recent shift in focus toward primary and secondary prevention strategies. Approximately 40% of Alzheimer's disease (AD) cases, which is the most common form of dementia, may be prevented or at least delayed. Success of risk reduction studies through addressing modifiable risk factors, in addition to the failure of most drug trials, lends support for personalized multidomain interventions rather than a "one-size-fits-all" approach. Evolving evidence supports early intervention in at-risk patients using individualized interventions directed at modifiable risk factors. Comprehensive risk stratification can be informed by emerging principals of precision medicine, and include expanded clinical and family history, anthropometric measurements, blood biomarkers, neurocognitive evaluation, and genetic information. Risk stratification is key in differentiating subtypes of dementia and identifies targetable areas for intervention. This article reviews a clinical approach toward dementia risk stratification and evidence-based prevention strategies, with a primary focus on AD.

The Antioxidative Effects of Picein and Its Neuroprotective Potential: A Review of the Literature

Neurodegenerative diseases (NDDs) are the main cause of dementia in the elderly, having no cure to date, as the currently available therapies focus on symptom remission. Most NDDs will progress despite treatment and eventually result in the death of the patient after several years of a burden on both the patient and the caregivers. Therefore, it is necessary to investigate agents that tackle the disease pathogenesis and can efficiently slow down or halt disease progression, with the hope of curing the patients and preventing further burden and mortality. Accordingly, recent research has focused on disease-modifying treatments with neuroregenerative or neuroprotective effects. For this purpose, it is necessary to understand the pathogenesis of NDDs. It has been shown that oxidative stress plays an important role in the damage to the central nervous system and the progression of neurodegenerative disorders. Furthermore, mitochondrial dysfunction and the accumulation of unfolded proteins, including beta-amyloid (Aβ), tau proteins, and α-synuclein, have been suggested. Accordingly, cellular and molecular studies have investigated the efficacy of several natural compounds (herbs and nutritional agents) for their neuroprotective and antioxidative properties. The most popular herbs suggested for the treatment and/or prevention of NDDs include Withania somnifera (ashwagandha), ginseng, curcumin, resveratrol, Baccopa monnieri, and Ginkgo biloba. In some herbs, such as ginseng, preclinical and clinical evidence are available for supporting its effectiveness; however, in some others, only cellular and animal studies are available. In line with the scant literature in terms of the effectiveness of herbal compounds on NDDs, there are also other herbal agents that have been disregarded. Picein is one of the herbal agents that has been investigated in only a few studies. Picein is the active ingredient of several herbs and can be thus extracted from different types of herbs, which makes it more available. It has shown to have anti-inflammatory properties in cellular and plant studies; however, to date, only one study has suggested its neuroprotective properties. Furthermore, some cellular studies have shown no anti-inflammatory effect of picein. Therefore, a review of the available literature is required to summarize the results of studies on picein. To date, no review study seems to have addressed this issue. Thus, in the present study, we gather the available information about the antioxidative and potential neuroprotective properties of picein and its possible effectiveness in treating NDDs. We also summarize the plants from which picein can be extracted in order to guide researchers for future investigations.

Curcumin piperidone derivatives induce anti-proliferative and anti-migratory effects in LN-18 human glioblastoma cells

Curcumin has demonstrated potential cytotoxicity across various cell lines despite its poor bioavailability and rapid metabolism. Therefore, our group have synthesized curcuminoid analogues with piperidone derivatives, FLDP-5 and FLDP-8 to overcome these limitations. In this study, the analogues were assessed on LN-18 human glioblastoma cells in comparison to curcumin. Results from cytotoxicity assessment showed that FLDP-5 and FLDP-8 curcuminoid analogues caused death in LN-18 cells in a concentration-dependent manner after 24-h treatment with much lower IC50 values of 2.5 µM and 4 µM respectively, which were more potent compared to curcumin with IC50 of 31 µM. Moreover, a significant increase (p < 0.05) in the level of superoxide anion and hydrogen peroxide upon 2-h and 6-h treatment confirmed the oxidative stress involvement in the cell death process induced by these analogues. These analogues also showed potent anti-migratory effects through inhibition of LN-18 cells' migration and invasion. In addition, cell cycle analysis showed that these analogues are capable of inducing significant (p < 0.05) S-phase cell cycle arrest during the 24-h treatment as compared to untreated, which explained the reduced proliferation indicated by MTT assay. In conclusion, these curcuminoid analogues exhibit potent anti-cancer effects with anti-proliferative and anti-migratory properties towards LN-18 cells as compared to curcumin.