Flavonoids: Potential Candidates for the Treatment of Neurodegenerative Disorders

Exploring the neuroprotective benefits of phytochemicals extracted from indigenous edible fruits in Bangladesh

The increasing incidence of neurodegenerative diseases (NDs) and the constraints of existing treatment methods have spurred a keen interest in investigating alternative therapies. Medicinal plants, renowned for their long-standing use in traditional medicine, offer a hopeful avenue for discovering new neuroprotective agents. This study emphasizes the potential neuroprotective characteristics of edible fruit plants in Bangladesh, specifically focusing on their traditional folk medicine uses for neurological disorders. This study provides an in-depth overview of the different types of edible fruit trees in Bangladesh and their phytochemicals, including flavonoids, terpenoids, and phenolic acids. This work examines the scientific data supporting the neuroprotective properties of bioactive chemicals from plants. It further explores the mechanisms by which these compounds work to counteract oxidative stress, decrease inflammation, and stimulate neurogenesis. Moreover, the study investigates toxicological characteristics and bioactive components of some fruits, emphasizing the importance of further investigation to measure their safety profile comprehensively. This thorough study highlights the potential benefits of Bangladesh's edible fruit trees as a rich source of neuroprotective chemicals. It also shows that additional research might lead to novel approaches for improving brain functioning and preventing NDs.

A Review of the Protective Effects of Alkaloids against Alpha-synuclein Toxicity in Parkinson's Disease

BACKGROUND

Alpha-synuclein (α-syn) aggregation products may cause neural injury and several neurodegenerative disorders (NDs) known as α-synucleinopathies. Alkaloids are secondary metabolites present in a variety of plant species and may positively affect human health, particularly α-synucleinopathy-associated NDs.

AIM

To summarize the latest scientific data on the inhibitory properties of alkaloids in α- synucleinopathies, especially in Parkinson's disease.

METHODS

Literature search was performed using web-based databases including Web of Science, PubMed, and Scopus up to January 2024, in the English language.

RESULTS

Harmala alkaloids, caffein, lycorine, piperin, acetylcorynoline, berberin, papaverine, squalamine, trodusquemine and nicotin have been found to be the most active natural alkaloids against synucleinopathy. The underlying mechanisms that contribute to this effect would be the inhibition of α-syn aggregation; elimination of formed aggregates; improvement in autophagy activation; promotion of the activity and expression of antioxidative enzymes; and prevention of oxidative injury and apoptosis in dopaminergic neurons.

CONCLUSION

The findings of the present study highlight the inhibitory activities of alkaloids against synucleinopathy. However, no clinical data supports the reported activities in humans, which calls attention to the need for conducting clinical trials to elucidate the efficacy, safety, proper dosage, unwanted effects and pharmacokinetics aspects of alkaloids in humans.

Beta-site APP-cleaving Enzyme-1 Inhibitory Role of Natural Flavonoids in the Treatment of Alzheimer's Disease

Alzheimer's Disease (AD) is a devastating neurological condition characterized by a progressive decline in cognitive function, including memory loss, reasoning difficulties, and disorientation. Its hallmark features include the formation of neurofibrillary tangles and neuritic plaques in the brain, disrupting normal neuronal function. Neurofibrillary tangles, composed of phosphorylated tau protein and neuritic plaques, containing amyloid-β protein (Aβ) aggregates, contribute to the degenerative process. The discovery of the beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) in 1999 revolutionized our understanding of AD pathogenesis. BACE1 plays a crucial role in the production of Aβ, the toxic protein implicated in AD progression. Elevated levels of BACE1 have been observed in AD brains and bodily fluids, underscoring its significance in disease onset and progression. Despite setbacks in clinical trials of BACE1 inhibitors due to efficacy and safety concerns, targeting BACE1 remains a promising therapeutic strategy for early-stage AD. Natural flavonoids have emerged as potential BACE1 inhibitors, demonstrating the ability to reduce Aβ production in neuronal cells and inhibit BACE1 activity. In our review, we delve into the pathophysiology of AD, highlighting the central role of BACE1 in Aβ production and disease progression. We explore the therapeutic potential of BACE1 inhibitors, including natural flavonoids, in controlling AD symptoms. Additionally, we provide insights into ongoing clinical trials and available patents in this field, shedding light on future directions for AD treatment research.

The Effects of Fisetin and Curcumin on Oxidative Damage Caused by Transition Metals in Neurodegenerative Diseases

Neurodegenerative diseases pose a significant health challenge for the elderly. The escalating presence of toxic metals and chemicals in the environment is a potential contributor to central nervous system dysfunction and the onset of neurodegenerative conditions. Transition metals play a crucial role in various pathophysiological mechanisms associated with prevalent neurodegenerative diseases such as Alzheimer's and Parkinson's. Given the ubiquitous exposure to metals from diverse sources in everyday life, the workplace, and the environment, most of the population faces regular contact with different forms of these metals. Disturbances in the levels and homeostasis of certain transition metals are closely linked to the manifestation of neurodegenerative disorders. Oxidative damage further exacerbates the progression of neurological consequences. Presently, there exists no curative therapy for individuals afflicted by neurodegenerative diseases, with treatment approaches primarily focusing on alleviating pathological symptoms. Within the realm of biologically active compounds derived from plants, flavonoids and curcuminoids stand out for their extensively documented antioxidant, antiplatelet, and neuroprotective properties. The utilization of these compounds holds the potential to formulate highly effective therapeutic strategies for managing neurodegenerative diseases. This review provides a comprehensive overview of the impact of abnormal metal levels, particularly copper, iron, and zinc, on the initiation and progression of neurodegenerative diseases. Additionally, it aims to elucidate the potential of fisetin and curcumin to inhibit or decelerate the neurodegenerative process.

Gut-Brain Axis a Key Player to Control Gut Dysbiosis in Neurological Diseases

Parkinson's disease is a chronic neuropathy characterised by the formation of Lewy bodies (misfolded alpha-synuclein) in dopaminergic neurons of the substantia nigra and other parts of the brain. Dopaminergic neurons play a vital role in generating both motor and non-motor symptoms. Finding therapeutic targets for Parkinson's disease (PD) is hindered due to an incomplete understanding of the disease's pathophysiology. Existing evidence suggests that the gut microbiota participates in the pathogenesis of PD via immunological, neuroendocrine, and direct neural mechanisms. Gut microbial dysbiosis triggers the loss of dopaminergic neurons via mitochondrial dysfunction. Gut dysbiosis triggers bacterial overgrowth in the small intestine, which increases the permeability barrier and induces systemic inflammation. It results in excessive stimulation of the innate immune system. In addition to that, activation of enteric neurons and enteric glial cells initiates the aggregation of alpha-synuclein. This alpha-synucleinopathy thus affects all levels of the brain-gut axis, including the central, autonomic, and enteric nervous systems. Though the neurobiological signaling cascade between the gut microbiome and the central nervous system is poorly understood, gut microbial metabolites may serve as a promising therapeutic strategy for PD. This article summarises all the known possible ways of bidirectional signal communication, i.e., the "gut-brain axis," where microbes from the middle gut interact with the brain and vice versa, and highlights a unique way to treat neurodegenerative diseases by maintaining homeostasis. The tenth cranial nerve (vagus nerve) plays a significant part in this signal communication. However, the leading regulatory factor for this axis is a diet that helps with microbial colonisation and brain function. Short-chain fatty acids (SCFAs), derived from microbially fermented dietary fibres, link host nutrition to maintain intestinal homeostasis. In addition to that, probiotics modulate cognitive function and the metabolic and behavioural conditions of the body. As technology advances, new techniques will emerge to study the tie-up between gut microbes and neuronal diseases.

Chromenone: An emerging scaffold in anti-Alzheimer drug discovery

Alzheimer's disease (AD) presents a growing global health concern. In recent decades, natural and synthetic chromenone have emerged as promising drug candidates due to their multi-target potential. Natural chromenone, quercetin, scopoletin, esculetin, coumestrol, umbelliferone, bergapten, and methoxsalen (xanthotoxin), and synthetic chromenone hybrids comprising structures like acridine, 4-aminophenyl, 3-arylcoumarins, quinoline, 1,3,4-oxadiazole, 1,2,3-triazole, and tacrine, have been explored for their potential to combat AD. Key reactions used for synthesis of chromenone hybrids include Perkin and Pechmann condensation. The activity of chromenone hybrids has been reported against several drug targets, including AChE, BuChE, BACE-1, and MAO-A/B. This review comprehensively explores natural, semisynthetic, and synthetic chromenone, elucidating their synthetic routes, possible mode of action/drug targets and structure-activity relationships (SAR). The acquired knowledge provides valuable insights for the development of new chromenone hybrids against AD.

Effects of Extended Treatment with Protium heptaphyllum Liposomes on Metabolic Parameters of Obese Rats

Protium heptaphyllum (P. heptaphyllum), popularly known as "almacega" or "white pitch", is widely used in folk medicine due to its antioxidant, anti-inflammatory and healing properties, attributed to its richness in flavonoids and terpenes. Therefore, this study aimed to evaluate the effects of treatment for 28 days with liposomes containing P. heptaphyllum leaf extract in obese animals. Male Wistar rats, subjected to a hypercaloric diet for 8 weeks to induce obesity (hypercaloric chow and water enriched with 30% sucrose, ad libitum), were treated with the plant formulation (1 mg kg-1day-1, via gavage) for 28 days. The study investigated morphological, metabolic, redox state, immunological and histological parameters in adipose and liver tissue. Rats were divided into four groups: control (C), liposomes with extract (H), obese (O) and obese treated with liposomes containing extract (OH). The results indicated that the obese group (O) presented weight gain, hepatic steatosis and alterations in metabolic and inflammatory parameters. However, treatment with liposomes (OH) reduced glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatinine and the lipid profile. In adipose tissue, the OH group showed decreased superoxide dismutase (SOD) activity and increased glutathione S-transferase (GST) activity, in contrast to the effects observed in liver GST. In the analysis of thiobarbituric-acid-reactive substances (TBARS), it was possible to observe an increase in all groups in adipose tissue and in group O in liver tissue, in addition to a reduction in TBARS in group OH in the liver, indicating modulation of oxidative stress. The treatment also increased the concentration of IL-10 and IL-17 in the liver and decreased that of IL-6 in adipose tissue. After 28 days of treatment, these results point to the therapeutic potential of treatment with P. heptaphyllum, not necessarily only against obesity, but also an effect per se of the liposomes, possibly due to the high concentration of flavonoids present in the plant extract.

Study of Liposomes Containing Extract from the Leaves of Protium heptaphyllum (Aubl.) March in Animals Submitted to a Mutagenic Model Induced by Cyclophosphamide

Cyclophosphamide (CPA) is an alkylating agent used as a chemotherapy agent in the treatment of cancer, but it has immunosuppressive effects. Protium heptaphyllum (P. heptaphyllum) is a plant rich in triterpenes and flavonoids, with some bioactive and therapeutic properties presented in the literature. Thus, the present study aimed to investigate the chemoprotective potential of P. heptaphyllum extract inserted into liposomes against oxidative damage chemically induced by CPA. Male Swiss mice received 1.5 mg/kg of P. heptaphyllum liposomes as a pre-treatment for 14 consecutive days (via gavage) and 100 mg/kg of CPA in a single dose (via intraperitoneal) on the 15th day. After the experimental period, blood and organ samples were collected for histopathological and biochemical analyses, including superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione S-transferase (GST), reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), ascorbic acid (ASA), carbonyl protein, cytokine measurement, and micronucleus testing. The results showed that liposomes containing P. heptaphyllum extract have an antimutagenic effect against damage induced to DNA by CPA, and that they also protect against oxidative stress, as verified by the increase in the antioxidant enzymes SOD and GPx. The improvement in alkaline phosphatase and creatinine markers suggests a beneficial effect on the liver and kidneys, respectively. However, the depletion of GSH in the liver and brain suggests the use of antioxidants for the metabolism of molecules generated in these tissues. In general, these data show good prospects for the use of P. heptaphyllum liposomes as a cancer chemoprotective agent, as well as possible antioxidant action, conceivably attributed to the flavonoids present in the plant extract.

Naringenin mitigates nanoparticulate-aluminium induced neuronal degeneration in brain cortex and hippocampus through downregulation of oxidative stress and neuroinflammation

Alumunium usage and toxicity has been a global concern especially an increased use of nanoparticulated aluminum (Al-NPs) products from the environment and the workplace. Al degrades in to nanoparticulate form in the environment due to the routine process of bioremediation in human body. Al-NPs toxicity plays key role in the pathophysiology of neurodegeneration which is characterised by the development of neurofibrillary tangles and neuritic plaques which correlates to the Alzheimer's disease. This study evaluated the Al-NPs induced neurodegeneration and causative behavioral alterations due to oxidative stress, inflammation, DNA damage, β-amyloid aggregation, and histopathological changes in mice. Furthermore, the preventive effect of naringenin (NAR) as a potent neuroprotective flavonoid against Al-NPs induced neurodegeneration was assessed. Al-NPs were synthesized and examined using FTIR, XRD, TEM, and particle size analyzer. Mice were orally administered with Al-NPs (6 mg/kg b.w.) followed by NAR treatment (10 mg/kg b.w. per day) for 66 days. The spatial working memory was determined by novel object recognition, T-maze, Y-maze, and Morris Water Maze tests. We measured nitric oxide, advanced oxidation of protein products, protein carbonylation, lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, reduced glutathione, oxidised glutathione, and acetylcholine esterase, as well as cytokines analysis, immunohistochemistry, and DNA damage. Al-NPs significantly reduced the learning memory power, increased oxidative stress, reduced antioxidant enzymatic activity, increased DNA damage, altered the levels of cytokines, and increased β-amyloid aggregation in the cortex and hippocampus regions of the mice brain. These neurobehavioral impairments, neuronal oxidative stress, and histopathological alterations were significantly attenuated by NAR supplementation. In conclusion, Al-NPs may be potent neurotoxic upon exposure and that NAR could serve as a potential preventive measure in the treatment and management of neuronal degeneration.

Flavonoids as Potential Therapeutics Against Neurodegenerative Disorders: Unlocking the Prospects

Neurodegeneration, the decline of nerve cells in the brain, is a common feature of neurodegenerative disorders (NDDs). Oxidative stress, a key factor in NDDs such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease can lead to neuronal cell death, mitochondria impairment, excitotoxicity, and Ca2+ stress. Environmental factors compromising stress response lead to cell damage, necessitating novel therapeutics for preventing or treating brain disorders in older individuals and an aging population. Synthetic medications offer symptomatic benefits but can have adverse effects. This research explores the potential of flavonoids derived from plants in treating NDDs. Flavonoids compounds, have been studied for their potential to enter the brain and treat NDDs. These compounds have diverse biological effects and are currently being explored for their potential in the treatment of central nervous system disorders. Flavonoids have various beneficial effects, including antiviral, anti-allergic, antiplatelet, anti-inflammatory, anti-tumor, anti-apoptotic, and antioxidant properties. Their potential to alleviate symptoms of NDDs is significant.

A multitier virtual screening study of phytoconstituents as Myeloid Cell Leukemias 1 inhibitors

Myeloid Cell Leukemia 1 (MCL1) is an anti-apoptotic protein that plays a critical role in regulating cell survival, particularly in cancer cells. It is a member of the BCL-2 family of proteins, which control the intrinsic pathway of apoptosis. MCL1 has emerged as a promising target for cancer therapy because it is overexpressed in a wide range of cancers, including breast, lung, prostate, and hematologic malignancies. Due to its remarkable role in cancer progression, it has been reflected as a promising drug target for cancer therapy. A few MCL1 inhibitors have been identified previously, but further research is needed to develop novel, effective and safe MCL1 inhibitors that can overcome resistance mechanisms and minimize toxicity in normal cells. In this study, we aim to search for compounds that target the critical binding site of MCL1 from phytoconstituent library from the IMPPAT database. To accomplish this, a multitier virtual screening approach involving molecular docking and molecular dynamics simulations (MDS) were used to evaluate their suitability for the receptor. Notably, certain screened phytoconstituents have appreciable docking scores and stable interactions toward the binding pocket of MCL1. The screened compounds underwent ADMET and bioactivity analysis to establish their anticancer properties. One phytoconstituent, Isopongaflavone, was identified that exhibiting higher docking and drug-likeness than the already reported MCL1 inhibitor, Tapotoclax. Isopongaflavone and and Tapotoclax, along with MCL1, were subjected to 100 nanoseconds (ns) MDS study to verify their stability inside the binding site of MCL1. The MDS findings demonstrated a strong binding affinity between Isopongaflavone and the MCL1 binding pocket, resulting in reduced conformational fluctuations. This investigation proposes Isopongaflavone as a promising candidate for the development of innovative anticancer therapeutics, pending the necessary validation procedures. Also, the findings provide valuable information for designing MCL1 inhibitors based on the protein's structure.Communicated by Ramaswamy H. Sarma.

The zebrafish gut microbiome influences benzo[a]pyrene developmental neurobehavioral toxicity

Early-life exposure to environmental toxicants like Benzo[a]pyrene (BaP) is associated with several health consequences in vertebrates (i.e., impaired or altered neurophysiological and behavioral development). Although toxicant impacts were initially studied relative to host physiology, recent studies suggest that the gut microbiome is a possible target and/or mediator of behavioral responses to chemical exposure in organisms, via the gut-brain axis. However, the connection between BaP exposure, gut microbiota, and developmental neurotoxicity remains understudied. Using a zebrafish model, we determined whether the gut microbiome influences BaP impacts on behavior development. Embryonic zebrafish were treated with increasing concentrations of BaP and allowed to grow to the larval life stage, during which they underwent behavioral testing and intestinal dissection for gut microbiome profiling via high-throughput sequencing. We found that exposure affected larval zebrafish microbiome diversity and composition in a manner tied to behavioral development: increasing concentrations of BaP were associated with increased taxonomic diversity, exposure was associated with unweighted UniFrac distance, and microbiome diversity and exposure predicted larval behavior. Further, a gnotobiotic zebrafish experiment clarified whether microbiome presence was associated with BaP exposure response and behavioral changes. We found that gut microbiome state altered the relationship between BaP exposure concentration and behavioral response. These results support the idea that the zebrafish gut microbiome is a determinant of the developmental neurotoxicity that results from chemical exposure.

Effectiveness of Flavonoid-Rich Diet in Alleviating Symptoms of Neurodegenerative Diseases

Over the past decades, there has been a significant increase in the burden of neurological diseases, including neurodegenerative disorders, on a global scale. This is linked to a widespread demographic trend in which developed societies are aging, leading to an increased proportion of elderly individuals and, concurrently, an increase in the number of those afflicted, posing one of the main public health challenges for the coming decades. The complex pathomechanisms of neurodegenerative diseases and resulting varied symptoms, which differ depending on the disease, environment, and lifestyle of the patients, make searching for therapies for this group of disorders a formidable challenge. Currently, most neurodegenerative diseases are considered incurable. An important aspect in the fight against and prevention of neurodegenerative diseases may be broadly understood lifestyle choices, and more specifically, what we will focus on in this review, a diet. One proposal that may help in the fight against the spread of neurodegenerative diseases is a diet rich in flavonoids. Flavonoids are compounds widely found in products considered healthy, such as fruits, vegetables, and herbs. Many studies indicated not only the neuroprotective effects of these compounds but also their ability to reverse changes occurring during the progression of diseases such as Alzheimer's, Parkinson's and amyotrophic lateral sclerosis. Here, we present the main groups of flavonoids, discussing their characteristics and mechanisms of action. The most widely described mechanisms point to neuroprotective functions due to strong antioxidant and anti-inflammatory effects, accompanied with their ability to penetrate the blood-brain barrier, as well as the ability to inhibit the formation of protein aggregates. The latter feature, together with promoting removal of the aggregates is especially important in neurodegenerative diseases. We discuss a therapeutic potential of selected flavonoids in the fight against neurodegenerative diseases, based on in vitro studies, and their impact when included in the diet of animals (laboratory research) and humans (population studies). Thus, this review summarizes flavonoids' actions and impacts on neurodegenerative diseases. Therapeutic use of these compounds in the future is potentially possible but depends on overcoming key challenges such as low bioavailability, determining the therapeutic dose, and defining what a flavonoid-rich diet is and determining its potential negative effects. This review also suggests further research directions to address these challenges.

Exploring the Comprehensive Neuroprotective and Anticancer Potential of Afzelin

Neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, Huntington's disease, and others) and cancer, seemingly disparate in their etiology and manifestation, exhibit intriguing associations in certain cellular and molecular processes. Both cancer and neurodegenerative diseases involve the deregulation of cellular processes such as apoptosis, proliferation, and DNA repair and pose a significant global health challenge. Afzelin (kaempferol 3-O-rhamnoside) is a flavonoid compound abundant in various plant sources. Afzelin exhibits a diverse range of biological activities, offering promising prospects for the treatment of diseases hallmarked by oxidative stress and deregulation of cell death pathways. Its protective potential against oxidative stress is also promising for alleviating the side effects of chemotherapy. This review explores the potential therapeutic implications of afzelin, including its capacity to mitigate oxidative stress, modulate inflammation, and promote cellular regeneration in neurodegenerative and cancer diseases.

Unveiling the neuroprotective properties of isoflavones: current evidence, molecular mechanisms and future perspectives

Neurodegenerative diseases encompass a wide range of debilitating and incurable brain disorders characterized by the progressive deterioration of the nervous system's structure and function. Isoflavones, which are naturally occurring polyphenolic phytochemicals, have been found to regulate various cellular signaling pathways associated with the nervous system. The main objective of this comprehensive review is to explore the neuroprotective effects of isoflavones, elucidate the underlying mechanisms, and assess their potential for treating neurodegenerative disorders. Relevant data regarding isoflavones and their impact on neurodegenerative diseases were gathered from multiple library databases and electronic sources, including PubMed, Google Scholar, Web of Science, and Science Direct. Numerous isoflavones, including genistein, daidzein, biochanin A, and formononetin, have exhibited potent neuroprotective properties against various neurodegenerative diseases. These compounds have been found to modulate neurotransmitters, which in turn contributes to their ability to protect against neurodegeneration. Both in vitro and in vivo experimental studies have provided evidence of their neuroprotection mechanisms, which involve interactions with estrogenic receptors, antioxidant effects, anti-inflammatory properties, anti-apoptotic activity, and modulation of neural plasticity. This review aims to provide current insights into the neuroprotective characteristics of isoflavones and shed light on their potential therapeutic applications in future clinical scenarios.

Systems pharmacology and multi-scale mechanism of Enicostema axillare bioactives in treating Alzheimer disease

As a progressive neurological disease with increased morbidity and mortality, Alzheimer Disease (AD) is characterized by neuron damage that controls memory and mental functions. Enicostema axillare (EA), an herb with a history of combativeness and effectiveness in treating Rheumatoid Arthritis, Cancer, and Diabetes, is used in Indian folk medicine from a holistic point of view. Though the herb is used for many illnesses, the molecular mechanism of its bioactive on AD has not been deciphered by intricate research. A unique pharmacology approach based on ADME drug screening and targeting, pathway enrichment (GO and KEGG), and network pharmacology, was established to explore the molecular mechanisms of E. axillare (EA) bioactive compounds for the treatment of AD. In brief, we bring to light the three active compounds of EA and seven potential molecular targets of AD, which are mainly implicated in four signaling pathways, i.e., MAPK, Apoptosis, neurodegeneration, and the TNF pathway. Moreover, the network analysis of the active compounds, molecular targets, and their pathways reveals the pharmacological nature of the compounds. Further, molecular docking studies were carried out to explore the interactions between the EA bioactive compounds and the targets and examine the binding affinity. The outcome of the work reflects the potential therapeutic effects of the compounds for treating AD through the modulation of the key proteins, which further corroborates the reliability of our network pharmacology analysis. This study not only helps in understanding the molecular mechanism of the drugs but also helps in finding and sorting new drugs for the treatment of AD, and other complex diseases through modern medicine.

Neuroprotective potential of Afzelin: A novel approach for alleviating catalepsy and modulating Bcl-2 expression in Parkinson's disease therapy

The lost dopaminergic neurons in the brain prevent mobility in Parkinson's disease (PD). It is impossible to stop the disease's progress by means of symptoms management. Research focuses on oxidative stress, mitochondrial dysfunction, and neuronal degeneration. Exploration of potential neuroprotective drugs against prosurvival B-cell lymphoma 2 (Bcl-2) protein is ongoing. An investigable cause behind PD, as well as preventive measures, could be discovered considering the association between such behavioural manifestations (cataleptic behaviours) and PD. The compound Afzelin, known to guard the nervous system, was chosen for this study. The study was done on rats divided into six different groups. First, there was a control group. The other group was treated with Reserpine (RES) (1 mg/kg). The third group received RES (1 mg/kg) and levodopa (30 mg/kg). The remaining three groups were given RES (1 mg/kg) in conjunction with Afzelin at the following doses: 5 mg/kg, 10 mg/kg, and 20 mg/kg. Cataleptic behavior and mobility in rats was assessed using the rotarod, open field, and modified forced-swim tests. thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), biogenic amines, and Bcl-2 level in rat tissue homogenates were considered. According to the study's findings, the rats treated through co-administration of RES and Afzelin improved significantly in their cataleptic behaviours and locomotor activity. In addition, administering Afzelin itself caused Bcl-2 expression, which could have some neuroprotection properties. This study provides meaningful information on the effectiveness of Afzelin in handling catalepsy and other degenerative neurologic disorders. As a result, other studies need to be conducted to establish the reasons behind the reactions and determine the long-term effects of Afzelin on these conditions.

Pathogenesis of Neurodegenerative Diseases and the Protective Role of Natural Bioactive Components

Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.

Tackling Neuroinflammation in Cognitive Disorders with Single-targeted and Multi-targeted Histamine H3 Receptor Modulators

Neuroinflammation is a process involved in a variety of central nervous system (CNS) diseases and is being increasingly recognized as a key mediator of cognitive impairments. Neuroinflammatory responses including glial activation, increased production of proinflammatory cytokines, and aberrant neuronal signaling, contribute to cognitive dysfunctions. Histamine is a key peripheral inflammatory mediator, but plays an important role in neuroinflammatory processes as well. The unique localization of histamine H3 receptor (H3R) in the CNS along with the modulation of the release of other neurotransmitters via its action on heteroreceptors on non-histaminergic neurons have led to the development of several H3R ligands for various brain diseases. H3R antagonists/ inverse agonists have revealed potential to treat diverse neuroinflammatory CNS disorders, including neurodegenerative diseases, attention-deficit hyperactivity syndrome and schizophrenia. In this mini review, we provide a brief overview on the crucial involvement of the histaminergic transmission in the neuroinflammatory processes underlying these cognitive disorders, with a special focus on H3R involvement. The anti-neuroinflammatory potential of single-targeted and multi-targeted H3R antagonists/inverse agonists for the treatment of these conditions is discussed here.

Emerging Role of Plant-Based Bioactive Compounds as Therapeutics in Parkinson's Disease

Neurological ailments, including stroke, Alzheimer's disease (AD), epilepsy, Parkinson's disease (PD), and other related diseases, have affected around 1 billion people globally to date. PD stands second among the common neurodegenerative diseases caused as a result of dopaminergic neuron loss in the midbrain's substantia nigra regions. It affects cognitive and motor activities, resulting in tremors during rest, slow movement, and muscle stiffness. There are various traditional approaches for the management of PD, but they provide only symptomatic relief. Thus, a survey for finding new biomolecules or substances exhibiting the therapeutic potential to patients with PD is the main focus of present-day research. Medicinal plants, herbal formulations, and natural bioactive molecules have been gaining much more attention in recent years as synthetic molecules orchestrate a number of undesired effects. Several in vitro, in vivo, and in silico studies in the recent past have demonstrated the therapeutic potential of medicinal plants, herbal formulations, and plant-based bioactives. Among the plant-based bioactives, polyphenols, terpenes, and alkaloids are of particular interest due to their potent anti-inflammatory, antioxidant, and brain-health-promoting properties. Further, there are no concise, elaborated articles comprising updated mechanism-of-action-based reviews of the published literature on potent, recently investigated (2019-2023) medicinal plants, herbal formulations, and plant based-bioactive molecules, including polyphenols, terpenes, and alkaloids, as a method for the management of PD. Therefore, we designed the current review to provide an illustration of the efficacious role of various medicinal plants, herbal formulations, and bioactives (polyphenols, terpenes, and alkaloids) that can become potential therapeutics against PD with greater specificity, target approachability, bioavailability, and safety to the host. This information can be further utilized in the future to develop several value-added formulations and nutraceutical products to achieve the desired safety and efficacy for the management of PD.

Huntington's Disease: Understanding Its Novel Drugs and Treatments

An inherited neurodegenerative ailment called Huntington's disease (HD) of gradual physical impairment, cognitive decline, and psychiatric symptoms. It is brought on by a mutation of the HTT gene, which causes aberrant huntingtin protein buildup in neurons. This predominantly affects the striatum and cerebral cortex, where neuronal malfunction and eventual cell death follow. The quality index of life for both patients and their families is significantly impacted when symptoms first appear in mid-adulthood. An overview of the available therapies for HD is given in this article. Although HD has no known treatment options, there are several that try to lessen symptoms and reduce the disease's development. By lowering involuntary movements, pharmaceutical treatments like tetrabenazine and deutetrabenazine focus on motor symptoms. Antidepressants and antipsychotic medicines are also used to manage the mental and cognitive symptoms of HD. The investigation of prospective gene-based medicines is a result of research into disease-modifying medications. Reduced synthesis of mutant huntingtin protein is the goal of RNA interference (RNAi) strategies, which may halt the course of illness. Additionally, continuing research into Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9 (CRISPR-Cas9) and other gene editing methods shows promise for reversing the genetic mutation that causes HD. Individuals with HD can benefit from non-pharmacological therapies such as physical therapy, speech therapy, and occupational therapy to increase their functional abilities and general well-being. Supportive treatment, psychiatric therapy, and caregiver support groups are also essential in addressing the difficult problems the illness presents. In conclusion, tremendous progress is being made in the domain of HD treatment, with an emphasis on symptom control, disease modification, and prospective gene-based therapeutics. Even though there has been significant improvement, more study is still required to provide better therapies and ultimately discover a solution for this debilitating condition.

Insights into the mechanism underlying UV-B induced flavonoid metabolism in callus of a Tibetan medicinal plant Mirabilis himalaica

Mirabilis himalaica is an important Tibetan medicinal plant in China. However, it has become a rare and class I endangered Tibetan medicine plant. Therefore, the use of callus to propagate germplasm resources is of great significance. We found that the flavonoid content of M. himalaica callus increased continuously with the extension of UV-B treatment. Multi-omics profiles were used to reveal the co-expression patterns of gene networks of flavonoid metabolism in M. himalaica callus during UV-B radiation. Results showed that five medicinal metabolics, including geranin, eriodictyol, astragalin, isoquercetin, pyrotechnic acid, and one anthocyanin malvide-3-O-glucoside were identified. The transcriptome data were divided into 46 modules according to the expression pattern by WGCNA (weighted gene co-expression network analysis), of which the module Turquoise had the strongest correlation with six target metabolites. We found that seven structural genes and twenty-five transcription factors were related to the metabolism of flavonoid synthesis, among which the structural genes CHI, C4H and UGT79B6 had strong co-expression relationships with the 6 target metabolites. WRKY42, WRKY7, bHLH128 and other transcription factors had strong co-expression relationships with multiple structural genes. Consequently, these findings suggest callus grown under UV-B treatment could be an effective alternative medical resource of M. himalaica, which is valuable for conservation and usage of this wild and endangered plant.

Regulatory Roles of Flavonoids in Caspase-11 Non-Canonical Inflammasome-Mediated Inflammatory Responses and Diseases

Inflammasomes are multiprotein complexes that activate inflammatory responses by inducing pyroptosis and secretion of pro-inflammatory cytokines. Along with many previous studies on inflammatory responses and diseases induced by canonical inflammasomes, an increasing number of studies have demonstrated that non-canonical inflammasomes, such as mouse caspase-11 and human caspase-4 inflammasomes, are emerging key players in inflammatory responses and various diseases. Flavonoids are natural bioactive compounds found in plants, fruits, vegetables, and teas and have pharmacological properties in a wide range of human diseases. Many studies have successfully demonstrated that flavonoids play an anti-inflammatory role and ameliorate many inflammatory diseases by inhibiting canonical inflammasomes. Others have demonstrated the anti-inflammatory roles of flavonoids in inflammatory responses and various diseases, with a new mechanism by which flavonoids inhibit non-canonical inflammasomes. This review discusses recent studies that have investigated the anti-inflammatory roles and pharmacological properties of flavonoids in inflammatory responses and diseases induced by non-canonical inflammasomes and further provides insight into developing flavonoid-based therapeutics as potential nutraceuticals against human inflammatory diseases.

Modulating Inflammation-Mediated Diseases via Natural Phenolic Compounds Loaded in Nanocarrier Systems

The global increase and prevalence of inflammatory-mediated diseases have been a great menace to human welfare. Several works have demonstrated the anti-inflammatory potentials of natural polyphenolic compounds, including flavonoid derivatives (EGCG, rutin, apigenin, naringenin) and phenolic acids (GA, CA, etc.), among others (resveratrol, curcumin, etc.). In order to improve the stability and bioavailability of these natural polyphenolic compounds, their recent loading applications in both organic (liposomes, micelles, dendrimers, etc.) and inorganic (mesoporous silica, heavy metals, etc.) nanocarrier technologies are being employed. A great number of studies have highlighted that, apart from improving their stability and bioavailability, nanocarrier systems also enhance their target delivery, while reducing drug toxicity and adverse effects. This review article, therefore, covers the recent advances in the drug delivery of anti-inflammatory agents loaded with natural polyphenolics by the application of both organic and inorganic nanocarriers. Even though nanocarrier technology offers a variety of possible anti-inflammatory advantages to naturally occurring polyphenols, the complexes' inherent properties and mechanisms of action have not yet been fully investigated. Thus, expanding the quest on novel natural polyphenolic-loaded delivery systems, together with the optimization of complexes' activity toward inflammation, will be a new direction of future efforts.

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.

A Cocktail of Polyherbal Bioactive Compounds and Regular Mobility Training as Senolytic Approaches in Age-dependent Alzheimer's: the In Silico Analysis, Lifestyle Intervention in Old Age

Alzheimer's is a principal concern globally. Machine learning is a valuable tool to determine protective and diagnostic approaches for the elderly. We analyzed microarray datasets of Alzheimer's cases based on artificial intelligence by R statistical software. This study provided a screened pool of ncRNAs and coding RNAs related to Alzheimer's development. We designed hub genes as cut points in networks and predicted potential microRNAs and LncRNA to regulate protein networks in aging and Alzheimer's through in silico algorithms. Notably, we collected effective traditional herbal medicines. A list of bioactive compounds prepared including capsaicin, piperine, crocetin, safranal, saffron oil, coumarin, thujone, rosmarinic acid, sabinene, thymoquinone, ascorbic acid, vitamin E, cyanidin, rhaponticin, isovitexin, coumarin, nobiletin, evodiamine, gingerol, curcumin, quercetin, fisetin, and allicin as an effective fusion that potentially modulates hub proteins and molecular signaling pathways based on pharmacophore model screening and chemoinformatics survey. We identified profiles of 21 mRNAs, 272 microRNAs, and eight LncRNA in Alzheimer's based on prediction algorithms. We suggested a fusion of senolytic herbal ligands as an alternative therapy and preventive formulation in dementia. Also, we provided ncRNAs expression status as novel monitoring strategies in Alzheimer's and new cut-point proteins as novel therapeutic approaches. Synchronizing fusion drugs and lifestyle could reverse Alzheimer's hallmarks to amelioration via an offset of the signaling pathways, leading to increased life quality in the elderly.

A Potential Strategy for Treating Parkinson's Disease Through Intranasal Nanoemulsions

Intranasal delivery has great potential to cross the blood-brain barrier and deliver the drug molecule into the central nervous system faster than the traditional methods. The olfactory neuronal and trigeminal pathways both are involved in intranasal delivery. The nano-technology is an innovative strategy for the nose to brain delivery. The mucoadhesive nanoemulsion formulation is a modified technology that increases the duration of drug accumulation and provides prolonged delivery at a targeted site. The nanoemulsion formulation oil, surfactant, and co-surfactant components maintain lower surface tension and particle coalescence. The globule dimension and zeta potential are affected in brain targeting. The globule size of the innovative formulation should be < 200 nm for drug permeation because, in humans, the average axon magnitude ranges from around 100 to 700 nm. Furthermore, modified technology of nanoemulsions like nanogel and nanoemulsion in-situ gel provide a great advantage to cure neurodegenerative disorders. Therefore, focusing on the innovative pharmaceutical approaches of nanoemulsion in intranasal drug delivery, the current review provides insight into the applications of nanoemulsion in neurodegenerative disorders like Parkinson's disease, which are due to the depletion of dopamine in substania nigra resulting in cardinal motor activity bradykinesia and tremors. The review also touches upon the pathways for intranasal delivery of nanoemulsion, the pathogenesis of Parkinson's disease, and the future direction of the research on intranasal nanoemulsion.

Anti-inflammatory effects of new human histamine H3 receptor ligands with flavonoid structure on BV-2 neuroinflammation

OBJECTIVE

Microglia play an important role in the neuroinflammation developed in response to various pathologies. In this study, we examined the anti-inflammatory effect of the new human histamine H₃ receptor (H₃R) ligands with flavonoid structure in murine microglial BV-2 cells.

MATERIAL AND METHODS

The affinity of flavonoids (E243 -flavone and IIIa-IIIc-chalcones) for human H₃R was evaluated in the radioligand binding assay. The cytotoxicity on BV-2 cell viability was investigated with the MTS assay. Preliminary evaluation of anti-inflammatory properties was screened by the Griess assay in an in vitro neuroinflammation model of LPS-treated BV-2 cells. The expression and secretion of pro-inflammatory cytokines were evaluated by real-time qPCR and ELISA, respectively. The expression of microglial cell markers were determined by immunocytochemistry.

RESULTS

Chalcone derivatives showed high affinity at human H₃R with K_i values < 25 nM. At the highest nontoxic concentration (6.25 μM) compound IIIc was the most active in reducing the level of nitrite in Griess assay. Additionally, IIIc treatment attenuated inflammatory process in murine microglia cells by down-regulating pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) at both the level of mRNA and protein level. Our immunocytochemistry studies revealed expression of microglial markers (Iba1, CD68, CD206) in BV-2 cell line.

CONCLUSIONS

These results emphasize the importance of further research to accurately identify the anti-inflammatory mechanism of action of chalcones.

A Novel Huntington's Disease Assessment Platform to Support Future Drug Discovery and Development

Huntington's disease (HD) is a lethal neurodegenerative disorder without efficient therapeutic options. The inefficient translation from preclinical and clinical research into clinical use is mainly attributed to the lack of (i) understanding of disease initiation, progression, and involved molecular mechanisms; (ii) knowledge of the possible HD target space and general data awareness; (iii) detailed characterizations of available disease models; (iv) better suitable models; and (v) reliable and sensitive biomarkers. To generate robust HD-like symptoms in a mouse model, the neomycin resistance cassette was excised from zQ175 mice, generating a new line: zQ175^Δneo. We entirely describe the dynamics of behavioral, neuropathological, and immunohistological changes from 15-57 weeks of age. Specifically, zQ175^Δneo mice showed early astrogliosis from 15 weeks; growth retardation, body weight loss, and anxiety-like behaviors from 29 weeks; motor deficits and reduced muscular strength from 36 weeks; and finally slight microgliosis at 57 weeks of age. Additionally, we collected the entire bioactivity network of small-molecule HD modulators in a multitarget dataset (HD_MDS). Hereby, we uncovered 358 unique compounds addressing over 80 different pharmacological targets and pathways. Our data will support future drug discovery approaches and may serve as useful assessment platform for drug discovery and development against HD.

Nutraceuticals: A Promising Therapeutic Approach in Ophthalmology

Oxidative stress represents one of the main factors driving the pathophysiology of multiple ophthalmic conditions including presbyopia, cataracts, dry eye disease (DED), glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). Currently, different studies have demonstrated the role of orally administered nutraceuticals in these diseases. For instance, they have demonstrated to improve lens accommodation in presbyopia, reduce protein aggregation in cataracts, ameliorate tear film stability, break up time, and tear production in dry eye, and participate in the avoidance of retinal neuronal damage and a decrease in intraocular pressure in glaucoma, contribute to the delayed progression of AMD, or in the prevention or treatment of neuronal death in diabetic retinopathy. In this review, we summarized the nutraceuticals which have presented a positive impact in ocular disorders, emphasizing the clinical assays. The characteristics of the different types of nutraceuticals are specified along with the nutraceutical concentration used to achieve a therapeutic outcome in ocular diseases.

Recent approaches on Huntington's disease (Review)

Huntington's disease (HD) is a neurodegenerative disorder characterized by severe motor, cognitive and psychiatric symptoms. Patients of all ages can present with a dysfunction of the nervous system, which leads to the progressive loss of movement control and disabilities in speech, swallowing, communications, etc. The molecular basis of the disease is well-known, as HD is related to a mutated gene, a trinucleotide expansion, which encodes to the huntingtin protein. This protein is linked to neurogenesis and the loss of its function leads to neurodegenerative disorders. Although the genetic cause of the disorder has been known for decades, no effective treatment is yet available to prevent onset or to eliminate the progression of symptoms. Thus, the present review focused on the development of novel methods for the timely and accurate diagnosis of HD in an aim to aid the development of therapies which may reduce the severity of the symptoms and control their progression. The majority of the therapies include gene-silencing mechanisms of the mutated huntingtin gene aiming to suppress its expression, and the use of various substances as drugs with highly promising results. In the present review, the latest approaches on the diagnosis of HD are discussed along with the need for genetic counseling and an up-to-date presentation of the applied treatments.

Phytochemical screening and effect of Viscum album L. on monoamine oxidase A and B activity and serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonealla (Lepidoptera)

ETHNOPHARMACOLOGICAL RELEVANCE

Viscum album L. (European mistletoe), a member of the Santalaceae, is a hemiparasitic, evergreen shrub growing on deciduous and coniferous trees. In traditional and folk medicine, mistletoe was used for the treatment of central nervous system disorders such as epilepsy, hysteria, insomnia, nervous excitability, neuralgia, headache, dizziness and fatigue. However, relatively little is known of its neuropharmacological activity.

AIM OF THE STUDY

The aim of the present study was to evaluate the effect of treatment with aqueous and hydroethanolic extracts from Viscum album L. parasitizing birch, linden and pine, on MAO-A and MAO-B activity as well as serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonella (Lepidoptera) larvae.

MATERIALS AND METHODS

The phytochemical composition of the extracts was characterised using UPLC-DAD-ESI-MS/MS. To investigate the neuropharmacological activity of Viscum album L. extracts, Galleria mellonella (Lepidoptera) larvae were used as a model organism. The inhibitory potential of the extracts against MAO-A and MAO-B was determined by fluorometry. The serotonin, dopamine and serotonin receptor 5-HTR1A levels in larvae hemolymph after treatment were quantified by ELISA.

RESULTS

UPLC-DAD-ESI-MS/MS analysis allowed the identification of 88 compounds, either full or in part. Most of the characterised phytochemicals were flavonoids, hydroxycinnamic acids and lignans. Screening found that aqueous and hydroethanolic mistletoe extracts inhibited the enzymatic activity of either MAO-A or MAO-B or both. Additionally, mistletoe extract administration increased the levels of serotonin and serotonin receptor 5-HTR1A. None of the tested extracts had any significant effect on dopamine level.

CONCLUSIONS

A key novel finding was that the aqueous and hydroethanolic extracts from Viscum album L. inhibited monoamine oxidase activity and increased the levels of serotonin and serotonin receptor 5-HTR1A in Galleria mellonella (Lepidoptera) larvae. These properties may be due to the presence of phenolic constituents, particularly flavonoids. Further research based on bioassay-guided fractionation of mistletoe is needed to identify CNS-active molecules.

Flavonoids from Piper Species as Promising Antiprotozoal Agents against Giardia intestinalis. Structure-Activity Relationship and Drug-Likeness Studies

Diarrhea diseases caused by the intestinal protozoan parasite Giardia intestinalis are a major global health burden. Moreover, there is an ongoing need for novel anti-Giardia drugs due to drawbacks with currently available treatments. This paper reports on the isolation and structural elucidation of six new flavonoids (1-6), along with twenty-three known ones (7-29) from the Piper species. Their structures were established by spectroscopic and spectrometric techniques. Flavonoids were tested for in vitro antiprotozoal activity against Giardia intestinalis trophozoites. In addition, structure-activity relationship (SAR) and in silico ADME studies were performed to understand the pharmacophore and pharmacokinetic properties of these natural compounds. Eight flavonoids from this series exhibited remarkable activity in the micromolar range. Moreover, compound 4 was identified as having a 40-fold greater antiparasitic effect (IC50 61.0 nM) than the clinical reference drug, metronidazole (IC50 2.5 µM). This antiprotozoal potency was coupled with an excellent selectivity index (SI 233) on murine macrophages and in silico drug-likeness. SAR studies revealed that the substitution patterns, type of functional group, and flavonoid skeleton played an essential role in the activity. These findings highlight flavonoid 4 as a promising candidate to develop new drugs for the treatment of Giardia infections.

Flavonoids as Promising Neuroprotectants and Their Therapeutic Potential against Alzheimer’s Disease

Alzheimer's disease (AD) is one of the serious and progressive neurodegenerative disorders in the elderly worldwide. Various genetic, environmental, and lifestyle factors are associated with its pathogenesis that affect neuronal cells to degenerate over the period of time. AD is characterized by cognitive dysfunctions, behavioural disability, and psychological impairments due to the accumulation of amyloid beta (Aβ) peptides and neurofibrillary tangles (NFT). Several research reports have shown that flavonoids are the polyphenolic compounds that significantly improve cognitive functions and inhibit or delay the amyloid beta aggregation or NFT formation in AD. Current research has uncovered that dietary use of flavonoid-rich food sources essentially increases intellectual abilities and postpones or hinders the senescence cycle and related neurodegenerative problems including AD. During AD pathogenesis, multiple signalling pathways are involved and to target a single pathway may relieve the symptoms but not provides the permanent cure. Flavonoids communicate with different signalling pathways and adjust their activities, accordingly prompting valuable neuroprotective impacts. Flavonoids likewise hamper the movement of obsessive indications of neurodegenerative disorders by hindering neuronal apoptosis incited by neurotoxic substances. In this short review, we briefly discussed about the classification of flavonoids and their neuroprotective properties that could be used as a potential source for the treatment of AD. In this review, we also highlight the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.

Ethnomedicinal plants used for the treatment of neurodegenerative diseases in Himachal Pradesh, India in Western Himalaya

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants are considered as a healthcare resource and widely used by rural people in their traditional medicine system for curing neurodegenerative diseases. Neurodegenerative diseases refer to incurable and debilitating conditions that result in progressive degeneration/death of nerve cells or neurons in the human brain. This review is mainly focused on the usage of different ethnomedicinal plants in the treatment of different neurodegenerative diseases in Himachal Pradesh. Study reveals total of 73 ethnomedicinal plants, which are used for treating different neurological disorders in different areas of Himachal Pradesh. The data is compiled from the different sources that described the detailed information of plants in tabular form and highlights the significance of different phytochemicals on neuroprotective function. The present study also provides the scientific data and clinical (in-vivo and in-vitro) studies in support of ethnomedicinal use.

AIM OF THE STUDY

This review aims to provide information of ethnomedicinal plants which are used for the treatment of neurodegenerative diseases in Himachal Pradesh.

MATERIALS AND METHODS

Information on the use of ethnomedicinal plants to treat various neurological disorders has been gathered from a variety of sources, including various types of literature, books, and relevant publications in Google Scholar, Research Gate, Science Direct, Scopus, and Pub Med, among others. The collected data is tabulated, including the botanical names of plants, mode of use and the disease for which it is used for curing, etc. RESULTS: There are 73 ethnomedicinal plants that are used to cure various neurological disorders, with the most plants being used to treat epilepsy problem in Himachal Pradesh.

CONCLUSION

Numerous phytochemicals and extracts from diverse plants were found to have a protective effect against neurodegenerative diseases. Antioxidant activity is known to exist in a variety of herbal plants. The most common bioactive antioxidant chemicals having their significant impacts include flavonoids, flavones, coumarins, lignans, isoflavones, catechins, anthocyanins, and isocatechins.

Salama AA, Tadros SH, El Gedaily RA. Novel Neuroprotective Potential of Bunchosia armeniaca (Cav.) DC against Lipopolysaccharide Induced Alzheimer’s Disease in Mice

Bunchosia armeniaca (Cav.) DC (Malpighiaceae) is one of the well-known traditionally used remedies worldwide. This study aims to explore the leaves’ metabolome via Quadrupole-Time-of-Flight-Liquid-Chromatography-Mass Spectrometry and to investigate the neuroprotective effect of leaves using lipopolysaccharide (LPS) induced Alzheimer’s disease model. Mice were administered LPS (0.25 mg/kg/day; intraperitoneal) as well as methanolic extract (BME), dichloromethane (BDMF), and butanol (BBF) fractions (each 200 mg/kg/day; oral) for one week. BME and BBF improved behavioral activity on the Y maze test, decreased brain content of inflammatory markers such as nuclear factor kappa B and interleukin 1 beta, and prevented the elevation of cytochrome P450 2E1, and glial fibrillary acidic protein compared to the LPS-administered group. Histopathological examination of several brain parts confirmed the neuroprotective effect of the tested extracts. In addition, BBF exhibited higher activity in all tested in vitro antioxidant and acetylcholinesterase inhibition assays. Metabolic profiling offered tentative identification of 88 metabolites, including mainly flavonoids, phenolic acids, and coumarins. Several detected metabolites, such as quercetin, apigenin, baicalin, vitexin, and resveratrol, had previously known neuroprotective effects. The current study highlighted the possible novel potential of B. armeniaca in preventing memory impairment, possibly through its antioxidant effect and inhibition of acetylcholinesterase, inflammatory and oxidative stress mediators.

Health benefits of polyphenols: A concise review

Plants produce polyphenols, which are considered highly essential functional foods in our diet. They are classified into several groups according to their diverse chemical structures. Flavanoids, lignans, stilbenes, and phenolic acids are the four main families of polyphenols. Several in vivo and in vitro research have been conducted so far to evaluate their health consequences. Polyphenols serve a vital function in the protection of the organism from external stimuli and in eliminating reactive oxygen species (ROS), which are instigators of several illnesses. Polyphenols are present in tea, chocolate, fruits, and vegetables with the potential to positively influence human health. For instance, cocoa flavan-3-ols have been associated with a decreased risk of myocardial infarction, stroke, and diabetes. Polyphenols in the diet also help to improve lipid profiles, blood pressure, insulin resistance, and systemic inflammation. Quercetin, a flavonoid, and resveratrol, a stilbene, have been linked to improved cardiovascular health. Dietary polyphenols potential to elicit therapeutic effects might be attributed, at least in part, to a bidirectional association with the gut microbiome. This is because polyphenols are known to affect the gut microbiome composition in ways that lead to better human health. Specifically, the gut microbiome converts polyphenols into bioactive compounds that have therapeutic effects. In this review, the antioxidant, cytotoxicity, anti-inflammatory, antihypertensive, and anti-diabetic actions of polyphenols are described based on findings from in vivo and in vitro experimental trials. PRACTICAL APPLICATIONS: The non-communicable diseases (NCDs) burden has been increasing worldwide due to the sedentary lifestyle and several other factors such as smoking, junk food, etc. Scientific literature evidence supports the use of plant-based food polyphenols as therapeutic agents that could help to alleviate NCD's burden. Thus, consuming polyphenolic compounds from natural sources could be an effective solution to mitigate NCDs concerns. It is also discussed how natural antioxidants from medicinal plants might help prevent or repair damage caused by free radicals, such as oxidative stress.

Influence of Molecular Structures on Fluorescence of Flavonoids and Their Detection in Mammalian Cells

Flavonoids are being increasingly applied for the treatment of various diseases due to their anti-cancer, anti-oxidant, anti-inflammatory, and anti-viral properties. However, it is often challenging to detect their presence in cells and tissues through bioimaging, as most of them are not fluorescent or are too weak to visualize. Here, fluorescence possibilities of nine naturally occurring analogous flavonoids have been investigated through UV/visible spectroscopy, molecular structure examination, fluorescent images in mammalian cells and their statistical analysis employing aluminum chloride and diphenylboric acid 2-aminoethyl ester as fluorescence enhancers. It is found that, in order to form a stable fluorescent complex with an enhancer, flavonoids should have a keto group at C4 position and at least one -OH group at C3 or C5 position. Additionally, the presence of a double bond at C2–C3 can stabilize extended quinonoid structure at the cinnamoyl moiety, which thereby enhances the complex stability. A possible restriction to the free rotation of ring B around C1′–C2 single bond can contribute to the further enhancement of fluorescence. Thus, these findings can act as a guide for distinguishing flavonoids capable of exhibiting fluorescence from thousands of their analogues. Finally, using this technique, flavonoids are detected in neuroblastoma cells and their time course assay is conducted via fluorescence imaging. Their cellular uptake efficiency is found to be high and differential in nature and their distribution throughout the cytoplasm is clearly detected.

Exploring the Therapeutic Potential of Phytochemicals in Alzheimer’s Disease: Focus on Polyphenols and Monoterpenes

Alzheimer’s disease (AD) is a chronic, complex neurodegenerative disorder mainly characterized by the irreversible loss of memory and cognitive functions. Different hypotheses have been proposed thus far to explain the etiology of this devastating disorder, including those centered on the Amyloid-β (Aβ) peptide aggregation, Tau hyperphosphorylation, neuroinflammation and oxidative stress. Nonetheless, the therapeutic strategies conceived thus far to treat AD neurodegeneration have proven unsuccessful, probably due to the use of single-target drugs unable to arrest the progressive deterioration of brain functions. For this reason, the theoretical description of the AD etiology has recently switched from over-emphasizing a single deleterious process to considering AD neurodegeneration as the result of different pathogenic mechanisms and their interplay. Moreover, much relevance has recently been conferred to several comorbidities inducing insulin resistance and brain energy hypometabolism, including diabetes and obesity. As consequence, much interest is currently accorded in AD treatment to a multi-target approach interfering with different pathways at the same time, and to life-style interventions aimed at preventing the modifiable risk-factors strictly associated with aging. In this context, phytochemical compounds are emerging as an enormous source to draw on in the search for multi-target agents completing or assisting the traditional pharmacological medicine. Intriguingly, many plant-derived compounds have proven their efficacy in counteracting several pathogenic processes such as the Aβ aggregation, neuroinflammation, oxidative stress and insulin resistance. Many strategies have also been conceived to overcome the limitations of some promising phytochemicals related to their poor pharmacokinetic profiles, including nanotechnology and synthetic routes. Considering the emerging therapeutic potential of natural medicine, the aim of the present review is therefore to highlight the most promising phytochemical compounds belonging to two major classes, polyphenols and monoterpenes, and to report the main findings about their mechanisms of action relating to the AD pathogenesis.

Polar phenol detection in rat brain: Development and validation of a versatile UHPLC-MS method and application on the brain tissues of Corinthian currant (Vitis vinifera L.,var. Apyrena) fed rats

This study aimed to validate a rapid and selective bioanalytical method, using UHPLC-Orbitrap MS, for the determination of brain polar phenolics and to apply it in rats that orally consumed Corinthian currant for 38 days. Corinthian currant, is a dried vine fruit rich in polar phenolics that potentially penetrate the brain. During method optimization fresh and lyophilized tissues were comparatively studied along with different solid-phase extraction cartridges; satisfactory recoveries (>80%) for almost all analytes were attained using fresh tissues and Oasis® HLB cartridges. Brain regional levels in phenol concentrations were then determined; isoquercetin showed higher concentrations in frontal cortex, hippocampus and cerebellum (14.0 ± 5.5, 6.6 ± 2.0, and 2.9 ± 1.3 ng/g tissue, respectively); rutin and gallic acid in cerebellum and isorhamnetin, quercetin and rutin in hippocampus of the Corinthian currant supplemented rat group compared to the control. This is the first study investigating polar phenolics' accumulation in rat brain after Corinthian currant supplementation.

Phlomis fruticosa L. exerts in vitro antineurodegenerative and antioxidant activities and induces prooxidant effect in glioblastoma cell line

Despite the significant advances in drug development we are witnessing the inability of health systems to combat both neurodegenerative diseases and cancers, especially glioblastoma. Hence, natural products are comprehensively studied in order to provide novel therapeutic options. This study aimed to explore anti-neurodegenerative and anti-glioblastoma potential of extract of Phlomis fruticosa L. using in vitro model systems. It was found that the methanol extract of P. fruticosa was able to efficiently reduce activities of enzymes linked to neurodegenerative disease including acetylcholinesterase, butyrylcholinesterase and tyrosinase. Furthermore, P. fruticosa extract has shown excellent antioxidant potential, as evidenced by six different methods. Analysis of cytotoxic effect of P. fruticosa extract on A172 glioblastoma cell line revealed that the concentration of the extract necessary for 50 % inhibition of A172 growth (IC₅₀) was 710 μg/mL. The extract did not induce changes in proliferation and morphology of A172 glioblastoma cells. On the other side, production of ROS was increased in A172 cells treated with the extract. Observed cytotoxic effect of P. fruticosa extract might be based on increase in ROS generation upon treatment. Quantitative chemical analysis revealed the presence of twelve different polyphenols with the cis 3-O-caffeoylquinic acid being the most abundant. This study provided scientific evidence for further exploration of P. fruticosa as a promising natural anti-neurodegenerative therapeutic option.

Tomatoes: An Extensive Review of the Associated Health Impacts of Tomatoes and Factors That Can Affect Their Cultivation

Simple Summary

The research outlined in this review paper discusses potential health benefits associated with a diet enriched with tomatoes and tomato products. This includes details of previous studies investigating the anticancer properties of tomatoes, protection against cardiovascular and neurodegenerative diseases and diabetes, maintenance of a healthy gut microbiome, and improved skin health, fertility, immune response, and exercise recovery. The specific parts of a tomato fruit that contribute these health benefits are also outlined. The potential disadvantages to a tomato-rich diet are detailed, especially the consumption of supplements that contain compounds found in tomatoes, such as lycopene. This review also discusses how the cultivation of tomato plants can affect the nutritional value of the fruit harvested. Different environmental growing conditions such as light intensity, growing media, and temperature are explained in terms of the impact they have on the quality of fruit, its nutrient content, and hence the potential health benefits acquired from eating the fruit.

Abstract

This review outlines the health benefits associated with the regular consumption of tomatoes and tomato products. The first section provides a detailed account of the horticultural techniques that can impact the quality of the fruit and its nutritional properties, including water availability, light intensity, temperature, and growing media. The next section provides information on the components of tomato that are likely to contribute to its health effects. The review then details some of the health benefits associated with tomato consumption, including anticancer properties, cardiovascular and neurodegenerative diseases and skin health. This review also discusses the impact tomatoes can have on the gut microbiome and associated health benefits, including reducing the risk of inflammatory bowel diseases. Other health benefits of eating tomatoes are also discussed in relation to effects on diabetes, the immune response, exercise recovery, and fertility. Finally, this review also addresses the negative effects that can occur as a result of overconsumption of tomato products and lycopene supplements.

Radical cyclization of alkynyl aryl ketones for the synthesis of 3-seleno-substituted thiochromones and chromones

Herein we present an alternative and transition-metal-free procedure to access 3-organoselanylthiochromones and 3-organoselanylchromones from the cyclization reaction between alkynyl aryl ketones and diorganyl diselenides promoted by Oxone®.

A Double-Pronged Sword: XJB-5-131 Is a Suppressor of Somatic Instability and Toxicity in Huntington's Disease

Due to large increases in the elderly populations across the world, age-related diseases are expected to expand dramatically in the coming years. Among these, neurodegenerative diseases will be among the most devastating in terms of their emotional and economic impact on patients, their families, and associated subsidized health costs. There is no currently available cure or rescue for dying brain cells. Viable therapeutics for any of these disorders would be a breakthrough and provide relief for the large number of affected patients and their families. Neurodegeneration is accompanied by elevated oxidative damage and inflammation. While natural antioxidants have largely failed in clinical trials, preclinical phenotyping of the unnatural, mitochondrial targeted nitroxide, XJB-5-131, bodes well for further translational development in advanced animal models or in humans. Here we consider the usefulness of synthetic antioxidants for the treatment of Huntington's disease. The mitochondrial targeting properties of XJB-5-131 have great promise. It is both an electron scavenger and an antioxidant, reducing both somatic expansion and toxicity simultaneously through the same redox mechanism. By quenching reactive oxygen species, XJB-5-131 breaks the cycle between the rise in oxidative damage during disease progression and the somatic growth of the CAG repeat which depends on oxidation.

Amyotrophic Lateral Sclerosis: A Diet Review

Amyotrophic lateral sclerosis (ALS) is a fatal disease related to upper and lower motor neurons degeneration. Although the environmental and genetic causes of this disease are still unclear, some factors involved in ALS onset such as oxidative stress may be influenced by diet. A higher risk of ALS has been correlated with a high fat and glutamate intake and β-methylamino-L-alanine. On the contrary, a diet based on antioxidant and anti-inflammatory compounds, such as curcumin, creatine, coenzyme Q10, vitamin E, vitamin A, vitamin C, and phytochemicals could reduce the risk of ALS. However, data are controversial as there is a discrepancy among different studies due to a limited number of samples and the many variables that are involved. In addition, an improper diet could lead to an altered microbiota and consequently to an altered metabolism that could predispose to the ALS onset. In this review we summarized some research that involve aspects related to ALS such as the epidemiology, the diet, the eating behaviour, the microbiota, and the metabolic diseases. Further research is needed to better comprehend the role of diet and the metabolic diseases in the mechanisms leading to ALS onset and progression.

Role of Phytoconstituents as PPAR Agonists: Implications for Neurodegenerative Disorders

Peroxisome proliferator-activated receptors (PPAR-γ, PPAR-α, and PPAR-β/δ) are ligand-dependent nuclear receptors that play a critical role in the regulation of hundreds of genes through their activation. Their expression and targeted activation play an important role in the treatment of a variety of diseases, including neurodegenerative, cardiovascular, diabetes, and cancer. In recent years, several reviews have been published describing the therapeutic potential of PPAR agonists (natural or synthetic) in the disorders listed above; however, no comprehensive report defining the role of naturally derived phytoconstituents as PPAR agonists targeting neurodegenerative diseases has been published. This review will focus on the role of phytoconstituents as PPAR agonists and the relevant preclinical studies and mechanistic insights into their neuroprotective effects. Exemplary research includes flavonoids, fatty acids, cannabinoids, curcumin, genistein, capsaicin, and piperine, all of which have been shown to be PPAR agonists either directly or indirectly. Additionally, a few studies have demonstrated the use of clinical samples in in vitro investigations. The role of the fruit fly Drosophila melanogaster as a potential model for studying neurodegenerative diseases has also been highlighted.

In Vitro and In Silico Characterization of Kurarinone as a Dopamine D1A Receptor Antagonist and D2L and D4 Receptor Agonist

Alterations in the expression and/or activity of brain G-protein-coupled receptors (GPCRs) such as dopamine D₁R, D_2LR, D₃R, and D₄R, vasopressin V_1AR, and serotonin 5-HT_1AR are noted in various neurodegenerative diseases (NDDs). Since studies have indicated that flavonoids can target brain GPCRs and provide neuroprotection via inhibition of monoamine oxidases (hMAOs), our study explored the functional role of kurarinone, an abundant lavandulated flavonoid in Sophora flavescens, on dopamine receptor subtypes, V_1AR, 5-HT_1AR, and hMAOs. Radioligand binding assays revealed considerable binding of kurarinone on D₁R, D_2LR, and D₄R. Functional GPCR assays unfolded the compound's antagonist behavior on D₁R (IC₅₀ 42.1 ± 0.35 μM) and agonist effect on D_2LR and D₄R (EC₅₀ 22.4 ± 3.46 and 71.3 ± 4.94 μM, respectively). Kurarinone was found to inhibit hMAO isoenzymes in a modest and nonspecific manner. Molecular docking displayed low binding energies during the intermolecular interactions of kurarinone with the key residues of the deep orthosteric binding pocket and the extracellular loops of D₁R, D_2LR, and D₄R, validating substantial binding affinities to these prime targets. With appreciable D_2LR and D₄R agonism and D₁R antagonism, kurarinone might be a potential compound that can alleviate clinical symptoms of Parkinson's disease and other NDDs.

Anti-Oxidative, Anti-Inflammatory and Anti-Apoptotic Effects of Flavonols: Targeting Nrf2, NF-κB and p53 Pathways in Neurodegeneration

Neurodegenerative diseases are one of the leading causes of disability and death worldwide. Intracellular transduction pathways that end in the activation of specific transcription factors are highly implicated in the onset and progression of pathological changes related to neurodegeneration, of which those related to oxidative stress (OS) and neuroinflammation are particularly important. Here, we provide a brief overview of the key concepts related to OS- and neuroinflammation-mediated neuropathological changes in neurodegeneration, together with the role of transcription factors nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB). This review is focused on the transcription factor p53 that coordinates the cellular response to diverse genotoxic stimuli, determining neuronal death or survival. As current pharmacological options in the treatment of neurodegenerative disease are only symptomatic, many research efforts are aimed at uncovering efficient disease-modifying agents. Natural polyphenolic compounds demonstrate powerful anti-oxidative, anti-inflammatory and anti-apoptotic effects, partially acting as modulators of signaling pathways. Herein, we review the current understanding of the therapeutic potential and limitations of flavonols in neuroprotection, with emphasis on their anti-oxidative, anti-inflammatory and anti-apoptotic effects along the Nrf2, NF-κB and p53 pathways. A better understanding of cellular and molecular mechanisms of their action may pave the way toward new treatments.