Mitigating effect of chrysin loaded solid lipid nanoparticles against Amyloid β25-35 induced oxidative stress in rat hippocampal region: An efficient formulation approach for Alzheimer's disease

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.

Development of nanomedicines for the treatment of Alzheimer's disease: Raison d'être, strategies, challenges and regulatory aspects

Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive loss of memory. Presently, AD is challenging to treat with current drug therapy as their delivery to the brain is restricted by the presence of the blood-brain barrier. Nanomedicines, due to their size, high surface volume ratio, and ease of tailoring drug release characteristics, showed their potential to treat AD. The nanotechnology-based formulations for brain targeting are expected to enter the market in the near future. So, regulatory frameworks are required to ensure the quality, safety, and effectiveness of the nanomedicines to treat AD. In this review, we discuss different strategies, in-vitro blood-brain permeation models, in-vivo permeation assessment, and regulatory aspects for the development of nanomedicine to treat AD.

An Update on the Application of Nano Phytomedicine as an Emerging Therapeutic Tool for Neurodegenerative Diseases

Abstract:

The existence of the blood-brain barrier (BBB), a densely woven network of blood vessels and endothelial cells designed to prevent the infiltration of foreign substances into the brain, the methods employed in developing treatments for neurodegenerative disorders (NDs) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Multiple sclerosis, Amyotrophic lateral sclerosis, and others, pose significant challenges and complexities. These illnesses have had a terrible impact on the human population's health. Because early detection of these problems is poor and no good therapy has been established, they have emerged as the biggest lifethreatening healthcare burden worldwide compared to other significant illnesses. Traditional drug delivery techniques do not offer efficient treatment for NDs due to constraints in the BBB design, efflux pumps, and metabolic enzyme expression. Nanotechnology has the potential to significantly enhance ND therapy by utilizing systems that have been bioengineered to engage with living organisms at the cellular range. Compared to traditional techniques, nanotechnological technologies have several potential ways for crossing the BBB and increasing therapeutic efficacy in the brain. The introduction and growth of nanotechnology indicate promising potential for overcoming this issue. Engineered nanoparticles coupled with therapeutic moieties and imaging agents with dimensions ranging from 1-100 nm can improve effectiveness, cellular uptake, selective transport, and drug delivery to the brain due to their changed physicochemical properties. Conjugates of nanoparticles and medicinal plants, or their constituents known as nano phytomedicine, have recently gained importance in developing cutting-edge neuro-therapeutics due to their abundant natural supply, promising targeted delivery to the brain, and lower potential for adverse effects. This study summarizes the common NDs, their prevalence and pathogenesis, and potential herbal nanoformulation for treating NDs.

Mechanistic insights into the potential role of dietary polyphenols and their nanoformulation in the management of Alzheimer's disease

Alzheimer's disease (AD) is a very common neurodegenerative disorder associated with memory loss and a progressive decline in cognitive activity. The two major pathophysiological factors responsible for AD are amyloid plaques (comprising amyloid-beta aggregates) and neurofibrillary tangles (consisting of hyperphosphorylated tau protein). Polyphenols, a class of naturally occurring compounds, are immensely beneficial for the treatment or management of various disorders and illnesses. Naturally occurring sources of polyphenols include plants and plant-based foods, such as fruits, herbs, tea, vegetables, coffee, red wine, and dark chocolate. Polyphenols have unique properties, such as being the major source of anti-oxidants and possessing anti-aging and anti-cancerous properties. Currently, dietary polyphenols have become a potential therapeutic approach for the management of AD, depending on various research findings. Dietary polyphenols can be an effective strategy to tackle multifactorial events that occur with AD. For instance, naturally occurring polyphenols have been reported to exhibit neuroprotection by modulating the Aβ biogenesis pathway in AD. Many nanoformulations have been established to enhance the bioavailability of polyphenols, with nanonization being the most promising. This review comprehensively provides mechanistic insights into the neuroprotective potential of dietary polyphenols in treating AD. It also reviews the usability of dietary polyphenol as nanoformulation for AD treatment.

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

Possible mechanisms involved in the neuroprotective effects of chrysin against mild traumatic brain injury-induced spatial cognitive decline: An in vivo study in a rat model

Traumatic brain injury (TBI) is recognized as an important risk factor for cognitive deficits. The present study was designed to determine the potential neuroprotective effects of chrysin, a natural flavonoid compound, against TBI-induced spatial cognitive decline and the possible mechanisms involved. Oral administration of chrysin (25, 50, or 100 mg/kg/day) was initiated in rats immediately following the induction of the diffuse TBI model using the weight-dropping Marmarou model. Spatial cognitive ability, hippocampal synaptic plasticity, blood-brain barrier (BBB) permeability, brain water content, and histological changes were assessed at scheduled time points. The animals subjected to TBI exhibited spatial cognitive decline in the Morris water maze (MWM) test, which was accompanied by inhibition of hippocampal long-term potentiation (LTP) induction at the perforant path-dentate gyrus (PP-DG) synapses. Additionally, TBI caused BBB disruption, brain edema, and neuronal loss. Interestingly, treatment with chrysin (especially in the dose of 100 mg/kg) alleviated all the above-mentioned neuropathological changes related to TBI. The results provide evidence that chrysin improves TBI-induced spatial cognitive decline, which may be partly related to the amelioration of hippocampal synaptic dysfunction, alleviation of BBB disruption, reduction of brain edema, and prevention of neuronal loss.

FGF-18 alleviates memory impairments and neuropathological changes in a rat model of Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial pathology marked by amyloid beta (Aβ) accumulation, tau hyperphosphorylation, and progressive cognitive decline. Previous studies show that fibroblast growth factor 18 (FGF18) exerts a neuroprotective effect in experimental models of neurodegeneration; however, how it affects AD pathology remains unknown. This study aimed to ascertain the impact of FGF18 on the behavioral and neuropathological changes in the rat model of sporadic AD induced by intracerebroventricular (ICV) injection of streptozotocin (STZ). The rats were treated with FGF18 (0.94 and 1.88 pmol, ICV) on the 15th day after STZ injection. Their cognitive function was assessed in the Morris water maze and passive avoidance tests for 5 days from the 16th to the 21st days. Aβ levels and histological signs of neurotoxicity were detected using the enzyme-linked immunosorbent assay (ELISA) assay and histopathological analysis of the brain, respectively. FGF18 mildly ameliorated the STZ-induced cognitive impairment; the Aβ accumulation was reduced; and the neuronal damage including pyknosis and apoptosis was alleviated in the rat brain. This study highlights the promising therapeutic potential for FGF18 in managing AD.

Recent progress of nanomedicine in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of memory disruption in elderly subjects, with the prevalence continuing to rise mainly because of the aging world population. Unfortunately, no efficient therapy is currently available for the AD treatment, due to low drug potency and several challenges to delivery, including low bioavailability and the impediments of the blood-brain barrier. Recently, nanomedicine has gained considerable attention among researchers all over the world and shown promising developments in AD treatment. A wide range of nano-carriers, such as polymer nanoparticles, liposomes, solid lipid nanoparticles, dendritic nanoparticles, biomimetic nanoparticles, magnetic nanoparticles, etc., have been adapted to develop successful new treatment strategies. This review comprehensively summarizes the recent advances of different nanomedicine for their efficacy in pre-clinical studies. Finally, some insights and future research directions are proposed. This review can provide useful information to guide the future design and evaluation of nanomedicine in AD treatment.

Applications of Nanoparticles in Alzheimer's Disease

With the rapid aging of the global population, the prevalence of neurodegenerative diseases has become a significant concern, with Alzheimer's disease (AD) being the most common. However, the clinical trials of many drugs targeting AD have failed due to the challenges posed by the blood-brain barrier (BBB), which makes intracerebral administration of drugs difficult. However, nanoparticles (NPs) may aid in the delivery of such drugs. NPs are materials with sizes between 1-100 nm that offer several advantages, such as improving biocompatibility, prolonging half-life, transporting large molecules, crossing the BBB to deliver to the central nervous system, and exhibiting good targeting ability. In addition to drug delivery, NPs also have excellent diagnostic potential, and multifunctional NPs can integrate the advantages of diagnosis, targeting, and treatment. This mini-review article provides an overview of NPs, including the composition of the carrier, strategies for crossing the BBB, and different targets of AD pathology, with the aim of providing guidance for the development prospects of NPs.

Design and evaluation of chrysin-loaded nanoemulsion against lithium/pilocarpine-induced status epilepticus in rats; emphasis on formulation, neuronal excitotoxicity, oxidative stress, microglia polarization, and AMPK/SIRT-1/PGC-1α pathway

OBJECTIVES

The present study aims to formulate and evaluate the efficacy of chrysin-loaded nanoemulsion (CH NE) against lithium/pilocarpine-induced epilepsy in rats, as well as, elucidate its effect on main epilepsy pathogenesis cornerstones; neuronal hyperactivity, oxidative stress, and neuroinflammation.

METHODS

NEs were characterized by droplet size, zeta potential, pH, in vitro release, accelerated and long-term stability studies. Anti-convulsant efficacy of the optimized formula and underlying mechanisms involved were assessed and compared to that from CH suspension given orally at a 30 folds higher dose.

RESULTS

Optimized formula displayed a droplet size of 48.09 ± 0.83 nm, PDI 0.25 ± 0.011, sustained release, and good stability. CH treatment reduced seizures scoring, corrected behavioral and histological changes induced by Li/Pilo. Moreover, CH restored neurotransmitters balance and oxidative stress markers levels. Besides, CH induced microglia polarization from M1 to M2 hindering inflammation induced by Li/Pilo. Also, CH restored energy metabolism homeostasis via regulating protein expression of AMPK/SIRT-1/PGC-1α pathway markers. CH NE formulation was found to significantly enhance drug delivery to rats' hippocampus compared to CH suspension.

CONCLUSION

Our findings prove the therapeutic efficacy of CH NE at a lower dose which could be a potential brain targeting platform to combat epilepsy.

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

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

Protective Effects of Flavonoids against Alzheimer's Disease: Pathological Hypothesis, Potential Targets, and Structure-Activity Relationship

Alzheimer’s disease (AD) is a neurodegenerative disease with high morbidity and mortality, for which there is no available cure. Currently, it is generally believed that AD is a disease caused by multiple factors, such as amyloid-beta accumulation, tau protein hyperphosphorylation, oxidative stress, and inflammation. Multitarget prevention and treatment strategies for AD are recommended. Interestingly, naturally occurring dietary flavonoids, a class of polyphenols, have been reported to have multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this review, we summarize and discuss the existing multiple pathogenic factors of AD. Moreover, we further elaborate on the biological activities of natural flavonoids and their potential mode of action and targets in managing AD by presenting a wide range of experimental evidence. The gathered data indicate that flavonoids can be regarded as prophylactics to slow the advancement of AD or avert its onset. Different flavonoids have different activities and varying levels of activity. Further, this review summarizes the structure–activity relationship of flavonoids based on the existing literature and can provide guidance on the design and selection of flavonoids as anti-AD drugs.

Flavonoids: Food associations, therapeutic mechanisms, metabolism and nanoformulations

Flavonoids possess an impressive therapeutic potential, thereby imparting them a nutraceutical character. As it becomes increasingly common to consume foods associated with healing properties, it is imperative to understand the associations of different foods with different classes of nutraceutic compounds, and their mechanisms of therapeutic action. At the same time, it is important to address the limitations thereof so that plausible future directions may be drawn. This review summarizes the food associations of flavonoids, and discusses the mechanisms responsible for imparting them their nutraceutic properties, detailing the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, inhibition of inflammatory signaling pathways such as toll-like receptor (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), cyclooxygenase 2 (COX-2) and lipoxygenase-2 (LOX-2) mediators. Further on, the review explains the mechanism of flavonoids metabolism, reasons for low bioavailability and thereafter recapitulates the role of technological interventions to overcome the limitations, with a particular focus on nanoformulations that utilize the synergy between flavonoids and biocompatible materials used as nanocarriers, as reported in works spanning over a decade. It is the Generally Recognized as Safe (GRAS) classified carriers that will become the basis for developing functional formulations. It is promisingly noteworthy that some flavonoid formulations have been commercialized and mentioned therein. Such commercially viable and safe for consumption technological applications pave way for bringing science to the table, and add value to the innate properties of flavonoids.

Neuroprotective properties of chrysin on decreases of cell proliferation, immature neurons and neuronal cell survival in the hippocampal dentate gyrus associated with cognition induced by methotrexate

Methotrexate (MTX) is a drug widely used for chemotherapy and can reduce cancer cell production by inhibiting dihydrofolate reductase and decreasing cancer cell growth. MTX has a neurotoxic effect on neural stem and glial cells, leading to memory deficits. Chrysin is a natural flavonoid that contains essential biological activities, such as neuroprotective and cognitive-improving properties. Therefore, the aim of the present study was to investigate the protective effect of chrysin against MTX-induced memory impairments related to hippocampal neurogenesis. Seventy-two male Sprague Dawley rats were divided into six groups: control, MTX, chrysin (10 and 30 mg/kg), and MTX+ chrysin (10 and 30 mg/kg) groups. Chrysin (10 and 30 mg/kg) was administered by oral gavage for 15 days. MTX (75 mg/kg) was administered by intravenous injection on days 8 and 15. Spatial and recognition memories were evaluated using the novel object location (NOL) and novel object recognition (NOR) tests, respectively. Moreover, cell proliferation, neuronal cell survival, and immature neurons in the subgranular zone of the hippocampal dentate gyrus were quantified by Ki-67, bromodeoxyuridine/neuronal nuclear protein (BrdU/NeuN), and doublecortin (DCX) immunohistochemistry staining. The results of the MTX group demonstrated that spatial and recognition memories were both impaired. Furthermore, cell division reduction, neuronal cell survival reduction, and immature neuron decreases were detected in the MTX group and not observed in the co-administration groups. Therefore, these results revealed that chrysin could alleviate memory and neurogenesis impairments in MTX-treated rats.

Tau-aggregation inhibition: promising role of nanoencapsulated dietary molecules in the management of Alzheimer's disease

Alzheimer's disease (AD) is a cumulative form of dementia associated with memory loss, cognition impairment, and finally leading to death. AD is characterized by abnormal deposits of extracellular beta-amyloid and intracellular Tau-protein tangles throughout the brain. During pathological conditions of AD, Tau protein undergoes various modifications and aggregates over time. A number of clinical trials on patients with AD symptoms have indicated the effectiveness of Tau-based therapies over anti-Aβ treatments. Thus, there is a huge paradigm shift toward Tau aggregation inhibitors. Several bioactives of plants and microbes have been suggested to cross the neuronal cell membrane and play a crucial role in managing neurodegenerative disorders. Bioactives mainly act as active modulators of AD pathology besides having antioxidant and anti-inflammatory potential. Studies also demonstrated the potential role of dietary molecules in inhibiting the formation of Tau aggregates and removing toxic Tau. Further, these molecules in nonencapsulated form exert enhanced Tau aggregation inhibition activity both in in vitro and in vivo studies suggesting a remarkable role of nanoencapsulation in AD management. The present article aims to review and discuss the structure-function relationship of Tau protein, the post-translational modifications that aid Tau aggregation and potential bioactives that inhibit Tau aggregation.

Therapeutic nanotechnologies for Alzheimer's disease: a critical analysis of recent trends and findings

Alzheimer's Disease (AD) is an irreversible neurodegenerative disease for which no disease modifying therapies are presently available. Besides the identification of pathological targets, AD presents numerous clinical and pharmacological challenges such as efficient active delivery to the central nervous system, cell targeting, and long-term dosing. Nanoparticles have been explored to overcome some of these challenges as drug delivery vehicles or drugs themselves. However, early promises have failed to materialize as no nanotechnology-based product has been able to reach the market and very few have moved past preclinical stages. In this review, we perform a critical analysis of the past decade's research on nanomedicine-based therapies for AD at the preclinical and clinical stages. The main obstacles to nanotechnology products and the most promising approaches were also identified, including renewed promise with gene editing, gene modulation, and vaccines.

Chrysin-Loaded Chitosan Nanoparticle-Mediated Neuroprotection in Aβ1-42-Induced Neurodegenerative Conditions in Zebrafish

Amyloid β plaques and neurofibrillary tangles are the characteristic features of Alzheimer's disease (AD). Plaques of amyloid β play a pivotal role in affecting cognitive functions and memory. Alzheimer's disease is a progressive neurodegenerative disease and is one of the leading causes of dementia worldwide. Several treatment strategies focusing on the amyloid cascade have been implemented to treat AD. The blood-brain barrier (BBB) poses the main obstructive barrier by refraining drugs from penetrating the brain. Nanotechnology is a promising research field for brain drug delivery using nanosized particles. Zebrafish is emerging as a model of interest to elaborate on brain targeting and nanotechnology-based therapeutics for neurodegenerative diseases. In the current study, we have synthesized and characterized chrysin-loaded chitosan nanoparticles (Chr-Chi NPs) and evaluated them for neuroprotection against amyloid-β-induced toxicity. We find that treatment with Chr-Chi NPs helps to retain memory, cognition, and synaptic connections, which are otherwise compromised due to Aβ_1-42 toxicity. The NPs further help in reducing aggregates of amyloid β, thus decreasing neuronal death and generation of reactive oxygen species (ROS). Taken together, our study brings to light a novel strategy for treating AD by a combined action on the neurons and amyloid aggregates mediated by chrysin and chitosan, respectively. Chr-Chi NPs, therefore, have the potential to provide a beneficial combinatorial treatment strategy for AD.

Osteoprotective effects of flavonoids: Evidence from in vivo and in vitro studies (Review)

Osteoporosis is a systemic bone disease characterized by decreased bone mass and quality and bone micro‑architecture degradation. Its primary cause is disorder of bone metabolism: Over‑formation of osteoclasts, resulting in increased bone resorption and insufficient osteogenesis. Traditional herbal flavonoids can be used as alternative drugs to prevent and treat osteoporosis due to their wide range of sources, structural diversity and less adverse effects. The present paper reviewed six flavonoids, including quercetin, icariin, hesperitin, naringin, chrysin and pueraria, that promote bone formation and have been widely studied in the literature over the past five years, with the aim of providing novel ideas for the development of drugs for bone‑associated disease.

Neuroprotective Potential of Chrysin: Mechanistic Insights and Therapeutic Potential for Neurological Disorders

Chrysin, a herbal bioactive molecule, exerts a plethora of pharmacological effects, including anti-oxidant, anti-inflammatory, neuroprotective, and anti-cancer. A growing body of evidence has highlighted the emerging role of chrysin in a variety of neurological disorders, including Alzheimer's and Parkinson's disease, epilepsy, multiple sclerosis, ischemic stroke, traumatic brain injury, and brain tumors. Based on the results of recent pre-clinical studies and evidence from studies in humans, this review is focused on the molecular mechanisms underlying the neuroprotective effects of chrysin in different neurological diseases. In addition, the potential challenges, and opportunities of chrysin's inclusion in the neurotherapeutics repertoire are critically discussed.

Emerging Novel Approaches for the Enhanced Delivery of Natural Products for the Management of Neurodegenerative Diseases

Neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease, Huntington disease, amyotrophic lateral sclerosis, and prion disease affect any part of the brain. The complete mechanism of ND is unknown, but there are some molecular mechanism and chemical process. Natural compounds have better compatibility with the human body along with lesser side effects. Moreover, several studies showed that various natural compounds have significant neuroprotective, potent antioxidant, and anti-inflammatory properties, which are effective for treating the different type of ND. In ND, natural compounds act by various mechanisms such as preventing the generation of reactive oxygen species (ROS), eliminating destructed biomolecules before their accumulation affects cell metabolism, and improving the disease conditions. But due to the presence of the blood-brain barrier (BBB) layer and unfavorable pharmacokinetic properties of natural compounds, their delivery into the brain is limited. To minimize this problem and enhance drug delivery into the brain with an effective therapeutic dose, there is a need to develop a practical novel approach. The various studies showed that nanoformulations and microneedles (MN) containing natural compounds such as quercetin, curcumin, resveratrol, chrysin, piperine, ferulic acid, huperzine A, berberine, baicalein, hesperetin, and retinoic acid effectively improved many ND. In this review, the effect of such natural drug-loaded nanoformulation and MN patches on ND management is discussed, along with their merits and demerits. This review aims to introduce different novel approaches for enhancing natural drug delivery into the brain to manage various neurodegenerative diseases.

A comprehensive review on medicinal herbs and novel formulations for the prevention of Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases reported in the aging population across the globe. About 46.8 million people are reported to have dementia, and AD is mainly responsible for dementia in aged people. Alzheimer's disease (AD) is thought to occur due to the accumulation of β-amyloid (Aβ) in the neocortex portion of the brain, nitric oxide mediated dysfunctioning of blood-brain barrier, reduced activity of serine racemase enzyme, cell cycle disturbances, damage of N-methyl-D-aspartate (NMDA) receptors and glutamatergic neurotransmission. Modern treatment methods target the pathways responsible for the disease. To date, solely symptomatic treatments exist for this disease, all making an attempt to counterbalance the neurotransmitter disturbance. Treatments able to prevent or at least effectively modifying the course of AD, referred to as 'disease-modifying' drugs, are still under extensive research. Effective treatments entail a better indulgence of the herbal bioactives by novel drug delivery systems. The herbal bioactive administered by novel drug delivery systems have proved beneficial in treating this disease. This review provides detailed information about the role of medicinal plants and their formulations in treating Alzheimer disease which will be highly beneficial for the researchers working in this area.

Nose-to-brain delivery of chrysin transfersomal and composite vesicles in doxorubicin-induced cognitive impairment in rats: Insights on formulation, oxidative stress and TLR4/NF-kB/NLRP3 pathways

Many cancer survivors suffer from chemotherapy-induced cognitive impairment known as 'Chemobrain'. Doxorubicin -topoisomerase II inhibitor- is widely used in breast cancer, hematological cancers and other neoplasms. However, it is reported to precipitate cognitive impairment in cancer patients via inducing oxidative stress and inflammatory response. Chrysin -5,7 dihydroxyflavone- has promising antioxidant, anti-inflammatory and anticancer properties, but suffers low bioavailability owing to its poor solubility and extensive metabolism. In the present study, chrysin was successfully formulated as transfersomal lipid vesicles and chitosan composite vesicles (CCV) exhibiting a nanometric size range, high drug entrapment efficiency, and controlled release over a 72h period. Intranasal administration of optimized chrysin formulations at a reduced dose of 0.5 mg/kg improved doxorubicin-induced memory impairment in rats evidenced by behavioral testing, inhibition of acetylcholinesterase activity and oxidative stress markers; catalase, reduced glutathione, lipid peroxidation and hydrogen peroxide. This could reduce caspase-3 expression inhibiting apoptosis. Moreover, chrysin formulations were able to inhibit doxorubicin-induced Tol-like receptor 4 (TLR4) and p65 subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) protein expression which in turn, reduced procaspase-1, Cysteinyl Aspartate Protease-1 (caspase-1) and Interleukin-1β (IL-1β) protein expression via inhibiting Nod-like receptor pyrin containing 3 (NLRP3) inflammasome. Collectively, our findings suggest the enhanced therapeutic potential of chrysin when formulated as transfersomes and CCV against chemotherapy-induced chemobrain via hindering acetylcholinesterase, oxidative stress and TLR4-NF-kB(p65)-NLRP3 pathways.

Effects of an Oroxylum indicum Extract (Sabroxy®) on Cognitive Function in Adults With Self-reported Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Study

Background: Oroxylum indicum has been used in traditional Ayurvedic medicine for the prevention and treatment of several diseases and may have neuroprotective effects.

Purpose: Examine the effects of Oroxylum indicum on cognitive function in older adults with self-reported cognitive complaints.

Study Design: Two-arm, parallel-group, 12-week, randomized, double-blind, placebo-controlled trial.

Methods: Eighty-two volunteers received either 500 mg, twice daily of a standardized Oroxylum indicum extract or placebo. Outcome measures included several computer-based cognitive tasks, the Control, Autonomy, Self-Realization, and Pleasure scale (CASP-19), Cognitive Failures Questionnaire (CFQ), and the Montreal Cognitive Assessment (MoCA). Changes in the concentration of brain-derived neurotrophic factor (BDNF) were also examined.

Results: Compared to the placebo, Oroxylum indicum was associated with greater improvements in episodic memory, and on several computer-based cognitive tasks such as immediate word recall and numeric working memory, and a faster rate of learning on the location learning task. However, there were no other significant differences in performance on the other assessed cognitive tests, the MoCA total score, or other self-report questionnaires. BDNF concentrations increased significantly in both groups, with no statistically-significant between-group differences. Oroxylum indicum was well tolerated except for an increased tendency for mild digestive complaints and headaches.

Conclusion: The results of this first human trial on the cognitive-enhancing effects of Oroxylum indicum suggest that it is a promising herbal candidate for the improvement of cognitive function in older adults with self-reported cognitive complaints.

Nanotheranostic agents for neurodegenerative diseases

Neurodegenerative diseases (NDDs), including Alzheimer's disease (AD) and Parkinson's disease (PD), affect the ageing population worldwide and while severely impairing the quality of life of millions, they also cause a massive economic burden to countries with progressively ageing populations. Parallel with the search for biomarkers for early detection and prediction, the pursuit for therapeutic approaches has become growingly intensive in recent years. Various prospective therapeutic approaches have been explored with an emphasis on early prevention and protection, including, but not limited to, gene therapy, stem cell therapy, immunotherapy and radiotherapy. Many pharmacological interventions have proved to be promising novel avenues, but successful applications are often hampered by the poor delivery of the therapeutics across the blood-brain-barrier (BBB). To overcome this challenge, nanoparticle (NP)-mediated drug delivery has been considered as a promising option, as NP-based drug delivery systems can be functionalized to target specific cell surface receptors and to achieve controlled and long-term release of therapeutics to the target tissue. The usefulness of NPs for loading and delivering of drugs has been extensively studied in the context of NDDs, and their biological efficacy has been demonstrated in numerous preclinical animal models. Efforts have also been made towards the development of NPs which can be used for targeting the BBB and various cell types in the brain. The main focus of this review is to briefly discuss the advantages of functionalized NPs as promising theranostic agents for the diagnosis and therapy of NDDs. We also summarize the results of diverse studies that specifically investigated the usage of different NPs for the treatment of NDDs, with a specific emphasis on AD and PD, and the associated pathophysiological changes. Finally, we offer perspectives on the existing challenges of using NPs as theranostic agents and possible futuristic approaches to improve them.

Thioredoxin-interacting protein (TXNIP) as a target for Alzheimer's disease: flavonoids and phenols

Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid plaques and tangles that have become the fifth leading cause of death worldwide. Previous studies have found that thioredoxin interacting protein (TXNIP) expression was increased during the development of AD neurons. TXNIP separates from the TXNIP-thioredoxin complex, and the TXNIP-NLRP3 complex assembles ASC and pro-caspase-1 to form the NLRP3 inflammasome, which triggers AD inflammation and apoptosis. CB-dock was used to explore whether 21 natural flavonoids and phenols target TXNIP based on references. Docking results showed that rutin, puerarin, baicalin, luteolin and quercetin are the most potent TXNIP inhibitors, and among them, rutin as the most effective flavonoid. And rosmarinic acid is the most potent TXNIP inhibitor of phenols. These phytochemicals could be helpful to find the lead compounds in designing and developing novel agents for Alzheimer's disease.

An updated review on the versatile role of chrysin in neurological diseases: Chemistry, pharmacology, and drug delivery approaches

Neurological diseases are responsible for a large number of morbidities and mortalities in the world. Flavonoids are phytochemicals that possess various health-promoting impacts. Chrysin, a natural flavonoid isolated from diverse fruits, vegetables, and even mushrooms, has several pharmacological activities comprising antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. The current study was designed to review the relationship between chrysin administration and neurological complications by discussing the feasible mechanism and signaling pathways. Herein, we mentioned the sources, pharmacological properties, chemistry, and drug delivery systems associated with chrysin pharmacotherapy. The role of chrysin was discussed in depression, anxiety, neuroinflammation, Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, cerebral ischemia, spinal cord injury, neuropathy, Multiple Sclerosis, and Guillain-Barré Syndrome. The findings indicate that chrysin has protective effects against neurological conditions by modulating oxidative stress, inflammation, and apoptosis in animal models. However, more studies should be done to clear the neuroprotective effects of chrysin.

Computational Drug Repurposing for Alzheimer's Disease Using Risk Genes From GWAS and Single-Cell RNA Sequencing Studies

Background: Traditional therapeutics targeting Alzheimer's disease (AD)-related subpathologies have so far proved ineffective. Drug repurposing, a more effective strategy that aims to find new indications for existing drugs against other diseases, offers benefits in AD drug development. In this study, we aim to identify potential anti-AD agents through enrichment analysis of drug-induced transcriptional profiles of pathways based on AD-associated risk genes identified from genome-wide association analyses (GWAS) and single-cell transcriptomic studies. Methods: We systematically constructed four gene lists (972 risk genes) from GWAS and single-cell transcriptomic studies and performed functional and genes overlap analyses in Enrichr tool. We then used a comprehensive drug repurposing tool Gene2Drug by combining drug-induced transcriptional responses with the associated pathways to compute candidate drugs from each gene list. Prioritized potential candidates (eight drugs) were further assessed with literature review. Results: The genomic-based gene lists contain late-onset AD associated genes (BIN1, ABCA7, APOE, CLU, and PICALM) and clinical AD drug targets (TREM2, CD33, CHRNA2, PRSS8, ACE, TKT, APP, and GABRA1). Our analysis identified eight AD candidate drugs (ellipticine, alsterpaullone, tomelukast, ginkgolide A, chrysin, ouabain, sulindac sulfide and lorglumide), four of which (alsterpaullone, ginkgolide A, chrysin and ouabain) have shown repurposing potential for AD validated by their preclinical evidence and moderate toxicity profiles from literature. These support the value of pathway-based prioritization based on the disease risk genes from GWAS and scRNA-seq data analysis. Conclusion: Our analysis strategy identified some potential drug candidates for AD. Although the drugs still need further experimental validation, the approach may be applied to repurpose drugs for other neurological disorders using their genomic information identified from large-scale genomic studies.

Structured edible lipid-based particle systems for oral drug-delivery

Oral administration is the most popular and patient-compliant route for drug delivery, though it raises great challenges due to the involvement of the gastro-intestine (GI) system and the drug bioavailability. Drug bioavailability is directly related to its ability to dissolve, transport and/or absorb through the physiological environment. A great number of drugs are characterized with low water solubility due to their hydrophobic nature, thus limiting their oral bioavailability and clinical use. Therefore, new strategies aiming to provide a protective shell through the GI system and improve drug solubility and permeability in the intestine were developed to overcome this limitation. Lipid-based systems have been proposed as good candidates for such a task owing to their hydrophobic nature which allows high drug loading, drug micellization ability during intestinal digestion due to the lipid content, and the vehicle physical protective environment. The use of edible lipids with high biocompatibility paves the bench-to-bedside translation. Four main types of structured lipid-based drug delivery systems differing in the physical state of the lipid phase have been described in the literature, namely emulsions, solid lipid nanoparticles, nanostructured lipid carriers, and oleogel-based particles. The current review provides a comprehensive overview of the different structured edible lipid-based oral delivery systems investigated up to date and emphasizes the contribution of each system component to the delivery performance, and the oral delivery path of lipids.

Alzheimer's disease: An evolving understanding of noradrenergic involvement and the promising future of electroceutical therapies

Alzheimer's disease (AD) poses a significant global health concern over the next several decades. Multiple hypotheses have been put forth that attempt to explain the underlying pathophysiology of AD. Many of these are briefly reviewed here, but to-date no disease-altering therapy has been achieved. Despite this, recent work expanding on the role of noradrenergic system dysfunction in both the pathogenesis and symptomatic exacerbation of AD has shown promise. The role norepinephrine (NE) plays in AD remains complicated but pre-tangle tau has consistently been shown to arise in the locus coeruleus (LC) of patients with AD decades before symptom onset. The current research reviewed here indicates NE can facilitate neuroprotective and memory-enhancing effects through β adrenergic receptors, while α2A adrenergic receptors may exacerbate amyloid toxicity through a contribution to tau hyperphosphorylation. AD appears to involve a disruption in the balance between these two receptors and their various subtypes. There is also a poorly characterized interplay between the noradrenergic and cholinergic systems. LC deterioration leads to maladaptation in the remaining LC-NE system and subsequently inhibits cholinergic neuron function, eventually leading to the classic cholinergic disruption seen in AD. Understanding AD as a dysfunctional noradrenergic system, provides new avenues for the use of advanced neural stimulation techniques to both study and therapeutically target the earliest stages of neuropathology. Direct LC stimulation and non-invasive vagus nerve stimulation (VNS) have both demonstrated potential use as AD therapeutics. Significant work remains, though, to better understand the role of the noradrenergic system in AD and how electroceuticals can provide disease-altering treatments.

Potential Role of Nanoparticles in Treating the Accumulation of Amyloid-Beta Peptide in Alzheimer's Patients

The disorder of Alzheimer's is marked by progressive pathophysiological neurodegeneration. The amino acid peptides in the amyloid plaques found in the brains of people with Alzheimer's disease (AD) are known as amyloid-beta (Aβ). Current treatments are not curative, and the effects associated with AD are reduced. Improving treatment results involved the targeting of drugs at optimum therapeutic concentration. Nanotechnology is seen as an unconventional, modern technology that plays a key role in the treatment of Alzheimer's disease. Using nanoparticles, molecular detection, effective drug targeting, and their combination offer high sensitivity. The aim of this review is to shed light on the function and successful role of nanoparticles to resolve Aβ aggregation and thus to help cure Alzheimer's disease. The analysis divides these nanoparticles into three categories: polymer, lipid, and gold nanoparticles. A thorough comparison was then made between the nanoparticles, which are used according to their role, properties, and size in the procedure. The nanoparticles can prevent the accumulation of Aβ during the efficient delivery of the drug to the cells to treat Alzheimer's disease. Furthermore, this comparison demonstrated the ability of these nanoparticles to deal efficiently with Alzheimer's disease. The role of these nanoparticles varied from delivering the drug to brain cells to dealing with the disease-causing peptide.

Flavonoid-Based Nanomedicines in Alzheimer's Disease Therapeutics: Promises Made, a Long Way To Go

Alzheimer's disease (AD) is characterized by the continuous decline of the cognitive abilities manifested due to the accumulation of large aggregates of amyloid-beta 42 (Aβ42), the formation of neurofibrillary tangles of hyper-phosphorylated forms of microtubule-associated tau protein, which may lead to many alterations at the cellular and systemic level. The current therapeutic strategies primarily focus on alleviating pathological symptoms rather than providing a possible cure. AD is one of the highly studied but least understood neurological problems and remains an unresolved condition of human brain degeneration. Over the years, multiple naturally derived small molecules, including plant products, microbial isolates, and some metabolic byproducts, have been projected as supplements reducing the risk or possible treatment of the disease. However, unfortunately, none has met the expected success. One major challenge for most medications is their ability to cross the blood-brain barrier (BBB). In past decades, nanotechnology-based interventions have offered an alternative platform to address the problem of the successful delivery of the drugs to the specific targets. Interestingly, the exciting interface of natural products and nanomedicine is delivering promising results in AD treatment. The potential applications of flavonoids, the plant-derived compounds best known for their antioxidant activities, and their amalgamation with nanomedicinal approaches may lead to highly effective therapeutic strategies for treating well-known neurodegenerative diseases. In the present review, we explore the possibilities and recent developments on an exciting combination of flavonoids and nanoparticles in AD.

In vitro and in vivo models for anti-amyloidosis nanomedicines

Amyloid diseases are global epidemics characterized by the accumulative deposits of cross-beta amyloid fibrils and plaques. Despite decades of intensive research, few solutions are available for the diagnosis, treatment, and prevention of these debilitating diseases. Since the early work on the interaction of human β₂-microglobulin and nanoparticles by Linse et al. in 2007, the field of amyloidosis inhibition has gradually evolved into a new frontier in nanomedicine offering numerous interdisciplinary research opportunities, especially for materials, chemistry and biophysics. In this review we summarise, for the first time, the in vitro and in vivo models employed thus far in the field of anti-amyloidosis nanomedicines. Based on this systematic summary, we bring forth the notion that, due to the complex and often overlapping physiopathologies of amyloid diseases, there is a crucial need for the appropriate use of in vitro and in vivo models for validating novel anti-amyloidosis nanomedicines, and there is a crucial need for the development of new animal models that reflect the behavioural, symptomatic and cross-talk hallmarks of amyloid diseases such as Alzheimer's (AD), Parkinson's (PD) diseases and type 2 diabetes (T2DM).

Role of Flavonoids in Neurodegenerative Diseases: Limitations and Future Perspectives

BACKGROUND

Flavonoids, a group of natural dietary polyphenols, are known for their beneficial effects on human health. By virtue of their various pharmacological effects, like anti-oxidative, antiinflammatory, anti-carcinogenic and neuroprotective effects, flavonoids have now become an important component of herbal supplements, pharmaceuticals, medicinals and cosmetics. There has been enormous literature supporting neuroprotective effect of flavonoids. Recently their efficacy in various neurodegenerative diseases, like Alzheimer's disease and Parkinson diseases, has received particular attention.

OBJECTIVE

The mechanism of flavanoids neuroprotection might include antioxidant, antiapoptotic, antineuroinflammatory and modulation of various cellular and intracellular targets. In in-vivo systems, before reaching to brain, they have to cross barriers like extensive first pass metabolism, intestinal barrier and ultimately blood brain barrier. Different flavonoids have varied pharmacokinetic characteristics, which affect their pharmacodynamic profile. Therefore, brain accessibility of flavonoids is still debatable.

METHODS

This review emphasized on current trends of research and development on flavonoids, especially in neurodegenerative diseases, possible challenges and strategies to encounter using novel drug delivery system.

RESULTS

Various flavonoids have elicited their therapeutic potential against neurodegenerative diseases, however by using nanotechnology and novel drug delivery systems, the bioavailability of favonoids could be enhanced.

CONCLUSION

This study bridges a significant opinion on medicinal chemistry, ethanopharmacology and new drug delivery research regarding use of flavonoids in management of neurodegeneration.

Therapeutic Strategies and Nano-Drug Delivery Applications in Management of Aging Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder in which the death of brain cells causes memory loss and cognitive decline. Existing drugs only suppress symptoms or delay further deterioration but do not address the cause of the disease. In spite of screening numerous drug candidates against various molecular targets of AD, only a few candidates, such as acetylcholinesterase inhibitors, are currently utilized as an effective clinical therapy. Currently, nano-based therapies can make a difference, providing new therapeutic options by helping drugs to cross the blood-brain barrier and enter the brain more effectively. The main aim of this review was to highlight advances in research on the development of nano-based therapeutics for improved treatment of AD.

Chrysin loaded lipid-core nanocapsules ameliorates neurobehavioral alterations induced by β-amyloid1-42 in aged female mice

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a clinically and progressive loss of cognitive function, neuropsychiatric and behavioral disorders. Some studies showed that chrysin has antioxidant and anti-inflammatory properties. However, your bioavailability is relatively low. Therefore, the present study was designed to investigate the effects of chrysin loaded lipid-core nanocapsules (LNCs) on neurochemical and behavioral changes in a model of AD induced by β-amyloid_1-42 (Aβ_1-42) peptide in aged female mice. For this purpose, aged female mice received free chrysin (FC) (5 mg/kg, per oral, p.o.) or chrysin loaded LNCs (C1-LNC and C5-LNC) (1 or 5 mg/kg, p.o.) for 14 days after Aβ_1-42 administration (400 pmol, i.c.v.). Aβ_1-42 induced significant impairments on memory and learning (morris water maze task, object recognition and step-down-type passive avoidance), also caused oxidative stress, reduced the levels of brain-derived neurotrophic factor (BDNF), increased neuroinflammation in prefrontal cortex and hippocampus of aged animals. Thus, C1-LNC and C5-LNC displayed significant effect against Aβ₁_-₄_2, via attenuation of oxidative stress and neuroinflammation, modulation of neurochemical and behavioral changes in a model of AD. These results point to chrysin loaded LNCs (mainly C5-LNC) can be a promising biomedical tool and a new therapeutic approach for treatment and prevention of AD.

Nanoformulations of Herbal Extracts in Treatment of Neurodegenerative Disorders

Nanotechnology is one of the methods that influenced human life in different ways and is a substantial approach that assists to overcome the multiple limitations of various diseases, particularly neurodegenerative disorders (NDs). Diverse nanostructures such as polymer nanoparticles, lipid nanoparticles, nanoliposomes, nano-micelles, and carbon nanotubes (CNTs); as well as different vehicle systems including poly lactic-co-glycolic acid, lactoferrin, and polybutylcyanoacrylate could significantly increase the effectiveness, reduce the side effects, enhance the stability, and improve the pharmacokinetics of many drugs. NDs belong to a group of annoying and debilitating diseases that involve millions of people worldwide. Previous studies revealed that several nanoformulations from a number of natural products such as curcumin (Cur), quercetin (QC), resveratrol (RSV), piperine (PIP), Ginkgo biloba, and Nigella sativa significantly improved the condition of patients diagnosed with NDs. Drug delivery to the central nervous system (CNS) has several limitations, in which the blood brain barrier (BBB) is the main drawback for treatment of NDs. This review discusses the effects of herbal-based nanoformulations, their advantages and disadvantages, to manage NDs. In summary, we conclude that herbal-based nano systems have promising proficiency in treatment of NDs, either alone or in combination with other drugs.

Chrysin: Pharmacological and therapeutic properties

Chrysin is a promising phytochemical that is categorized under the class of flavonoids based on its chemical structure. Naturally, it is widely present in propolis, honey, passion fruit, and even in mushrooms and other plant sources, whereas its synthetic counterparts are also being employed for pharmacological purposes. It has widely been employed in treatment of various degenerative disorders and provides cytotoxic and anti-inflammatory functions. Its antioxidant and disease preventing abilities are attributed to its structural diversity arising in ring-A and absence of oxygenation in B and C ring. In this review, the scientific studies are being reported emphasizing benefits and its allied health claims on chrysin in numerous metabolic malfunctions.

A window into the brain: Tools to assess pre-clinical efficacy of biomaterials-based therapies on central nervous system disorders

Therapeutic conveyance into the brain is a cardinal requirement for treatment of diverse central nervous system (CNS) disorders and associated pathophysiology. Effectual shielding of the brain by the blood-brain barrier (BBB) sieves out major proportion of therapeutics with the exception of small lipophilic molecules. Various nano-delivery systems (NDS) provide an effective solution around this obstacle owing to their small size and targeting properties. To date, these systems have been used for several pre-clinical disease models including glioma, neurodegenerative diseases and psychotic disorders. An efficacy screen for these systems involves a test battery designed to probe into the multiple facets of therapeutic delivery. Despite their wide application in redressing various disease targets, the efficacy evaluation strategies for all can be broadly grouped into four modalities, namely: histological, bio-imaging, molecular and behavioural. This review presents a comprehensive insight into all of these modalities along with their strengths and weaknesses as well as perspectives on an ideal design for a panel of tests to screen brain nano-delivery systems.

Neurotheranostics as personalized medicines

The discipline of neurotheranostics was forged to improve diagnostic and therapeutic clinical outcomes for neurological disorders. Research was facilitated, in largest measure, by the creation of pharmacologically effective multimodal pharmaceutical formulations. Deployment of neurotheranostic agents could revolutionize staging and improve nervous system disease therapeutic outcomes. However, obstacles in formulation design, drug loading and payload delivery still remain. These will certainly be aided by multidisciplinary basic research and clinical teams with pharmacology, nanotechnology, neuroscience and pharmaceutic expertise. When successful the end results will provide "optimal" therapeutic delivery platforms. The current report reviews an extensive body of knowledge of the natural history, epidemiology, pathogenesis and therapeutics of neurologic disease with an eye on how, when and under what circumstances neurotheranostics will soon be used as personalized medicines for a broad range of neurodegenerative, neuroinflammatory and neuroinfectious diseases.

Therapeutic effects of chrysin in a rat model of traumatic brain injury: A behavioral, biochemical, and histological study

AIMS

Oxidative stress and apoptosis have major roles in the progression of traumatic brain injury (TBI)-associated motor and cognitive deficits. The present study was aimed to elucidate the putative effects of chrysin, a natural flavonoid compound, against TBI-induced motor and cognitive dysfunctions and possible involved mechanisms.

MAIN METHODS

Chrysin (25, 50 or 100 mg/kg) was orally administered to rats starting immediately following TBI induction by Marmarou's weight-drop technique and continuously for 3 or 14 days. Neurological functions, motor coordination, learning and memory performances, histological changes, cell apoptosis, expression of pro- and anti-apoptotic proteins, and oxidative status were assayed at scheduled time points after experimental TBI.

KEY FINDINGS

The results indicated that treatment with chrysin improved learning and memory disabilities in passive avoidance task, and ameliorated motor coordination impairment in rotarod test after TBI. These beneficial effects were accompanied by increased the concentrations of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), decreased malondialdehyde (MDA) content, prevented neuronal loss, diminished apoptotic index, elevated the expression of anti-apoptotic Bcl-2 protein, and reduced the expression of pro-apoptotic Bax protein in the cerebral cortex and hippocampus tissues.

SIGNIFICANCE

Our findings suggest that both anti-oxidative and anti-apoptotic properties of chrysin (especially in the dose of 100 mg/kg) are possible mechanisms that improve cognitive/motor deficits and prevent neuronal cell death after TBI.

Design and Synthesis of CNS-targeted Flavones and Analogues with Neuroprotective Potential Against H2O2- and Aβ1-42-Induced Toxicity in SH-SY5Y Human Neuroblastoma Cells

With the lack of available drugs able to prevent the progression of Alzheimer’s disease (AD), the discovery of new neuroprotective treatments able to rescue neurons from cell injury is presently a matter of extreme importance and urgency. Here, we were inspired by the widely reported potential of natural flavonoids to build a library of novel flavones, chromen-4-ones and their C-glucosyl derivatives, and to explore their ability as neuroprotective agents with suitable pharmacokinetic profiles. All compounds were firstly evaluated in a parallel artificial membrane permeability assay (PAMPA) to assess their effective permeability across biological membranes, namely the blood-brain barrier (BBB). With this test, we aimed not only at assessing if our candidates would be well-distributed, but also at rationalizing the influence of the sugar moiety on the physicochemical properties. To complement our analysis, logD_7.4 was determined. From all screened compounds, the p-morpholinyl flavones stood out for their ability to fully rescue SH-SY5Y human neuroblastoma cells against both H₂O₂- and Aβ_1-42-induced cell death. Cholinesterase inhibition was also evaluated, and modest inhibitory activities were found. This work highlights the potential of C-glucosylflavones as neuroprotective agents, and presents the p-morpholinyl C-glucosylflavone 37, which did not show any cytotoxicity towards HepG2 and Caco-2 cells at 100 μM, as a new lead structure for further development against AD.