Resveratrol Brain Delivery for Neurological Disorders Prevention and Treatment

Coconut oil-based resveratrol nanoemulsion: Optimization using response surface methodology, stability assessment and pharmacokinetic evaluation

Phytochemicals are widely studied for therapeutic applications and nanostructured delivery systems for phytochemicals are under spotlight. Resveratrol is a promising candidate for neurodegenerative disorders. In the present study, we aimed to formulate nanoemulsion of resveratrol by ultrasonication process using response surface methodology. The effect of both formulation and ultrasonication process factors were studied for the nanoemulsification process using coconut oil, Pluronic-P107, and Cremophor EL. The time, intensity, and power of ultrasonication were selected as process factors. The globule size, PDI, and zeta potential were the responses selected. The concentrations of oil and surfactant and the intensity were found to significantly influence the globule size. The concentration of resveratrol in the optimized nanoemulsion formulation was 2.6442 mg/ml. The in vitro drug release in pH 6.8 phosphate buffer as well as in vitro permeation study on goat nasal mucosa proved the superiority of the nanoemulsion formulation. On intranasal administration in the rat at a resveratrol dose of 2 mg/kg, the brain targeting efficacy of the nanoemulsion formulation was high. Overall, this research provides the benefit of intake of resveratrol containing fruits and, its incorporation into nanoemulsions system could be a promising alternative for the management of Alzheimer's disease.

Liposomes: Novel Drug Delivery Approach for Targeting Parkinson's Disease

Parkinson's disease is one of the most severe progressive neurodegenerative disorders, having a mortifying effect on the health of millions of people around the globe. The neural cells producing dopamine in the substantia nigra of the brain die out. This leads to symptoms like hypokinesia, rigidity, bradykinesia, and rest tremor. Parkinsonism cannot be cured, but the symptoms can be reduced with the intervention of medicinal drugs, surgical treatments, and physical therapies. Delivering drugs to the brain for treating Parkinson's disease is very challenging. The blood-brain barrier acts as a highly selective semi-permeable barrier, which refrains the drug from reaching the brain. Conventional drug delivery systems used for Parkinson's disease do not readily cross the blood barrier and further lead to several side-effects. Recent advancements in drug delivery technologies have facilitated drug delivery to the brain without flooding the bloodstream and by directly targeting the neurons. In the era of Nanotherapeutics, liposomes are an efficient drug delivery option for brain targeting. Liposomes facilitate the passage of drugs across the blood-brain barrier, enhances the efficacy of the drugs, and minimize the side effects related to it. The review aims at providing a broad updated view of the liposomes, which can be used for targeting Parkinson's disease.

Role of natural products for the treatment of Alzheimer's disease

Negative psychological and physiological consequences of neurodegenerative disorders represent a high social and health cost. Among the neurodegenerative disorders Alzheimer's disease (AD) is recognized as a leading neurodegenerative condition and a primary cause of dementia in the elderlys. AD is considered as neurodegenerative disorder that progressively impairs cognitive function and memory. According to current epidemiological data, about 50 milLion people worldwide are suffering from AD. The primary symptoms of AD are almost inappreciable and usually comprise forgetfulness of recent events. Numerous processes are involved in the development of AD, for example oxidative stress (OS) mainly due to mitochondrial dysfunction, intracellular the accumulation of hyperphosphorylated tau (τ) proteins in the form of neurofibrillary tangles, excessive the accumulation of extracellular plaques of beta-amyloid (Aβ), genetic and environmental factors. Running treatments only attenuate symptoms and temporarily reduce the rate of cognitive progression associated with AD. This means that most treatments focus only on controlLing symptoms, particularly in the initial stages of the disease. In the past, the first choice of treatment was based on natural ingredients. In this sense, diverse natural products (NPs) are capable to decrease the symptoms and alleviate the development of several diseases including AD attracting the attention of the scientific community and the pharmaceutical industry. Specifically, numerous NPs including flavonoids, gingerols, tannins, anthocyanins, triterpenes and alkaloids have been shown anti-inflammatory, antioxidant, anti-amyloidogenic, and anti-choLinesterase properties. This review provide a summary of the pathogenesis and the therapeutic goals of AD. It also discusses the available data on various plants and isolated natural compounds used to prevent and diminish the symptoms of AD.

Natural Products Targeting Amyloid Beta in Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by severe brain damage and dementia. There are currently few therapeutics to treat this disease, and they can only temporarily alleviate some of the symptoms. The pathogenesis of AD is mainly preceded by accumulation of abnormal amyloid beta (Aβ) aggregates, which are toxic to neurons. Therefore, modulation of the formation of these abnormal aggregates is strongly suggested as the most effective approach to treat AD. In particular, numerous studies on natural products associated with AD, aiming to downregulate Aβ peptides and suppress the formation of abnormal Aβ aggregates, thus reducing neural cell death, are being conducted. Generation of Aβ peptides can be prevented by targeting the secretases involved in Aβ-peptide formation (secretase-dependent). Additionally, blocking the intra- and intermolecular interactions of Aβ peptides can induce conformational changes in abnormal Aβ aggregates, whereby the toxicity can be ameliorated (structure-dependent). In this review, AD-associated natural products which can reduce the accumulation of Aβ peptides via secretase- or structure-dependent pathways, and the current clinical trial states of these products are discussed.

Dysregulation of PGC-1α-Dependent Transcriptional Programs in Neurological and Developmental Disorders: Therapeutic Challenges and Opportunities

Substantial evidence indicates that mitochondrial impairment contributes to neuronal dysfunction and vulnerability in disease states, leading investigators to propose that the enhancement of mitochondrial function should be considered a strategy for neuroprotection. However, multiple attempts to improve mitochondrial function have failed to impact disease progression, suggesting that the biology underlying the normal regulation of mitochondrial pathways in neurons, and its dysfunction in disease, is more complex than initially thought. Here, we present the proteins and associated pathways involved in the transcriptional regulation of nuclear-encoded genes for mitochondrial function, with a focus on the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α). We highlight PGC-1α’s roles in neuronal and non-neuronal cell types and discuss evidence for the dysregulation of PGC-1α-dependent pathways in Huntington’s Disease, Parkinson’s Disease, and developmental disorders, emphasizing the relationship between disease-specific cellular vulnerability and cell-type-specific patterns of PGC-1α expression. Finally, we discuss the challenges inherent to therapeutic targeting of PGC-1α-related transcriptional programs, considering the roles for neuron-enriched transcriptional coactivators in co-regulating mitochondrial and synaptic genes. This information will provide novel insights into the unique aspects of transcriptional regulation of mitochondrial function in neurons and the opportunities for therapeutic targeting of transcriptional pathways for neuroprotection.

Dysregulation of PGC-1α-Dependent Transcriptional Programs in Neurological and Developmental Disorders: Therapeutic Challenges and Opportunities

Substantial evidence indicates that mitochondrial impairment contributes to neuronal dysfunction and vulnerability in disease states, leading investigators to propose that the enhancement of mitochondrial function should be considered a strategy for neuroprotection. However, multiple attempts to improve mitochondrial function have failed to impact disease progression, suggesting that the biology underlying the normal regulation of mitochondrial pathways in neurons, and its dysfunction in disease, is more complex than initially thought. Here, we present the proteins and associated pathways involved in the transcriptional regulation of nuclear-encoded genes for mitochondrial function, with a focus on the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α). We highlight PGC-1α's roles in neuronal and non-neuronal cell types and discuss evidence for the dysregulation of PGC-1α-dependent pathways in Huntington's Disease, Parkinson's Disease, and developmental disorders, emphasizing the relationship between disease-specific cellular vulnerability and cell-type-specific patterns of PGC-1α expression. Finally, we discuss the challenges inherent to therapeutic targeting of PGC-1α-related transcriptional programs, considering the roles for neuron-enriched transcriptional coactivators in co-regulating mitochondrial and synaptic genes. This information will provide novel insights into the unique aspects of transcriptional regulation of mitochondrial function in neurons and the opportunities for therapeutic targeting of transcriptional pathways for neuroprotection.

The Role of Natural Antioxidants in the Prevention of Dementia-Where Do We Stand and Future Perspectives

Dementia, and especially Alzheimer's disease (AD), puts significant burden on global healthcare expenditure through its increasing prevalence. Research has convincingly demonstrated the implication of oxidative stress in the pathogenesis of dementia as well as of the conditions which increase the risk of developing dementia. However, drugs which target single pathways have so far failed in providing significant neuroprotection. Natural antioxidants, due to their effects in multiple pathways through which oxidative stress leads to neurodegeneration and triggers neuroinflammation, could prove valuable weapons in our fight against dementia. Although efficient in vitro and in animal models of AD, natural antioxidants in human trials have many drawbacks related to the limited bioavailability, unknown optimal dose, or proper timing of the treatment. Nonetheless, trials evaluating several of these natural compounds are ongoing, as are attempts to modify these compounds to achieve improved bioavailability.

Effects of melatonin and resveratrol on recognition memory and passive avoidance performance in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is the foremost cause of dementia among other neurodegenerative diseases, leading to memory loss and cognitive deficits. AD has gained extensive attention in research for exploring possible interventions. One promising field is natural substances and compounds that could provide a wide range of neuroprotection against AD. This study aimed to investigate the possible effects of melatonin (MEL) and resveratrol (RES) in improving memory deficits in a sporadic mouse model of AD. Memory deficit was induced using AlCl₃ and d-galactose for generating an AD mouse model. Mice were randomly distributed into five groups (n = 13): control, AD, AD + MEL (AD mice treated with 80 mg/kg of MEL), AD + RES (AD mice treated with 40 mg/kg of RES), and AD + Combination)AD mice that received 80 mg/kg MEL and 40 mg/kg RES). A novel object recognition task (NORT) and passive avoidance task (PAT) were used for assessing memory. Moreover, acetylcholinesterase (AChE) level, brain-derived neurotrophic factor (BDNF), and cAMP-response element binding (CREB) protein expression were measured in the prefrontal cortex tissue. Our results showed that MEL significantly improved memory deficits in both the NORT and PAT of the AD model, while RES improved the PAT only in the AD model. Co-treatment with MEL and RES exerted beneficial additive effects on recognition memory impairment in the AD mouse model. Moreover, our results demonstrated that both MEL and RES enhanced the cholinergic system and BDNF and CREB signaling pathways in the prefrontal cortex in an AD mouse model.

Plant Natural Compounds in the Treatment of Adrenocortical Tumors

Plant natural products are a plethora of diverse and complex molecules produced by the plant secondary metabolism. Among these, many can reserve beneficial or curative properties when employed to treat human diseases. Even in cancer, they can be successfully used and indeed numerous phytochemicals exert antineoplastic activity. The most common molecules derived from plants and used in the fight against cancer are polyphenols, i.e., quercetin, genistein, resveratrol, curcumin, etc. Despite valuable data especially in preclinical models on such compounds, few of them are currently used in the medical practice. Also, in adrenocortical tumors (ACT), phytochemicals are scarcely or not at all used. This work summarizes the available research on phytochemicals used against ACT and adrenocortical cancer, a very rare disease with poor prognosis and high metastatic potential, and wants to contribute to stimulate preclinical and clinical research to find new therapeutic strategies among the overabundance of biomolecules produced by the plant kingdom.

Nanotechnology to improve the Alzheimer's disease therapy with natural compounds

Alzheimer's disease (AD) is a form of dementia with high impact worldwide, accounting with more than 46 million cases. It is estimated that the number of patients will be four times higher in 2050. The initial symptoms of AD are almost imperceptible and typically involve lapses of memory in recent events. However, the available medicines still focus on controlling the symptoms and do not cure the disease. Regarding the advances in the discovery of new treatments for this devastating disease, natural compounds are gaining increasing relevance in the treatment of AD. Nevertheless, they present some limiting characteristics such as the low bioavailability and the low ability to cross the blood-brain barrier (BBB) that hinder the development of effective therapies. To overcome these issues, the delivery of natural products by targeting nanocarriers has aroused a great interest, improving the therapeutic activity of these molecules. In this article, a review of the research progress on drug delivery systems (DDS) to improve the therapeutic activity of natural compounds with neuroprotective effects for AD is presented. Graphical abstract.

Nose-to-brain Delivery of Natural Compounds for the Treatment of Central Nervous System Disorders

BACKGROUND

Several natural compounds have demonstrated potential for the treatment of central nervous system disorders such as ischemic cerebrovascular disease, glioblastoma, neuropathic pain, neurodegenerative diseases, multiple sclerosis and migraine. This is due to their well-known antioxidant, anti-inflammatory, neuroprotective, anti-tumor, anti-ischemic and analgesic properties. Nevertheless, many of these molecules have poor aqueous solubility, low bioavailability and extensive gastrointestinal and/or hepatic first-pass metabolism, leading to a quick elimination as well as low serum and tissue concentrations. Thus, the intranasal route emerged as a viable alternative to oral or parenteral administration, by enabling a direct transport into the brain through the olfactory and trigeminal nerves. With this approach, the blood-brain barrier is circumvented and peripheral exposure is reduced, thereby minimizing possible adverse effects.

OBJECTIVE

Herein, brain-targeting strategies for nose-to-brain delivery of natural compounds, including flavonoids, cannabinoids, essential oils and terpenes, will be reviewed and discussed. Brain and plasma pharmacokinetics of these molecules will be analyzed and related to their physicochemical characteristics and formulation properties.

CONCLUSION

Natural compounds constitute relevant alternatives for the treatment of brain diseases but often require loading into nanocarrier systems to reach the central nervous system in sufficient concentrations. Future challenges lie in a deeper characterization of their therapeutic mechanisms and in the development of effective, safe and brain-targeted delivery systems for their intranasal administration.

Flavonoids in adipose tissue inflammation and atherosclerosis: one arrow, two targets

Flavonoids are polyphenolic compounds naturally occurring in fruits and vegetables, in addition to beverages such as tea and coffee. Flavonoids are emerging as potent therapeutic agents for cardiovascular as well as metabolic diseases. Several studies corroborated an inverse relationship between flavonoid consumption and cardiovascular disease (CVD) or adipose tissue inflammation (ATI). Flavonoids exert their anti-atherogenic effects by increasing nitric oxide (NO), reducing reactive oxygen species (ROS), and decreasing pro-inflammatory cytokines. In addition, flavonoids alleviate ATI by decreasing triglyceride and cholesterol levels, as well as by attenuating inflammatory mediators. Furthermore, flavonoids inhibit synthesis of fatty acids and promote their oxidation. In this review, we discuss the effect of the main classes of flavonoids, namely flavones, flavonols, flavanols, flavanones, anthocyanins, and isoflavones, on atherosclerosis and ATI. In addition, we dissect the underlying molecular and cellular mechanisms of action for these flavonoids. We conclude by supporting the potential benefit for flavonoids in the management or treatment of CVD; yet, we call for more robust clinical studies for safety and pharmacokinetic values.

Resveratrol isoforms and conjugates: A review from biosynthesis in plants to elimination from the human body

The natural isomers of resveratrol, cis- and trans-resveratrol, are natural phenolic substances synthetized via the shikimate pathway and found in many sources, including grapes, peanuts, blackberries, pistachios, cacao, cranberries, and jackfruits. They have functional and pharmacological properties such as anticarcinogenic, antidiabetic, anti-inflammatory, and cardioprotective activities. The aim of this article is to review the data published on resveratrol and its isomers, and their biosynthesis in plants, food sources, health and toxic effects, and the excretion of their metabolites. Due to its contribution to the promotion of human health, it is convenient to gather more knowledge about its functional properties, food sources, and the interactions with the human body during the processes of eating, digestion, absorption, biotransformation, and excretion, to combine this information to improve the understanding of these substances.

The uses of resveratrol for neurological diseases treatment and insights for nanotechnology based-drug delivery systems

Neurological disorders have been growing in recent years and are highly prevalent globally. Resveratrol (RES) is a natural product from plant sources such as grape skins. This compound has shown biological activity in many diseases, in particular, those that act on the central nervous system. The mechanism of action and the key points in neurological disorders were described and show the targeted mechanism of action. Due to the insolubility of this compound; the use of nanotechnology-based systems has been proposed for the incorporation of RES and RES-loaded nanocarriers have been designed for intranasal administration, oral or parenteral routes to deliver it to the brain. In general, these nanosystems have shown to be effective in many studies, pharmacological and pharmacokinetic assays, as well as some cell studies. The outcomes show that RES has been reported in human clinical trials for some neurological diseases, although no studies were performed in humans using nanocarriers, animal and/or cellular models have been reported to show good results regarding therapeutics on neurological diseases. Thus, the use of this nutraceutical has shown true for neurological diseases and its loading into nanocarriers displaying good results on the stability, delivery and targeting to the brain.

Has resveratrol a potential for mucopolysaccharidosis treatment?

Mucopolysaccharidoses (MPS) represent a devastating group of lysosomal storage diseases (LSD) affecting approximately 1 in 25,000 individuals, where degradation of glycosaminoglycans (GAG) by lysosomal enzymes is impaired due to mutations causing defects in one of GAG-degrading enzymes. The most commonly used therapy for MPS is enzyme replacement therapy, consisting of application of an active form of the missing enzyme. However, supply of the missing enzyme is not enough in case of MPS types whose symptoms are expressed in central nervous system (CNS), as enzyme does not cross the blood-brain barrier. Moreover, even though enzyme replacement therapy for non-neuronopathic MPS IVA type is approved, it has a limited impact on bone abnormalities, that are one of main symptoms in the disease. Therefore, research into alternative therapeutic approaches for these types of MPS is highly desirable. One such alternative strategy is accelerated degradation of GAG by induction of autophagy. Autophagy is a process of lysosomal degradation of macromolecules that become abnormal or unnecessary for cells. One of the latest discoveries is that GAGs can also be such molecules. Potential drug should also cross blood-brain barrier and be safe in long-term therapy. It seems that one of the polyphenols, resveratrol, can meet the requirements. The mechanism of its action in autophagy stimulation is pleiotropic. Therefore, in this review, we will briefly discuss potential of resveratrol treatment for mucopolysaccharidosis through autophagy stimulation based on research in diseases with similar outcome.

Ubiquitin biology in neurodegenerative disorders: From impairment to therapeutic strategies

The abnormal accumulation of neurotoxic proteins is the typical hallmark of various age-related neurodegenerative disorders (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis and Multiple sclerosis. The anomalous proteins, such as Aβ, Tau in Alzheimer's disease and α-synuclein in Parkinson's disease, perturb the neuronal physiology and cellular homeostasis in the brain thereby affecting the millions of human lives across the globe. Here, ubiquitin proteasome system (UPS) plays a decisive role in clearing the toxic metabolites in cells, where any aberrancy is widely reported to exaggerate the neurodegenerative pathologies. In spite of well-advancement in the ubiquitination research, their molecular markers and mechanisms for target-specific protein ubiquitination and clearance remained elusive. Therefore, this review substantiates the role of UPS in the brain signaling and neuronal physiology with their mechanistic role in the NDD's specific pathogenic protein clearance. Moreover, current and future promising therapies are discussed to target UPS-mediated neurodegeneration for better public health.

Single administration of resveratrol improves social behavior in adult mouse models of autism spectrum disorder

Resveratrol (RSV) is a natural polyphenol present in grapes, the skin of peanuts, and several other plants with many health benefits. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that may be linked to neural and synaptic development impairments. The present study aimed to analyze the preventive effects of RSV on the development of ASD-like behavior, using oxytocin receptor gene knockout (Oxtr-KO) and valproic acid-induced ASD (VPA-ASD) model mice. Genetic deficiencies in Oxtr are suggested to be involved in ASD etiology. Twenty-four hours after a single RSV injection to the Oxtr-KO mice, the social impairments caused by OXTR deficiency were ameliorated. RSV also improved social impairments in the VPA-ASD mice. Administration of RSV up-regulated silent information regulator 1 (Sirt1) gene and early growth response factor 3 (Egr3) gene expressions in the amygdala of the Oxtr-KO mice. Our data suggest that RSV may have therapeutic effects on ASD with multiple targets.

Oral Delivery of β-Lactoglobulin-Nanosphere-Encapsulated Resveratrol Alleviates Inflammation in Winnie Mice with Spontaneous Ulcerative Colitis

Resveratrol (RES) is a nutraceutical with promising anti-inflammatory properties for the treatment of inflammatory bowel diseases (IBD). However, the clinical effectiveness of resveratrol as an oral anti-inflammatory agent is hindered by its extremely poor solubility and poor stability. In this study, we encapsulated resveratrol in β-lactoglobulin (BLG) nanospheres and systematically analyzed their formulation parameters in vitro followed by a thorough in vivo anti-inflammatory testing in a highly specialized spontaneous murine UC model (Winnie mice model). Complexation of resveratrol with BLG increased the aqueous solubility of resveratrol by ≈1.7 times with 10% w/w loading. Additionally, the in vitro dissolution of resveratrol from the particles was found to be higher compared to resveratrol alone, resulting in >90% resveratrol dissolution in ∼8 h. The anti-inflammatory activity of resveratrol was examined for the first time in Winnie mice, a mouse model that closely represents the clinical signs of IBD. At a 50 mg/kg oral dose for 2 weeks, BLG-RES significantly improved both % body weight and disease activity index (DAI), compared to free resveratrol in Winnie mice. Importantly, histological evaluations revealed a similar trend with striking improvement in the pathology of the colon via an increase in goblet cell numbers and recovery of colonic epithelium. BLG-RES significantly increased the expression level of cytokine interleukin-10 (Il10), which confirms the reduction in inflammation potentially because of the increased dissolution and stability of resveratrol by complexation with BLG. This comprehensive study demonstrates the effectiveness of biocompatible nanomaterials such as BLG in oral delivery of poorly soluble anti-inflammatory molecules such as resveratrol in the treatment of IBD.

Impact of Natural Compounds on Neurodegenerative Disorders: From Preclinical to Pharmacotherapeutics

Among the major neurodegenerative disorders (NDDs), Alzheimer’s disease (AD) and Parkinson’s disease (PD), are a huge socioeconomic burden. Over many centuries, people have sought a cure for NDDs from the natural herbals. Many medicinal plants and their secondary metabolites are reported with the ability to alleviate the symptoms of NDDs. The major mechanisms identified, through which phytochemicals exert their neuroprotective effects and potential maintenance of neurological health in ageing, include antioxidant, anti-inflammatory, antithrombotic, antiapoptotic, acetylcholinesterase and monoamine oxidase inhibition and neurotrophic activities. This article reviews the mechanisms of action of some of the major herbal products with potential in the treatment of NDDs according to their molecular targets, as well as their regional sources (Asia, America and Africa). A number of studies demonstrated the beneficial properties of plant extracts or their bioactive compounds against NDDs. Herbal products may potentially offer new treatment options for patients with NDDs, which is a cheaper and culturally suitable alternative to conventional therapies for millions of people in the world with age-related NDDs.

Potential Adverse Effects of Resveratrol: A Literature Review

Due to its health benefits, resveratrol (RE) is one of the most researched natural polyphenols. Resveratrol's health benefits were first highlighted in the early 1990s in the French paradox study, which opened extensive research activity into this compound. Ever since, several pharmacological activities including antioxidant, anti-aging, anti-inflammatory, anti-cancerous, anti-diabetic, cardioprotective, and neuroprotective properties, were attributed to RE. However, results from the available human clinical trials were controversial concerning the protective effects of RE against diseases and their sequelae. The reason for these conflicting findings is varied but differences in the characteristics of the enrolled patients, RE doses used, and duration of RE supplementation were proposed, at least in part, as possible causes. In particular, the optimal RE dosage capable of maximizing its health benefits without raising toxicity issues remains an area of extensive research. In this context, while there is a consistent body of literature on the protective effects of RE against diseases, there are relatively few reports investigating its possible toxicity. Indeed, toxicity and adverse effects were reported following consumption of RE; therefore, extensive future studies on the long-term effects, as well as the in vivo adverse effects, of RE supplementation in humans are needed. Furthermore, data on the interactions of RE when combined with other therapies are still lacking, as well as results related to its absorption and bioavailability in the human body. In this review, we collect and summarize the available literature about RE toxicity and side effects. In this process, we analyze in vitro and in vivo studies that have addressed this stilbenoid. These studies suggest that RE still has an unexplored side. Finally, we discuss the new delivery methods that are being employed to overcome the low bioavailability of RE.

Research Progress on Alzheimer's Disease and Resveratrol

Alzheimer's disease (AD), a common irreversible neurodegenerative disease characterized by amyloid-β plaques, neurofibrillary tangles, and changes in tau phosphorylation, is accompanied by memory loss and symptoms of cognitive dysfunction. Increases in disease incidence due to the ageing of the population have placed a great burden on society. To date, the mechanism of AD and the identities of adequate drugs for AD prevention and treatment have eluded the medical community. It has been confirmed that phytochemicals have certain neuroprotective effects against AD. For example, some progress has been made in research on the use of resveratrol, a natural polyphenolic phytochemical, for the prevention and treatment of AD in recent years. Elucidation of the pathogenesis of AD will create a solid foundation for drug treatment. In addition, research on resveratrol, including its mechanism of action, the roles of signalling pathways and its therapeutic targets, will provide new ideas for AD treatment, which is of great significance. In this review, we discuss the possible relationships between AD and the following factors: synapses, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs), silent information regulator 1 (SIRT1), and estrogens. We also discuss the findings of previous studies regarding these relationships in the context of AD treatment and further summarize research progress related to resveratrol treatment.

Review on the Structures and Activities of Transthyretin Amyloidogenesis Inhibitors

Transthyretin (TTR) is a tetrameric protein, and its dissociation, aggregation, deposition, and misfolding are linked to several human amyloid diseases. As the main transporter for thyroxine (T4) in plasma and cerebrospinal fluid, TTR contains two T4-binding sites, which are docked with T4 and subsequently maintain the structural stability of TTR homotetramer. Affected by genetic disorders and detrimental environmental factors, TTR degrades to monomer and/or form amyloid fibrils. Reasonably, stabilization of TTR might be an efficient strategy for the treatment of TTR-related amyloidosis. However, only 10-25% of T4 in the plasma is bound to TTR under physiological conditions. Expectedly, T4 analogs with different structures aiming to bind to T4 pockets may displace the functions of T4. So far, a number of compounds including both natural and synthetic origin have been reported. In this paper, we summarized the potent inhibitors, including bisaryl structure-based compounds, flavonoids, crown ethers, and carboranes, for treating TTR-related amyloid diseases and the combination modes of some compounds binding to TTR protein.

An Overview of Crucial Dietary Substances and Their Modes of Action for Prevention of Neurodegenerative Diseases

Neurodegenerative diseases, namely Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis are becoming one of the main health concerns due to the increasing aging of the world's population. These diseases often share the same biological mechanisms, including neuroinflammation, oxidative stress, and/or protein fibrillation. Recently, there have been many studies published pointing out the possibilities to reduce and postpone the clinical manifestation of these deadly diseases through lifelong consumption of some crucial dietary substances, among which phytochemicals (e.g., polyphenols) and endogenous substances (e.g., acetyl-L-carnitine, coenzyme Q10, n-3 poysaturated fatty acids) showed the most promising results. Another important issue that has been pointed out recently is the availability of these substances to the central nervous system, where they have to be present in high enough concentrations in order to exhibit their neuroprotective properties. As so, such the aim of this review is to summarize the recent findings regarding neuroprotective substances, their mechanisms of action, as well as to point out therapeutic considerations, including their bioavailability and safety for humans.

Resveratrol in Autism Spectrum Disorders: Behavioral and Molecular Effects

Resveratrol (RSV) is a polyphenolic stillbenoid with significant anti-oxidative and anti-inflammatory properties recently tested in animal models of several neurological diseases. Altered immune alteration and oxidative stress have also been found in patients with autism spectrum disorders (ASD), and these alterations could add to the pathophysiology associated with ASD. We reviewed the current evidence about the effects of RSV administration in animal models and in patients with ASD. RSV administration improves the core-symptoms (social impairment and stereotyped activity) in animal models and it also displays beneficial effects in other behavioral abnormalities such as hyperactivity, anxiety and cognitive function. The molecular mechanisms by which RSV restores or improves behavioral abnormalities in animal models encompass both normalization of central and peripheral immune alteration and oxidative stress markers and new molecular mechanisms such as expression of cortical gamma-amino butyric acid neurons, certain type of miRNAs that regulate spine growth. One randomized, placebo-controlled clinical trial (RCT) suggested that RSV add-on risperidone therapy improves comorbid hyperactivity/non-compliance, whereas no effects where seen in core symptoms of ASD No RCTs about the effect of RSV as monotherapy have been performed and the results from preclinical studies encourage its feasibility. Further clinical trials should also identify those ASD patients with immune alterations and/or with increased oxidative stress markers that would likely benefit from RSV administration.

The Plant-Derived Compound Resveratrol in Brain Cancer: A Review

Despite intensive research, malignant brain tumors are among the most difficult to treat due to high resistance to conventional therapeutic approaches. High-grade malignant gliomas, including glioblastoma and anaplastic astrocytoma, are among the most devastating and rapidly growing cancers. Despite the ability of standard treatment agents to achieve therapeutic concentrations in the brain, malignant gliomas are often resistant to alkylating agents. Resveratrol is a plant polyphenol occurring in nuts, berries, grapes, and red wine. Resveratrol crosses the blood‒brain barrier and may influence the central nervous system. Moreover, it influences the enzyme isocitrate dehydrogenase and, more importantly, the resistance to standard treatment via various mechanisms, such as O6-methylguanine methyltransferase. This review summarizes the anticancer effects of resveratrol in various types of brain cancer. Several in vitro and in vivo studies have presented promising results; however, further clinical research is necessary to prove the therapeutic efficacy of resveratrol in brain cancer treatment.

Co-Delivery of Curcumin and Paclitaxel by "Core-Shell" Targeting Amphiphilic Copolymer to Reverse Resistance in the Treatment of Ovarian Cancer

Background

Ovarian cancer is a common malignancy in the female reproductive system with a high mortality rate. The most important reason is multidrug resistance (MDR) of cancer chemotherapy. To reduce side effects, reverse resistance and improve efficacy for the treatment of ovarian cancer, a “core-shell” polymeric nanoparticle-mediated curcumin and paclitaxel co-delivery platform was designed.

Methods

Nuclear magnetic resonance confirmed the successful grafting of polyethylenimine (PEI) and stearic acid (SA) (PEI-SA), which is designed as a mother core for transport carrier. Then, PEI-SA was modified with hyaluronic acid (HA) and physicochemical properties were examined. To understand the regulatory mechanism of resistance and measure the anti-tumor efficacy of the treatments, cytotoxicity assay, cellular uptake, P-glycoprotein (P-gp) expression and migration experiment of ovarian cancer cells were performed. In addition, adverse reactions of nanoformulation to the reproductive system were examined.

Results

HA-modified drug-loaded PEI-SA had a narrow size of about 189 nm in diameters, and the particle size was suitable for endocytosis. The nanocarrier could target specifically to CD44 receptor on the ovarian cancer cell membrane. Co-delivery of curcumin and paclitaxel by the nanocarriers exerts synergistic anti-ovarian cancer effects on chemosensitive human ovarian cancer cells (SKOV3) and multi-drug resistant variant (SKOV3-TR30) in vitro, and it also shows a good anti-tumor effect in ovarian tumor-bearing nude mice. The mechanism of reversing drug resistance may be that the nanoparticles inhibit the efflux of P-gp, inhibit the migration of tumor cells, and curcumin synergistically reverses the resistance of PTX to increase antitumor activity. It is worth noting that the treatment did not cause significant toxicity to the uterus and ovaries with the observation of macroscopic and microscopic.

Conclusion

This special structure of targeting nanoparticles co-delivery with the curcumin and paclitaxel can increase the anti-tumor efficacy without increasing the adverse reactions as a promising strategy for therapy ovarian cancer.

Pharmacokinetics and brain targeting of trans-resveratrol loaded mixed micelles in rats following intravenous administration

Trans-Resveratrol (T-RES) is a compound with wide therapeutic applications that shows low bioavailability and distribution across blood-brain barrier. The purpose of our study was to develop T-RES loaded mixed micelle (T-RES-MM) for its enhanced systemic availability and targeting to the brain. T-RES-MMs were formulated using Pluronic F-127 (PF-127) and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) by using film hydration process. Formulations were characterized for size of particles, zeta potential, drug efficiency of entrapment, drug loading, and hemolytic study. Further in vivo pharmacokinetic and brain distribution study carried out in Sprague Dawley rats. The nano ranged size for drug-loaded mixed micelles was 21.55 ± 2.15 nm for optimized formulation with PF-127:TPGS (4:1). Formulation with maximum drug loading and entrapment efficiency of 8.4 ± 0.37% and 94.37 ± 1.01% respectively were further used for in vivo study. Percent hemolysis by micelles at all concentrations indicates the biocompatibility and safety for administration by i.v. route. The AUC_0-t for T-RES-MM was 460.98 ± 158.99 h*ng/ml while for T-RES it was 276.27 ± 174.05 h*ng/ml. Drug targeting index suggests successful targeting of T-RES to the brain. Overall findings conclude in prepared T-RES-MM exhibit superiority of formulation as compared to T-RES solution.

α-Helical cell-penetrating peptide-mediated nasal delivery of resveratrol for inhibition of epithelial-to-mesenchymal transition

In the present study, we examined the potential of cell-penetrating peptide (CPP)-based intranasal drug delivery for the treatment of localized nasal diseases. Many charged or non-hydrophobic drugs have difficulty penetrating into the nasal epithelium due to intrinsic membrane impermeability and rapid mucociliary clearance in the nasal cavity. To treat chronic rhinosinusitis with nasal polyps (CRSwNP), one of the most common localized nasal diseases, we conjugated resveratrol (RSV) to an amphiphilic α-helical leucine (L)- and lysine (K)-rich CPP (LK) and intranasally delivered it to the interior of nasal epithelial cells for inhibiting epithelial-to-mesenchymal transition (EMT) caused by hypoxia-inducible factor 1α. The RSV-LK conjugate could penetrate into the nasal epithelium and efficiently inhibit EMT, nasal polyp formation, epithelial disruption, and related inflammation in an eosinophilic CRSwNP mouse model, at 10-fold lower doses and with 3-fold less frequent administration than free RSV. Due to the rapid penetration into the nasal epithelium and the therapeutic effect of the RSV-LK conjugate at much lower doses than free RSV, this CPP-based delivery system, with the ability to overcome the tight nasal epithelial barrier, may provide a new strategy for the treatment of localized nasal diseases without the systemic side effects of cargo drugs.

Chitosan Oleate Coated Poly Lactic-Glycolic Acid (PLGA) Nanoparticles versus Chitosan Oleate Self-Assembled Polymeric Micelles, Loaded with Resveratrol

Chitosan oleate (CS-OA), a chitosan salt with amphiphilic properties, has demonstrated the ability to self-assemble in aqueous environment to give polymeric micelles useful to load poorly soluble drugs. More recently, CS-OA was proposed to stabilize nanoemulsions during the preparation by emulsification and solvent evaporation of poly lactic-glycolic acid (PLGA) nanoparticles (NPs) loaded with curcumin. Positive mucoadhesive behavior and internalization properties were demonstrated for these NPs attributable to the presence of positive charge at the NP surface. In the present paper, two CS-OA-based nanosystems, micelles and PLGA NPs, were compared with the aim of elucidating their physico-chemical characteristics, and especially their interaction with cell substrates. The two systems were loaded with resveratrol (RSV), a hydrophobic polyphenol endowed with anti-cancerogenic, anti-inflammatory, and heart/brain protective effects, but with low bioavailability mainly due to poor aqueous solubility. Calorimetric analysis and X-ray spectra demonstrated amorphization of RSV, confirming its affinity for hydrophobic domains of polymeric micelles and PLGA core of NPs. TGA decomposition patterns suggest higher stability of PLGA-NPs compared with polymeric micelles, that anyway resulted more stable than expected, considering the RSV release profiles, and the cell line interaction results.

Multicomponent self nano emulsifying delivery systems of resveratrol with enhanced pharmacokinetics profile

Resveratrol is a drug with high potential for clinical application based on experimental models. Though, resveratrol translation to clinical use has not been successful yet due to its poor pharmacokinetics, related to poor solubility and fast metabolism. The use of drug delivery systems, namely self-emulsifying drug delivery systems (SEDDS), may be a viable strategy to overcome the poor in vivo performance of resveratrol. In this work, a rational development of two different ternary SEDDS was conducted. Experimental data showed that quantitative variations on SEDDS composition impacted dispersion and robustness to dilution of SEDDS, as well as loading capacity and droplet size. Formulations composed of Lauroglycol® 90/Labrasol®/Capryol® PGMC (12.5/75.0/12.5) (Lau/Lab/Cap) and Tween® 80/Transcutol®/Imwitor® 742 (33.3/33.3/33.3) (T80/Trans/Imw) featured improved performance and were selected for further studies. T80/Trans/Imw formulation yield faster emulsification and originated smaller droplet size, with lower cumulative percentile of 90% of particles (D₉₀) (below 200 nm), as compared to the than Lau/Lab/Cap formulation. Higher resveratrol permeation rate was observed in Caco-2 cell monolayer permeability studies for both formulations as compared to the free drug. Reduction of the metabolization and/or efflux of resveratrol was also noticed in the case of SEDDs, as suggested by the increased recovery of total drug. Plasmatic drug concentrations in rats observed after oral gavage indicate that both formulations provided faster resveratrol absorption than free drug, resulting in shorter T_max values (30 min vs. 2 h). No statistically significant differences were observed for AUC_0-t values of both formulations and the free drug. Still, C_max for the Lau/Lab/Cap SEDDs formulation was 2-fold higher than for the free drug. These findings suggest that SEDDS can increase resveratrol solubility and reduce its metabolization, resulting in an overall improvement of its oral pharmacokinetics profile.

Phytochemicals Bridging Autophagy Induction and Alpha-Synuclein Degradation in Parkinsonism

Among nutraceuticals, phytochemical-rich compounds represent a source of naturally-derived bioactive principles, which are extensively studied for potential beneficial effects in a variety of disorders ranging from cardiovascular and metabolic diseases to cancer and neurodegeneration. In the brain, phytochemicals produce a number of biological effects such as modulation of neurotransmitter activity, growth factor induction, antioxidant and anti-inflammatory activity, stem cell modulation/neurogenesis, regulation of mitochondrial homeostasis, and counteracting protein aggregation through modulation of protein-folding chaperones and the cell clearing systems autophagy and proteasome. In particular, the ability of phytochemicals in restoring proteostasis through autophagy induction took center stage in recent research on neurodegenerative disorders such as Parkinson’s disease (PD). Indeed, autophagy dysfunctions and α-syn aggregation represent two interdependent downstream biochemical events, which concur in the parkinsonian brain, and which are targeted by phytochemicals administration. Therefore, in the present review we discuss evidence about the autophagy-based neuroprotective effects of specific phytochemical-rich plants in experimental parkinsonism, with a special focus on their ability to counteract alpha-synuclein aggregation and toxicity. Although further studies are needed to confirm the autophagy-based effects of some phytochemicals in parkinsonism, the evidence discussed here suggests that rescuing autophagy through natural compounds may play a role in preserving dopamine (DA) neuron integrity by counteracting the aggregation, toxicity, and prion-like spreading of α-syn, which remains a hallmark of PD.

Expression pattern of thaumatin in the selected red varieties of Vitis vinifera, L

Vitis vinifera L. is a specie that is adapted to a very variable range of climates, from cold up to the desert one, but especially it grows in the temperate Mediterranean regions and continental areas of Europe. Grape is a widespread consumed fruit as well as processed to musts, juices or wine. The health beneficial effects of grapes and wine are very well known due to their high nutritional value and unique phytochemical composition. Despite many health protective and beneficial effects of Vitis vinifera, a part of population suffer to allergic reactions to this fruit. Allergens of wine and grapes are: endochitinases, lipid-transfer protein and thaumatin. Thaumatin is a protein having a sweet taste belonging to the PR5-like proteins.  These proteins are very difersified in their functions and were described to be involved in stress responses and fruit ripening, but are expressed in healthy grape fruits in a constitutive manner and needn´t to be expressed only as a answer to the stress. Thaumatin is a minor allergen in grape, but belonging to the suspected panallergens relevant to the food cross-allergy induction, its importance is quite high. Another importance of this protein is a technological one, as reported to aggregate in wine to form a visible haze unless removed prior to bottling. In this study, expression of thaumatin-like allergen was analysed in the grapes of selected varieties. Grapes of four red varieties of Vitis vinifera, L. were obtained in the season 2017 in the Sabo winery  that belongs to the Malokarpatská wine region. Fresh maturated grapes of varieties Alibernet, Cabernet Sauvignon , Frankovka modrá and Dornfelder were analysed. Expression changes of thaumatin was calculated by delta delta Ct method.  Dornfelder was found as to have the lowest activity in thaumatin-like gene activity,  mainly when comparing to the Cabernet Sauvignon and Frankovka modrá. Alibernet, on the other side, has the expression level of thaumatin very similar when comparing to the Cabernet Sauvignon and Frankovka modrá.

Baicalein Exerts Neuroprotective Effects in FeCl3-Induced Posttraumatic Epileptic Seizures via Suppressing Ferroptosis

Posttraumatic epilepsy (PTE) is a prevalent type of acquired epilepsy secondary to traumatic brain injury, and is characterized by repeated seizures. Traditional antiepileptic drugs have minimal response in preventing posttraumatic epileptic seizures. It is essential for the development of new therapeutic strategy. Our previous work disclosed a potent neuroprotective role of baicalein, a flavonoid extracted from Scutellaria baicalensis Georgi, against inherited epilepsy in rats. Whether baicalein has protective potential in posttraumatic epileptic seizures and the possible molecular mechanism remain elusive. Additionally, the brain is vulnerable to lipid peroxidation-induced damage due to high consumption of oxygen and abundant polyunsaturated fatty acids in neuronal membranes. Our present investigation aimed to elucidate whether baicalein exerts neuroprotective effects on posttraumatic epileptic seizures by inhibiting ferroptosis, a newly discovered lipid peroxidation-dependent cell death modality. We found that baicalein significantly reduced seizure score, number of seizures, and average seizure duration in an iron chloride (FeCl₃)-induced PTE mouse model. The neuroprotective effect of baicalein was also validated in a ferric ammonium citrate (FAC)-induced HT22 hippocampal neuron damage model. Moreover, in vitro, baicalein could remarkably decrease ferroptotic indices (lipid reactive oxygen species, 4-hydroxynonenal, and prostaglandin endoperoxide synthase 2) and inhibit the expression of 12/15-lipoxygenase (12/15-LOX) in an iron-induced HT22 cell damage model. These findings were also validated in a mouse PTE model. It was concluded that baicalein exerted neuroprotective effects against posttraumatic epileptic seizures via suppressing ferroptosis and 12/15-LOX was likely to be involved in baicalein’s neuroprotection.

Natural Compounds for Alzheimer's Disease Therapy: A Systematic Review of Preclinical and Clinical Studies

Alzheimer's Disease (AD) is a neurodegenerative disorder related with the increase of age and it is the main cause of dementia in the world. AD affects cognitive functions, such as memory, with an intensity that leads to several functional losses. The continuous increase of AD incidence demands for an urgent development of effective therapeutic strategies. Despite the extensive research on this disease, only a few drugs able to delay the progression of the disease are currently available. In the last years, several compounds with pharmacological activities isolated from plants, animals and microorganisms, revealed to have beneficial effects for the treatment of AD, targeting different pathological mechanisms. Thus, a wide range of natural compounds may play a relevant role in the prevention of AD and have proven to be efficient in different preclinical and clinical studies. This work aims to review the natural compounds that until this date were described as having significant benefits for this neurological disease, focusing on studies that present clinical trials.

Biophysical interaction of temozolomide and its active metabolite with biomembrane models: The relevance of drug-membrane interaction for Glioblastoma Multiforme therapy

Temozolomide (TMZ) is the first-line treatment for Glioblastoma Multiforme (GBM). After administration, TMZ is rapidly converted into its active metabolite (MTIC). However, its pharmacological activity is reduced due MTIC low bioavailability in the brain. Since drugs' permeability through biological barriers and tumor cell membranes affects its bioavailability, the ability of MTIC to interact with the biological membranes presents a major contribution on its pharmacological properties and activity. Biomembrane models mimic the physiological conditions, allowing to predict the drug's behavior at biological membranes and its effects on drug biodistribution profiles. In this work, lipid bilayer models using liposomes were applied for the drug-membrane interaction studies. The zwitterionic phospholipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and cholesterol were chosen for the composition of the model, since they represent the major components of the membranes of GBM cells and brain capillary endothelial cell. Thus, the molecular interactions between MTIC and these models were studied by the evaluation of the partition of the drug into the phospholipid's membrane, its location within the bilayer and its effect on the fluidity of the membrane. The attained results suggest that the composition of membranes affects drugs partition, showing that drug biodistribution depends not only on its physicochemical features, but also depends on the characteristics of the membrane such as the packing of the lipid molecules. Also, MTIC exhibited low affinity to biological membranes, explaining its low bioavailability on the target cells.