Phytochemicals as Regulators of Genes Involved in Synucleinopathies

Neolignans in Magnolia officinalis as natural anti-Alzheimer's disease agents: A systematic review

BACKGROUND

Magnolia officinalis, a traditional herbal medicine widely used in clinical practice, exerts antibacterial, anti-tumor, anti-inflammatory, antioxidant, and anti-aging activities. Neolignans are the main active ingredients of M. officinalis and exert a wide range of pharmacological effects, including anti-Alzheimer's disease (AD) activity.

OBJECTIVE

To summarize the published data on the therapeutic effect and mechanism of neolignans on AD in vivo and in vitro.

METHODS

PubMed, Web of Science, Google Scholar, and Scopus were systematically reviewed (up to March 1, 2024) for pre-clinical studies.

RESULTS

M. officinalis-derived neolignans (honokiol, magnolol, 4-O-methylhonokiol, and obovatol) alleviated behavioral abnormalities, including learning and cognitive impairments, in AD animal models. Mechanistically, neolignans inhibited Aβ generation or aggregation, neuroinflammation, and acetylcholinesterase activity; promoted microglial phagocytosis and anti-oxidative stress; alleviated mitochondrial dysfunction and energy metabolism, as well as anti-cholinergic deficiency; and regulated intestinal flora. Furthermore, neolignans may achieve neuroprotection by regulating different molecular pathways, including the NF-κB, ERK, AMPK/mTOR/ULK1, and cAMP/PKA/CREB pathways.

CONCLUSIONS

Neolignans exert anti-AD effects through multiple mechanisms and pathways. However, the exact targets, pharmacokinetics, safety, and clinical efficacy in patients with AD need further investigation in multi-center clinical case-control studies.

A lupin protein hydrolysate protects the central nervous system from oxidative stress in WD-fed ApoE-/- mice

Oxidative stress plays a crucial role in neurodegenerative diseases like Parkinson's and Alzheimer's. Studies indicate the relationship between oxidative stress and the brain damage caused by a high-fat diet. It is previously found that a lupin protein hydrolysate (LPH) has antioxidant effects on human leukocytes, as well as on the plasma and liver of Western diet (WD)-fed ApoE-/- mice. Additionally, LPH shows anxiolytic effects in these mice. Given the connection between oxidative stress and anxiety, this study aimed to investigate the antioxidant effects of LPH on the brain of WD-fed ApoE-/- mice. LPH (100 mg kg-1) or a vehicle is administered daily for 12 weeks. Peptide analysis of LPH identified 101 amino acid sequences (36.33%) with antioxidant motifs. Treatment with LPH palliated the decrease in total antioxidant activity caused by WD ingestion and regulated the nitric oxide synthesis pathway in the brain of the animals. Furthermore, LPH increased cerebral glutathione levels and the activity of catalase and glutathione reductase antioxidant enzymes and reduced the 8-hydroxy-2'-deoxyguanosine levels, a DNA damage marker. These findings, for the first time, highlight the antioxidant activity of LPH in the brain. This hydrolysate could potentially be used in future nutraceutical therapies for neurodegenerative diseases.

Integrating Phenotypic and Chemoproteomic Approaches to Identify Covalent Targets of Dietary Electrophiles in Platelets

A large variety of dietary phytochemicals has been shown to improve thrombosis and stroke outcomes in preclinical studies. Many of these compounds feature electrophilic functionalities that potentially undergo covalent addition to the sulfhydryl side chain of cysteine residues within proteins. However, the impact of such covalent modifications on the platelet activity and function remains unclear. This study explores the irreversible engagement of 23 electrophilic phytochemicals with platelets, unveiling the unique antiplatelet selectivity of sulforaphane (SFN). SFN impairs platelet responses to adenosine diphosphate (ADP) and a thromboxane A2 receptor agonist while not affecting thrombin and collagen-related peptide activation. It also substantially reduces platelet thrombus formation under arterial flow conditions. Using an alkyne-integrated probe, protein disulfide isomerase A6 (PDIA6) was identified as a rapid kinetic responder to SFN. Mechanistic profiling studies revealed SFN's nuanced modulation of PDIA6 activity and substrate specificity. In an electrolytic injury model of thrombosis, SFN enhanced the thrombolytic activity of recombinant tissue plasminogen activator (rtPA) without increasing blood loss. Our results serve as a catalyst for further investigations into the preventive and therapeutic mechanisms of dietary antiplatelets, aiming to enhance the clot-busting power of rtPA, currently the only approved therapeutic for stroke recanalization that has significant limitations.

Therapeutic Potential of Natural Compounds from Herbs and Nutraceuticals in Alleviating Neurological Disorders: Targeting the Wnt Signaling Pathway

As an important signaling pathway in multicellular eukaryotes, the Wnt signaling pathway participates in a variety of physiological processes. Recent studies have confirmed that the Wnt signaling pathway plays an important role in neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. The regulation of Wnt signaling by natural compounds in herbal medicines and nutraceuticals has emerged as a potential strategy for the development of new drugs for neurological disorders. Purpose: The aim of this review is to evaluate the latest research results on the efficacy of natural compounds derived from herbs and nutraceuticals in the prevention and treatment of neurological disorders by regulating the Wnt pathway in vivo and in vitro. A manual and electronic search was performed for English articles available from PubMed, Web of Science, and ScienceDirect from the January 2010 to February 2023. Keywords used for the search engines were "natural products,″ "plant derived products,″ "Wnt+ clinical trials,″ and "Wnt+,″ and/or paired with "natural products″/″plant derived products", and "neurological disorders." A total of 22 articles were enrolled in this review, and a variety of natural compounds from herbal medicine and nutritional foods have been shown to exert therapeutic effects on neurological disorders through the Wnt pathway, including curcumin, resveratrol, and querctrin, etc. These natural products possess antioxidant, anti-inflammatory, and angiogenic properties, confer neurovascular unit and blood-brain barrier integrity protection, and affect neural stem cell differentiation, synaptic formation, and neurogenesis, to play a therapeutic role in neurological disorders. In various in vivo and in vitro studies and clinical trials, these natural compounds have been shown to be safe and tolerable with few adverse effects. Natural compounds may serve a therapeutic role in neurological disorders by regulating the Wnt pathway. This summary of the research progress of natural compounds targeting the Wnt pathway may provide new insights for the treatment of neurological disorders and potential targets for the development of new drugs.

In-vitro and In Silico Assessment of Anti-inflammation Properties of Saponarin Extracted from Hordeum Vulgare

BACKGROUND

Hordeum vulgare, commonly known as Barley grass, is a historically significant cultivated plant with profound implications for societies, agricultural sciences, and human nutrition. It has been valued for both sustenance and its potential medicinal properties.

OBJECTIVES

This study aims to comprehensively investigate the medicinal properties of Hordeum vulgare, focusing on its potential therapeutic benefits and anti-inflammatory properties. Additionally, we seek to quantify and compare the phytochemical content of two distinct extracts: Barley Grass Hexane Extract (BGHE) and Barley grass aqueous extract (BGAQ).

METHODS

We quantified the phytochemical contents of BGHE and BGAQ and evaluated their anti-inflammatory effects using UV spectroscopy at 560 nm, coupled with the RBC membrane stabilization technique. Subsequently, we conducted in silico studies to assess the in vitro anti-inflammatory potential of Barley grass leaf extracts.

RESULTS

Both BGHE and BGAQ demonstrated significant inhibitory effects on inflammation compared to the control group. However, BGHE exhibited superior anti-inflammatory efficacy when compared to BGAQ, suggesting its role as a potential anti-inflammatory agent. In silico studies further supported the anti-inflammatory potential of Barley grass leaf extracts.

CONCLUSION

Hordeum vulgare, or Barley grass, offers a wealth of health benefits, including anti-inflammatory, anti-diabetic, anti-cancer, antioxidant, anti-acne, and anti-depressant properties. These properties contribute to improved immunity, reduced cardiovascular disorders, and alleviation of fatigue. The distinct extracts, BGHE and BGAQ, both exhibit promising anti-inflammatory capabilities, but BGHE shows better anti-inflammatory activity. This research sheds light on the therapeutic potential of Barley grass, making it a valuable candidate for further exploration in the field of natural medicine.

Flavonoids: Their putative neurologic roles, epigenetic changes, and gut microbiota alterations in Parkinson's disease

Parkinson's Disease (PD), a neurodegenerative disorder, is characterized by the degeneration of progressive dopaminergic (DA) neurons in the substantia nigra region of the human midbrain. Although just what causes PD remains a mystery, it is known that oxidative stress (OS) as well as mitochondrial dysfunction, neuro-inflammation, and insufficient neurotrophic support play a role in the disease's pathophysiology. Phytochemicals are a diverse small molecule group derived from plants that can be classified into numerous classes on the basis of their biological activities and chemical structure. Of these groups of phytochemicals, the most abundant, which has well-established anti-Parkinson's effects, are polyphenols. Flavonoids, including naringin and naringenin, genistein, kaempferol, anthocyanins, epigallocatechin-3-gallate, and baicalein are plant-based biologically active polyphenols, which have been shown to exhibit therapeutic potential when used as treatment for a variety of pathological illnesses, such as neurodegenerative diseases (NDs) and PD. Recently, it was reported that flavonoids have beneficial effects on PD, such as the protection of DA neurons, improvement of motor and cognitive abilities, regulation of signaling pathways, and modulation of OS and neuro-inflammation. In addition, by changing the composition of bacteria in gut microbiota, flavonoids reduce pathogenic strains and promote the growth of beneficial strains. In this context, the current paper will provide a literature review on the neurological roles that flavonoids play, as one of the most abundant phytochemical families, in PD.

Constituent isoflavones of Puerariae radix as a potential neuroprotector in cognitive impairment: Evidence from preclinical studies

With the increasing aging population worldwide, the incidence of senile cognitive impairment (CI) is increasing, posing a serious threat to the health of elderly persons. Despite developing new drugs aimed at improving CI, progress in this regard has been insufficient. Natural preparations derived from plants have become an unparalleled resource for developing new drugs. Puerariae radix (PR) has a long history as Chinese herbal medicine. PR is rich in various chemical components such as isoflavones, triterpenes, and saponins. The isoflavones (puerarin, daidzein, formononetin, and genistein) exhibit potential therapeutic effects on CI through multiple mechanisms. Relevant literature was organized from major scientific databases such as PubMed, Elsevier, SpringerLink, ScienceDirect, and Web of Science. Using "Puerariae radix," "Pueraria lobata," "isoflavones," "puerarin," "antioxidant," "daidzein," "formononetin," "genistein," "Alzheimer"s disease," and "vascular cognitive impairment" as keywords, the relevant literature was extracted from the databases mentioned above. We found that isoflavones from PR have neuroprotective effects on multiple models of CI via multiple targets and mechanisms. These isoflavones prevent Aβ aggregation, inhibit tau hyperphosphorylation, increase cholinergic neurotransmitter levels, reduce neuroinflammation and oxidative stress, improve synaptic plasticity, promote nerve regeneration, and prevent apoptosis. PR has been used as traditional Chinese herbal medicine for a long time, and its constituent isoflavones exert significant therapeutic effects on CI through various neuroprotective mechanisms. This review will contribute to the future development of isoflavones present in PR as novel drug candidates for the clinical treatment of CI.

Trigonella foenum-graecum L. seed extract modulates biochemical and histomorphological changes in therapeutic model of high-fat diet-fed ovariectomized rats

This study investigates the therapeutic effect of petroleum ether fraction of Trigonella foenum-graecum L. (PE-TFG) seed extract in ovariectomized rats fed with high-fat diet. Rats were randomly grouped into sham ovariectomy (S.OVX), ovariectomy + high-fat diet (OVX + HFD), and treatment groups. The blood samples were collected, and lipid profile, glucose, hepatic markers, and inflammatory markers were estimated. Liver, kidney, and common carotid artery were isolated for histopathological observations. Liver samples were tested for antioxidant, oxidative stress markers, mRNA expression of adiponectin, and PPAR-γ. PE-TFG treatment significantly decreased total cholesterol (18%), LDL (20%), hepatic markers (28%), leptin (17%), TNF-α (21%), and increased mRNA expression of adiponectin and PPAR-γ. There was also micro- and macro-hepatic steatosis, inflammation in the liver, deteriorated tubules in the kidney, and increased tunica intima and media thickness of the common carotid artery. These pathological alterations were reversed with PE-TFG administration. This impact might be linked to phytoestrogens and other components in PE-TFG such as diosgenin, phenols, and flavonoids.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03707-8.

Phytochemicals targeting lncRNAs: A novel direction for neuroprotection in neurological disorders

Neurological disorders with various etiologies impacting the nervous system are prevalent in clinical practice. Long non-coding RNA (lncRNA) molecules are functional RNA molecules exceeding 200 nucleotides in length that do not encode proteins, but participate in essential activities. Research indicates that lncRNAs may contribute to the pathogenesis of neurological disorders, and may be potential targets for their treatment. Phytochemicals in traditional Chinese herbal medicine (CHM) have been found to exert neuroprotective effects by targeting lncRNAs and regulating gene expression and various signaling pathways. We aim to establish the development status and neuroprotective mechanism of phytochemicals that target lncRNAs through a thorough literature review. A total of 369 articles were retrieved through manual and electronic searches of PubMed, Web of Science, Scopus and CNKI databases from inception to September 2022. The search utilized combinations of natural products, lncRNAs, neurological disorders, and neuroprotective effects as keywords. The included studies, a total of 31 preclinical trials, were critically reviewed to present the current situation and the progress in phytochemical-targeted lncRNAs in neuroprotection. Phytochemicals have demonstrated neuroprotective effects in preclinical studies of various neurological disorders by regulating lncRNAs. These disorders include arteriosclerotic ischemia-reperfusion injury, ischemic/hemorrhagic stroke, Alzheimer's disease, Parkinson's disease, glioma, peripheral nerve injury, post-stroke depression, and depression. Several phytochemicals exert neuroprotective roles through mechanisms such as anti-inflammatory, antioxidant, anti-apoptosis, autophagy regulation, and antagonism of Aβ-induced neurotoxicity. Some phytochemicals targeted lncRNAs and served a neuroprotective role by regulating microRNA and mRNA expression. The emergence of lncRNAs as pathological regulators provides a novel direction for the study of phytochemicals in CHM. Elucidating the mechanism of phytochemicals regulating lncRNAs will help to identify new therapeutic targets and promote their application in precision medicine.

THC and CBD: Villain versus Hero? Insights into Adolescent Exposure

Cannabis is the most used drug of abuse worldwide. It is well established that the most abundant phytocannabinoids in this plant are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). These two compounds have remarkably similar chemical structures yet vastly different effects in the brain. By binding to the same receptors, THC is psychoactive, while CBD has anxiolytic and antipsychotic properties. Lately, a variety of hemp-based products, including CBD and THC, have become widely available in the food and health industry, and medical and recreational use of cannabis has been legalized in many states/countries. As a result, people, including youths, are consuming CBD because it is considered “safe”. An extensive literature exists evaluating the harmful effects of THC in both adults and adolescents, but little is known about the long-term effects of CBD exposure, especially in adolescence. The aim of this review is to collect preclinical and clinical evidence about the effects of cannabidiol.

Phytotherapeutic alternatives for neurodegenerative dementias: Scientific review, discussion and therapeutic proposal

The incidence and prevalence of age-related neurodegenerative dementias have been increasing. There is no curative therapy and conventional drug treatment can cause problems for patients. Medicinal plants traditionally used for problems associated with ageing are emerging as a therapeutic resource. The main aim is to give a proposal for use and future research based on scientific knowledge and tradition. A literature search was conducted in several searchable databases. The keywords used were related to neurodegenerative dementias, ageing and medicinal plants. Boolean operators and filters were used to focus the search. As a result, there is current clinical and preclinical scientific information on 49 species used in traditional medicine for ageing-related problems, including neurodegenerative dementias. There are preclinical and clinical scientific evidences on their properties against protein aggregates in the central nervous system and their effects on neuroinflammation, apoptosis dysregulation, mitochondrial dysfunction, gabaergic, glutamatergic and dopaminergic systems alterations, monoamine oxidase alterations, serotonin depletion and oestrogenic protection. In conclusion, the potential therapeutic effect of the different medicinal plants depends on the type of neurodegenerative dementia and its stage of development, but more clinical and preclinical research is needed to find better, safer and more effective treatments.

Current Advances of Plant-Based Vaccines for Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) are characterized by the progressive degeneration and/or loss of neurons belonging to the central nervous system, and represent one of the major global health issues. Therefore, a number of immunotherapeutic approaches targeting the non-functional or toxic proteins that induce neurodegeneration in NDDs have been designed in the last decades. In this context, due to unprecedented advances in genetic engineering techniques and molecular farming technology, pioneering plant-based immunogenic antigen expression systems have been developed aiming to offer reliable alternatives to deal with important NDDs, including Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Diverse reports have evidenced that plant-made vaccines trigger significant immune responses in model animals, supported by the production of antibodies against the aberrant proteins expressed in the aforementioned NDDs. Moreover, these immunogenic tools have various advantages that make them a viable alternative for preventing and treating NDDs, such as high scalability, no risk of contamination with human pathogens, cold chain free production, and lower production costs. Hence, this article presents an overview of the current progress on plant-manufactured vaccines for NDDs and discusses its future prospects.

Targeting Mitochondrial Dysfunction in Neurodegenerative Diseases: Expanding the Therapeutic Approaches by Plant-Derived Natural Products

Mitochondria are the primary source of energy production in neurons, supporting the high energy consumption of the nervous system. Inefficient and dysfunctional mitochondria in the central nervous system have been implicated in neurodegenerative diseases. Therefore, targeting mitochondria offers a new therapeutic opportunity for neurodegenerative diseases. Many recent studies have proposed that plant-derived natural products, as pleiotropic, safe, and readily obtainable sources of new drugs, potentially treat neurodegenerative diseases by targeting mitochondria. In this review, we summarize recent advances in targeting mitochondria in neurotherapeutics by employing plant-derived natural products. We discuss the mechanism of plant-derived natural products according to their mechanism of action on mitochondria in terms of regulating biogenesis, fusion, fission, bioenergetics, oxidative stress, calcium homeostasis, membrane potential, and mitochondrial DNA stability, as well as repairing damaged mitochondria. In addition, we discuss the potential perspectives and challenges in developing plant-derived natural products to target mitochondria, highlighting the clinical value of phytochemicals as feasible candidates for future neurotherapeutics.

Computer-Aided Screening and Revealing Action Mechanism of Green Tea Polyphenols Intervention in Alzheimer's Disease

The accumulation of cross-β-sheet amyloid fibrils is a hallmark of the neurodegenerative process of Alzheimer's disease (AD). Although it has been reported that green tea substances such as epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG) could alleviate the symptoms of AD and other neurodegenerative diseases, the pharmacological mechanism remains largely unexplored. This study aimed to reveal the underlying mechanism of EC, ECG, EGC and EGCG in AD using a computer-aided screening strategy. Our results showed that the four tea polyphenols interfered with the signaling pathways of AD via calcium signaling channels, neurodegeneration-multiple disease signal pathways and others. We also identified the key residues of the interaction between VEGFA and the four active components, which included Glu64 and Phe36. Overall, we have provided valuable insights into the molecular mechanism of tea polyphenols, which could be used as a reference to improve therapeutic strategies against AD.

Phytochemical Composition and Antioxidant Activity of Edible Wild Fruits from Malawi

The purpose of this study was to investigate the phytochemical composition and antioxidant activity of 17 edible wild fruits that are widely distributed and consumed in Malawi for pharmacological value exploration. Qualitative phytochemical analysis, total phenolic content, total flavonoid content, ferric reducing antioxidant power (FRAP), total antioxidant activity (TAA), and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (DPPH) were performed in aqueous and methanolic fruit extracts. The results showed that the extracts contained alkaloids, saponins, terpenoids, glycosides, coumarins, phenolic compounds, tannins, flavonoids, steroids, and quinones. Piliostigma thonningii had the highest total phenolic content ( $1675.33\pm 12.34$  mg GAEg-1 FW) in methanolic extracts, and Annona senegalensis gave the highest levels of total flavonoid content ( $649.67\pm 2.08$  mg RE g-1 FW) in aqueous extracts. The results of antioxidant activities (FRAP, TAA, and DPPH) varied widely, and the variations were significant ( $P<0.05$ ). Thespesia garckeana and Mangifera indica exhibited a high ability to chelate metal cations in methanolic extracts and in aqueous extracts, respectively. DPPH levels were higher in aqueous extracts and ranged from 11.07% to 99.61%. This study provides evidence that the studied edible fruits of Malawi have potential as value-added products for various treatments of oxidative stress-associated ailments as they contain more phytochemical constituents. We recommend further studies to determine if the presence of a particular class of phytochemicals would translate into the bioactivity capability of these edible fruits.

α-Synuclein and Mechanisms of Epigenetic Regulation

Synucleinopathies are a group of neurodegenerative diseases with common pathological lesions associated with the excessive accumulation and abnormal intracellular deposition of toxic species of α-synuclein. The shared clinical features are chronic progressive decline of motor, cognitive, and behavioral functions. These disorders include Parkinson's disease, dementia with Lewy body, and multiple system atrophy. Vigorous research in the mechanisms of pathology of these illnesses is currently under way to find disease-modifying treatment and molecular markers for early diagnosis. α-Synuclein is a prone-to-aggregate, small amyloidogenic protein with multiple roles in synaptic vesicle trafficking, neurotransmitter release, and intracellular signaling events. Its expression is controlled by several mechanisms, one of which is epigenetic regulation. When transmitted to the nucleus, α-synuclein binds to DNA and histones and participates in epigenetic regulatory functions controlling specific gene transcription. Here, we discuss the various aspects of α-synuclein involvement in epigenetic regulation in health and diseases.

Effect of Mucuna pruriens on brain NMDA receptor and tau protein gene expression in cerebral ischemic rats

Present study aimed to assess effect of pre-treatment with Mucuna pruriens seed extract and its bioactive molecule(s) on NMDAR and Tau protein gene expression in cerebral ischemic rodent model. Methanol extract of M. pruriens seeds was characterized by HPLC, and β-sitosterol was isolated by flash chromatography. In vivo studies to observe the effect of pre-treatment (28 days) with methanol extract of M. pruriens seed and β-sitosterol on the unilateral cerebral ischemic rat model. Cerebral ischemia induced by left common carotid artery occlusion (LCCAO) for 75 min (on day 29) followed by reperfusion for 12 h. Rats (n = 48) divided into four groups. GroupI (control,Untreated + LCCAO)-No pre-treatment + cerebral ischemia; GroupII(β-sitosterol + Sham)-pre-treatment with β-sitosterol, 10 mg/kg/day + sham-operated; GroupIII(β-sitosterol + LCCAO)-pre-treatment with β-sitosterol, 10 mg/kg/day + cerebral ischemia; GroupIV(methanol extract + LCCAO)-pre-treatment with methanol extract of M. pruriens seeds, 50 mg/kg/day + cerebral ischemia. Neurological deficit score was assessed just before sacrifice. Experimental animals were sacrificed after 12 h reperfusion. Brain histopathology was performed. Gene expression of NMDAR and Tau protein of left cerebral hemisphere (occluded side) was performed by RT-PCR. Results revealed that the neurological deficit score was lower in groups III and IV compared to group I. NMDAR and tau protein mRNA expression in left cerebral hemisphere were upregulated in Group I, downregulated in groups III and IV. Histopathology of left cerebral hemisphere (occluded side) in Group I showed features of ischemic brain damage. Groups III and IV, left cerebral hemisphere showed less ischemic damage compared GroupI. Right cerebral hemisphere showed no areas of ischemia-induced brain changes. Pre-treatment with β-sitosterol and methanol extract of M. pruriens seeds may reduce ischemic brain injury following unilateral common carotid artery occlusion in rats.

Synucleins: New Data on Misfolding, Aggregation and Role in Diseases

The synucleins are a family of natively unfolded (or intrinsically unstructured) proteins consisting of α-, β-, and γ-synuclein involved in neurodegenerative diseases and cancer. The current number of publications on synucleins has exceeded 16.000. They remain the subject of constant interest for over 35 years. Two reasons explain this unchanging attention: synuclein's association with several severe human diseases and the lack of understanding of the functional roles under normal physiological conditions. We analyzed recent publications to look at the main trends and developments in synuclein research and discuss possible future directions. Traditional areas of peak research interest which still remain high among last year's publications are comparative studies of structural features as well as functional research on of three members of the synuclein family. Another popular research topic in the area is a mechanism of α-synuclein accumulation, aggregation, and fibrillation. Exciting fast-growing area of recent research is α-synuclein and epigenetics. We do not present here a broad and comprehensive review of all directions of studies but summarize only the most significant recent findings relevant to these topics and outline potential future directions.

Interactions between Major Bioactive Polyphenols of Sugarcane Top: Effects on Human Neural Stem Cell Differentiation and Astrocytic Maturation

Sugarcane (Saccharum officinarum L.) is a tropical plant grown for sugar production. We recently showed that sugarcane top (ST) ameliorates cognitive decline in a mouse model of accelerated aging via promoting neuronal differentiation and neuronal energy metabolism and extending the length of the astrocytic process in vitro. Since the crude extract consists of multicomponent mixtures, it is crucial to identify bioactive compounds of interest and the affected molecular targets. In the present study, we investigated the bioactivities of major polyphenols of ST, namely 3-O-caffeoylquinic acid (3CQA), 5-O-caffeoylquinic acid (5CQA), 3-O-feruloylquinic acid (3FQA), and Isoorientin (ISO), in human fetal neural stem cells (hNSCs)- an in vitro model system for studying neural development. We found that multiple polyphenols of ST contributed synergistically to stimulate neuronal differentiation of hNSCs and induce mitochondrial activity in immature astrocytes. Mono-CQAs (3CQA and 5CQA) regulated the expression of cyclins related to G1 cell cycle arrest, whereas ISO regulated basic helix-loop-helix transcription factors related to cell fate determination. Additionally, mono-CQAs activated p38 and ISO inactivated GSK3β. In hNSC-derived immature astrocytes, the compounds upregulated mRNA expression of PGC-1α, a master regulator of astrocytic mitochondrial biogenesis. Altogether, our findings suggest that synergistic interactions between major polyphenols of ST contribute to its potential for neuronal differentiation and astrocytic maturation.

Integrating nutriepigenomics in Parkinson's disease management: New promising strategy in the omics era

Parkinson's disease (PD) is the most prevalent brain motor disorder and is frequently regarded as an idiopathic and sporadic disease due to its unclear etiology. Although the pathological mechanisms of PD have already been investigated at various omics levels, no disease-modifying drugs are currently available. At the moment, treatments can only provide symptomatic relief to control or improve motor symptoms. Parkinson's disease is a multifactorial disease, the development and progression of which are influenced by multiple factors, including the genetic markups and the environment. As an indispensable component of our daily life, nutrition is considered one of the most robust environmental factors affecting our health. Consequently, depending on our dietary habits, nutrition can either induce or reduce our susceptibility to PD. Epigenetic mechanisms regulate gene expression through DNA methylation, histone modifications, and non-coding RNAs (ncRNAs) activity. Accumulating evidence from nutriepigenomics studies has reported altered epigenetic mechanisms in clinical and pre-clinical PD models, and the potential role of nutrition in modifying the changes. In addition, through nutrigenetics and nutrigenomics studies, the diet-gene, and gene-diet interactions concerning PD development and progression have been investigated. Herein, current findings on the roles of nutrition in epigenetic mechanisms underpinning PD development and progression are discussed. Recent advancements in the multi-omics approach in PD nutrition research are also underlined. The ability of nutrients to influence epigenetic mechanisms and the availability of multi-omics applications compel the immediate use of personalized nutrition as adjuvant therapy for PD.

Simultaneous measurement of the size and methylation of chromosome 4qA-D4Z4 repeats in facioscapulohumeral muscular dystrophy by long-read sequencing

Background

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular disorder characterized by asymmetric muscle wasting and weakness. FSHD can be subdivided into two types: FSHD1, caused by contraction of the D4Z4 repeat on chromosome 4q35, and FSHD2, caused by mild contraction of the D4Z4 repeat plus aberrant hypomethylation mediated by genetic variants in SMCHD1, DNMT3B, or LRIF1. Genetic diagnosis of FSHD is challenging because of the complex procedures required.

Methods

We applied Nanopore CRISPR/Cas9-targeted resequencing for the diagnosis of FSHD by simultaneous detection of D4Z4 repeat length and methylation status at nucleotide level in genetically-confirmed and suspected patients.

Results

We found significant hypomethylation of contracted 4q-D4Z4 repeats in FSHD1, and both 4q- and 10q-D4Z4 repeats in FSHD2. We also found that the hypomethylation in the contracted D4Z4 in FSHD1 is moderately correlated with patient phenotypes.

Conclusions

Our method contributes to the development for the diagnosis of FSHD using Nanopore long-read sequencing. This finding might give insight into the mechanisms by which repeat contraction causes disease pathogenesis.

Differential effects of the recombinant type 1 ribosome-inactivating protein, OsRIP1, on growth of PSB-D and BY-2 cells

Plant suspension cells were treated with recombinant OsRIP1, a type 1 ribosome-inactivating protein (RIP) from rice (Oryza sativa L.). OsRIP1 triggered cell death in tobacco BY-2 cells but not in Arabidopsis PSB-D cells. Phenotypic changes in BY-2 cells exposed to OsRIP1, included loss of growth capacity, loss of integrity of the plasma membrane and vacuolar collapse. These effects were also accompanied by RNA degradation and DNA fragmentation. Targeting of exogenous OsRIP1 to plant vacuoles and OsRIP1-induced accumulation of transcripts for vacuolar processing enzymes (VPEs) indicated that OsRIP1 provoked plant cell death in tobacco BY-2 cells through the activation of VPEs and subsequent vacuolar disruption, which was probably independent of its N-glycosylase activity on cytosolic ribosomes. Necrosis with limited production of H₂O₂ was observed after infiltration of high concentrations of OsRIP1 in epidermal cells of Nicotiana tabacum cv. Samsun NN plants. Our study provides the first evidence that OsRIP1 exerts differential effects on the growth of PSB-D and BY-2 cells. The vacuole-dependent cell death pathway is associated with the lethal effect of the exogenously applied OsRIP1 on BY-2 cells.

Carrageenophyte Kappaphycus malesianus Inhibits Microglia-Mediated Neuroinflammation via Suppression of AKT/NF-κB and ERK Signaling Pathways

Neuroinflammation is an inflammatory response in any part of the central nervous system triggered by the activation of microglia and astrocytes to produce proinflammatory cytokines in the brain. However, overproduction of proinflammatory cytokines further contributes to the development of neurodegenerative disorders. Red seaweed, Kappaphycus malesianus, is a predominant carrageenophyte commercially cultivated in Semporna, Sabah, Malaysia. It is an important source of raw material for kappa-carrageenan productions in the food, pharmaceutical and cosmetics industries. However, no studies have been conducted focusing on the antineuroinflammatory effects of K. malesianus. The aim of the present study was to investigate the effect of the antineuroinflammatory activity of K. malesianus extracts (ethyl acetate, ethanol and methanol) on lipopolysaccharide-stimulated BV2 microglia and the underlying mechanisms involved in the regulation of neuroinflammatory pathways. Extract with the most promising antineuroinflammatory activity was analyzed using liquid chromatography-mass spectrometry (LC-MS). Our results show that methanol extract has a convincing antineuroinflammatory effect by suppressing both AKT/NF-κB and ERK signaling pathways to inhibit the expression of all proinflammatory cytokines without causing a cytotoxicity effect. LC-MS analysis of methanol extract revealed two compounds: prosopinine and eplerenone. Our findings indicated that metabolites of K. malesianus are potent antineuroinflammatory agents with respect to prevention of neurological disorders.

Formulated Curcumin Prevents Paclitaxel-Induced Peripheral Neuropathy through Reduction in Neuroinflammation by Modulation of α7 Nicotinic Acetylcholine Receptors

Paclitaxel is widely used in the treatment of various types of solid malignancies. Paclitaxel-induced peripheral neuropathy (PIPN) is often characterized by burning pain, cold, and mechanical allodynia in patients. Currently, specific pharmacological treatments against PIPN are lacking. Curcumin, a polyphenol of Curcuma longa, shows antioxidant, anti-inflammatory, and neuroprotective effects and has recently shown efficacy in the mitigation of various peripheral neuropathies. Here, we tested, for the first time, the therapeutic effect of 1.5% dietary curcumin and Meriva (a lecithin formulation of curcumin) in preventing the development of PIPN in C57BL/6J mice. Curcumin or Meriva treatment was initiated one week before injection of paclitaxel and continued throughout the study (21 days). Mechanical and cold sensitivity as well as locomotion/motivation were tested by the von Frey, acetone, and wheel-running tests, respectively. Additionally, sensory-nerve-action-potential (SNAP) amplitude by caudal-nerve electrical stimulation, electronic microscopy of the sciatic nerve, and inflammatory-protein quantification in DRG and the spinal cord were measured. Interestingly, a higher concentration of curcumin was observed in the spinal cord with the Meriva diet than the curcumin diet. Our results showed that paclitaxel-induced mechanical hypersensitivity was partially prevented by the curcumin diet but completely prevented by Meriva. Both the urcumin diet and the Meriva diet completely prevented cold hypersensitivity, the reduction in SNAP amplitude and reduced mitochondrial pathology in sciatic nerves observed in paclitaxel-treated mice. Paclitaxel-induced inflammation in the spinal cord was also prevented by the Meriva diet. In addition, an increase in α7 nAChRs mRNA, known for its anti-inflammatory effects, was also observed in the spinal cord with the Meriva diet in paclitaxel-treated mice. The use of the α7 nAChR antagonist and α7 nAChR KO mice showed, for the first time in vivo, that the anti-inflammatory effects of curcumin in peripheral neuropathy were mediated by these receptors. The results presented in this study represent an important advance in the understanding of the mechanism of action of curcumin in vivo. Taken together, our results show the therapeutic potential of curcumin in preventing the development of PIPN and further confirms the role of α7 nAChRs in the anti-inflammatory effects of curcumin.

Mucuna pruriens Seed Aqueous Extract Improved Neuroprotective and Acetylcholinesterase Inhibitory Effects Compared with Synthetic L-Dopa

L-dopa, a dopaminergic agonist, is the gold standard for the treatment of Parkinson’s disease. However, due to the long-term toxicity and adverse effects of using L-dopa as the first-line therapy for Parkinson’s disease, a search for alternative medications is an important current challenge. Traditional Ayurvedic medicine has suggested the use of Mucuna pruriens Linn. (Fabaceae) as an anti-Parkinson’s agent. The present study aimed to quantify the amount of L-dopa in M. pruriens seed extract by HPLC analysis. The cytotoxicity and neuroprotective properties of M. pruriens aqueous extract were investigated by two in vitro models including the serum deprivation method and co-administration of hydrogen peroxide assay. The results showed the significant neuroprotective activities of M. pruriens seed extracts at a concentration of 10 ng/mL. In addition, the effects of L-dopa and M. pruriens seed extract on in vitro acetylcholinesterase activities were studied. M. pruriens seed extract demonstrated acetylcholinesterase inhibitory activity, while synthetic L-dopa enhanced the activity of the enzyme. It can be concluded that the administration of M. pruriens seed might be effective in protecting the brain against neurodegenerative disorders such as Parkinson’s and Alzheimer’s diseases. M. prurience seed extract containing L-dopa has shown less acetylcholinesterase activity stimulation compared with L-dopa, suggesting that the extract might have a superior benefit for use in the treatment of Parkinson’s disease.

Circulating Human Serum Metabolites Derived from the Intake of a Saffron Extract (Safr'InsideTM) Protect Neurons from Oxidative Stress: Consideration for Depressive Disorders

Increases in oxidative stress have been reported to play a central role in the vulnerability to depression, and antidepressant drugs may reduce increased oxidative stress in patients. Among the plants exerting anti-inflammatory and anti-oxidant properties, saffron, a spice derived from the flower of Crocus sativus, is also known for its positive effects on depression, potentially through its SSRI-like properties. However, the molecular mechanisms underlying these effects and their health benefits for humans are currently unclear. Using an original ex vivo clinical approach, we demonstrated for the first time that the circulating human metabolites produced following saffron intake (Safr’Inside^TM) protect human neurons from oxidative-stress-induced neurotoxicity by preserving cell viability and increasing BNDF production. In particular, the metabolites significantly stimulated both dopamine and serotonin release. In addition, the saffron’s metabolites were also able to protect serotonergic tone by inhibiting the expression of the serotonin transporter SERT and down-regulating serotonin metabolism. Altogether, these data provide new biochemical insights into the mechanisms underlying the beneficial impact of saffron on neuronal viability and activity in humans, in the context of oxidative stress related to depression.

The Protective Effect of a Unique Mix of Polyphenols and Micronutrients against Neurodegeneration Induced by an In Vitro Model of Parkinson’s Disease

Parkinson’s disease (PD) is second-most common disabling neurological disorder worldwide, and unfortunately, there is not yet a definitive way to prevent it. Polyphenols have been widely shown protective efficacy against various PD symptoms. However, data on their effect on physio-pathological mechanisms underlying this disease are still lacking. In the present work, we evaluated the activity of a mixture of polyphenols and micronutrients, named A5⁺, in the murine neuroblastoma cell line N1E115 treated with 6-Hydroxydopamine (6-OHDA), an established neurotoxic stimulus used to induce an in vitro PD model. We demonstrate that a pretreatment of these cells with A5⁺ causes significant reduction of inflammation, resulting in a decrease in pro-inflammatory cytokines (IFN-γ, IL-6, TNF-α, and CXCL1), a reduction in ROS production and activation of extracellular signal-regulated kinases (ERK)1/2, and a decrease in apoptotic mechanisms with the related increase in cell viability. Intriguingly, A5⁺ treatment promoted cellular differentiation into dopaminergic neurons, as evident by the enhancement in the expression of tyrosine hydroxylase, a well-established dopaminergic neuronal marker. Overall, these results demonstrate the synergic and innovative efficacy of A5⁺ mixture against PD cellular pathological processes, although further studies are needed to clarify the mechanisms underlying its beneficial effect.

Ginsenoside Rg1 Plays a Neuroprotective Role in Regulating the Iron-Regulated Proteins and Against Lipid Peroxidation in Oligodendrocytes

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Progressive loss of dopaminergic neurons in the substantia nigra (SN) is one of the major pathological changes. However, the reasons for the dopaminergic neuron loss are still ambiguous and further studies are needed to evaluate the in-depth mechanisms of neuron death. Oxidative stress is a significant factor causing neuronal damage. Dopaminergic neurons in the SN are susceptible to oxidative stress, which is closely associated with iron dyshomeostasis in the brain. Ginsenoside Rg1 from ginseng plays a crucial role in neuroprotective effects through anti-inflammation and attenuating the aggregation of abnormal α-synuclein. In our study, we established a chronic PD mouse model by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine combined with probenecid and explored the effect of Rg1 on the oxidative stress and brain iron homeostasis. Rg1 was verified to improve the level of tyrosine hydroxylase and anti-oxidant stress. In addition, Rg1 maintained the iron-regulated protein homeostasis by increasing the expression of ferritin heavy chain and decreasing ferritin light chain in oligodendrocytes, especially the mature oligodendrocytes (OLs). Furthermore, Rg1 had a positive effect on the myelin sheath protection and increased the number of mature oligodendrocytes, proved by the increased staining of myelin basic protein and CC-1. In conclusion, Rg1 could play a neuroprotective role through remitting the iron-regulated protein dyshomeostasis by ferritin and against lipid peroxidation stress in oligodendrocytes.

Therapeutic promise of carotenoids as antioxidants and anti-inflammatory agents in neurodegenerative disorders

Neurodegenerative disorders (NDs) including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis have various disease-specific causal factors and pathological features. A very common characteristic of NDs is oxidative stress (OS), which takes place due to the elevated generation of reactive oxygen species during the progression of NDs. Furthermore, the pathological condition of NDs including an increased level of protein aggregates can further lead to chronic inflammation because of the microglial activation. Carotenoids (CTs) are naturally occurring pigments that play a significant role in averting brain disorders. More than 750 CTs are present in nature, and they are widely available in plants, microorganisms, and animals. CTs are accountable for the red, yellow, and orange pigments in several animals and plants, and these colors usually indicate various types of CTs. CTs exert various bioactive properties because of its characteristic structure, including anti-inflammatory and antioxidant properties. Due to the protective properties of CTs, levels of CTs in the human body have been markedly linked with the prevention and treatment of multiple diseases including NDs. In this review, we have summarized the relationship between OS, neuroinflammation, and NDs. In addition, we have also particularly focused on the antioxidants and anti-inflammatory properties of CTs in the management of NDs.

Novel Findings regarding the Bioactivity of the Natural Blue Pigment Genipin in Human Diseases

Genipin is an important monoterpene iridoid compound isolated from Gardenia jasminoides J.Ellis fruits and from Genipa americana fruits, or genipap. It is a precursor of a blue pigment which may be attractive alternative to existing food dyes and it possesses various potential therapeutic properties such as anti-cancer, anti-diabetic and hepatoprotective activity. Biomedical studies also show that genipin may act as a neuroprotective drug. This review describes new aspects of the bioactivity of genipin against various diseases, as well as its toxicity and industrial applications, and presents its potential mechanism of action.

Molecular Cloning and Identification of NADPH Cytochrome P450 Reductase from Panax ginseng

Ginseng (Panax ginseng C.A. Mey.) is a precious Chinese traditional medicine, for which ginsenosides are the most important medicinal ingredients. Cytochrome P450 enzymes (CYP450) and their primary redox molecular companion NADPH cytochrome P450 reductase (CPR) play a key role in ginsenoside biosynthesis pathway. However, systematic studies of CPR genes in ginseng have not been reported. Numerous studies on ginsenoside synthesis biology still use Arabidopsis CPR (AtCPR1) as a reductase. In this study, we isolated two CPR genes (PgCPR1, PgCPR2) from ginseng adventitious roots. Phylogenetic tree analysis showed that both PgCPR1 and PgCPR2 are grouped in classⅡ of dicotyledonous CPR. Enzyme experiments showed that recombinant proteins PgCPR1, PgCPR2 and AtCPR1 can reduce cytochrome c and ferricyanide with NADPH as the electron donor, and PgCPR1 had the highest enzymatic activities. Quantitative real-time PCR analysis showed that PgCPR1 and PgCPR2 transcripts were detected in all examined tissues of Panax ginseng and both showed higher expression in stem and main root. Expression levels of the PgCPR1 and PgCPR2s were both induced after a methyl jasmonate (MeJA) treatment and its pattern matched with ginsenoside accumulation. The present investigation suggested PgCPR1 and PgCPR2 are associated with the biosynthesis of ginsenoside. This report will assist in future CPR family studies and ultimately improving ginsenoside production through transgenic engineering and synthetic biology.

Case Report: Synucleinopathy Associated With Phalaris Neurotoxicity in Sheep

Chronic intoxication with tryptamine-alkaloid-rich Phalaris species (spp.) pasture plants is known colloquially as Phalaris staggers syndrome, a widely occurring neurological disorder of sheep, cattle, horses, and kangaroos. Of comparative interest, structurally analogous tryptamine-alkaloids cause experimental parkinsonism in primates. This study aimed to investigate the neuropathological changes associated with spontaneous cases of Phalaris staggers in sheep with respect to those encountered in human synucleinopathy. In sheep affected with Phalaris staggers, histological, immunohistochemical, and immunofluorescence analysis revealed significant accumulation of neuromelanin and aggregated α-synuclein in the perikaryon of neurons in the cerebral cortex, thalamus, brainstem, and spinal cord. Neuronal intracytoplasmic Lewy bodies inclusions were not observed in these cases of ovine Phalaris staggers. These important findings established a clear link between synucleinopathy and the neurologic form of Phalaris plant poisoning in sheep, demonstrated in six of six affected sheep. Synucleinopathy is a feature of a number of progressive and fatal neurodegenerative disorders of man and may be a common endpoint of such disorders, which in a variety of ways perturb neuronal function. However, whether primary to the degenerative process or a consequence of it awaits clarification in an appropriate model system.

The Multifaceted Roles of Proline in Cell Behavior

Herein, we review the multifaceted roles of proline in cell biology. This peculiar cyclic imino acid is: (i) A main precursor of extracellular collagens (the most abundant human proteins), antimicrobial peptides (involved in innate immunity), salivary proteins (astringency, teeth health) and cornifins (skin permeability); (ii) an energy source for pathogenic bacteria, protozoan parasites, and metastatic cancer cells, which engage in extracellular-protein degradation to invade their host; (iii) an antistress molecule (an osmolyte and chemical chaperone) helpful against various potential harms (UV radiation, drought/salinity, heavy metals, reactive oxygen species); (iv) a neural metabotoxin associated with schizophrenia; (v) a modulator of cell signaling pathways such as the amino acid stress response and extracellular signal-related kinase pathway; (vi) an epigenetic modifier able to promote DNA and histone hypermethylation; (vii) an inducer of proliferation of stem and tumor cells; and (viii) a modulator of cell morphology and migration/invasiveness. We highlight how proline metabolism impacts beneficial tissue regeneration, but also contributes to the progression of devastating pathologies such as fibrosis and metastatic cancer.

Mitochondrial Dysfunction and Endoplasmic Reticulum Stress in Age Related Macular Degeneration, Role in Pathophysiology, and Possible New Therapeutic Strategies

Age related macular degeneration (AMD) is the main cause of legal blindness in developed countries. It is a multifactorial disease in which a combination of genetic and environmental factors contributes to increased risk of developing this vision-incapacitating condition. Oxidative stress plays a central role in the pathophysiology of AMD and recent publications have highlighted the importance of mitochondrial dysfunction and endoplasmic reticulum stress in this disease. Although treatment with vascular endothelium growth factor inhibitors have decreased the risk of blindness in patients with the exudative form of AMD, the search for new therapeutic options continues to prevent the loss of photoreceptors and retinal pigment epithelium cells, characteristic of late stage AMD. In this review, we explain how mitochondrial dysfunction and endoplasmic reticulum stress participate in AMD pathogenesis. We also discuss a role of several antioxidants (bile acids, resveratrol, melatonin, humanin, and coenzyme Q10) in amelioration of AMD pathology.

Neuroprotective Activities of Crossyne flava Bulbs and Amaryllidaceae Alkaloids: Implications for Parkinson's Disease

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases and affects approximately 6.3 million people worldwide. To date, the treatment of PD remains a challenge, as available treatment options are known to be associated with serious side effects; hence, the search for new treatment strategies is critical. Extracts from the Amaryllidaceae plant family as well as their alkaloids have been reported to have neuroprotective potentials. This study, therefore, investigated the biological activities of Crossyne flava and its isolated alkaloids in an in vitro MPP⁺ (1-methyl-4-phenylpyridinium) PD model using SH-SY5Y cells. The effects of the total extract as well as the four compounds isolated from Crossyne flava (i.e., pancratinine B (1), bufanidrine (2), buphanisine (3), and epibuphanisine (4)) were evaluated for cell viability, neuroprotection, levels of reactive oxygen species (ROS), adenosine triphosphate activity (ATP), and caspase 3/7 activity in SH-SY5Y cells. The results obtained showed that pre-treatment with both the extract and the isolated compounds was effective in protecting the SH-SY5Y cells from MPP⁺-induced neurotoxicity and inhibited ROS generation, ATP depletion as well as apoptosis induction in the SH-SY5Y cells. The results of this study show that the Amaryllidaceae plant family may be a source of novel compounds for the treatment of neurodegenerative diseases, which validates the reported traditional uses.