Gallic and vanillic acid suppress inflammation and promote myelination in an in vitro mouse model of neurodegeneration

From the gut to the brain: the long journey of phenolic compounds with neurocognitive effects

The human gut microbiota is a complex community of micro-organisms that play a crucial role in maintaining overall health. Recent research has shown that gut microbes also have a profound impact on brain function and cognition, leading to the concept of the gut-brain axis. One way in which the gut microbiota can influence the brain is through the bioconversion of polyphenols to other bioactive molecules. Phenolic compounds are a group of natural plant metabolites widely available in the human diet, which have anti-inflammatory and other positive effects on health. Recent studies have also suggested that some gut microbiota-derived phenolic metabolites may have neurocognitive effects, such as improving memory and cognitive function. The specific mechanisms involved are still being studied, but it is believed that phenolic metabolites may modulate neurotransmitter signaling, reduce inflammation, and enhance neural plasticity. Therefore, to exert a protective effect on neurocognition, dietary polyphenols or their metabolites must reach the brain, or act indirectly by producing an increase in bioactive molecules such as neurotransmitters. Once ingested, phenolic compounds are subjected to various processes (eg, metabolization by gut microbiota, absorption, distribution) before they cross the blood-brain barrier, perhaps the most challenging stage of their trajectory. Understanding the role of phenolic compounds in the gut-brain axis has important implications for the development of new therapeutic strategies for neurological and psychiatric disorders. By targeting the gut microbiota and its production of phenolic metabolites, it may be possible to improve brain function and prevent cognitive decline. In this article, the current state of knowledge on the endogenous generation of phenolic metabolites by the gut microbiota and how these compounds can reach the brain and exert neurocognitive effects was reviewed.

Effect of bioactive extracts from Eucalyptus globulus leaves in experimental models of Alzheimer's disease

Current therapies for Alzheimer's disease (AD) do not delay its progression, therefore, novel disease-modifying strategies are urgently needed. Recently, an increasing number of compounds from natural origin with protective properties against AD have been identified. Mixtures or extracts obtained from natural products containing several bioactive compounds have multifunctional properties and have drawn the attention because multiple AD pathways can be simultaneously modulated. This study evaluated the in vitro and in vivo effect of the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and an extract obtained from the hydrodistillation residual water (HRW). It was observed that EO and HRW have anti-inflammatory effect in brain immune cells modeling AD, namely lipopolysaccharide (LPS)- and amyloid-beta (Aβ)-stimulated microglia. In cell models that mimic AD-related neuronal dysfunction, HRW attenuated Aβ secretion and Aβ-induced mitochondrial dysfunction. Since the HRW's major components did not cross the blood-brain barrier, both EO and HRW were administered to the APP/PS1 transgenic AD mouse model by an intranasal route, which reduced cortical and hippocampal Aβ levels, and to rescue memory deficits and anxiety-like behaviors. Finally, HRW and EO were found to regulate cholesterol levels in aged mice after intranasal administration, suggesting that these extracts can reduce hypercholesterolemia and avoid risk for AD development. Overall, findings support a protective role of E. globulus extracts against AD‑like pathology and cognitive impairment highlighting the underlying mechanisms. These extracts obtained from underused forest biomass could be useful to develop nutraceutical supplements helpful to avoid AD risk and to prevent its progression.

Effects of Phenolic Acids Produced from Food-Derived Flavonoids and Amino Acids by the Gut Microbiota on Health and Disease

The gut microbiota metabolizes flavonoids, amino acids, dietary fiber, and other components of foods to produce a variety of gut microbiota-derived metabolites. Flavonoids are the largest group of polyphenols, and approximately 7000 flavonoids have been identified. A variety of phenolic acids are produced from flavonoids and amino acids through metabolic processes by the gut microbiota. Furthermore, these phenolic acids are easily absorbed. Phenolic acids generally represent phenolic compounds with one carboxylic acid group. Gut microbiota-derived phenolic acids have antiviral effects against several viruses, such as SARS-CoV-2 and influenza. Furthermore, phenolic acids influence the immune system by inhibiting the secretion of proinflammatory cytokines, such as interleukin-1β and tumor necrosis factor-α. In the nervous systems, phenolic acids may have protective effects against neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Moreover, phenolic acids can improve levels of blood glucose, cholesterols, and triglycerides. Phenolic acids also improve cardiovascular functions, such as blood pressure and atherosclerotic lesions. This review focuses on the current knowledge of the effects of phenolic acids produced from food-derived flavonoids and amino acids by the gut microbiota on health and disease.

Uncovering the protective potential of vanillic acid against traumatic brain injury-induced cognitive decline in male rats: Insights into underlying mechanisms

Traumatic brain injury (TBI) is a significant contributor to global mortality and disability, and there is still no specific drug available to treat cognitive deficits in survivors. Vanillic acid (VA), a bioactive phenolic compound, has shown protective effects in various models of neurodegeneration; however, its impact on TBI outcomes remains elusive. Therefore, this study aimed to elucidate the possible role of VA in ameliorating TBI-induced cognitive decline and to reveal the mechanisms involved. TBI was induced using the Marmarou impact acceleration model to deliver an impact force of 300 g, and treatment with VA (50 mg/kg; P.O.) was initiated 30 minutes post-TBI. The cognitive performance, hippocampal long-term potentiation (LTP), oxidative stress markers, neurological function, cerebral edema, and morphological changes were assessed at scheduled points in time. TBI resulted in cognitive decline in the passive avoidance task, impaired LTP in the perforant path-dentate gyrus (PP-DG) pathway, increased hippocampal oxidative stress, cerebral edema, neurological deficits, and neuronal loss in the rat hippocampus. In contrast, acute VA administration mitigated all the aforementioned TBI outcomes. The data suggest that reducing synaptic plasticity impairment, regulating oxidative and antioxidant defense, alleviating cerebral edema, and preventing neuronal loss by VA can be at least partially attributed to its protection against TBI-induced cognitive decline.

Molecular Insights on Coffee Components as Chemical Antioxidants

Coffee is not only a delicious beverage but also an important dietary source of natural antioxidants. We live in a world where it is impossible to avoid pollution, stress, food additives, radiation, and other sources of oxidants that eventually lead to severe health disorders. Fortunately, there are chemicals in our diet that counteract the hazards posed by the reactive species that trigger oxidative stress. They are usually referred to as antioxidants; some of them can be versatile compounds that exert such a role in many ways. This review summarizes, from a chemical point of view, the antioxidant effects of relevant molecules found in coffee. Their mechanisms of action, trends in activity, and the influence of media and pH in aqueous solutions, are analyzed. Structure-activity relationships are discussed, and the protective roles of these compounds are examined. A particular section is devoted to derivatives of some coffee components, and another one to their bioactivity. The data used in the analysis come from theoretical and computational protocols, which have been proven to be very useful in this context. Hopefully, the information provided here will pro-mote further investigations into the amazing chemistry contained in our morning coffee cup.   Resumen. El café no solo es una bebida deliciosa, sino también una importante fuente dietética de antioxidantes naturales. Vivimos en un mundo donde es imposible evitar la contaminación, el estrés, los aditivos alimentarios, la radiación y otras fuentes de oxidantes que eventualmente conducen a trastornos de salud graves. Afortunadamente, existen sustancias químicas en nuestra dieta que contrarrestan los peligros planteados por las especies reactivas que desencadenan el estrés oxidativo. Por lo general, se les denomina antioxidantes; algunos de ellos pueden ser compuestos versátiles que ejercen dicho papel de muchas maneras. Este artículo de revisión resume, desde un punto de vista químico, los efectos antioxidantes de moléculas relevantes encontradas en el café. Se analizan sus mecanismos de acción, tendencias en la actividad y la influencia del medio y el pH en soluciones acuosas. Se discuten las relaciones estructura-actividad, y se examinan los roles protectores de estos compuestos. Se dedica una sección particular a los derivados de algunos componentes del café, y otra a su bioactividad. Los datos utilizados en el análisis provienen de protocolos teóricos y computacionales, que han demostrado ser muy útiles en este contexto. Se espera que la información proporcionada aquí promueva investigaciones futuras sobre la química contenida en nuestra taza de café matutina.

The Potential Health Benefits of Gallic Acid: Therapeutic and Food Applications

Gallic acid (GA), a phenolic acid found in fruits and vegetables, has been consumed by humans for centuries. Its extensive health benefits, such as antimicrobial, antioxidant, anticancer, anti-inflammatory, and antiviral properties, have been well-documented. GA's potent antioxidant capabilities enable it to neutralize free radicals, reduce oxidative stress, and protect cells from damage. Additionally, GA exerts anti-inflammatory effects by inhibiting inflammatory cytokines and enzymes, making it a potential therapeutic agent for inflammatory diseases. It also demonstrates anticancer properties by inhibiting cancer cell growth and promoting apoptosis. Furthermore, GA offers cardiovascular benefits, such as lowering blood pressure, decreasing cholesterol, and enhancing endothelial function, which may aid in the prevention and management of cardiovascular diseases. This review covers the chemical structure, sources, identification and quantification methods, and biological and therapeutic properties of GA, along with its applications in food. As research progresses, the future for GA appears promising, with potential uses in functional foods, pharmaceuticals, and nutraceuticals aimed at improving overall health and preventing disease. However, ongoing research and innovation are necessary to fully understand its functional benefits, address current challenges, and establish GA as a mainstay in therapeutic and nutritional interventions.

Underlying mechanisms behind the neuroprotective effect of vanillic acid against diabetes-associated cognitive decline: An in vivo study in a rat model

Hippocampal synaptic dysfunction, oxidative stress, neuroinflammation, and neuronal loss play critical roles in the pathophysiology of diabetes-associated cognitive decline (DACD). The study aimed to investigate the effects of vanillic acid (VA), a phenolic compound, against DACD and explore the potential underlying mechanisms. Following confirmation of diabetes, rats were treated with VA (50 mg/kg/day; P.O.) or insulin (6 IU/rat/day; S.C.) for 8 consecutive weeks. The cognitive performance of the rats was evaluated using passive-avoidance and water-maze tasks. Long-term potentiation (LTP) was induced at hippocampal dentate gyrus (DG) synapses in response to high-frequency stimulation (HFS) applied to the perforant pathway (PP) to evaluate synaptic plasticity. Oxidative stress factors, inflammatory markers, and histological changes were evaluated in the rat hippocampus. This study showed that streptozotocin (STZ)-induced diabetes caused cognitive decline that was associated with inhibition of LTP induction, suppression of enzymatic antioxidant activities, enhanced lipid peroxidation, elevated levels of inflammatory proteins, and neuronal loss. Interestingly, chronic treatment with VA alleviated blood glucose levels, improved cognitive decline, ameliorated LTP impairment, modulated oxidative-antioxidative status, inhibited inflammatory response, and prevented neuronal loss in diabetic rats at a level comparable to insulin therapy. The results suggest that the antihyperglycemic, antioxidative, anti-inflammatory, and neuroplastic properties of VA may be the mechanisms behind its neuroprotective effect against DACD.

Chemical Analysis and Biological Activities of Extracts Isolated from Symbiotic L. japonicus Plants

Plants produce a wide variety of secondary metabolites, including compounds with biological activities that could be used for the treatment of human diseases. In the present study, we examined the putative production of bioactive molecules in the legume plant Lotus japonicus, which engages into symbiotic relationships with beneficial soil microorganisms. To monitor the production of secondary metabolites when the plant develops beneficial symbiotic relationships, we performed single and double inoculations with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing Rhizobium bacteria. Plant extracts from non-inoculated and inoculated plants were chemically characterized and tested for anti-proliferative, apoptotic, and anti-inflammatory effects on human HEK-293 cells. Both shoot and root extracts from non-inoculated and inoculated plants significantly reduced the HEK-293 cell viability; however, a stronger effect was observed when the root extracts were tested. Shoot and root extracts from Rhizobium-inoculated plants and shoot extracts from AMF-inoculated plants showed apoptotic effects on human cells. Moreover, both shoot and root extracts from AMF-inoculated plants significantly reduced TNFα-induced NF-κB transcriptional activity, denoting anti-inflammatory activity. These results suggest that symbiotic L. japonicus plants are enriched with metabolites that have interesting biological activities and could be further explored for putative future use in the pharmaceutical sector.

Vanillic Acid Ameliorates Demyelination in a Cuprizone-Induced Multiple Sclerosis Rat Model: Possible Underlying Mechanisms

OBJECTIVE

To investigate the effect of vanillic acid (VA) on a Cuprizone (Cup) demyelinating rat model and the mechanisms behind such effect.

METHODS

Thirty adult male Sprague Dawley (SD) rats were randomly divided into three groups: control, Cuprizone, and VA groups. Cuprizone was administrated at a dose of 450 mg/kg per day orally via gastric gavage for 5 weeks. The nerve conduction velocity (NCV) was studied in an isolated sciatic nerve, and then the sciatic nerve was isolated for histopathological examination, electron microscope examination, immunohistochemical staining, and biochemical and PCR assay. The level of IL17 was detected using ELISA, while the antioxidant genes Nrf2, HO-1 expression at the level of mRNA, expression of the myelin basic protein (MBP), interferon-gamma factor (INF)-γ and tumor necrosis factor (TNF)-α, and apoptotic marker (caspase-3) were measured using immunohistochemistry in the sciatic nerve.

RESULTS

There was a significant reduction in NCV in Cup compared to normal rats (p < 0.001), which was markedly improved in the VA group (p < 0.001). EM and histopathological examination revealed significant demyelination and deterioration of the sciatic nerve fibers with significant improvement in the VA group. The level of IL17 as well as the expression of INF-γ and caspase-3 were significantly increased with a significant reduction in the expression of MBP, Nrf2, and HO-1 in the sciatic nerve (p < 0.01), and VA treatment significantly improved the studied parameters (p < 0.01).

CONCLUSION

The current study demonstrated a neuroprotective effect for VA against the Cup-induced demyelinating rat model. This effect might be precipitated by the inhibition of inflammation, oxidative stress, and apoptosis.

Mediterranean Shrub Species as a Source of Biomolecules against Neurodegenerative Diseases

Neurodegenerative diseases are associated with oxidative stress, due to an imbalance in the oxidation-reduction reactions at the cellular level. Various treatments are available to treat these diseases, although they often do not cure them and have many adverse effects. Therefore, it is necessary to find complementary and/or alternative drugs that replace current treatments with fewer side effects. It has been demonstrated that natural products derived from plants, specifically phenolic compounds, have a great capacity to suppress oxidative stress and neutralize free radicals thus, they may be used as alternative alternative pharmacological treatments for pathological conditions associated with an increase in oxidative stress. The plant species that dominate the Mediterranean ecosystems are characterized by having a wide variety of phenolic compound content. Therefore, these species might be important sources of neuroprotective biomolecules. To evaluate this potential, 24 typical plant species of the Mediterranean ecosystems were selected, identifying the most important compounds present in them. This set of plant species provides a total of 403 different compounds. Of these compounds, 35.7% are phenolic acids and 55.6% are flavonoids. The most relevant of these compounds are gallic, vanillic, caffeic, chlorogenic, p-coumaric, and ferulic acids, apigenin, kaempferol, myricitrin, quercetin, isoquercetin, quercetrin, rutin, catechin and epicatechin, which are widely distributed among the analyzed plant species (in over 10 species) and which have been involved in the literature in the prevention of different neurodegenerative pathologies. It is also important to mention that three of these plant species, Pistacea lentiscus, Lavandula stoechas and Thymus vulgaris, have most of the described compounds with protective properties against neurodegenerative diseases. The present work shows that the plant species that dominate the studied geographic area can provide an important source of phenolic compounds for the pharmacological and biotechnological industry to prepare extracts or isolated compounds for therapy against neurodegenerative diseases.

The Antioxidant Activity of Wild-Growing Plants Containing Phenolic Compounds in Latvia

Ethnobotanical reports from Latvia show that Tanacetum vulgare, Calluna vulgaris, Quercus robur, Artemisa absinthium, and Artemisia vulgaris contain phenolic compounds that have antioxidant properties, which can be beneficial in the treatment and prophylaxis of many diseases. The aim of this study was to characterize the phenolic compounds and antioxidant properties of these plants. Plant extracts were prepared using ethanol or acetone and then freeze-dried. Their total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC) were determined and characterized by HPLC. Their antioxidant properties were determined using a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. C. vulgaris herb and T. vulgare leaf extracts contained the highest amounts of flavonoids, but the bark of Q. robur had mostly tannins and phenolic acids. A. absinthium and A. vulgaris had the lowest amounts of polyphenols. When compared using extraction solvents, all acetone extracts had more TPC, more TFC, and better antioxidant activity. All plants contained chlorogenic acid, which contributes to antioxidant properties. The analysed plant extracts could be used in future studies to develop medicinal products with antioxidant properties.

Proteins and Transcriptional Dysregulation of the Brain Extracellular Matrix in Parkinson's Disease: A Systematic Review

The extracellular matrix (ECM) of the brain is a dynamic structure made up of a vast network of bioactive macromolecules that modulate cellular events. Structural, organizational, and functional changes in these macromolecules due to genetic variation or environmental stressors are thought to affect cellular functions and may result in disease. However, most mechanistic studies to date usually focus on the cellular aspects of diseases and pay less attention to the relevance of the processes governing the dynamic nature of the extracellular matrix in disease pathogenesis. Thus, due to the ECM's diversified biological roles, increasing interest in its involvement in disease, and the lack of sufficient compiled evidence regarding its relationship with Parkinson's disease (PD) pathology, we aimed to compile the existing evidence to boost the current knowledge on the area and provide refined guidance for the future research. Here, in this review, we gathered postmortem brain tissue and induced pluripotent stem cell (iPSC)-related studies from PubMed and Google Scholar to identify, summarize and describe common macromolecular alterations in the expression of brain ECM components in Parkinson's disease (PD). A literature search was conducted up until 10 February 2023. The overall hits from the database and manual search for proteomic and transcriptome studies were 1243 and 1041 articles, respectively. Following a full-text review, 10 articles from proteomic and 24 from transcriptomic studies were found to be eligible for inclusion. According to proteomic studies, proteins such as collagens, fibronectin, annexins, and tenascins were recognized to be differentially expressed in Parkinson's disease. Transcriptomic studies displayed dysregulated pathways including ECM-receptor interaction, focal adhesion, and cell adhesion molecules in Parkinson's disease. A limited number of relevant studies were accessed from our search, indicating that much work remains to be carried out to better understand the roles of the ECM in neurodegeneration and Parkinson's disease. However, we believe that our review will elicit focused primary studies and thus support the ongoing efforts of the discovery and development of diagnostic biomarkers as well as therapeutic agents for Parkinson's disease.

Neurobiological effects of gallic acid: current perspectives

Gallic acid (GA) is a phenolic molecule found naturally in a wide range of fruits as well as in medicinal plants. It has many health benefits due to its antioxidant properties. This study focused on finding out the neurobiological effects and mechanisms of GA using published data from reputed databases. For this, data were collected from various sources, such as PubMed/Medline, Science Direct, Scopus, Google Scholar, SpringerLink, and Web of Science. The findings suggest that GA can be used to manage several neurological diseases and disorders, such as Alzheimer's disease, Parkinson's disease, strokes, sedation, depression, psychosis, neuropathic pain, anxiety, and memory loss, as well as neuroinflammation. According to database reports and this current literature-based study, GA may be considered one of the potential lead compounds to treat neurological diseases and disorders. More preclinical and clinical studies are required to establish GA as a neuroprotective drug.

The Role of Extracellular Matrix in Human Neurodegenerative Diseases

The dense neuropil of the central nervous system leaves only limited space for extracellular substances free. The advent of immunohistochemistry, soon followed by advanced diagnostic tools, enabled us to explore the biochemical heterogeneity and compartmentalization of the brain extracellular matrix in exploratory and clinical research alike. The composition of the extracellular matrix is critical to shape neuronal function; changes in its assembly trigger or reflect brain/spinal cord malfunction. In this study, we focus on extracellular matrix changes in neurodegenerative disorders. We summarize its phenotypic appearance and biochemical characteristics, as well as the major enzymes which regulate and remodel matrix establishment in disease. The specifically built basement membrane of the central nervous system, perineuronal nets and perisynaptic axonal coats can protect neurons from toxic agents, and biochemical analysis revealed how the individual glycosaminoglycan and proteoglycan components interact with these molecules. Depending on the site, type and progress of the disease, select matrix components can either proactively trigger the formation of disease-specific harmful products, or reactively accumulate, likely to reduce tissue breakdown and neuronal loss. We review the diagnostic use and the increasing importance of medical screening of extracellular matrix components, especially enzymes, which informs us about disease status and, better yet, allows us to forecast illness.

Medicine-food herb: Angelica sinensis, a potential therapeutic hope for Alzheimer's disease and related complications

Alzheimer's disease (AD) is a progressive neurodegenerative disease, which has brought a huge burden to the world. The current therapeutic approach of one-molecule-one-target strategy fails to address the issues of AD because of multiple pathological features of AD. Traditionally, the herb of Angelica sinensis (AS) comes from the root of an umbrella plant Angelica sinensis (Oliv.) Diels. As a typical medicine-food herb, studies have shown that AS can alleviate AD and AD-complications by multiple targets through the various foundations of pharmaceutical material and dietary supply basis. Therefore, this review summarizes the pharmacological effects of AS for the treatment of AD and AD-complications for the first time. AS contains many effective components, such as ligustilide, z-ligustilide, n-butylidenephthalide, α-pinene, p-cymene, myrcene, ferulic acid, vanillic acid and coniferyl ferulate. It is found that AS, AS-active compounds and AS-compound recipes mainly treat AD through neuroprotective, anti-inflammation, and anti-oxidant effects, improving mitochondrial dysfunction, anti-neuronal apoptosis, regulating autophagy, regulating intestinal flora and enhancing the central cholinergic system, which shows the multi-component and multi-target effect of AS. The role of dietary supplement components in AS for AD intervention is summarized, including vitamin B₁₂, folic acid, arginine, and oleic acid, which can improve the symptoms of AD. Besides, this review focuses on the safety and toxicity evaluation of AS, which provides a basis for its application. This review will provide further support for the research on AD and the application of medicine-food herb AS in a healthy lifestyle in the future.

Recent insights into astrocytes as therapeutic targets for demyelinating diseases

Astrocytes are a group of glial cells that exhibit great morphological, transcriptional and functional diversity both in the resting brain and in response to injury. In recent years, astrocytes have attracted increasing interest as therapeutic targets for demyelinating diseases. Following a demyelinating insult, astrocytes can adopt a wide spectrum of reactive states, which can exacerbate damage, but may also facilitate oligodendrocyte progenitor cell differentiation and myelin regeneration. In this review, we provide an overview of recent literature on astrocyte-oligodendrocyte interactions in the context of demyelinating diseases. We highlight novel key roles for astrocytes both during demyelination and remyelination with a focus on potential therapeutic strategies to favor a pro-regenerative astrocyte response in (progressive) multiple sclerosis.

Anti-Inflammatory Medicinal Plants of Bangladesh—A Pharmacological Evaluation

Inflammatory diseases are considered major threats to human health worldwide. In Bangladesh, a number of medicinal plants have been used in traditional medicine from time immemorial in the treatment of diverse diseases, including inflammatory disorders. This assignment aims at providing the status of the medicinal plants of Bangladesh which are traditionally used in the management of inflammatory disorders and are investigated for their anti-inflammatory prospects using different preclinical studies and future research directions. The information of medicinal plants assembled in this review was obtained from a literature search of electronic databases such as Google Scholar, PubMed, Scopus, Web of Science and ScienceDirect up to December, 2020 from publications on plants investigated for their anti-inflammatory activities, in which the place of plant sample collection was identified as Bangladesh. Keywords for primary searches were “anti-inflammatory,” “Bangladeshi,” and “medicinal plants.” Criteria followed to include plant species were plants that showed significant anti-inflammatory activities in 1) two or more sets of experiments in a single report, 2) same or different sets of experiments in two or more reports, and, 3) plants which are traditionally used in the treatment of inflammation and inflammatory disorders. In this study, 48 species of medicinal plants have been reviewed which have been used in traditional healing practices to manage inflammatory disorders in Bangladesh. The mechanistic pathways of the in vivo and in vitro study models used for the evaluation of anti-inflammatory properties of plant samples have been discussed. Selected plants were described in further detail for their habitat, anti-inflammatory studies conducted in countries other than Bangladesh, and anti-inflammatory active constituents isolated from these plants if any. Medicinal plants of Bangladesh have immense significance for anti-inflammatory activity and have potential to contribute toward the discovery and development of novel therapeutic approaches to combat diseases associated with inflammation. However, the plants reviewed in this article had chiefly undergone preliminary screening and require substantial investigations including identification of active molecules, understanding the mechanism of action, and evaluation for safety and efficacy to be followed by the formulation of safe and effective drug products.

Ethanolic Fruit Extract of Emblica officinalis Suppresses Neuroinflammation in Microglia and Promotes Neurite Outgrowth in Neuro2a Cells

Inhibiting neuroinflammation and modulating neurite outgrowth could be a promising strategy to prevent neurological disorders. Emblica officinalis (EO) may be a potent agent against them. Although EO extract reportedly has anti-inflammatory properties in macrophages, there is limited knowledge about its neuroprotective activity by suppressing microglia-mediated proinflammatory cytokine production and inducing neurite outgrowth. The present study aimed to elucidate the effect of EO fruit extract on the lipopolysaccharide- (LPS-) induced neuroinflammation using microglial (BV2) and neuroblastoma (Neuro2a) cells. The results demonstrated that, in LPS-treated BV2 cells, EO fruit extract reduced nitric oxide, interleukin-6, and tumor necrotic factor-α production. It also enhanced the neurite length of Neuro2a cells, which was linked to the upregulation of TuJ1 and MAP2 expressions. In conclusion, these findings indicate that the ethanolic extract of EO fruits has promising neuroprotective potential to exhibit antineuroinflammation activity and accelerative effect on neurite outgrowth in vitro. Therefore, EO fruit extract can be considered a novel herbal medicine candidate for managing neuroinflammatory diseases.

Neuroprotective Effects of Glochidion zeylanicum Leaf Extract against H2O2/Glutamate-Induced Toxicity in Cultured Neuronal Cells and Aβ-Induced Toxicity in Caenorhabditis elegans

Simple Summary

Antioxidants that are interrelated in the process of overcoming oxidative-stress-induced toxicity and neurite-outgrowth-inducing activity have become the main targets of neuroprotective therapy. The methanol extract of Glochidion zeylanicum (GZM) exhibits neuroprotective properties that are not only limited against H₂O₂/glutamate/Aβ insults but also promote neurite outgrowth activity. The neuroprotective effects of GZM extract were confirmed in cultured neuronal (HT-22 and Neuro-2a) cells and C. elegans models. To the best of our knowledge, this study is the first to report for the neuroprotective effects of GZM extract, suggesting that G. zeylanicum may be a neuroprotectant applicant for the prevention and alleviation of oxidative stress-induced neurodegenerative disorders, including Alzheimer’s disease. However, additional studies are required to identify the mechanistic pathways involved in neuroprotection and to confirm the efficacy of the extract in more complex model organisms.

Abstract

Oxidative stress plays a crucial role in the development of age-related neurodegenerative diseases. Previously, Glochidion zeylanicum methanol (GZM) extract has been reported to have antioxidant and anti-aging properties. However, the effect of GZM on neuroprotection has not been reported yet; furthermore, the mechanism involved in its antioxidant properties remains unresolved. The study is aimed to demonstrate the neuroprotective properties of GZM extract and their underlying mechanisms in cultured neuronal (HT-22 and Neuro-2a) cells and Caenorhabditis elegans models. GZM extract exhibited protective effects against glutamate/H₂O₂-induced toxicity in cultured neuronal cells by suppressing the intracellular reactive oxygen species (ROS) generation and enhancing the expression of endogenous antioxidant enzymes (SODs, GPx, and GSTs). GZM extract also triggered the expression of SIRT1/Nrf2 proteins and mRNA transcription of antioxidant genes (NQO1, GCLM, and EAAT3) which are the master regulators of cellular defense against oxidative stress. Additionally, GZM extract exhibited protective effects to counteract β-amyloid (Aβ)-induced toxicity in C. elegans and promoted neuritogenesis properties in Neuro-2a cells. Our observations suggest that GZM leaf extract has interesting neuritogenesis and neuroprotective potential and can possibly act as potential contender for the treatment of oxidative stress-induced Alzheimer’s disease (AD) and related neurodegenerative conditions; however, this needs to be studied further in other in vivo systems.

Neuroprotective effects of oolong tea extracts against glutamate-induced toxicity in cultured neuronal cells and β-amyloid-induced toxicity in Caenorhabditis elegans

Oolong tea, a traditional Chinese tea, is especially popular in south China and has a variety of health benefits. However, studies about its neuroprotective and neuroregenerative properties are still limited. This study explored the neuroprotective and neurite outgrowth-promoting properties of oolong tea in cultured neuronal cells (Neuro-2a and HT22) and Caenorhabditis elegans models. Ultra performance liquid chromatography was applied to identify the main natural bioactive compounds in oolong tea. Using Neuro-2a and HT22 cells, we found that oolong tea extracts had a protective effect against glutamate-induced cell death. The extracts reduced intracellular reactive oxygen species accumulation and induced gene expression of cellular antioxidant enzymes such as GPx, GSTs and SODs. These extracts also increased the average neurite length, and GAP-43 and Ten-4 mRNA expression in Neuro-2a cells. Moreover, they had protective effects against Aβ-induced paralysis, chemotaxis deficiency and α-synuclein aggregation in C. elegans. This is the first study showing the neuroregenerative and neuroprotective potential of the oolong tea extracts against glutamate/Aβ/α-synuclein-induced toxicity in vitro and in vivo. Our study may support oolong tea extracts as potential candidates for the prevention of neurodegenerative diseases.

Gallic Acid Prevents the Oxidative and Endoplasmic Reticulum Stresses in the Hippocampus of Adult-Onset Hypothyroid Rats

Thyroid hormone is essential for hippocampal redox environment and neuronal viability in adulthood, where its deficiency causes hypothyroidism related to oxidative and endoplasmic reticulum stresses in the hippocampus, resulting in neuronal death. One option of treatment is antioxidants; however, they must be transported across the blood-brain barrier. Gallic acid is a polyphenol that meets these criteria. Thus, this study aimed to prove that the neuroprotective mechanism of GA is associated with the prevention of oxidative and endoplasmic reticulum stresses in the hippocampus of adult-onset hypothyroid rats. Male Wistar rats were divided into euthyroid (n = 20) and hypothyroid groups (n = 20). Thyroidectomy with parathyroid gland reimplementation caused hypothyroidism. Each group was subdivided into two: vehicle and 50 mg/kg/d of gallic acid. 3 weeks after thyroidectomy, six animals of each group were euthanized, and the hippocampus was dissected to evaluate oxidative and endoplasmic reticulum stress markers. The rest of the animals were euthanized after 4 weeks of treatment for histological analysis of the hippocampus. The results showed that hypothyroidism increased lipid peroxidation, reactive oxygen species, and nitrites; it also increased endoplasmic reticulum stress by activating the inositol-requiring enzyme-1α (IRE1α) pathway, the protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activated transcription factor 6α (ATF6α) pathways associated with a proapoptotic state that culminates in hippocampal neuronal damage. Meanwhile, the hypothyroid rat treated with gallic acid reduced oxidative stress and increased endoplasmic reticulum-associated degradation (ERAD) through IRE1α and ATF6. Also, the gallic acid treatment prevented the Bax/BCl2 ratio from increasing and the overexpression of p53 and caspase 12. This treatment in hypothyroid animals was associated with the neuronal protection observed in the hippocampus. In conclusion, gallic acid prevents hypothyroidism-induced hippocampal damage associated with oxidative and endoplasmic reticulum stresses.

He-Ne Laser Seed Treatment Improves the Nutraceutical Metabolic Pool of Sunflowers and Provides Better Tolerance Against Water Deficit

Water-scarce areas are continually increasing worldwide. This factor reduces the quantity and quality of crops produced in affected areas. Physical seed treatments are considered economical and ecofriendly solutions for such problems. It was hypothesized that a moderately drought-tolerant crop grown from seeds treated with a He-Ne laser utilizes water-limited conditions better than plants grown from untreated seeds. A field study was conducted, growing a moderately drought tolerant crop (sunflower) with supportive seed treatment (He-Ne laser treatment at 300 mJ) for 0, 1, 2, and 3 min. Thirty-day-old plants were subjected to two irrigation conditions: 100% (normal) and 50% (water stress). Harvesting was done at flowering (60-day-old plants) at full maturity. The sunflowers maintained growth and yield under water limitation with a reduced achene number. At 50%, irrigation, there was a reduction in chlorophyll a, a+b and a/b; catalase activity; soluble sugars; and anthocyanin, alongside elevated proline. The improved chlorophyll a, a+b and a/b; metabolisable energy; nutritional value; and yield in the plants grown from He-Ne-laser-treated seeds support our hypothesis. Seeds with 2-min exposure to a He-Ne laser performed best regarding leaf area; leaf number; leaf biomass; chlorophyll a, a+b and a/b; per cent oil yield; 50-achene weight; achene weight per plant; carotenoid content; and total soluble phenolic compound content. Thereafter, the leaves from the best performing level of treatment (2 min) were subjected to high-performance-liquid-chromatography-based phenolic profiling and gas-chromatography-based fatty acid profiling of the oil yield. The He-Ne laser treatment led to the accumulation of nutraceutical phenolic compounds and improved the unsaturated-to-saturated fatty acid ratio of the oil. In conclusion, 2-min He-Ne laser seed treatment could be the best strategy to improve the yield and nutritional value of sunflowers grown in water-limited areas.

Anacardium Occidentale L. Leaf Extracts Protect Against Glutamate/H2O2-Induced Oxidative Toxicity and Induce Neurite Outgrowth: The Involvement of SIRT1/Nrf2 Signaling Pathway and Teneurin 4 Transmembrane Protein

Neurodegenerative diseases are linked to neuronal cell death and neurite outgrowth impairment that are often caused by oxidative stress. Natural products, which have neuroprotective against oxidative stress and neurite outgrowth inducing activity, could be potential candidates for alternative treatment of neurodegenerative diseases. This study aims to investigate the neuroprotective effects and neuritogenesis properties of Anacardium occidentale leaf extracts in cultured neuronal (HT22 and Neuro-2a) cells. We found gallic acid, catechin and quercetin as the main compounds in A. occidentale extracts. The extracts have a protective effect against glutamate/H₂O₂-mediated oxidative stress-induced cell toxicity. The gene expression of cellular antioxidant enzymes (SODs, GPx and, GSTs) were up-regulated by this treatment. The treatment also triggered SIRT, Nrf2 proteins as well as the mRNA transcriptions of relevant anti-oxidation genes (NQO1, GCLM, and EAAT3). We demonstrated that the extracts promote antioxidant defense in neuronal cells via the SIRT1/Nrf2 signaling pathway. Moreover, the extracts increase neurite outgrowth and Ten-4 expression in Neuro-2a cells. However, the neuritogenesis properties did not occur, when Ten-4 expression was knocked down by corresponding siRNA. These results suggest that the leaf extracts have an interesting neuritogenesis and neuroprotective potential against glutamate/H₂O₂-mediated toxicity and could be a potential therapeutic candidate for neurodegenerative diseases.

Flavonoids from edible fruits as therapeutic agents in neuroinflammation - a comprehensive review and update

Neuroinflammation is a key process in the pathogenesis of many neurological disorders, i.e. Alzheimer's disease and Parkinson's disease. However, there are no anti-inflammatory medical interventions recommended so far in the treatment of neuroinflammation-related brain disorders. Therefore, the burden of searching for effective and safe antineuroinflammatory agents is well founded, especially in the aging society. Compounds of plant origin, mainly (poly)phenols, have attracted considerable attention in recent years. Notably, the role of flavonoids in ameliorating neuroinflammation is in the limelight. Thus, we used comprehensive literature retrieval to summarize the effects and active components of edible fruits and their phenolic compounds. As a result, this review presents a valuable summary of results of in vitro, ex vivo, and in vivo studies on the antineuroinflammatory effects of edible fruits and their (poly)phenolic extracts as well as dietary flavonoids and other selected (poly)phenols based on the detailed description of foregoing studies. Additionally, problems resulting from the limited bioavailability of (poly)phenols were discussed.

A comprehensive review on phytochemistry, bioactivities, toxicity studies, and clinical studies on Ficus carica Linn. leaves

The leaves of Ficus carica Linn. (FC) have been widely used for medicine purposes since ancient times, and its decoction is consumed as tea. Many scientific papers have been published in the literature and the researchers across the world are still exploring the health benefits of FC leaves. In this review, we have collected the literature published since 2010 in the databases: Pubmed, Scopus, Web of Science, SciFinder, Google Scholar, Baidu Scholar and local classic herbal literature. The summary of the chemical constituents in FC leaves, biological activities, toxicity studies, and clinical studies carried out on FC leaves is provided in this review. In addition, the molecular mechanisms of the active constituents in FC leaves are also comprehended. FC leaves are reported to 126 constituents out of which the polyphenolic compounds are predominant. Many scientific studies have proven the antidiabetic, antioxidant, anti-inflammatory, anticancer, anticholinesterase, antimicrobial, hepatoprotective, and renoprotective activities. Many studies have carried out to provide the insights on molecular pathways involved in the biological activities of FC leaves. The toxicity studies have suggested that FC leaves exhibit toxicity only at very high doses. We believe this review serve as a comprehensive resource for those who are interested to understand the scientific evidence that support the medicinal values of FC leaves and also the research gaps to further improve the commercial value and health benefits of FC leaves.

NaoXinTong Capsule ameliorates memory deficit in APP/PS1 mice by regulating inflammatory cytokines

Alzheimer's disease (AD) is the most common neurodegenerative disease in aging population. Neuroinflammation, hyperphosphorylated Tau (p-Tau) and the imbalance between production and clearance of β-amyloid peptide (Aβ) are the major causes for AD development. NaoXinTong Capsule (NXT), a traditional Chinese medicine, is wildly used for treatment of cardiovascular and cerebrovascular diseases. Hence, we used the double transgenic mice expressing chimeric human amyloid precursor protein and mutant human presenilin 1 (APP/PS1) and HT-22 cells to determine the neuroprotective effects of NXT in AD development and the involved mechanisms. The 3-month-old APP/PS1 mice were randomly divided into 3 groups and received following treatment: Control group, mice were fed normal chow; NXT groups, mice were fed normal chow containing NXT at a normal and a high dose, respectively. While the age-matched C57BL/6J mice fed normal chow were used as the normal control. The NXT treatment was lasted for 5 months. We found that NXT treatment improved spatial memory impairment and cognitive decline in APP/PS1 mice by decreasing p-Tau levels and Aβ accumulation in the brain. Mechanistically, we observed that NXT inhibited neuron atrophy and apoptosis by downregulating inflammatory cytokines, interleukin 1β (IL-1β), IL-6 and tumor necrosis factor α (TNF-α), and inflammation mediators, nuclear factor κB (NF-κB) and toll-like receptor 4 (TLR4) in the brain. Consistently, NXT blocked l-glutamic acid-induced reactive oxygen species production, inflammation and apoptosis in HT-22 cells partially by inhibiting TLR4/NF-κB/IL-1β signaling pathway. Our study demonstrates that NXT ameliorates AD by reducing p-Tau, Aβ accumulation, inflammation and neuron apoptosis via regulation of TLR4-mediated inflammatory system. It also suggests the potential application of NXT for AD treatment.

Gallic Acid Reverses Neurochemical Changes Induced by Prolonged Ethanol Exposure in the Zebrafish Brain

Gallic acid (GA) is a polyphenolic compound that has attracted significant interest due to its antioxidant action through free radical elimination and metal chelation. Ethanol is a highly soluble psychoactive substance, and its toxicity is associated with oxidative stress. In this context, the purpose of the present study was to investigate the effect of GA on neurochemical changes in zebrafish brains exposed to ethanol. GA was first analyzed in isolation by treating the animals at concentrations of 5, 10, and 20 mg/L for 24 h and 48 h. The results revealed that the group exposed to 20 mg/L over a 24/48 h period exhibited increases in thiobarbituric acid reactive substance (TBA-RS) levels and 2',7'-dichlorofluorescein (DCFH) oxidation, demonstrating a pro-oxidant profile. Moreover, decrease in acetylcholinesterase (AChE) enzyme activity was observed. To investigate the effects of GA after ethanol exposure, the animals were divided into four groups: control; those exposed to 0.5% ethanol for 7 days; those exposed to 0.5% ethanol for 7 days and treated with GA at 5 and 10 mg/L on day 8. Treatment with GA at 5 and 10 mg/L reversed impairment of choline acetyltransferase activity and the damage to TBA-RS levels, DCFH oxidation, and superoxide dismutase activity induced by ethanol. Results of the present study suggest that GA treatment (20 mg/L) appeared to disrupt oxidative parameters in the zebrafish brain. GA treatment at 5 and 10 mg/L reversed alterations to the cholinergic system induced by prolonged exposure to ethanol in the zebrafish brain, probably through an antioxidant mechanism.

The Anti-Neuroinflammatory Role of Anthocyanins and Their Metabolites for the Prevention and Treatment of Brain Disorders

Anthocyanins are naturally occurring polyphenols commonly found in fruits and vegetables. Numerous studies have described that anthocyanin-rich foods may play a crucial role in the prevention and treatment of different pathological conditions, which have encouraged their consumption around the world. Anthocyanins exhibit a significant neuroprotective role, mainly due to their well-recognized antioxidant and anti-inflammatory properties. Neuroinflammation is an intricate process relevant in both homeostatic and pathological circumstances. Since the progression of several neurological disorders relies on neuroinflammatory process, targeting brain inflammation has been considered a promising strategy in those conditions. Recent data have shown the anti-neuroinflammatory abilities of many anthocyanins and of their metabolites in the onset and development of several neurological disorders. In this review, it will be discussed the importance and the applicability of these polyphenolic compounds as neuroprotective agents and it will be also scrutinized the molecular mechanisms underlying the modulation of neuroinflammation by these natural compounds in the context of several brain diseases.

Molecular evaluation of quorum quenching potential of vanillic acid against Yersinia enterocolitica through transcriptomic and in silico analysis

Introduction. Yersinia enterocolitica is one of the leading food-borne entero-pathogens causing various illnesses ranging from gastroenteritis to systemic infections. Quorum sensing (QS) is one of the prime mechanisms that control the virulence in Y. enterocolitica .

Hypothesis/Gap Statement. Vanillic acid inhibits the quorum sensing and other virulence factors related to Y. enterocolitica . It has been evaluated by transcriptomic and Insilico analysis. Therefore, it can be a prospective agent to develop a therapeutic combination against Y. enterocolitica .

Aim. The present study is focused on screening natural anti-quorum-sensing agents against Y. enterocolitica . The effect of selected active principle on various virulence factors was evaluated.

Methodology. In total, 12 phytochemicals were screened by swarming assay. MATH assay, EPS and surfactant production assay, SEM analysis, antibiotic and blood sensitivity assay were performed to demonstrate the anti-virulence activity. Further, RNA sequencing and molecular docking studies were carried out to substantiate the anti-QS activity.

Results. Vanillic acid (VA) has exhibited significant motility inhibition, thus indicating the anti-QS activity with MQIC of 400 µg ml−1 without altering the cell viability. It has also inhibited the violacein production in Chromobacterium violaceum ATCC 12472, which further confirms the anti-QS activity. VA has inhibited 16 % of cell-surface hydrophobicity (CSH), 52 % of EPS production and 60 % of surfactant production. Moreover, it has increased the sensitivity of Y. enterocolitica towards antibiotics. It has also made the cells upto 91 % more vulnerable towards human immune cells. The transcriptomic analysis by RNA sequencing revealed the down regulation of genes related to motility, virulence, chemotaxis, siderophores and drug resistance. VA treatment has also positively regulated the expression of several stress response genes. In furtherance, the anti-QS potential of VA has been validated with QS regulatory protein YenR by in silico molecular simulation and docking study.

Conclusion. The present study is possibly the first attempt to demonstrate the anti-QS and anti-pathogenic potential of VA against Y. enterocolitica by transcriptomic and in silico analysis. It also deciphers that VA can be a promising lead to develop biopreservative and therapeutic regimens to treat Y. enterocolitica infections.

Characterization of metabolite profiles of white and green spears of asparagus officinalis L. from Caoxian, East China

China is the largest planting country of asparagus (Asparagus officinalis L.) in the world. Caoxian, as the famous asparagus township in China, enjoys a reputation for producing asparagus with high yield and good quality, due to its unique geological characteristic. In this study, a method of reverse-phase ultraperformance liquid chromatography coupled with electrospray tandem mass spectrometry (RP-UPLC-ESI-MS/MS) was established for profiling metabolites from three segments (tip, mid, and base) of 'Caoxian white and green Asparagus'. A total of 114 metabolites were identified, among them, 43 were found for the first time in this vegetable. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) was applied to provide an overview of the metabolite profiles of Caoxian asparagus and to separate different segments of spears. The variables most decisive to discriminate among segments included 9 of the metabolites tentatively identified. This study will help to improve the protection of Caoxian asparagus geographical indication.

Madecassic Acid Reduces Fast Transient Potassium Channels and Promotes Neurite Elongation in Hippocampal CA1 Neurons

BACKGROUND AND OBJECTIVE

Madecassic Acid (MA) is well known to induce neurite elongation. However, its correlation with the expression of fast transient potassium (AKv) channels during neuronal development has not been well studied. Therefore, the present study was designed to investigate the effects of MA on the modulation of AKv channels during neurite outgrowth.

METHODS

Neurite outgrowth was measured with morphometry software, and Kv4 currents were recorded by using the patch clamp technique.

RESULTS

The ability of MA to promote neurite outgrowth is dose-dependent and was blocked by using the mitogen/extracellular signal-regulated kinase (MEK) inhibitor U0126. MA reduced the peak current density and surface expression of the AKv channel Kv4.2 with or without the presence of NaN3. The surface expression of Kv4.2 channels was also reduced after MA treatment of growing neurons. Ethylene glycol tetraacetic acid (EGTA) and an N-methyl-D-aspartate (NMDA) receptor blocker, MK801 along with MA prevented the effect of MA on neurite length, indicating that calcium entry through NMDA receptors is necessary for MA-induced neurite outgrowth.

CONCLUSION

The data demonstrated that MA increased neurite outgrowth by internalizing AKv channels in neurons. Any alterations in the precise density of ion channels can lead to deleterious consequences on health because it changes the electrical and mechanical function of a neuron or a cell. Modulating ion channel's density is exciting research in order to develop novel drugs for the therapeutic treatment of various diseases of CNS.

Microbial Metabolites of Flavan-3-Ols and Their Biological Activity

Flavan-3-ols are the main contributors to polyphenol intake. Many varying beneficial health effects in humans have been attributed to them, including the prevention of cardiovascular disease and cancer. Nevertheless, the mechanisms by which these flavonoids could exert beneficial functions are not entirely known. Several in vitro studies and in vivo animal models have tried to elucidate the role of the specific colonic metabolites on the health properties that are attributed to the parent compounds since a larger number of ingested flavan-3-ols reach the colon and undergo there microbial metabolism. Many new studies about this topic have been performed over the last few years and, to the best of our knowledge, no scientific literature review regarding the bioactivity of all identified microbial metabolites of flavan-3-ols has been recently published. Therefore, the aim of this review is to present the current status of knowledge on the potential health benefits of flavan-3-ol microbial metabolites in humans while using the latest evidence on their biological activity.

Anthocyanins and Their Metabolites as Therapeutic Agents for Neurodegenerative Disease

Neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis (ALS), are characterized by the death of neurons within specific regions of the brain or spinal cord. While the etiology of many neurodegenerative diseases remains elusive, several factors are thought to contribute to the neurodegenerative process, such as oxidative and nitrosative stress, excitotoxicity, endoplasmic reticulum stress, protein aggregation, and neuroinflammation. These processes culminate in the death of vulnerable neuronal populations, which manifests symptomatically as cognitive and/or motor impairments. Until recently, most treatments for these disorders have targeted single aspects of disease pathology; however, this strategy has proved largely ineffective, and focus has now turned towards therapeutics which target multiple aspects underlying neurodegeneration. Anthocyanins are unique flavonoid compounds that have been shown to modulate several of the factors contributing to neuronal death, and interest in their use as therapeutics for neurodegeneration has grown in recent years. Additionally, due to observations that the bioavailability of anthocyanins is low relative to that of their metabolites, it has been proposed that anthocyanin metabolites may play a significant part in mediating the beneficial effects of an anthocyanin-rich diet. Thus, in this review, we will explore the evidence evaluating the neuroprotective and therapeutic potential of anthocyanins and their common metabolites for treating neurodegenerative diseases.