Neuroprotective Effects of Phenolic and Carboxylic Acids on Oxidative Stress-Induced Toxicity in Human Neuroblastoma SH-SY5Y Cells

Deciphering neuroprotective mechanism of nitroxoline in cerebral ischemia: network pharmacology and molecular modeling-based investigations

Cerebral ischemia is one of the major causes of death and disability worldwide. Currently, existing approved therapies are based on reperfusion and there is an unmet need to search for drugs with neuroprotective effects. The present study aims to investigate the neuroprotective mechanisms of nitroxoline, a nitro derivative of 8-Hydroxyquinoline, against cerebral ischemia using integrated network pharmacology and molecular docking approaches. Critical analytical tools used were SwissTarget, PharmMapper, BindingDB, DisGeNet, Cytoscape, GeneMANIA, ShinyGo, Metascape, GeneCodis, and Schrodinger GLIDE. Thirty-six overlapping drug and disease targets were identified and used for further analysis. Gene Ontology results showed that nitroxoline enriched the genes involved in biological processes of oxidative stress and apoptotic cell death that are highly implicated in hypoxic injury. KEGG enrichment analysis showed nitroxoline influenced a total of 159 biological pathways, out of which, top pathways involved in cerebral ischemia included longevity regulating pathway, VEGF signaling, EGFR tyrosine kinase inhibitor resistance, IL-17 and HIF-1 pathways, FoxO signaling, and AGE-RAGE pathway. Protein-protein interaction analysis using string database showed PARP1, EGFR, PTEN, BRD4, RAC1, NOS2, MTOR, MAPK3, BCL2, MAPK1, APP, METAP2, MAPK14, SIRT1, PRKAA1, and MCL1 as highly interactive proteins involved in pathogenesis of ischemic stroke regulated by nitroxoline. The highly interactive protein targets were validated by molecular docking studies and molecular dynamic simulations. Amongst all these targets, nitroxoline showed the highest binding affinity towards BRD4 followed by PARP1 and PTEN. Nitroxoline, through network pharmacology analysis, showed a role in regulating proteins, biological processes, and pathways crucial in cerebral ischemia. The current study thus provides a preliminary insight that nitroxoline might be used as a neuroprotectant against cerebral ischemia via modulating the epigenetic reader BRD4 and transcription factors such as RELA, NF-κβ1, and SP1. However, further in-vitro and preclinical studies need to be performed for concrete evidence.

Advances in identifying and managing emerging contaminants in aquatic ecosystems: Analytical approaches, toxicity assessment, transformation pathways, environmental fate, and remediation strategies

Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management.

Promising 8-Aminoquinoline-Based Metal Complexes in the Modulation of SIRT1/3-FOXO3a Axis against Oxidative Damage-Induced Preclinical Neurons

The discovery of novel bioactive molecules as potential multifunctional neuroprotective agents has clinically drawn continual interest due to devastating oxidative damage in the pathogenesis and progression of neurodegenerative diseases. Synthetic 8-aminoquinoline antimalarial drug is an attractive pharmacophore in drug development and chemical modification owing to its wide range of biological activities, yet the underlying molecular mechanisms are not fully elucidated in preclinical models for oxidative damage. Herein, the neuroprotective effects of two 8-aminoquinoline-uracil copper complexes were investigated on the hydrogen peroxide-induced human neuroblastoma SH-SY5Y cells. Both metal complexes markedly restored cell survival, alleviated apoptotic cascades, maintained antioxidant defense, and prevented mitochondrial function by upregulating the sirtuin 1 (SIRT1)/3-FOXO3a signaling pathway. Intriguingly, in silico molecular docking and pharmacokinetic prediction suggested that these synthetic compounds acted as SIRT1 activators with potential drug-like properties, wherein the uracil ligands (5-iodoracil and 5-nitrouracil) were essential for effective binding interactions with the target protein SIRT1. Taken together, the synthetic 8-aminoquinoline-based metal complexes are promising brain-targeting drugs for attenuating neurodegenerative diseases.

Neuroprotective Agents with Therapeutic Potential for COVID-19

COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.

Aminochalcones Attenuate Neuronal Cell Death under Oxidative Damage via Sirtuin 1 Activity

Encouraged by the lack of effective treatments and the dramatic growth in the global prevalence of neurodegenerative diseases along with various pharmacological properties of chalcone pharmacophores, this study focused on the development of aminochalcone-based compounds, organic molecules characterized by a chalcone backbone (consisting of two aromatic rings connected by a three-carbon α,β-unsaturated carbonyl system) with an amino group attached to one of the aromatic rings, as potential neuroprotective agents. Thus, the aminochalcone-based compounds in this study were designed by bearing a -OCH3 moiety at different positions on the ring and synthesized by the Claisen-Schmidt condensation. The compounds exhibited strong neuroprotective effects against hydrogen peroxide-induced neuronal death in the human neuroblastoma (SH-SY5Y) cell line (i.e., by improving cell survival, reducing reactive oxygen species production, maintaining mitochondrial function, and preventing cell membrane damage). The aminochalcone-based compounds showed mild toxicity toward a normal embryonic lung cell line (MRC-5) and a human neuroblastoma cell line, and were predicted to have preferable pharmacokinetic profiles with potential for oral administration. Molecular docking simulation indicated that the studied aminochalcones may act as competitive activators of the well-known protective protein, SIRT1, and provided beneficial knowledge regarding the essential key chemical moieties and interacting amino acid residues. Collectively, this work provides a series of four promising candidate agents that could be developed for neuroprotection.

Possible Signaling Pathways in the Gut Microbiota-Brain Axis for the Development of Parkinson's Disease Caused by Chronic Consumption of Food Additives

It is well-known that consumption of synthetic and natural food additives has both positive and negative effects in the human body. However, it is not clear yet how food additives are related to the development of Parkinson's disease. Therefore, in this review work, the food additive effects related to the gut microbiota-brain axis and the processes that are carried out to develop Parkinson's disease are studied. To this end, a systematic literature analysis is performed with the selected keywords and the food additive effects are studied to draw possible routes of action. This analysis leads to the proposition of a model that explains the pathways that relate the ingestion of food additives to the development of Parkinson's disease. This work motivates further research that ponders the safety of food additives by measuring their impacts over the gut microbiota-brain axis.

Practical and Rapid Membrane-Based Biosensor for Phenol Using Copper/Calcium-Enzyme Hybrid Nanoflowers

Phenol, a pollutant frequently found in chemical industries effluents, is highly toxic even in low concentrations. This study reports a green, simple, and rapid method for qualitative phenol biosensing using horseradish peroxidase (HRP) hybrid nanoflowers made with copper (Cu²⁺-hNF) or calcium (Ca²⁺-hNF) ions. The enzyme was immobilized through protein-inorganic self-assembly into hybrid structures and subsequently supported onto a polyvinylidene fluoride (PVDF) membrane. SEM, EDS, FTIR, and XRD techniques sustained the effective enzyme encapsulation into hybrid structures. The protein concentration in the structures was 0.25 mg.mL^-1 for both ions. The best temperature and pH were 60 °C and 7.4, respectively, for both hybrids and the free enzyme, suggesting that the immobilization did not affect the optimal conditions of the free HRP. Thermal stability from 25 to 70 °C and pH stability from 4.0 to 9.0 of the hybrids were also determined. Finally, using copper and calcium hybrids, both biosensors produced onto a PVDF membrane could detect phenol in concentrations ranging from 0.72 to 24.00 µmol.mL^-1 in 1 min. In contrast, control biosensors produced with free enzyme have not presented a visible color change in the same conditions. The findings suggest a promising application of the developed biosensors in functional phenol detection.

The effects of bioactive components from the rhizome of gastrodia elata blume (Tianma) on the characteristics of Parkinson's disease

Parkinson's disease (PD) is an age-related chronic neurodegenerative disease caused by the death and degeneration of dopaminergic neurons in the substantia nigra of the midbrain. The decrease of the neurotransmitter dopamine in the patient's brain leads to various motor symptoms. PD drugs mainly enhance dopamine levels but cannot prevent or slow down the loss of dopaminergic neurons. In addition, they exhibit significant side effects and addiction issues during long-term use. Therefore, it is particularly urgent to develop novel drugs that have fewer side effects, can improve PD symptoms, and prevent the death of dopaminergic neurons. The rhizome of Gastrodia elata Blume (Tianma) is a well-known medicinal herb and has long been used as a treatment of nervous system-related diseases in China. Several clinical studies showed that formula comprising Tianma could be used as an add-on therapy for PD patients. Pharmacological studies indicated that Tianma and its bioactive components can reduce the death of dopaminergic neurons, α-synuclein accumulation, and neuroinflammation in various PD models. In this review, we briefly summarize studies regarding the effects of Tianma and its bioactive components' effects on major PD features and explore the potential use of Tianma components for the treatment of PD.

Neuroprotective Properties of Bis-Sulfonamide Derivatives Against 6-OHDA-Induced Parkinson's Model via Sirtuin 1 Activity and in silico Pharmacokinetic Properties

Parkinson's disease (PD) is considered one of the health problems in the aging society. Due to the limitations of currently available drugs in preventing disease progression, the discovery of novel neuroprotective agents has been challenged. Sulfonamide and its derivatives were reported for several biological activities. Herein, a series of 17 bis-sulfonamide derivatives were initially tested for their neuroprotective potential and cytotoxicity against the 6-hydroxydopamine (6-OHDA)-induced neuronal death in SH-SY5Y cells. Subsequently, six compounds (i.e., 2, 4, 11, 14, 15, and 17) were selected for investigations on underlying mechanisms. The data demonstrated that the pretreatment of selected compounds (5 μM) can significantly restore the level of cell viability, protect against mitochondrial membrane dysfunction, decrease the activity of lactate dehydrogenase (LDH), decrease the intracellular oxidative stress, and enhance the activity of NAD-dependent deacetylase sirtuin-1 (SIRT1). Molecular docking was also performed to support that these compounds could act as SIRT1 activators. In addition, in silico pharmacokinetic and toxicity profile prediction was also conducted for guiding the potential development. Thus, the six neuroprotective bis-sulfonamides were highlighted as potential agents to be further developed for PD management.

A Comprehensive Review of C. capsularis and C. olitorious: A Source of Nutrition, Essential Phytoconstituents and Pharmacological Activities

Plant bioactive compounds have gained global significance in terms of both medicinal and economic ramifications due to being easily accessible and are believed to be effective with fewer side effects. Growing relevant clinical and scientific evidence has become an important criterion for accepting traditional health claims of medicinal plants and also supports the traditional uses of Corchorus as folk medicine. C. capsularis and C. olitorius have broad applications ranging from textile to biocomposite, and young leaves and shoots are used as healthy vegetables and have long been used as traditional remedies for fever, ascites, algesia, liver disorders, piles, and tumors in many cultures. This review systematically summarized and emphasized the nutritional attributes, mostly available bioactive compounds, and biological and potential pharmaceutical properties of C. capsularis and C. olitorius, disclosed to users and non-users. Results suggest that various phytochemicals such as cardiac glycosides, phenols, flavonoids, sterols, lipids, and fatty acids were found or analytically identified in different plant parts (leaf, stem, seed, and root), and many of them are responsible for pharmacological properties and their antitumor, anticancer, antioxidant, antinociceptive, anti-inflammatory, analgesic, antipyretic, antiviral, antibacterial, anticonvulsant, antidiabetic and antiobesity, and cardiovascular properties help to prevent and cure many chronic diseases. In addition to their use in traditional food and medicine, their leaves have also been developed for skin care products, and some other possible uses are described. From this review, it is clear that the isolated compounds of both species have great potential to prevent and treat various diseases and be used as functional foods. In conclusion, this comprehensive review establishes a significant reference base for future research into various medical and functional food applications.

Blood–Brain Barrier Permeability Study of Potential Neuroprotective Compounds Recovered From Plants and Agri-Food by-Products

Plants and agri-food by-products represent a wide and renewable source of bioactive compounds with neuroprotective properties. In this research, various green extraction techniques were employed to recover bioactive molecules from Kalanchoe daigremontiana (kalanchoe), epicarp of Cyphomandra betacea (tamarillo), and cooperage woods from Robinia pseudoacacia (acacia) and Nothofagus pumilio (lenga), as well as a reference extract (positive control) from Rosmarinus officinalis L. (rosemary). The neuroprotective capacity of these plant extracts was evaluated in a set of in vitro assays, including enzymatic [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and lipoxygenase (LOX)] and antioxidant [ABTS, and reactive oxygen and nitrogen species (ROS and RNS)] bioactivity tests. Extracts were also submitted to a parallel artificial membrane permeability assay mimicking the blood–brain barrier (PAMPA-BBB) and to two cell viability assays in HK-2 and SH-SY5Y cell lines. Comprehensive phytochemical profiling based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) analysis showed enriched content of phenolic and terpenoid compounds in the target extracts. Moreover, in vitro bioactivity tests showed promising neuroprotective capacity, particularly for supercritical-fluid extraction (SFE) extract from acacia (ABTS IC₅₀ = 0.11 μg ml⁻¹; ROS IC₅₀ = 1.56 μg ml⁻¹; AChE IC₅₀ = 4.23 μg ml⁻¹; BChE IC₅₀ = 1.20 μg ml⁻¹; and LOX IC₅₀ = 4.37 μg ml⁻¹), whereas PAMPA-BBB assays revealed high perfusion capacity of some representative compounds, such as phenolic acids or flavonoids. Regarding cytotoxic assays, tamarillo and rosemary SFE extracts can be considered as non-toxic, acacia SFE extract and lenga pressurized liquid extraction (PLE) extract as mild-cytotoxic, and kalanchoe as highly toxic extracts. The obtained results demonstrate the great potential of the studied biomass extracts to be transformed into valuable food additives, food supplements, or nutraceuticals with promising neuroprotective properties.

Silibinin Protects against H2O2-Induced Oxidative Damage in SH-SY5Y Cells by Improving Mitochondrial Function

Oxidative stress plays a critical role in the pathogenesis of various neurodegenerative diseases. Increasing evidence suggests the association of mitochondrial abnormalities with oxidative stress-related neural damage. Silibinin, a natural flavonol compound isolated from Silybum marianum, exhibits multiple biological activities. The present study investigated the effects of silibinin on H₂O₂-induced oxidative stress in human neuroblastoma SH-SY5Y cells. Exposure to H₂O₂ (750 µM) reduced the viability of SH-SY5Y cells, which was coupled with increased reactive oxygen species (ROS), abnormal cell morphology, and mitochondrial dysfunction. Remarkably, silibinin (1, 5, and 10 µM) treatment attenuated the H₂O₂-induced cell death. Moreover, silibinin reduced ROS production and the levels of malondialdehyde (MDA), increased the levels of superoxide dismutase (SOD) and glutathione (GSH), and increased mitochondrial membrane potential. Moreover, silibinin normalized the expression of nuclear factor 2-related factor 2 (Nrf2)-related and mitochondria-associated proteins. Taken together, our findings demonstrated that silibinin could attenuate H₂O₂-induced oxidative stress by regulating Nrf2 signaling and improving mitochondrial function in SH-SY5Y cells. The protective effect against oxidative stress suggests silibinin as a potential candidate for preventing neurodegeneration.

Design and Synthesis of Arylpiperazine Serotonergic/Dopaminergic Ligands with Neuroprotective Properties

Long-chain arylpiperazine scaffold is a versatile template to design central nervous system (CNS) drugs that target serotonin and dopamine receptors. Here we describe the synthesis and biological evaluation of ten new arylpiperazine derivatives designed to obtain an affinity profile at serotonin 5-HT_1A, 5-HT_2A, 5-HT₇ receptor, and dopamine D₂ receptor of prospective drugs to treat the core symptoms of autism spectrum disorder (ASD) or psychosis. Besides the structural features required for affinity at the target receptors, the new compounds incorporated structural fragments with antioxidant properties to counteract oxidative stress connected with ASD and psychosis. All the new compounds showed CNS MultiParameter Optimization score predictive of desirable ADMET properties and cross the blood–brain barrier. We identified compound 12a that combines an affinity profile compatible with antipsychotic activity (5-HT_1AK_i = 41.5 nM, 5-HT_2AK_i = 315 nM, 5-HT₇K_i = 42.5 nM, D₂K_i = 300 nM), and compound 9b that has an affinity profile consistent with studies in the context of ASD (5-HT_1AK_i = 23.9 nM, 5-HT_2AK_i = 39.4 nM, 5-HT₇K_i = 45.0 nM). Both compounds also had antioxidant properties. All compounds showed low in vitro metabolic stability, the only exception being compound 9b, which might be suitable for studies in vivo.

Interaction Between Diet and Microbiota in the Pathophysiology of Alzheimer's Disease: Focus on Polyphenols and Dietary Fibers

Animal studies increasingly indicate that the gut microbiota composition and function can be involved in the pathophysiology and progression of Alzheimer's disease (AD) at multiple levels. However, few studies have investigated this putative gut-brain axis in human beings, and none of them considered diet as a determinant of intestinal microbiota composition. Epidemiological studies highlight that a high intake of fruit and vegetables, such as that typical of the Mediterranean diet, can modulate AD progression. Thus, nutritional interventions are being increasingly studied as a possible non-pharmacological strategy to slow down the progression of AD. In particular, polyphenols and fibers represent the nutritional compounds with the higher potential of counterbalancing the pathophysiological mechanisms of dementia due to their antioxidant, anti-inflammatory, and anti-apoptotic properties. These actions are mediated by the gut microbiota, that can transform polyphenols and fibers into biologically active compounds including, among others, phenyl-γ-valerolactones, urolithins, butyrate, and other short-chain fatty acids. In this review, the complex mechanisms linking nutrition, gut microbiota composition, and pathophysiology of cognitive decline in AD are discussed, with a particular focus on the role of polyphenols and fibers. The gaps between pre-clinical and clinical studies are particularly emphasized, as well as the urgent need for studies comprehensively evaluating the link between nutrition, microbiome, and clinical aspects of AD.

Modulatory Effects of Alpha-Mangostin Mediated by SIRT1/3-FOXO3a Pathway in Oxidative Stress-Induced Neuronal Cells

Background

alpha-Mangostin, a polyphenolic xanthone, is primarily found in the pericarp of mangosteen throughout Southeast Asia and is considered as the “Queen of Fruit” in Thailand. Nonetheless, it is not clarified how alpha-mangostin protects neuronal cells against oxidative stress.

Objective

In this study, molecular mechanisms underlying the neuroprotective effect of alpha-mangostin in defending hydrogen peroxide (H2O2)-induced neurotoxicity was explored.

Methods

cytotoxicity, reactive oxygen species (ROS) generation, apoptotic cascades, and protein expression profiles were performed incorporation of molecular docking.

Results

Human SH-SY5Y cells were pretreated with 1 μM alpha-mangostin for 3 h prior to exposure to 400 μM H2O2. alpha-Mangostin significantly inhibited oxidative stress-induced cell death in neuronal cells by reducing BAX protein, decreasing caspase-3/7 activation, and increasing anti-apoptotic BCL-2 protein. Collectively, alpha-mangostin was demonstrated to be a prominent ROS suppressor which reversed the reduction of antioxidant enzymes (CAT and SOD2). Surprisingly, alpha-mangostin significantly promoted the expression of the sirtuin family and the FOXO3a transcription factor exerting beneficial effects on cell survival and longevity. A molecular docking study predicted that alpha-mangostin is directly bound to the active site of SIRT1.

Conclusion

Findings from this study suggest that alpha-mangostin potentially serves as a promising therapeutic compound against oxidative stress by activation of the SIRT1/3-FOXO3a pathway comparable to the effect of memantine, an anti-AD drug used for the treatment of moderate to severe dementia.

Additive cell protective and oxidative stress reducing effects of combined treatment with cromolyn sodium and masitinib on MPTP-induced toxicity in SH-SY5Y neuroblastoma cells

The suppression of oxidative-stress induced neurotoxicity by antioxidants serves as a potential preventive strategy for neurodegenerative diseases. In this study, we aimed to investigate the cell protective and antioxidant effects of masitinib and cromolyn sodium against toxin-induced neurodegeneration. First, human neuroblastoma SH-SY5Y cells were differentiated into neuron-like (d)-SH-SY5Y cells. The differentiated cells were confirmed by immuno-staining with anti-PGP9.5 antibody, a neuronal marker. Cell culture groups were formed, and a neurotoxin, 1-methyl-4-phenyl1,2,3,6-tetrahydropyridine (MPTP) was applied on cells followed by masitinib and/or cromolyn sodium treatments. Survival rates of cells were detected by MTT assay. Anti-inflammatory Transforming Growth Factor-β1 (TGF-β1) and nitric oxide (NO) levels and total oxidant and antioxidant capacities (TOC and TAC) in cell conditioned media (CM) were measured. Morphological analysis and apoptotic nuclear assessment of cells were also noted. When (d)-SH-SY5Y cells were exposed to neurotoxin, cell viability rates of these cells were found to be decreased in a dose-dependent manner. CM of toxin applied groups displayed higher levels of TOC/TAC ratios and NO levels compared to control (p < 0.01). Both masitinib and cromolyn protected cells from toxin-induced cell death as revealed by ameliorated rates of viability and reversed toxin-induced elevation of TOC/TAC ratios and decreased NO levels in their CM. Combined treatment significantly reduced TOC/TAC ratios and NO levels more effectively compared to mono-treatments. Both drugs also increased TGF-β1 levels in cell CM. When these agents were tested for therapeutic effects against toxin-induced cell degeneration, better viability results were obtained by both masitinib and cromolyn sodium treatment, with significantly better amelioration provided by combined application of these drugs (p < 0.01). This study demonstrated new findings that combined treatment with cromolyn an FDA-approved drug of asthma, and masitinib, an orally administered drug with a low toxicity, exert neuroprotective and additive therapeutic effects. We propose combination therapy of masitinib and cromolyn may represent an innovative treatment in neurodegenerative diseases. Combination therapy may be more advantageous that it enables combined application of lower doses of both drugs, providing less side effects.

Anti-Inflammatory and Antiproliferative Properties of Sweet Cherry Phenolic-Rich Extracts

Cherries have largely been investigated due to their high content in phenolics in order to fully explore their health-promoting properties. Therefore, this work aimed to assess, for the first time, the anti-inflammatory potential of phenolic-targeted fractions of the Saco cherry, using RAW 264.7 macrophages stimulated with lipopolysaccharide. Additionally, the cytotoxic effects on gastric adenocarcinoma (AGS), neuroblastoma (SH-SY5Y) and normal human dermal fibroblast (NHDF) cells were evaluated, as well as the ability to protect these cellular models against induced oxidative stress. The obtained data revealed that cherry fractions can interfere with cellular nitric oxide (NO) levels by capturing NO radicals and decreasing inducible nitric oxide synthase and cyclooxygenase-2 expression. Furthermore, it was observed that all cherry fractions exhibited dose-dependent cytotoxicity against AGS cells, presenting cytotoxic selectivity for these cancer cells when compared to SH-SY5Y and NHDF cells. Regarding their capacity to protect cancer cells against oxidative injury, in most assays, the total cherry extract was the most effective. Overall, this study reinforces the idea that sweet cherries can be incorporated into new pharmaceutical products, smart foods and nutraceuticals.

Antioxidant Effects of Protocatechuic Acid and Protocatechuic Aldehyde: Old Wine in a New Bottle

Phenolic compounds are naturally present as secondary metabolites in plant-based sources such as fruits, vegetables, and spices. They have received considerable attention for their antioxidant, anti-inflammatory, and anti-carcinogenic properties for protection against many chronic disorders such as neurodegenerative diseases, diabetes, cardiovascular diseases, and cancer. They are categorized into various groups based on their chemical structure and include phenolic acids, flavonoids, curcumins, tannins, and quinolones. Their structural variations contribute to their specific beneficial effects on human health. The antioxidant property of phenolic compounds protects against oxidative stress by up-regulation of endogenous antioxidants, scavenging free radicals, and anti-apoptotic activity. Protocatechuic acid (PCA; 3,4-dihydroxy benzoic acid) and protocatechuic aldehyde (PAL; 3,4-dihydroxybenzaldehyde) are naturally occurring polyphenols found in vegetables, fruits, and herbs. PCA and PAL are the primary metabolites of anthocyanins and proanthocyanidins, which have been shown to possess pharmacological actions including antioxidant activity in vitro and in vivo. This review aims to explore the therapeutic potential of PCA and PAL by comprehensively summarizing their pharmacological properties reported to date, with an emphasis on their mechanisms of action and biological properties.

Protocatechuic aldehyde protects cardiomycoytes against ischemic injury via regulation of nuclear pyruvate kinase M2

Rescuing cells from stress damage emerges a potential therapeutic strategy to combat myocardial infarction. Protocatechuic aldehyde (PCA) is a major phenolic acid in Chinese herb Danshen (Salvia miltiorrhiza root). This study investigated whether PCA regulated nuclear pyruvate kinase isoform M2 (PKM2) function to protect cardiomyocytes. In rats subjected to isoprenaline, PCA attenuated heart injury and protected cardiomyocytes from apoptosis. Through DARTS and CETSA assays, we identified that PCA bound and promoted PKM2 nuclear translocation in cardiomyocytes exposed to oxygen/glucose deprivation (OGD). In the nucleus, PCA increased the binding of PKM2 to β-catenin via preserving PKM2 acetylation, and the complex, in cooperation with T-cell factor 4 (TCF4), was required for transcriptional induction of genes encoding anti-apoptotic proteins, contributing to rescuing cardiomyocyte survival. In addition, PCA ameliorated mitochondrial dysfunction and prevented mitochondrial apoptosis dependent on PKM2. Consistently, PCA increased the binding of PKM2 to β-catenin, improved heart contractive function, normalized heart structure and attenuated oxidative damage in mice subjected to artery ligation, but the protective effects were lost in Pkm2-deficient heart. Together, we showed that PCA regulated nuclear PKM2 function to rescue cardiomyocyte survival via β-catenin/TCF4 signaling cascade, suggesting the potential of pharmacological intervention of PKM2 shuttle to protect the heart.

Gallic Acid Induces Neural Stem Cell Differentiation into Neurons and Proliferation through the MAPK/ERK Pathway

Neural stem cell (NSC) differentiation and proliferation are important biological processes in the cerebral neural network. However, these two abilities of NSCs are limited. Thus, the induction of differentiation and/or proliferation through the administration of plant-derived small-molecule compounds could be used to repair damaged neural networks. The present study reported that gallic acid (GA), an important phenolic acid found in tea, selectively caused NSCs to differentiate into immature neurons and promoted NSC proliferation by activating the mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) pathway. In addition, it was found that 3,4-dihydroxybenzoic acid was the main active structure exhibiting neurotrophic activity. The substitution of the carboxyl group on the benzene ring with the ester group may promote differentiation based on the structure of 3,4-dihydroxybenzoic acid. Furthermore, the introduction of the 5-hydroxyl group may promote proliferation. The present study identified that GA can promote the differentiation and proliferation of NSCs in vitro and exert pharmacological activity on NSCs.

Neuroprotective effect of α-pinene self-emulsifying nanoformulation against 6-OHDA induced neurotoxicity on human SH-SY5Y cells and its in vivo validation for anti-Parkinson's effect

Oxidative stress (OS) is involved in the multifaceted pathogenic paradigm of neurodegenerative diseases like Parkinson's disease (PD). Monoterpenes like α-pinene (ALP) is considered to be a therapeutically potent antioxidant agent able to attenuate and scavenge various reactive oxygen species and reactive nitrogen species. The present study aimed to evaluate the in vitro and in vivo neuroprotective effect of α-pinene self-emulsifying nanoformulation (ALP-SENF) for PD. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was done to evaluate the neurotoxic dose of the ALP-SENF; however, the neuroprotective effect was assessed by 6-hydroxydopamine (6-OHDA) induced neurotoxicity model on SH-SY5Y taking NAC (N-acetyl-l-cysteine) as standard. The in vivo anti-Parkinson's activity of the ALP-SENF was compared with that of the plain ALP suspension by using reserpine antagonism and haloperidol-induced Parkinsonism model in rats. Various behavioral tests and biochemical antioxidant enzymes were estimated. The in vitro results revealed that treatment with ALP-SENF at a concentration of 100 and 200 µM was found to show significant neuronal SH-SY5Y cell viability against 50 µM 6-OHDA. ALP-SENF treated animals have seen significant neurobehavioral improvement. Furthermore, the levels of antioxidative enzymes in biochemical test reveals a marked enhancement in the expression of antioxidant enzymes that significantly attenuated the OS induced neurodegeneration. Due to the mechanisms of their antioxidant action, it was probably due to the scavenging of free radicals and the expression of antioxidant enzymes. It also improved neurobehavioral changes induced by reserpine and haloperidol.

Overview of Beneficial Effects of (Poly)phenol Metabolites in the Context of Neurodegenerative Diseases on Model Organisms

The rise of neurodegenerative diseases in an aging population is an increasing problem of health, social and economic consequences. Epidemiological and intervention studies have demonstrated that diets rich in (poly)phenols can have potent health benefits on cognitive decline and neurodegenerative diseases. Meanwhile, the role of gut microbiota is ever more evident in modulating the catabolism of (poly)phenols to dozens of low molecular weight (poly)phenol metabolites that have been identified in plasma and urine. These metabolites can reach circulation in higher concentrations than parent (poly)phenols and persist for longer periods of time. However, studies addressing their potential brain effects are still lacking. In this review, we will discuss different model organisms that have been used to study how low molecular weight (poly)phenol metabolites affect neuronal related mechanisms gathering critical insight on their potential to tackle the major hallmarks of neurodegeneration.

FOXO and related transcription factors binding elements in the regulation of neurodegenerative disorders

Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and others, are characterized by progressive loss of neuronal cells, which causes memory impairment and cognitive decline. Mounting evidence demonstrated the possible implications of diverse biological processes, namely oxidative stress, mitochondrial dysfunction, aberrant cell cycle re-entry, post-translational modifications, protein aggregation, impaired proteasome dysfunction, autophagy, and many others that cause neuronal cell death. The condition worsens as there is no effective treatment for such diseases due to their complex pathogenesis and mechanism. Mounting evidence demonstrated the role of regulatory transcription factors, such as NFκβ, FoxO, Myc, CREB, and others that regulate the biological processes and diminish the disease progression and pathogenesis. Studies demonstrated that forkhead box O (FoxO) transcription factors had been implicated in the regulation of aging and longevity. Further, the functions of FoxO proteins are regulated by different post-translational modifications (PTMs), namely acetylation, and ubiquitination. Various studies concluded that FoxO proteins exert both neuroprotective and neurotoxic properties depending on their regulation mechanism and activity in the brain. Thus, understanding the nature of FoxO expression and activity in the brain will help develop effective therapeutic strategies. Herein, firstly, we discuss the role of FoxO protein in cell cycle regulation and cell proliferation, followed by the regulation of FoxO proteins through acetylation and ubiquitination. We also briefly explain the activity and expression pattern of FoxO proteins in the neuronal cells and explain the mechanism through which FoxO proteins are rescued from oxidative stress-induced neurotoxicity. Later on, we present a detailed view of the implication of FoxO proteins in neurodegenerative disease and FoxO proteins as an effective therapeutic target.

Protein hydrolysates from Pleurotus geesteranus obtained by simulated gastrointestinal digestion exhibit neuroprotective effects in H2 O2 -injured PC12 cells

Neurodegenerative diseases are considered to be among the diseases most threatening to human beings. Increasing evidence shows that antioxidant hydrolysates/peptides with neuroprotective effects may relieve neurodegenerative diseases. However, related research in mushrooms, one of the richest sources of antioxidant hydrolysates/peptides, is in its infancy. Therefore, the in vitro neuroprotective effects of protein hydrolysates from Pleurotus geesteranus were researched in this study. Proteins were extracted from P. geesteranus and then hydrolyzed by simulated gastrointestinal digestion. The neuroprotective effects of the protein hydrolysates were evaluated by H₂ O₂ -injured PC12 cells. The hydrolysates showed a superior antioxidative ability and had a higher abundance of hydrophobic amino acids (e.g., leucine, alanine, and phenylalanine). Neither cytotoxicity nor the increase of ROS in PC12 cells was observed under treatment with the hydrolysates. However, pre-treatment with the hydrolysates in PC12 cells, which were then injured by H₂ O₂ , markedly attenuated ROS generation and enhanced the activities and mRNA expression of the endogenous antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)), leading to a 26.68% increase in cell viability. The hydrolysates exhibited strong neuroprotective activity in H₂ O₂ -injured PC12 cells, possibly by reducing ROS generation and enhancing the activity of the antioxidant enzymatic system. PRACTICAL APPLICATIONS: Antioxidant hydrolysates with neuroprotection were obtained from Pleurotus geesteranus proteins by simulating gastrointestinal digestion, which exhibited an excellent pre-protective effect in oxidatively damaged PC12 cells. Further study showed that hydrolysates pre-protection may exert antioxidant activities not only as an exogenous antioxidant to scavenge ROS but also as a gene regulator to modulate the endogenous antioxidant enzymes gene expression. These results indicated that the potential of antioxidant peptides, derived from P. geesteranus through gastrointestinal digestion, could serve as a source of bioactive molecules in the prevention, relief or even treatment of neurodegenerative disorders.

Mechanisms and Neuroprotective Activities of Stigmasterol Against Oxidative Stress-Induced Neuronal Cell Death via Sirtuin Family

Background: Accumulating studies have confirmed that oxidative stress leads to the death of neuronal cells and is associated with the progression of neurodegenerative diseases, including Alzheimer's disease (AD). Despite the compelling evidence, there is a drawback to the use of the antioxidant approach for AD treatment, partly due to limited blood-brain barrier (BBB) permeability. Phytosterol is known to exhibit BBB penetration and exerts various bioactivities such as antioxidant and anticancer effects, and displays a potential treatment for dyslipidemia, cardiovascular disease, and dementia. Objective: In this study, the protective effects of stigmasterol, a phytosterol compound, on cell death induced by hydrogen peroxide (H2O2) were examined in vitro using human neuronal cells (SH-SY5Y cells). Methods: MTT assay, reactive oxygen species measurement, mitochondrial membrane potential assay, apoptotic cell measurement, and protein expression profiles were performed to determine the neuroprotective properties of stigmasterol. Results: H2O2 exposure significantly increased the levels of reactive oxygen species (ROS) within the cells thereby inducing apoptosis. On the contrary, pretreatment with stigmasterol maintained ROS levels inside the cells and prevented oxidative stress-induced cell death. It was found that pre-incubation with stigmasterol also facilitated the upregulation of forkhead box O (FoxO) 3a, catalase, and anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) in the neurons. In addition, the expression levels of sirtuin 1 (SIRT1) were also increased while acetylated lysine levels were decreased, indicating that SIRT1 activity was stimulated by stigmasterol, and the result was comparable with the known SIRT1 activator, resveratrol. Conclusion: Taken together, these results suggest that stigmasterol could be potentially useful to alleviate neurodegeneration induced by oxidative stress.

A novel acylated flavonol tetraglycoside and rare oleanane saponins with a unique acetal-linked dicarboxylic acid substituent from the xero-halophyte Bassia indica

In recent years, the scientific interest and particularly the economic significance of halophytic plants has been highly demanding due to the medicinal and nutraceutical potential of its bioactive compounds. A xero-halophyte Bassia indica is deemed to be a very cheap source of natural entities without chemical or biological investigation. In this context, a new acylated flavonol tetraglycoside, kaempferol-3-O-β-d-glucopyranosyl-(1→6)-O-[β-D-galactopyranosyl-(1→3)-2-O-trans-feruloyl-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (14), together with rare occurring flavonol triglycoside, isorhamnetin-3-O-β-d-glucopyranosyl-(1→6)-O-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (15), were isolated from the aqueous methanol extract of the aerial parts of B. indica. The study also reported an optimal separation and characterization of a new seco-glycosidic oleanane saponin with 2'R,3'S stereocenters, identified as (2'R,3'S)-3-O-[2'-hydroxy-3'-(2"-O-glycolyl)-oxo-propionic acid-β-D-glucuronopyranosyl]-28-O-β-D-glucopyranosyl-olean-12-en-3β-ol-28-oic acid (17), in addition to its derivative, 3-O-[2'-(2"-O-glycolyl)-glyoxylyl-β-D-glucuronopyranosyl]-28-O-β-d-glucopyranosyl-olean-12-en-3β-ol-28-oic acid (16). The structures of all isolated compounds were elucidated based on 1D, 2D NMR, and HR-MS analysis, as well as comparing with similar derivatives published in the literature. Furthermore, thirteen known compounds were isolated and identified as β-sitosterol (1), vanillic acid (2), o-hydroxybenzoic acid (3), р-hydroxybenzoic acid (4), 6,7-dihydroxycoumarin (5), methyl caffeate (6), caffeic acid (7), quercetin (8), uracil (9), thymidine (10), tachioside (11), isorhamnetin-3-O-β-D-glucopyranoside (12), kaempferol-3-O-rutinoside (13). The anticholinesterase activity of all isolated compounds was evaluated.

Luminescent lanthanide complexes for reactive oxygen species biosensing and possible application in Alzheimer's diseases

Histopathological hallmarks of Alzheimer's disease (AD) are intracellular neurofibrillary tangles and extracellular formation of senile plaques composed of the aggregated amyloid-beta peptide along with metal ions (copper, iron or zinc). In addition, oxidative stress is considered as an important factor in the etiology of AD and a multitude of metalloproteins and transporters is affected, leading to metal ion misregulation. Redox-active metal ions (e.g., copper) can catalyze the production of reactive oxygen species (ROS) in the presence of molecular oxygen and a reductant such as ascorbate. The ROS thus produced, in particular the hydroxyl radical which is the most reactive one, may contribute to oxidative stress conditions. Thus, detecting ROS in vivo or in biological models of AD is of interest for better understanding AD etiology. The use of biocompatible and highly specific and sensitive probes is needed for such a purpose, since ROS are transient species whose steady-state concentrations are very low. Luminescent lanthanide complexes are sensitive probes that can meet these criteria. The present review focuses on the recent advances in the use of luminescent lanthanide complexes for ROS biosensing. It shows why the use of luminescent lanthanide complexes is of particular interest for selectively detecting ROS ( O 2 · - , HO^• , ¹ O₂ , H₂ O₂ , etc.) in biological samples in the µM-nM range. It particularly focuses on the most recent strategies and discusses what could be expected with the use of luminescent lanthanide complexes for better understanding some of the molecular mechanisms underlying the development of Alzheimer's disease.

Potential Antioxidant and Anti-Inflammatory Effects of Spilanthes acmella and Its Health Beneficial Effects: A Review

Oxidative stress and inflammation are two common risk factors of various life-threatening disease pathogenesis. In recent years, medicinal plants that possess antioxidant and anti-inflammatory activities were extensively studied for their potential role in treating and preventing diseases. Spilanthes acmella (S. acmella), which has been traditionally used to treat toothache in Malaysia, contains various active metabolites responsible for its anti-inflammatory, antiseptic, and anesthetic bioactivities. These bioactivities were attributed to bioactive compounds, such as phenolic, flavonoids, and alkamides. The review focused on the summarization of in vitro and in vivo experimental reports on the antioxidant and anti-inflammatory actions of S. acmella, as well as how they contributed to potential health benefits in lowering the risk of diseases that were related to oxidative stress. The molecular mechanism of S. acmella in reducing oxidative stress and inflammatory targets, such as inducible nitric oxide synthase (iNOS), transcription factors of the nuclear factor-κB family (NF-κB), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) signaling pathways were discussed. Besides, the antioxidant potential of S. acmella was measured by total phenolic content (TPC), total flavonid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide anion radical scavenging (SOD) and thiobarbituric acid reactive substance (TBARS) assays. This review revealed that S. acmella might have a potential role as a reservoir of bioactive agents contributing to the observed antioxidant, anti-inflammatory, and health beneficial effects.

Morroniside protects OLN-93 cells against H2O2-induced injury through the PI3K/Akt pathway-mediated antioxidative stress and antiapoptotic activities

Neurodegenerative disorders, including spinal cord injury (SCI), result in oxidative stress-induced cell damage. Morroniside (MR), a major active ingredient of the Chinese herb Shan Zhu Yu, has been shown to ameliorate oxidative stress and inflammatory response. Our previous study also confirmed that morroniside protects SK-N-SH cell line (human neuroblastoma cells) against oxidative impairment. However, it remains unclear whether MR also plays a protective role for oligodendrocytes that are damaged following SCI. The present study investigated the protective effects of MR against hydrogen peroxide (H₂O₂)-induced cell death in OLN-93 cells. MR protected OLN-93 cells from H₂O₂-induced injury, attenuated H₂O₂-induced increase in reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and blocked the reduction of mitochondrial membrane potential (MMP) induced by H2O2. MR enhanced the activity of the antioxidant enzyme superoxide dismutase (SOD) and suppressed H₂O₂-induced downregulation of the antiapoptotic protein Bcl-2 and activation of the proapoptotic protein caspase-3. Finally, we found that LY294002, a specific inhibitor of the PI3K/Akt pathway, inhibited the protective effect of MR against H₂O₂-induced OLN-93 cell injury in the MTT and TUNEL assays. LY294002 also inhibited the expression of SOD and Bcl-2, and increased the expression of iNOS and c-caspase-3 induced by MR treatment. MR exerts protective effects against H₂O₂-induced OLN-93 cell injury through the PI3K/Akt signaling pathway-mediated antioxidative stress and antiapoptotic activities. MR may provide a potential strategy for SCI treatment or other related neurodegeneration.

Sesamin and sesamol attenuate H2O2-induced oxidative stress on human neuronal cells via the SIRT1-SIRT3-FOXO3a signaling pathway

Background: An imbalance of free radicals and antioxidant defense systems in physiological processes can result in protein/DNA damage, inflammation, and cellular apoptosis leading to neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Sesamin and sesamol, compounds derived from sesame seeds and oil, have been reported to exert various pharmacological effects, especially antioxidant activity. However, their molecular mechanisms against the oxidative stress induced by exogenous hydrogen peroxide (H₂O₂) remain to be elucidated. Aim: In this study, neuroprotective effects of sesamin and sesamol on H₂O₂-induced human neuroblastoma (SH-SY5Y) cell death and possible signaling pathways in the cells were explored. Methods: MTT assay and flow cytometry were conducted to determine cell viability and apoptotic profiles of neuronal cells treated with sesamin and sesamol. Carboxy-DCFDA assay was used to measure reactive oxygen species (ROS). Moreover, Western blot analysis was performed to investigate protein profiles associated with neuroprotection. Results: Pretreatment of the cells with 1 µM of sesamin and sesamol remarkably reduced the SH-SY5Y cell death induced by 400 µM H₂O₂ as well as the intracellular ROS production. Moreover, the molecular mechanisms underlying neuroprotection of the compounds were associated with activating SIRT1-SIRT3-FOXO3a expression, inhibiting BAX (proapoptotic protein), and upregulating BCL-2 (anti-apoptotic protein). Conclusion: The findings suggest that sesamin and sesamol are compounds that potentially protect neuronal cells against oxidative stress similar to that of the resveratrol, the reference compound. These antioxidants are thus of interest for further investigation in in vivo models of neuroprotection.

Neuroprotective Potential of Verbascoside Isolated from Acanthus mollis L. Leaves through Its Enzymatic Inhibition and Free Radical Scavenging Ability

The phenomenon of today’s ageing population has increased interest in the search for new active substances that delay the onset and development of neurodegenerative diseases. In this respect, the search for natural compounds, mainly phenolic compounds, with neuroprotective activity has become the focus of growing interest. Verbascoside is a phenylethanoid that has already presented several pharmacological activities. The purpose of this study is to isolate and identify verbascoside from Acanthus mollis leaves. Consequently, its neuroprotective ability through enzymatic inhibition and free radical scavenging ability has been analyzed both in vitro and in cell culture assays. The antioxidant capacity of verbascoside was evaluated in vitro through total antioxidant capacity, DPPH^•, ^•OH, and O₂^•—scavenging activity assays. The effect of verbascoside on intracellular reactive oxygen species (ROS) levels of HepG2 and SH-SY5Y cell lines was studied in normal culture and under induced oxidative stress. The inhibitory ability of the phenylethanoid against several enzymes implied in neurodegenerative diseases (tyrosinase, MAO-A, and AChE) was analyzed in vitro. Verbascoside neuroprotective activity is at least in part related to its free radical scavenging ability. The effect of verbascoside on ROS production suggests its potential in the prevention of harmful cell redox changes and in boosting neuroprotection.

Polyphenols from the flower of Hibiscus syriacus Linn ameliorate neuroinflammation in LPS-treated SH-SY5Y cell

The flower of Hibiscus syriacus Linn is a well-known traditional Chinese medicine (TCM) and health food in China, which has been used to treat dysentery, vaginal discharge, and hemorrhoids. In this study, five polyphenols (compounds 1-5) and five fatty acids (compounds 6-10) were isolated from the ethanol extract of the flower of H. syriacus. The isolated compounds were characterized by spectroscopic techniques. Polyphenols, an important type of natural product, have variety of biological activities. Here, we employed LPS or H₂O₂-treated SH-SY5Y cell models to test the neuroprotective effect of compounds 1-10. Results found compounds 1-5 (concentration range was around 20 μM on LPS model, concentration range was around 13 μM on H₂O₂ model), not compounds 6-10, exhibited neuroprotective effect in LPS or H₂O₂-treated SH-SY5Y cell. PCR analysis showed that compounds 1-5 can effectively improve the mRNA expression of synapse-related gene and neurotrophic factors (Syp, NGF and BDNF) in LPS-treated SH-SY5Y cell. In addition, compounds 1-5 decreased the levels of ROS and MDA and increased the activities of SOD, GSH-Px and CAT in LPS-treated SH-SY5Y cell. Furthermore, compounds 1-5 inhibited neuroinflammation (TNF-α, IL-1β and IL-6) in LPS-treated SH-SY5Y cell. In conclusion, the polyphenols in the flower of H. syriacus could be a promising candidate for preventive effect of neuroinflammation.

The pivotal role of SUMO-1-JNK-Tau axis in an in vitro model of oxidative stress counteracted by the protective effect of curcumin

Oxidative stress is a toxic cellular condition, strictly related to inflammation and known to be a common feature of many neurodegenerative diseases. The imbalanced redox state modifies several molecular processes including protein SUMOylation, JNK and Tau protein activation, important actors in Alzheimer's disease. In this study, we showed a strong interaction among SUMO-1-JNK-Tau proteins and their molecular targets in an in vitro model (SHSY5Y cell line) of oxidative stress in which a significant reduction of cell viability and an augmented cell death was induced by increased doses of H2O2. The evoked oxidative stress led to a deficiency in the degradation system showing altered levels of Caspase-3, LC3BII/I and Ubiquitin. Curcumin, a natural compound with anti-oxidant and anti-inflammatory effects, demonstrated to tackle oxidative stress re-equilibrating SUMO-1, JNK and Tau functions. Importantly, 5 μM of curcumin induced an efficient recovery of cell viability, a reduction of cell death and a normalization of altered protein degradation marker levels. Interestingly, we found that H2O2 treatment induced a strong co-localization of SUMO-1-p-JNK-Tau proteins in nuclear bodies (NBs) and that curcumin was able to reduce these nuclear aggregates. These results highlight the SUMO-1-JNK-Tau axis key role in oxidative stress and the protective effect of curcumin against this pathological event, focusing on the importance of SUMO/deSUMOylation balance to regulate essential cellular processes.

New benzimidazole-aldehyde hybrids as neuroprotectors with hypochlorite and superoxide radical-scavenging activity

BACKGROUND

Many neurodegenerative disorders include oxidative stress-mediated pathology. Melatonin and its metabolites act as endogenous reactive oxygen species (ROS) scavengers and antioxidants. N,N'-Disubstituted benzimidazole-2-thiones with extended side chains could exert antioxidant and neuroprotective properties due to structural similarities to melatonin.

METHODS

The toxicological potential of the compounds was evaluated by monitoring the synaptosomal viability and the levels of reduced glutathione (GSH) in isolated rat brain synaptosomes. The neuroprotective effects were assessed in vitro in a model of 6-hydroxydopamine (6-OHDA)-induced neurotoxicity. The capability to decrease superoxide anion radical and hypochlorite was evaluated by luminol-dependent chemiluminescent assays.

RESULTS

Compounds 5-7 containing residues of veratraldehyde, vanillin, and syringaldehyde at concentration 250 μM, preserved at the highest degree the synaptosomal viability and GSH levels. Further screening of compounds 5-7 at lower concentrations of 100 μM, 10 μM, and 1 μM, respectively, demonstrated that 6 and 7 do not show any toxicity within this concentration range. In the model of 6-OHDA-induced oxidative stress, 6 revealed concentration-dependent, neuroprotective, and antioxidant activities similar to melatonin. All the three compounds demonstrated ability to decrease the chemiluminescent scavenging index (CL-SI) in the hypochlorite containing system. In the superoxide system, the hydrazones exhibited different effects on the signal.

CONCLUSIONS

Our studies suggest that the benzimidazole-aldehyde hybrids act as direct ROS scavengers and membranes' stabilizers against free radicals. Thus, they play a role in the antioxidative defense system and have a promising potential as therapeutic neuroprotective agents for the treatment of neurodegenerative disorders.

Inhibitory Effects of Walnut (Juglans regia) Peptides on Neuroinflammation and Oxidative Stress in Lipopolysaccharide-Induced Cognitive Impairment Mice

Increasing level of inflammation and oxidative stress could lead to memory impairment. The purpose of this study was to determine the neuroprotective effects of walnut peptides against memory deficits induced by lipopolysaccharide (LPS) in mice and further to explore the underlying anti-inflammatory mechanisms against LPS-elicited inflammation in BV-2 cells. Results showed that walnut protein hydrolysate (WPH) and its low-molecular-weight fraction (WPHL) could ameliorate the memory deficits induced by LPS via normalizing the inflammatory response and oxidative stress in brain, especially WPHL. Furthermore, 18 peptides with anti-inflammatory activities on LPS-activated BV-2 cells were identified from WPHL and it was found that Trp, Gly, and Leu residues in peptides might contribute to the anti-inflammation. Meanwhile, the strong anti-inflammatory effects of LPF, GVYY, and APTLW might be related to their hydrophobic and aromatic amino acid residues as well. LPF, GVYY, and APTLW could reduce the content of proinflammatory mediators and cytokines by downregulating related enzyme expressions and mRNA expressions. Additionally, ROS and mitochondria homeostasis might also contribute to their anti-inflammatory effects.

Protocatechuic acid inhibits inflammatory responses in LPS-activated BV2 microglia via regulating SIRT1/NF-κB pathway contributed to the suppression of microglial activation-induced PC12 cell apoptosis

SIRT1 exhibits inhibitory effects on microglial activation-induced neurodegeneration. Regulating SIRT1 may become a novel approach for curing neurodegenerative diseases. Protocatechuic acid (PA), a phenolic acid, has anti-neuroinflammatory effects. The effect of PA on SIRT1 in activated microglia remains unknown. Here, we examined whether PA has anti-inflammatory effects against microglial activation-induced neuronal cell death via regulating SIRT1 in microglia. We found that PA inhibited the release of inflammatory mediators in LPS-activated BV2 microglia via the SIRT1/NF-κB pathway and thereby attenuated microglial activation-induced PC12 cell apoptosis. This suggests that SIRT1 mediates the anti-neuroinflammatory effects of PA to ameliorate microglial activation-induced neuron death.

Profiles and neuroprotective effects of Lycium ruthenicum polyphenols against oxidative stress-induced cytotoxicity in PC12 cells

Lycium ruthenicum Murr. (L. ruthenicum Murr.) is one of the perennial shrubs, which is commonly consumed as ethnic medicine and nutraceutical food. Herein, we detected eight polyphenols (including protocatechuic acid, catechin, p-coumaric acid, rutin, quercetin, syringic acid, caffeic acid, and ferulic acid) from Lycium ruthenicum. Furthermore, this study researched the potential neuroprotective mechanism of L. ruthenicum Murr. polyphenols (LRP) on PC12 cells under H₂ O₂ -induced oxidative stress. The results showed that pretreatment with LRP significantly mitigates H₂ O₂ -induced cytotoxicity in a dose-dependent manner for PC12 cells. LRP pretreatment also ameliorated the generation of intracellular reactive oxygen species and restored mitochondrial membrane potential as well as prevented the activation of caspase-3, caspase-8, and caspase-9 on PC12 cells under oxidative stress-induced apoptosis. This suggests that LRP will be a promising, safe candidate for delaying the onset and progress of neurodegenerative diseases associated with oxidative stress. PRACTICAL APPLICATIONS: Lycium ruthenicum Murr. belonging to the Solanaceae family, which is widespread throughout the Qinghai Tibet Plateau. It is one of the well-known perennial shrubs. Moreover, it is well known for containing a considerable amount of polyphenols. It has been reported that Lycium ruthenicum has anti-inflammatory, antihyperlipidemic, and antioxidative activities. Our results suggest that Lycium ruthenicum rich in polyphenols could contribute to delay in the onset and progress of neurodegenerative diseases associated with oxidative stress. Hence, LRP could be labeled as a neuroprotective food, ingredient or supplement in the formulation of food products for the population under oxidative stress induced related neurological changes.

7-O-Esters of taxifolin with pronounced and overadditive effects in neuroprotection, anti-neuroinflammation, and amelioration of short-term memory impairment in vivo

Alzheimer's disease (AD) is a multifactorial disease and the most common form of dementia. There are no treatments to cure, prevent or slow down the progression of the disease. Natural products hold considerable interest for the development of preventive neuroprotectants to treat neurodegenerative disorders like AD, due to their low toxicity and general beneficial effects on human health with their anti-inflammatory and antioxidant features. In this work we describe regioselective synthesis of 7-O-ester hybrids of the flavonoid taxifolin with the phenolic acids cinnamic and ferulic acid, namely 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin. The compounds show pronounced overadditive neuroprotective effects against oxytosis, ferroptosis and ATP depletion in the murine hippocampal neuron HT22 cell model. Furthermore, 7-O-cinnamoyltaxifolin and 7-O-feruloyltaxifolin reduced LPS-induced neuroinflammation in BV-2 microglia cells as assessed by effects on the levels of NO, IL6 and TNFα. In all in vitro assays the 7-O-esters of taxifolin and ferulic or cinnamic acid showed strong overadditive activity, significantly exceeding the effects of the individual components and the equimolar mixtures thereof, which were almost inactive in all of the assays at the tested concentrations. In vivo studies confirmed this overadditive effect. Treatment of an AD mouse model based on the injection of oligomerized Aβ_25-35 peptide into the brain to cause neurotoxicity and subsequently memory deficits with 7-O-cinnamoyltaxifolin or 7-O-feruloyltaxifolin resulted in improved performance in an assay for short-term memory as compared to vehicle and mice treated with the respective equimolar mixtures. These results highlight the benefits of natural product hybrids as a novel compound class with potential use for drug discovery in neurodegenerative diseases due to their pharmacological profile that is distinct from the individual natural components.

Neuroprotective effects of urolithin A on H2O2-induced oxidative stress-mediated apoptosis in SK-N-MC cells

BACKGROUND/OBJECTIVES

Oxidative stress causes cell damage and death, which contribute to the pathogenesis of neurodegenerative diseases. Urolithin A (UA), a gut microbial-derived metabolite of ellagitannins and ellagic acid, has high bioavailability and various health benefits such as antioxidant and anti-inflammatory effects. However, it is unknown whether it has protective effects against oxidative stress-induced cell death. We investigated whether UA ameliorates H₂O₂-induced neuronal cell death.

MATERIALS/METHODS

We induced oxidative damage with 300 µM H₂O₂ after UA pretreatment at concentrations of 1.25, 2.5, and 5 µM in SK-N-MC cells. Cytotoxicity and cell viability were determined using the CCK-8 assay. The formation of reactive oxygen species (ROS) was measured using a 2,7-dichlorofluorescein diacetate assay. Hoechst 33342 staining was used to characterize morphological changes in apoptotic cells. The expressions of apoptosis proteins were measured using Western blotting.

RESULTS

UA significantly increased cell viability and decreased intracellular ROS production in a dose-dependent manner in SK-N-MC cells. It also decreased the Bax/Bcl-2 ratio and the expressions of cytochrome c, cleaved caspase-9, cleaved caspase-3, and cleaved PARP. In addition, it suppressed the phosphorylation of the p38 mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

UA attenuates oxidative stress-induced apoptosis via inhibiting the mitochondrial-related apoptosis pathway and modulating the p38 MAPK pathway, suggesting that it may be an effective neuroprotective agent.

Microscopic Viscosity of Neuronal Plasma Membranes Measured Using Fluorescent Molecular Rotors: Effects of Oxidative Stress and Neuroprotection

Molecular mobility in neuronal plasma membranes is a crucial factor in brain function. Microscopic viscosity is an important parameter that determines molecular mobility. This study presents the first direct measurement of the microviscosity of plasma membranes of live neurons. Microviscosity maps were obtained using fluorescence lifetime imaging of environment-sensing dyes termed "molecular rotors". Neurons were investigated both in the basal state and following common neurodegenerative stimuli, excitotoxicity, or oxidative stress. Both types of neurotoxic challenges induced microviscosity decrease in cultured neurons, and oxidant-induced membrane fluidification was counteracted by the wide-spectrum neuroprotectant, the H3 peptide. These results provide new insights into molecular mobility in neuronal membranes, paramount for basic brain function, and suggest that preservation of membrane stability may be an important aspect of neuroprotection in brain insults and neurodegenerative disorders.

Exploring the Antioxidant Effects and Periodic Regulation of Cancer Cells by Polyphenols Produced by the Fermentation of Grape Skin by Lactobacillus plantarum KFY02

Lactobacillus plantarum KFY02 (LP-KFY02) was isolated from naturally fermented yoghurt in Xinjiang. We previously demonstrated that LP-KFY02 has good biological activity in vitro. In this study, LP-KFY02 was used to ferment grape skin, and the LP-KFY02 fermented grape skin extract solution (KFSE) was examined for its antioxidant ability in a human embryonic kidney (293T) cell oxidative damage model caused by H2O2 and its inhibitory effect on human hepatoma (HepG2) cells. The results showed that KFSE reduced the degree of oxidative damage in 293T cells, increased the relevant expression levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and GSH-peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), and decreased the expression levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), and nitric oxide (NO). The expression of genes and proteins of SOD, CAT, GSH, and GSH-Px was up-regulated. In addition, KFSE-induced growth inhibition appeared to be through induction of cell-cycle arrest. This induction was accompanied by a reduction in the expression of cell-cycle genes, such as cyclin-D1 and CDK4. In addition, KFSE induced gene expression of p21, the apoptosis gene wild-type p53 and the caspase family. At the protein expression level, Bax and Caspase-8 were up-regulated, and the inflammatory marker Nuclear Factor Kappa-B (NF-κB) was down-regulated. The fermentation solution polyphenols were separated and identified as epicatechin gallate, coumarin, new chlorogenic acid, rutin, resveratrol, chlorogenic acid, rosmarinic acid, etc. by HPLC. Overall, these results demonstrate that KFSE significantly attenuated oxidative damage in 293T cells and inhibited tumor growth in HepG2 cancer cells, induces cell-cycle arrest and affects proteins involved in cell-cycle regulation and proliferation. This suggests that KFSE may also be explored as a neo-adjuvant to expansion of hepatoma.

Antioxidant-Conjugated 1,2,4-Triazolo[4,3-a]pyrazin-3-one Derivatives: Highly Potent and Selective Human A2A Adenosine Receptor Antagonists Possessing Protective Efficacy in Neuropathic Pain

New 8-amino-6-aryl-1,2,4-triazolo[4,3-a]pyrazin-3-ones were designed to obtain dual antioxidant-human A_2A adenosine receptor (hA_2A AR) antagonists. Two sets of compounds were synthesized, the first featuring phenol rings at the 6-position, the second bearing the lipoyl and 4-hydroxy-3,5-di-tertbut-benzoyl residues appended by different linkers on the 6-phenyl ring. Several new triazolopyrazines (1-21) were potent and selective hA_2A AR antagonists (K_i = 0.17-54.5 nM). Compounds 11, 15, and 21, featuring antioxidant moieties, and compound 12, lacking the antioxidant functionality, reduced oxaliplatin-induced toxicity in microglia cells, the most active being the lipoyl-derivative 15 and the (4-hydroxy-3,5-di-tert-butyl)benzoyl-analogue 21 which were effective in reducing the oxygen free radical level. The lipoyl-derivative 15 was also able to revert oxaliplatin-induced neuropathy in the mouse. In vivo efficacy of 15 makes it a promising neuroprotective agent in oxidative stress-related diseases.

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.

Design, synthesis, and biological activity evaluation of BACE1 inhibitors with antioxidant activity

The proteolytic enzyme β-secretase (BACE1) plays a central role in the synthesis of the pathogenic β-amyloid peptides (Aβ) in Alzheimer's disease (AD), antioxidants could attenuate the AD syndrome and prevent the disease progression. In this study, BACE1 inhibitors (D1-D18) with free radical-scavenging activities were synthesized by molecular hybridization of 2-aminopyridine with natural antioxidants. The biological activity evaluation showed that D1 had obvious inhibitory activity against BACE1, and strong antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS^+• ) assay, which could be used as a lead compound for further study.