Natural Compounds as Beneficial Antioxidant Agents in Neurodegenerative Disorders: A Focus on Alzheimer's Disease

The alphabet of sea fennel: Comprehensive phytochemical characterisation of Croatian populations of Crithmum maritimum L

Extreme environmental conditions affect the synthesis and accumulation of bioactive metabolites in halophytic plants. The aim of this study was to investigate the presence and quantity of key health-promoting phytochemicals in Croatian sea fennel, one of the most popular Mediterranean halophytes with a wide range of uses. The EOs were characterised by a high content of limonene (up to 93%), while the fatty acid profile shows a low content of oleic acid and the presence of valuable linoleic acid (ω-6) and linolenic acid (ω-3) in high percentages. The dominances of lutein and α-tocopherol were also confirmed in all samples. The results confirm the great variability in the chemistry of sea fennel populations in the Mediterranean region, with significant differences in the composition of the Croatian samples compared to the others, as well as the presence and high concentrations of the analysed bioactive compounds that contribute to the plant's health-promoting attributes.

Rosuvastatin attenuates total-tau serum levels and increases expression of miR-124-3p in dyslipidemic Alzheimer's patients: a historic cohort study

microRNAs are candidate diagnostic biomarkers for Alzheimer's disease. This study aimed to compare Silymarin with Rosuvastatin and placebo on total-Tau protein level and expression levels of microRNAs and TGF-β and COX-2 in Alzheimer's patients with secondary dyslipidemia. 36 mild AD patients with dyslipidemia were divided into three groups of 12. The first group received silymarin (140mg), the second group received placebo (140mg), and the third group recieved Rosuvastatin (10mg). Tablets were administered three times a day for Six months. The blood samples of the patients were collected before and after the intervention and the serum was separated. Using the RT-qPCR method, the expression levels of miR-124-3p and miR-125b-5p were assessed, and the serum levels of total-Tau, TGF-β, and COX-2 enzyme were measured using the ELISA method. Data were analyzed with SPSS software. In this study, the level of Δtotal-Tau was significantly lower in the Rosuvastatin group compared to the placebo (P = 0.038). Also, a significant reduction in the level of ΔTGF-β was observed in the Silymarin to Rosuvastatin group (p = 0.046) and ΔmiR-124-3p was significantly increased in the Rosuvastatin compared to the placebo group (p = 0.044). Rosuvastatin outperformed silymarin in decreasing Δtotal-Tau serum levels and enhancing expression of ΔmiR-124-3p, attributed to Rosuvastatin's capacity to lower cholesterol levels and inflammation concurrently. Conversely, silymarin was more effective than Rosuvastatin in reducing levels of ΔTGF-β. Serum miR-124-3p could serve as a promising diagnostic biomarker and a new therapeutic focus in AD.

Assessing the Chemical Composition, Antioxidant and enzyme Inhibitory Effects of Pentapleura subulifera and Cyclotrichium glabrescens Extracts

The Lamiaceae family, encompassing diverse plant species, holds significant value in food, medicine, and cosmetics. Within this family, Pentapleura subulifera and Cyclotrichium glabrescens, relatively unexplored species, were investigated for their chemical composition, antioxidant capacity, and enzyme-inhibiting effects. The chemical composition of hexane, methanolic, and aqueous extracts from P. subulifera and C. glabrescens were analyzed using LC-ESI-MS/MS and the non-polar hexane fraction was investigated via GC-MS. The antioxidant potential of the extracts was determined through radical scavenging, reducing power and metal chelating assays. Additionally, inhibitory activity against six enzymes - acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase - was examined. The aqueous extract of P. subulifera and the methanolic extract of C. glabrescens exhibited elevated phenolic content at 129.47 mg gallic acid equivalent (GAE)/g and 55.97 mg GAE/g, respectively. Chemical profiling of the constituents of the two plant species resulted in the identification of a total of twenty compounds. The majority of which belonged to flavonoids and quinic acid derivatives, primarily concentrated in the methanol and aqueous extracts. Among all antioxidant assays, the aqueous extracts of P. subulifera demonstrated superior antioxidant activity, with the highest recorded activity of 404.93 mg trolox equivalent (TE)/g in the cupric reducing antioxidant capacity (CUPRAC) test. Meanwhile, the hexane extract of C. glabrescens exhibited the highest AChE inhibitory activity at 2.71 mg galanthamine equivalent (GALAE)/g, followed by the methanol extract of P. subulifera at 2.41 mg GALAE/g. These findings unequivocally establish the notable antioxidant and enzyme inhibitory activity of P. subulifera and C. glabrescens extracts, underscoring their potential as a source of valuable natural antioxidants.

Betula pendula Leaf Extract Targets the Interplay between Brain Oxidative Stress, Inflammation, and NFkB Pathways in Amyloid Aβ1-42-Treated Rats

Alzheimer's disease (AD) is known as the primary and most common cause of dementia in the middle-aged and elderly population worldwide. Chemical analyses of B. pendula leaf extract (BPE), performed using spectrophotometric and chromatographic methods (LC/MS), revealed high amounts of polyphenol carboxylic acids (gallic, chlorogenic, caffeic, trans-p-coumaric, ferulic, and salicylic acids), as well as flavonoids (apigenin, luteolin, luteolin-7-O-glucoside, naringenin, hyperoside, quercetin, and quercitrin). Four groups of Wistar rats were used in this experiment (n = 7/group): control (untreated), Aβ1-42 (2 μg/rat intracerebroventricular (i.c.v.), Aβ1-42 + BPE (200 mg/Kg b.w.), and DMSO (10 μL/rat). On the first day, one dose of Aβ1-42 was intracerebroventricularly administered to animals in groups 2 and 3. Subsequently, BPE was orally administered for the next 15 days to group 3. On the 16th day, behavioral tests were performed. Biomarkers of brain oxidative stress Malondialdehyde (MDA), (Peroxidase (PRx), Catalase (CAT), and Superoxid dismutase (SOD) and inflammation (cytokines: tumor necrosis factor -α (TNF-α), Interleukin 1β (IL-1β), and cyclooxygenase-2 (COX 2)) in plasma and hippocampus homogenates were assessed. Various protein expressions (Phospho-Tau (Ser404) (pTau Ser 404), Phospho-Tau (Ser396) (pTau Ser 396), synaptophysin, and the Nuclear factor kappa B (NFkB) signaling pathway) were analyzed using Western blot and immunohistochemistry in the hippocampus. The results show that BPE diminished lipid peroxidation and neuroinflammation, modulated specific protein expression, enhanced the antioxidant capacity, and improved spontaneous alternation behavior, suggesting that it has beneficial effects in AD.

Aerobic exercise combined with chlorogenic acid exerts neuroprotective effects and reverses cognitive decline in Alzheimer's disease model mice (APP/PS1) via the SIRT1/ /PGC-1α/PPARγ signaling pathway

Alzheimer's disease (AD) is a prevalent neurodegenerative disease account for 60-80% of the total number of people with dementia, but its treatment and prevention strategies are still in a long process of exploration. It has been reported that a healthy lifestyle may be an effective non-pharmacological intervention for the prevention and treatment of AD, including increased physical activity and the consumption of polyphenol-rich foods. This study, therefore, investigated the effects of 8 weeks of moderate-intensity aerobic exercise (EX), administration of chlorogenic acid administration (GCA), and a combination of both (EX+GCA) on β-amyloid (Aβ) deposition, inflammatory factors, oxidative stress markers, neuronal damage, and cognitive performance in the brains of AD model mice (APP/PS1) and which signaling pathways may be responsible for these effects. The study used Western blot to detect the expression of signaling pathway-related proteins, enzyme-linked immunosorbent assay to detect the expression of inflammatory factors, hematoxylin-eosin staining to detect hippocampal neuronal morphology, immunohistochemistry to detect changes in Aβ deposition in the hippocampus, an oxidative stress marker kit to detect oxidative stress status and the Morris water maze to detect changes in cognitive performance. This study showed that an 8-week intervention (EX/GCA/EX+GCA) activating the SIRT1/PGC-1α signaling pathway improved oxidative stress, neuroinflammation, Aβ deposition, and cognitive performance in mice. However, there was no obvious difference between the EX and GCA groups. In contrast, the combined EX+GCA intervention was significantly better than phase EX or GCA. Our study suggests that although relief of Aβ deposition, neuroinflammation, oxidative stress, neuronal damage, and cognitive decline could also be achieved with EX or GCA, the combined EX+GCA intervention showed better results. These relief effects on AD-related conditions may be obtained by mediating the activation of the SIRT1/PGC-1α signaling pathway. This study is the first to explore the improvement of AD-related conditions with a combined lifestyle of EX+GCA. This healthy lifestyle could be a candidate option for the treatment of AD.

Neuroprotective effects of hesperetin on H2O2-induced damage in neuroblastoma SH-SY5Y cells

BACKGROUND/OBJECTIVES

Oxidative stress is a fundamental neurodegenerative disease trigger that damages and decimates nerve cells. Neurodegenerative diseases are chronic central nervous system disorders that progress and result from neuronal degradation and loss. Recent studies have extensively focused on neurodegenerative disease treatment and prevention using dietary compounds. Heseperetin is an aglycone hesperidin form with various physiological activities, such as anti-inflammation, antioxidant, and antitumor. However, few studies have considered hesperetin's neuroprotective effects and mechanisms; thus, our study investigated this in hydrogen peroxide (H2O2)-treated SH-SY5Y cells.

MATERIALS/METHODS

SH-SY5Y cells were treated with H2O2 (400 µM) in hesperetin absence or presence (10-40 µM) for 24 h. Three-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays detected cell viability, and 4',6-diamidino-2-phenylindole staining allowed us to observe nuclear morphology changes such as chromatin condensation and apoptotic nuclei. Reactive oxygen species (ROS) detection assays measured intracellular ROS production; Griess reaction assays assessed nitric oxide (NO) production. Western blotting and quantitative polymerase chain reactions quantified corresponding mRNA and proteins.

RESULTS

Subsequent experiments utilized various non-toxic hesperetin concentrations, establishing that hesperetin notably decreased intracellular ROS and NO production in H2O2-treated SH-SY5Y cells (P < 0.05). Furthermore, hesperetin inhibited H2O2-induced inflammation-related gene expression, including interluekin-6, tumor necrosis factor-α, and nuclear factor kappa B (NF-κB) p65 activation. In addition, hesperetin inhibited NF-κB translocation into H2O2-treated SH-SY5Y cell nuclei and suppressed mitogen-activated protein kinase protein expression, an essential apoptotic cell death regulator. Various apoptosis hallmarks, including shrinkage and nuclear condensation in H2O2-treated cells, were suppressed dose-dependently. Additionally, hesperetin treatment down-regulated Bax/Bcl-2 expression ratios and activated AMP-activated protein kinase-mammalian target of rapamycin autophagy pathways.

CONCLUSION

These results substantiate that hesperetin activates autophagy and inhibits apoptosis and inflammation. Hesperetin is a potentially potent dietary agent that reduces neurodegenerative disease onset, progression, and prevention.

Natural Compounds and Healthy Foods: Useful Tools against Onset and Progression of Chronic Diseases

The Special Issue (SI) in Nutrients, titled "Natural Compounds and Healthy Foods: New Strategy to Counteract Chronic Diseases", deals with the beneficial effects of some natural bioactive substances and the relative action mechanisms, providing evidence for the potential to counteract some chronic diseases (CD) [...].

Pharmaceutical prospects of Silymarin for the treatment of neurological patients: an updated insight

Background

Silymarin is a polyphenolic flavonoid complex extricated from dried fruits and seeds of the plant Silybum marianum L. Chemically, it is a mixture of flavonolignan complexes consisting of silybin, isosilybin, silychristin, silydianin, a minor quantity of taxifolin, and other polyphenolic compounds, which possess different bio medicinal values.

Purpose

This review critically looks into the current status, pharmaceutical prospects and limitations of the clinical application of Silymarin for treating neurological disorders. In particular, Silymarin's medicinal properties and molecular mechanisms are focused on providing a better-compiled understanding helpful in its neuro-pharmacological or therapeutic aspects.

Methods

This review was compiled by the literature search done using three databases, i.e., PubMed (Medline), EMBASE and Science Direct, up to January 2023, using the keywords-Silymarin, neurological disorders, cognitive disorders, Type 2 Diabetes, pharmaceutical prospects and treatment. Then, potentially relevant publications and studies (matching the eligible criteria) were retrieved and selected to explain in this review using PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) study flow chart.

Result

Since its discovery, it has been widely studied as a hepatoprotective drug for various liver disorders. However, in the last 10-15 years, several research studies have shown its putative neuroprotective nature against various brain disorders, including psychiatric, neurodegenerative, cognitive, metabolic and other neurological disorders. The main underlying neuroprotective mechanisms in preventing and curing such disorders are the antioxidant, anti-inflammatory, anti-apoptotic, pro-neurotrophic and pro-estrogenic nature of the bioactive molecules.

Conclusion

This review provides a lucid summary of the well-studied neuroprotective effects of Silymarin, its underlying molecular mechanisms and current limitations for its usage during neurological disorders. Finally, we have suggested a future course of action for developing it as a novel herbal drug for the treatment of brain diseases.

Aphanizomenon flos-aquae (AFA) Extract Prevents Neurodegeneration in the HFD Mouse Model by Modulating Astrocytes and Microglia Activation

Obesity and related metabolic dysfunctions are associated with neurodegenerative diseases, such as Alzheimer's disease. Aphanizomenon flos-aquae (AFA) is a cyanobacterium considered a suitable supplement for its nutritional profile and beneficial properties. The potential neuroprotective effect of an AFA extract, commercialized as KlamExtra^®, including the two AFA extracts Klamin^® and AphaMax^®, in High-Fat Diet (HFD)-fed mice was explored. Three groups of mice were provided with a standard diet (Lean), HFD or HFD supplemented with AFA extract (HFD + AFA) for 28 weeks. Metabolic parameters, brain insulin resistance, expression of apoptosis biomarkers, modulation of astrocytes and microglia activation markers, and Aβ deposition were analyzed and compared in the brains of different groups. AFA extract treatment attenuated HFD-induced neurodegeneration by reducing insulin resistance and loss of neurons. AFA supplementation improved the expression of synaptic proteins and reduced the HFD-induced astrocytes and microglia activation, and Aβ plaques accumulation. Together, these outcomes indicate that regular intake of AFA extract could benefit the metabolic and neuronal dysfunction caused by HFD, decreasing neuroinflammation and promoting Aβ plaques clearance.

CGAs-Rich Conilon Coffee Consumption Improves Cognition and Reduces Oxidative Stress in Elderly with Alzheimer's Disease: A Pilot Study

BACKGROUND

The consumption of coffee has been associated with beneficial effects when it comes to Alzheimer's disease (AD). However, to the best of our knowledge, there are no studies on Conilon coffee consumption in elderly people with AD.

OBJECTIVE

Evaluate the effects of Conilon coffee consumption in elderly with AD.

METHODS

The study was carried out with 9 participants who consumed a minimum of 2 cups (200 mL cup) of Conilon coffee per day for 90 days. Cognitive assessment was done before (T0) and after 90 days (T90). Blood analysis was conducted at T0 and T90, as well as the assessment of advanced oxidation protein products (AOPP) and thiobarbituric acid reactive species (TBARS). The levels of chlorogenic acids and caffeine in the coffee beverage were quantified by liquid chromatography.

RESULTS

During the treatment, the participants consumed at least 550 mg and 540 mg of CGAs and caffeine, respectively. A significant improvement in cognition between T0 and T90 was observed as per MMSE, CTP, and clock drawing tests. Furthermore, there was a significant reduction in AOPP (37%) and TBARS (60%), indicating a reduction in oxidative stress. The consumption of the coffee did not significantly alter any blood parameter, which confirms the safety of the coffee treatment during the 90 days.

CONCLUSIONS

Our study demonstrated for the first time that regular consumption of coffee with high amounts of CGAs and caffeine improves cognitive functions and reduces oxidative stress, without altering blood parameters that indicate possible signs of toxicity in classical target organs.

Marine Natural Products from the Russian Pacific as Sources of Drugs for Neurodegenerative Diseases

Neurodegenerative diseases are growing to become one of humanity's biggest health problems, given the number of individuals affected by them. They cause enough mortalities and severe economic impact to rival cancers and infections. With the current diversity of pathophysiological mechanisms involved in neurodegenerative diseases, on the one hand, and scarcity of efficient prevention and treatment strategies, on the other, all possible sources for novel drug discovery must be employed. Marine pharmacology represents a relatively uncharted territory to seek promising compounds, despite the enormous chemodiversity it offers. The current work discusses one vast marine region-the Northwestern or Russian Pacific-as the treasure chest for marine-based drug discovery targeting neurodegenerative diseases. We overview the natural products of neurological properties already discovered from its waters and survey the existing molecular and cellular targets for pharmacological modulation of the disease. We further provide a general assessment of the drug discovery potential of the Russian Pacific in case of its systematic development to tackle neurodegenerative diseases.

Manipulation of the diet-microbiota-brain axis in Alzheimer's disease

Several studies investigating the pathogenesis of Alzheimer's disease have identified various interdependent constituents contributing to the exacerbation of the disease, including Aβ plaque formation, tau protein hyperphosphorylation, neurofibrillary tangle accumulation, glial inflammation, and the eventual loss of proper neural plasticity. Recently, using various models and human patients, another key factor has been established as an influential determinant in brain homeostasis: the gut-brain axis. The implications of a rapidly aging population and the absence of a definitive cure for Alzheimer's disease have prompted a search for non-pharmaceutical tools, of which gut-modulatory therapies targeting the gut-brain axis have shown promise. Yet multiple recent studies examining changes in human gut flora in response to various probiotics and environmental factors are limited and difficult to generalize; whether the state of the gut microbiota in Alzheimer's disease is a cause of the disease, a result of the disease, or both through numerous feedback loops in the gut-brain axis, remains unclear. However, preliminary findings of longitudinal studies conducted over the past decades have highlighted dietary interventions, especially Mediterranean diets, as preventative measures for Alzheimer's disease by reversing neuroinflammation, modifying the intestinal and blood-brain barrier (BBB), and addressing gut dysbiosis. Conversely, the consumption of Western diets intensifies the progression of Alzheimer's disease through genetic alterations, impaired barrier function, and chronic inflammation. This review aims to support the growing body of experimental and clinical data highlighting specific probiotic strains and particular dietary components in preventing Alzheimer's disease via the gut-brain axis.

Protective effects of silibinin on LPS-induced inflammation in human periodontal ligament cells

Clinically, periodontitis is a chronic nonspecific inflammation that leads to damaged teeth and their supporting gum tissues. Although many studies on periodontitis have been conducted, therapy with natural products is still rare. Silibinin has been proven to have anti-inflammatory and antioxidant activities. However, the effects of silibinin on lipopolyssacharide (LPS)-induced inflammation in periodontal ligaments (PDLs) have not yet been investigated. In this study, the PDLs were treated with silibinin (10, 20, and 40 μM) in the presence of LPS. The results showed that silibinin treatment reduced the levels of NO, PGE2, IL-6, TNF-α, MMP-1, and MMP-3 and enhanced the activities of superoxide dismutase (SOD) and glutathione (GSH). Moreover, silibinin treatment downregulated RANKL levels and upregulated OPG and ALP levels. In summary, silibinin protected PDLs against LPS-induced inflammation, oxidative stress, and osteogenic differentiation.

Development of HPTLC method for the simultaneous estimation of quercetin, curcumin, and ascorbic acid in herbal formulations

Antioxidants can scavenge free radicals in the human body and have been associated with a protective effect on the human body against a variety of diseases. As a part of normal cellular function, free radical production occurs continuously within the body at a cellular level. Excess-free radical production from endogenous or exogenous sources may result in a variety of diseases. Vitamins (A, C, and E), carotenoids, polyphenols, and flavonoids are some examples of common natural antioxidants. Among the different antioxidants quercetin, curcumin, and ascorbic acids have been extensively studied, and numerous reports on their antioxidant activity are available in the literature. Antioxidants are regarded as a key player in the current pandemic situation, and they play a key role as a preventive and controlling tool. There are a variety of herbal formulations and immune booster therapies available, many of which claim to contain various antioxidants and are effective against covid-19. Numerous herbal formulations and immune booster therapies are available and claimed to have different antioxidants and other constituents. In the present study simple, rapid, accurate, precise, and sensitive high-performance thin-layer chromatographic analytical method was developed for simultaneous estimation of quercetin, curcumin, and ascorbic acid. The developed method can effectively employ for different polyherbal formulations. The developed method was validated according to ICH guidelines. In the present study, an aluminum plate precoated with 60F 254 silica gel was used as a stationary phase whereas chloroform: ethyl acetate: formic acid (6:6:2.5 v/v/v) was used as a mobile phase. Chromatographic detection was performed with a Camag TLC scanner at 265 nm. The linearity range for the proposed method was found to be 500–1000 ng/band for all three analytes. The antioxidant potentiality of selected antioxidants was evaluated by an optimized UV visible spectroscopic-reducing power method. The reducing power method was optimized for the concentration and volume of reagent, incubation temperature, and time. The results of the study revealed that quercetin is having the best antioxidant potential compared to curcumin and ascorbic acid.

Multi-Target Mechanisms of Phytochemicals in Alzheimer’s Disease: Effects on Oxidative Stress, Neuroinflammation and Protein Aggregation

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by a tangle-shaped accumulation of beta-amyloid peptide fragments and Tau protein in brain neurons. The pathophysiological mechanism involves the presence of Aβ-amyloid peptide, Tau protein, oxidative stress, and an exacerbated neuro-inflammatory response. This review aims to offer an updated compendium of the most recent and promising advances in AD treatment through the administration of phytochemicals. The literature survey was carried out by electronic search in the following specialized databases PubMed/Medline, Embase, TRIP database, Google Scholar, Wiley, and Web of Science regarding published works that included molecular mechanisms and signaling pathways targeted by phytochemicals in various experimental models of Alzheimer’s disease in vitro and in vivo. The results of the studies showed that the use of phytochemicals against AD has gained relevance due to their antioxidant, anti-neuroinflammatory, anti-amyloid, and anti-hyperphosphorylation properties of Tau protein. Some bioactive compounds from plants have been shown to have the ability to prevent and stop the progression of Alzheimer’s.

Protection against Paraquat-Induced Oxidative Stress by Curcuma longa Extract-Loaded Polymeric Nanoparticles in Zebrafish Embryos

The link between oxidative stress and environmental factors plays an important role in chronic degenerative diseases; therefore, exogenous antioxidants could be an effective alternative to combat disease progression and/or most significant symptoms. Curcuma longa L. (CL), commonly known as turmeric, is mostly composed of curcumin, a multivalent molecule described as having antioxidant, anti-inflammatory and neuroprotective properties. Poor chemical stability and low oral bioavailability and, consequently, poor absorption, rapid metabolism, and limited tissue distribution are major restrictions to its applicability. The advent of nanotechnology, by combining nanosacale with multi-functionality and bioavailability improvement, offers an opportunity to overcome these limitations. Therefore, in this work, poly-Ɛ-caprolactone (PCL) nanoparticles were developed to incorporate the methanolic extract of CL, and their bioactivity was assessed in comparison to free or encapsulated curcumin. Their toxicity was evaluated using zebrafish embryos by applying the Fish Embryo Acute Toxicity test, following recommended OECD guidelines. The protective effect against paraquat-induced oxidative damage of CL extract, free or encapsulated in PCL nanoparticles, was evaluated. This herbicide is known to cause oxidative damage and greatly affect neuromotor functions. The overall results indicate that CL-loaded PCL nanoparticles have an interesting protective capacity against paraquat-induced damage, particularly in neuromuscular development that goes well beyond that of CL extract itself and other known antioxidants.

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions

Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement in the pathophysiology of inflammatory diseases, metabolic disorders, and neurological defects. Free radicals increase the concentration of reactive oxygen and nitrogen species in the biological system through different endogenous sources and thus increased the overall oxidative stress. An increase in oxidative stress causes cell death through different signaling mechanisms such as mitochondrial impairment, cell-cycle arrest, DNA damage response, inflammation, negative regulation of protein, and lipid peroxidation. Thus, an appropriate balance between free radicals and antioxidants becomes crucial to maintain physiological function. Since the 1brain requires high oxygen for its functioning, it is highly vulnerable to free radical generation and enhanced ROS in the brain adversely affects axonal regeneration and synaptic plasticity, which results in neuronal cell death. In addition, increased ROS in the brain alters various signaling pathways such as apoptosis, autophagy, inflammation and microglial activation, DNA damage response, and cell-cycle arrest, leading to memory and learning defects. Mounting evidence suggests the potential involvement of micro-RNAs, circular-RNAs, natural and dietary compounds, synthetic inhibitors, and heat-shock proteins as therapeutic agents to combat neurological diseases. Herein, we explain the mechanism of free radical generation and its role in mitochondrial, protein, and lipid peroxidation biology. Further, we discuss the negative role of free radicals in synaptic plasticity and axonal regeneration through the modulation of various signaling molecules and also in the involvement of free radicals in various neurological diseases and their potential therapeutic approaches. The primary cause of free radical generation is drug overdosing, industrial air pollution, toxic heavy metals, ionizing radiation, smoking, alcohol, pesticides, and ultraviolet radiation. Excessive generation of free radicals inside the cell R1Q1 increases reactive oxygen and nitrogen species, which causes oxidative damage. An increase in oxidative damage alters different cellular pathways and processes such as mitochondrial impairment, DNA damage response, cell cycle arrest, and inflammatory response, leading to pathogenesis and progression of neurodegenerative disease other neurological defects.

Neuroprotective Effects of Phytochemicals against Aluminum Chloride-Induced Alzheimer’s Disease through ApoE4/LRP1, Wnt3/β-Catenin/GSK3β, and TLR4/NLRP3 Pathways with Physical and Mental Activities in a Rat Model

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder that is associated with abnormal cognition. AD is aided in its initiation and progression by hereditary and environmental factors. Aluminum (Al) is a neurotoxic agent that causes oxidative stress, which is linked to AD progression. Additionally, Nrf2/HO-1, APOE4/LRP1, Wnt3/β-catenin, and TLR4/NLRP3 are the main signaling pathways involved in AD pathogenesis. Several phytochemicals are promising options in delaying AD evolution. Objectives: This study aimed at studying the neuroprotective effects of some phytochemicals as morin (MOR), thymol (TML), and thymoquinone (TMQ) on physical and mental activities (PhM) in Al chloride (AlCl₃)-induced AD rat model. Another objective was to determine the specificity of phytochemicals to AD signaling pathways using molecular docking. Methods: Eighty male Dawley rats were divided into eight groups. Each group received: saline (control group), AlCl₃, (ALAD), PhM, either alone or with a combination of MOR, TML, and/or TMQ for five weeks. Animals were then subjected to behavioral evaluation. Brain tissues were used for histopathological and biochemical analyses to determine the extent of neurodegeneration. The effect of phytochemicals on AlCl₃-induced oxidative stress and the main signaling pathways involved in AD progression were also investigated. Results: AlCl₃ caused a decline in spatial learning and memory, as well as histopathological changes in the brains of rats. Phytochemicals combined with PhM restored antioxidant activities, increased HO-1 and Nrf2 levels, blocked inflammasome activation, apoptosis, TLR4 expression, amyloide-β generation, and tau hyperphophorylation. They also brought ApoE4 and LRP1 levels back to normal and regulated Wnt3/β-catenin/GSK3β signaling pathway. Conclusions: The use of phytochemicals with PhM is a promising strategy for reducing AD by modulating Nrf2/HO-1, TLR4/NLRP3, APOE4/LRP1, and Wnt3/β-catenin/GSK-3β signaling pathways.

Modulation of High-Fat Diet-Induced Brain Oxidative Stress by Ferulate-Rich Germinated Brown Rice Ethyl Acetate Extract

The oxidative stress resulting from the production of reactive oxygen species plays a vital role in inflammatory processes and is associated with neurodegenerative changes. In view of the ability of germinated brown rice (GBR) to improve learning and memory, this present study aimed to investigate the mechanistic basis of GBR’s neuroprotection in a high-fat diet (HFD)-induced oxidative changes in adult Sprague–Dawley rats. Ferulate-rich GBR ethyl acetate extract (GBR-EA; 100 mg/kg and 200 mg/kg body weight) was supplemented orally for the last 3 months of 6 months HFD feeding during the study. GBR-EA supplementation was found to improve lipid profile and serum antioxidant status, when compared to the HFD group. Elevated mRNA expressions of SOD1, SOD2, SOD3, Catalase, and GPX were demonstrated in the frontal cortex and hippocampus of GBR-EA treated animals. The pro-inflammatory changes induced by HFD in the hippocampus were attenuated by GBR-EA through the downregulation of CRP and TNF- α and upregulation of PPAR-γ. GBR also reduced the hippocampal mRNA expression and enzyme level of acetylcholinesterase. In conclusion, this study proposed the possible transcriptomic regulation of antioxidant and inflammation in neurodegenerative processes resulting from high cholesterol consumption, with an emphasis on GBR’s potential to ameliorate such changes.

The Role of a Pathological Interaction between β-amyloid and Mitochondria in the Occurrence and Development of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases in existence. It is characterized by an impaired cognitive function that is due to a progressive loss of neurons in the brain. Extracellular β-amyloid (Aβ) plaques are the main pathological features of the disease. In addition to abnormal protein aggregation, increased mitochondrial fragmentation, altered expression of the genes involved in mitochondrial biogenesis, disruptions in the ER-mitochondria interaction, and mitophagy are observed. Reactive oxygen species are known to affect Aβ expression and aggregation. In turn, oligomeric and aggregated Aβ cause mitochondrial disorders. In this review, we summarize available knowledge about the pathological effects of Aβ on mitochondria and the potential molecular targets associated with proteinopathy and mitochondrial dysfunction for the pharmacological treatment of Alzheimer's disease.

The SELENOT mimetic PSELT promotes nerve regeneration by increasing axonal myelination in a facial nerve injury model in female rats

Peripheral nerve injury (PNI) is frequent and many patients suffer lifelong disabilities in severe cases. Although the peripheral nervous system is able to regenerate, its potential is limited. In this study, we tested in a nerve regeneration model in rat the potential beneficial effect of a short mimetic peptide, named PSELT, which derives from SELENOT, an essential thioredoxin-like selenoprotein endowed with neuroprotective and antioxidant activities. For this purpose, the right facial nerve of female Long-Evans rats was axotomized then bridged with a free femoral vein interposition graft. PSELT (1 μM) was injected into the vein immediately and 48 h after the injury, and the effects observed were compared to those found after an end-to-end suture used as a gold standard treatment. Whisking behavior, electrophysiological potential, and histological analyses were performed 3 months after injury to determine the effects of these treatments. These analyses revealed that PSELT-treated animals exhibit a better motor recovery in terms of protraction amplitude and velocity of vibrissae compared to control and end-sutured nerve animal groups. Moreover, administration of PSELT following injury enhanced muscle innervation, axonal elongation, and myelination of newly formed nerve fibers. Altogether, these results indicate that a PSELT-based treatment is sufficient to enhance facial nerve myelination and regeneration and could represent a new therapeutic tool to treat PNI.

Coffee Chlorogenic Acids Incorporation for Bioactivity Enhancement of Foods: A Review

The demand of foods with high antioxidant capacity have increased and research on these foods continues to grow. This review is focused on chlorogenic acids (CGAs) from green coffee, which is the most abundant source. The main CGA in coffee is 5-O-caffeoylquinic acid (5-CQA). Coffee extracts are currently the most widely used source to enhance the antioxidant activity of foods. Due to the solubility of CGAs, their extraction is mainly performed with organic solvents. CGAs have been associated with health benefits, such as antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory activity, and others that reduce the risk of cardiovascular diseases, type 2 diabetes, and Alzheimer's disease. However, the biological activities depend on the stability of CGAs, which are sensitive to pH, temperature, and light. The anti-inflammatory activity of 5-CQA is attributed to reducing the proinflammatory activity of cytokines. 5-CQA can negatively affect colon microbiota. An increase in anthocyanins and antioxidant activity was observed when CGAs extracts were added to different food matrices such as dairy products, coffee drinks, chocolate, and bakery products. The fortification of foods with coffee CGAs has the potential to improve the functionality of foods.

Antioxidant Quercetin 3-O-Glycosylated Plant Flavonols Contribute to Transthyretin Stabilization

Plants are rich in secondary metabolites, which are often useful as a relevant source of nutraceuticals. Quercetin (QUE) is a flavonol aglycone able to bind Transthyretin (TTR), a plasma protein that under pathological conditions can lose its native structure leading to fibrils formation and amyloid diseases onset. Here, the dual nature of five quercetin 3-O-glycosylated flavonol derivatives, isolated from different plant species, such as possible binders of TTR and antioxidants, was investigated. The crystal structure of 3-O-β-D-galactopyranoside in complex with TTR was solved, suggesting that not only quercetin but also its metabolites can contribute to stabilizing the TTR tetramer.

Inhibition of scopolamine-induced memory and mitochondrial impairment by betanin

Mitochondrial dysfunction and oxidative stress are identified to contribute to the mechanisms responsible for the pathogenesis of Alzheimer's disease (AD). Scopolamine (SCO) as a potent drug for inducing memory and learning impairment is associated with mitochondrial dysfunction and oxidative stress. In AD clinical trials molecules with antioxidant properties have shown modest benefit. Betanin as a multifunctional molecule with powerful antioxidative properties may be effective in the treatment of neurodegenerative. Hence, this study was designed to investigate the possible therapeutic effect of betanin against SCO-induced AD on Wistar rats. SCO (1 mg/kg) was administrated intraperitoneally to induce the AD in Wistar rats. The rats were treated with betanin doses (25 mg/kg and 50 mg/kg) intraperitoneally for 9 consecutive days. At the end of the 9th day, the animals were subjected to behavioral examination such as novel object recognition and passive avoidance tests and killed to study the mitochondrial and histological parameters. The results showed attenuation of SCO-induced memory and learning impairment by betanin at 50 mg/kg dose. Also, mitochondrial toxicity parameters such as mitochondrial membrane potential collapse, mitochondrial swelling, decreased activity of succinate dehydrogenase, and reactive oxygen species (ROS) production were reversed by betanin (50 mg/kg) compared to the SCO group. In addition, the ameliorative effect of betanin against SCO was demonstrated in histopathological results of hippocampus. The present investigation established that the betanin ameliorates the SCO-induced memory impairments, tissue injuries, and mitochondrial dysfunction by reducing mitochondrial ROS, which may be due to the potent antioxidant action of betanin.

Medicinal Plants for Anti-neurodegenerative diseases in West Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Neurodegenerative diseases are neuronal diseases that affect the brain components by degenerating the structure and function of the central or peripheral nervous system progressively. It is a leading cause of death and affects huge amount of people worldwide. Plant-based medicines have been utilised in the therapies for many illnesses that have defied western treatments, including neurodegenerative diseases.

AIM OF THIS REVIEW

This review presents an overview of the major neurodegenerative diseases and reported prominent medicinal plants used in managing those diseases in West Africa.

METHODS

Scientific articles regarding medicinal plants and their usefulness in managing neurodegenerative diseases in West Africa were pooled from different scientific databases. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses to filter articles based on their relevance. Pharmacological activity, plant parts used, experimental models, and some isolated chemical compounds of those plants were summarised.

RESULTS

In the West Africa region, Fabaceae (19%) and Solanaceae (13%) have the highest representation of plant families used to treat neurological diseases, while Apocynaceae, Asteraceae, Euphorbiaceae have also been utilised. Flavonoids, alkaloids, phenolic compounds, terpenoids, coumarins present in those plants and their derivatives are reported to possess neuro-protective effects. Biochemical enzymes correlating to antioxidants, anti-inflammatory effects are the potential targets against neurodegenerative diseases.

CONCLUSION

Medicinal plants for anti-neurodegenerative diseases in West Africa have been documented with their neuropharmacological activities. Plant families such as Fabaceae, Solanaceae, Apocynaceae, Asteraceae, and Euphorbiaceae could be a major natural source for discovery of anti-neurodegenerative drugs, thus the metabolites from them should be given priority for neurological research. This review will provide clues for further investigations on the screening and development of anti-neurodegenerative natural products from West African medicinal plants.

Antioxidant Therapy in Oxidative Stress-Induced Neurodegenerative Diseases: Role of Nanoparticle-Based Drug Delivery Systems in Clinical Translation

Free radicals are formed as a part of normal metabolic activities but are neutralized by the endogenous antioxidants present in cells/tissue, thus maintaining the redox balance. This redox balance is disrupted in certain neuropathophysiological conditions, causing oxidative stress, which is implicated in several progressive neurodegenerative diseases. Following neuronal injury, secondary injury progression is also caused by excessive production of free radicals. Highly reactive free radicals, mainly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), damage the cell membrane, proteins, and DNA, which triggers a self-propagating inflammatory cascade of degenerative events. Dysfunctional mitochondria under oxidative stress conditions are considered a key mediator in progressive neurodegeneration. Exogenous delivery of antioxidants holds promise to alleviate oxidative stress to regain the redox balance. In this regard, natural and synthetic antioxidants have been evaluated. Despite promising results in preclinical studies, clinical translation of antioxidants as a therapy to treat neurodegenerative diseases remains elusive. The issues could be their low bioavailability, instability, limited transport to the target tissue, and/or poor antioxidant capacity, requiring repeated and high dosing, which cannot be administered to humans because of dose-limiting toxicity. Our laboratory is investigating nanoparticle-mediated delivery of antioxidant enzymes to address some of the above issues. Apart from being endogenous, the main advantage of antioxidant enzymes is their catalytic mechanism of action; hence, they are significantly more effective at lower doses in detoxifying the deleterious effects of free radicals than nonenzymatic antioxidants. This review provides a comprehensive analysis of the potential of antioxidant therapy, challenges in their clinical translation, and the role nanoparticles/drug delivery systems could play in addressing these challenges.

Antioxidants in Alzheimer's Disease: Current Therapeutic Significance and Future Prospects

Alzheimer's disease (AD) rate is accelerating with the increasing aging of the world's population. The World Health Organization (WHO) stated AD as a global health priority. According to the WHO report, around 82 million people in 2030 and 152 million in 2050 will develop dementia (AD contributes 60% to 70% of cases), considering the current scenario. AD is the most common neurodegenerative disease, intensifying impairments in cognition, behavior, and memory. Histopathological AD variations include extracellular senile plaques' formation, tangling of intracellular neurofibrils, and synaptic and neuronal loss in the brain. Multiple evidence directly indicates that oxidative stress participates in an early phase of AD before cytopathology. Moreover, oxidative stress is induced by almost all misfolded protein lumps like α-synuclein, amyloid-β, and others. Oxidative stress plays a crucial role in activating and causing various cell signaling pathways that result in lesion formations of toxic substances, which foster the development of the disease. Antioxidants are widely preferred to combat oxidative stress, and those derived from natural sources, which are often incorporated into dietary habits, can play an important role in delaying the onset as well as reducing the progression of AD. However, this approach has not been extensively explored yet. Moreover, there has been growing evidence that a combination of antioxidants in conjugation with a nutrient-rich diet might be more effective in tackling AD pathogenesis. Thus, considering the above-stated fact, this comprehensive review aims to elaborate the basics of AD and antioxidants, including the vitality of antioxidants in AD. Moreover, this review may help researchers to develop effectively and potentially improved antioxidant therapeutic strategies for this disease as it also deals with the clinical trials in the stated field.

Different Fruit-Specific Promoters Drive AtMYB12 Expression to Improve Phenylpropanoid Accumulation in Tomato

Tomato is an economically crucial vegetable/fruit crop globally. Tomato is rich in nutrition and plays an essential role in a healthy human diet. Phenylpropanoid, a critical compound in tomatoes, reduces common degenerative and chronic diseases risk caused by oxidative stress. As an MYB transcription factor, ATMYB12 can increase phenylpropanoid content by activating phenylpropanoid synthesis related genes, such as PAL, C4H, 4CL, CHS. However, the heterologous expression of AtMYB12 in tomatoes can be altered through transgenic technologies, such as unstable expression vectors and promoters with different efficiency. In the current study, the efficiency of other fruit-specific promoters, namely E8S, 2A12, E4, and PG, were compared and screened, and we determined that the expression efficiency of AtMYB12 was driven by the E8S promoter was the highest. As a result, the expression of phenylpropanoid synthesis related genes was regulated by AtMYB12, and the phenylpropanoid accumulation in transgenic tomato fruits increased 16 times. Additionally, the total antioxidant capacity of fruits was measured through Trolox equivalent antioxidant capacity (TEAC) assay, which was increased by 2.4 times in E8S transgenic lines. TEAC was positively correlated with phenylpropanoid content. Since phenylpropanoid plays a crucial role in the human diet, expressing AtMYB12 with stable and effective fruit-specific promoter E8S could improve tomato’s phenylpropanoid and nutrition content and quality. Our results can provide genetic resources for the subsequent improvement of tomato varieties and quality, which is significant for human health.

Herbal Plethora for Management of Neurodegenerative Disorders: An Invigorating Outlook

Objective:

Oxidative stress, proteasomal impairment, mitochondrial dysfunction, and accumulation of abnormal protein aggregates have shovelled a major section of the senior population towards neurodegenerative disorders. Although age, genetic and environmental factors are thought to play a significant role, drug abuse is considered to be a potent trigger in Parkinsonism among the young generation. The present study is a critical examination of herbal resources for attenuation of neurodegeneration.

Materials and Methods:

The following electronic databases have been used to search for literature: MEDLINE, Scopus, PubMed, and EMBASE

Results :

Paying heed to the prevalence of neurodegenerative disorders such as Alzheimer’s and Parkinson’s, the current review encompasses the pathogenesis of neurodegeneration at the cellular level and possible prospects to overcome the challenge sailing through the ocean of herbal boon. The United States’s Alzheimer’s Association states that deaths attributable to heart disease in the country fell by 11% between 2000 and 2015, while deaths from neurodegenerative diseases increased by a staggering 123% making it, the world’s sixth-leading cause of death. The irreversible pathological damage amounts to cognitive loss, dementia, Amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD) Alzheimer’s disease (AD). Various herbal drugs like Brahmi, Shankhpushpi, and Amla are reported to be rich in phytoconstituents like flavonoids, glycosides, alkaloids, fatty acids, sterols, tannins, saponins, and terpenes that have remarkable antioxidant potential and could be explored for the same to prevent neuronal necrosis.

Conclusion:

It is also believed that herbal medicines are more effective and less toxic than synthetic drugs.

Neuroprotective Properties of Quinone Reductase 2 Inhibitor M-11, a 2-Mercaptobenzimidazole Derivative

The ability of NQO2 to increase the production of free radicals under enhanced generation of quinone derivatives of catecholamines is considered to be a component of neurodegenerative disease pathogenesis. The present study aimed to investigate the neuroprotective mechanisms of original NQO2 inhibitor M-11 (2-[2-(3-oxomorpholin-4-il)-ethylthio]-5-ethoxybenzimidazole hydrochloride) in a cellular damage model using NQO2 endogenous substrate adrenochrome (125 µM) and co-substrate BNAH (100 µM). The effects of M-11 (10-100 µM) on the reactive oxygen species (ROS) generation, apoptosis and lesion of nuclear DNA were evaluated using flow cytometry and single-cell gel electrophoresis assay (comet assay). Results were compared with S29434, the reference inhibitor of NQO2. It was found that treatment of HT-22 cells with M-11 results in a decline of ROS production triggered by incubation of cells with NQO2 substrate and co-substrate. Pre-incubation of HT-22 cells with compounds M-11 or S29434 results in a decrease of DNA damage and late apoptotic cell percentage reduction. The obtained results provide a rationale for further development of the M-11 compound as a potential neuroprotective agent.

Delineation of Neuroprotective Effects and Possible Benefits of AntioxidantsTherapy for the Treatment of Alzheimer's Diseases by Targeting Mitochondrial-Derived Reactive Oxygen Species: Bench to Bedside

Alzheimer's disease (AD) is considered the sixth leading cause of death in elderly patients and is characterized by progressive neuronal degeneration and impairment in memory, language, etc. AD is characterized by the deposition of senile plaque, accumulation of fibrils, and neurofibrillary tangles (NFTs) which are responsible for neuronal degeneration. Amyloid-β (Aβ) plays a key role in the process of neuronal degeneration in the case of AD. It has been reported that Aβ is responsible for the production of reactive oxygen species (ROS), depletion of endogenous antioxidants, increase in intracellular Ca²⁺ which further increases mitochondria dysfunctions, oxidative stress, release of pro-apoptotic factors, neuronal apoptosis, etc. Thus, oxidative stress plays a key role in the pathogenesis of AD. Antioxidants are compounds that have the ability to counteract the oxidative damage conferred by ROS. Therefore, the antioxidant therapy may provide benefits and halt the progress of AD to advance stages by counteracting neuronal degeneration. However, despite the beneficial effects imposed by the antioxidants, the findings from the clinical studies suggested inconsistent results which might be due to poor study design, selection of the wrong antioxidant, inability of the molecule to cross the blood-brain barrier (BBB), treatment in the advanced state of disease, etc. The present review insights into the neuroprotective effects and limitations of the antioxidant therapy for the treatment of AD by targeting mitochondrial-derived ROS. This particular article will certainly help the researchers to search new avenues for the treatment of AD by utilizing mitochondrial-derived ROS-targeted antioxidant therapies.

Ephedra sinica mitigates hepatic oxidative stress and inflammation via suppressing the TLR4/MyD88/NF-κB pathway in fipronil-treated rats

Ephedra sinica (ES) is a promising medicinal plant with a wide range of pharmacological aspects, including antioxidant and anti-inflammatory properties. Fipronil (FN) is a popularly used systemic insecticide in agriculture and veterinary applications. FN exposure can result in a variety of negative health consequences. The study aimed to explore the prophylactic effects of Ephedra sinica extract (ESE) against hepatotoxicity in FN-treated rats by following the TLR4/ MyD88/ NF-κB pathway. ESE was tested for polyphenolic and antioxidant activity. Forty rats were separated into four groups and given orally by FN (10 mg/kg B.W.) and/or ESE (150 mg/kg B.W.). Blood and tissue samples were collected at the end of the experiment and prepared for pathophysiological, gene expression, and pathological analysis. ESE showed strong antioxidant activity, as well as reduced levels of hepatic MDA and oxidative stress markers (H₂O₂, NO). Hepatic SOD and CAT activities were increased even further. Furthermore, in FN-treated rats, ESE improved liver functions (ALT, AST, ALP, and LDH) and recovered the lipid profile (Cho, TriG, HDL, and LDL). Moreover, by inhibiting TLR4/ MyD88/ NF-κB induction, ESE alleviated hepatic pathological changes and decreased FN-induced elevations of TNF-α, IL-6, and IL-1β mRNA/protein levels. These findings suggested that ESE mitigated FN-induced hepatotoxicity via combating oxidative stress and relieving inflammation.

From obesity to Alzheimer's disease through insulin resistance

Alzheimer's disease is one of the most frequent forms of dementia. It is a progressive neurodegenerative disease, characterized by presence of amyloid plaques and neurofibrillary tangles in the brain. Obesity is regarded as abnormal fat accumulation with deleterious impact on human health. There is full scientific evidence that obesity and the metabolic comorbidities (e.g., insulin resistance, hyperglycaemia, and type 2 diabetes) are related to Alzheimer's disease and likely in the causative pathway. Numerous studies have identified several overlapping neurodegenerative mechanisms, including oxidative stress, mitochondrial dysfunction, and inflammation. In this review, we present how obesity and the associated lipotoxicity as well as chronic inflammation initiate a state of insulin resistance that in turn, may have a role in causing the characteristic cerebral alterations of AD. In particular, we focus on the molecular mechanisms linking the obesity-induced impairment in insulin signalling to the upregulation of Aβ aggregation, tau hyper-phosphorylation, inflammation, oxidative stress and mitochondrial dysfunction.

Thunbergia laurifolia Leaf Extract Inhibits Glutamate-Induced Neurotoxicity and Cell Death through Mitophagy Signaling

Oxidative stress plays a crucial role in neurodegeneration. Therefore, reducing oxidative stress in the brain is an important strategy to prevent neurodegenerative disorders. Thunbergia laurifolia (Rang-jued) is well known as an herbal tea in Thailand. Here, we aimed to determine the protective effects of T. laurifolia leaf extract (TLE) on glutamate-induced oxidative stress toxicity and mitophagy-mediated cell death in mouse hippocampal cells (HT-22). Our results reveal that TLE possesses a high level of bioactive antioxidants by LC–MS technique. We found that the pre-treatment of cells with TLE prevented glutamate-induced neuronal death in a concentration-dependent manner. TLE reduced the intracellular ROS and maintained the mitochondrial membrane potential caused by glutamate. Moreover, TLE upregulated the gene expression of antioxidant enzymes (SOD1, SOD2, CAT, and GPx). Interestingly, glutamate also induced the activation of the mitophagy process. However, TLE could reverse this activity by inhibiting autophagic protein (LC3B-II/LC3B-I) activation and increasing a specific mitochondrial protein (TOM20). Our results suggest that excessive glutamate can cause neuronal death through mitophagy-mediated cell death signaling in HT-22 cells. Our findings indicate that TLE protects cells from neuronal death by stimulating the endogenous antioxidant enzymes and inhibiting glutamate-induced oxidative toxicity via the mitophagy–autophagy pathway. TLE might have potential as an alternative or therapeutic approach in neurodegenerative diseases.

Protective Effects of Inosine on Memory Consolidation in a Rat Model of Scopolamine-Induced Cognitive Impairment: Involvement of Cholinergic Signaling, Redox Status, and Ion Pump Activities

This study investigated the effects of inosine on memory acquisition and consolidation, cholinesterases activities, redox status and Na⁺, K⁺-ATPase activity in a rat model of scopolamine-induced cognitive impairment. Adult male rats were divided into four groups: control (saline), scopolamine (1 mg/kg), scopolamine plus inosine (50 mg/kg), and scopolamine plus inosine (100 mg/kg). Inosine was pre-administered for 7 days, intraperitoneally. On day 8, scopolamine was administered pre (memory acquisition protocol) or post training (memory consolidation protocol) on inhibitory avoidance tasks. The animals were subjected to the step-down inhibitory avoidance task 24 hours after the training. Scopolamine induced impairment in the acquisition and consolidation phases; however, inosine was able to prevent only the impairment in memory consolidation. Also, scopolamine increased the activity of acetylcholinesterase and reduced the activity of Na⁺, K⁺-ATPase and the treatment with inosine protected against these alterations in consolidation protocol. In the animals treated with scopolamine, inosine improved the redox status by reducing the levels of reactive oxygen species and thiobarbituric acid reactive substances and restoring the activity of the antioxidant enzymes, superoxide dismutase and catalase. Our findings suggest that inosine may offer protection against scopolamine-induced memory consolidation impairment by modulating brain redox status, cholinergic signaling and ion pump activity. This compound may provide an interesting approach in pharmacotherapy and as a prophylactic against neurodegenerative mechanisms involved in Alzheimer's disease.

Free Radicals and Actinobacteria as a Misexplored Goldmine of Antioxidant Compounds

Free radicals are highly reactive unstable molecules, which can be synthesized in different ways, considered harmful and threatening to humans; these chemical species have free traffic throughout the human body, interacting with biological molecules and human body organ tissues. The interaction between free radicals and biological molecules is the main factor for disease development or pre-existing disease symptoms aggravation. Antioxidants are chemical compounds able to donate electric charge to stabilize molecules such as free radicals. Recent studies have proved the benefits of antioxidants intake in health improvement. In this way, the search for natural sources of antioxidants has become an ascending trend. In this field, the microbial sources are considered poorly explored compared to the numerous amount of other compounds obtained from them, especially from Actinobacteria. The searched literature about Actinobacteria highlights an important capacity of producing natural antioxidants; however, there is a lack of in vivo studies of these isolated compounds. In this review, we gathered information that supports our point of view that Actinobacteria is a truly renewable and superficially explored source of natural antioxidants. Furthermore, our purpose is also to point this limitation and stimulate more researches in this area.

Multifunctional Redox Modulators Protect Auditory, Visual, and Cognitive Function

Significance: Oxidative stress contributes to vision, hearing and neurodegenerative disorders. Currently, no treatments prevent these disorders; therefore, there is an urgent need for redox modulators that can prevent these disorders. Recent Advances: Oxidative stress is associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species, metal dyshomeostasis, and mitochondrial dysfunction. Here, we discuss the role that oxidative stress and metal dyshomeostasis play in hearing loss, visual impairments, and neurodegeneration and discuss the benefits of a new class of multifunctional redox modulators (MFRMs) that suppress sensory and neural degeneration. MFRMs not only reduce free radicals but also independently bind transition metals associated with the generation of hydroxyl radicals. The MFRMs redistribute zinc from neurotoxic amyloid beta zinc (Aβ:Zn) complexes to the cytoplasm, facilitating the degradation of Aβ plaques by matrix metalloprotease-2 (MMP-2). Although MFRMs bind copper (Cu1+, Cu2+), iron (Fe2+, Fe3+), zinc (Zn2+), and manganese (Mn2+), they do not deplete free cytoplasmic Zn+2 and they protect mitochondria from Mn+2-induced dysfunction. Oral administration of MFRMs reduce ROS-induced cataracts, protect the retina from light-induced degeneration, reduce neurotoxic Aβ:Zn plaque formation, and protect auditory hair cells from noise-induced hearing loss. Critical Issues: Regulation of redox balance is essential for clinical efficacy in maintaining sensory functions. Future Directions: Future use of these MFRMs requires additional pharmacokinetic, pharmacodynamics, and toxicological data to bring them into widespread clinical use. Additional animal studies are also needed to determine whether MFRMs can prevent neurodegeneration, dementia, and other forms of vision and hearing loss.

Halophytes as source of bioactive phenolic compounds and their potential applications

Halophytes are salt-tolerant plants that inhabit environments in which they are exposed to extreme stress, wherefore they exhibit conserved and divergent metabolic responses different from those of conventional plants. Thus, the synthesis and accumulation of metabolites, especially of those oxidative stress-related such as phenolic compounds, should be investigated. The potential of halophytes as a source of phenolics and their prospective industrial applications are evaluated based on a comprehensive review of the scientific literature on the phenolic compounds of more than forty halophytes and their biological activities. Additionally, an overview of the analytical methodologies adopted for phenolics determination in halophytes is provided. Finally, the prospective uses and beneficial effects of the phenolic preparations from these plants are discussed. Halophytes are complex matrices, exhibiting a wide variety of phenolics in their composition, wherefore the results can be greatly affected depending on the organ plant under analysis and the extraction methodology, especially the extraction solvent used. High-performance liquid chromatography, coupled with diode array detection (HPLC-DAD) or mass spectrometry (HPLC-MS), are the most used technique. Halophytes biosynthesize phenolics in concentrations that justify the remarkable antioxidant and antimicrobial activities shown, making them ideal sources of bioactive molecules to be employed in a multitude of sectors.

Berberine-Albumin Nanoparticles: Preparation, Thermodynamic Study and Evaluation Their Protective Effects Against Oxidative Stress in Primary Neuronal Cells as a Model of Alzheimer's Disease

Berberine has shown an outstanding antioxidant activity, however the low bioavailability limits its applications in pharmaceutical platforms. Therefore, in this paper, after fabrication of the berberine-HSA nanoparticles by desolvation method, they were well characterized by TEM, SEM, DLS, and FTIR techniques. Afterwards the interaction of HSA and the berberine was evaluated by molecular docking analysis. Finally, the antioxidant activity of the berberine-HSA nanoparticles against H₂O₂-induced oxidative stress in cultured neurons as a model of AD was evaluated by cellular assays. The results showed that the prepared berberine-HSA nanoparticles have a spherical-shaped morphology with a size of around 100 nm and zeta potential value of -31.84 mV. The solubility value of nanoparticles was calculated to be 40.27%, with a berberine loading of 19.37%, berberine entrapment efficiency of 70.34%, and nanoparticles yield of 88.91%. Also, it was shown that the berberine is not significantly released from HSA nanoparticles within 24 hours. Afterwards, molecular docking investigation revealed that berberine spontaneously interacts with HSA through electrostatic interaction. Finally, cellular assays disclosed that the pretreatment of neuronal cultures with berberine-HSA nanoparticles decreased the H₂O₂-stimulated cytotoxicity and relevant morphological changes and enhanced the CAT activity. In conclusion, it can be indicated that the nanoformulation of the berberine can be used as a promising platform for inhibition of oxidative damage-induced Alzheimer's disease (AD).

Bridging Cyanobacteria to Neurodegenerative Diseases: A New Potential Source of Bioactive Compounds against Alzheimer's Disease

Neurodegenerative diseases (NDs) represent a drawback in society given the ageing population. Dementias are the most prevalent NDs, with Alzheimer’s disease (AD) representing around 70% of all cases. The current pharmaceuticals for AD are symptomatic and with no effects on the progression of the disease. Thus, research on molecules with therapeutic relevance has become a major focus for the scientific community. Cyanobacteria are a group of photosynthetic prokaryotes rich in biomolecules with confirmed activity in pathologies such as cancer, and with feasible potential in NDs such as AD. In this review, we aimed to compile the research works focused in the anti-AD potential of cyanobacteria, namely regarding the inhibition of the enzyme β-secretase (BACE1) as a fundamental enzyme in the generation of β-amyloid (Aβ), the inhibition of the enzyme acetylcholinesterase (AChE) lead to an increase in the availability of the neurotransmitter acetylcholine in the synaptic cleft and the antioxidant and anti-inflammatory effects, as phenomena associated with neurodegeneration mechanisms.

Whether short peptides are good candidates for future neuroprotective therapeutics?

Neurodegenerative diseases are a broad group of largely debilitating, and ultimately terminal conditions resulting in progressive degeneration of different brain regions. The observed damages are associated with cell death, structural and functional deficits of neurons, or demyelination. The concept of neuroprotection concerns the administration of the agent, which should reverse some of the damage or prevent further adverse changes. A growing body of evidence suggested that among many classes of compounds considered as neuroprotective agents, peptides derived from natural materials or their synthetic analogs are good candidates. They presented a broad spectrum of activities and abilities to act through diverse mechanisms of action. Biologically active peptides have many properties, including antioxidant, antimicrobial, antiinflammatory, and immunomodulatory effects. Peptides with pro-survival and neuroprotective activities, associated with inhibition of oxidative stress, apoptosis, inflammation and are able to improve cell viability or mitochondrial functions, are also promising molecules of particular interest to the pharmaceutical industries. Peptide multiple activities open the way for broad application potential as therapeutic agents or ingredients of health-promoting functional foods. Significantly, synthetic peptides can be remodeled in numerous ways to have desired features, such as increased solubility or biological stability, as well as selectivity towards a specific receptor, and finally better membrane penetration. This review summarized the most common features of major neurodegenerative disorders, their causes, consequences, and reported new neuroprotective drug development approaches. The author focused on the unique perspectives in neuroprotection and provided a concise survey of short peptides proposed as novel therapeutic agents against various neurodegenerative diseases.

Dysbiosis and Alzheimer's Disease: A Role for Chronic Stress?

Alzheimer’s disease (AD) is an incurable, neuropsychiatric, pathological condition that deteriorates the worth of geriatric lives. AD is characterized by aggregated senile amyloid plaques, neurofibrillary tangles, neuronal loss, gliosis, oxidative stress, neurotransmitter dysfunction, and bioenergetic deficits. The changes in GIT composition and harmony have been recognized as a decisive and interesting player in neuronal pathologies including AD. Microbiota control and influence the oxidoreductase status, inflammation, immune system, and the endocrine system through which it may have an impact on the cognitive domain. The altered and malfunctioned state of microbiota is associated with minor infections to complicated illnesses that include psychosis and neurodegeneration, and several studies show that microbiota regulates neuronal plasticity and neuronal development. The altered state of microbiota (dysbiosis) may affect behavior, stress response, and cognitive functions. Chronic stress-mediated pathological progression also has a well-defined role that intermingles at various physiological levels and directly impacts the pathological advancement of AD. Chronic stress-modulated alterations affect the well-established pathological markers of AD but also affect the gut–brain axis through the mediation of various downstream signaling mechanisms that modulate the microbial commensals of GIT. The extensive literature reports that chronic stressors affect the composition, metabolic activities, and physiological role of microbiota in various capacities. The present manuscript aims to elucidate mechanistic pathways through which stress induces dysbiosis, which in turn escalates the neuropathological cascade of AD. The stress–dysbiosis axis appears a feasible zone of work in the direction of treatment of AD.

The Antihypertensive Effects and Potential Molecular Mechanism of Microalgal Angiotensin I-Converting Enzyme Inhibitor-Like Peptides: A Mini Review

Hypertension causes many deaths worldwide and has shown an increasing trend as a severe non-communicable disease. Conventional antihypertensive drugs inevitably cause side effects, and great efforts have been made to exploit healthier and more-available substitutes. Microalgae have shown great potential in this regard and have been applied in the food and pharmaceutical industries. Some compounds in microalgae have been proven to have antihypertensive effects. Among these natural compounds, peptides from microalgae are promising angiotensin-converting enzyme (ACE) inhibitors because an increasing number of peptides show hypertensive effects and ACE inhibitory-like activity. In addition to acting as ACE inhibitors for the treatment of hypertension, these peptides have other probiotic properties, such as antioxidant and anti-inflammatory properties, that are important for the prevention and treatment of hypertension. Numerous studies have revealed the important bioactivities of ACE inhibitors and their mechanisms. This review discusses the antihypertensive effects, structure-activity relationships, molecular docking studies, interaction mechanisms, and other probiotic properties of microalgal ACE inhibitory peptides according to the current research related to microalgae as potential antihypertensive drugs. Possible research directions are proposed. This review contributes to a more comprehensive understanding of microalgal antihypertensive peptides.

Avoid the trap: Targeting PARP1 beyond human malignancy

PARP1 is a poly(ADP-ribose) polymerase (PARP) enzyme that plays a critical role in regulating DNA damage response. The main enzymatic function of PARP1 is to catalyze a protein post-translational modification known as poly(ADP-ribosyl)ation (PARylation). Human cancers with homologous recombination deficiency are highly sensitive to PARP1 inhibitors. PARP1 is aberrantly activated in many non-oncological diseases, leading to the excessive NAD⁺ depletion and PAR formation, thus causing cell death and tissue damage. PARP1 deletion offers a profound protective effect in the relevant animal models. However, many of the current PARP1 inhibitors also induce PARP1 trapping, which drives subsequent DNA damage, innate immune response and cytotoxicity. This minireview provides an overview of the basic biology of PARP1 trapping, and its implications in disease. Furthermore, we also discuss the recent development of PARP1 PROTAC compounds, and their utility as "non-trapping" PARP1 degraders for the potential amelioration of non-oncological diseases driven by aberrant PARP1 activation.

Strawberry (Fragaria ananassa duch.) Alba extract attenuates DNA damage in lymphocytes of patients with Alzheimer's disease

Increased levels of oxidative stress and oxidative DNA damage are common features in the pathology of Alzheimer's disease (AD) found in neurons and peripheral cells like peripheral blood lymphocytes (PBL). Natural products such as strawberry cultivar Alba are an important source of bioactive nutrients that could help in lowering both the oxidative stress and DNA damage levels. The objective was to estimate the effects of Alba extract on DNA damage in peripheral blood lymphocytes of sporadic AD (aged 60-84 years) patients, and healthy elderly (aged 69-83 years) and young (aged 21-30 years) individuals in in vitro conditions. Comet assay was used as a sensitive technique for the evaluation of PBL DNA damage levels. Reduction of basal DNA damage level in PBL was shown in the young group after the incubation with Alba extract ranging from 25 to 200 μg/ml, with 100 μg/ml being the most effective concentration. Selected Alba extract of 100 μg/ml was further used for PBL treatment of AD and healthy elderly age matched group, displaying potential to significantly attenuate DNA damage levels in both groups (p < .05). Alba extract displayed biological activity against oxidative DNA damage, suggesting that its functional ingredients may have beneficial health effects. PRACTICAL APPLICATIONS: The data obtained in this preliminary study displayed that strawberry Alba extract is efficient against DNA damage induced by endogenous and exogenous oxidative stress in peripheral blood lymphocytes of Alzheimer`s disease in vitro. An active area of future research of Alba cultivar should be to determine the trials in in vivo systems. Our findings also suggest that Alba cultivar's functional ingredients potentially may have beneficial health effects in AD.

Inhibition of Lysozyme Amyloid Fibrillation by Silybin Diastereoisomers: The Effects of Stereochemistry

Silybin is a flavonoid lignin compound consisting of two diastereomers with nearly equal molar ratios. It has been reported that silybin can effectively inhibit the aggregation of amyloid protein, but the difference between the two silybin diastereomers has been rarely studied. In this work, the inhibitory ability of silybin to hen egg-white lysozyme (HEWL) was demonstrated, and the difference of kinetic parameters of two diastereomers was analyzed. Fluorescence quenching titration was utilized to analyze the binding differences to native HEWL between the diastereomers, and transmission electron microscopy (TEM) was utilized to analyze the characteristics of the surface of various samples. The differences between hydrophobicity and the secondary structure among several HEWL samples were measured by the 8-anilino-1-naphthalene sulfonic (ANS) acid fluorescence probe, Raman spectra, and far-UV circular dichroism. Moreover, the differences in the binding energy of these two diastereomers with HEWL were analyzed by molecular docking. Also, we have investigated the effect of silybin diastereomers on HEWL fibril-induced cytotoxicity in SH-SY5Y cells. Results show that silybin has a certain inhibitory effect on the HEWL fibrillogenesis process, while silybin B (SB) has a more significant inhibitory effect than silybin A (SA), especially at high concentrations. This work provides some insights into the screening of amyloid inhibitors from complicated natural products and indicates that SB has the prospect of further development as an amyloid inhibitor.

Intracellular Sources of ROS/H2O2 in Health and Neurodegeneration: Spotlight on Endoplasmic Reticulum

Reactive oxygen species (ROS) are produced continuously throughout the cell as products of various redox reactions. Yet these products function as important signal messengers, acting through oxidation of specific target factors. Whilst excess ROS production has the potential to induce oxidative stress, physiological roles of ROS are supported by a spatiotemporal equilibrium between ROS producers and scavengers such as antioxidative enzymes. In the endoplasmic reticulum (ER), hydrogen peroxide (H2O2), a non-radical ROS, is produced through the process of oxidative folding. Utilisation and dysregulation of H2O2, in particular that generated in the ER, affects not only cellular homeostasis but also the longevity of organisms. ROS dysregulation has been implicated in various pathologies including dementia and other neurodegenerative diseases, sanctioning a field of research that strives to better understand cell-intrinsic ROS production. Here we review the organelle-specific ROS-generating and consuming pathways, providing evidence that the ER is a major contributing source of potentially pathologic ROS.

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

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