Neuroprotective effect of sulforaphane in 6-hydroxydopamine-lesioned mouse model of Parkinson's disease

Sulforaphane and Brain Health: From Pathways of Action to Effects on Specific Disorders

The brain accounts for about 2% of the body's weight, but it consumes about 20% of the body's energy at rest, primarily derived from ATP produced in mitochondria. The brain thus has a high mitochondrial density in its neurons because of its extensive energy demands for maintaining ion gradients, neurotransmission, and synaptic activity. The brain is also extremely susceptible to damage and dysregulation caused by inflammation (neuroinflammation) and oxidative stress. Many systemic challenges to the brain can be mitigated by the phytochemical sulforaphane (SF), which is particularly important in supporting mitochondrial function. SF or its biogenic precursor glucoraphanin, from broccoli seeds or sprouts, can confer neuroprotective and cognitive benefits via diverse physiological and biochemical mechanisms. SF is able to cross the blood-brain barrier as well as to protect it, and it mitigates the consequences of destructive neuroinflammation. It also protects against the neurotoxic effects of environmental pollutants, combats the tissue and cell damage wrought by advanced glycation end products (detoxication), and supports healthy glucose metabolism. These effects are applicable to individuals of all ages, from the developing brains in periconception and infancy, to cognitively, developmentally, and traumatically challenged brains, to those in later life as well as those who are suffering with multiple chronic conditions including Parkinson's and Alzheimer's diseases.

Molecular mechanisms of GDNF/GFRA1/RET and PI3K/AKT/ERK signaling interplay in neuroprotection: Therapeutic strategies for treating neurological disorders

Neurological disorders, marked by progressive neuronal degeneration, impair essential cognitive functions like memory and motor coordination… This manuscript explores the significant roles of glial cell line-derived neurotrophic factor (GDNF), its co-receptors (GFRA1), and the receptor tyrosine kinase (RET) in mediating neuronal survival and function in various neurodegenerative conditions. The interplay between pivotal signaling pathways-PI3K/AKT and ERK1/2-facilitated by GDNF/GFRA1/RET, is emphasized for its neuroprotective effects. Dysregulation of these pathways is implicated in neurodegenerative and neuropsychiatric processes, with overactivation of GSK3β contributing to neuronal damage and apoptosis. Experimental evidence supports that activation of the RET receptor by GDNF enhances AKT signaling, promoting cell survival by inhibiting apoptotic pathways-therapeutic strategies incorporating GDNF delivery and RET activation present promising neuronal protection and regeneration options. Furthermore, inhibition of GSK3β demonstrates potential in ameliorating tau-related pathologies, while small molecule RET agonists may enhance therapeutic efficacy. This review explores the knowledge of GDNF/GFRA1/RET and PI3K/AKT/ERK1/2 associated signaling cascades, underscoring their significance in neuroprotection and therapeutic targeting to combat neurodegenerative diseases. Emerging approaches such as gene therapy and small-molecule RET agonists may offer novel avenues for treatment, although challenges like targeted delivery across the blood-brain barrier remain pertinent.

Phytochemical strategies in glioblastoma therapy: Mechanisms, efficacy, and future perspectives

Glioblastoma (GBM) is foremost the most aggressive primary brain tumor, presenting extensive therapeutic challenges due to its high invasiveness, genetic complexity, and resistance to established treatments. Despite substantial advances in surgical and chemotherapeutic interventions, the median survival rate for patients is only 14.6 months, and the prognosis remains poor. This review focuses on the molecular hallmarks of GBM, including the activation of the PI3K/Akt pathway, genomic instability, and the deregulation of epidermal growth factor receptor (EGFR), all of which contribute to the tumor's aggressive behavior. Current therapies, such as Temozolomide and Bevacizumab, have limitations, highlighting the need for novel treatment strategies. Phytochemicals, bioactive compounds found in plants, have emerged as potential therapeutic agents by targeting multiple cellular pathways involved in GBM progression. This review provides an overview of key phytochemicals, including quercetin, curcumin, apigenin, and resveratrol. These compounds have shown promise in preclinical studies, with their anti-invasive, anti- angiogenic, pro-apoptotic, and anti-proliferative properties positioning them as strong candidates for GBM therapy. While phytochemicals offer a promising avenue for GBM treatment, further research is required to fully understand their mechanisms of action and to evaluate their efficiency in clinical settings. Developing multi-targeted, safer, and cost-effective anti-GBM therapies could significantly improve patient outcomes.

Model organisms for investigating the functional involvement of NRF2 in non-communicable diseases

Non-communicable chronic diseases (NCDs) are most commonly characterized by age-related loss of homeostasis and/or by cumulative exposures to environmental factors, which lead to low-grade sustained generation of reactive oxygen species (ROS), chronic inflammation and metabolic imbalance. Nuclear factor erythroid 2-like 2 (NRF2) is a basic leucine-zipper transcription factor that regulates the cellular redox homeostasis. NRF2 controls the expression of more than 250 human genes that share in their regulatory regions a cis-acting enhancer termed the antioxidant response element (ARE). The products of these genes participate in numerous functions including biotransformation and redox homeostasis, lipid and iron metabolism, inflammation, proteostasis, as well as mitochondrial dynamics and energetics. Thus, it is possible that a single pharmacological NRF2 modulator might mitigate the effect of the main hallmarks of NCDs, including oxidative, proteostatic, inflammatory and/or metabolic stress. Research on model organisms has provided tremendous knowledge of the molecular mechanisms by which NRF2 affects NCDs pathogenesis. This review is a comprehensive summary of the most commonly used model organisms of NCDs in which NRF2 has been genetically or pharmacologically modulated, paving the way for drug development to combat NCDs. We discuss the validity and use of these models and identify future challenges.

Sulforaphane potentiates the efficacy of chemoradiotherapy in glioblastoma by selectively targeting thioredoxin reductase 1

Chemoradiotherapy is a conventional treatment modality for patients with glioblastoma (GBM). However, the efficacy of this approach is significantly hindered by the development of therapeutic resistance. The thioredoxin system, which plays a crucial role in maintaining redox homeostasis, confers protection to cancer cells against apoptosis induced by chemoradiotherapy. Herein, we demonstrate that sulforaphane (SFN), an isothiocyanate phytochemical with anti-cancer effects, inhibits the activity of thioredoxin reductase 1 (TrxR1) through covalent conjugation with residues C59/64/497&U498. This inhibition of TrxR1 leads to the accumulation of reactive oxygen species (ROS), thereby enhancing chemoradiotherapy-induced apoptosis in GBM cells. Furthermore, SFN-induced ROS accumulation facilitates the polarization of M1-like macrophages, which synergistically sensitize GBM tumors to chemoradiotherapy. In conclusion, our study unveils that SFN has potential benefits in improving the effect of chemoradiotherapy and prognosis for GBM patients by targeting TrxR1.

Oxyphylla A exerts antiparkinsonian effects by ameliorating 6-OHDA-induced mitochondrial dysfunction and dyskinesia in vitro and in vivo

Parkinson's disease (PD) poses a formidable challenge in neurology, marked by progressive neuronal loss in the substantia nigra. Despite extensive investigations, understanding PD's pathophysiology remains elusive, with no effective therapeutic intervention identified to alter its course. Oxyphylla A (OPA), a natural compound extracted from Alpinia oxyphylla, exhibits promise in experimental models of various neurodegenerative disorders (ND), notably through novel mechanisms like α-synuclein degradation. The purpose of this investigation was to explore the neuroprotective potential of OPA on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in PD models, with a focus on mitochondrial functions. Additionally, potential OPA targets for neuroprotection were explored. PC12 cells and C57BL/6 mice were lesioned with 6-OHDA as PD models. Impaired mitochondrial membrane potential (Δψm) was assessed using JC-1 staining. The oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were also detected to evaluate mitochondrial function and glucose metabolism in PC12 cells. Behavioral analysis and immunohistochemistry were performed to evaluate pathological lesions in the mouse brain. Moreover, bioinformatics tools predicted OPA targets. OPA restored cellular energy metabolism and mitochondrial biogenesis, preserving Δψm in 6-OHDA-induced neuronal damage. Pre-treatment mitigated loss of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra and striatal dopaminergic fibers, restoring dopamine levels and ameliorating motor deficits in PD mice. Mechanistically, OPA may activate PKA/Akt/GSK-3β and CREB/PGC-1α/NRF-1/TFAM signaling cascades. Bioinformatics analysis identified potential OPA targets, including CTNNB1, ESR1, MAPK1, MAPK14, and SRC. OPA, derived from Alpinia oxyphylla, exhibited promising neuroprotective activity against PD through addressing mitochondrial dysfunction, suggesting its potential as a multi-targeted therapeutic for PD.

Nrf2/Keap1/ARE regulation by plant secondary metabolites: a new horizon in brain tumor management

Brain cancer is regarded as one of the most life-threatening forms of cancer worldwide. Oxidative stress acts to derange normal brain homeostasis, thus is involved in carcinogenesis in brain. The Nrf2/Keap1/ARE pathway is an important signaling cascade responsible for the maintenance of redox homeostasis, and regulation of anti-inflammatory and anticancer activities by multiple downstream pathways. Interestingly, Nrf2 plays a somewhat, contradictory role in cancers, including brain cancer. Nrf2 has traditionally been regarded as a tumor suppressor since its cytoprotective functions are considered to be the principle cellular defense mechanism against exogenous and endogenous insults, such as xenobiotics and oxidative stress. However, hyperactivation of the Nrf2 pathway supports the survival of normal as well as malignant cells, protecting them against oxidative stress, and therapeutic agents. Plants possess a pool of secondary metabolites with potential chemotherapeutic/chemopreventive actions. Modulation of Nrf2/ARE and downstream activities in a Keap1-dependant manner, with the aid of plant-derived secondary metabolites exhibits promise in the management of brain tumors. Current article highlights the effects of Nrf2/Keap1/ARE cascade on brain tumors, and the potential role of secondary metabolites regarding the management of the same.

Neuroprotective Effects of Sulforaphane in a rat model of Alzheimer's Disease induced by Aβ (1-42) peptides

The intricate nature of Alzheimer's disease (AD) has presented significant hurdles in the development of effective interventions. Sulforaphane (SFN) is of interest due to its antioxidative, anti-inflammatory, and neuroprotective properties, which could address various aspects of AD pathology. This study explores the potential of SFN in a rat model of AD induced by Aβ (1-42) peptides. AD symptoms were triggered in rats by injecting Aβ (1-42) peptides directly into their cerebral ventricles. SFN (10 mg/kg and 20 mg/kg), Trigonelline (10 mg/kg), and Pioglitazone (10 mg/kg) were administered in Aβ (1-42) treated animals. Behavioral assessments were performed using the Novel Object Recognition tests. Various biochemical parameters, such as soluble Aβ (1-42), IRS-S312, GSK-3β, TNF-α, acetylcholinesterase, nitrite levels, lipid peroxidation, and reduced glutathione activity, were quantified using ELISA kits and spectrophotometric assays. Histopathological analyses included Hematoxylin and Eosin, Crystal Violet, Congo red, and IRS-1 Immunohistochemistry staining. Quantification was performed to assess neuronal loss and Aβ plaque burden. The novelty of this study lies in its comprehensive evaluation of SFN's impact on multiple AD-related pathways at dual doses. The Novel Object Recognition test revealed that SFN, especially at higher doses, improved memory deficits induced by Aβ (1-42). Biochemically, SFN reduced hippocampal Aβ levels, IRS-S312, GSK-3β, TNF-α, and acetylcholinesterase activity, while increasing glutathione levels, all in a dose-dependent manner. Histopathological analyses further confirmed SFN's protective role against Aβ-induced neuronal damage, amyloidosis, and changes in insulin signaling. These results highlight SFN's potential as a multifaceted therapeutic agent for AD, offering a promising avenue for treatment due to its antioxidative, anti-inflammatory, and neuroprotective properties. The inclusion of combination treatments with Trigonelline and Pioglitazone alongside SFN offers insights into potential synergistic effects, which could pave the way for developing combination therapies for AD.

Bioactivated Glucoraphanin Modulates Genes Involved in Necroptosis on Motor-Neuron-like Nsc-34: A Transcriptomic Study

Research on bioactive compounds has grown recently due to their health benefits and limited adverse effects, particularly in reducing the risk of chronic diseases, including neurodegenerative conditions. According to these observations, this study investigates the activity of sulforaphane (RS-GRA) on an in vitro model of differentiated NSC-34 cells. We performed a transcriptomic analysis at various time points (24 h, 48 h, and 72 h) and RS-GRA concentrations (1 µM, 5 µM, and 10 µM) to identify molecular pathways influenced by this compound and the effects of dosage and prolonged exposure. We found 39 differentially expressed genes consistently up- or downregulated across all conditions. Notably, Nfe2l2, Slc1a5, Slc7a11, Slc6a9, Slc6a5, Sod1, and Sod2 genes were consistently upregulated, while Ripk1, Glul, Ripk3, and Mlkl genes were downregulated. Pathway perturbation analysis showed that the overall dysregulation of these genes results in a significant increase in redox pathway activity (adjusted p-value 1.11 × 10-3) and a significant inhibition of the necroptosis pathway (adjusted p-value 4.64 × 10-3). These findings suggest RS-GRA's potential as an adjuvant in neurodegenerative disease treatment, as both increased redox activity and necroptosis inhibition may be beneficial in this context. Furthermore, our data suggest two possible administration strategies, namely an acute approach with higher dosages and a chronic approach with lower dosages.

Targeting the NRF2 pathway for disease modification in neurodegenerative diseases: mechanisms and therapeutic implications

Neurodegenerative diseases constitute a global health issue and a major economic burden. They significantly impair both cognitive and motor functions, and their prevalence is expected to rise due to ageing societies and continuous population growth. Conventional therapies provide symptomatic relief, nevertheless, disease-modifying treatments that reduce or halt neuron death and malfunction are still largely unavailable. Amongst the common hallmarks of neurodegenerative diseases are protein aggregation, oxidative stress, neuroinflammation and mitochondrial dysfunction. Transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2) constitutes a central regulator of cellular defense mechanisms, including the regulation of antioxidant, anti-inflammatory and mitochondrial pathways, making it a highly attractive therapeutic target for disease modification in neurodegenerative disorders. Here, we describe the role of NRF2 in the common hallmarks of neurodegeneration, review the current pharmacological interventions and their challenges in activating the NRF2 pathway, and present alternative therapeutic approaches for disease modification.

Protective effects of sulforaphane against toxic substances and contaminants: A systematic review

BACKGROUND

Sulforaphane (SFN) is a dietary isothiocyanate, derived from glucoraphanin, present in cruciferous vegetables belonging to the Brassica genus. It is a biologically active phytochemical that acts as a nuclear factor erythroid 2-related factor 2 (Nrf2) inducer. Thus, it has been reported to have multiple protective functions including anticancer responses and protection against a toxic agent's action.

PURPOSE

The present work systematically reviewed and synthesised the protective properties of sulforaphane against a toxic agent. This review reveals the mechanism of the action of SFN in each organ or system.

METHODS

The PRISMA guideline was followed in this sequence: researched literature, organised retrieved documents, abstracted relevant information, assessed study quality and bias, synthesised data, and prepared a comprehensive report. Searches were conducted on Science Direct and PubMed using the keywords "Sulforaphane" AND ("protective effects" OR "protection against").

RESULTS

Reports showed that liver and the nervous system are the target organs on which attention was focused, and this might be due to the key role of oxidative stress in liver and neurodegenerative diseases. However, protective activities have also been demonstrated in the lungs, heart, immune system, kidneys, and endocrine system. SFN exerts its protective effects by activating the Nrf2 pathway, which enhances antioxidant defenses and reduces oxidative stress. It also suppresses inflammation by decreasing interleukin production. Moreover, SFN inhibits apoptosis by preventing caspase 3 cleavage and increasing Bcl2 levels. Overall, SFN demonstrates multifaceted mechanisms to counteract the adverse effects of toxic agents.

CONCLUSION

SFN has potential clinical applications as a chemoprotective agent. Nevertheless, more studies are necessary to set the safe doses of SFN in humans.

Bioactive sulforaphane from cruciferous vegetables: advances in biosynthesis, metabolism, bioavailability, delivery, health benefits, and applications

Chronic inflammation-induced diseases (CID) are the dominant cause of death worldwide, contributing to over half of all global deaths. Sulforaphane (SFN) derived from cruciferous vegetables has been extensively studied for its multiple functional benefits in alleviating CID. This work comprehensively reviewed the biosynthesis, metabolism, bioavailability, delivery, health benefits, and applications of SFN and its potential mechanisms against CID (e.g., cancer, obesity, type 2 diabetes, et al.), and neurological disorders based on a decade of research. SFN exerts its biological functions through the hydrolysis of glucosinolates by gut microbiota, and exhibits rapid metabolism and excretion characteristics via metabolization of mercapturic acid pathway. Microencapsulation is an important way to improve the stability and targeted delivery of SFN. The health benefits of SNF against CID are attributed to the multiple regulatory mechanisms including modulating oxidative stress, inflammation, apoptosis, immune response, and intestinal homeostasis. The clinical applications of SFN and related formulations show promising potential; however, further exploration is required regarding the sources, dosages, toxicity profiles, and stability of SFN. Together, SFN is a natural product with great potential for development and application, which is crucial for the development of functional food and pharmaceutical industries.

Current understanding and future directions of cruciferous vegetables and their phytochemicals to combat neurological diseases

Neurological disorders incidences are increasing drastically due to complex pathophysiology, and the nonavailability of disease-modifying agents. Several attempts have been made to identify new potential chemicals to combat these neurological abnormalities. At present, complete abolishment of neurological diseases is not attainable except for symptomatic relief. However, dietary recommendations to help brain development or improvement have increased over the years. In recent times, cruciferous vegetables and their phytochemicals have been identified from preclinical and clinical investigations as potential neuroprotective agents. The present review highlights the beneficial effects and molecular mechanisms of phytochemicals such as indole-3-carbinol, diindolylmethane, sulforaphane, kaempferol, selenium, lutein, zeaxanthin, and vitamins of cruciferous vegetables against neurological diseases including Parkinson's disease, Alzheimer's disease, stroke, Huntington's disease, autism spectra disorders, anxiety, depression, and pain. Most of these cruciferous phytochemicals protect the brain by eliciting antioxidant, anti-inflammatory, and antiapoptotic properties. Regular dietary intake of cruciferous vegetables may benefit the prevention and treatment of neurological diseases. The present review suggests that there is a lacuna in identifying the clinical efficacy of these phytochemicals. Therefore, high-quality future studies should firmly establish the efficacy of the above-mentioned cruciferous phytochemicals in clinical settings.

J24335 exerts neuroprotective effects against 6-hydroxydopamine-induced lesions in PC12 cells and mice

Parkinson's disease is the second most prevalent age-related neurodegenerative disease and disrupts the lives of people aged >60 years. Meanwhile, single-target drugs becoming inapplicable as PD pathogenesis diversifies. Mitochondrial dysfunction and neurotoxicity have been shown to be relevant to the pathogenesis of PD. The novel synthetic compound J24335 (11-Hydroxy-1-(8-methoxy-5-(trifluoromethyl)quinolin-2-yl)undecan-1-one oxime), which has been researched similarly to J2326, has the potential to be a multi-targeted drug and alleviate these lesions. Therefore, we investigated the mechanism of action and potential neuroprotective function of J24335 against 6-OHDA-induced neurotoxicity in mice, and in PC12 cell models. The key target of action of J24335 was also screened. MTT assay, LDH assay, flow cytometry, RT-PCR, LC-MS, OCR and ECAR detection, and Western Blot analysis were performed to characterize the neuroprotective effects of J24335 on PC12 cells and its potential mechanism. Behavioral tests and immunohistochemistry were used to evaluate behavioral changes and brain lesions in mice. Moreover, bioinformatics was employed to assess the drug-likeness of J24335 and screen its potential targets. J24335 attenuated the degradation of mitochondrial membrane potential and enhanced glucose metabolism and mitochondrial biosynthesis to ameliorate 6-OHDA-induced mitochondrial dysfunction. Animal behavioral tests demonstrated that J24335 markedly improved motor function and loss of TH-positive neurons and dopaminergic nerve fibers, and contributed to an increase in the levels of dopamine and its metabolites in brain tissue. The activation of both the CREB/PGC-1α/NRF-1/TFAM and PKA/Akt/GSK-3β pathways was a major contributor to the neuroprotective effects of J24335. Furthermore, bioinformatics predictions revealed that J24335 is a low toxicity and highly BBB permeable compound targeting 8 key genes (SRC, EGFR, ERBB2, SYK, MAPK14, LYN, NTRK1 and PTPN1). Molecular docking suggested a strong and stable binding between J24335 and the 8 core targets. Taken together, our results indicated that J24335, as a multi-targeted neuroprotective agent with promising therapeutic potential for PD, could protect against 6-OHDA-induced neurotoxicity via two potential pathways in mice and PC12 cells.

Kolaviron neuroprotective effect against okadaic acid-provoked cognitive impairment

Alzheimer's disease (AD) is acknowledged as the main causative factor of dementia that affects millions of people around the world and is increasing at increasing pace. Okadaic acid (OA) is a toxic compound with ability to inhibit protein phosphatases and to induce tau protein hyperphosphorylation and Alzheimer's-like phenotype. Kolaviron (KV) is a bioflavonoid derived from Garcinia kola seeds with anti-antioxidative and anti-inflammation properties. The main goal of this study was to assess whether kolaviron can exert neuroprotective effect against okadaic acid-induced cognitive deficit. Rats had an intracerebroventricular (ICV) injection of OA and pretreated with KV at 50 or 100 mg/kg and examined for cognition besides histological and biochemical factors. OA group treated with KV at 100 mg/kg had less memory deficit in passive avoidance and novel object discrimination (NOD) tasks besides lower hippocampal levels of caspases 1 and 3, tumor necrosis factor α (TNFα) and interleukin 6 (IL-6) as inflammatory factors, reactive oxygen species (ROS), protein carbonyl, malondialdehyde (MDA), and phosphorylated tau (p-tau) and higher level of acetylcholinesterase (AChE) activity, mitochondrial integrity index, superoxide dismutase (SOD), and glutathione (GSH). Moreover, KV pretreatment at 100 mg/kg attenuated hippocampal CA1 neuronal loss and glial fibrillary acidic protein (GFAP) reactivity as a factor of astrogliosis. In summary, KV was able to attenuate cognitive fall subsequent to ICV OA which is partly mediated through its neuroprotective potential linked to mitigation of tau hyperphosphorylation, apoptosis, pyroptosis, neuroinflammation, and oxidative stress and also improvement of mitochondrial health.

Plant sources, extraction techniques, analytical methods, bioactivity, and bioavailability of sulforaphane: a review

Sulforaphane (SFN) is an isothiocyanate commonly found in cruciferous vegetables. It is formed via the enzymatic hydrolysis of glucoraphanin by myrosinase. SFN exerts various biological effects, including anti-cancer, anti-oxidation, anti-obesity, and anti-inflammatory effects, and is widely used in functional foods and clinical medicine. However, the structure of SFN is unstable and easily degradable, and its production is easily affected by temperature, pH, and enzyme activity, which limit its application. Hence, several studies are investigating its physicochemical properties, stability, and biological activity to identify methods to increase its content. This article provides a comprehensive review of the plant sources, extraction and analysis techniques, in vitro and in vivo biological activities, and bioavailability of SFN. This article highlights the importance and provides a reference for the research and application of SFN in the future.

Sulforaphane-A Compound with Potential Health Benefits for Disease Prevention and Treatment: Insights from Pharmacological and Toxicological Experimental Studies

Sulforaphane (SFN), which is a hydrolysis product from glucoraphanin, a compound found in cruciferous vegetables, has been studied for its potential health benefits, particularly in disease prevention and treatment. SFN has proven to be effective in combating different types of cancer by inhibiting the proliferation of tumors and triggering apoptosis. This dual action has been demonstrated to result in a reduction in tumor size and an enhancement of survival rates in animal models. SFN has also shown antidiabetic and anti-obesity effects, improving glucose tolerance and reducing fat accumulation. SFN's ability to activate Nrf2, a transcription factor regulating oxidative stress and inflammation in cells, is a primary mechanism behind its anticancerogenic and antidiabetic effects. Its antioxidant, anti-inflammatory, and anti-apoptotic properties are also suggested to provide beneficial effects against neurodegenerative diseases. The potential health benefits of SFN have led to increased interest in its use as a dietary supplement or adjunct to chemotherapy, but there are insufficient data on its efficacy and optimal doses, as well as its safety. This review aims to present and discuss SFN's potential in treating various diseases, such as cancer, diabetes, cardiovascular diseases, obesity, and neurodegenerative diseases, focusing on its mechanisms of action. It also summarizes studies on the pharmacological and toxicological potential of SFN in in vitro and animal models and explores its protective role against toxic compounds through in vitro and animal studies.

Antagonizing pathological α-synuclein-mediated neurodegeneration by J24335 via the activation of immunoproteasome

The aggregation of misfolded proteins, such as α-synuclein in Parkinson's disease (PD), occurs intracellularly or extracellularly in the majority of neurodegenerative diseases. The immunoproteasome has more potent chymotrypsin-like activity than normal proteasome. Thus, degradation of α-synuclein aggregation via immunoproteasome is an attractive approach for PD drug development. Herein, we aimed to determine if novel compound, 11-Hydroxy-1-(8-methoxy-5-(trifluoromethyl)quinolin-2-yl)undecan-1-one oxime (named as J24335), is a promising candidate for disease-modifying therapy to prevent the pathological progression of neurodegenerative diseases, such as PD. The effects of J24335 on inducible PC12/A53T-α-syn cell viability and cytotoxicity were evaluated by MTT assay and LDH assay, respectively. Evaluation of various proteasome activities was done by measuring the luminescence of enzymatic activity after the addition of different amounts of aminoluciferin. Immunoblotting and real-time PCR were employed to detect the expression of various proteins and genes, respectively. We also used a transgenic mouse model for behavioral testing and immunochemical analysis, to assess the neuroprotective effects of J24335. J24335 inhibited wild-type and mutant α-synuclein aggregation without affecting the growth or death of neuronal cells. The inhibition of α-synuclein aggregation by J24335 was caused by activation of immunoproteasome, as mediated by upregulation of LMP7, and increased cellular chymotrypsin-like activity in 20S proteasome. J24335-enhanced immunoproteasome activity was mediated by PKA/Akt/mTOR pathway activation. Moreover, animal studies revealed that J24335 treatment markedly mitigated both the loss of tyrosine hydroxylase-positive (TH-) neurons and impaired motor skill development. This is the first report to use J24335 as an immunoproteasome enhancing agent to antagonize pathological α-synuclein-mediated neurodegeneration.

Nanophytomedicines as Therapeutic Agents for Parkinson's Disease

Phytochemicals are promising therapeutics for various neurodegenerative disorders, including Parkinson's disease (PD). However, their efficacy, pharmacokinetic properties, and penetration across the blood-brain barrier can be improved using delivery systems such as nanoparticles. We reviewed recently published work in which nanoparticles were used to deliver phytochemicals toward PD treatment. The studies show that nanoparticles not only improve the pharmacological effect of the phytochemicals but also enable targeting to the brain and crossing of the blood-brain barrier. Various ligands were added to the nanoparticles to improve blood-brain barrier transportation. The promising findings from the published studies reveal that more research into nanophytomedicine approaches as therapeutic targets for PD is warranted, especially since they have the potential to protect against key features of PD, including α-synuclein aggregation, mitochondrial dysfunction, and dopaminergic neuronal death. Furthermore, future directions should involve smart designs to tailor nanoparticles for improved therapeutic delivery by modifying their features, such as architecture, surface and material properties, targeting ligands, and responsiveness.

Oxidative stress, the blood-brain barrier and neurodegenerative diseases: The critical beneficial role of dietary antioxidants

In recent years, growing awareness of the role of oxidative stress in brain health has prompted antioxidants, especially dietary antioxidants, to receive growing attention as possible treatments strategies for patients with neurodegenerative diseases (NDs). The most widely studied dietary antioxidants include active substances such as vitamins, carotenoids, flavonoids and polyphenols. Dietary antioxidants are found in usually consumed foods such as fresh fruits, vegetables, nuts and oils and are gaining popularity due to recently growing awareness of their potential for preventive and protective agents against NDs, as well as their abundant natural sources, generally non-toxic nature, and ease of long-term consumption. This review article examines the role of oxidative stress in the development of NDs, explores the 'two-sidedness' of the blood-brain barrier (BBB) as a protective barrier to the nervous system and an impeding barrier to the use of antioxidants as drug medicinal products and/or dietary antioxidants supplements for prevention and therapy and reviews the BBB permeability of common dietary antioxidant suplements and their potential efficacy in the prevention and treatment of NDs. Finally, current challenges and future directions for the prevention and treatment of NDs using dietary antioxidants are discussed, and useful information on the prevention and treatment of NDs is provided.

The untapped potential of targeting NRF2 in neurodegenerative disease

Since its initial discovery almost three decades ago, the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) has been shown to regulate a host of downstream transcriptional responses and play a critical role in preventing or promoting disease progression depending on the context. Critically, while the importance of proper nuclear factor erythroid 2-related factor 2 function has been demonstrated across a variety of pathological settings, the ability to progress NRF2-targeted therapeutics to clinic has remained frustratingly elusive. This is particularly true in the case of age-related pathologies, where nuclear factor erythroid 2-related factor 2 is a well-established mitigator of many of the observed pathogenic effects, yet options to target this pathway remain limited. Along these lines, loss of nuclear factor erythroid 2-related factor 2 function has clearly been shown to enhance neuropathological outcomes, with enhancing nuclear factor erythroid 2-related factor 2 pathway activation to prevent neurodegenerative/neurological disease progression continuing to be an active area of interest. One critical obstacle in generating successful therapeutics for brain-related pathologies is the ability of the compound to cross the blood brain barrier (BBB), which has also hampered the implementation of several promising nuclear factor erythroid 2-related factor 2 inducers. Another limitation is that many nuclear factor erythroid 2-related factor 2 activators have undesirable off-target effects due to their electrophilic nature. Despite these constraints, the field has continued to evolve, and several viable means of targeting nuclear factor erythroid 2-related factor 2 in a neuropathological context have emerged. In this perspective, we will briefly discuss the key findings and promising therapeutic options that have been discovered to date, as well as highlight emerging areas of NRF2-neurodegeneration research that provide hope for successfully targeting this pathway in the future.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

Lima B, Araújo AAS, de Albuquerque-Junior RLC, Gramacho KP, Padilha FF, da Costa LP, Severino P, Cardoso JC, Souto EB, Gomes MZ. Africanized Bee Venom (Apis mellifera Linnaeus): Neuroprotective Effects in a Parkinson's Disease Mouse Model Induced by 6-hydroxydopamine

This study evaluated the neuroprotective effects of the Africanized bee venom (BV) and its mechanisms of action after 6-hydroxydopamine-(6-OHDA)-induced lesion in a mice model. Prior to BV treatment, mice received intrastriatal microinjections of 6-OHDA (no induced dopaminergic neuronal death) or ascorbate saline (as a control). BV was administered subcutaneously at different dosages (0.01, 0.05 or 0.1 mg·Kg^-1) once every two days over a period of 3 weeks. The open field test was carried out, together with the immunohistochemical and histopathological analysis. The chemical composition of BV was also assessed, identifying the highest concentrations of apamin, phospholipase A₂ and melittin. In the behavioral evaluation, the BV (0.1 mg·Kg^-1) counteracted the 6-OHDA-induced decrease in crossings and rearing. 6-OHDA caused loss of dopaminergic cell bodies in the substantia nigra pars compacta and fibers in striatum (STR). Mice that received 0.01 mg·Kg^-1 showed significant increase in the mean survival of dopaminergic cell bodies. Increased astrocytic infiltration occurred in the STR of 6-OHDA injected mice, differently from those of the groups treated with BV. The results suggested that Africanized BV has neuroprotective activity in an animal model of Parkinson's disease.

Glucoraphanin Triggers Rapid Antidepressant Responses in a Rat Model of Beta Amyloid-Induced Depressive-like Behaviour

Glucoraphanin (GRA) is a natural compound that has shown beneficial effects in chronic diseases and in central nervous system disorders. Moreover, GRA displayed antidepressant activity in preclinical models. We have previously demonstrated that a single intracerebroventricular administration of soluble amyloid-beta 1-42 (sAβ 1-42) in rat evokes a depressive-like phenotype by increasing immobility frequency in the forced swimming test (FST). The aim of this work was to investigate the effect of GRA in naïve and in sAβ-1-42-treated rats by using the FST. Behavioural analyses were accompanied by neurochemical and biochemical measurements in the prefrontal cortex (PFC), such as serotonin (5-HT), noradrenaline (NA), kynurenine (KYN), tryptophan (TRP), reactive oxygen species (ROS) and the transcription nuclear factor kappa B (NF-kB) levels. We reported that GRA administration in naïve rats at the dose of 50 mg/kg reduced the immobility frequency in the FST and increased 5-HT and NA levels in the PFC compared to controls. At the same dose, GRA reverted depressive-like effects of sAβ 1-42 administration, restored the 5-HT levels and reduced NF-kB, KYN and ROS levels in PFC. In conclusion, GRA rapidly reverting depressive-like behaviour, together with biochemical and neurochemical alterations, might represent a safe and natural candidate for the treatment of depression.

Long-term sulforaphane-treatment restores redox homeostasis and prevents cognitive decline in middleaged female and male rats, but cannot revert previous damage in old animals

Aging is a complex and detrimental process, which disrupts most organs and systems within the organisms. The nervous system is morphologically and functionally affected during normal aging, and oxidative stress has been involved in age-related damage, leading to cognitive decline and neurodegenerative processes. Sulforaphane (SFN) is a hormetin that activates the antioxidant and anti-inflammatory responses. So, we aimed to evaluate if SFN long-term treatment was able to prevent age-associated cognitive decline in adult and old female and male rats. Memory was evaluated in adult (15-month-old), and old (21-month-old) female and male Wistar rats after three months of SFN treatment. Young rats (4-month-old) were used as age controls. The antioxidant response induction, the redox state (GSH/GSSG), and oxidative damage were determined in the brain cortex (Cx) and hippocampus (Hc). Our results showed that SFN restored redox homeostasis in the Cx and Hc of adult rats, thus preventing cognitive decline in both sexes; however, the redox responses were not the same in males and females. Old rats were not able to recover their redox state as adults did, but they had a mild improvement. These results suggest that SFN mainly prevents rather than reverts neural damage; though, there might also be a range of opportunities to use hormetins like SFN, to improve redox modulation in old animals.

Sulforaphane Acts Through NFE2L2 to Prevent Hypoxia-Induced Apoptosis in Porcine Granulosa Cells via Activating Antioxidant Defenses and Mitophagy

In mammals, a vast majority of ovarian follicles undergo atresia, which is caused by granulosa cell (GC) apoptosis. GCs in follicles are exposed to low oxygen. Hypoxia triggers reactive oxygen species (ROS) generation, which leads to cell oxidative stress and apoptosis. Sulforaphane (SFN), a phytochemical isothiocyanate enriched in cruciferous vegetables, has exhibited a crucial role in mitigating oxidative stress. To explore the effect of SFN on porcine GC apoptosis in a hypoxic environment, we handled the established hypoxia model (1% O₂) of cultured porcine GCs with SFN. Results showed that SFN rescued hypoxia-induced apoptosis and viability of GCs. Meanwhile, SFN increased the expression of antioxidant enzymes and reduced the accumulation of ROS in GC cytoplasm and mitochondria under hypoxia. Mechanically, SFN activated the transcription factor of redox-sensitive nuclear factor-erythroid 2-related factor 2 (NFE2L2) entering the nucleus, further inducing mitophagy and increased antioxidant capacity, finally alleviating the adverse effect of hypoxia on porcine GCs. In conclusion, SFN inhibited hypoxia-evoked GC apoptosis by activating antioxidant defenses and mitophagy through NFE2L2. New targets may be provided for regulating follicular development and atresia by these findings.

Protective effects of functional foods against Parkinson's disease: A narrative review on pharmacology, phytochemistry, and molecular mechanisms

In Persian Medicine (PM), PD (brain-based tremor) is a known CNS disorder with several therapeutic and preventive options. In their medical textbooks and pharmacopeias, Persian great scientists such as Rhazes (854-925 AD), Avicenna (980-1037 AD), and Jorjani (1042-1136 AD), have discussed pharmacological and nutritional strategies for the prevention, slowing progression, and treatment of PD. In the present study, we surveyed plant- and animal-based foods recommended by PM for the prevention and treatment of CNS-related tremors. In vivo and in-vitro pharmacological evidence supporting the beneficial effects of PM-recommended foods in prevention and alleviating PD, major active phytochemicals along with the relevant mechanisms of action were studied. Several PM plants possess potent antioxidant, antiinflammatory, and PD preventing properties. Garlic and allicin, cabbage and isothiocyanates, chickpea seed and its O-methylated isoflavones biochanin A and formononetin, cinnamon, and cinnamaldehyde, saffron and its crocin, crocetin, and safranal, black cumin and its thymoquinone, black pepper and piperine, pistachio and genistein and daidzein, and resveratrol are among the most effective dietary itemsagainst PD. They act through attenuating neurotoxin-induced memory loss and behavioral impairment, oxidative stress, and dopaminergic cell death. PM-recommended foods can help alleviate PD progression and also discovering and developing new neuroprotective anti-PD pharmaceuticals.

Redox modulation by plant polyphenols targeting vitagenes for chemoprevention and therapy: Relevance to novel anti-cancer interventions and mini-brain organoid technology

The scientific community, recently, has focused notable attention on the chemopreventive and therapeutic effects of dietary polyphenols for human health. Emerging evidence demonstrates that polyphenols, flavonoids and vitamins counteract and neutralize genetic and environmental stressors, particularly oxidative stress and inflammatory process closely connected to cancer initiation, promotion and progression. Interestingly, polyphenols can exert antioxidant or pro-oxidant cytotoxic effects depending on their endogenous concentration. Notably, polyphenols at high dose act as pro-oxidants in a wide type of cancer cells by inhibiting Nrf2 pathway and the expression of antioxidant vitagenes, such as NAD(P)H-quinone oxidoreductase (NQO1), glutathione transferase (GT), GPx, heme oxygenase-1 (HO-1), sirtuin-1 (Sirt1) and thioredoxin (Trx) system which play an essential role in the metabolism of reactive oxygen species (ROS), detoxification of xenobiotics and inhibition of cancer progression, by inducing apoptosis and cell cycle arrest according to the hormesis approach. Importantly, mutagenesis of Nrf2 pathway can exacerbate its "dark side" role, representing a crucial event in the initiation stage of carcinogenesis. Herein, we review the hormetic effects of polyphenols and nanoincapsulated-polyphenols in chemoprevention and treatment of brain tumors via activation or inhibition of Nrf2/vitagenes to suppress carcinogenesis in the early stages, and thus inhibit its progression. Lastly, we discuss innovative preclinical approaches through mini-brain tumor organoids to study human carcinogenesis, from basic cancer research to clinical practice, as promising tools to recapitulate the arrangement of structural neuronal tissues and biological functions of the human brain, as well as test drug toxicity and drive personalized and precision medicine in brain cancer.

A Perspective on Nrf2 Signaling Pathway for Neuroinflammation: A Potential Therapeutic Target in Alzheimer's and Parkinson's Diseases

Neuroinflammation plays a pivotal role in Alzheimer's disease (AD) and Parkinson's disease (PD), the leading causes of dementia. These neurological disorders are characterized by the accumulation of misfolded proteins such as amyloid-ß (Aß), tau protein and α-synuclein, contributing to mitochondrial fragmentation, oxidative stress, and neuroinflammation. Misfolded proteins activate microglia, which induces neuroinflammation, expression of pro-inflammatory cytokines and subsequently facilitates synaptic damage and neuronal loss. So far, all the proposed drugs were based on the inhibition of protein aggregation and were failed in clinical trials. Therefore, the treatment options of dementia are still a challenging issue. Thus, it is worthwhile to study alternative therapeutic strategies. In this context, there is increasing data on the pivotal role of transcription factor NF- E2 p45-related factor 2 (Nrf2) on the redox homeostasis and anti-inflammatory functions in neurodegenerative disorders. Interestingly, Nrf2 signaling pathway has shown upregulation of antioxidant genes, inhibition of microglia-mediated inflammation, and improved mitochondrial function in neurodegenerative diseases, suggesting Nrf2 activation could be a novel therapeutic approach to target pathogenesis. The present review will examine the correlation between Nrf2 signaling with neuroinflammation in AD and PD.

Beneficial Health Effects of Glucosinolates-Derived Isothiocyanates on Cardiovascular and Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) and cardiovascular diseases (CVDs) are illnesses that affect the nervous system and heart, all of which are vital to the human body. To maintain health of the human body, vegetable diets serve as a preventive approach and particularly Brassica vegetables have been associated with lower risks of chronic diseases, especially NDDs and CVDs. Interestingly, glucosinolates (GLs) and isothiocyanates (ITCs) are phytochemicals that are mostly found in the Cruciferae family and they have been largely documented as antioxidants contributing to both cardio- and neuroprotective effects. The hydrolytic breakdown of GLs into ITCs such as sulforaphane (SFN), phenylethyl ITC (PEITC), moringin (MG), erucin (ER), and allyl ITC (AITC) has been recognized to exert significant effects with regards to cardio- and neuroprotection. From past in vivo and/or in vitro studies, those phytochemicals have displayed the ability to mitigate the adverse effects of reactive oxidation species (ROS), inflammation, and apoptosis, which are the primary causes of CVDs and NDDs. This review focuses on the protective effects of those GL-derived ITCs, featuring their beneficial effects and the mechanisms behind those effects in CVDs and NDDs.

Drug Delivery of Natural Products Through Nanocarriers for Effective Breast Cancer Therapy: A Comprehensive Review of Literature

Despite recent advances in the diagnosis and treatment of breast cancer (BC), it remains a global health issue affecting millions of women annually. Poor prognosis in BC patients is often linked to drug resistance as well as the lack of effective therapeutic options for metastatic and triple-negative BC. In response to these unmet needs, extensive research efforts have been devoted to exploring the anti-BC potentials of natural products owing to their multi-target mechanisms of action and good safety profiles. Various medicinal plant extracts/essential oils and natural bioactive compounds have demonstrated anti-cancer activities in preclinical BC models. Despite the promising preclinical results, however, the clinical translation of natural products has often been hindered by their poor stability, aqueous solubility and bioavailability. There have been attempts to overcome these limitations, particularly via the use of nano-based drug delivery systems (NDDSs). This review highlights the tumour targeting mechanisms of NDDSs, the advantages and disadvantages of the major classes of NDDSs and their current clinical status in BC treatment. Besides, it also discusses the proposed anti-BC mechanisms and nanoformulations of nine medicinal plants' extracts/essential oils and nine natural bioactive compounds; selected via the screening of various scientific databases, including PubMed, Scopus and Google Scholar, based on the following keywords: "Natural Product AND Nanoparticle AND Breast Cancer". Overall, these nanoformulations exhibit improved anti-cancer efficacy against preclinical BC models, with some demonstrating biocompatibility with normal cell lines and mouse models. Further clinical studies are, however, warranted to ascertain their efficacy and biocompatibility in humans.

Glucosinolates From Cruciferous Vegetables and Their Potential Role in Chronic Disease: Investigating the Preclinical and Clinical Evidence

An increasing body of evidence highlights the strong potential for a diet rich in fruit and vegetables to delay, and often prevent, the onset of chronic diseases, including cardiometabolic, neurological, and musculoskeletal conditions, and certain cancers. A possible protective component, glucosinolates, which are phytochemicals found almost exclusively in cruciferous vegetables, have been identified from preclinical and clinical studies. Current research suggests that glucosinolates (and isothiocyanates) act via several mechanisms, ultimately exhibiting anti-inflammatory, antioxidant, and chemo-protective effects. This review summarizes the current knowledge surrounding cruciferous vegetables and their glucosinolates in relation to the specified health conditions. Although there is evidence that consumption of a high glucosinolate diet is linked with reduced incidence of chronic diseases, future large-scale placebo-controlled human trials including standardized glucosinolate supplements are needed.

Sulforaphane Causes Cell Cycle Arrest and Apoptosis in Human Glioblastoma U87MG and U373MG Cell Lines under Hypoxic Conditions

Glioblastoma multiforme (GBM) is the most prevalent and aggressive primary brain tumor. The median survival rate from diagnosis ranges from 15 to 17 months because the tumor is resistant to most therapeutic strategies. GBM exhibits microvascular hyperplasia and pronounced necrosis triggered by hypoxia. Sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables, has already demonstrated the ability to inhibit cell proliferation, by provoking cell cycle arrest, and leading to apoptosis in many cell lines. In this study, we investigated the antineoplastic effects of SFN [20-80 μM for 48 h] in GBM cells under normoxic and hypoxic conditions. Cell viability assays, flow cytometry, and Western blot results revealed that SFN could induce apoptosis of GBM cells in a dose-dependent manner, under both conditions. In particular, SFN significantly induced caspase 3/7 activation and DNA fragmentation. Moreover, our results demonstrated that SFN suppressed GBM cells proliferation by arresting the cell cycle at the S-phase, also under hypoxic condition, and that these effects may be due in part to its ability to induce oxidative stress by reducing glutathione levels and to increase the phosphorylation of extracellular signal-regulated kinases (ERKs). Overall, we hypothesized that SFN treatment might serve as a potential therapeutic strategy, alone or in combination, against GBM.

Brain-Protective Mechanisms of Transcription Factor NRF2: Toward a Common Strategy for Neurodegenerative Diseases

Neurodegenerative diseases are characterized by the loss of homeostatic functions that control redox and energy metabolism, neuroinflammation, and proteostasis. The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is a master controller of these functions, and its overall activity is compromised during aging and in these diseases. However, NRF2 can be activated pharmacologically and is now being considered a common therapeutic target. Many gaps still exist in our knowledge of the specific role that NRF2 plays in specialized brain cell functions or how these cells respond to the hallmarks of these diseases. This review discusses the relevance of NRF2 to several hallmark features of neurodegenerative diseases and the current status of pharmacological activators that might pass through the blood-brain barrier and provide a disease-modifying effect. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Proper Diet and Regular Physical Activity Slow Down the Development of Parkinson Disease

From year to year, we know more about neurodegeneration and Parkinson’s disease (PD). A positive influence of various types of physical activity is more often described in the context of neuroprotection and prevention as well as the form of rehabilitation in Parkinson’s patients. Moreover, when we look at supplementation, clinical nutrition and dietetics, we will see that balancing consumed products and supplementing the vitamins or minerals is necessary. Considering the biochemical pathways in skeletal muscle, we may see that many researchers desire to identify molecular mediators that have an impact through exercise and balanced diet on human health or development of the neurodegenerative disease. Therefore, it is mandatory to study the potential mechanism(s) related to diet and factors resulted from physical activity as molecular mediators, which play a therapeutic role in PD. This review summarizes the available literature on mechanisms and specific pathways involved in diet-exercise relationship and discusses how therapy, including appropriate exercises and diet that influence molecular mediators, may significantly slow down the progress of neurodegenerative processes. We suggest that a proper diet combined with physical activity will be a good solution for psycho-muscle BALANCE not only in PD but also in other neurodegenerative diseases.

Redox Homeostasis and Prospects for Therapeutic Targeting in Neurodegenerative Disorders

Reactive species, such as those of oxygen, nitrogen, and sulfur, are considered part of normal cellular metabolism and play significant roles that can impact several signaling processes in ways that lead to either cellular sustenance, protection, or damage. Cellular redox processes involve a balance in the production of reactive species (RS) and their removal because redox imbalance may facilitate oxidative damage. Physiologically, redox homeostasis is essential for the maintenance of many cellular processes. RS may serve as signaling molecules or cause oxidative cellular damage depending on the delicate equilibrium between RS production and their efficient removal through the use of enzymatic or nonenzymatic cellular mechanisms. Moreover, accumulating evidence suggests that redox imbalance plays a significant role in the progression of several neurodegenerative diseases. For example, studies have shown that redox imbalance in the brain mediates neurodegeneration and alters normal cytoprotective responses to stress. Therefore, this review describes redox homeostasis in neurodegenerative diseases with a focus on Alzheimer's and Parkinson's disease. A clearer understanding of the redox-regulated processes in neurodegenerative disorders may afford opportunities for newer therapeutic strategies.

Nrf2 Activation Attenuates Acrylamide-Induced Neuropathy in Mice

Acrylamide is a well characterized neurotoxicant known to cause neuropathy and encephalopathy in humans and experimental animals. To investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in acrylamide-induced neuropathy, male C57Bl/6JJcl adult mice were exposed to acrylamide at 0, 200 or 300 ppm in drinking water and co-administered with subcutaneous injections of sulforaphane, a known activator of the Nrf2 signaling pathway at 0 or 25 mg/kg body weight daily for 4 weeks. Assessments for neurotoxicity, hepatotoxicity, oxidative stress as well as messenger RNA-expression analysis for Nrf2-antioxidant and pro-inflammatory cytokine genes were conducted. Relative to mice exposed only to acrylamide, co-administration of sulforaphane protected against acrylamide-induced neurotoxic effects such as increase in landing foot spread or decrease in density of noradrenergic axons as well as hepatic necrosis and hemorrhage. Moreover, co-administration of sulforaphane enhanced acrylamide-induced mRNA upregulation of Nrf2 and its downstream antioxidant proteins and suppressed acrylamide-induced mRNA upregulation of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS) in the cerebral cortex. The results demonstrate that activation of the Nrf2 signaling pathway by co-treatment of sulforaphane provides protection against acrylamide-induced neurotoxicity through suppression of oxidative stress and inflammation. Nrf2 remains an important target for the strategic prevention of acrylamide-induced neurotoxicity.

Sulforaphane enhances long-term potentiation and ameliorate scopolamine-induced memory impairment

Increases in human life expectancy have led to increases in the prevalence of senile dementia and neurodegenerative diseases. This is a major problem because there are no curative treatments for these diseases, and patients with unmanaged cognitive and neurodegenerative symptoms experience many social problems. Sulforaphane is a type of organosulfur compound known as an isothiocyanate. It is derived from glucoraphanin, a compound found in cruciferous vegetables such as broccoli, brussels sprouts, and cabbages, via an enzymatic reaction that is triggered by plant damage (e.g., chewing). Sulforaphane exhibits activity against cancer, inflammation, depression, and severe cardiac diseases. It can also alleviate oxidative stress and neural dysfunction in the brain. However, there is insufficient knowledge about the electrophysiological and behavioral basis of the effects of sulforaphane on learning and memory. Therefore, we evaluated whether acute sulforaphane administration affected long-term potentiation (LTP) in organotypic cultured rat hippocampal tissues. We also measured the effect of sulforaphane on the performance of three behavioral tests, the Y-maze test, the passive avoidance test, and the Morris water maze, which assess short-term memory, avoidance memory, and short and long-term spatial memory, respectively. We found that sulforaphane increased the total field excitatory postsynaptic potential (fEPSP) in a dose-dependent manner after high frequency stimulation and attenuated scopolamine-induced interference of the fEPSP in the hippocampal CA1 area. Sulforaphane also restored cognitive function and inhibited memory impairment as indicated by the alleviation of the negative neurological effects of scopolamine, i.e, a lowered ratio of spontaneous alternation in the Y-maze, a reduced step-through latency in the passive avoidance test, and an increased navigation time in the Morris water maze. These results indicate that sulforaphane can effectively prevent the attenuation of LTP and cognitive abilities induced by cholinergic and muscarinic receptor blockade. Further research is warranted to explore the potential therapeutic and prophylactic utility of sulforaphane for improving learning and memory, especially in those suffering from neurodegenerative disorders.

Current analytical methods for determination of glucosinolates in vegetables and human tissues

Numerous epidemiological studies have indicated the potential effects of glucosinolates and their metabolites against cancer as well as other non-communicable diseases, such as cardiovascular disease and neurodegenerative disorders. However, information on the presence and quantity of glucosinolates in commonly consumed vegetables and in human fluids is sparse, largely because well-standardised methods for glucosinolate determination are not available, resulting in published data being inconsistent and conflicting. Thus, studies published since 2002 on the most recent developments of glucosinolate extraction and identification have been collected and reviewed with emphasis on determination of the intact glucosinolates by LC-MS and LC-MS/MS. This overview highlights the glucosinolate extraction methods used, the stability of glucosinolates during extraction, the availability of stable isotope labelled internal standards and the use of NMR for purity analysis, as well as the current analytical techniques that have been applied for glucosinolate analysis, e.g. liquid chromatography with mass spectrometric detection (LC-MS). It aims to interpret the findings with a focus on the development of a validated method, which will help to determine the glucosinolate content of vegetative plants and human tissues, and the identification and determination of selected glucosinolate metabolites.

Natural products in drug discovery: advances and opportunities

Natural products and their structural analogues have historically made a major contribution to pharmacotherapy, especially for cancer and infectious diseases. Nevertheless, natural products also present challenges for drug discovery, such as technical barriers to screening, isolation, characterization and optimization, which contributed to a decline in their pursuit by the pharmaceutical industry from the 1990s onwards. In recent years, several technological and scientific developments - including improved analytical tools, genome mining and engineering strategies, and microbial culturing advances - are addressing such challenges and opening up new opportunities. Consequently, interest in natural products as drug leads is being revitalized, particularly for tackling antimicrobial resistance. Here, we summarize recent technological developments that are enabling natural product-based drug discovery, highlight selected applications and discuss key opportunities.

PERK Pathway and Neurodegenerative Disease: To Inhibit or to Activate?

With the extension of life span in recent decades, there is an increasing burden of late-onset neurodegenerative diseases, for which effective treatments are lacking. Neurodegenerative diseases include the widespread Alzheimer’s disease (AD) and Parkinson’s disease (PD), the less frequent Huntington’s disease (HD) and Amyotrophic Lateral Sclerosis (ALS) and also rare early-onset diseases linked to mutations that cause protein aggregation or loss of function in genes that maintain protein homeostasis. The difficulties in applying gene therapy approaches to tackle these diseases is drawing increasing attention to strategies that aim to inhibit cellular toxicity and restore homeostasis by intervening in cellular pathways. These include the unfolded protein response (UPR), activated in response to endoplasmic reticulum (ER) stress, a cellular affliction that is shared by these diseases. Special focus is turned to the PKR-like ER kinase (PERK) pathway of the UPR as a target for intervention. However, the complexity of the pathway and its ability to promote cell survival or death, depending on ER stress resolution, has led to some confusion in conflicting studies. Both inhibition and activation of the PERK pathway have been reported to be beneficial in disease models, although there are also some reports where they are counterproductive. Although with the current knowledge a definitive answer cannot be given on whether it is better to activate or to inhibit the pathway, the most encouraging strategies appear to rely on boosting some steps without compromising downstream recovery.

Andrographolide upregulates protein quality control mechanisms in cell and mouse through upregulation of mTORC1 function

BACKGROUND

Heat shock response (HSR), a component of cellular protein quality control mechanisms, is defective in different neurodegenerative conditions such as Parkinson's disease (PD). Forced upregulation of heat shock factor 1 (HSF1), an HSR master regulator, showed therapeutic promise in PD models. Many of the reported small-molecule HSF1 activators have limited functions. Therefore, identification and understanding the molecular bases of action of new HSF1 activating molecules is necessary.

METHOD

We used a cell-based reporter system to screen Andrographis paniculata leaf extract to isolate andrographolide as an inducer of HSF1 activity. The andrographolide activity was characterized by analyzing its role in different protein quality control mechanisms.

RESULT

We find that besides ameliorating the PD in MPTP-treated mice, andrographolide upregulated different machineries controlled by HSF1 and NRF2 in both cell and mouse brain. Andrographolide achieves these functions through mTORC1 activated via p38 MAPK and ERK pathways. NRF2 activation is reflected in the upregulation of proteasome as well as autophagy pathways. We further show that NRF2 activation is mediated through mTORC1 driven phosphorylation of p62/sequestosome 1. Studies with different cell types suggested that andrographolide-mediated induction of ROS level underlies all these activities in agreement with the upregulation of mTORC1 and NRF2-antioxidant pathway in mice.

CONCLUSION

Andrographolide through upregulating HSF1 activity ameliorates protein aggregation induced cellular toxicity.

GENERAL SIGNIFICANCE

Our results provide a reasonable basis for use of andrographolide in the therapy regimen for the treatment of PD.

Paeonol Protection Against Intrastriatal 6-Hydroxydopamine Rat Model of Parkinson's Disease

Introduction:

Parkinson’s Disease (PD) presentations comprise frequent movement disorders in the elderly with various symptoms consisting of motor and non-motor complications. Paeonol is a phenolic chemical agent that has shown antioxidant and anti-inflammatory effects in different disorders and promising effects on metabotropic glutamate receptors (mGluR)- and GABAA-mediated neurotransmission. In this research, we tried to show the neuroprotective potential of paeonol in rat PD model induced by intrastriatal 6-hydroxydopamine (6-OHDA).

Methods:

Rats with intrastriatal 6-OHDA lesioning received with paeonol at a dosage of 100 mg/kg/d for one week. In the end, some biomarkers of oxidative stress, apoptosis, and astrogliosis in nigral and striatal tissues were evaluated in addition to behavioral and Tyrosine Hydroxylase (TH) immunohistochemical analysis.

Results:

The obtained data showed that paeonol alleviates apomorphine-induced rotations and reduces the delay time to initiate and the total time in the narrow beam test. However, its beneficial behavioral effect vanished after intracerebroventricular administration of mGluR III or GABAA receptor antagonists. Moreover, paeonol significantly restored striatal malondialdehyde, tissue levels of reactive oxygen species, the activity of the protective and vital enzymes consisting of superoxide dismutase and catalase, Glial Fibrillary Acidic Protein (GFAP), DNA fragmentation, phosphor apoptosis signal-regulating kinase 1, and nigral aquaporin 4 with no significant and proper change of nitrite, interleukin-1β, inducible nitric oxide synthase, and angiotensin II. Additionally, paeonol prevented injury and reduced tyrosine hydroxylase-containing neurons in the midbrain nigral tissue.

Conclusion:

These obtained findings evidently designate neuroprotective property of paeonol in 6-OHDA murine model of PD that is exerted via easing of oxidative stress, apoptosis, astrogliosis, and its advantageous effect is to some extent mediated via mGluR III/GABAA pathway.

Cruciferous vegetables: rationale for exploring potential salutary effects of sulforaphane-rich foods in patients with chronic kidney disease

Sulforaphane (SFN) is a sulfur-containing isothiocyanate found in cruciferous vegetables (Brassicaceae) and a well-known activator of nuclear factor-erythroid 2-related factor 2 (Nrf2), considered a master regulator of cellular antioxidant responses. Patients with chronic diseases, such as diabetes, cardiovascular disease, cancer, and chronic kidney disease (CKD) present with high levels of oxidative stress and a massive inflammatory burden associated with diminished Nrf2 and elevated nuclear transcription factor-κB-κB expression. Because it is a common constituent of dietary vegetables, the salutogenic properties of sulforaphane, especially it’s antioxidative and anti-inflammatory properties, have been explored as a nutritional intervention in a range of diseases of ageing, though data on CKD remain scarce. In this brief review, the effects of SFN as a senotherapeutic agent are described and a rationale is provided for studies that aim to explore the potential benefits of SFN-rich foods in patients with CKD.

Neuronal degeneration and oxidative stress in the SNc of 6-OHDA intoxicated rats; improving role of silymarin long-term treatment

Progressive loss in dopaminergic neurons (DA) of substantia nigra pars compacta (SNc) leads to Parkinson's disease with a hypothesis of oxidative stress generation. The present study was conducted to determine the long-term efficacy of silymarin (SM) post-treatment on 6-OHDA-induced oxidative stress in the SNc of male rats. Male Wistar rats were received 6-OHDA (8 μg/rat) into SNc. After 3 weeks, as recovery period, the animals were treated with i.p. injection of SM at different doses of 100, 200, or 300 mg/kg for 15 days. At the end of the treatment, motor function, neuronal cell count, antioxidant enzymes, and lipid peroxidation and tyrosine hydroxylase (TH) activities were evaluated in the ventral midbrain tissue. The 6-OHDA significantly decreased (p ≤ 0.05) motor function, antioxidant enzyme activity, GSH level, and GSH/GSSG ratio and caused an augmentation in GSSG and lipid peroxidation level. The 6-OHDA also reduced the population of neurons and TH expression. The SM repaired the 6-OHDA-induced motor impairment, antioxidant enzyme suppression, and TH down-regulation. All three doses of SM could restore the MDA level to the normal range in the 6-OHDA-lesioned rats and could reversed the effect of 6-OHDA on GSH, GSSG level, and GSH/GSSG ratio. The SM treatment significantly and dose-dependently increased (p ≤ 0.001) the total number of surviving neurons in the SNc. Silymarin chronic treatment restored the brain's antioxidant capacity and salvaged neurons from oxidative stress-induced neurodegeneration. The SM could also improve motor function in parkinsonian animals by increasing TH expression. These results recommend that application of SM over initial clinical stages may depict a hopeful approach versus PD. However, more research is needed to confirm this issue.

Efficacy of Sulforaphane in Neurodegenerative Diseases

Sulforaphane (SFN) is a phytocompound belonging to the isothiocyanate family. Although it was also found in seeds and mature plants, SFN is mainly present in sprouts of many cruciferous vegetables, including cabbage, broccoli, cauliflower, and Brussels sprouts. SFN is produced by the conversion of glucoraphanin through the enzyme myrosinase, which leads to the formation of this isothiocyanate. SFN is especially characterized by antioxidant, anti-inflammatory, and anti-apoptotic properties, and for this reason, it aroused the interest of researchers. The aim of this review is to summarize the experimental studies present on Pubmed that report the efficacy of SFN in the treatment of neurodegenerative disease, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and multiple sclerosis (MS). Therefore, thanks to its beneficial effects, SFN could be useful as a supplement to counteracting neurodegenerative diseases.

Attenuation of Nrf2/Keap1/ARE in Alzheimer's Disease by Plant Secondary Metabolites: A Mechanistic Review

Alzheimer’s disease (AD) is a progressive neuronal/cognitional dysfunction, leading to disability and death. Despite advances in revealing the pathophysiological mechanisms behind AD, no effective treatment has yet been provided. It urges the need for finding novel multi-target agents in combating the complex dysregulated mechanisms in AD. Amongst the dysregulated pathophysiological pathways in AD, oxidative stress seems to play a critical role in the pathogenesis progression of AD, with a dominant role of nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein-1 (Keap1)/antioxidant responsive elements (ARE) pathway. In the present study, a comprehensive review was conducted using the existing electronic databases, including PubMed, Medline, Web of Science, and Scopus, as well as related articles in the field. Nrf2/Keap1/ARE has shown to be the upstream orchestrate of oxidative pathways, which also ameliorates various inflammatory and apoptotic pathways. So, developing multi-target agents with higher efficacy and lower side effects could pave the road in the prevention/management of AD. The plant kingdom is now a great source of natural secondary metabolites in targeting Nrf2/Keap1/ARE. Among natural entities, phenolic compounds, alkaloids, terpene/terpenoids, carotenoids, sulfur-compounds, as well as some other miscellaneous plant-derived compounds have shown promising future accordingly. Prevailing evidence has shown that activating Nrf2/ARE and downstream antioxidant enzymes, as well as inhibiting Keap1 could play hopeful roles in overcoming AD. The current review highlights the neuroprotective effects of plant secondary metabolites through targeting Nrf2/Keap1/ARE and downstream interconnected mediators in combating AD.

Loss of Collapsin Response Mediator Protein 4 Attenuates 6-Hydroxydopamine-Induced Impairments in a Mouse Model of Parkinson's Disease

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by impaired motor symptoms induced by the degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNc). Many factors are speculated to operate in the mechanism of PD, including oxidative stress, mitochondrial dysfunction, abnormal protein handling, and PD induced apoptosis. Besides, researchers have recently shown that inflammatory secretions may engage neighboring cells such as astrocytes, which then induce autocrine and paracrine responses that amplify the inflammation, leading to neurodegeneration. In the present study, we analyzed the neuroprotective and anti-inflammatory effects of collapsin response mediator protein 4 (CRMP4) deletion in 6-hydroxydopamine (6-OHDA)-injected male mice, as well as its effects on motor impairments. Our findings indicated that the deletion of CRMP4 could maintain the TH-positive fibers in the striatum and the TH-positive cells in SNc, attenuate the inflammatory responses, and improve motor coordination and rotational behavior. Furthermore, based on our findings at the early time points, we hypothesized that primary differences between the Crmp4+/+ and Crmp4-/- mice may occur in microglia instead of neurons. Although further work should be carried out to clarify the specific role of CRMP4 in the pathogenesis of PD, our findings suggest that it could be a possible target for the treatment of PD.

Memory-Enhancing Effects of Origanum majorana Essential Oil in an Alzheimer's Amyloid beta1-42 Rat Model: A Molecular and Behavioral Study

Origanum L. (Lamiaceae) is an important genus of medicinal and aromatic plants used in traditional medicine since ancient times as culinary herbs and remedies. The aim of the present study was to evaluate the chemical composition, as well as the biochemical and cellular activities of freshly prepared Origanum majorana L. essential oil (OmEO) in an Alzheimer’s disease (AD) amyloid beta1-42 (Aβ1-42) rat model. OmEO (1% and 3%) was inhaled for 21 consecutive days, while Aβ1-42 was administered intracerebroventricularly to induce AD-like symptoms. Our data demonstrate that OmEO increased antioxidant activity and enhanced brain-derived neurotrophic factor (BDNF) expression, which in concert contributed to the improvement of cognitive function of animals. Moreover, OmEO presented beneficial effects on memory performance in Y-maze and radial arm-maze tests in the Aβ1-42 rat AD model.