The neuroprotective effects of fisetin, a natural flavonoid in neurodegenerative diseases: Focus on the role of oxidative stress

Oxidative stress-induced neurotoxicity of quantum dots and influencing factors

Quantum dots (QDs) have significant potential for treating and diagnosing CNS diseases. Meanwhile, the neurotoxicity of QDs has garnered attention. In this review, we focus on elucidating the mechanisms and consequences of CNS oxidative stress induced by QDs. First, we discussed the pathway of QDs transit into the brain. We then elucidate the relationship between QDs and oxidative stress from in vivo and in vitro studies. Furthermore, the main reasons and adverse outcomes of QDs leading to oxidative stress are discussed. In addition, the primary factors that may affect the neurotoxicity of QDs are analyzed. Finally, we propose potential strategies for mitigating QDs neurotoxicity and outline future perspectives for their development.

Exploring the effects of Dasatinib, Quercetin, and Fisetin on DNA methylation clocks: a longitudinal study on senolytic interventions

Senolytics, small molecules targeting cellular senescence, have emerged as potential therapeutics to enhance health span. However, their impact on epigenetic age remains unstudied. This study aimed to assess the effects of Dasatinib and Quercetin (DQ) senolytic treatment on DNA methylation (DNAm), epigenetic age, and immune cell subsets. In a Phase I pilot study, 19 participants received DQ for 6 months, with DNAm measured at baseline, 3 months, and 6 months. Significant increases in epigenetic age acceleration were observed in first-generation epigenetic clocks and mitotic clocks at 3 and 6 months, along with a notable decrease in telomere length. However, no significant differences were observed in second and third-generation clocks. Building upon these findings, a subsequent investigation evaluated the combination of DQ with Fisetin (DQF), a well-known antioxidant and antiaging senolytic molecule. After one year, 19 participants (including 10 from the initial study) received DQF for 6 months, with DNAm assessed at baseline and 6 months. Remarkably, the addition of Fisetin to the treatment resulted in non-significant increases in epigenetic age acceleration, suggesting a potential mitigating effect of Fisetin on the impact of DQ on epigenetic aging. Furthermore, our analyses unveiled notable differences in immune cell proportions between the DQ and DQF treatment groups, providing a biological basis for the divergent patterns observed in the evolution of epigenetic clocks. These findings warrant further research to validate and comprehensively understand the implications of these combined interventions.

A plant flavonol and genetic suppressors rescue a pathogenic mutation associated with kinesin in neurons

KIF1A, a microtubule-based motor protein responsible for axonal transport, is linked to a group of neurological disorders known as KIF1A-associated neurological disorder (KAND). Current therapeutic options for KAND are limited. Here, we introduced the clinically relevant KIF1A(R11Q) variant into the Caenorhabditis elegans homolog UNC-104, resulting in uncoordinated animal behaviors. Through genetic suppressor screens, we identified intragenic mutations in UNC-104's motor domain that rescued synaptic vesicle localization and coordinated movement. We showed that two suppressor mutations partially recovered motor activity in vitro by counteracting the structural defect caused by R11Q at KIF1A's nucleotide-binding pocket. We found that supplementation with fisetin, a plant flavonol, improved KIF1A(R11Q) worms' movement and morphology. Notably, our biochemical and single-molecule assays revealed that fisetin directly restored the ATPase activity and processive movement of human KIF1A(R11Q) without affecting wild-type KIF1A. These findings suggest fisetin as a potential intervention for enhancing KIF1A(R11Q) activity and alleviating associated defects in KAND.

Astaxanthin Inhibits H2O2-Induced Excessive Mitophagy and Apoptosis in SH-SY5Y Cells by Regulation of Akt/mTOR Activation

Oxidative stress, which damages cellular components and causes mitochondrial dysfunction, occurs in a variety of human diseases, including neurological disorders. The clearance of damaged mitochondria via mitophagy maintains the normal function of mitochondria and facilitates cell survival. Astaxanthin is an antioxidant known to have neuroprotective effects, but the underlying mechanisms remain unclear. This study demonstrated that astaxanthin inhibited H2O2-induced apoptosis in SH-SY5Y cells by ameliorating mitochondrial damage and enhancing cell survival. H2O2 treatment significantly reduced the levels of activated Akt and mTOR and induced mitophagy, while pretreatment with astaxanthin prevented H2O2-induced inhibition of Akt and mTOR and attenuated H2O2-induced mitophagy. Moreover, the inhibition of Akt attenuated the protective effect of astaxanthin against H2O2-induced cytotoxicity. Taken together, astaxanthin might inhibit H2O2-induced apoptosis by protecting mitochondrial function and reducing mitophagy. The results also indicate that the Akt/mTOR signaling pathway was critical for the protection of astaxanthin against H2O2-induced cytotoxicity. The results from the present study suggest that astaxanthin can reduce neuronal oxidative injury and may have the potential to be used for preventing neurotoxicity associated with neurodegenerative diseases.

Pathogenesis of Neurodegenerative Diseases and the Protective Role of Natural Bioactive Components

Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.

A Fisetin Delivery System for Neuroprotection: A Co-Amorphous Dispersion Prepared in Supercritical Carbon Dioxide

Fisetin (FIS), a senolytic flavonoid, mitigates age-related neuroprotective changes. An amorphous FIS dispersion with a co-carrier was prepared using supercritical fluid extraction with carbon dioxide (scCO2). Characterisation, including powder X-ray diffraction and Fourier-transform infrared spectroscopy, confirmed amorphization and assessed intermolecular interactions. The amorphous FIS dispersion exhibited enhanced solubility, dissolution profiles, and bioavailability compared to the crystalline form. In vitro, the amorphous FIS dispersion demonstrated antioxidant activity (the ABTS, CUPRAC, DDPH, FRAP assays) and neuroprotective effects by inhibiting acetylcholinesterase and butyrylcholinesterase. FIS modulated gut microbiota, reducing potentially pathogenic gram-negative bacteria without affecting probiotic microflora. These improvements in solubility, antioxidant and neuroprotective activities, and gut microbiome modulation suggest the potential for optimising FIS delivery systems to leverage its health-promoting properties while addressing oral functionality limitations.

Application potential of senolytics in clinical treatment

Of the factors studied in individual ageing, the accumulation of senescent cells has been considered as an essential cause of organ degeneration to eventually initiate age-related diseases. Cellular senescence is attributed to the accumulation of damage for an inducement in the activation of cell cycle inhibitory pathways, resulting the cell permanently withdraw from the cell proliferation cycle. Further, senescent cells will activate the inflammatory factor secretion pathway to promote the development of various age-related diseases. Senolytics, a small molecule compound, can delay disease development and extend mammalian lifespan. The evidence from multiple trials shows that the targeted killing of senescent cells has a significant clinical application for the treatment of age-related diseases. In addition, senolytics are also significant for the development of ageing research in solid organ transplantation, which can fully develop the potential of elderly organs and reduce the age gap between demand and supply. We conclude that the main characteristics of cellular senescence, the anti-ageing drug senolytics in the treatment of chronic diseases and organ transplantation, and the latest clinical progress of related researches in order to provide a theoretical basis for the prevention and treatment of ageing and related diseases.

Natural Sirtuin1 Activators and Atherosclerosis: an Overview

PURPOSE OF REVIEW

The purpose of this review is to summarize the most recent findings investigating the impact of several natural sirtuin (SIRT) activators, particularly SIRT1, on atherosclerosis.

RECENT FINDINGS

Sirtuins that belong to a family of class III histone deacetylases are believed to be novel therapeutic targets to treat age-related and chronic diseases. SIRT expression is regulated by small molecules called SIRT-activating compounds that can be found in natural food products. SIRT1 may exert protective effects in atherosclerosis, which is said to be a major cause of cardiovascular diseases. Most of the evidence supporting the beneficial effects of these natural compounds comes from in vitro or animal-based studies, while there have been particularly few or inconsistent human-based studies evaluating their long-term impact in recent years. SIRT1 activation has been demonstrated to mitigate or prevent atherosclerosis through various mechanisms. However, further research is required to determine the optimal SIRT activator dosage and to establish a stronger correlation between health effects and the administration of bioactive compounds. Additionally, conducting more human clinical trials is necessary to ensure the safety of these compounds for preventing atherosclerosis development.

Advances in Neuropathic Pain Research: Selected Intracellular Factors as Potential Targets for Multidirectional Analgesics

Neuropathic pain is a complex and debilitating condition that affects millions of people worldwide. Unlike acute pain, which is short-term and starts suddenly in response to an injury, neuropathic pain arises from somatosensory nervous system damage or disease, is usually chronic, and makes every day functioning difficult, substantially reducing quality of life. The main reason for the lack of effective pharmacotherapies for neuropathic pain is its diverse etiology and the complex, still poorly understood, pathophysiological mechanism of its progression. Numerous experimental studies, including ours, conducted over the last several decades have shown that the development of neuropathic pain is based on disturbances in cell activity, imbalances in the production of pronociceptive factors, and changes in signaling pathways such as p38MAPK, ERK, JNK, NF-κB, PI3K, and NRF2, which could become important targets for pharmacotherapy in the future. Despite the availability of many different analgesics, relieving neuropathic pain is still extremely difficult and requires a multidirectional, individual approach. We would like to point out that an increasing amount of data indicates that nonselective compounds directed at more than one molecular target exert promising analgesic effects. In our review, we characterize four substances (minocycline, astaxanthin, fisetin, and peimine) with analgesic properties that result from a wide spectrum of actions, including the modulation of MAPKs and other factors. We would like to draw attention to these selected substances since, in preclinical studies, they show suitable analgesic properties in models of neuropathy of various etiologies, and, importantly, some are already used as dietary supplements; for example, astaxanthin and fisetin protect against oxidative stress and have anti-inflammatory properties. It is worth emphasizing that the results of behavioral tests also indicate their usefulness when combined with opioids, the effectiveness of which decreases when neuropathy develops. Moreover, these substances appear to have additional, beneficial properties for the treatment of diseases that frequently co-occur with neuropathic pain. Therefore, these substances provide hope for the development of modern pharmacological tools to not only treat symptoms but also restore the proper functioning of the human body.

The Neuroprotective Role of Fisetin in Different Neurological Diseases: a Systematic Review

Neurological diseases place a substantial burden on public health and have a serious impact on the quality of life of patients. Despite the multifaceted pathological process involved in the occurrence and development of these neurological diseases, each disease has its own unique pathological characteristics and underlying molecular mechanisms which trigger their onset. Thus, it is unlikely to achieve effective treatment of neurological diseases by means of a single approach. To this end, we reason that it is pivotal to seek an efficient strategy that implements multitherapeutic targeting and addresses the multifaceted pathological process to overcome the complex issues related to neural dysfunction. In recent years, natural medicinal plant-derived monomers have received extensive attention as new neuroprotective agents for treatment of neurological disorders. Fisetin, a flavonoid, has emerged as a novel potential molecule that enhances neural protection and reverses cognitive abnormalities. The neuroprotective effects of fisetin are attributed to its multifaceted biological activity and multiple therapeutic mechanisms associated with different neurological disorders. In this review article, we summarize recent research progression regarding the pharmacological effects of fisetin in treating several neurological diseases and the potential mechanisms.

An Overview of Recent Advances in the Neuroprotective Potentials of Fisetin against Diverse Insults in Neurological Diseases and the Underlying Signaling Pathways

The nervous system plays a leading role in the regulation of physiological functions and activities in the body. However, a variety of diseases related to the nervous system have a serious impact on human health. It is increasingly clear that neurological diseases are multifactorial pathological processes involving multiple cellular systems, and the onset of these diseases usually involves a diverse array of molecular mechanisms. Unfortunately, no effective therapy exists to slow down the progression or prevent the development of diseases only through the regulation of a single factor. To this end, it is pivotal to seek an ideal therapeutic approach for challenging the complicated pathological process to achieve effective treatment. In recent years, fisetin, a kind of flavonoid widely existing in fruits, vegetables and other plants, has shown numerous interesting biological activities with clinical potentials including anti-inflammatory, antioxidant and neurotrophic effects. In addition, fisetin has been reported to have diverse pharmacological properties and neuroprotective potentials against various neurological diseases. The neuroprotective effects were ascribed to its unique biological properties and multiple clinical pharmacological activities associated with the treatment of different neurological disorders. In this review, we summarize recent research progress regarding the neuroprotective potential of fisetin and the underlying signaling pathways of the treatment of several neurological diseases.

The Neuroprotective Effects of Flavonoid Fisetin against Corticosterone-Induced Cell Death through Modulation of ERK, p38, and PI3K/Akt/FOXO3a-Dependent Pathways in PC12 Cells

The overactive hypothalamic-pituitary-adrenal (HPA) axis is believed to trigger the overproduction of corticosterone, leading to neurotoxicity in the brain. Fisetin is a flavonoid commonly found in fruits and vegetables. It has been suggested to possess various biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects. This study aims to explore the potential neuroprotective properties of fisetin against corticosterone-induced cell death and its underlying molecular mechanism in PC12 cells. Our results indicate that fisetin, at concentrations ranging from 5 to 40 μM, significantly protected PC12 cells against corticosterone-induced cell death. Fisetin effectively reduced the corticosterone-mediated generation of reactive oxygen species (ROS) in PC12 cells. Fisetin treatments also showed potential in inhibiting the corticosterone-induced apoptosis of PC12 cells. Moreover, inhibitors targeting MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK, and phosphatidylinositol 3-kinase (PI3K) were found to significantly block the increase in cell viability induced by fisetin in corticosterone-treated cells. Consistently, fisetin enhanced the phosphorylation levels of ERK, p38, Akt, and c-AMP response element-binding protein (CREB) in PC12 cells. Additionally, it was found that the diminished levels of p-CREB and p-ERK by corticosterone can be restored by fisetin treatment. Furthermore, the investigation of crosstalk between ERK and CREB revealed that p-CREB activation by fisetin occurred through the ERK-independent pathway. Moreover, we demonstrated that fisetin effectively counteracted the corticosterone-induced nuclear accumulation of FOXO3a, an apoptosis-triggering transcription factor, and concurrently promoted FOXO3a phosphorylation and its subsequent cytoplasmic localization through the PI3K/Akt pathway. In conclusion, our findings indicate that fisetin exerts its neuroprotective effect against corticosterone-induced cell death by modulating ERK, p38, and the PI3K/Akt/FOXO3a-dependent pathways in PC12 cells. Fisetin emerges as a promising phytochemical for neuroprotection.

Biological effects and mechanisms of fisetin in cancer: a promising anti-cancer agent

Fisetin, a natural flavonoid, possesses numerous biological activities that have been extensively studied in various diseases. When it comes to cancer, fisetin exhibits a range of biological effects, such as suppressing cell growth, triggering programmed cell death, reducing the formation of new blood vessels, protecting against oxidative stress, and inhibiting cell migration. Moreover, fisetin has the ability to enhance the effectiveness of chemotherapy. The anticancer properties of fisetin can be attributed to a diverse array of molecules and signaling pathways, including vascular endothelial growth factor (VEGF), mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), PI3K/Akt/mTOR, and Nrf2/HO-1. Consequently, fisetin holds promise as a therapeutic agent for anticancer treatment. In this review, we place emphasis on the biological functions and various molecular targets of fisetin in anticancer therapy.

Underlying Mechanisms of Brain Aging and Neurodegenerative Diseases as Potential Targets for Preventive or Therapeutic Strategies Using Phytochemicals

During aging, several tissues and biological systems undergo a progressive decline in function, leading to age-associated diseases such as neurodegenerative, inflammatory, metabolic, and cardiovascular diseases and cancer. In this review, we focus on the molecular underpinning of senescence and neurodegeneration related to age-associated brain diseases, in particular, Alzheimer's and Parkinson's diseases, along with introducing nutrients or phytochemicals that modulate age-associated molecular dysfunctions, potentially offering preventive or therapeutic benefits. Based on current knowledge, the dysregulation of microglia genes and neuroinflammation, telomere attrition, neuronal stem cell degradation, vascular system dysfunction, reactive oxygen species, loss of chromosome X inactivation in females, and gut microbiome dysbiosis have been seen to play pivotal roles in neurodegeneration in an interactive manner. There are several phytochemicals (e.g., curcumin, EGCG, fucoidan, galangin, astin C, apigenin, resveratrol, phytic acid, acacetin, daucosterol, silibinin, sulforaphane, withaferin A, and betulinic acid) that modulate the dysfunction of one or several key genes (e.g., TREM2, C3, C3aR1, TNFA, NF-kb, TGFB1&2, SIRT1&6, HMGB1, and STING) affected in the aged brain. Although phytochemicals have shown promise in slowing down the progression of age-related brain diseases, more studies to identify their efficacy, alone or in combinations, in preclinical systems can help to design novel nutritional strategies for the management of neurodegenerative diseases in humans.

Neurodegenerative Proteinopathies Induced by Environmental Pollutants: Heat Shock Proteins and Proteasome as Promising Therapeutic Tools

Environmental pollutants' (EPs) amount and diversity have increased in recent years due to anthropogenic activity. Several neurodegenerative diseases (NDs) are theorized to be related to EPs, as their incidence has increased in a similar way to human EPs exposure and they reproduce the main ND hallmarks. EPs induce several neurotoxic effects, including accumulation and gradual deposition of misfolded toxic proteins, producing neuronal malfunction and cell death. Cells possess different mechanisms to eliminate these toxic proteins, including heat shock proteins (HSPs) and the proteasome system. The accumulation and deleterious effects of toxic proteins are induced through HSPs and disruption of proteasome proteins' homeostatic function by exposure to EPs. A therapeutic approach has been proposed to reduce accumulation of toxic proteins through treatment with recombinant HSPs/proteasome or the use of compounds that increase their expression or activity. Our aim is to review the current literature on NDs related to EP exposure and their relationship with the disruption of the proteasome system and HSPs, as well as to discuss the toxic effects of dysfunction of HSPs and proteasome and the contradictory effects described in the literature. Lastly, we cover the therapeutic use of developed drugs and recombinant proteasome/HSPs to eliminate toxic proteins and prevent/treat EP-induced neurodegeneration.

Targeting Protein Aggregates with Natural Products: An Optional Strategy for Neurodegenerative Diseases

Protein aggregation is one of the hallmarks of aging and aging-related diseases, especially for the neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and others. In these diseases, many pathogenic proteins, such as amyloid-β, tau, α-Syn, Htt, and FUS, form aggregates that disrupt the normal physiological function of cells and lead to associated neuronal lesions. Protein aggregates in NDs are widely recognized as one of the important targets for the treatment of these diseases. Natural products, with their diverse biological activities and rich medical history, represent a great treasure trove for the development of therapeutic strategies to combat disease. A number of in vitro and in vivo studies have shown that natural products, by virtue of their complex molecular scaffolds that specifically bind to pathogenic proteins and their aggregates, can inhibit the formation of aggregates, disrupt the structure of aggregates and destabilize them, thereby alleviating conditions associated with NDs. Here, we systematically reviewed studies using natural products to improve disease-related symptoms by reducing or inhibiting the formation of five pathogenic protein aggregates associated with NDs. This information should provide valuable insights into new directions and ideas for the treatment of neurodegenerative diseases.

Therapeutic Potential of Polyphenols and Other Micronutrients of Marine Origin

Polyphenols are compounds found in various plants and foods, known for their antioxidant and anti-inflammatory properties. Recently, researchers have been exploring the therapeutic potential of marine polyphenols and other minor nutrients that are found in algae, fish and crustaceans. These compounds have unique chemical structures and exhibit diverse biological properties, including anti-inflammatory, antioxidant, antimicrobial and antitumor action. Due to these properties, marine polyphenols are being investigated as possible therapeutic agents for the treatment of a wide variety of conditions, such as cardiovascular disease, diabetes, neurodegenerative diseases and cancer. This review focuses on the therapeutic potential of marine polyphenols and their applications in human health, and also, in marine phenolic classes, the extraction methods, purification techniques and future applications of marine phenolic compounds.

Inflammaging, cellular senescence, and cognitive aging after traumatic brain injury

Traumatic brain injury (TBI) is associated with mortality and morbidity worldwide. Accumulating pre-clinical and clinical data suggests TBI is the leading extrinsic cause of progressive neurodegeneration. Neurological deterioration after either a single moderate-severe TBI or repetitive mild TBI often resembles dementia in aged populations; however, no currently approved therapies adequately mitigate neurodegeneration. Inflammation correlates with neurodegenerative changes and cognitive dysfunction for years post-TBI, suggesting a potential association between immune activation and both age- and TBI-induced cognitive decline. Inflammaging, a chronic, low-grade sterile inflammation associated with natural aging, promotes cognitive decline. Cellular senescence and the subsequent development of a senescence associated secretory phenotype (SASP) promotes inflammaging and cognitive aging, although the functional association between senescent cells and neurodegeneration is poorly defined after TBI. In this mini-review, we provide an overview of the pre-clinical and clinical evidence linking cellular senescence with poor TBI outcomes. We also discuss the current knowledge and future potential for senotherapeutics, including senolytics and senomorphics, which kill and/or modulate senescent cells, as potential therapeutics after TBI.

Flavonols in Action: Targeting Oxidative Stress and Neuroinflammation in Major Depressive Disorder

Major depressive disorder is one of the most common mental illnesses that highly impairs quality of life. Pharmacological interventions are mainly focused on altered monoamine neurotransmission, which is considered the primary event underlying the disease's etiology. However, many other neuropathological mechanisms that contribute to the disease's progression and clinical symptoms have been identified. These include oxidative stress, neuroinflammation, hippocampal atrophy, reduced synaptic plasticity and neurogenesis, the depletion of neurotrophic factors, and the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. Current therapeutic options are often unsatisfactory and associated with adverse effects. This review highlights the most relevant findings concerning the role of flavonols, a ubiquitous class of flavonoids in the human diet, as potential antidepressant agents. In general, flavonols are considered to be both an effective and safe therapeutic option in the management of depression, which is largely based on their prominent antioxidative and anti-inflammatory effects. Moreover, preclinical studies have provided evidence that they are capable of restoring the neuroendocrine control of the HPA axis, promoting neurogenesis, and alleviating depressive-like behavior. Although these findings are promising, they are still far from being implemented in clinical practice. Hence, further studies are needed to more comprehensively evaluate the potential of flavonols with respect to the improvement of clinical signs of depression.

Gut Microbiota in Autophagy Regulation: New Therapeutic Perspective in Neurodegeneration

Gut microbiota and the brain are related via a complex bidirectional interconnective network. Thus, intestinal homeostasis is a crucial factor for the brain, as it can control the environment of the central nervous system and play a significant role in disease progression. The link between neuropsychological behavior or neurodegeneration and gut dysbiosis is well established, but many involved pathways remain unknown. Accumulating studies showed that metabolites derived from gut microbiota are involved in the autophagy activation of various organs, including the brain, one of the major pathways of the protein clearance system that is essential for protein aggregate clearance. On the other hand, some metabolites are evidenced to disrupt the autophagy process, which can be a modulator of neurodegeneration. However, the detailed mechanism of autophagy regulation by gut microbiota remains elusive, and little research only focused on that. Here we tried to evaluate the crosstalk between gut microbiota metabolites and impaired autophagy of the central nervous system in neurodegeneration and the key to future research regarding gut dysbiosis and compromised autophagy in neurodegenerative diseases.

Fisetin, a Natural Polyphenol, Ameliorates Endometriosis Modulating Mast Cells Derived NLRP-3 Inflammasome Pathway and Oxidative Stress

A chronic, painful, and inflammatory condition known as endometriosis is defined by the extra-uterine development of endometrial tissue. The aim of this study was to evaluate the beneficial effects of fisetin, a naturally occurring polyphenol that is frequently present in a variety of fruits and vegetables. Uterine fragments were injected intraperitoneally to cause endometriosis, and fisetin was given orally every day. At 14 days of treatment, laparotomy was performed, and the endometrial implants and peritoneal fluids were collected for histological, biochemical, and molecular analyses. Rats subjected to endometriosis presented important macroscopic and microscopic changes, increased mast cell (MC) infiltration, and fibrosis. Fisetin treatment reduced endometriotic implant area, diameter, and volumes, as well as histological alterations, neutrophil infiltration, cytokines release, the number of MCs together with the expression of chymase and tryptase, and diminished α smooth muscle actin (α-sma) and transforming growth factor beta (TGF β) expressions. In addition, fisetin was able to reduce markers of oxidative stress as well as nitrotyrosine and Poly ADP ribose expressions and increase apoptosis in endometrial lesions. In conclusion, fisetin could represent a new therapeutic strategy to control endometriosis perhaps by targeting the MC-derived NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway and oxidative stress.

Antidiabetic drug sitagliptin blocks cyclophosphamide cerebral neurotoxicity by activating Nrf2 and suppressing redox cycle imbalance, inflammatory iNOS/NO/NF-κB response and caspase-3/Bax activation in rats

Cyclophosphamide (CYP) is a classic DNA-interacting anticancer agent with broad application in chemotherapy. However, CYP cerebral neurotoxicity is a worrisome side effect for clinicians and patients. Strategies to mitigate the underlying oxidative inflammatory cascades and neuroapoptosis induced by CYP are urgently needed. Herein, we have repurposed an antidiabetic drug, sitagliptin (STG), for a possible abrogation of CYP-induced cerebral neurotoxicity in rats. Healthy rats were administered STG (20 mg/kg body weight) for 5 days prior to neurotoxicity induced by CYP (200 mg/kg body weight, ip) on day 5 only, and rats were sacrificed after 24 h post-CYP injection. CYP caused profound increases in the cerebral levels of nitric oxide (NO), acetylcholinesterase (AChE), malondialdehyde (MDA), interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), nuclear factor-kappaB (NF-κB), inducible nitric oxide synthase (iNOS), caspase-3 and Bax protein compared to the control. Furthermore, CYP markedly depressed the activities of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD), along with levels of reduced glutathione (GSH) and nuclear factor erythroid 2-related factor2 (Nrf2) compared to the control (p < 0.05). Interestingly, STG pretreatment inhibited the CYP-induced alterations in caspase-3, Bax, pro-inflammatory cytokines, NO, iNOS, AChE, NF-κB, and restored the cerebral antioxidant apparatus, including the Nrf2 and histopathological abrasions. Therefore, these findings show that STG could be repurposed to prevent CYP-induced cerebral toxicity in the brain.

Oxidative Stress and Antioxidants in Neurodegenerative Disorders

Neurodegenerative disorders constitute a substantial proportion of neurological diseases with significant public health importance. The pathophysiology of neurodegenerative diseases is characterized by a complex interplay of various general and disease-specific factors that lead to the end point of neuronal degeneration and loss, and the eventual clinical manifestations. Oxidative stress is the result of an imbalance between pro-oxidant species and antioxidant systems, characterized by an elevation in the levels of reactive oxygen and reactive nitrogen species, and a reduction in the levels of endogenous antioxidants. Recent studies have increasingly highlighted oxidative stress and associated mitochondrial dysfunction to be important players in the pathophysiologic processes involved in neurodegenerative conditions. In this article, we review the current knowledge of the general effects of oxidative stress on the central nervous system, the different specific routes by which oxidative stress influences the pathophysiologic processes involved in Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis and Huntington's disease, and how oxidative stress may be therapeutically reversed/mitigated in order to stall the pathological progression of these neurodegenerative disorders to bring about clinical benefits.

Pharmacological screening of silibinin for antischizophrenic activity along with its acute toxicity evaluation in experimental animals

Silibinin (SIL), a flavolignan extracted from the medicinal plant "silybum marianum (milk thistle)", has traditionally been used to treat liver disease. This phytochemical has displayed neuroprotective properties, its activity against schizophrenia is not elucidated. The present study was designed to evaluate the antipsychotic potential of silibinin and probe its toxic potential. The acute oral toxicity study was assessed as per OECD 425 guidelines. Animals were divided into two groups of female rats (n = 6): one group served as the normal control and the other group received a 2,000 mg/kg dose of SIL. We also evaluated the antipsychotic potential of SIL. To this end, animals were divided into six groups (n = 10) of mice for both the preventive and curative protocols. Group I (CMC 1 mL/kg) served as the normal control and received CMC 1 mL/kg; group II was the diseased group treated with ketamine (10 mg/kg) i.p; group III was the standard group treated with clozapine 1 mg/kg; groups IV, V, and VI served as the treatment groups, receiving SIL 50, 100, and 200 mg/kg, respectively, orally for both protocols. Improvement in positive symptoms of the disease was evaluated by stereotypy and hyperlocomotion, while negative symptoms (behavioral despair) were determined by a forced swim test and a tail suspension test in the mice models. The results suggested that the LD₅₀ of SIL was greater than 2,000 mg/kg. Moreover, SIL prevented and reversed ketamine-induced increase in stereotypy (p < 0.001) and behavioral despair in the forced swim and tail suspension tests (p < 0.001). Taken together, the findings suggest that silibinin is a safe drug with low toxicity which demonstrates significant antipsychotic activity against the positive and negative symptoms of schizophrenia.

Fisetin, a dietary flavonoid, increases the sensitivity of chemoresistant head and neck carcinoma cells to cisplatin possibly through HSP90AA1/IL-17 pathway

Cisplatin (DDP) resistance is a bottleneck in the treatment of head and neck cancer (HNC), leading to poor prognosis. Fisetin, a dietary flavonoid, has low toxicity and high antitumor activity with unclear mechanisms. We intended to predict the targets of fisetin for reversing DDP-resistance and further verify their expressions and roles. A network pharmacology approach was applied to explore the target genes. The hub genes were screened out and subjected to molecular docking and experimental verification (in vivo and in vitro). Thirty-two genes common to fisetin and DDP-resistance were screened, including three hub genes, namely HSP90AA1, PPIA, and PTPRS. Molecular docking suggested that fisetin and the candidate proteins could bind tightly. HSP90AA1 was identified as the key gene. Administration of fisetin increased the sensitivity of chemoresistant cells (Cal27/DDP and FaDu/DDP) to DDP, accompanied by the downregulation of HSP90AA1 and IL-17. HSP90AA1 silencing increases the sensitivity of DDP-resistant cells to DDP, which was mediated by IL-17. In summary, fisetin might inhibit the chemoresistance of HNC cells to DDP by targeting the HSP90AA1/IL-17 pathway. Several hub genes might be the targets of fisetin for reversing DDP-resistance in HNC cells and might also serve as prognostic factors and therapeutic targets for HNC.

Potential of natural flavonols and flavanones in the treatment of ulcerative colitis

Ulcerative colitis (UC) is an inflammatory bowel disease generally characterized by chronic, persistent, recurrent, and non-specific ulcers of the intestine. Its main clinical manifestations include abdominal pain, diarrhea, and bloody stools. This disease is difficult to cure and even carries the risk of canceration. It has been listed as a modern refractory disease by the World Health Organization. Though a large amount of drugs are available for the inhibition of UC, the conventional treatment such as aminosalicylic acids, glucocorticoids, immunosuppressors, and biological agents possess certain limitations and serious side effects. Therefore, it is urgently needed for safe and effective drugs of UC, and natural-derived flavonols and flavanones showed tremendous potential. The present study concentrated on the progress of natural-derived flavonols and flavanones from edible and pharmaceutical plants for the remedy of UC over the last two decades. The potential pharmaceutical of natural-derived flavonols and flavanones against UC were closely connected with the modulation of gut microflora, gut barrier function, inflammatory reactions, oxidative stress, and apoptosis. The excellent efficacy and safety of natural flavonols and flavanones make them prospective drug candidates for UC suppression.

A mechanistic review of pharmacological activities of homeopathic medicine licorice against neural diseases

The use of medicinal plants has grown in popularity in recent decades because, as natural ingredients, they have fewer adverse effects and are more effective than synthetic alternatives. As a small perennial herb, Glycyrrhiza glabra L. (Licorice) has been investigated for its therapeutic efficacy against neural disorders mainly ischemic stroke as well as the neurodegenerative diseases such as dementia and Alzheimer's disease, and Parkinson's disease which has been attributed to its HMGB inhibitory function, reactive oxygen scavenging and anti-inflammatory activity. The objective of current review is to review the evidence for the pharmacological effects of licorice and its vital active components on neurological disorders and the underlying signaling networks. We reviewed Papers published from 2000.1.1 up to 2 January 2023 in web of science, Google Scholar and PubMed data bases using key words including "Licorice," "Glycyrrhiza glabra L.," "Glycyrrhizic acid," "brain," "neurodegenerative disease," "Alzheimer's," and "Parkinson" were used to search in title/abstracts. Licorice extract and/or its active components can be used safely in therapeutic doses for optimizing the management of a multiple neurodegenerative disorders, and hampering the extent of neural tissue injury and neurologic deficits subsequent to cerebrovascular accidents.

Hyperglycemia-associated Alzheimer's-like symptoms and other behavioral effects attenuated by Plumeria obtusa L. Extract in alloxan-induced diabetic rats

Diabetes mellitus is a chronic metabolic complaint with numerous short- and long-term complications that harm a person's physical and psychological health. Plumeria obtusa L. is a traditional medicine used in the treatment of diabetes to reduce complications related to behavior. Plumeria is a genus with antipsychotic activities. The objective of this study was to examine the effects of a methanolic extract of Plumeria obtusa L. in the attenuation of diabetes, on symptoms of Alzheimer disease, and on other associated behavioral aspects. A single dose of alloxan was administered to an experimental group of rats to induce development of diabetes (150 mg/kg, intraperitoneal) and the rats were then administered selected doses of methanolic extract of Plumeria obtusa L. (Po.Cr) or glibenclamide (0.6 mg/kg) for 45 consecutive days. Behavioral effects were evaluated using three validated assays of anxiety-related behavior: the open field test, the light and dark test, and the elevated plus maze. Anti-depressant effects of Plumeria obtusa L. were evaluated using the forced swim test (FST) and memory and learning were assessed using the Morris water maze (MWM) task. Po.Cr was also evaluated for phytochemicals using total phenolic content (TPC), total flavonoid content (TFC), and high-performance liquid chromatography assays, and antioxidant capability was assessed through assays of DPPH radical scavenging, total oxidation capacity, and total reducing capacity. In the alloxan-induced model of diabetes, the administration of Po.Cr and glibenclamide for 45 days produced a marked decrease (p < 0.001) in hyperglycemia compared to control animals. Po.Cr treatment also resulted in improvement in indicators, such as body weight and lipid profile (p < 0.05), as well as restoration of normal levels of alanine transaminase (ALT) (p < 0.001), a biomarker of liver function. Diabetic rats presented more Alzheimer-like symptoms, with greater impairment of memory and learning, and increased anxiety and depression compared to non-diabetic normal rats, whereas treated diabetic rats showed significant improvements in memory and behavioral outcomes. These results demonstrate that Po.Cr reversed alloxan-induced hyperglycemia and ameliorated Alzheimer-related behavioral changes, which supports additional study and assessment of conventional use of the plant to treat diabetes and associated behavioral complications.

Appraisal of selected ethnomedicinal plants as alternative therapies against onychomycosis: Evaluation of synergy and time-kill kinetics

Introduction: This study aims at the biological profiling of Allium sativum, Zingiber officinale, Nigella sativa, Curcuma longa, Mentha piperita, Withania somnifera, Azadirachta indica, and Lawsonia inermis as alternatives against onychomycosis to combat the treatment challenges. Methods: An extract library of aqueous (DW), ethyl acetate (EA), and methanol (M) extracts was subjected to phytochemical and antioxidant colorimetric assays to gauge the ameliorating role of extracts against oxidative stress. RP-HPLC quantified therapeutically significant polyphenols. Antifungal potential (disc diffusion and broth dilution) against filamentous (dermatophytes and non-dermatophytes) and non-filamentous fungi (yeasts; Candida albicans), synergistic interactions (checkerboard method) with terbinafine and amphotericin-B against resistant clinical isolates of dermatophytes (Trichophyton rubrum and Trichophyton tonsurans) and non-dermatophytes (Aspergillus spp., Fusarium dimerum, and Rhizopus arrhizus), time-kill kinetics, and protein estimation (Bradford method) were performed to evaluate the potential of extracts against onychomycosis. Results: The highest total phenolic and flavonoid content along with noteworthy antioxidant capacity, reducing power, and a substantial radical scavenging activity was recorded for the extracts of Z. officinale. Significant polyphenolics quantified by RP-HPLC included rutin (35.71 ± 0.23 µg/mgE), gallic acid (50.17 ± 0.22 µg/mgE), catechin (93.04 ± 0.43 µg/mgE), syringic acid (55.63 ± 0.35 µg/mgE), emodin (246.32 ± 0.44 µg/mgE), luteolin (78.43 ± 0.18 µg/mgE), myricetin (29.44 ± 0.13 µg/mgE), and quercetin (97.45 ± 0.22 µg/mgE). Extracts presented prominent antifungal activity against dermatophytes and non-dermatophytes (MIC-31.25 μg/ml). The checkerboard method showed synergism with 4- and 8-fold reductions in the MICs of A. sativum, Z. officinale, M. piperita, L. inermis, and C. longa extracts and doses of amphotericin-B (Amp-B) and terbinafine (against non-dermatophytes and dermatophytes, respectively). Furthermore, the synergistic therapy showed a time-dependent decrease in fungal growth even after 9 and 12 h of treatment. The inhibition of fungal proteins was also observed to be higher with the treatment of synergistic combinations than with the extracts alone, along with the cell membrane damage caused by terbinafine and amp-B, thus making the resistant fungi incapable of subsisting. Conclusion: The extracts of A. sativum, Z. officinale, M. piperita, L. inermis, and C. longa have proven to be promising alternatives to combat oxidative stress, resistance, and other treatment challenges of onychomycosis.

Selective Structural Derivatization of Flavonoid Acetamides Significantly Impacts Their Bioavailability and Antioxidant Properties

Flavonoids show abundant favorable physicochemical and drug related properties, leading to substantial biological applications which are limited by undesirable properties such as poor solubility, high polarity, low bioavailability, and enzymatic degradations. Chemical modification with bioisosteres can be used to address some of these challenges. We report the synthesis and characterization of partial flavonoid acetamide derivatives from quercetin, apigenin and luteolin and the evaluation of their structure-activity relationships based on antioxidant, bioavailability, drug likeness, and toxicity properties. The sequential synthesis was achieved with 76.67-87.23% yield; the structures of the compounds were confirmed using ¹H & ¹³C NMR characterizations. The purity of each compound was determined by HPLC while the molecular weights were determined by mass spectrometry. The % bioavailability was determined using the dialysis tubing procedure and the values were in the range 15.97-38.12%. The antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and expressed as the IC₅₀ values which were in the range 31.52-198.41 µM. The drug likeness and the toxicity properties of compounds 4, 5, 7, 11 and 15 were predicted using computational tools and showed satisfactory results. A structure-activity relationship evaluation reveals that hydroxyl and methylene groups attached on the 2-phenylchromen-4-one structure of the flavonoid play a colossal role in the overall antioxidant and bioavailability properties. The improved bioavailability and excellent drug relevance and toxicity properties present flavonoid acetamide derivatives as prospective drug candidates for further evaluations.

Association of Polyphenols Consumption with Risk for Gestational Diabetes Mellitus and Preeclampsia: A Systematic Review and Meta-Analysis

Gestational Diabetes Mellitus (GDM) and preeclampsia (PE) affects 6-25% of pregnancies and are characterized by an imbalance in natural prooxidant/antioxidant mechanisms. Due to their antioxidant and anti-inflammatory properties, polyphenols consumption during the pregnancy might exert positive effects by preventing GDM and PE development. However, this association remains inconclusive. This systematic review and metanalysis is aimed to analyze the association between polyphenol-rich food consumption during pregnancy and the risk of GDM and PE. A systematic search in MEDLINE, EMBASE, and Web of Science (Clarivate Analytics, London, United Kingdom) for articles dated between 1 January 1980 and July 2022 was undertaken to identify randomized controlled trials and observational studies evaluating polyphenol-rich food consumption and the risk of GDM and PE. The Newcastle-Ottawa Scale was used to evaluate the quality of these included studies. Twelve studies were included, of which eight articles evaluated GDM and four studied PE. A total of 3785 women presented with GDM (2.33%). No association between polyphenol consumption and GDM was found (ES = 0.85, 95% CI 0.71-1.01). When total polyphenol intake was considered, a lower likelihood to develop GDM was noted (ES = 0.78, 95% CI 0.69-0.89). Furthermore, polyphenol consumption was not associated with PE development (ES = 0.90, 95% CI 0.57-1.41). In conclusion, for both outcomes, pooled analyses showed no association with polyphenol-rich food consumption during pregnancy. Therefore, association of polyphenol intake with a decreased risk of GDM and PE remains inconclusive.

In-Vitro, In-Vivo, Molecular Docking and ADMET Studies of 2-Substituted 3,7-Dihydroxy-4H-chromen-4-one for Oxidative Stress, Inflammation and Alzheimer's Disease

Plants' bioactives are well-known safe drugs for vital diseases. Flavones and Flavonoid-rich dietary supplements are known to exhibit neuroprotective potential. In this study, we isolated a flavone 2-(3,4-dimethoxyphenyl)-3,7-dihydroxy-4H-chromen-4-one from Notholirion thomsonianum and it was evaluated against various targets of the oxidative stress-related neurological disorders. The compound showed excellent acetyl and butyrylcholinesterase inhibitions in its profile, giving IC50 values of 1.37 and 0.95 μM, respectively. Similarly, in in-vitro MAO-B assay, our flavone exhibited an IC50 value of 0.14 μM in comparison to the standard safinamide (IC50 0.025 μM). In in-vitro anti-inflammatory assay, our isolated compound exhibited IC50 values of 7.09, 0.38 and 0.84 μM against COX-1, COX-2 and 5-LOX, respectively. The COX-2 selectivity (SI) of the compound was 18.70. The compound was found safe in animals and was very effective in carrageenan-induced inflammation. Due to the polar groups in the structure, a very excellent antioxidant profile was observed in both in-vitro and in-vivo models. The compound was docked into the target proteins of the respective activities and the binding energies confirmed the potency of our compound. Furthermore, absorption, distribution, metabolism, excretion, and toxicity (ADMET) results showed that the isolated flavone has a good GIT absorption ability and comes with no hepatic and cardiotoxicity. In addition, the skin sensitization test, in-vitro human cell line activation test (h-CLAT) and KeratinoSens have revealed that isolated flavone is not skin sensitive with a confidence score of 59.6% and 91.6%. Herein, we have isolated a natural flavone with an effective profile against Alzheimer's, inflammation and oxidative stress. The exploration of this natural flavone will provide a baseline for future research in the field of drug development.

Corin is regulated by circ-0012397/miR-200a-3p and inhibits the oxygen-glucose deprivation-induced apoptosis of SHSY5Y neuroblastoma cells

Background

As a type II transmembrane serine protease, corin plays a role in several important physiological and pathological processes. We conducted a bioinformatics analysis to explore the roles of both corin and circ-0012397/miR-200a-3p in ischemic stroke.

Methods

We established an in vitro model using oxygen-glucose deprivation (OGD)-induced SHSY5Y cells. The proliferation and apoptosis of SHSY5Y cells was determined using Cell Counting Kit-8 (CCK-8) and flow cytometry/Hoechst 33258 staining, respectively. The RNA and protein level was tested using Real Time Quantitative Polymerase Chain Reaction (RT-qPCR) and western blot, respectively. The regulatory relationship of corin and circ-0012397/miR-200a-3p were detected by dual-luciferase reporter assays.

Results

We found that OGD downregulated the expression of corin in a time-dependent manner; this change was inversely proportional to the rate of apoptosis of the SHSY5Y cells. Further, high expression levels of corin enhanced the proliferation of SHSY5Y cells and inhibited the apoptosis of SHSY5Y cells by downregulating the expression of cleaved caspase-3, B-cell lymphoma 2 (BCL-2)-associated death promoter, extracellular-regulated protein kinase (ERK), and protein 38 (p38), and upregulated the expression of Bcl-2. Further, the dual-luciferase reporter assays and RT-qPCR showed that corin expression was regulated by circ-0012397/miR-200a-3p. Corin expression was affected by changes in circ-0012397 and miR-200a-3p expression, which were overexpressed or inhibited. Further, corin exerted different regulatory effects on apoptosis signaling-related proteins, including AD Bcl-2, cleaved caspase-3, ERK, and p38, under different expression levels of circ-0012397 and miR-200a-3p.

Conclusions

Corin promotes the cell proliferation and inhibits OGD-induced apoptosis of SHSY5Y cells, and that its expression is regulated by circ-0012397/miR-200a-3p. Thus, corin may be a potential target for ischemic stroke patients.