Momordica charantia polysaccharides could protect against cerebral ischemia/reperfusion injury through inhibiting oxidative stress mediated c-Jun N-terminal kinase 3 signaling pathway

Maintaining moderate levels of hypochlorous acid promotes neural stem cell proliferation and differentiation in the recovery phase of stroke

JOURNAL/nrgr/04.03/01300535-202503000-00029/figure1/v/2024-06-17T092413Z/r/image-tiff It has been shown clinically that continuous removal of ischemia/reperfusion-induced reactive oxygen species is not conducive to the recovery of late stroke. Indeed, previous studies have shown that excessive increases in hypochlorous acid after stroke can cause severe damage to brain tissue. Our previous studies have found that a small amount of hypochlorous acid still exists in the later stage of stroke, but its specific role and mechanism are currently unclear. To simulate stroke in vivo, a middle cerebral artery occlusion rat model was established, with an oxygen-glucose deprivation/reoxygenation model established in vitro to mimic stroke. We found that in the early stage (within 24 hours) of ischemic stroke, neutrophils produced a large amount of hypochlorous acid, while in the recovery phase (10 days after stroke), microglia were activated and produced a small amount of hypochlorous acid. Further, in acute stroke in rats, hypochlorous acid production was prevented using a hypochlorous acid scavenger, taurine, or myeloperoxidase inhibitor, 4-aminobenzoic acid hydrazide. Our results showed that high levels of hypochlorous acid (200 μM) induced neuronal apoptosis after oxygen/glucose deprivation/reoxygenation. However, in the recovery phase of the middle cerebral artery occlusion model, a moderate level of hypochlorous acid promoted the proliferation and differentiation of neural stem cells into neurons and astrocytes. This suggests that hypochlorous acid plays different roles at different phases of cerebral ischemia/reperfusion injury. Lower levels of hypochlorous acid (5 and 100 μM) promoted nuclear translocation of β-catenin. By transfection of single-site mutation plasmids, we found that hypochlorous acid induced chlorination of the β-catenin tyrosine 30 residue, which promoted nuclear translocation. Altogether, our study indicates that maintaining low levels of hypochlorous acid plays a key role in the recovery of neurological function.

Remote Ischemic Postconditioning-Mediated Neuroprotection against Stroke by Promoting Ketone Body-Induced Ferroptosis Inhibition

Neuronal death resulting from ischemic stroke is the primary cause of adult mortality and disability, and effective neuroprotective agents for poststroke intervention are still lacking. Remote ischemic postconditioning (RIPostC) has demonstrated significant protective effects against ischemia in various organs; however, the specific mechanisms are not fully understood. This study investigated the potential neuroprotective mechanisms of RIPostC in the context of ischemic stroke. Using a rat model of middle cerebral artery occlusion, we found that RIPostC mitigated neurological damage, improved movement in the open-field test, and protected against neuronal apoptosis. In terms of energy metabolism, RIPostC enhanced ATP levels, suppressed lactate content, and increased the production of ketone bodies (KBs). In the ferroptosis assay, RIPostC protected against lipoperoxidation, reversed the reduction of glutathione peroxidase 4 (GPX4), and mitigated the excessive expression of long-chain acyl-CoA synthetase family member 4 (ACSL4). In oxygen-glucose deprivation/reoxygenation-treated HT22 cells, KBs maintained GPX4 levels, suppressed ACSL4 expression, and preserved the mitochondrial cristae number. However, the effect of KBs on the expression of GPX4, ACSL4, and the number of mitochondrial cristae was blocked by erastin. Moreover, both RIPostC and KBs reduced total iron and ferrous ion content by repressing iron transporters both in vitro and in vivo. In conclusion, KBs-induced mitigation of ferroptosis could represent a new therapeutic mechanism for RIPostC in treating stroke.

Extraction, structures, biological effects and potential mechanisms of Momordica charantia polysaccharides: A review

Momordica charantia L. is a kind of vegetable with medicinal value. As the main component of the vegetable, Momordica charantia polysaccharides (MCPs) mainly consist of galactose, galacturonic acid, xylose, rhamnose, mannose and the molecular weight range is 4.33 × 103-1.16 × 106 Da. MCPs have been found to have various biological activities in recent years, such as anti-oxidation, anti-diabetes, anti-brain injury, anti-obesity, immunomodulatory and anti-inflammation. In this review, we systematically summarized the extraction methods, structural characteristics and physicochemical properties of MCPs. Especially MCPs modulate gut microbiota and cause the alterations of metabolic products, which can regulate different signaling pathways and target gene expressions to exert various functions. Meanwhile, the potential structure-activity relationships of MCPs were analyzed to provide a scientific basis for better development or modification of MCPs. Future researches on MCPs should focus on industrial extraction and molecular mechanisms. In East Asia, Momordica charantia L. is used as both food and medicine. It is not clear whether MCP has its unique biological effects. Further study on the difference between MCPs and other food-derived polysaccharides will be helpful to the development and potential application of Momordica charantia L.

Extraction methods, multiple biological activities, and related mechanisms of Momordica charantia polysaccharide: A review

Momordica Charantia Polysaccharide (MCP) is a key bioactive compound derived from bitter melon fruit. This review summarizes the advancements in MCP research, including extraction techniques, biological activities, and mechanisms. MCP can be extracted using various methods, and has demonstrated hypoglycemic, antioxidant, anti-inflammatory, and immunoregulatory effects. Research suggests that MCP may regulate metabolic enzymes, oxidative stress reactions, and inflammatory pathways. The review highlights the potential applications of MCP in areas such as anti-diabetes, antioxidant, anti-inflammatory, and immunoregulatory research. Future research should focus on elucidating the molecular mechanisms of MCP and optimizing extraction methods. This review provides a foundation for further research and utilization of MCP.

Unveiling the neuroprotective potential of dietary polysaccharides: a systematic review

Central nervous system (CNS) disorders present a growing and costly global health challenge, accounting for over 11% of the diseases burden in high-income countries. Despite current treatments, patients often experience persistent symptoms that significantly affect their quality of life. Dietary polysaccharides have garnered attention for their potential as interventions for CNS disorders due to their diverse mechanisms of action, including antioxidant, anti-inflammatory, and neuroprotective effects. Through an analysis of research articles published between January 5, 2013 and August 30, 2023, encompassing the intervention effects of dietary polysaccharides on Alzheimer's disease, Parkinson's disease, depression, anxiety disorders, autism spectrum disorder, epilepsy, and stroke, we have conducted a comprehensive review with the aim of elucidating the role and mechanisms of dietary polysaccharides in various CNS diseases, spanning neurodegenerative, psychiatric, neurodevelopmental disorders, and neurological dysfunctions. At least four categories of mechanistic bases are included in the dietary polysaccharides' intervention against CNS disease, which involves oxidative stress reduction, neuronal production, metabolic regulation, and gut barrier integrity. Notably, the ability of dietary polysaccharides to resist oxidation and modulate gut microbiota not only helps to curb the development of these diseases at an early stage, but also holds promise for the development of novel therapeutic agents for CNS diseases. In conclusion, this comprehensive review strives to advance therapeutic strategies for CNS disorders by elucidating the potential of dietary polysaccharides and advocating interdisciplinary collaboration to propel further research in this realm.

Bioactive polysaccharides from Momordica charantia as functional ingredients: a review of their extraction, bioactivities, structural-activity relationships, and application prospects

Momordica charantia L. is a well-known medicine and food homology plant with high pharmaceutical and nutritional values. Polysaccharides are carbohydrate polymers connected by glycosidic bonds, one of the key functional ingredients of M. charantia. Recently, M. charantia polysaccharides (MCPs) have attracted much attention from industries and researchers due to their anti-oxidant, anti-tumor, anti-diabetes, anti-bacteria, immunomodulatory, neuroprotection, and organ protection activities. However, the development and utilization of MCPs-based functional foods and medicines were hindered by the lack of a deeper understanding of the structure-activity relationship (SAR), structural modification, applications, and safety of MCPs. Herein, we provide an overview of the extraction, purification, structural characterization, bioactivities, and mechanisms of MCPs. Besides, SAR, toxicities, application, and influences of the modification associated with bioactivities are spotlighted, and the potential development and future study direction are scrutinized. This review provides knowledge and research underpinnings for the further research and application of MCPs as therapeutic agents and functional food additives.

Momordicine I suppresses glioma growth by promoting apoptosis and impairing mitochondrial oxidative phosphorylation

Glioblastoma (GBM) is the most common type of primary brain tumor. Patients with GBM have poor survival outcomes. Isolated components of Momordica charantia have anticancer effects. However, the bioactivity of M. charantia extracts against GBM remains unknown. We tested four major extracts of M. charantia and found that momordicine I reduced glioma cell viability without serious cytotoxic effects on astrocytes. Momordicine I suppressed glioma cell colony formation, proliferation, migration, and invasion. Momordicine I also induced apoptosis, intracellular reactive oxygen species (ROS) production, and senescence in glioma cells. Moreover, momordicine I decreased the oxidative phosphorylation capacity of glioma cells and inhibited tumor sphere formation in temozolomide (TMZ)-resistant GBM cells. We further explored whether the antiglioma effect of momordicine I may be related to cell cycle modulation and DLGPA5 expression. Our results indicate that the cytotoxic effect of momordicine I on glioma cells suggests its potential therapeutic application to GBM treatment. See also Figure 1(Fig. 1).

Phytochemical Profiles and Biological Studies of Selected Botanical Dietary Supplements Used in the United States

Based on their current wide bioavailability, botanical dietary supplements have become an important component of the United States healthcare system, although most of these products have limited scientific evidence for their use. The most recent American Botanical Council Market Report estimated for 2020 a 17.3% increase in sales of these products when compared to 2019, for a total sales volume of $11,261 billion. The use of botanical dietary supplements products in the United States is guided by the Dietary Supplement Health and Education Act (DSHEA) from 1994, enacted by the U.S. Congress with the aim of providing more information to consumers and to facilitate access to a larger number of botanical dietary supplements available on the market than previously. Botanical dietary supplements may be formulated for and use only using crude plant samples (e.g., plant parts such as the bark, leaves, or roots) that can be processed by grinding into a dried powder. Plant parts can also be extracted with hot water to form an "herbal tea." Other preparations of botanical dietary supplements include capsules, essential oils, gummies, powders, tablets, and tinctures. Overall, botanical dietary supplements contain bioactive secondary metabolites with diverse chemotypes that typically are found at low concentration levels. These bioactive constituents usually occur in combination with inactive molecules that may induce synergy and potentiation of the effects observed when botanical dietary supplements are taken in their different forms. Most of the botanical dietary supplements available on the U.S. market have been used previously as herbal remedies or as part of traditional medicine systems from around the world. Their prior use in these systems also provides a certain level of assurance in regard to lower toxicity levels. This chapter will focus on the importance and diversity of the chemical features of bioactive secondary metabolites found in botanical dietary supplements that are responsible for their applications. Many of the active principles of botanical dietary substances are phenolics and isoprenoids, but glycosides and some alkaloids are also present. Biological studies on the active constituents of selected botanical dietary supplements will be discussed. Thus, the present chapter should be of interest for both members of the natural products scientific community, who may be performing development studies of the products available, as well as for healthcare professionals who are directly involved in the analysis of botanical interactions and evaluation of the suitability of botanical dietary supplements for human consumption.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

Plant based food bioactives: A boon or bane for neurological disorders

Neurological disorders are the foremost occurring diseases across the globe resulting in progressive dysfunction, loss of neuronal structure ultimately cell death. Therefore, attention has been drawn toward the natural resources for the search of neuroprotective agents. Plant-based food bioactives have emerged as potential neuroprotective agents for the treatment of neurodegenerative disorders. This comprehensive review primarily focuses on various plant food bioactive, mechanisms, therapeutic targets, in vitro and in vivo studies in the treatment of neurological disorders to explore whether they are boon or bane for neurological disorders. In addition, the clinical perspective of plant food bioactives in neurological disorders are also highlighted. Scientific evidences point toward the enormous therapeutic efficacy of plant food bioactives in the prevention or treatment of neurological disorders. Nevertheless, identification of food bioactive components accountable for the neuroprotective effects, mechanism, clinical trials, and consolidation of information flow are warranted. Plant food bioactives primarily act by mediating through various pathways including oxidative stress, neuroinflammation, apoptosis, excitotoxicity, specific proteins, mitochondrial dysfunction, and reversing neurodegeneration and can be used for the prevention and therapy of neurodegenerative disorders. In conclusion, the plant based food bioactives are boon for neurological disorders.

Momordica charantia polysaccharide ameliorates D-galactose-induced aging through the Nrf2/β-Catenin signaling pathway

Aging is widely thought to be associated with oxidative stress. Momordica charantia (MC) is a classic vegetable and traditional herbal medicine widely consumed in Asia, and M. charantia polysaccharide (MCP) is the main bioactive ingredient of MC. We previously reported an antioxidative and neuroprotective effect of MCP in models of cerebral ischemia/reperfusion and hemorrhage injury. However, the role played by MCP in neurodegenerative diseases, especially during aging, remains unknown. In this study, we investigated the protective effect of MCP against oxidative stress and brain damage in a D-galactose-induced aging model (DGAM). The Morris water maze test was performed to evaluate the spatial memory function of model rats. The levels of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were measured and telomerase activity was determined. The results showed that MCP treatment attenuated spatial memory dysfunction induced by D-galactose. In addition, MCP increased antioxidant capacity by decreasing MDA and increasing SOD and GSH levels. MCP treatment also improved telomerase activity in aging rats. Mechanistically, MCP promoted the entry of both Nrf2 and β-Catenin into the nucleus, which is the hallmark of antioxidation signaling pathway activation. This study highlights a role played by MCP in ameliorating aging-induced oxidative stress injury and reversing the decline in learning and memory capacity. Our work provides evidence that MCP administration might be a potential antiaging strategy.

The mechanism of ferroptosis regulating oxidative stress in ischemic stroke and the regulation mechanism of natural pharmacological active components

Cerebrovascular diseases, such as ischemic stroke, pose serious medical challenges worldwide due to their high morbidity and mortality and limitations in clinical treatment strategies. Studies have shown that reactive oxygen species (ROS)-mediated inflammation, excitotoxicity, and programmed cell death of each neurovascular unit during post-stroke hypoxia and reperfusion play an important role in the pathological cascade. Ferroptosis, a programmed cell death characterized by iron-regulated accumulation of lipid peroxidation, is caused by abnormal metabolism of lipids, glutathione (GSH), and iron, and can accelerate acute central nervous system injury. Recent studies have gradually uncovered the pathological process of ferroptosis in the neurovascular unit of acute stroke. Some drugs such as iron chelators, ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1) can protect nerves after neurovascular unit injury in acute stroke by inhibiting ferroptosis. In addition, combined with our previous studies on ferroptosis mediated by natural compounds in ischemic stroke, this review summarized the progress in the regulation mechanism of natural chemical components and herbal chemical components on ferroptosis in recent years, in order to provide reference information for future research on ferroptosis and lead compounds for the development of ferroptosis inhibitors.

Natural Compounds for SIRT1-Mediated Oxidative Stress and Neuroinflammation in Stroke: A Potential Therapeutic Target in the Future

Stroke is a fatal cerebral vascular disease with a high mortality rate and substantial economic and social costs. ROS production and neuroinflammation have been implicated in both hemorrhagic and ischemic stroke and have the most critical effects on subsequent brain injury. SIRT1, a member of the sirtuin family, plays a crucial role in modulating a wide range of physiological processes, including apoptosis, DNA repair, inflammatory response, and oxidative stress. Targeting SIRT1 to reduce ROS and neuroinflammation might represent an emerging therapeutic target for stroke. Therefore, we conducted the present review to summarize the mechanisms of SIRT1-mediated oxidative stress and neuroinflammation in stroke. In addition, we provide a comprehensive introduction to the effect of compounds and natural drugs on SIRT1 signaling related to oxidative stress and neuroinflammation in stroke. We believe that our work will be helpful to further understand the critical role of the SIRT1 signaling pathway and will provide novel therapeutic potential for stroke treatment.

KAP1 phosphorylation promotes the survival of neural stem cells after ischemia/reperfusion by maintaining the stability of PCNA

Aims

To explore the function of phosphorylation of KAP1 (p-KAP1) at the serine-824 site (S824) in the proliferation and apoptosis of endogenous neural stem cells (NSCs) after cerebral ischemic/reperfusion (I/R).

Methods

The apoptosis and proliferation of C17.2 cells transfected with the p-KAP1-expression plasmids and the expression of proliferation cell nuclear antigen (PCNA) and p-KAP1 were detected by immunofluorescence and Western blotting after the Oxygen Glucose deprivation/reperfusion model (OGD/R). The interaction of p-KAP1 and CUL4A with PCNA was analyzed by immunoprecipitation. In the rats MCAO model, we performed the adeno-associated virus (AAV) 2/9 gene delivery of p-KAP1 mutants to verify the proliferation of endogenous NSCs and the colocalization of PCNA and CUL4A by immunofluorescence.

Results

The level of p-KAP1 was significantly down-regulated in the stroke model in vivo and in vitro. Simulated p-KAP1(S824) significantly increased the proliferation of C17.2 cells and the expression of PCNA after OGD/R. Simulated p-KAP1(S824) enhanced the binding of p-KAP1 and PCNA and decreased the interaction between PCNA and CUL4A in C17.2 cells subjected to OGD/R. The AAV2/9-mediated p-KAP1(S824) increased endogenous NSCs proliferation, PCNA expression, p-KAP1 binding to PCNA, and improved neurological function in the rat MCAO model.

Conclusions

Our findings confirmed that simulated p-KAP1(S824) improved the survival and proliferation of endogenous NSCs. The underlying mechanism is that highly expressed p-KAP1(S824) promotes binding to PCNA, and inhibits the binding of CUL4A to PCNA. This reduced CUL4A-mediated ubiquitination degradation to increase the stability of PCNA and promote the survival and proliferation of NSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02962-5.

Effects of Momordica charantia exosomes on platelet activation, adhesion, and aggregation

The platelets play a crucial role in the progression of multiple medical conditions, such as stroke and tumor metastasis, where antiplatelet therapy may be a boon for treating these diseases. In this study, we have attempted to study the effects of extracted Momordica charantia exosomes (MCEs) on platelet activation, adhesion, and aggregation. Adult platelets isolated from healthy individuals were dose-dependently treated with MCEs (0.1, 40, and 200 μg/ml). We performed flow cytometry to detect the expression of platelet activation protein marker-activated GP IIb/IIIa (PAC-1) and P-selectin (CD62P). Platelet adhesion was analyzed through fluorescence labeling assays. The effect of MCEs on platelet-mediated cell migration of HCT116 cells was observed by transwell. Furthermore, the MCAO model of Sprague-Dawley rats was used to observe the effect of MCEs (200, 400, and 800 μg/kg) on platelet aggregation and maximum thrombotic agglutination in vivo. The results showed that 200 μg/ml MCEs exerted the most pronounced effect on platelet activation, adhesion, and aggregation. Experiments on animals showed that MCEs significantly inhibited platelet aggregation and attenuated the maximum thrombus agglutination. We concluded that MCEs inhibited platelet activation, adhesion, aggregation, and platelet-mediated migration of HCT116 cells, indicating the potential role MCEs may play in the treatment of stroke and tumor metastasis.

Momordica charantia Exosome-Like Nanoparticles Exert Neuroprotective Effects Against Ischemic Brain Injury via Inhibiting Matrix Metalloproteinase 9 and Activating the AKT/GSK3β Signaling Pathway

Plant exosome-like nanoparticles (ELNs) have shown great potential in treating tumor and inflammatory diseases, but the neuroprotective effect of plant ELNs remains unknown. In the present study, we isolated and characterized novel ELNs from Momordica charantia (MC) and investigated their neuroprotective effects against cerebral ischemia-reperfusion injury. In the present study, MC-ELNs were isolated by ultracentrifugation and characterized. Male Sprague–Dawley rats were subjected to middle cerebral artery occlusion (MCAO) and MC-ELN injection intravenously. The integrity of the blood–brain barrier (BBB) was examined by Evans blue staining and with the expression of matrix metalloproteinase 9 (MMP-9), claudin-5, and ZO-1. Neuronal apoptosis was evaluated by TUNEL and the expression of apoptotic proteins including Bcl2, Bax, and cleaved caspase 3. The major discoveries include: 1) Dil-labeled MC-ELNs were identified in the infarct area; 2) MC-ELN treatment significantly ameliorated BBB disruption, decreased infarct sizes, and reduced neurological deficit scores; 3) MC-ELN treatment obviously downregulated the expression of MMP-9 and upregulated the expression of ZO-1 and claudin-5. Small RNA-sequencing revealed that MC-ELN-derived miRNA5266 reduced MMP-9 expression. Furthermore, MC-ELN treatment significantly upregulated the AKT/GSK3β signaling pathway and attenuated neuronal apoptosis in HT22 cells. Taken together, these findings indicate that MC-ELNs attenuate ischemia-reperfusion–induced damage to the BBB and inhibit neuronal apoptosis probably via the upregulation of the AKT/GSK3β signaling pathway.

A comprehensive review on bitter gourd (Momordica charantia L.) as a gold mine of functional bioactive components for therapeutic foods

Bitter gourd is a tropical wine grown mainly in India, China and South East Asia. The plant is cultivated mainly for its fruit part which is edible. Bitter gourd is unaccepted widely due to its bitter taste. Nevertheless, the fruit is a source of several key nutrients. The plant, as a whole contains, more than 60 phyto-medicines that are active against more than 30 diseases, including cancer and diabetes. Currently, the incorporation of the bioactive compounds isolated from bitter gourd into functional foods and beverages finds a new horizon. Nanoencapsulation and novel green extraction methods can be employed to improve the yield and quality of extracted compounds and their stability while incorporation into food products. The present review is an attempt to throw light to nutritional aspects, various bioactive compounds present and important nutraceutical properties of the bitter gourd plant in detail.

Graphical Abstract

Momordica. charantia-Derived Extracellular Vesicles-Like Nanovesicles Protect Cardiomyocytes Against Radiation Injury via Attenuating DNA Damage and Mitochondria Dysfunction

Thoracic radiotherapy patients have higher risks of developing radiation-induced heart disease (RIHD). Ionizing radiation generates excessive reactive oxygens species (ROS) causing oxidative stress, while Momordica. charantia and its extract have antioxidant activity. Plant-derived extracellular vesicles (EVs) is emerging as novel therapeutic agent. Therefore, we explored the protective effects of Momordica. charantia-derived EVs-like nanovesicles (MCELNs) against RIHD. Using density gradient centrifugation, we successfully isolated MCELNs with similar shape, size, and markers as EVs. Confocal imaging revealed that rat cardiomyocytes H9C2 cells internalized PKH67 labeled MCELNs time-dependently. In vitro assay identified that MCELNs promoted cell proliferation, suppressed cell apoptosis, and alleviated the DNA damage in irradiated (16 Gy, X-ray) H9C2 cells. Moreover, elevated mitochondria ROS in irradiated H9C2 cells were scavenged by MCELNs, protecting mitochondria function with re-balanced mitochondria membrane potential. Furthermore, the phosphorylation of ROS-related proteins was recovered with increased ratios of p-AKT/AKT and p-ERK/ERK in MCELNs treated irradiated H9C2 cells. Last, intraperitoneal administration of MCELNs mitigated myocardial injury and fibrosis in a thoracic radiation mice model. Our data demonstrated the potential protective effects of MCELNs against RIHD. The MCELNs shed light on preventive regime development for radiation-related toxicity.

Wild Bitter Melon Extract Abrogates Hypoxia-Induced Cell Death via the Regulation of Ferroptosis, ER Stress, and Apoptosis in Microglial BV2 Cells

Microglial cells are well-known phagocytic cells that are resistant to the central nervous system (CNS) and play an important role in the maintenance of CNS homeostasis. Activated microglial cells induce neuroinflammation under hypoxia and typically cause neuronal damage in CNS diseases. In this study, we propose that wild bitter melon extract (WBM) has a protective effect on hypoxia-induced cell death via regulation of ferroptosis, ER stress, and apoptosis. The results demonstrated that hypoxia caused microglial BV-2 the accumulation of lipid ROS, ferroptosis, ER stress, and apoptosis. In this study, we investigated the pharmacological effects of WBM on BV-2 cells following hypoxia-induced cell death. The results indicated that WBM reversed hypoxia-downregulated antiferroptotic molecules Gpx4 and SLC7A11, as well as upregulated the ER stress markers CHOP and Bip. Moreover, WBM alleviated hypoxia-induced apoptosis via the regulation of cleaved-caspase 3, Bax, and Bcl-2. Our results suggest that WBM may be a good candidate for preventing CNS disorders in the future.

Healthy Serum-Derived Exosomes Improve Neurological Outcomes and Protect Blood–Brain Barrier by Inhibiting Endothelial Cell Apoptosis and Reversing Autophagy-Mediated Tight Junction Protein Reduction in Rat Stroke Model

Blood–brain barrier (BBB) dysfunction causing edema and hemorrhagic transformation is one of the pathophysiological characteristics of stroke. Protection of BBB integrity has shown great potential in improving stroke outcome. Here, we assessed the efficacy of exosomes extracted from healthy rat serum in protection against ischemic stroke in vivo and in vitro. Exosomes were isolated by gradient centrifugation and ultracentrifugation and exosomes were characterized by transmission electron microscopy (TEM) and nanoparticle tracking video microscope. Exosomes were applied to middle cerebral artery occlusion (MCAO) rats or brain microvascular endothelial cell line (bEnd.3) subjected to oxygen-glucose deprivation (OGD) injury. Serum-derived exosomes were injected intravenously into adult male rats 2 h after transient MCAO. Infarct volume and gross cognitive function were assessed 24 h after reperfusion. Poststroke rats treated with serum-derived exosomes exhibited significantly reduced infarct volumes and enhanced neurological function. Apoptosis was assessed via terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining and the expression of B-cell lymphoma-2 (Bcl-2), Bax, and cleaved caspase-3 24 h after injury. Our data showed that serum exosomes treatment strikingly decreased TUNEL⁺ cells in the striatum, enhanced the ratio of Bcl-2 to Bax, and inhibited cleaved caspase-3 production in MCAO rats and OGD/reoxygenation insulted bEnd.3 cells. Under the consistent treatment, the expression of microtubule-associated protein 1 light chain 3B-II (LC3B-II), LC3B-I, and Sequestosome-1 (SQSTM1)/p62 was detected by Western blotting. Autolysosomes were observed via TEM. We found that serum exosomes reversed the ratio of LC3B-II to LC3B-I, prevented SQSTM1/p62 degradation, autolysosome formation, and autophagic flux. Together, these results indicated that exosomes isolated from healthy serum provided neuroprotection against experimental stroke partially via inhibition of endothelial cell apoptosis and autophagy-mediated BBB breakdown. Intravenous serum-derived exosome treatment may, therefore, provide a novel clinical therapeutic strategy for ischemic stroke.

AMPK activators for the prevention and treatment of neurodegenerative diseases

INTRODUCTION

As the global population ages at an unprecedented rate, the burden of neurodegenerative diseases is expected to grow. Given the profound impact illness like dementia exert on individuals and society writ large, researchers, physicians, and scientific organizations have called for increased investigation into their treatment and prevention. Both metformin and aspirin have been associated with improved cognitive outcomes. These agents are related in their ability to stimulate AMP kinase (AMPK). Momordica charantia, another AMPK activator, is a component of traditional medicines and a novel agent for the treatment of cancer. It is also being evaluated as a nootropic agent.

AREAS COVERED

This article is a comprehensive review which examines the role of AMPK activation in neuroprotection and the role that AMPK activators may have in the management of dementia and cognitive impairment. It evaluates the interaction of metformin, aspirin, and Momordica charantia, with AMPK, and reviews the literature characterizing these agents' impact on neurodegeneration.

EXPERT OPINION

We suggest that AMPK activators should be considered for the treatment and prevention of neurodegenerative diseases. We identify multiple areas of future investigation which may have a profound impact on patients worldwide.

Emerging Role of Ferroptosis in the Pathogenesis of Ischemic Stroke: A New Therapeutic Target?

Ischemic stroke is one of the main causes of high morbidity, mortality, and disability worldwide; however, the treatment methods are limited and do not always achieve satisfactory results. The pathogenesis of ischemic stroke is complex, defined by multiple mechanisms; among them, programmed death of neuronal cells plays a significant role. Ferroptosis is a novel type of regulated cell death characterized by iron redistribution or accumulation and increased lipid peroxidation in the membrane. Ferroptosis is implicated in many pathological conditions, such as cancer, neurodegenerative diseases, and ischemia-reperfusion injury. In this review, we summarize current research findings on ferroptosis, including possible molecular mechanisms and therapeutic applications of ferroptosis regulators, with a focus on the involvement of ferroptosis in the pathogenesis and treatment of ischemic stroke. Understanding the role of ferroptosis in ischemic stroke will throw some light on the development of methods for diagnosis, treatment, and prevention of this devastating disease.

TCD, a triterpenoid isolated from wild bitter gourd, reduces synaptosomal release of glutamate and protects against kainic acid-induced neuronal death

3β,7β,25-Trihydroxycucurbita-5,23(E)-dien-19-al (TCD) is a triterpenoid isolated from wild bitter gourd that is a common tropical vegetable with neuroprotective effects. Because excessive glutamate release is a major cause of neuronal damage in various neurological disorders, the aims of this study were to examine the effect of TCD on glutamate release in vitro and to examine the effect of TCD in vivo. In rat cerebrocortical synaptosomes, TCD reduced 4-aminopyridine (4-AP)-stimulated glutamate release and Ca2+ concentration elevation, but had no effect on plasma membrane potential. TCD-mediated inhibition of 4-AP-induced glutamate release was dependent on the presence of extracellular calcium; persisted in the presence of the glutamate transporter inhibitor dl-TBOA, P/Q-type Ca2+ channel blocker ω-agatoxin IVA, and intracellular Ca2+-releasing inhibitors dantrolene and CGP37157; and was blocked by the vesicular transporter inhibitor bafilomycin A1 and the N-type Ca2+ channel blocker ω-conotoxin GVIA. Molecular docking studies have demonstrated that TCD binds to N-type Ca2+ channels. TCD-mediated inhibition of 4-AP-induced glutamate release was abolished by the Ca2+-dependent protein kinase C (PKC) inhibitor Go6976, but was unaffected by the Ca2+-independent PKC inhibitor rottlerin. Furthermore, TCD considerably reduced the phosphorylation of PKC, PKCα, and myristoylated alanine-rich C kinase substrate, a major presynaptic substrate for PKC. In a rat model of kainic acid (KA)-induced excitotoxicity, TCD pretreatment substantially attenuated KA-induced neuronal death in the CA3 hippocampal region. These results suggest that TCD inhibits synaptosomal glutamate release by suppressing N-type Ca2+ channels and PKC activity and exerts protective effects against KA-induced excitotoxicity in vivo.

Momordica Charantia Polysaccharides Attenuates MPP+-Induced Injury in Parkinson’s Disease Mice and Cell Models by Regulating TLR4/MyD88/NF-κB Pathway

Objective. To investigate the potential role of Momordica charantia polysaccharides (MCPs) in Parkinson’s disease (PD) and reveal the molecular mechanism of its function. Method. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium (1-methyl-4-phenylpyridinium, MPP+) were used to establish PD mice and cell models. The mice and cells were divided into 4 groups: Control group, Control+MCPs group, PD group, and PD+MCPs group. Pole climbing experiment and Rotarod experiment were used to observe the coordination ability of mice. High-performance liquid chromatography and enzyme-linked immunosorbent assay (ELISA) were used to determine neurotransmitters and metabolites, inflammatory factors TNF-α and IL-1β, oxidative stress-related markers SOD, MDA, and GSH in striatum tissues. Western blot was used to determine the protein levels of tyrosine hydroxylase (TH), oxidative stress-related protein Cytochrome C (Cytochrome C), and apoptosis-related proteins Bcl-2, Bax, and cleaved Caspase-3 in tissues and cells. Moreover, flow cytometry, PI staining, and fluorescence were used to observe cell apoptosis. Finally, the activation effect of MCPs on TLR4/MyD88/NF-κB signaling pathway was observed and verified. Results. Compared with the Control group, MPTP treatment can induce brain damage in mice (all $P<0.05$ ), change the metabolic state of neurotransmitters (all $P<0.05$ ), induce inflammation (all $P<0.05$ ), and induce apoptosis and the occurrence of oxidation reaction (all $P<0.05$ ); however, MCPs treatment can significantly reverse the above changes (all $P<0.05$ ). In cell models, studies have found that MCPs can play a protective role by regulating the activation state of TLR4/MyD88/NF-κB pathway. Conclusion. This study found that the application of MCPs therapy can play anti-inflammatory, antioxidative stress, and antiapoptotic effects in PD by regulating the activation of the TLR4/MyD88/NF-κB pathway.

Danggui-Shaoyao-San (DSS) Ameliorates Cerebral Ischemia-Reperfusion Injury via Activating SIRT1 Signaling and Inhibiting NADPH Oxidases

Danggui-Shayao-San (DSS) is a famous Traditional Chinese Medicine formula that used for treating pain disorders and maintaining neurological health. Recent studies indicate that DSS has neuroprotective effects against ischemic brain damage but its underlining mechanisms remain unclear. Herein, we investigated the neuroprotective mechanisms of DSS for treating ischemic stroke. Adult male Sprague-Dawley (S.D.) rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus 22 h of reperfusion. Both ethanol extract and aqueous extract of DSS (12 g/kg) were orally administrated into the rats at 30 min prior to MCAO ischemic onset. We found that 1) ethanol extract of DSS, instead of aqueous extract, reduced infarct sizes and improved neurological deficit scores in the post-ischemic stroke rats; 2) Ethanol extract of DSS down-regulated the expression of the cleaved-caspase 3 and Bax, up-regulated bcl-2 and attenuated apoptotic cell death in the ischemic brains; 3) Ethanol extract of DSS decreased the production of superoxide and peroxynitrite; 4) Ethanol extract of DSS significantly down-regulated the expression of p67^phox but has no effect on p47^phox and iNOS statistically. 5) Ethanol extract of DSS significantly up-regulated the expression of SIRT1 in the cortex and striatum of the post-ischemic brains; 6) Co-treatment of EX527, a SIRT1 inhibitor, abolished the DSS’s neuroprotective effects. Taken together, DSS could attenuate oxidative/nitrosative stress and inhibit neuronal apoptosis against cerebral ischemic-reperfusion injury via SIRT1-dependent manner.

Promotion of Momordica Charantia polysaccharides on neural stem cell proliferation by increasing SIRT1 activity after cerebral ischemia/reperfusion in rats

The deacetylase SIRT1 has been reported to play a critical role in regulating neurogenesis, which may be an adaptive processes contributing to recovery after stroke. Our previous work showed that the antioxidant capacity of Momordica charantia polysaccharides (MCPs) could protect against cerebral ischemia/reperfusion (I/R) after stroke. However, whether the protective effect of MCPs on I/R injury is related to neural stem cell (NSC) proliferation remains unclear. In the present study, we designed invivo and invitro experiments to elucidate the underlying mechanisms by which MCPs promote endogenous NSC proliferation during cerebral I/R. Invivo results showed that MCPs rescued the memory and learning abilities of rats after I/R damage and enhanced NSC proliferation in the rat subventricular zone (SVZ) and subgrannular zone (SGZ) during I/R. Invitro experiments demonstrated that MCPs could stimulate the proliferation of C17.2 cells under oxygen-glucose deprivation (OGD) conditions. Further studies revealed that the proliferation-promoting mechanism of MCPs relied on increasing the activity of SIRT1, decreasing the level of acetylation of β-catenin in the cytoplasm, and then triggering the translocation of β-catenin into the nucleus. These data provide experimental evidence that the up-regulation of SIRT1 activity by MCPs led to an increased cytoplasmic deacetylation of β-catenin, which promoted translocation of β-catenin to the nucleus to participate in the signaling pathway involved in NSC proliferation. The present study reveals that MCPs function as a therapeutic drug to promote stroke recovery by increasing the activity of SIRT1, decreasing the level of acetylated β-catenin, promoting the nuclear translocation of β-catenin and thereby increasing endogenous NSC proliferation.

Anti-cerebral ischemia reperfusion injury of polysaccharides: A review of the mechanisms

Cerebral ischemia-reperfusion injury can lead to a series of serious brain diseases and cause death or different degrees of disability. Polysaccharide is a kind of biological macromolecule with multiple pharmacological activities and has been proven that it may be used for the treatment of cerebral I/R injury in the future. By sorting out all relevant research from 2000 to 2020, we selected 74 references and identified 22 kinds of polysaccharides. Almost all of these polysaccharides are extracted from traditional Chinese medicine. Research shows that these polysaccharides can improve cerebral ischemia-reperfusion injury through anti-oxidative stress, inhibiting the neuroinflammation, glutamate neurotoxicity and neuronal apoptosis, and exerting neurotrophic effect. The specific mechanisms include clearing ROS and RNS, inhibiting the expression of inflammatory factors, maintaining mitochondrial homeostasis and blocking caspase cascade, regulating NMDA receptor and promoting angiogenesis. We hoped this review is instructive for researchers to design, research and develop polysaccharides.

Protective effects of polysaccharides on cerebral ischemia: A mini-review of the mechanisms

Cerebral ischemia, a common cerebrovascular disease, is one of the great threats to human health. Nowadays, many drugs used in the treatment of cerebral ischemia such as clot busting drugs, antiplatelet drugs, and neuroprotective drugs have limits. It is urgent finding new effective treatments for the patients. Researches have confirmed that many kinds of polysaccharides from natural resources possess therapeutic effects on cerebral ischemia, but are still lack of a comprehensively understanding. In this paper, based on the pathophysiology of cerebral ischemic injury, we summarize the latest discoveries and advancements of 29 kinds of polysaccharides, focusing on their ameliorating effects on cerebral ischemia and the underlying mechanisms. Several mechanisms are involved, mainly including antioxidant activities, anti-inflammatory activities, regulating neuron apoptosis, as well as resisting nitrosative stress injury. Besides, polysaccharides show protective effects through certain signaling pathways including PI3K/Akt, MAPK, and NF-κB, PARP-1/AIF, JNK3/c-Jun/Fas-L, and Nrf2/HO-1 signaling pathways. The main goal of this mini-review is to emphasize the important roles of polysaccharides in attenuating cerebral ischemic injury through the elucidation of mechanisms.

Neuroinflammation in hemorrhagic transformation after tissue plasminogen activator thrombolysis: Potential mechanisms, targets, therapeutic drugs and biomarkers

Hemorrhagic transformation (HT) is a common and serious complication following ischemic stroke, especially after tissue plasminogen activator (t-PA) thrombolysis, which is associated with increased mortality and disability. Due to the unknown mechanisms and targets of HT, there are no effective therapeutic drugs to decrease the incidence of HT. In recent years, many studies have found that neuroinflammation is closely related to the occurrence and development of HT after t-PA thrombolysis, including glial cell activation in the brain, peripheral inflammatory cell infiltration and the release of inflammatory factors, involving inflammation-related targets such as NF-κB, MAPK, HMGB1, TLR4 and NLRP3. Some drugs with anti-inflammatory activity have been shown to protect the BBB and reduce the risk of HT in preclinical experiments and clinical trials, including minocycline, fingolimod, tacrolimus, statins and some natural products. In addition, the changes in MMP-9, VAP-1, NLR, sICAM-1 and other inflammatory factors are closely related to the occurrence of HT, which may be potential biomarkers for the diagnosis and prognosis of HT. In this review, we summarize the potential inflammation-related mechanisms, targets, therapeutic drugs, and biomarkers associated with HT after t-PA thrombolysis and discuss the relationship between neuroinflammation and HT, which provides a reference for research on the mechanisms, prevention and treatment drugs, diagnosis and prognosis of HT.

Momordica charantia polysaccharides modulate the differentiation of neural stem cells via SIRT1/Β-catenin axis in cerebral ischemia/reperfusion

BACKGROUND

Stroke is the leading cause of long-term motor disability and cognitive impairment. Recently, neurogenesis has become an attractive strategy for the chronic recovery of stroke. It is important to understand the molecular mechanism that promotes neural stem cell (NSC) neurogenesis for future NSC-based therapies. Our previous study showed that Momordica charantia polysaccharides (MCPs) exerted neuroprotective effects on stroke via their anti-oxidant and anti-inflammation activities. However, it remains unknown whether MCPs promote NSC neurogenesis after cerebral ischemic/reperfusion injury (IRI).

METHODS

We investigated MCPs' function in differentiation of neural stem cells (NSCs) in vivo and in vitro experiments. Based on a middle cerebral artery occlusion (MCAO) rat model, the effect of MCPs on neuronal differentiation after MCAO was analyzed. Primary NSCs and neural stem cell line C17.2 were cultured and subjected to glutamate stimulation to establish the cell model of IRI. We evaluated the effect of MCPs on NSC differentiation in IRI cell model by Western blot and immunofluorescence staining. The SIRT1 activity of NSCs post glutamate stimulation was also evaluated by CELL SIRT1 COLORIMETRY ASSAY KIT. In addition, molecular mechanism was clarified by employing the activator and inhibitor of SIRT1.

RESULTS

MCPs had no effects on the differentiation of neural stem cells under physiological conditions while shifted NSC differentiation potential from the gliogenic to neurogenic lineage under pathological conditions. Activation of SIRT1 with MCPs was responsible for the neuronal differentiation of C17.2-NSCs. The neuronal differentiation effect of MCPs was attributed to upregulation SIRT1-mediated deacetylation of β-catenin. MCP-induced deacetylation via SIRT1 promoted nuclear accumulation of β-catenin in NSCs.

CONCLUSION

Our findings indicate that the deacetylation of β-catenin by SIRT1 represents a critical mechanism of action of MCPs in promoting NSC neuronal differentiation. It provides an improved understanding of molecular mechanism underlying neuroprotective effects of MCPs in IRI, indicating its potential role on treating ischemic stroke especially chronic recovery.

Production, physicochemical characteristics, and in vitro biological activities of polysaccharides obtained from fresh bitter gourd (Momordica charantia L.) via room temperature extraction techniques

In this study, polysaccharides (BPSs) were obtained from fresh bitter gourd (Momordica charantia L.) by room temperature extraction techniques, including three-phase partitioning (TPP) and ultrasonic-assisted extraction (UAE) performed in different solvents. The results showed that the extraction methods had significant influence on the extraction yield, chemical composition, weight-average molecular weight (M_w), monosaccharide composition, preliminary structural characterization and microstructure of the BPSs. The BPS-W sample obtained from the bitter gourd residue via UAE in distilled water had a higher uronic acid content (24.22%) and possessed stronger antioxidant capacities and α-amylase and α-glycosidase inhibitory activities than BPS-C extracted with UAE in citric acid, BPS-A extracted with UAE in 1.25 mol/L NaOH/0.05% NaBH₄, and BPS-J extracted from bitter gourd juice by TPP. Moreover, BPS-A, which had the lowest M_ws, showed the best bile acid-binding capacity among the four BPSs. This study had great potentials for the preparation of bioactive polysaccharides from fresh vegetables.

Protein extracts from Momordica charantia var. charantia and M. charantia var. muricata show anti-lipidemic and antioxidant properties in experimental type 2 diabetic rats

Plant-derived compounds are used to manage dyslipidemia and oxidative stress in type 2 diabetic condition. In this study, anti-lipidemic and antioxidant properties of the protein extracts from "Charantia" (PEC) and "Muricata" (PEM) varieties of Momordica charantia were analyzed by quantifying lipids, hepatic, renal, and oxidative stress markers, and histopathological examination of liver and kidney tissues. Protein extracts were orally administered at 10 (PEC10, PEM10) or 20 mg/kg body weight (PEC20, PEM20). Levels of cholesterol, low-density lipoprotein, and triglycerides decreased but high-density lipoprotein increased significantly in treated rats as compared to untreated diabetic rats (p < .01), and attained normal physiological range in both doses. Levels of superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione increased but thiobarbituric acid reactive substances decreased significantly in treated rats as compared to untreated diabetic rats (p < .01), and attained normal physiological range in PEM20 only. Histopathological examinations supported a protective role for the protein extracts against oxidative stress. PRACTICAL APPLICATIONS: Momordica charantia, a well-known medicinal plant is traditionally used for treating diabetes in India as well as other countries. The whole plant was shown to have medicinal importance. Anti-diabetic potential of this plant was scientifically established largely using organic extracts and water extract mainly from the fruits of this plant. However, protein extracts from the seeds and fruit pulp of this plant were also proven to have anti-diabetic activity. The present study illustrates the anti-lipidemic and antioxidant effect of protein extracts from the fruit pulp of two varieties of M. charantia (Charantia and Muricata) in Streptozotocin-induced type 2 diabetic rats. This study provides experimental evidence in support of its use in the management of type 2 diabetes-related complications.

Targeting Myeloperoxidase (MPO) Mediated Oxidative Stress and Inflammation for Reducing Brain Ischemia Injury: Potential Application of Natural Compounds

Oxidative stress and inflammation are two critical pathological processes of cerebral ischemia-reperfusion injury. Myeloperoxidase (MPO) is a critical inflammatory enzyme and therapeutic target triggering both oxidative stress and neuroinflammation in the pathological process of cerebral ischemia-reperfusion injury. MPO is presented in infiltrated neutrophils, activated microglial cells, neurons, and astrocytes in the ischemic brain. Activation of MPO can catalyze the reaction of chloride and H2O2 to produce HOCl. MPO also mediates oxidative stress by promoting the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), modulating the polarization and inflammation-related signaling pathways in microglia and neutrophils. MPO can be a therapeutic target for attenuating oxidative damage and neuroinflammation in ischemic stroke. Targeting MPO with inhibitors or gene deficiency significantly reduced brain infarction and improved neurological outcomes. This article discusses the important roles of MPO in mediating oxidative stress and neuroinflammation during cerebral ischemia-reperfusion injury and reviews the current understanding of the underlying mechanisms. Furthermore, we summarize the active compounds from medicinal herbs with potential as MPO inhibitors for anti-oxidative stress and anti-inflammation to attenuate cerebral ischemia-reperfusion injury, and as adjunct therapeutic agents for extending the window of thrombolytic treatment. We highlight that targeting MPO could be a promising strategy for alleviating ischemic brain injury, which merits further translational study.

Therapeutic targets of oxidative/nitrosative stress and neuroinflammation in ischemic stroke: Applications for natural product efficacy with omics and systemic biology

Oxidative/nitrosative stress and neuroinflammation are critical pathological processes in cerebral ischemia-reperfusion injury, and their intimate interactions mediate neuronal damage, blood-brain barrier (BBB) damage and hemorrhagic transformation (HT) during ischemic stroke. We review current progress towards understanding the interactions of oxidative/nitrosative stress and inflammatory responses in ischemic brain injury. The interactions between reactive oxygen species (ROS)/reactive nitrogen species (RNS) and innate immune receptors such as TLR2/4, NOD-like receptor, RAGE, and scavenger receptors are crucial pathological mechanisms that amplify brain damage during cerebral ischemic injury. Furthermore, we review the current progress of omics and systematic biology approaches for studying complex network regulations related to oxidative/nitrosative stress and inflammation in the pathology of ischemic stroke. Targeting oxidative/nitrosative stress and neuroinflammation could be a promising therapeutic strategy for ischemic stroke treatment. We then review recent advances in discovering compounds from medicinal herbs with the bioactivities of simultaneously regulating oxidative/nitrosative stress and pro-inflammatory molecules for minimizing ischemic brain injury. These compounds include sesamin, baicalin, salvianolic acid A, 6-paradol, silymarin, apocynin, 3H-1,2-Dithiole-3-thione, (-)-epicatechin, rutin, Dl-3-N-butylphthalide, and naringin. We finally summarize recent developments of the omics and systematic biology approaches for exploring the molecular mechanisms and active compounds of Traditional Chinese Medicine (TCM) formulae with the properties of antioxidant and anti-inflammation for neuroprotection. The comprehensive omics and systematic biology approaches provide powerful tools for exploring therapeutic principles of TCM formulae and developing precision medicine for stroke treatment.

Acteoside ameliorates experimental autoimmune encephalomyelitis through inhibiting peroxynitrite-mediated mitophagy activation

Multiple sclerosis (MS) is an inflammatory disease in central nervous system (CNS) with limited therapeutic drugs. In the present study, we explored the anti-inflammatory/neuroprotective properties of Acteoside (AC), an active compound from medicinal herb Radix Rehmanniae (RR), and neuroprotective effects of AC on MS pathology by using an experimental autoimmune encephalomyelitis (EAE) model. We tested the hypothesis that AC could alleviate EAE pathogenesis through inhibiting inflammation and ONOO^--mediated mitophagy activation in vivo and in vitro. The results showed that AC treatment effectively ameliorated neurological deficit score and postponed disease onset in the EAE mice. AC treatment inhibited inflammation/demyelination, alleviated peripheral activation and CNS infiltration of encephalitogenic CD4⁺ T cells and CD11b⁺ activated microglia/macrophages in the spinal cord of EAE mice. Meanwhile, AC treatment reduced ONOO^- production, down-regulated the expression of iNOS and NADPH oxidases, and inhibited neuronal apoptotic cell death and mitochondrial damage in the spinal cords of the EAE mice. Furthermore, AC treatment decreased the ratio of LC3-II to LC3-I in mitochondrial fraction, and inhibited the translocation of Drp1 to the mitochondria. In vitro studies further proved that AC possessed strong ONOO^- scavenging capability and protected the neuronal cells from nitrative cytotoxicity via suppressing ONOO^--mediated excessive mitophagy. Taken together, Acteoside could be a potential therapeutic agent for multiple sclerosis treatment. The suppression of ONOO^--induced excessive mitophagy activation could be one of the critical mechanisms contributing to its anti-inflammatory and anti-demyelinating properties.

Nitration of Drp1 provokes mitophagy activation mediating neuronal injury in experimental autoimmune encephalomyelitis

Active autophagy/mitophagy could mediate neurodegeneration and motor disabilities in multiple sclerosis (MS). Mitochondrial recruitment of dynamin-related protein 1 (Drp1) is a crucial step to initiate mitophagy. Peroxynitrite (ONOO^-) could be a player in MS pathology but the mechanisms remain unknown. We used animal model of experimental autoimmune encephalomyelitis (EAE) and tested whether ONOO^- mediates Drp1 assembly in mitochondria for mitophagy and aggravates MS pathology. We found that autophagy/mitophagy activation was coincidently increased with axonal damage, apoptosis and disease progression in active EAE mice, which were remarkably attenuated by mitochondrial division/mitophagy inhibitor Mdivi-1. Importantly, increased ONOO^- production was companied with Drp1 mitochondrial recruitment, PINK1/Parkin-mediated mitophagy, axonal degeneration and neuronal cell death, which were reversed by peroxynitrite decomposition catalyst (PDC). Furthermore, ONOO^- production induced Drp1 nitration, promoted Drp1 assembly and mitochondrial recruitment for mitophagy activation, contributing to the EAE pathology. Together, we conclude that ONOO^- serves as a key mediator in Drp1 nitration modification and assembly for facilitating mitophagy activation. Targeting ONOO^--mediated Drp1 assembly and mitochondrial recruitment could be an important therapeutic strategy for multiple sclerosis treatment.

Galuteolin attenuates cerebral ischemia/reperfusion injury in rats via anti-apoptotic, anti-oxidant, and anti-inflammatory mechanisms

PURPOSE

Galuteolin is a substance extracted and purified from honeysuckle. The purpose of this study was to explore the protective effect of galuteolin on cerebral ischemia-reperfusion injury (CIRI) and reveal its potential molecular mechanism from the perspectives of anti-apoptosis, anti-oxidation, and anti-inflammation.

MATERIALS AND METHODS

One hundred and fifty rats were randomly divided into five groups: sham group, ischemia-reperfusion (I/R) group, 50 mg/kg galuteolin group, 100 mg/kg galuteolin group, and 200 mg/kg galuteolin group. Middle cerebral artery occlusion (MCAO) was used to establish a rat CIRI model, different doses of galtenolin were intraperitoneal injected 2 hrs after ischemia, and then reperfusion was performed for 24 hrs. Neurological function and cerebral water content were determined, and cerebral infarct volume was evaluated by TTC staining. TUNEL staining was used to detect the apoptosis of nerve cells. Western Blot was used to detect the expressions of Akt, p-Akt, Sod1, Sod2, catalase, caspase-3, Bcl-2, and Bax. Lipid hydrogen peroxide (LPO) was determined by kit assay. The contents of vascular endothelial growth factor (VEGF) and pro-inflammatory cytokines IL-1β and TNF-α were determined by ELISA.

RESULTS

The results showed that galuteolin could significantly reduce the cerebral infarction volume, neurologic score, and cerebral water content in a dose-dependent manner. In addition, galuteolin obviously reduced the apoptosis rate of nerve cells and the expression levels of caspase-3 and Bax, meanwhile up-regulated the expression levels of p-Akt and Bcl-2. Furthermore, galuteolin apparently inhibited the levels of LPO, Sod1, Sod2, and catalase in the cerebral infarction tissues. Moreover, galuteolin also significantly reduced the levels of pro-inflammatory factors IL-1β and TNF-α in the cerebral infarction tissues. Finally, Galuteolin markedly inhibited the expression of VEGF in cerebral infarction tissues.

CONCLUSION

Galuteolin exerts neuroprotective effects against CIRI by inhibiting apoptosis, oxidation, and inflammation.

Momordica charantia, a Nutraceutical Approach for Inflammatory Related Diseases

Momordica charantia, commonly called bitter melon, is a plant belonging to Cucurbitaceae family known for centuries for its pharmacological activities, and nutritional properties. Due to the presence of many bioactive compounds, some of which possess potent biological actions, this plant is used in folk medicine all over the world for the treatment of different pathologies, mainly diabetes, but also cancer, and other inflammation-associated diseases. It is widely demonstrated that M. charantia extracts contribute in lowering glycaemia in patients affected by type 2 diabetes. However, the majority of existing studies on M. charantia bioactive compounds were performed only on cell lines and in animal models. Therefore, because the real impact of bitter melon on human health has not been thoroughly demonstrated, systematic clinical studies are needed to establish its efficacy and safety in patients. Besides, both in vitro and in vivo studies have demonstrated that bitter melon may also elicit toxic or adverse effects under different conditions. The aim of this review is to provide an overview of anti-inflammatory and anti-neoplastic properties of bitter melon, discussing its pharmacological activity as well as the potential adverse effects. Even if a lot of literature is available about bitter melon as antidiabetic drug, few papers discuss the anti-inflammatory and anti-cancer properties of this plant.

Behavioral defects induced by chronic social defeat stress are protected by Momordica charantia polysaccharides via attenuation of JNK3/PI3K/AKT neuroinflammatory pathway

Background

The aim of this study was to evaluate the protective effects of Momordica charantia polysaccharides (MCP) on depressive-like behaviors.

Methods

The chronic social defeat stress (CSDS) mice model was used to evaluate the effects of MCP and their underlying mechanisms. Social interaction test (SIT), sucrose preference test (SPT), and tail suspension test (TST) were performed for behavioral assessments. Expression levels of inflammation mediators and phosphatidylinositol 3-kinase (PI3K) activity were determined using commercial ELISA kits. The expression of key proteins in the c-Jun N-terminal protein kinase (JNK3)/PI3K/protein kinase B (AKT) pathway were measured using western blot and RT-PCR.

Results

The results showed that chronic administration of MCP (100, 200, 400 mg/kg/day) significantly prevented depressive-like behaviors in CSDS mice as assessed by SIT, TST and SPT. Elevated levels of proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β)], and expression of JNK3, c-Jun, P-110β proteins were observed in the hippocampus of CSDS mice. Moreover, the activity of PI3K and phosphorylation level of AKT were reduced in the hippocampus of CSDS mice. Interestingly, the administration of MCP reversed these changes. Furthermore, the protective effects of MCP on CSDS mice were partly inhibited by the PI3K inhibitor, LY294002.

Conclusions

In conclusion, the protective effects of MCP against depressive-like behaviors in CSDS mice might be due to a reduction in neuroinflammation and the down-regulation of the JNK3/PI3K/AKT pathway in the hippocampus.

Protective effect of polysaccharide peptide on cerebral ischemia‑reperfusion injury in rats

In the present study, the protective effects and regulatory mechanism of polysaccharide peptide (PSP) were investigated in rats with cerebral ischemia-reperfusion (IR) injury. Neuroblastoma N2a cells were divided into five groups: Negative control; IR injury; PSP low dose treatment; PSP middle dose treatment; and PSP high dose treatment. In vitro, the cell viability was detected by an MTT assay. ELISA was performed to determine the activity of lactate dehydrogenase (LDH) and caspase-3. A cerebral IR injury model in vivo was established, and hematoxylin and eosin (H&E) staining, western blotting, neurological deficit score and cerebral infarction were assessed. The cell viability was markedly improved following treatment with PSP and the activity of LDH and caspase-3 was decreased following PSP administration (P<0.05). The in vivo studies determined that the neurological deficit score and cerebral infarction volume were reduced with the concentration of PSP increasing between 150 and 250 mg/kg. The H&E staining indicated that PSP was able to protect the nerve cells against the cerebral IR injury. In addition, PSP upregulated the decreased silent information regulator protein 1, peroxisome proliferator-activated receptor γ coactivator-1α and apoptosis regulator B-cell lymphoma 2 expression induced by cerebral IR injury. The protein expression level of caspase-3 and apoptosis regulator apoptosis regulator Bcl-2-like protein 4 was downregulated following PSP administration. These results suggested that PSP may improve nerve cell viability, enhance the neuroprotective role in cerebral IR injury and provide a novel approach for the treatment of cerebral IR injury.

Isolation, Structures, and Bioactivities of the Polysaccharides from Gynostemma pentaphyllum (Thunb.) Makino: A Review

Polysaccharides obtained from Gynostemma pentaphyllum (Thunb.) Makino have promising prospects in functional food and nutraceuticals due to its broad range of biological activities including antioxidant, immunomodulatory, antitumor, hepatoprotective, neuroprotective, and antifatigue activities. These beneficial biological activities are related to chemical composition and structure of the G. pentaphyllum polysaccharides. The molecular weight, monosaccharide composition, and chemical structures could be influenced by both different extraction/purification techniques employed to obtain polysaccharide enriched products. The purpose of this article is to review previous and current literature regarding the extraction, purification, structural characterization, and biological activity of G. pentaphyllum polysaccharides. This review provides a useful bibliography for the further investigation, production, and application of G. pentaphyllum polysaccharides as functional foods and nutraceuticals.

Molecular docking analysis of phytoconstituent from Momordica charantia with Guanylate Cyclase catalytic domain

Soluble guanylate cyclase (sGC) is a type of lyase enzyme with profoundly increasing importance in treatments of cardiovascular and neurodegenerative disorders. Modulation of sGC activity demonstrated beneficial effects against Parkinson's disease by reducing glutamate excitotoxicity. It is of interest to evaluate the pharmacological activity of Momordica charantia phytoconstituent (DGalacturonic acid) and ODQ with catalytic domain of sGC enzyme, using Autodock version 4.2 programs. Docking results revealed the binding ability of ODQ at the allosteric sites of sGC. D-galacturonic acid also shows binding interaction at the same allosteric sites in the catalytic domain of sGC like ODQ. Results show that both the ligands have efficient binding to THR 474 amino acid residue of beta 1 subunit of the enzyme. The drug likeliness score further implies the suitability of D-Galacturonic acid as a drug-like molecule. The binding property of ODQ and D-Galacturonic acid with the catalytic domain help to inhibit sGC activity having pharmacological effects. Moreover, ODQ interaction with heme site of sGC is already known while its interaction with the catalytic domain is shown in this report.

Momordica charantia Ethanol Extract Attenuates H₂O₂-Induced Cell Death by Its Antioxidant and Anti-Apoptotic Properties in Human Neuroblastoma SK-N-MC Cells

Oxidative stress, which is induced by reactive oxygen species (ROS), causes cellular damage which contributes to the pathogenesis of neurodegenerative diseases. Momordica charantia (MC), a traditional medicinal plant, is known to have a variety of health benefits, such as antidiabetic, anti-inflammatory, and antioxidant effects. However, it is unknown whether MC has protective effects against oxidative stress-induced neuronal cell death. The aim of this study was to investigate the potential action of MC on oxidative stress induced by H₂O₂. First, we tested whether the pretreatment of Momordica charantia ethanol extract (MCEE) attenuates H₂O₂-induced cell death in human neuroblastoma SK-N-MC cells. MCEE pretreatment significantly improved cell viability and apoptosis that deteriorated by H₂O₂. Further, MCEE ameliorated the imbalance between intracellular ROS production and removal through the enhancement of the intracellular antioxidant system. Intriguingly, the inhibition of apoptosis was followed by the blockage of mitochondria-dependent cell death cascades and suppression of the phosphorylation of the mitogen-activated protein kinase signaling (MAPKs) pathway by MCEE. Taken together, MCEE was shown to be effective in protecting against H₂O₂-induced cell death through its antioxidant and anti-apoptotic properties.

Radix Rehmanniae Extract Ameliorates Experimental Autoimmune Encephalomyelitis by Suppressing Macrophage-Derived Nitrative Damage

Multiple sclerosis (MS) is a neuroinflammatory disease in central nervous system (CNS) without effective treatment or medication yet. With high prevalence of MS patients worldwide and poor therapeutic outcome, seeking novel therapeutic strategy for MS is timely important. Radix Rehmanniae (RR), a typical Chinese Medicinal herb, has been used for neuroinflammatory diseases in Traditional Chinese Medicine for centuries. However, scientific evidence and underlying mechanisms of RR for MS are unclear. In this study, we tested the hypothesis that RR could attenuate the progress and severity of MS via suppressing macrophage-derived nitrative damage and inflammation by using experimental autoimmune encephalomyelitis (EAE) model for mimicking MS pathology. The results showed the RR treatment effectively ameliorated clinical disease severity, inhibited inflammation/demyelination in spinal cord, and alleviated CNS infiltration of encephalitogenic T cells and activated macrophages. Meanwhile, RR possessed bioactivities of scavenging ONOO- and reducing the expression of iNOS and NADPH oxidases in the spinal cords of the EAE mice. Furthermore, RR treatment suppressed nuclear factor-κB (NF-κB) signaling pathway in the splenocytes of EAE mice. The in vitro experiments on macrophages and neuronal cells exerted consistent results with the in vivo animal experiments. Taken together, we conclude that Radix Rehmanniae extract has therapeutic values for ameliorating EAE/MS pathological process and disease severity and its underlying mechanisms are associated with anti-inflammation and inhibiting macrophage-derived nitrative damages. Further study could yield novel promising therapeutic agent for multiple sclerosis.