Protopanaxadiol ginsenoside Rd protects against NMDA receptor-mediated excitotoxicity by attenuating calcineurin-regulated DAPK1 activity

Neuroprotection and mechanisms of ginsenosides in nervous system diseases: Progress and perspectives

Ginsenosides are the primary component discernible from ginseng, including Rb1, Rb2, Rd, Rg1, Rg2, and compound K, and so forth. They have been shown to have multiple pharmacological activities. In recent years, more and more studies have been devoted to the neuroprotection of various ginsenosides against neurological diseases and their potential mechanisms. This paper comprehensively summarizes and reviews the neuroprotective effects of various ginsenosides on neurological diseases, especially acute and chronic neurodegenerative diseases, and their mechanisms, as well as their potential therapeutic applications to promote neuroprotection in disease prevention, treatment, and prognosis. Briefly, ginsenosides exert effective neuroprotective effects on neurological conditions, including stroke, Alzheimer's disease, Parkinson's disease, and brain/spinal cord injuries through a variety of molecular mechanisms, including anti-inflammatory, antioxidant, and anti-apoptotic. Among them, some signaling pathways play important roles in related processes, such as PI3K/Akt, TLR4/NF-κB, ROS/TXNIP/NLRP3, HO-1/Nrf2, Wnt/β-catenin, and Ca2+ pathway. In conclusion, the present study reviews the research progress on the neuroprotective effects of ginsenosides in the last decade, with the aim of furnishing essential theoretical underpinning and effective references for further research and exploration of the multiple medicinal values of Chinese herbal medicines and their small molecule compounds, including ginseng and panax ginseng. Because there is less evidence in the existing clinical studies, future research should be focused on clinical trials in order to truly reflect the clinical value of various ginsenosides for the benefit of patients.

Natural herbal extract roles and mechanisms in treating cerebral ischemia: A systematic review

Background

Stroke has been the focus of medical research due to its serious consequences and sequelae. Among the tens of millions of new stroke patients every year, cerebral ischemia patients account for the vast majority. While cerebral ischemia drug research and development is still ongoing, most drugs are terminated at preclinical stages due to their unacceptable toxic side effects. In recent years, natural herbs have received considerable attention in the pharmaceutical research and development field due to their low toxicity levels. Numerous studies have shown that natural herbs exert actions that cannot be ignored when treating cerebral ischemia.

Methods

We reviewed and summarized the therapeutic effects and mechanisms of different natural herbal extracts on cerebral ischemia to promote their application in this field. We used keywords such as "natural herbal extract," "herbal medicine," "Chinese herbal medicine" and "cerebral ischemia" to comprehensively search PubMed, ScienceDirect, ScienceNet, CNKI, and Wanfang databases, after which we conducted a detailed screening and review strategy.

Results

We included 120 high-quality studies up to 10 January 2024. Natural herbal extracts had significant roles in cerebral ischemia treatments via several molecular mechanisms, such as improving regional blood flow disorders, protecting the blood-brain barrier, and inhibiting neuronal apoptosis, oxidative stress and inflammatory responses.

Conclusion

Natural herbal extracts are represented by low toxicity and high curative effects, and will become indispensable therapeutic options in the cerebral ischemia treatment field.

Ginsenoside Rd attenuates myocardial ischemia injury through improving mitochondrial biogenesis via WNT5A/Ca2+ pathways

Ginsenoside Rd, one of the main active components in ginseng, exerts various biological activities. However, its effectiveness on myocardial ischemia injury and its potential mechanism need further clarification. The model of isoproterenol (ISO)-induced myocardial ischemia injury (MI) mice and cobalt chloride (CoCl2)-induced cardiomyocytes injury were performed. Ginsenoside Rd significantly alleviated MI injury, as evidenced by ameliorated cardiac pathological features and improved cardiac function. Simultaneously, ginsenoside Rd notably mitigated CoCl2-induced cell injury, decreased the lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) generation in vitro. Additionally, ginsenoside Rd increased nicotinamide adenine dinucleotide (NADH) and mitochondrial membrane potential (MMP). Moreover, we found that ginsenoside Rd could increase the mitochondrial DNA (mtDNA) and promote the expression of Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1α), nuclear factor erythroid 2 related factor-1 (NRF1), nuclear factor erythroid 2 related factor-2 (NRF2) and activating mitochondrial transcription factor A (TFAM), which suggested that ginsenoside Rd might accelerate mitochondrial biogenesis function to ameliorate MI injury. Importantly, ginsenoside Rd treatment significantly inhibited the WNT5A/calcium (Ca2+) signaling pathway, decreased the expression of WNT5A, Frizzled2, phosphorylated calmodulin kinase II/calmodulin kinase II (p-CaMKII/CaMKII) and the calcium overload. Meanwhile, WNT5A siRNA was further conducted to elucidate the effect of ginsenoside Rd on CoCl2-induced cardiomyocyte injury. And we found that WNT5A siRNA partially weakened the protective effects of ginsenoside Rd on mitochondrial function and mitochondrial biogenesis, suggesting that ginsenoside Rd might suppress myocardial ischemia injury through WNT5A. Overall, this study demonstrated that ginsenoside Rd could alleviate myocardial ischemia injury through improving mitochondrial biogenesis via WNT5A/Ca2+ pathways, which provided a rationale for future clinical applications and potential drugs for the treatment of cardiovascular diseases.

Effects of prenatal hypoxia-ischemia on male rat periaqueductal gray matter: Hyperalgesia, astrogliosis and nitrergic system impairment

Prenatal hypoxic-ischemic insult (HI) may lead to a variety of neurological consequences that may persist throughout adulthood. In the most severe cases, HI is known to increase pain sensitivity which profoundly impacts quality of life. Periaqueductal gray matter (PAG) is a relevant region of the descending pain pathway and its function may be modulated by a complex network that includes nitrergic neurons and glial response, among other factors. Astrocytes, central players in pain modulation, are known to respond to HI by inducing hyperplasia, hypertrophy and increasing the number of their processes and the staining of glial fibrillary acidic protein (GFAP). In this work we investigated the effects of prenatal HI on touch and pain sensitivity, besides the distribution of the neuronal isoform of Nitric Oxide Synthase (nNOS) and GFAP in the PAG of young and adult male rats. At 18 days of gestation, rats had their uterine arteries clamped for 45 min (HI group). SHAM-operated animals were also generated (SHAM group). At post-natal day 30 (P30) or 90 (P90), the offspring was submitted to the behavioral tests of Von Frey and formalin or histological processing to perform immunohistochemistry for nNOS and GFAP. Although there was no significant difference between the groups concerning touch sensitivity, we observed an increase in pain sensitivity in HI P30 and HI P90. The number of nNOS + cells was reduced in HI adult animals in dlPAG and vlPAG. GFAP immunostaining was increased in HI P90 in dlPAG and dmPAG. Our results demonstrated for the first time an increase in pain sensitivity as a consequence of prenatal HI in an animal model. It reinforces the relevance of this model to mimic the effects of prenatal HI, as hyperalgesia.

Ginsenoside Rd promotes omentin secretion in adipose through TBK1-AMPK to improve mitochondrial biogenesis via WNT5A/Ca2+ pathways in heart failure

Ginsenoside Rd is an active ingredient in Panax ginseng CA Mey and can be absorbed into the adipose tissue. Adipokines play an important role in the treatment of cardiovascular diseases. However, the potential benefit of Rd on heart failure (HF) and the underlying mechanism associated with the crosstalk between adipocytes and cardiomyocytes remains to be illustrated. Here, the results identified that Rd improved cardiac function and inhibited cardiac pathological changes in transverse aortic constriction (TAC), coronary ligation (CAL) and isoproterenol (ISO)-induced HF mice. And Rd promoted the release of omentin from the adipose tissue and up-regulated omentin expression in lipopolysaccharide (LPS)-induced 3T3-L1 adipocytes. Further, Rd could increase TBK1 and AMPK phosphorylation in adipocytes. And also, the TBK1-AMPK signaling pathway regulated the expression of omentin in LPS-induced adipocytes. Moreover, the omentin mRNA expression was significantly decreased by TBK1 knockdown in LPS-induced 3T3-L1 adipocytes. Additionally, molecular docking and SPR analysis confirmed that Rd had a certain binding ability with TBK1, and co-treatment with TBK1 inhibitors or TBK1 knockdown partially abolished the effect of Rd on increasing the omentin expression and the ratio of p-AMPK to AMPK in adipocytes. Moreover, we found that circulating omentin level diminished in the HF patients compared with healthy subjects. Meanwhile, the adipose tissue-specific overexpression of omentin improved cardiac function, reduced myocardial infarct size and ameliorated cardiac pathological features in CAL-induced HF mice. Consistently, exogenous omentin reduced mtROS levels and restored ΔψM to improve oxygen and glucose deprivation (OGD)-induced cardiomyocytes injury. Further, omentin inhibited the WNT5A/Ca²⁺ signaling pathway and promoted mitochondrial biogenesis function to ameliorate myocardial ischemia injury. However, WNT5A knockdown inhibited the impairment of mitochondrial biogenesis and partially counteracted the cardioprotective effect of omentin in vitro. Therefore, this study indicated that Rd promoted omentin secretion from adipocytes through the TBK1-AMPK pathway to improve mitochondrial biogenesis function via WNT5A/Ca²⁺ signaling pathway to ameliorate myocardial ischemia injury, which provided a new therapeutic mechanism and potential drugs for the treatment of HF.

Pharmacological effects of natural medicine ginsenosides against Alzheimer's disease

Ginsenosides are the most important pharmacological active ingredient of ginseng, with multiple biological therapeutic targets, mild action and no side effects. It is having shown beneficial effects in vitro and in vivo models of AD. In this review, we analyze large literature, summarize the inhibition of ginsenosides fibrous extracellular deposition of β-amyloid (Aβ) and neurofibrillary tangles (NFTs) of possible mechanisms, and explain the effects of ginsenosides on AD neuroprotection from the aspects of antioxidant, anti-inflammatory, and anti-apoptosis, prove the potential of ginsenosides as a new class of drugs for the treatment of AD. In addition, according to the current clinical application status of natural drugs, this paper analysis the delivery route and delivery mode of ginsenosides from the perspective of pharmacokinetics, providing a deeper insight into the clinical application of ginsenosides in the treatment of AD.

Neuroprotective Effect and Possible Mechanisms of Ginsenoside-Rd for Cerebral Ischemia/Reperfusion Damage in Experimental Animal: A Meta-Analysis and Systematic Review

Ischemic stroke, the most common type of stroke, can lead to a long-term disability with the limitation of effective therapeutic approaches. Ginsenoside-Rd (G-Rd) has been found as a neuroprotective agent. In order to investigate and discuss the neuroprotective function and underlying mechanism of G-Rd in experimental animal models following cerebral ischemic/reperfusion (I/R) injury, PubMed, Embase, SinoMed, and China National Knowledge Infrastructure were searched from their inception dates to May 2022, with no language restriction. Studies that G-Rd was used to treat cerebral I/R damage in vivo were selected. A total of 18 articles were included in this paper, and it was showed that after cerebral I/R damage, G-Rd administration could significantly attenuate infarct volume (19 studies, SMD = −1.75 [−2.21 to − 1.30], P < 0.00001). Subgroup analysis concluded that G-Rd at the moderate doses of >10- <50 mg/kg reduced the infarct volume to the greatest extent, and increasing the dose beyond 50 mg/kg did not produce better results. The neuroprotective effect of G-Rd was not affected by other factors, such as the animal species, the order of administration, and the ischemia time. In comparison with the control group, G-Rd administration could improve neurological recovery (lower score means better recovery: 14 studies, SMD = −1.50 [−2.00 to − 1.00], P < 0.00001; higher score means better recovery: 8 studies, SMD = 1.57 [0.93 to 2.21], P < 0.00001). In addition, this review suggested that G-Rd in vivo can antagonize the reduced oxidative stress, regulate Ca²⁺, and inhibit inflammatory, resistance to apoptosis, and antipyroptosis on cerebral I/R damage. Collectively, G-Rd is a promising natural neuroprotective agent on cerebral I/R injury with unique advantages and a clear mechanism of action. More clinical randomized, blind-controlled trials are also needed to confirm the neuroprotective effect of G-Rd on cerebral I/R injury.

Alteration of brain functional networks induced by electroacupuncture stimulation in rats with ischemia–reperfusion: An independent component analysis

Motor dysfunction is the major sequela of ischemic stroke. Motor recovery after stroke has been shown to be associated with remodeling of large-scale brain networks, both functionally and structurally. Electroacupuncture (EA) is a traditional Chinese medicine application that has frequently been recommended as an alternative therapy for ischemic stroke and is reportedly effective for alleviating motor symptoms in patients. In the present study, the effect of EA on the alterations of functional resting state networks (RSNs) was explored after middle cerebral artery occlusion/reperfusion (MCAO/R) injury using resting-state functional MRI. Rats were randomly assigned to three groups, including the sham group, MCAO/R group and MCAO/R+EA group. The ladder rung walking test was conducted prior to and after modeling to assess behavioral changes. RSNs were identified based on the independent component analysis (ICA) performed on the fMRI data from groups. EA treatment effectively reduced the occurrence of contralateral forelimb foot faults. Furthermore, our results suggested the disrupted function of the whole-brain network following ischemic stroke and the modulatory effect of acupuncture. The sensorimotor network (SMN), interoceptive network (IN), default mode network (DMN) and salience network (SN) were related to the therapeutic effect of EA on stroke recovery. Collectively, our findings confirmed the effect of EA on motor function recovery after cerebral ischemia reperfusion and shed light on the assessment of EA intervention-induced effects on brain networks. This study provides neuroimaging evidence to explain the therapeutic effects of EA in ischemic stroke and will lay the groundwork for further studies.

Biotransformation, Pharmacokinetics, and Pharmacological Activities of Ginsenoside Rd Against Multiple Diseases

Panax ginseng C.A. Mey. has a history of more than 4000 years and is widely used in Asian countries. Modern pharmacological studies have proved that ginsenosides and their compounds have a variety of significant biological activities on specific diseases, including neurodegenerative diseases, certain types of cancer, gastrointestinal disease, and metabolic diseases, in which most of the interest has focused on ginsenoside Rd. The evidentiary basis showed that ginsenoside Rd ameliorates ischemic stroke, nerve injury, cancer, and other diseases involved in apoptosis, inflammation, oxidative stress, mitochondrial damage, and autophagy. In this review, we summarized available reports on the molecular biological mechanisms of ginsenoside Rd in neurological diseases, cancer, metabolic diseases, and other diseases. We also discussed the main biotransformation pathways of ginsenoside Rd obtained by fermentation.

A Review of Neuroprotective Effects and Mechanisms of Ginsenosides From Panax Ginseng in Treating Ischemic Stroke

Ischemic stroke has been considered one of the leading causes of mortality and disability worldwide, associated with a series of complex pathophysiological processes. However, effective therapeutic methods for ischemic stroke are still limited. Panax ginseng, a valuable traditional Chinese medicine, has been long used in eastern countries for various diseases. Ginsenosides, the main active ingredient of Panax ginseng, has demonstrated neuroprotective effects on ischemic stroke injury during the last decade. In this article, we summarized the pathophysiology of ischemic stroke and reviewed the literature on ginsenosides studies in preclinical and clinical ischemic stroke. Available findings showed that both major ginsenosides and minor ginsenosides (such as Rg3, Rg5, and Rh2) has a potential neuroprotective effect, mainly through attenuating the excitotoxicity, Ca²⁺ overload, mitochondria dysfunction, blood-brain barrier (BBB) permeability, anti-inflammation, anti-oxidative, anti-apoptosis, anti-pyroptosis, anti-autophagy, improving angiogenesis, and neurogenesis. Therefore, this review brings a current understanding of the mechanisms of ginsenosides in the treatment of ischemic stroke. Further studies, especially in clinical trials, will be important to confirm the clinical value of ginseng and ginsenosides.

Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke

Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.

Detecting Key Functional Components Group and Speculating the Potential Mechanism of Xiao-Xu-Ming Decoction in Treating Stroke

Stroke is a cerebrovascular event with cerebral blood flow interruption which is caused by occlusion or bursting of cerebral vessels. At present, the main methods in treating stroke are surgical treatment, statins, and recombinant tissue-type plasminogen activator (rt-PA). Relatively, traditional Chinese medicine (TCM) has widely been used at clinical level in China and some countries in Asia. Xiao-Xu-Ming decoction (XXMD) is a classical and widely used prescription in treating stroke in China. However, the material basis of effect and the action principle of XXMD are still not clear. To solve this issue, we designed a new system pharmacology strategy that combined targets of XXMD and the pathogenetic genes of stroke to construct a functional response space (FRS). The effective proteins from this space were determined by using a novel node importance calculation method, and then the key functional components group (KFCG) that could mediate the effective proteins was selected based on the dynamic programming strategy. The results showed that enriched pathways of effective proteins selected from FRS could cover 99.10% of enriched pathways of reference targets, which were defined by overlapping of component targets and pathogenetic genes. Targets of optimized KFCG with 56 components can be enriched into 166 pathways that covered 80.43% of 138 pathways of 1,012 pathogenetic genes. A component potential effect score (PES) calculation model was constructed to calculate the comprehensive effective score of components in the components-targets-pathways (C-T-P) network of KFCGs, and showed that ferulic acid, zingerone, and vanillic acid had the highest PESs. Prediction and docking simulations show that these components can affect stroke synergistically through genes such as MEK, NFκB, and PI3K in PI3K-Akt, cAMP, and MAPK cascade signals. Finally, ferulic acid, zingerone, and vanillic acid were tested to be protective for PC12 cells and HT22 cells in increasing cell viabilities after oxygen and glucose deprivation (OGD). Our proposed strategy could improve the accuracy on decoding KFCGs of XXMD and provide a methodologic reference for the optimization, mechanism analysis, and secondary development of the formula in TCM.

Neuronal Death Mechanisms and Therapeutic Strategy in Ischemic Stroke

Ischemic stroke caused by intracranial vascular occlusion has become increasingly prevalent with considerable mortality and disability, which gravely burdens the global economy. Current relatively effective clinical treatments are limited to intravenous alteplase and thrombectomy. Even so, patients still benefit little due to the short therapeutic window and the risk of ischemia/reperfusion injury. It is therefore urgent to figure out the neuronal death mechanisms following ischemic stroke in order to develop new neuroprotective strategies. Regarding the pathogenesis, multiple pathological events trigger the activation of cell death pathways. Particular attention should be devoted to excitotoxicity, oxidative stress, and inflammatory responses. Thus, in this article, we first review the principal mechanisms underlying neuronal death mediated by these significant events, such as intrinsic and extrinsic apoptosis, ferroptosis, parthanatos, pyroptosis, necroptosis, and autophagic cell death. Then, we further discuss the possibility of interventions targeting these pathological events and summarize the present pharmacological achievements.

Ginsenoside Rd protects cerebral endothelial cells from oxygen-glucose deprivation/reoxygenation induced pyroptosis via inhibiting SLC5A1 mediated sodium influx

Background

Ginsenoside Rd is a natural compound with promising neuroprotective effects. However, the underlying mechanisms are still not well-understood. In this study, we explored whether ginsenoside Rd exerts protective effects on cerebral endothelial cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment and its potential docking proteins related to the underlying regulations.

Method

Commercially available primary human brain microvessel endothelial cells (HBMECs) were used for in vitro OGD/R studies. Cell viability, pyroptosis-associated protein expression and tight junction protein degradation were evaluated. Molecular docking proteins were predicted. Subsequent surface plasmon resonance (SPR) technology was utilized for validation. Flow cytometry was performed to quantify caspase-1 positive and PI positive (caspase-1+/PI+) pyroptotic cells.

Results

Ginsenoside Rd treatment attenuated OGD/R-induced damage of blood-brain barrier (BBB) integrity in vitro. It suppressed NLRP3 inflammasome activation (increased expression of NLRP3, cleaved caspase-1, IL-1β and GSDMD-N terminal (NT)) and subsequent cellular pyroptosis (caspase-1+/PI + cells). Ginsenoside Rd interacted with SLC5A1 with a high affinity and reduced OGD/R-induced sodium influx and potassium efflux in HBMECs. Inhibiting SLC5A1 using phlorizin suppressed OGD/R-activated NLRP3 inflammasome and pyroptosis in HBMECs.

Conclusion

Ginsenoside Rd protects HBMECs from OGD/R-induced injury partially via binding to SLC5A1, reducing OGD/R-induced sodium influx and potassium efflux, thereby alleviating NLRP3 inflammasome activation and pyroptosis.

Insights into Recent Studies on Biotransformation and Pharmacological Activities of Ginsenoside Rd

It is well known that ginsenosides—major bioactive constituents of Panax ginseng—are attracting more attention due to their beneficial pharmacological activities. Ginsenoside Rd, belonging to protopanaxadiol (PPD)-type ginsenosides, exhibits diverse and powerful pharmacological activities. In recent decades, nearly 300 studies on the pharmacological activities of Rd—as a potential treatment for a variety of diseases—have been published. However, no specific, comprehensive reviews have been documented to date. The present review not only summarizes the in vitro and in vivo studies on the health benefits of Rd, including anti-cancer, anti-diabetic, anti-inflammatory, neuroprotective, cardioprotective, ischemic stroke, immunoregulation, and other pharmacological effects, it also delves into the inclusion of potential molecular mechanisms, providing an overview of future prospects for the use of Rd in the treatment of chronic metabolic diseases and neurodegenerative disorders. Although biotransformation, pharmacokinetics, and clinical studies of Rd have also been reviewed, clinical trial data of Rd are limited; the only data available are for its treatment of acute ischemic stroke. Therefore, clinical evidence of Rd should be considered in future studies.

Exploration of the Function of Ginsenoside RD Attenuates Lipopolysaccharide-Induced Lung Injury: A Study of Network Pharmacology and Experimental Validation

OBJECTIVE

Ginsenoside Rd (GSRd) displays a variety of pharmacological effects. However, the underlying role in acute lung injury (ALI) is not clear. In this study, the protective effect of GSRd on lipopolysaccharide (LPS)-induced ALI is investigated to explore the potential mechanisms.

METHODS

GSRd-target-ALI-related gene set was constructed. And bioinformatics tools were used to discover the potential mechanism. We observed the survival of subjects for 72 h. In addition, male BALB/c mice were intraperitoneal injected with GSRd (25 and 50 mg/kg) after received one intratracheal instillation of LPS. Inflammatory changes, oxidative stress, and phosphorylation were assessed to study the biological effects.

RESULTS

A total of 245 interaction genes were collected. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were enriched in immune-inflammatory system. Among them, PI3K-Akt signaling pathway was the highest-ranked pathway of inflammatory response. In vivo study, it was found that GSRd improved survival in endotoxemic mice and inhibited the major characteristic of ALI. And the p-PI3K and p-Akt expression was significantly decreased by GSRd treatment.

CONCLUSION

GSRd could protect mice against LPS-induced ALI effectively by inhibiting the PI3K-Akt signaling pathway.

Ginsenoside Rd: A promising natural neuroprotective agent

BACKGROUND

Neurological diseases seriously affect human health, which are arousing wider attention, and it is a great challenge to discover neuroprotective drugs with minimal side-effects and better efficacies. Natural agents derived from herbs or plants have become unparalleled resources for the discovery of novel drug candidates. Panax ginseng C. A. Meyer, a well-known herbal medicine in China, occupies a very important position in traditional Chinese medicines (TCMs) with a long history of clinical application. Ginsenoside Rd is the active compound in P. ginseng known to have broad-spectrum pharmacological effects to reduce neurological damage that can lead to neurological diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, depression, cognitive impairment, and cerebral ischemia.

PURPOSE

To review and discuss the effects and mechanisms of ginsenoside Rd in the treatment of neurological diseases.

STUDY DESIGN & METHODS

The related information was compiled by the major scientific databases, such as Chinese National Knowledge Infrastructure (CNKI), Elsevier, ScienceDirect, PubMed, SpringerLink, Web of Science, and GeenMedical. Using 'Ginsenoside Rd', 'Ginsenosides', 'Anti-inflammation', 'Antioxidant', 'Apoptosis' and 'Neuroprotection' as keywords, the correlated literature was extracted and conducted from the databases mentioned above.

RESULTS

Through summarizing the existing research progress, we found that the general effects of ginsenoside Rd are anti-inflammatory, antioxidant, anti-apoptosis, inhibition of Ca²⁺ influx and protection of mitochondria, and through these pathways, the compound can inhibit excitatory toxicity, regulate nerve growth factor, and promote nerve regeneration.

CONCLUSION

Ginsenoside Rd is a promising natural neuroprotective agent. This review would contribute to the future development of ginsenoside Rd as a novel clinical candidate drug for treating neurological diseases.

Challenges and Improvements of Novel Therapies for Ischemic Stroke

Stroke is the third most common disease all over the world, which is regarded as a hotspot in medical research because of its high mortality and morbidity. Stroke, especially ischemic stroke, causes severe neural cell death, and no effective therapy is currently available for neuroregeneration after stroke. Although many therapies have been shown to be effective in preclinical studies of ischemic stroke, almost none of them passed clinical trials, and the reasons for most failures have not been well identified. In this review, we focus on several novel methods, such as traditional Chinese medicine, stem cell therapy, and exosomes that have not been used for ischemic stroke till recent decades. We summarize the proposed basic mechanisms underlying these therapies and related clinical results, discussing advantages and current limitations for each therapy emphatically. Based on the limitations such as side effects, narrow therapeutic window, and less accumulation at the injury region, structure transformation and drug combination are subsequently applied, providing a deep understanding to develop effective treatment strategies for ischemic stroke in the near future.

Emerging immune and cell death mechanisms in stroke: Saponins as therapeutic candidates

The complexity of the ischemic cascade is based on the integrated crosstalk of every cell type in the neurovascular unit. Depending on the features of the ischemic insult, several cell death mechanisms are triggered, such as apoptosis, necroptosis, ferroptosis/oxytosis, ETosis or pyroptosis, leading to reactive astrogliosis. However, emerging evidence demonstrates a dual role for the immune system in stroke pathophysiology, where it exerts both detrimental and also beneficial functions. In this review, we discuss the relevance of several cell death modalities and the dual role of the immune system in stroke pathophysiology. We also provide an overview of some emerging immunomodulatory therapeutic strategies, amongst which saponins, which are promising candidates that exert multiple pharmacological effects.

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Several cell death mechanisms coexist in stroke pathophysiology.

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Neurons are more vulnerable to necroptosis than glial cells.

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Inhibitors of receptor-interacting protein kinases and of ferroptosis induce neuroprotection.

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Saponins exert modulatory effects on inflammation and neuronal cell death in stroke.

Protective Effect of Total Panax Notoginseng Saponins on Retinal Ganglion Cells of an Optic Nerve Crush Injury Rat Model

Irreversible loss of retinal ganglion cells (RGCs) is a common pathological feature of various optic nerve degenerative diseases such as glaucoma and ischemic optic neuropathy. Effective protection of RGCs is the key to successful treatment of these diseases. Total Panax notoginseng saponins (TPNS) are the main active component of Panax notoginseng, which has an inhibitory effect on the apoptosis pathway. This study is aimed at assessing the protective effect of TPNS on RGCs of the optic nerve crush (ONC) model of rats and exploring the underlying mechanisms. The intraperitoneal or intravitreal injection of TPNS was used based on the establishment of the rat ONC model. Fifteen days after the injury, the cell membrane fluorescent probe (Fluoro-Gold) was applied to retrograde RGCs through the superior colliculus and obtain the number of surviving RGCs. TUNEL assay was also used to detect the number and density of RGC apoptosis after the ONC model. The expression and distribution of Bcl-2/Bax, c-Jun/P-c-Jun, and P-JNK in the retina were demonstrated by Western blot analysis. After the intervention of TPNS, the rate of cell survival increased in different retinal regions (p < 0.05) and the number of apoptosis cells decreased. Regarding the expression of Bcl-2/Bax, c-Jun/P-c-Jun, and P-JNK-related apoptotic proteins, TPNS can reduce the level of apoptosis and play a role in protecting RGCs (p < 0.05). These findings indicate that topical administration of TPNS can inhibit cell apoptosis and promote RGC survival in the crushed optic nerve.