Ginsenoside Rg1 protects against 6-OHDA-induced toxicity in MES23.5 cells via Akt and ERK signaling pathways

Iron metabolism: An emerging therapeutic target underlying the anti-Alzheimer's disease effect of ginseng

Finding neuroprotective drugs with fewer side effects and more efficacy has become a major problem as the global prevalence of Alzheimer's disease (AD) rises. Natural drugs have risen to prominence as potential medication candidates. Ginseng has a long history of use in China, and it has a wide range of pharmacological actions that can help with neurological issues. Iron loaded in the brain has been linked to AD pathogenesis. We reviewed the regulation of iron metabolism and its studies in AD and explored how ginseng might regulate iron metabolism and prevent or treat AD. Researchers utilized network pharmacology analysis to identify key factive components of ginseng that protect against AD by regulating ferroptosis. Ginseng and its active ingredients may benefit AD by regulating iron metabolism and targeting ferroptosis genes to inhibit the ferroptosis process. The results present new ideas for ginseng pharmacological studies and initiatives for further research into AD-related drugs. To provide comprehensive information on the neuroprotective use of ginseng to modulate iron metabolism, reveal its potential to treat AD, and provide insights for future research opportunities.

Multifaceted role of polyphenols in the treatment and management of neurodegenerative diseases

Neurodegenerative diseases (NDDs) are conditions that cause neuron structure and/or function to deteriorate over time. Genetic alterations may be responsible for several NDDs. However, a multitude of physiological systems can trigger neurodegeneration. Several NDDs, such as Huntington's, Parkinson's, and Alzheimer's, are assigned to oxidative stress (OS). Low concentrations of reactive oxygen and nitrogen species are crucial for maintaining normal brain activities, as their increasing concentrations can promote neural apoptosis. OS-mediated neurodegeneration has been linked to several factors, including notable dysfunction of mitochondria, excitotoxicity, and Ca²⁺ stress. However, synthetic drugs are commonly utilized to treat most NDDs, and these treatments have been known to have side effects during treatment. According to providing empirical evidence, studies have discovered many occurring natural components in plants used to treat NDDs. Polyphenols are often safer and have lesser side effects. As, epigallocatechin-3-gallate, resveratrol, curcumin, quercetin, celastrol, berberine, genistein, and luteolin have p-values less than 0.05, so they are typically considered to be statistically significant. These polyphenols could be a choice of interest as therapeutics for NDDs. This review highlighted to discusses the putative effectiveness of polyphenols against the most prevalent NDDs.

Role of ginseng in the neurovascular unit of neuroinflammatory diseases focused on the blood-brain barrier

Ginseng has long been considered as an herbal medicine. Recent data suggest that ginseng has anti-inflammatory properties and can improve learning- and memory-related function in the central nervous system (CNS) following the development of CNS neuroinflammatory diseases such as Alzheimer's disease, cerebral ischemia, and other neurological disorders. In this review, we discuss the role of ginseng in the neurovascular unit, which is composed of endothelial cells surrounded by astrocytes, pericytes, microglia, neural stem cells, oligodendrocytes, and neurons, especially their blood-brain barrier maintenance, anti-inflammatory effects and regenerative functions. In addition, cell-cell communication enhanced by ginseng may be attributed to regeneration via induction of neurogenesis and angiogenesis in CNS diseases. Thus, ginseng may have therapeutic potential to exert cognitive improvement in neuroinflammatory diseases such as stroke, traumatic brain injury, multiple sclerosis, Parkinson's disease, and Alzheimer's disease.

Ginsenoside Rg1 exerts neuroprotective effects in 3-nitropronpionic acid-induced mouse model of Huntington's disease via suppressing MAPKs and NF-κB pathways in the striatum

Huntington's disease (HD) is one of main neurodegenerative diseases, characterized by striatal atrophy, involuntary movements, and motor incoordination. Ginsenoside Rg1 (Rg1), an active ingredient in ginseng, possesses a variety of neuroprotective effects with low toxicity and side effects. In this study, we investigated the potential therapeutic effects of Rg1 in a mouse model of HD and explored the underlying mechanisms. HD was induced in mice by injection of 3-nitropropionic acid (3-NP, i.p.) for 4 days. From the first day of 3-NP injection, the mice were administered Rg1 (10, 20, 40 mg·kg^-1, p.o.) for 5 days. We showed that oral pretreatment with Rg1 alleviated 3-NP-induced body weight loss and behavioral defects. Furthermore, pretreatment with Rg1 ameliorated 3-NP-induced neuronal loss and ultrastructural morphological damage in the striatum. Moreover, pretreatment with Rg1 reduced 3-NP-induced apoptosis and inhibited the activation of microglia, inflammatory mediators in the striatum. We revealed that Rg1 exerted neuroprotective effects by suppressing 3-NP-induced activation of the MAPKs and NF-κΒ signaling pathways in the striatum. Thus, our results suggest that Rg1 exerts therapeutic effects on 3-NP-induced HD mouse model via suppressing MAPKs and NF-κΒ signaling pathways. Rg1 may be served as a novel therapeutic option for HD.

Cadmium Impairs Autophagy Leading to Apoptosis by Ca2+-Dependent Activation of JNK Signaling Pathway in Neuronal Cells

Autophagy, a process for self-degradation of intracellular components and dysfunctional organelles, is closely related with neurodegenerative diseases. It has been shown that cadmium (Cd) induces neurotoxicity partly by impairing autophagy. However, the underlying mechanism is not fully elucidated. In this study, we show that Cd induced expansion of autophagosomes with a concomitant abnormal expression of autophagy-related (Atg) proteins in PC12 cells and primary murine neurons. 3-MA, a classical inhibitor of autophagy, attenuated Cd-induced expansion of autophagosomes and apoptosis in the cells. Further investigation demonstrated that Cd activated JNK pathway contributing to autophagosome expansion-dependent neuronal apoptosis. This is supported by the findings that pharmacological inhibition of JNK with SP600125 or expression of dominant negative c-Jun markedly attenuated Cd-induced expansion of autophagosomes and abnormal expression of Atg proteins, as well as apoptosis in PC12 cells and/or primary neurons. Furthermore, we noticed that chelating intracellular free Ca²⁺ ([Ca²⁺]_i) with BAPTA/AM profoundly blocked Cd-elicited activation of JNK pathway and consequential expansion of autophagosomes, abnormal expression of Atg proteins, and apoptosis in the neuronal cells. Similar events were also seen following prevention of [Ca²⁺]_i elevation with EGTA or 2-APB, implying a Ca²⁺-dependent mechanism involved. Taken together, the results indicate that Cd impairs autophagy leading to apoptosis by Ca²⁺-dependent activation of JNK signaling pathway in neuronal cells. Our findings highlight that manipulation of intracellular Ca²⁺ level and/or JNK activity to ameliorate autophagy may be a promising intervention against Cd-induced neurotoxicity and neurodegeneration.

Hormesis and Ginseng: Ginseng Mixtures and Individual Constituents Commonly Display Hormesis Dose Responses, Especially for Neuroprotective Effects

This paper demonstrates that ginseng mixtures and individual ginseng chemical constituents commonly induce hormetic dose responses in numerous biological models for endpoints of biomedical and clinical relevance, typically providing a mechanistic framework. The principal focus of ginseng hormesis-related research has been directed toward enhancing neuroprotection against conditions such as Alzheimer's and Parkinson's Diseases, stroke damage, as well as enhancing spinal cord and peripheral neuronal damage repair and reducing pain. Ginseng was also shown to reduce symptoms of diabetes, prevent cardiovascular system damage, protect the kidney from toxicities due to immune suppressant drugs, and prevent corneal damage, amongst other examples. These findings complement similar hormetic-based chemoprotective reports for other widely used dietary-type supplements such as curcumin, ginkgo biloba, and green tea. These findings, which provide further support for the generality of the hormetic dose response in the biomedical literature, have potentially important public health and clinical implications.

Upstream regulators of phosphoinositide 3-kinase and their role in diseases

Phosphoinositide 3-kinase (PI3K), a crucial signaling molecule, is regulated by various upstream regulators. Traditionally, receptor tyrosine kinases and G protein-coupled receptor are regarded as its principle upstream regulators; however, recent reports have indicated that spleen tyrosine kinase, β-arrestin2, Janus kinase, and RAS can also perform this role. Dysregulation of PI3K is common in the progression of various diseases, including, but not limited to, tumors, Alzheimer's disease, Parkinson's disease, rheumatoid arthritis, and acute myelogenous leukemia. The aim of this review is to provide a perspective on PI3K-related diseases examining both the classical and nonclassical upstream regulators of PI3K in detail.

Analytical methods and biological activities of Panax notoginseng saponins: Recent trends

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng (Burk.) F. H. Chen, also called Sanqi, is a widely used traditional Chinese medicine, which has long history used as herbal medicines. It is currently an important medicinal material in China, holding the first place in the sale volume of the whole patent medicines market in China, and the market size of the single species has exceeded 10 billion yuan. In addition, P. notoginseng is an important constituent part of many famous Chinese patent medicines, such as Compound Danshen Dripping Pills and Yunnan Baiyao. P. notoginseng saponins (PNSs), which are the major active components of P. notoginseng, are a kind of chemical mixture containing different dammarane-type saponins. Many studies show that PNSs have been extensively used in medical research or applications, such as atherosclerosis, diabetes, acute lung injury, cancer, and cardiovascular diseases. In addition, various PNS preparations, such as injections and capsules, have been made commercially available and are widely applied in clinical practice.

AIM OF THE REVIEW

Since the safety and efficacy of compounds are related to their qualitative and quantitative analyses, this review briefly summarizes the analytic approaches for PNSs and their biological effects developed in the last decade.

METHODOLOGY

This review conducted a systematic search in electronic databases, such as Pubmed, Google Scholar, SciFinder, ISI Web of Science, and CNKI, since 2009. The information provided in this review is based on peer-reviewed papers and patents in either English or Chinese.

RESULTS

At present, the chromatographic technique remains the most extensively used approach for the identification or quantitation of PNSs, coupled with different detectors, among which the difference mainly lies in their sensitivity and specificity for analyzing various compounds. It is well-known that PNSs have traditionally strong activity on cardiovascular diseases, such as atherosclerosis, intracerebral hemorrhage, or brain injury. The recent studies showed that PNSs also responded to osteoporosis, cancers, diabetes, and drug toxicity. However, some other studies also showed that some PNSs injections and special PNS components might lead to some biological toxicity under certain dosages.

CONCLUSION

This review may be used as a basis for further research in the field of quantitative and qualitative analyses, and is expected to provide updated and valuable insights into the potential medicinal applications of PNSs.

Ginsenoside Rg1 protects against hind-limb ischemia reperfusion induced lung injury via NF-κB/COX-2 signaling pathway

BACKGROUND/AIMS

Ginsenoside Rg1 is regarded as the primary bioactive ingredient in Panax notoginseng that has been well recognized for its protective effects against ischemia/reperfusion (IR) injury. However, the mechanisms still remain elusive. Our study aims to investigate the effects of Rg1 against lung injury induced by hind-limb IR in rats.

METHODS

Twenty-four Sprague Dawley rats were randomly submitted to sham operation (SM group), hind-limb IR (IR group), hind-limb IR + Rg1 (Rg1 group), and hind-limb IR + Pro-DTC group (PD group). All the rats except those in SM group were subjected to 3 h of ischemia followed by 6 h of reperfusion, and extra intravenous Rg1 and pyrrolidine dithiocarbamate (Pro-DTC), a selective inhibitor of nuclear factor kappa B (NF-κB), was administered intravenously before ischemia in the Rg1 and PD group, respectively. The activities of myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT), as well as protein expressions of NF-κB p65 and cyclooxygenases-2 (COX-2) in lung tissue, and thromboxane B2 (TXB2) and 6-keto-ProstaglandinF_1α (6-keto-PGF_1α) levels in bronchoalveolar lavage (BAL) fluid were detected. Morphological changes, index of quantitative assessment of histologic lung injury (IQA), apoptosis index (AI) and lung Wet/Dry ratio were also evaluated.

RESULTS

The levels of Wet/Dry ratio, IQA, AI, activities of MPO and 6-keto-PGF_1α/TXB₂ ratio were increased, and NF-κB p65 and COX-2 protein expression were upregulated, while SOD and CAT levels were decreased in lung tissue in IR group as compared with SM group (p < 0.05), all the alterations could be significantly reversed by Rg1 or Pro-DTC pretreatment (p < 0.05). And Rg1 and Pro-DTC also significantly attenuated the pulmonary histological abnormalities induced by IR.

CONCLUSION

Ginsenoside Rg1 potentially attenuated lung injury induced by hind-limb IR by regulating NF-κB/COX-2 signaling pathway.

Ginsenoside Rg1 activates ligand-independent estrogenic effects via rapid estrogen receptor signaling pathway

Background

Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor (ER) via mitogen-activated protein kinase–mediated pathway. Our study aimed to delineate the mechanisms by which Rg1 activates the rapid ER signaling pathways.

Methods

ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidney HEK293 cells were treated with Rg1 (10⁻¹²M, 10⁻⁸M), 17ß-estradiol (10⁻⁸M), or vehicle. Immunoprecipitation was conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or their inhibitors were applied.

Results

Rg1 rapidly induced ERα translocation to plasma membrane via caveolin-1 and the formation of signaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator of nongenomic activity of ER (MNAR), ERα, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase (MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interfering RNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in these cells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor (EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). The increase in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could be abolished by G15.

Conclusion

Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containing signalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independently and exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogen receptor.

Semi-synthesis of Twelve Known 20Z/E Pseudo-Ginsenosides and Their Comparative Study of Antioxidative Activity in Free Radical Induced Hemolysis of Rabbit Erythrocytes

Twelve pseudo-ginsenosides were synthesized under a mild condition, via a simple three-step called acetylation, elimination-addition and saponification. The inhibitory effects of these twelve pseudo-ginsenosides were screened on the hemolysis of rabbit erythrocytes caused by 2,2'-azobis (2-amidinopropane hydrochloride) (AAPH). It was found that the IC₅₀ values followed the sequence of (20Z) pseudo-protopanaxatriol (pseudo-PPT)<(20Z) pseudo-protopanaxadiol (pseudo-PPD)<(20Z) pseudo-Rh2<(20E) pseudo-PPT<(20E) pseudo-PPD<(20E) pseudo-Rh2<(20Z) pseudo-Rg2<(20E) pseudo-Rg2<Rb1<(20Z) pseudo-Rh1<Rg2<(20E) pseudo-Rh1. These compounds can be divided into three groups: accelerate the hemolysis group (7, 8), weak group (2, 11, 12) and strong group (others). Moreover, we also find that most of the Z configuration has better antioxidative activity than E configuration and the number and type of sugar moieties to the ring of triterpene dammarane influence the antioxidative activity.

Neuroprotective properties of icariin in MPTP-induced mouse model of Parkinson's disease: Involvement of PI3K/Akt and MEK/ERK signaling pathways

BACKGROUND

Epimedium sagittatum is a traditional Chinese herb normally which is used to treat the osteoporosis, cardiovascular dysfunction, and to improve neurological and sexual function in China, Korea and Japan. Icariin is the major active ingredient in Epimedium sagittatum. In the present research, we examined the neuroprotective effects of icariin on dopaminergic neurons and the possible mechanisms in a mouse model of Parkinson's disease (PD).

METHODS

Ovariectomized PD mice were treated with vehicle or icariin (3 days before MPTP injections) with or without the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 or mitogen-activated protein kinase kinase (MEK) inhibitor PD98059. The dopamine (DA) content in the striatum was studied by HPLC. Western blot was used to determine the protein expressions of Bcl-2, Bax and Caspase 3 in the striatum. The numbers of tyrosine hydroxylase-immunoreactive (TH-IR) neurons in the substantial nigra pars compacta (SNpc) were assessed by immunohistochemistry. The activation of Akt and ERK by icariin were detected in doparminergic MES23.5 cells.

RESULTS

Icariin pretreatment could ameliorate the decreased striatum DA content and the loss of TH-IR neurons in the SNpc induced by MPTP. The MPTP-induced changes of Bcl-2, Bax and caspase 3 protein expressions in the striatum could be reversed by icariin pretreatment. Blockade of PI3K/Akt or MEK/ERK signaling pathway by LY294002 or PD98059 could attenuate the increase of DA content in the striatum and TH-IR in the SNpc induced by icariin in PD mice model. Additionally, icariin treatment alone significantly induced the phosphorylation of Akt and ERK in a time dependent pattern in dopaminergic MES 23.5 cells. These effects were abolished by co-treatment with LY294002 or PD98059.

CONCLUSION

These data demonstrated that icariin has neuroprotective effect on dopaminergic neurons in PD mice model and the potential mechanisms might be related to PI3K/Akt and MEK/ERK pathways.

Involvement of IGF-1 receptor signaling pathway in the neuroprotective effects of Icaritin against MPP(+)-induced toxicity in MES23.5 cells

Icaritin, a natural derivative of Icariin, is the major bioactive component of Epimedium Genus. The present study tested the hypothesis that the neuroprotective effects of Icaritin against 1-Methyl-4-phenylpyridinium ion (MPP(+))-induced toxicity involved activation of the insulin-like growth factor-1 receptor (IGF-1R) signaling pathway in MES23.5 cells. Our results revealed that Icaritin pretreatment attenuated the MPP(+)-induced decrease of cell viability in a dose-dependent fashion. Co-pretreatment with phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002, mitogen-activated protein kinase (MEK) inhibitor PD98059 or IGF-1 receptor antagonist JB-1 could completely block the protective effects of Icaritin. Moreover, Icaritin pretreatment down-regulated MPP(+)-induced increase of Bax/Bcl-2 ratio transcriptionally and post-transcriptionally. Further study revealed that Icaritin pretreatment could restore the decreased protein expression of Akt and extracellular signal-regulated kinase 1/2 (ERK1/2) induced by MPP(+) and these effects could be completely abolished by LY294002, PD98059 or JB-1. Additionally, Icaritin treatment alone time-dependently enhanced the phosphorylation of Akt and ERK1/2 in MES23.5 cells. The activation of Akt and ERK1/2 by Icaritin could be completely blocked by JB-1, LY294002 or PD98059. Taken together, our data demonstrate that IGF-1 receptor mediated activation of PI3K/Akt and MEK/ERK1/2 signaling pathways are involved in the protective effects of Icaritin against MPP(+)-induced toxicity in MES23.5 cells.

Two New Triterpenoid Saponins from the Structural Modification of Pseudoginsenoside-F11 and their Cytotoxic Activities

Two ginsenoside derivatives (1, 2) along with 2 known ginsenosides (3, 4) were isolated from the acid hydrolysis products of pseudoginsenoside-F11. Their structures were elucidated on the basis of spectroscopic analyses, including 1D, 2D NMR and HR-ESI-MS. Among them, (12 R, 20 S, 24 S)-20, 24; 12, 24-diepoxy-dammarane-3β, 6α-diol (1) and (20 R, 24 R)-dammar-20, 24-epoxy-3β, 6α, 12β, 25-tetraol (2) were identified as new triterpenoid saponins. They were subjected to assay for cytotoxic activities against six human tumor cells lines.

Notoginsenoside Rb1 inhibits activation of ERK and p38 MAPK pathways induced by hypoxia and hypercapnia

The aim of the present study was to investigate the effect of notoginsenoside Rb1 (Rb1) on the ERK and p38 MAPK pathways in primary cultured pulmonary arterial smooth muscle cells (PASMCs) exposed to hypoxia and hypercapnia, in order to elucidate the mechanism underlying the effect of Rb1 on hypoxia and hypercapnia-induced pulmonary vasoconstriction (HHPV). PASMCs were isolated from Sprague-Dawley rats. The cells were divided into five groups: Normal (N), hypoxia and hypercapnia (H), Rb_L, Rb_M and Rb_H groups. N group cells were cultured under 5% CO₂ and 21% O₂. H, Rb_L, Rb_M and Rb_H groups were cultured under 6% CO₂ and 1% O₂. Prior to the hypoxia and hypercapnia exposure, Rb_L, Rb_M and Rb_H groups were treated with 8, 40 and 100 mg/ml Rb1 for 30 min, respectively. Phosphorylated extracellular signal-regulated kinase (P-ERK) and P-p38 protein, and ERK1/2 and p38 mRNA expression levels were detected using western blot and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analyses, respectively. The correlations between P-ERK protein and ERK1/2 mRNA, and between P-p38 protein and p38 mRNA were evaluated. Results of western blot and RT-PCR showed hypoxia and hypercapnia increased P-ERK and P-p38 protein, and ERK1/2 mRNA, respectively (P<0.05). Rb1 suppressed the increased P-ERK and P-p38 protein, and ERK1/2 and p38 mRNA by hypoxia and hypercapnia (P<0.05). P-ERK protein was positively correlated with ERK1 (r=0.5, P<0.01) and ERK2 mRNA (r=0.977, P<0.01). P-p38 protein was positively correlated with p38 mRNA (r=0.884, P<0.01). Thus, the present results indicate that Rb1 may ameliorate HHPV by suppressing ERK and p38 pathways. The study provides an experimental basis for investigating the clinical use of Rb1 in the management of HHPV-related disorders.

Glucocorticoid receptor is involved in the neuroprotective effect of ginsenoside Rg1 against inflammation-induced dopaminergic neuronal degeneration in substantia nigra

Accumulating clinical and experimental evidence suggests that chronic neuroinflammation is associated with dopaminergic neuronal death in Parkinson's disease (PD). Ginsenoside Rg1, the most active components of ginseng, possesses a variety of biological effects on the central nervous system, cardiovascular system and immune system. The present study aimed to evaluate the protective effects of ginsenoside Rg1 on lipopolysaccharide (LPS)-induced microglia activation and dopaminergic neuronal degeneration in rat substantia nigra (SN) and its potential mechanisms. Treatment with Rg1 could ameliorate the apomorphine-induced rotational behavior in LPS-lesioned rats. GR antagonist RU486 partly abolished the protective effect of Rg1. Rg1 treatment significantly attenuated LPS-induced loss of tyrosin hydroxlase (TH) positive neurons in substantial nigra par compacta (SNpc) and decreased content of dopamine (DA) and its metabolites in striatum of the lesioned side. Meanwhile, Rg1 significantly inhibited LPS-induced microglial activation and production of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and nitric oxide (NO). These effects were abolished by co-treatment with RU486. In addition, Rg1 treatment significantly inhibited the LPS-induced phosphorylation of IκB, extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) in the lesioned side of substantial nigra. These effect could be also partly blocked by RU486. Taken together, these data indicate that Rg1 has protective effects on mesencephalic dopaminergic neurons from LPS-induced microglia inflammation. GR signaling pathway might be involved in the anti-inflammatory effect of Rg1.

Recent trends in the development of nanophytobioactive compounds and delivery systems for their possible role in reducing oxidative stress in Parkinson's disease models

Oxidative stress plays a very critical role in neurodegenerative diseases, such as Parkinson's disease (PD), which is the second most common neurodegenerative disease among elderly people worldwide. Increasing evidence has suggested that phytobioactive compounds show enhanced benefits in cell and animal models of PD. Curcumin, resveratrol, ginsenosides, quercetin, and catechin are phyto-derived bioactive compounds with important roles in the prevention and treatment of PD. However, in vivo studies suggest that their concentrations are very low to cross blood-brain barrier thereby it limits bioavailability, stability, and dissolution at target sites in the brain. To overcome these problems, nanophytomedicine with the controlled size of 1-100 nm is used to maximize efficiency in the treatment of PD. Nanosizing of phytobioactive compounds enhances the permeability into the brain with maximized efficiency and stability. Several nanodelivery techniques, including solid lipid nanoparticles, nanostructured lipid carriers, nanoliposomes, and nanoniosomes can be used for controlled delivery of nanobioactive compounds to brain. Nanocompounds, such as ginsenosides (19.9 nm) synthesized using a nanoemulsion technique, showed enhanced bioavailability in the rat brain. Here, we discuss the most recent trends and applications in PD, including 1) the role of phytobioactive compounds in reducing oxidative stress and their bioavailability; 2) the role of nanotechnology in reducing oxidative stress during PD; 3) nanodelivery systems; and 4) various nanophytobioactive compounds and their role in PD.

Ginsenoside Rg1 protects against transient focal cerebral ischemic injury and suppresses its systemic metabolic changes in cerabral injury rats

Ginsenoside Rg1 (GR), a major bioactive compound of traditional Chinese medicine, such as Panax ginseng or Radix Notoginseng, has been shown to exert neuroprotective effects against ischemic stroke. However, pharmacokinetic studies have suggested that GR could not be efficiently transported through the blood-brain barrier. The mechanism by which GR attenuates cerebral ischemic injury in vivo remains largely unknown. Therefore, this study explored potential neuro-protective effects of GR through its systemic metabolic regulating mechanism by using mass spectrometry-based metabolomic profiling. Rats with middle cerebral artery occlusion (MCAO) were treated with GR intravenously. Their metabolic profiles in serum were measured by gas chromatography coupled with mass spectrometry on 1 and 3 days after MCAO. GR exhibited a potent neuro-protective effect by significantly decreasing the neurological scores and infarct volume in the MCAO rats. Moreover, 18 differential metabolites were tentatively identified, all of which appeared to correlate well with these disease indices. Our findings suggested that GR carries a therapeutic potential in stroke possibly through a feed-back mechanism by regulating systematic metabolic mediation.

Neuroprotective effect of water extract of Panax ginseng on corticosterone-induced apoptosis in PC12 cells and its underlying molecule mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Panax ginseng C.A. Meyer (Family Araliaceae) is an important medicinal plant which has been employed as a panacea for more than 2,000 years in China. It has the actions of invigorating primordial qi, recovering pulse and desertion, engendering liquid, and calming spirit. The water extract of Panax ginseng (WEG) has been used to treat kinds of central nervous system disorders, such as depression, insomnia, Alzheimer׳s disease and Parkinson׳s disease. Our previous work has demonstrated that WEG possessed antidepressant-like activities in both acute and chronic stress models of depression. Nevertheless, there are no studies on the cytoprotection and potential mechanisms of WEG on corticosterone-induced apoptosis. The present study focuses on cytoprotection against corticosterone-induced neurotoxicity in PC12 cells and its underlying molecule mechanisms of the antidepressant-like effect of WEG.

MATERIALS AND METHODS

The PC12 cells were treated with 250 μmol/L corticosterone in the absence or presence of WEG for 24h, then 3-(4,5-dimethy thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) detection, Hoechst33342 staining and TUNEL staining were investigated to confirm the neuroprotection of WEG. Then, mitochondrial permeability transition pore (mPTP), mitochondrial membrane potential (MMP), intracellular Ca(2+) ([Ca(2+)]i), reactive oxygen species (ROS) concentration, and the expression level of glucocorticoid receptor (GR), heat shock protein 90 (Hsp90), histone deactylase 6 (HDAC6), glucose-regulated protein 78 (GRP78), growth arrest and DNA damage inducible protein 153 (GADD153), X-box DNA-binding protein-1 (XBP-1), caspase-12, cytochrome C, inhibitor of caspase-activated deoxyribonuclease (ICAD), caspase-3 and caspase-9 were assessed by Western Blot analysis to understand the molecule mechanisms of neuroprotection of WEG.

RESULTS

WEG partly reversed corticosterone-induced damage in PC12 cells, which increased cell viability, decreased LDH release, and attenuated corticosterone-induced apoptosis as compared with the corticosterone-treated group. Mechanistically, compared with the corticosterone-treated group, WEG strongly attenuated [Ca(2+)]i overload and ROS level, and restored mitochondrial function, including mPTP and MMP. Furthermore, WEG strongly up-regulated the expression of GR and HDAC6, and down-regulated the expression of Hsp90, cytochrome C, ICAD, caspase-3, caspase-9 as well as endoplasmic reticulum (ER) stress-related proteins, such as GADD153, GRP78, XBP-1, and caspase-12.

CONCLUSION

WEG possessed neuroprotection against corticosterone-induced damage in PC12 cells, and the underlying molecule mechanisms was depended on the intervening of HDAC6 and HSP90 of the GR-related function proteins, and subsequent restoration of ER and mitochondria functions.

Protection of ginsenoside Rg1 on chondrocyte from IL-1β-induced mitochondria-activated apoptosis through PI3K/Akt signaling

Chondrocyte apoptosis is closely related to the development and progression of osteoarthritis. Ginsenoside Rg1 protects cells by antagonizing apoptosis. This study aimed to investigate the protective effect of Rg1 on interleukin 1β (IL-1β)-induced chondrocyte apoptosis and the underlying molecular mechanisms. Chondrocytes were harvested from the joints of 1-week-old Sprague-Dawley rats. After treated with 10 μg/mL Rg1 for 2 h, the chondrocytes were cultured with 10 ng/mL IL-1β to induce cytotoxicity. Cell viability was assessed with MTT assays. Annexin V/propidium iodide staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling were used to detect chondrocyte apoptosis. The contents of total Akt, phosphorylated Akt (p-Akt), Bcl-2, Bax, and cytochrome C (Cyt c) were determined by Western blotting assay. A quantitative colorimetric assay was used to determine caspase-3 activity. Our present findings have shown that pre-treatment of chondrocytes with Rg1 reduces IL-1β induced cytotoxicity/apoptosis. Rg1 pretreatment also decreases the activity of IL-1β that reduces expression of Bcl-2 and level of p-Akt, and increases Bax activity, Cyt c release, and caspase-3 activation. It also reverses the activity of IL-1β that reduces the expression of tissue inhibitor of metalloproteinase-1 expression and increased the synthesis of matrix metalloproteinase-13, with the net effect of inhibiting extracellular matrix degradation. These results indicate that Rg1 may protect chondrocytes from IL-1β-induced apoptosis via the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, through preventing caspase-3 release.

Neuroprotective potentials of neurotrophin rich olfactory ensheathing cell's conditioned media against 6OHDA-induced oxidative damage

On the basis of recent reports, we propose that impaired neurotrophin signaling (PI3k/Akt), low antioxidant levels, and generation of reactive oxygen species (ROS) conjointly participate in the progressive events responsible for the dopaminergic cell loss in Parkinson's disease (PD). In the present study we tried to target these deficits collectively through multiple neurotrophic factors (NTFs) support in the form of Olfactory Ensheathing Cell's Conditioned Media (OEC CM) using human SH-SY5Y neuroblastoma cell line exposed to 6 hydroxydopamine (6OHDA). 6OHDA exposure induced, oxidative stress-mediated apoptotic cell death viz. enhanced ROS generation, diffused cytosolic cytochrome c (cyt c), impaired Bcl-2: Bax levels along with decrease in GSH content. These changes were accompanied by loss in Akt phosphorylation and TH levels in SH-SY5Y cells. OEC CM significantly checked apoptotic cell death by preserving pAkt levels which coincided with enhanced GSH and suppressed oxidative injury. Functional integrity of OEC CM supported cells was evident by maintained tyrosine hydroxylase (TH) expression. Intercepting Akt signaling by specific inhibitor LY294002 blocked the protective effect. Taken together our findings provide important evidence that the key to protective effect of multiple NTF support via OEC CM is enhanced Akt survival signaling which promotes antioxidant defense leading to suppression of oxidative damage.

The beneficial effect of ginsenoside Rg1 on Schwann cells subjected to hydrogen peroxide induced oxidative injury

Ginsenoside Rg1 (GRg1) has been considered to have therapeutic potential in promoting peripheral nerve regeneration and functional recovery after sciatic nerve injuries. However, the mechanism underlying the beneficial effect of GRg1 on peripheral nerve regeneration is currently unclear. The possible effect of GRg1 on Schwann cells (SCs), which were subjected to oxidative injury after nerve injury, might contribute to the beneficial effect of GRg1 on nerve regeneration. The present study was designed to investigate the potential beneficial effect of GRg1 on SCs exposed to oxidative injury. The oxidative injury to SCs was induced by hydrogen peroxide. The effect of GRg1 (50 μM) on SCs exposed to oxidative injury was measured by the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT) in SCs. The cell number and cell viability of SCs were evaluated through fluorescence observation and MTT assay. The apoptosis of SCs induced by oxidative injury was evaluated by an apoptosis assay. The expression and secretion of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were evaluated using RT-PCR, Western blotting, and an ELISA method. We found that GRg1 significantly up-regulated the level of SOD, GSH and CAT, and decreased the level of MDA in SCs treated with hydrogen peroxide. In addition, GRg1 has been shown to be able to inhibit the proapoptotic effect of hydrogen peroxide, as well as inhibit the detrimental effect of hydrogen peroxide on cell number and cell viability. Furthermore, GRg1 also increased the mRNA levels, protein levels and secretion of NGF and BDNF in SCs after incubation of hydrogen peroxide. Further study showed that preincubation with H89 (a PKA inhibitor) significantly inhibited the effects induced by hydrogen peroxide, indicating that the PKA pathway might be involved in the antioxidant effect and neurotrophic factors (NTFs) promoting effect of GRg1. In addition, a short-term in vivo study was performed to confirm and validate the antioxidant effect and nerve regeneration-promoting effect of GRg1 in a sciatic crush injury model in rats. We found that GRg1 significantly increased SOD, CAT and GSH, decreased MDA, as well as promoted nerve regeneration after crush injury. In conclusion, the present study showed that GRg1 is capable of helping SCs recover from the oxidative insult induced by hydrogen peroxide, which might account, at least in part, for the beneficial effect of GRg1 on nerve regeneration.

A comprehensive review of the therapeutic and pharmacological effects of ginseng and ginsenosides in central nervous system

Ginseng is one of the most widely used herbal medicines in human. Central nervous system (CNS) diseases are most widely investigated diseases among all others in respect to the ginseng’s therapeutic effects. These include Alzheimer’s disease, Parkinson’s disease, cerebral ischemia, depression, and many other neurological disorders including neurodevelopmental disorders. Not only the various types of diseases but also the diverse array of target pathways or molecules ginseng exerts its effect on. These range, for example, from neuroprotection to the regulation of synaptic plasticity and from regulation of neuroinflammatory processes to the regulation of neurotransmitter release, too many to mention. In general, ginseng and even a single compound of ginsenoside produce its effects on multiple sites of action, which make it an ideal candidate to develop multi-target drugs. This is most important in CNS diseases where multiple of etiological and pathological targets working together to regulate the final pathophysiology of diseases. In this review, we tried to provide comprehensive information on the pharmacological and therapeutic effects of ginseng and ginsenosides on neurodegenerative and other neurological diseases. Side by side comparison of the therapeutic effects in various neurological disorders may widen our understanding of the therapeutic potential of ginseng in CNS diseases and the possibility to develop not only symptomatic drugs but also disease modifying reagents based on ginseng.

Salsolinol induced apoptotic changes in neural stem cells: amelioration by neurotrophin support

Salsolinol (SAL), a catechol isoquinoline has invited considerable attention due to its structural similarity with dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Its high endogenous presence in Parkinsonian brain implicated its possible association with the disease process. SAL is also present in alcohol beverages and certain food materials and can get access to brain especially in conditions of immature or impaired BBB. Besides this, the effect of SAL on neural stem cells (NSCs) which are potential candidates for adult neurogenesis and transplantation mediated rejuvenating attempts for Parkinson's disease (PD) brain has not been known so far. NSCs in both the cases have to overcome suppressive cues of diseased brain for their survival and function. In this study we explored the toxicity of SAL toward NSCs focusing on apoptosis and status of PI3K survival signaling. NSCs cultured from embryonic day 11 rat fetal brain including those differentiated to TH(+ve) colonies, when challenged with SAL (1-100μM), elicited a concentration and time dependent cell death/loss of mitochondrial viability. 10μM SAL on which significant mitochondrial impairment initiated was further used to study mechanism of toxicity. Morphological impairment, enhanced TUNEL positivity, cleaved caspase-3 and decreased Bcl-2:Bax suggested apoptosis. Sal toxicity coincided with reduced pAkt level and its downstream effectors: pCREB, pGSK-3β, Bcl-2 and neurotrophins GDNF, BDNF suggesting repressed PI3K/Akt signaling. Multiple neurotrophic factor support in the form of Olfactory Ensheathing Cell's Conditioned Media (OEC CM) potentially protected NSCs against SAL through activating PI3K/Akt pathway. This was confirmed on adding LY294002 the PI3K inhibitor which abolished the protection. We inferred that SAL exerts substantial toxicity toward NSCs. These findings will lead to better understanding of endogenous threats that might affect the fate of transplanted NSCs and their probable antidotes.

Korean Red Ginseng Extract Attenuates 3-Nitropropionic Acid-Induced Huntington's-Like Symptoms

Korean red ginseng (KRG) possesses neuroprotective activity. However, the potential neuroprotective value of KRG for the striatal toxicity is largely unknown. We investigated whether KRG extract (KRGE) could have a neuroprotective effect in a 3-nitropropionic acid- (3-NP) induced (i.p.) Huntington's disease (HD) model. KRGE (50, 100, and 250 mg/kg/day, p.o.) was administrated 10 days before 3-NP injection (pre-administration), from the same time with 3-NP injection (co-administration), or from the peak point of neurological impairment by 3-NP injection (post-administration). Pre-administration of KRGE produced the greatest neuroprotective effect in this model. Pre-administration of KRGE significantly decreased 3-NP-induced neurological impairment, lethality, lesion area, and neuronal loss in the 3-NP-injected striatum. KRGE attenuated microglial activation and phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signal pathway. KRGE also reduced the level of mRNA expression of tumor necrosis factor-alpha, interleukin- (IL-) 1β, IL-6, inducible nitric oxide synthase, and OX-42. Interestingly, the intrathecal administration of SB203580 (a p38 inhibitor) or PD98059 (an inhibitor of MAPK Kinase, MEK) increased the survival rate in the 3-NP-induced HD model. Pre-administration of KRGE may effectively inhibit 3-NP-induced striatal toxicity via the inhibition of the phosphorylation of MAPKs and NF-κB pathways, indicating its therapeutic potential for suppressing Huntington's-like symptoms.

Nutraceuticals and their preventive or potential therapeutic value in Parkinson's disease

Parkinson's disease (PD) is the second most common aging-related disorder in the world, after Alzheimer's disease. It is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta and other parts of the brain, leading to motor impairment, cognitive impairment, and dementia. Current treatment methods, such as L-dopa therapy, are focused only on relieving symptoms and delaying progression of the disease. To date, there is no known cure for PD, making prevention of PD as important as ever. More than a decade of research has revealed a number of major risk factors, including oxidative stress and mitochondrial dysfunction. Moreover, numerous nutraceuticals have been found to target and attenuate these risk factors, thereby preventing or delaying the progression of PD. These nutraceuticals include vitamins C, D, E, coenzyme Q10, creatine, unsaturated fatty acids, sulfur-containing compounds, polyphenols, stilbenes, and phytoestrogens. This review examines the role of nutraceuticals in the prevention or delay of PD as well as the mechanisms of action of nutraceuticals and their potential applications as therapeutic agents, either alone or in combination with current treatment methods.

Anti-Parkinsonian drug discovery from herbal medicines: what have we got from neurotoxic models?

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines are used to treat Parkinson's disease (PD) in ancient medical systems in Asian countries such as India, China, Japan and Korea based on their own anecdotal or experience-based theories.

AIM OF THE REVIEW

To systematically summarize and analyze the anti-Parkinsonian activities of herbal preparations (including active compounds, herbal extracts and formulations) investigated in the neurotoxic models of PD and provide future references for basic and clinical investigations.

MATERIALS AND METHODS

All the herbal materials tested on in vitro and in vivo neurotoxic models of PD were retrieved from PubMed database by using pre-set searching strings. The relevant compounds and herbal extracts with anti-Parkinsonian activities were included and analyzed according to their chemical classifications or biological activities.

RESULTS

A total of 51 herbal medicines were analyzed. A diversity of compounds isolated from herbal materials were reported to be effective on neurotoxic models of PD by modulating multiple key events or signaling pathways implicated in the pathogenesis of PD. The main structure types of these compounds belong to catechols, stilbenoids, flavonoids, phenylpropanoids and lignans, phenylethanoid glycosides and terpenes. Although some herbal extracts and formulations have shown positive results on PD animal models, the relative compounds accounting for the effects and the underlying mechanisms remain to be further investigated.

CONCLUSIONS

Herbal medicines can be an alternative and valuable source for anti-Parkinsonian drug discovery. Compounds classified into stilbenoids, flavonoids, catechols and terpenes may be the most promising candidates for further investigation. Some well-studies compounds such as baicalein, puerarin, resveratrol, curcumin and ginsenosides deserve further consideration in clinical trials. In-depth experimental studies are still needed to evaluate the efficacy of herbal extracts and formulations in PD models.

Ginsenoside-Rg1 Protects the Liver against Exhaustive Exercise-Induced Oxidative Stress in Rats

Despite regular exercise benefits, acute exhaustive exercise elicits oxidative damage in liver. The present study determined the hepatoprotective properties of ginsenoside-Rg1 against exhaustive exercise-induced oxidative stress in rats. Forty rats were assigned into vehicle and ginsenoside-Rg1 groups (0.1 mg/kg bodyweight). After 10-week treatment, ten rats from each group performed exhaustive swimming. Estimated oxidative damage markers, including thiobarbituric acid reactive substance (TBARS) (67%) and protein carbonyls (56%), were significantly (P < 0.01) elevated after exhaustive exercise but alleviated in ginsenoside-Rg1 pretreated rats. Furthermore, exhaustive exercise drastically decreased glutathione (GSH) content (∼79%) with concurrent decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. However, these changes were attenuated in Rg1 group. Additionally, increased xanthine oxidase (XO) activity and nitric oxide (NO) levels after exercise were also inhibited by Rg1 pretreatment. For the first time, our findings provide strong evidence that ginsenoside-Rg1 can protect the liver against exhaustive exercise-induced oxidative damage.

Neuroprotective effects of ginsenosides Rh1 and Rg2 on neuronal cells

Background

The present study investigates the effects of ginsenosides Rh₁ and Rg₂ against 6-hydroxydopamine (6-OHDA), a neurotoxin on SH-SY5Y cells and PC-12 cells. The effects of these two ginsenosides on neuronal differentiation are also examined.

Methods

LDH assay was used to measure cell viability after exposure to 6-OHDA and ginsenosides. Neuronal differentiation was evaluated by changes in cell morphology and density of neurite outgrowths. Western blotting was used to determine the ginsenosides' effects on activation of extracellular signal-regulated protein kinases (ERKs).

Results

Rh₁ and Rg₂ attenuated 6-OHDA toxicity in SH-SY5Y cells and induced neurite outgrowths in PC-12 cells. 6-OHDA-induced ERK phosphorylation was decreased by Rh₁ and Rg₂. 20(R)-form and 20(S)-form of the ginsenosides exerted similar effects in inducing neurite outgrowths in PC-12 cells.

Conclusion

The present study demonstrates neuroprotective effects of ginsenosides Rh₁ and Rg₂ on neuronal cell lines. These results suggest potential Chinese medicine treatment for neurodegenerative disorders (eg Parkinson's disease).

Protection against 1-methyl-4-phenylpyridinium ion (MPP+)-induced apoptosis by water extract of ginseng (Panax ginseng C.A. Meyer) in SH-SY5Y cells

ETHNOPHARMACOLOGICAL RELEVANCE

The present study investigates the protective effects of water extract of ginseng (Panax ginseng C.A. Meyer) against 1-methyl-4-phenylpyridinium ion (MPP(+))-induced cytotoxicity in SH-SY5Y human neuroblastoma cells and explores the underlying mechanisms. The approach may be used for screening therapeutic agents for degenerative disorders such as Parkinson's disease.

MATERIALS AND METHODS

SH-SY5Y human neuroblastoma cells were used to analyze the protective effects of water extract of ginseng (WEG) against multiple parameters such as MPP(+)-induced viability, oxidative injury, expression of Bax, Bcl-2, cytochrome c and cleaved caspase-3.

RESULTS

WEG exerted inhibitory effect on cell death, overproduction of ROS, elevated Bax/Bcl-2 ratio, release of cytochrome c and activation of caspase-3 expression in MPP(+)-treated SH-SY5Y cells.

CONCLUSIONS

WEG exhibited significant protective effects against MPP(+)-induced cytotoxicity in SH-SY5Y cells possibly through the suppression of ROS generation and the inhibition of mitochondria-dependent apoptotic pathway.

Ginsenoside Rg1 protects against hydrogen peroxide-induced cell death in PC12 cells via inhibiting NF-κB activation

Oxidative stress is a major cause in neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and cerebral ischemia. Ginsenoside Rg1, a natural product extracted from Panax ginseng C.A. Meyer, has been reported to exert notable neuroprotective activities, which partly ascribed to its antioxidative activity. However, its molecular mechanism against oxidative stress induced by exogenous hydrogen peroxide (H(2)O(2)) remained unclear. In this study, we investigated its effect on H(2)O(2)-induced cell death and explored possible signaling pathway in PC12 cells. We proved that pretreatment with Rg1 at concentrations of 0.1-10 μM remarkably reduced the cytotoxicity induced by 400 μM of H(2)O(2) in PC12 cells by MTT and Hoechst and PI double staining assay. Of note, we demonstrated the activation of NF-κB signaling pathway induced by H(2)O(2) thoroughly in PC12 cells, and Rg1 suppressed phosphorylation and nuclear translocation of NF-κB/p65, phosphorylation and degradation of inhibitor protein of κB (IκB) as well as the phosphorylation of IκB-kinase complex (IKK) by western blotting or indirect immunofluorescence assay. Besides, Rg1 also inhibited the activation of Akt and the extracellular signal-regulated kinase 1/2 (ERK1/2). Furthermore, the protection of Rg1 on H(2)O(2)-injured PC12 cells was attenuated by pretreatment with two NF-κB pathway inhibitors (JSH-23 or BOT-64). In conclusion, our results suggest that Rg1 could rescue the cell injury by H(2)O(2) via down-regulation NF-κB signaling pathway as well as Akt and ERK1/2 activation, which put new evidence on the neuroprotective mechanism of Rg1 against the oxidative stress and the regulatory role of H(2)O(2) in NF-κB pathway in PC12 cells.

Pharmacology of ginsenosides: a literature review

The therapeutic potential of ginseng has been studied extensively, and ginsenosides, the active components of ginseng, are shown to be involved in modulating multiple physiological activities. This article will review the structure, systemic transformation and bioavailability of ginsenosides before illustration on how these molecules exert their functions via interactions with steroidal receptors. The multiple biological actions make ginsenosides as important resources for developing new modalities. Yet, low bioavailability of ginsenoside is one of the major hurdles needs to be overcome to advance its use in clinical settings.