Protective effect of panaxydol and panaxynol on sodium nitroprusside-induced apoptosis in cortical neurons

Phytochemistry, pharmacological effects and mechanism of action of volatile oil from Panax ginseng C.A.Mey: a review

Panax ginseng (P. ginseng), a traditional and highly valued botanical drug, has been used for thousands of years and is known around the world for its uses in food, medicine, and healthcare. The comprehensive study of P. ginseng is crucial for the quality assurance of medicinal materials and optimal resource utilization. Despite being present in trace amounts, P. ginseng volatile oil has a wide range of chemical metabolites with important medicinal potential. The volatile oil has shown promise in defending the cardiovascular system, as well as in terms of its ability of antibacterial, anti-aging, anti-platelet coagulation, anti-inflammatory, support the nervous system nutritionally, and shield it from harm. Due to its low composition and lack of thorough investigation, P. ginseng volatile oil's therapeutic applicability is still restricted although it exhibited many benefits. This review aims to provide insights into the chemical composition, extraction processes, pharmacological effects, and mechanisms of action of P. ginseng volatile oil, and to provide theoretical support and guidelines for future research and clinical application.

Panaxynol ameliorates cardiac ischemia/reperfusion injury by suppressing NLRP3-induced pyroptosis and apoptosis via HMGB1/TLR4/NF-κB axis

BACKGROUND AND PURPOSE

Panaxynol (PNN) is a common natural minor component in Umbelliferae plants. Many clinical studies have shown that PNN exhibits nutritional value and anti-inflammatory and other pharmacological activities. However, whether PNN can mediate cardiac ischemia/reperfusion injury (IRI) remains unclear. Here, we aimed to determine the potential effects of PNN on myocardial IRI.

METHODS

Myocardial IRI was stimulated in a mouse IRI model, and neonatal rat ventricle myocytes (NRVMs) were exposed to hypoxia/reoxygenation to construct in an vitro model. Myocardial infarction size, myocardial tissue injury, myocardial apoptotic index, hemodynamic monitoring, pyroptosis-related proteins, cardiac enzyme activities and inflammatory responses were examined to assess myocardial injury.

RESULTS

It was found that PNN administration markedly reduced myocardial infarct size and apoptosis, suppressed myocardial damage and cell pyroptosis, attenuated pro-inflammatory cytokines and neutrophil infiltration via NLRP3 inhibitor. More importantly, PNN treatment remarkably decreased the expression of TLR4/NF-κB pathway-associated proteins and NLRP3-related pyroptosis proteins by HMGB1 inhibitor. PNN also enhanced cell viability, reduced cardiac enzyme activities, suppressed apoptosis and attenuated inflammation in the isolated NRVMs. Furthermore, vitro studies indicated that MCC950 (a NLRP3 inhibitor) increased the anti-inflammatory and anti-apoptotic effects of PNN on NRVMs via HMGB1/TLR4 pathway.

CONCLUSION

To sum up, our results demonstrate that PNN exhibits a cardioprotective effect by modulating heart IRI-induced apoptosis and pyroptosis via HMGB1/TLR4/NF-κB pathway, thereby inhibiting NLRP3 inflammasome stimulation.

Methylmercury induces lysosomal membrane permeabilization through JNK-activated Bax lysosomal translocation in neuronal cells

MeHg, an environmental toxicant, is highly toxic to the central nervous system. Recent studies have reported that LMP is an important way in the lysosomal damage. However, the role and molecular mechanism of LMP in MeHg-induced neurotoxicity remain unknown. To study MeHg-induced LMP, we used 10μM MeHg to treat SH-SY5Y cells and 2μM MeHg to treat rat cerebral cortical neurons. Acridine orange (AO) staining and analysis of cathepsin B (CTSB) release were used to determine LMP. We found that MeHg reduced red AO fluorescence and induced CTSB release from lysosomes to the cytoplasm in a time-dependent manner. Moreover, pretreatment with the CTSB inhibitor alleviated cytotoxicity in neuronal cells. These results indicate MeHg induces LMP and subsequent CTSB-dependent cytotoxicity in neuronal cells. Bax is a pore-forming protein, which is involved in mitochondrial outer membrane permeabilization. Intriguingly, we demonstrated that MeHg induced Bax to translocate to lysosomes by using immunofluorescence and Western blot analysis of subcellular fractions. Furthermore, downregulating Bax expression suppressed MeHg-induced LMP. Bax subcellular localization is regulated by protein interaction with the cytoplasmic 14-3-3. Our previous study demonstrated that JNK participated in neurotoxicity through regulating protein interaction. In the current study, we showed that JNK dissociated Bax-14-3-3 complex to facilitate Bax lysosomal translocation. Finally, inhibition of the JNK/Bax pathway could alleviate MeHg-induced cytotoxicity in neuronal cells. The present study implies that inhibiting lysosomal damage (LMP)-related signaling might alleviate MeHg neurotoxicity.

Synthesis and Biological Evaluation of Falcarinol-Type Analogues as Potential Calcium Channel Blockers

A series of enantiomers of falcarinol analogues (2) were synthesized using a chiral 1,1'-binaphth-2-ol (BINOL)-based catalytic system. The neuroprotective effects of falcarinol (1a) and its analogues (2) on PC12 cells injured by sodium azide (NaN₃) were investigated. The structure-function relationships and possible mechanism were studied. Pretreatment of PC12 cells with falcarinol analogues (R)-2d and (R)-2i for 1 h following addition of NaN₃ and culture in a CO₂ incubator for 24 h resulted in significant elevation of cell viability, as determined by a CCK-8 assay and Hoechst staining, with reduction of LDH release and MDA content, increase of SOD activity, and decrease of ROS stress, when compared with the activity of natural falcarinol (1a). These observations indicated that the falcarinol analogues (R)-2d and (R)-2i can protect PC12 cells against NaN₃-induced apoptosis via increasing resistance to oxidative stress. For the first time, falcarinol (1a) and its analogue (R)-2i were found to have potential L-type calcium channel-blocking activity, as recorded using a manual patch clamp technique on HEK-293 cells stably expressing hCav1.2 (α1C/β2a/α2δ1). These findings suggest that the mechanism of the L-type calcium channel-blocking activity of falcarinol (1a) and its analogue (R)-2i might be involved in neuroprotection by falcarinol-type analogues by inhibiting calcium overload in the upstream of the signaling pathway.

Protective effect of panaxydol against repeated administration of aristolochic acid on renal function and lipid peroxidation products via activating Keap1-Nrf2/ARE pathway in rat kidney

Panaxydol (PX), a polyacetylenic compound isolated from the roots of Panax notoginseng, is found to possess various biological functions. However, its protective effects against aristolochic acid (AA)-induced renal injury have not been elucidated yet. The present study was undertaken to elucidate the renoprotective effect of PX on Wistar male rats via activating Keap1-Nrf2/ARE pathway. Experimental animals were randomized into four groups, such as control group, I/R group, AA (5 mg/kg/d; ip for 10 days), and AA-induced rats treated with PX (10 and 20 mg/kg/d; po for 20 days). At the end of the experimental period, the rats were killed, and the biochemical parameters denoting renal functions were evaluated; histological analysis displaying the renal tissue architecture, real-time quantitative reverse-transcription polymerase chain reaction, and immunohistochemistry (IHC) analysis of Keap1-Nrf2/ARE genes were elucidated. The results demonstrated that the rats administered with AA displayed a significant increase in the blood urea nitrogen level with an increased urine creatinine and protein excretion. Also, the serum levels of urea, uric acid, and albumin levels were increased. Furthermore, the histological evaluation denoted the cellular degeneration with increased tissue lipid peroxidation levels. In contrast, rats administered with PX significantly prevented the tissue degeneration with improved antioxidant levels. Conversely, PX treatment increased the messenger RNA expression of Nrf2, NQO1, HO-1 with an attenuated expression of 4HNE and NOX-4 levels in IHC analysis. Thus, the results of the present study suggest that PX could suppress AA-induced renal failure by suppressing oxidative stress through the activation of Keap1-Nrf2 signaling pathway.

Panaxynol, a bioactive component of American ginseng, targets macrophages and suppresses colitis in mice

Ulcerative colitis has a significant impact on the quality of life for the patients, and can substantially increase the risk of colon cancer in patients suffering long-term. Conventional treatments provide only modest relief paired with a high risk of side effects, while complementary and alternative medicines can offer safe and effective options. Over the past decade, we have shown that both American ginseng and its hexane fraction (HAG) have anti-oxidant and anti-inflammatory properties that can suppress mouse colitis and prevent colitis-associated colon cancer. With the goal of isolating a single active compound, we further fractionated HAG, and found the most abundant molecule in this fraction was the polyacetylene, panaxynol (PA). After isolating and characterizing PA, we tested the efficacy of PA in the treatment and prevention of colitis in mice and studied the mechanism of action. We demonstrate here that PA effectively treats colitis in a Dextran Sulfate Sodium mouse model by targeting macrophages for DNA damage and apoptosis. This study provides additional mechanistic evidence that American ginseng can be used for conventional treatment of colitis and other diseases associated with macrophage dysfunction.

Anti-Fatigue Properties of Cultivated Wild Ginseng Distilled Extract and Its Active Component Panaxydol in Rats

Objectives

Cultivated wild ginseng (cWG), called SanYangSanSam, has been used clinically in patients with chronic fatigue in Korea. Little is known about effects of the ginseng distilled (volatile) components produced during evaporizaiton. Recently, we first identified one major component from cWG distilled extract, panaxydol, by using mass spectrometry. However, functional properties of cWG distilled extract and panaxydol remains elusive. Therefore, the present study evaluated the effect of cWG distilled extract or panaxydol on exercise-induced fatigue in rats.

Methods

Fatigue was induced by forced swimming and the immobility time was analyzed in male Sprague-Dawley rats. The animals received intraperitoneally either vehicle, cWG distilled extract, or panaxydol 10 min prior to beginning of the forced swimming test (FST) once daily for 5 days. After the FST on day 5, we also analyzed fatigue-related biochemical levels including blood urea nitrogen (BUN), lactate acid (LAC), and lactate dehydrogenase (LDH) in serum and levels of glycogen in liver and soleus muscle.

Results

The forced swimming time in cWG distilled extract (0.6 mL/kg)-treated group was significantly longer than that of control group on day 4 and 5. Panaxydol (0.1 and 0.25 mg/kg)-treated groups showed significantly enhanced performance in the forced swimming, compared to control. In addition, a significant decrease in serum LDH level was found in panaxydol-treated group, while there were no alternations in levels of serum BUN and LAC and glycogen in liver or soleus muscle.

Conclusion

The present study demonstrated cWG distilled extract and its active component panaxydol have a function of anti-fatigue.

Molecular mechanism of panaxydol on promoting axonal growth in PC12 cells

Nerve growth factor (NGF) promotes axonal growth in PC12 cells primarily by regulating the RTK-RAS-MEK-ERK pathway. Panaxydol, a polyacetylene isolated from Panax notoginseng, can mimic the effects of NGF. Panaxydol promotes neurite outgrowth in PC12 cells, but its molecular mechanism remains unclear. Indeed, although alkynol compounds such as panaxydol can increase intracellular cyclic adenosine 3',5'-monophosphate (cAMP) levels and the ERK inhibitor U0126 inhibits alkynol-induced axonal growth, how pathways downstream of cAMP activate ERK have not been investigated. This study observed the molecular mechanism of panaxydol-, NGF- and forskolin-induced PC12 cell axon growth using specific signaling pathway inhibitors. The results demonstrated that although the RTK inhibitor SU5416 obviously inhibited the growth-promoting effect of NGF, it could not inhibit the promoting effect of panaxydol on axonal growth of PC12 cells. The adenylate cyclase inhibitor SQ22536 and cAMP-dependent protein kinase inhibitor RpcAMPS could suppress the promoting effect of forskolin and panaxydol on axonal growth. The ERK inhibitor U0126 inhibited axonal growth induced by all three factors. However, the PKA inhibitor H89 inhibited the promoting effect of forskolin on axonal growth but could not suppress the promoting effect of panaxydol. A western blot assay was used to determine the effects of stimulating factors and inhibitors on ERK phosphorylation levels. The results revealed that NGF activates the ERK pathway through tyrosine receptors to induce axonal growth of PC12 cells. In contrast, panaxydol and forskolin increased cellular cAMP levels and were inhibited by adenylyl cyclase inhibitors. The protein kinase A inhibitor H89 completely inhibited forskolin-induced axonal outgrowth and ERK phosphorylation, but could not inhibit panaxydol-induced axonal growth and ERK phosphorylation. These results indicated that panaxydol promoted axonal growth of PC12 cells through different pathways downstream of cAMP. Considering that exchange protein directly activated by cAMP 1 (Epac1) plays an important role in mediating cAMP signaling pathways, RNA interference experiments targeting the Epac1 gene were employed. The results verified that Epac1 could mediate the axonal growth signaling pathway induced by panaxydol. These findings suggest that compared with NGF and forskolin, panaxydol elicits axonal growth through the cAMP-Epac1-Rap1-MEK-ERK-CREB pathway, which is independent of PKA.

N-stearoyltyrosine protects primary cortical neurons against oxygen-glucose deprivation-induced apoptosis through inhibiting anandamide inactivation system

N-stearoylthrosine (NST), a synthesized anandamide (AEA) analogue, plays a neuroprotective role in neurodegenerative diseases and cerebrovascular diseases. Several studies have demonstrated that the endocannabinoids systems (ECS) are involved in the neuroprotective effects against cerebral ischemic injury. Oxygen-glucose deprivation (OGD)-induced neuronal injury elevated the levels of endocannabinoids and activated ECS. This research was conducted to investigate the neuroprotective effect of NST against OGD-induced neuronal injury in cultured primary cortical neurons and the potential mechanism involved. Cortical neurons were treated with NST at indicate concentrations for 30min prior to injury and OGD injured neurons were incubated with normal conditions for 0-24h. The best neuroprotective effect of NST against OGD-induced injury occurred at 10μM. All data indicated that the neuroprotective effect of NST against OGD-induced injury resulted from blocking anandamide membrane transporter (AMT) (IC₅₀=11.74nM) and inhibiting fatty acid amide hydrolase activity (FAAH) (IC₅₀=16.54nM). Our findings demonstrated that NST has an important role in cerebral ischemic injury pathological progression through activating cannabinoid receptors by inhibiting AEA inactivation system. These data suggested a potential role for NST in the therapeutic consideration of cerebral ischemic injury. However, inhibition of AEA inactivation system may provide a neuroprotective effect during cerebral ischemic injury.

Artemisinin conferred ERK mediated neuroprotection to PC12 cells and cortical neurons exposed to sodium nitroprusside-induced oxidative insult

The production of nitric oxide (NO) is one of the primary mediators of ischemic damage, glutamate neurotoxicity and neurodegeneration and therefore inhibition of NO-induced neurotoxicity may be considered a therapeutic target for reducing neuronal cell death (neuroprotection). In this study, artemisinin, a well-known anti-malaria drug was found to suppress sodium nitroprusside (SNP, a nitric oxide donor)-induced cell death in the PC12 cells and brain primary cortical neuronal cultures. Pretreatment of PC12 cells with artemisinin significantly suppressed SNP-induced cell death by decreasing the extent of oxidation, preventing the decline of mitochondrial membrane potential, restoring abnormal changes in nuclear morphology and reducing lactate dehydrogenase release and inhibiting caspase 3/7 activities. Western blotting analysis revealed that artemisinin was able to activate extracellular regulated protein kinases (ERK) pathway. Furthermore, the ERK inhibitor PD98059 blocked the neuroprotective effect of artemisinin whereas the PI3K inhibitor LY294002 had no effect. Cumulatively these findings support the notion that artemisinin confers neuroprotection from SNP-induce neuronal cell death insult, a phenomenon coincidentally related to activation of ERK phosphorylation. This SNP-induced oxidative insult in PC12 cell culture model may be useful to investigate molecular mechanisms of NO-induced neurotoxicity and drug-induced neuroprotection, and to generate novel therapeutic concepts for ischemic disease treatment.

Bioactivity-guided isolation of polyacetylenes with inhibitory activity against NO production in LPS-activated RAW264.7 macrophages from the rhizomes of Atractylodes macrocephala

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Atractylodes macrocephala (Compositae) is one of the most well-known traditional Chinese medicine in China, Japan and Korea, which has a long history of use for the treatment of splenic asthenia, edema, anorexia, and excessive perspiration, etc. As active compounds of anti-inflammatory activity of this medicinal plant have not been fully elucidated, the aim of this study was to isolate and identify the active constituents inhibiting nitric oxide (NO) production from the rhizomes of A. macrocephala.

MATERIALS AND METHODS

Inhibitory activity against NO production in lipopolysaccharide-activated RAW264.7 macrophages was evaluated by Griess reaction. Fifteen polyacetylenes were isolated from the active ethyl acetate extract using activity-guided screening. The structures of all compounds were elucidated by spectroscopic methods and comparison with published data. The compounds were further tested for their inhibitory activity against NO production.

RESULTS

Seven new polyacetylenes, named atractylodemaynes A-G (1-7), along with eight known ones (8-15) were isolated. Compound 14 was isolated for the first time from the rhizomes of A. macrocephala. The study showed that the tested compounds exhibited inhibitory activity against NO production in a dose-dependent manner. Among them, compounds 10, 11 and 12 had relatively stronger inhibitory effect with IC50 values of 28, 23 and 19μM, respectively.

CONCLUSION

The results demonstrated that the polyacetylenes might greatly contribute to the anti-inflammatory activity of the rhizomes of A. macrocephala.

Growth inhibition and induction of differentiation by panaxydol in rat C6 glioma cells

OBJECTIVES

Panaxydol is a naturally occurring non-peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well-known Chinese traditional medicine. In this study, we aimed to investigate the effects of panaxydol on growth inhibition and its mechanisms in C6 rat glioma cells.

METHODS

The effects of panaxydol on cell proliferation, morphologic changes, glial fibrillary acidic protein (GFAP) expression and cell cycle regulation in rat C6 cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, hematoxylin and eosin (HE) staining, immunocytochemistry, flow cytometric analysis and Western blot respectively.

RESULTS

Panaxydol markedly inhibited the proliferation of C6 cells in a dose-dependent manner with IC50 of 39.5 +/- 2.3 microM. In addition, the cell morphologic changes and increased expression of GFAP in C6 cells in the presence of panaxydol implied a cellular differentiation. Flow cytometric analysis revealed that panaxydol-treated cells accumulated in G0/G1 phase with a marked decrease in the number of C6 cells at S phase. Western blot analysis demonstrated that panaxydol resulted in an increase in the protein expression of p27 in C6 cells as early as 3 hours after treatment consistent with the differentiation response, but protein expression of p53, p21, p16 and pRb remained unchanged.

CONCLUSION

These findings suggest that panaxydol inhibits the proliferation of C6 cells via G0/G1 cell cycle arrest in association with induction of p27 expression and differentiation.

Antioxidant properties of Taraxacum officinale fruit extract are involved in the protective effect against cellular death induced by sodium nitroprusside in brain of rats

CONTEXT

Taraxacum officinale Weber (Asteraceae), known as dandelion, is used for medicinal purposes due to its choleretic, diuretic, antitumor, antioxidant, antiinflammatory, and hepatoprotective properties.

OBJECTIVE

We sought to investigate the protective activity of T. officinale fruit extract against sodium nitroprusside (SNP)-induced decreased cellular viability and increased lipid peroxidation in the cortex, hippocampus, and striatum of rats in vitro. To explain the mechanism of the extract's antioxidant activity, its putative scavenger activities against NO, DPPH·, OH·, and H(2)O(2) were determined.

METHODS

Slices of cortex, hippocampus, and striatum were treated with 50 μM SNP and T. officinale fruit ethanolic extract (1-20 µg/mL) to determine cellular viability by MTT reduction assay. Lipid peroxidation was measure in cortical, hippocampal and striatal slices incubates with SNP (5 µM) and T. officinale fruit extract (1-20 µg/mL). We also determined the scavenger activities of T. officinale fruit extract against NO·, DPPH·, OH·, and H(2)O(2), as well as its iron chelating capacity.

RESULTS

The extract (1, 5, 10, and 20 μg/mL) protected against SNP-induced decreases in cellular viability and increases in lipid peroxidation in the cortex, hippocampus, and striatum of rats. The extract had scavenger activity against DPPH· and NO· at low concentrations and was able to protect against H(2)O(2) and Fe(2+)-induced deoxyribose oxidation.

CONCLUSION

T. officinale fruit extract has antioxidant activity and protects brain slices against SNP-induced cellular death. Possible mechanisms of action include its scavenger activities against reactive oxygen species (ROS) and reactive nitrogen species (RNS), which are attributed to the presence of phenolic compounds in the extract.

Subtle cytotoxicity and genotoxicity differences in superparamagnetic iron oxide nanoparticles coated with various functional groups

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely utilized for the diagnosis and therapy of specific diseases, as magnetic resonance imaging (MRI) contrast agents and drug-delivery carriers, due to their easy transportation to targeted areas by an external magnetic field. For such biomedical applications, SPIONs must have multifunctional characteristics, including optimized size and modified surface. However, the biofunctionality and biocompatibility of SPIONs with various surface functional groups of different sizes have yet to be elucidated clearly. Therefore, it is important to carefully monitor the cytotoxicity and genotoxicity of SPIONs that are surfaced-modified with various functional groups of different sizes. In this study, we evaluated SPIONs with diameters of approximately 10 nm and 100~150 nm, containing different surface functional groups. SPIONs were covered with −O⁻ groups, so-called bare SPIONs. Following this, they were modified with three different functional groups – hydroxyl (−OH), carboxylic (−COOH), and amine (−NH₂) groups – by coating their surfaces with tetraethyl orthosilicate (TEOS), (3-aminopropyl)trimethoxysilane (APTMS), TEOS-APTMS, or citrate, which imparted different surface charges and sizes to the particles. The effects of SPIONs coated with these functional groups on mitochondrial activity, intracellular accumulation of reactive oxygen species, membrane integrity, and DNA stability in L-929 fibroblasts were determined by water-soluble tetrazolium, 2′,7′-dichlorodihydrofluorescein, lactate dehydrogenase, and comet assays, respectively. Our toxicological observations suggest that the functional groups and sizes of SPIONs are critical determinants of cellular responses, degrees of cytotoxicity and genotoxicity, and potential mechanisms of toxicity. Nanoparticles with various surface modifications and of different sizes induced slight, but possibly meaningful, changes in cell cytotoxicity and genotoxicity, which would be significantly valuable in further studies of bioconjugation and cell interaction for drug delivery, cell culture, and cancer-targeting applications.

Ginseng for cognition

BACKGROUND

Ginseng is a herbal medicine in widespread use throughout the world. Its effect on the brain and nervous system has been investigated. It has been suggested, on the basis of both laboratory and clinical studies, that it may have beneficial effects on cognitive performance.

OBJECTIVES

To evaluate the efficacy and adverse effects of ginseng given to improve cognitive performance in healthy participants, participants with cognitive impairment or dementia.To highlight the quality and quantity of research evidence available.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS, clinical trials registries and grey literature sources were searched on 24 February 2009 using the following terms: ginseng* OR panax OR ginsan OR "Jen Shen"OR shinseng OR Renshen OR schinseng OR ninjin OR gingilone OR panaxoside* OR ginsenoside* OR protopanaxa* OR protopanaxadiol OR protopanaxatriol OR panaxagin OR ginsenol OR ginsenine and terms for dementia and cognition. The CDCIG Specialized Register contains records from all major health care databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many clinical trials registries and grey literature sources.

SELECTION CRITERIA

All double-blind and single-blind randomized, placebo controlled trials assessing the effects of ginseng on cognitive function were eligible for inclusion. Interventions were considered to be ginseng if they were compounds containing ginseng or active agents of the Panax genus as the major component.

DATA COLLECTION AND ANALYSIS

Characteristics of each included trial were extracted independently by two reviewers using a self-developed data extraction form and entered into RevMan 5.0 software. Authors of identified trials were contacted for additional information and unpublished data. The effects of ginseng in healthy participants, participants with cognitive impairment or dementia were addressed independently.

MAIN RESULTS

Nine randomized, double-blind, placebo controlled trials meeting the inclusion criteria were identified. Eight trials enrolled healthy participants, and one was of subjects with age-associated memory impairment (AAMI).Only five of the identified trials had extractable information and were included in the analysis. Four studies investigated the effects of ginseng extract and one assessed the efficacy of ginseng compound HT008-1. All of these trials investigated the effects of ginseng on healthy participants. Pooling the data was impossible owing to heterogeneity in outcome measures, trial duration, and ginseng dosage. Results of the analysis suggested improvement of some aspects of cognitive function, behavior and quality of life. No serious adverse events associated with ginseng were found.

AUTHORS' CONCLUSIONS

Currently, there is a lack of convincing evidence to show a cognitive enhancing effect of Panax ginseng in healthy participants and no high quality evidence about its efficacy in patients with dementia. Randomized, double-blind, placebo-controlled, parallel group trials with large sample sizes are needed to further investigate the effect of ginseng on cognition in different populations, including dementia patients.

Anti-alpha-internexin autoantibody from neuropsychiatric lupus induce cognitive damage via inhibiting axonal elongation and promote neuron apoptosis

BACKGROUND

Neuropsychiatric systemic lupus erythematosus (NPSLE) is a major complication for lupus patients, which often leads to cognitive disturbances and memory loss and contributes to a significant patient morbidity and mortality. The presence of anti-neuronal autoantibodies (aAbs) has been identified; as examples, anti-NMDA receptors and anti-Ribsomal P aAbs have been linked to certain pathophysiological features of NPSLE.

METHODS AND FINDINGS

In the current study, we used a proteomic approach to identify an intermediate neurofilament alpha-internexin (INA) as a pathogenetically relevant autoantigen in NPSLE. The significance of this finding was then validated in an expanded of a cohort of NPSLE patients (n = 67) and controls (n = 270) by demonstrating that high titers of anti-INA aAb was found in both the serum and cerebrospinal fluid (CSF) of approximately 50% NPSLE. Subsequently, a murine model was developed by INA immunization that resulted in pronounced cognitive dysfunction that mimicked features of NPSLE. Histopathology in affected animals displayed cortical and hippocampal neuron apoptosis. In vitro studies further demonstrated that anti-INA Ab mediated neuronal damage via inhibiting axonal elongation and eventually driving the cells to apoptosis.

CONCLUSIONS

Taken together, this study identified a novel anti-neurofilament aAb in NPSLE, and established a hitherto undescribed mechanism of aAb-mediated neuron damage that could have relevance to the pathophysiology of NPSLE.

EGb761 protects hydrogen peroxide-induced death of spinal cord neurons through inhibition of intracellular ROS production and modulation of apoptotic regulating genes

The present study was conducted to investigate whether Ginkgo biloba extract (EGb) 761 could protect spinal cord neurons from H(2)O(2)-induced toxicity. In primary spinal cord neurons isolated from embryonic day 14 rats, H(2)O(2) administration resulted in a significant decrease in the survival of spinal cord neurons. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and Hoechst 33342 nuclear staining showed that these cells die by apoptosis. Such neuronal death, however, was significantly reversed by EGb761 in a dose-dependent manner. Moreover, a marked increase in intracellular free radical generation was found after the H(2)O(2) administration which could be reversed almost completely by EGb761, indicating that inhibition of free radical generation is an important mechanism of the anti-apoptosis action of EGb761. Finally, treatment of cells with H(2)O(2) for 12 h reduced the expression of Bcl-2, an anti-apoptotic gene, by 70% but showed no effect on the level of Bax, a pro-apoptotic gene. EGb76 treatment, however, significantly reversed H(2)O(2)-induced reduction of Bcl-2 expression and inhibited Bax expression by 2.3-fold. Thus, our study provided evidence showing that the protective effect of EGb761 on spinal cord neuronal apoptosis after oxidative stress is mediated, at least in part, by its anti-oxidative action and regulation of apoptosis-related genes Bcl-2 and Bax.

Effect of panaxydol on hypoxia-induced cell death and expression and secretion of neurotrophic factors (NTFs) in hypoxic primary cultured Schwann cells

It has been shown that panaxydol (PND) can mimic the neurotrophic effect of nerve growth factor (NGF) normally secreted by Schwann cells (SC) and protect neurons against injury. To evaluate the effect of PND on hypoxia-induced SC death and expression and secretion of neurotrophic factors (NGF and brain derived neurotrophic factor (BDNF)), hypoxic SCs were cultured in vitro and then treated with PND (0-20 microM). The MTT (3(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide) assay, immunocytochemistry, ELISA and RT-PCR were employed to examine the effects. We found that hypoxia resulted in a significant decrease in SCs viability (MTT: 64+/-4.7% of control group) and nearly a 3.3-fold increase of intracellular level of active caspase-3. PND (5-20 microM) treatment significantly rescued the SCs from hypoxia-induced injury (85+/-8.2%; 92+/-8.6%; 87+/-7.3%) and reduced caspase-3 activity with the maximal effect occurred at 10 microM (P<0.01), reducing to about 1.6-fold of control level. Furthermore, PND treatment also enhanced NGF and BDNF mRNA levels in hypoxic SCs and promoted protein expression and secretion. BDNF mRNA in hypoxic SCs was restored to about 90% of normal level and NGF mRNA was elevated to 1.4-fold of control after 10 microM PND treatment. These observations showed that PND protects primary cultured SCs against hypoxia-induced injury and enhances NTF-associated activities.