Neuroprotective effects of Polygonum multiflorum extract against glutamate-induced oxidative toxicity in HT22 hippocampal cells

Preclinical Evidence and Underlying Mechanisms of Polygonum multiflorum and Its Chemical Constituents Against Cognitive Impairments and Alzheimer's Disease

Objectives

Cognitive impairments, ranging from mild to severe, adversely affect daily functioning, quality of life, and work capacity. Despite significant efforts in the past decade, more than 200 promising drug candidates have failed in clinical trials. Herbal remedies are gaining interest as potential treatments for dementia due to their long history and safety, making them valuable for drug development. This review aimed to examine the mechanisms behind the effect of Polygonum multiflorum on cognitive function.

Methods

This study focused primarily on the effects of Polygonum multiflorum and its chemical constituents on cognitive behavioral outcomes including the Morris water maze, the passive avoidance test, and the Y maze, as well as pathogenic targets of cognitive impairment and Alzheimer's disease (AD) like amyloid deposition, amyloid precursor protein, tau hyperphosphorylation, and cognitive decline. Additionally, a thorough evaluation of the mechanisms behind Polygonum multiflorum's impact on cognitive function was conducted. We reviewed the most recent data from preclinical research done on experimental models, particularly looking at Polygonum multiflorum's effects on cognitive decline and AD.

Results

According to recent research, Poligonum multiflorum and its bioactive components, stilbene, and emodin, influence cognitive behavioral results and regulate the pathological target of cognitive impairment and AD. Their mechanisms of action include reducing oxidative and mitochondrial damage, regulating neuroinflammation, halting apoptosis, and promoting increased neurogenesis and synaptogenesis.

Conclusion

This review serves as a comprehensive compilation of current experiments on AD and other cognitive impairment models related to the therapeutic effects of Polygonum multiflorum. We believe that these findings can serve as a basis for future clinical trials and have potential applications in the treatment of human neurological disorders.

Calcium Modulating Effect of Polycyclic Cages: A Suitable Therapeutic Approach Against Excitotoxic-induced Neurodegeneration

Neurodegenerative disorders pose a significant challenge to global healthcare systems due to their progressive nature and the resulting loss of neuronal cells and functions. Excitotoxicity, characterized by calcium overload, plays a critical role in the pathophysiology of these disorders. In this review article, we explore the involvement of calcium dysregulation in neurodegeneration and neurodegenerative disorders. A promising therapeutic strategy to counter calcium dysregulation involves the use of calcium modulators, particularly polycyclic cage compounds. These compounds, structurally related to amantadine and memantine, exhibit neuroprotective properties by attenuating calcium influx into neuronal cells. Notably, the pentacycloundecylamine NGP1-01, a cage-like structure, has shown efficacy in inhibiting both N-methyl-D-aspartate (NMDA) receptors and voltage- gated calcium channels (VGCCs), making it a potential candidate for neuroprotection against excitotoxic-induced neurodegenerative disorders. The structure-activity relationship of polycyclic cage compounds is discussed in detail, highlighting their calcium-inhibitory activities. Various closed, open, and rearranged cage compounds have demonstrated inhibitory effects on calcium influx through NMDA receptors and VGCCs. Additionally, these compounds have exhibited neuroprotective properties, including free radical scavenging, attenuation of neurotoxicities, and reduction of neuroinflammation. Although the calcium modulatory activities of polycyclic cage compounds have been extensively studied, apart from amantadine and memantine, none have undergone clinical trials. Further in vitro and in vivo studies and subsequent clinical trials are required to establish the efficacy and safety of these compounds. The development of polycyclic cages as potential multifunctional agents for treating complex neurodegenerative diseases holds great promise.

Combination of Polygoni Multiflori Radix Praeparata and Acori Tatarinowii Rhizoma Alleviates Learning and Memory Impairment in Scopolamine-Treated Mice by Regulating Synaptic-Related Proteins

Polygoni Multiflori Radix Praeparata (ZhiHeShouWu, PMRP) and Acori Tatarinowii Rhizoma (ShiChangPu, ATR) and their traditional combination (PA) are frequently used in traditional Chinese medicine to prevent and treat Alzheimer disease (AD) based on the theory that PMRP tonifies the kidney and ATR dissipates phlegm. However, the components of PA and their mechanisms of action are not known. The present study analyzed the active components of PA, and investigated the protective effect of PA against cognitive impairment induced by scopolamine in mice along with the underlying mechanism.The aqueous extract of PA was analyzed by high-performance liquid chromatography–mass spectrometry (HPLC-MS) and gas chromatography (GC)-MS in order to identify the major components. To evaluate the protective effect of PA against cognitive dysfunction, mice were orally administered PA, PMRP, or ATR for 30 days before treatment with scopolamine. Learning and memory were assessed in mice with the Morris water maze test; neurotransmitter levels in the hippocampus were analyzed by HPLC-MS; and the expression of synapse-related proteins in the hippocampus was detected by western blotting and immunohistochemistry. Eight active compounds in PA and rat plasma were identified by HPLC-MS and GC-MS. Plasma concentrations of 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside, emodin, α-asarone, and asarylaldehyde were increased following PA administration; meanwhile, gallic acid, emodin-8-O-β-d-glucopyranoside, β-asarone, and cis-methyl isoeugenol concentrations were similar in rats treated with PA, PMRP, and ATR. In scopolamine-treated mice, PA increased the concentrations of neurotransmitters in the hippocampus, activated the brain-derived neurotrophic factor (BDNF)/extracellular signal-regulated kinase (ERK)/cAMP response element binding protein (CREB) signaling pathway, and increased the expression of p90 ribosomal S6 kinase (p90RSK) and postsynaptic density (PSD)95 proteins. Thus, PA alleviates cognitive deficits by enhancing synaptic-related proteins, suggesting that it has therapeutic potential for the treatment of aging-related diseases such as AD.

Metabolomics Approach for Discrimination and Quality Control of Natural and Commercial Fallopia multiflora Products in Vietnam

A precise HPLC-DAD-based quantification together with the metabolomics statistical method was developed to distinguish and control the quality of Fallopia multiflora, a popular medicinal material in Vietnam. Multivariate statistical methods such as hierarchical clustering analysis and principal component analysis were utilized to compare and discriminate six natural and twelve commercial samples. 2,3,4′,5-Tetrahydroxystilbene 2-O-β-D-glucopyranoside (THSG) (1), emodin (4), and the new compound 6-hydroxymusizin 8-O-α-D-apiofuranosyl-(1⟶6)-β-D-glucopyranoside (5) could be considered as important markers for classification of F. multiflora. Furthermore, seven phenolics were quantified that the variation in the contents of selected metabolites revealed the differences in the quality of natural and commercial samples. Recovery of the compounds from the analytes was more than 98%, while the limits of detection (LOD) and the limits of quantitation (LOQ) ranged from 0.5 to 6.6 μg/ml and 1.5 to 19.8 μg/ml, respectively. The linearity, LOD, LOQ, precision, and accuracy satisfied the criteria FDA guidance on bioanalytical methods. Overall, this method is a promising tool for discrimination and quality assurance of F. multiflora products.

Potential protective roles of phytochemicals on glutamate-induced neurotoxicity: A review

Glutamate, as an essential neurotransmitter, has been thought to have different roles in the central nervous system (CNS), including nerve regeneration, synaptogenesis, and neurogenesis. Excessive glutamate causes an up-regulation of the multiple signaling pathways, including phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Akt/mammalian target of rapamycin (mTOR) protein, mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK)1/2, and autophagy that are involved in neurodegenerative diseases pathophysiology. There are numerous findings on curcumin, astaxanthin, thymoquinone, and berberine, as natural products, which have outstanding effects in cell signaling far beyond their anti-oxidant activity, considering as a potential therapeutic target for glutamate excitotoxicity. Herein, we address the role of glutamate as a potential target in neurodegenerative diseases and discuss the protective effects of certain phytochemicals on glutamate-induced neurotoxicity.

Polygonum multiflorum Thunb. Extract Stimulates Melanogenesis by Induction of COX2 Expression through the Activation of p38 MAPK in B16F10 Mouse Melanoma Cells

Polygonum multiflorum Thunb. (PM) root extracts have been used for treating graying hair in Oriental medicine; however, the molecular mechanisms underlying the melanogenic effects of PM root have not been fully understood. In the present study, we investigated the melanogenic effects of an ethanolic extract of PM root (PME) and the mechanisms involved. We examined the effects of PME on cell viability, cellular melanin content, and tyrosinase activity in B16F10 cells. The melanogenic mechanism of PME was explored using signaling inhibitors and examining the expression of melanogenic genes and signaling molecules by western blot and RT-qPCR analyses. PME did not exhibit any cytotoxicity in B16F10 cells compared to that in control cells. PME treatment significantly increased melanin production and tyrosinase activity. In addition, PME induced the expression of cyclooxygenase-2 (COX2) as well as that of melanogenic genes, such as microphthalmia-associated transcription factor (MiTF), tyrosinase-related protein (Trp) 1, Trp2, and tyrosinase, in B16F10 cells. PME treatment increased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK), and pretreatment with SB 203580, a p38 MAPK inhibitor, significantly suppressed this PME-induced increase in the expression of COX2 and melanogenic genes. These results indicate that PME induced the expression of melanogenic genes by inducing COX2 expression via the activation of the p38 MAPK pathway, thereby contributing to the enhancement of melanogenesis.

A Candidate Drug for Nonalcoholic Fatty Liver Disease: A Review of Pharmacological Activities of Polygoni Multiflori Radix

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients' compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

Neuroprotective effects of Dendropanax morbifera leaves on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells

ETHNOPHARMACOLOGICAL RELEVANCE

Dendropanax morbifera (DM) has long been used as a traditional herbal medicine for migraines. Glutamate toxicity and oxidative stress have emerged as the possible triggers implicated in migraine pathogenesis.

AIM OF THE STUDY

We aimed to examine the neuroprotective effects of DM leaves (DML) on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells.

MATERIALS AND METHODS

Molecular authentication of DML was assessed using DNA barcoding analysis. Four different solvent extracts of DML were prepared and subjected to antioxidant activity and phytochemical assays. Neuroprotective effects of DML extracts were evaluated using relevant biochemical and imaging assays that measure cell viability/death, ROS generation, Ca²⁺ levels, mitochondrial dysfunction, and AIF nuclear translocation.

RESULTS

The sequences of matK, rbcL, atpF-H, and psbK-I in DML were identical with those in voucher specimens, confirming that DML was indeed D. morbifera. The ethyl acetate extract of DML (DMLE) showed the highest flavonoid and phenolic content, and prominent DPPH/superoxide radical scavenging and reducing power activities. In the HT22 cell model, glutamate was shown to be the causative agent for apoptotic cell death via elevation of intracellular ROS and Ca²⁺ levels, induction of mitochondrial depolarization and membrane permeabilization, and translocation of AIF to the nucleus. Of note, N-acetyl-L-cysteine and necrostatin-1, but not z-VAD-fmk, completely prevented glutamate-induced cell death, implying that oxidative stress and AIF translocation were pivotal in glutamate cytotoxicity. DMLE significantly recovered glutamate-induced apoptotic cell death in a concentration-dependent manner. It completely inhibited intracellular/mitochondrial ROS generation, the elevation of Ca²⁺ levels, and mitochondrial dysfunction induced by glutamate during early exposure within 8 h. It significantly reversed subsequent AIF nuclear translocation after 12 h of treatment. Antioxidant activities of DMLE may be the protective mechanism that regulates homeostatic balance of ROS and Ca²⁺ as well as maintains mitochondrial function.

CONCLUSIONS

DMLE shows significant neuroprotective effects against glutamate-induced oxidative neuronal cell death. Therefore, DM could be a potential therapeutic candidate for neurological disorders propagated by glutamate toxicity.

Metabolomics profiling of Polygoni Multiflori Radix and Polygoni Multiflori Radix Preparata extracts using UPLC-Q/TOF-MS

Background

The side effects caused by Polygoni Multiflori Radix (PMR) and Polygoni Multiflori Radix Praeparata (PMRP) have often appeared globally. There is no research on the changes of endogenous metabolites among PMR- and PMRP-treated rats. The aim of this study was to evaluate the varying metabolomic effects between PMR- and PMRP-treated rats. We tried to discover relevant differences in biomarkers and endogenous metabolic pathways.

Methods

Hematoxylin and eosin staining and immunohistochemistry staining were performed to find pathological changes. Biochemical indicators were also measured, one-way analysis of variance with Dunnett’s multiple comparison test was used for biochemical indicators comparison among various groups. Metabolomics analysis based on ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q/TOF-MS) was performed to find the changes in metabolic biomarkers. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to reveal group clustering trend, evaluate and maximize the discrimination between the two groups. MetaboAnalyst 4.0 was performed to find and confirm the pathways.

Results

PMR extracts exhibited slight hepatotoxic effects on the liver by increasing aspartate and alanine aminotransferase levels. Twenty-nine metabolites were identified as biomarkers, belonging to five pathways, including alpha-linolenic acid metabolism, taurine and hypotaurine metabolism, glycerophospholipid metabolism, arginine and proline metabolism, and primary bile acid biosynthesis.

Conclusion

This study provided a comprehensive description of metabolomic changes between PMR- and PMRP-treated rats. The underlying mechanisms require further research.

Neuroprotective effect of polysaccharide separated from Perilla frutescens Britton var. acuta Kudo against H2O2-induced oxidative stress in HT22 hippocampus cells

This study was carried out to evaluate the neuroprotective activity of polysaccharide extracts isolated from Perilla frutescens (PEPF) in H₂O₂-treated HT22 hippocampus cells. The PEPF treatment was found to increase the anti-oxidant activities of HT22 hippocampus cells. PEPF treatment resulted in a significant protection of HT22 hippocampus cells against H₂O₂-induced neurotoxicity, this protection ultimately occurred through an inhibition of ROS-mediated intracellular Ca²⁺ levels leading to MAPKs and NF-κB, as well as the accumulation of PI3K/AKT and Nrf2-mediated HO-1/NQO1 pathways. Furthermore, PEPF not only decreased the expression of Bax, cytochrome c, and cleaved caspases-3, -8, and -9, but also increased the expression of PARP and Bcl-2 in the H₂O₂-treated HT22 hippocampus cells, which overall contributed to the neuroprotective action. PEPF retains its mitochondrial membrane potential and reduces the elevated levels of sub-G1 phase and apoptotic morphological features induced by H₂O₂. It also reduces the malondialdehyde levels and enhances the intracellular SOD activity.

Neuroprotective Effects of Sigesbeckia pubescens Extract on Glutamate-Induced Oxidative Stress in HT22 Cells via Downregulation of MAPK/caspase-3 Pathways

Sigesbeckia pubescens (SP) is a traditional Chinese medicine, possessing antioxidant and anti-inflammatory activities. In this study, we evaluate the neuroprotective activities of SP extract on glutamate-induced oxidative stress in HT22 cells and the molecular mechanism underlying neuroprotection. We applied 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), crystal violet, reactive oxygen species (ROS), lactate dehydrogenase (LDH), quantitative real-time polymerase chain reaction (qPCR), and western blot analyses for assessing the neuroprotective effects of SP extract. The experimental study revealed that SP considerably increased the cell viability, and reduced the oxidative stress promoted ROS and LDH generation in HT22 cells in a dose-dependent manner. Additionally, the morphology of HT22 cells was effectively improved by SP. Upregulated gene expressions of mitogen-activated protein kinase (MAPK) were markedly attenuated by SP. Similarly, SP notably suppressed the ROS-mediated phosphorylation of MAPK (pERK1/2, pJNK, and pp38) cascades and activation of apoptotic factor caspase-3 signaling pathway that overall contributed to the neuroprotection. Taken together, SP may exert neuroprotective effects via alteration of MAPK and caspase-3 pathways under oxidative stress condition. Therefore, SP is a potential agent for preventing oxidative stress-mediated neuronal cell death.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Polygonum multiflorum Decreases Airway Allergic Symptoms in a Murine Model of Asthma

The root of Polygonum multiflorum (also called He-Shou-Wu in Chinese) is a common herb and medicinal food in Asia used for its anti-aging properties. Our study investigated the therapeutic potential of an extract of the root of Polygonum multiflorum (PME) in allergic asthma by using a mouse model. Feeding of 0.5 and 1 mg/mouse PME inhibited ovalbumin (OVA)-induced allergic asthma symptoms, including airway inflammation, mucus production, and airway hyper-responsiveness (AHR), in a dose-dependent manner. To discern PME's mechanism of action, we examined the profile and cytokine production of inflammatory cells in bronchial alveolar lavage fluid (BALF). We found that eosinophils, the main inflammatory cell infiltrate in the lung of OVA-immunized mice, significantly decreased after PME treatment. Th2 cytokine levels, including interleukin (IL)-4, IL-5, IL-13, eotaxin, and the proinflammatory cytokine tumor necrosis factor (TNF)-[Formula: see text], decreased in PME-treated mice. Elevated mRNA expression of Th2 transcription factor GATA-3 in the lung tissue was also inhibited after oral feeding of PME in OVA-immunized mice. Thus, we conclude that PME produces anti-asthma activity through the inhibition of Th2 cell activation.

Beneficial Effects of Polygonum multiflorum on Hippocampal Neuronal Cells and Mouse Focal Cerebral Ischemia

Beneficial effects of the water extract of Polygonum multiflorum (WEPM) and their mechanisms were investigated in HT22 hippocampal cells and hippocampus of middle cerebral artery occlusion (MCAO) mice. In HT22 cells against glutamate-induced oxidative stress, pretreatment with WEPM resulted in significantly reduced apoptotic neuronal death. Pretreatment with WEPM resulted in the suppression of ROS accumulation in connection with cellular Ca 2+ level after exposure to glutamate. Treatment with glutamate alone led to suppressed protein level of mature brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element binding protein (CREB); however, pretreatment with either WEPM or anti-oxidant N-acetyl-ʟ-cysteine (NAC) resulted in the significant enhancement of levels of these proteins. In addition, levels of mature BDNF expression and CREB phosphorylation were increased by combined treatment with WEPM, NAC, and intracellular Ca 2+ inhibitor BAPTA compared to other treatment groups. In MCAO mice, we confirmed the critical role of mature BDNF expression and CREB phosphorylation by WEPM in the neurons of the hippocampus. Our results suggest that WEPM mainly exerted beneficial effects on hippocampal neurons through the suppression of ROS accumulation and up-regulation of mature BDNF expression and CREB phosphorylation.

Neuroprotection and spatial memory enhancement of four herbal mixture extract in HT22 hippocampal cells and a mouse model of focal cerebral ischemia

BACKGROUND

Four traditional Korean medicinal herbs which act in retarding the aging process, Polygonum multiflorum Thunb., Rehmannia glutinosa (Gaertn) Libosch., Polygala tenuifolia Willd., and Acorus gramineus Soland., were prepared by systematic investigation of Dongeuibogam (Treasured Mirror of Eastern Medicine), published in the early 17th century in Korea. This study was performed to evaluate beneficial effects of four herbal mixture extract (PMC-12) on hippocampal neuron and spatial memory.

METHODS

High performance liquid chromatography (HPLC) analysis was performed for standardization of PMC-12. Cell viability, lactate dehydrogenase, flow cytometry, reactive oxygen species (ROS), and Western blot assays were performed in HT22 hippocampal cells and immunohistochemistry and behavioral tests were performed in a mouse model of focal cerebral ischemia in order to observe alterations of hippocampal cell survival and subsequent memory function.

RESULTS

In the HPLC analysis, PMC-12 was standardized to contain 3.09% 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside, 0.35% 3',6-disinapoyl sucrose, and 0.79% catalpol. In HT22 cells, pretreatment with PMC-12 resulted in significantly reduced glutamate-induced apoptotic cell death. Pretreatment with PMC-12 also resulted in suppression of ROS accumulation in connection with cellular Ca(2+) level after exposure to glutamate. Expression levels of phosphorylated p38 mitogen-activated protein kinases (MAPK) and dephosphorylated phosphatidylinositol-3 kinase (PI3K) by glutamate exposure were recovered by pretreatment with either PMC-12 or anti-oxidant N-acetyl-L-cysteine (NAC). Expression levels of mature brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element binding protein (CREB) were significantly enhanced by treatment with either PMC-12 or NAC. Combination treatment with PMC-12, NAC, and intracellular Ca(2+) inhibitor BAPTA showed similar expression levels. In a mouse model of focal cerebral ischemia, we observed higher expression of mature BDNF and phosphorylation of CREB in the hippocampus and further confirmed improved spatial memory by treatment with PMC-12.

CONCLUSIONS

Our results suggest that PMC-12 mainly exerted protective effects on hippocampal neurons through suppression of Ca(2+)-related ROS accumulation and regulation of signaling pathways of p38 MAPK and PI3K associated with mature BDNF expression and CREB phosphorylation and subsequently enhanced spatial memory.

TSG (2,3,5,4'-Tetrahydroxystilbene-2-O- β -D-glucoside) from the Chinese Herb Polygonum multiflorum Increases Life Span and Stress Resistance of Caenorhabditis elegans

2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG) was isolated from Polygonum multiflorum, a plant which is traditionally used as an anti-ageing drug. We have analysed ageing-related effects of TSG in the model organism C. elegans in comparison to resveratrol. TSG exerted a high antioxidative capacity both in a cell-free assay and in the nematode. The antioxidative capacity was even higher compared to resveratrol. Presumably due to its antioxidative effects, treatment with TSG decreased the juglone-mediated induction of the antioxidative enzyme SOD-3; the induction of the GST-4 by juglone was diminished slightly. TSG increased the resistance of C. elegans against lethal thermal stress more prominently than resveratrol (50 μM TSG increased mean survival by 22.2%). The level of the ageing pigment lipofuscin was decreased after incubation with the compound. TSG prolongs the mean, median, and maximum adult life span of C. elegans by 23.5%, 29.4%, and 7.2%, respectively, comparable to the effects of resveratrol. TSG-mediated extension of life span was not abolished in a DAF-16 loss-of-function mutant strain showing that this ageing-related transcription factor is not involved in the effects of TSG. Our data show that TSG possesses a potent antioxidative capacity, enhances the stress resistance, and increases the life span of the nematode C. elegans.

Establishment of a comprehensive list of candidate antiaging medicinal herb used in korean medicine by text mining of the classical korean medical literature, "dongeuibogam," and preliminary evaluation of the antiaging effects of these herbs

The major objectives of this study were to provide a list of candidate antiaging medicinal herbs that have been widely utilized in Korean medicine and to organize preliminary data for the benefit of experimental and clinical researchers to develop new drug therapies by analyzing previous studies. "Dongeuibogam," a representative source of the Korean medicine literature, was selected to investigate candidate antiaging medicinal herbs and to identify appropriate terms that describe the specific antiaging effects that these herbs are predicted to elicit. In addition, we aimed to review previous studies that referenced the selected candidate antiaging medicinal herbs. From our chosen source, "Dongeuibogam," we were able to screen 102 terms describing antiaging effects, which were further classified into 11 subtypes. Ninety-seven candidate antiaging medicinal herbs were selected using the criterion that their antiaging effects were described using the same terms as those employed in "Dongeuibogam." These candidates were classified into 11 subtypes. Of the 97 candidate antiaging medicinal herbs selected, 47 are widely used by Korean medical doctors in Korea and were selected for further analysis of their antiaging effects. Overall, we found an average of 7.7 previous studies per candidate herb that described their antiaging effects.

Traditional usages, botany, phytochemistry, pharmacology and toxicology of Polygonum multiflorum Thunb.: a review

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum multiflorum Thunb., which is known as Heshouwu ( in Chinese) in China. It is traditionally valued and reported for hair-blacking, liver and kidney-tonifying and anti-aging effects as well as low toxicity. The aim of this review is to provide comprehensive information on the botany, traditional uses, phytochemistry, pharmacological research and toxicology of Polygonum multiflorum, based on the scientific literature. Moreover, trends and perspectives for future investigation of this plant are discussed. It will build up a new foundation for further study on Polygonum multiflorum.

MATERIALS AND METHODS

A systematic review of the literature on Polygonum multiflorum was performed using several resources, including classic books on Chinese herbal medicine and various scientific databases, such as PubMed, SciFinder, the Web of Science, Science Direct, China Knowledge Resource Integrated (CNKI).

RESULTS

Polygonum multiflorum is widely distributed throughout the world and has been used as a traditional medicine for centuries in China. The ethnomedical uses of Polygonum multiflorum have been recorded in many provinces of China and Japan for nine species of adulterants in six families. More than 100 chemical compounds have been isolated from this plant, and the major components have been determined to be stilbenes, quinones, flavonoids and others. Crude extracts and pure compounds of this plant are used as effective agents in pre-clinical and clinical practice due to their anti-aging, anti-hyperlipidaemia, anti-cancer and anti-inflammatory effects and to promote immunomodulation, neuroprotection, and the curing of other diseases. However, these extracts can also lead to hepatotoxicity, nephrotoxicity and embryonic toxicity. Pharmacokinetic studies have demonstrated that the main components of Polygonum multiflorum, such as 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucopyranoside and emodin are distributed among many organs and tissues.

CONCLUSION

Therapeutic potential of Polygonum multiflorum has been demonstrated in the conditions like Alzheimer׳s disease, Parkinson׳s disease, hyperlipidaemia, inflammation and cancer, which is attributed to the presence of various stilbenes, quinones, flavonoids, phospholipids and other compounds in the drug. On the other hand, the adverse effects (hepatotoxicity, nephrotoxicity, and embryonic toxicity) of this plant were caused by the quinones, such as emodin and rhein. Thus more pharmacological and toxicological mechanisms on main active compounds are necessary to be explored, especially the combined anthraquinones (Emodin-8-O-β-d-glucopyranoside, Physcion-8-O-β-d-glucopyranoside, etc.) and the variety of stilbenes.

Liver Damage Associated with Polygonum multiflorum Thunb.: A Systematic Review of Case Reports and Case Series

Objective. To summarize the characteristics and analysis of relevant factors and to give references for prevention and further study of liver damage associated with Polygonum multiflorum Thunb. (HSW), we provide a systematic review of case reports and case series about liver damage associated with HSW. Methods. An extensive search of 6 medical databases was performed up to June 2014. Case reports and case series involving liver damage associated with HSW were included. Results. This review covers a total of 450 cases in 76 articles. HSW types included raw and processed HSW decoction pieces and many Chinese patent medicines that contain HSW. Symptoms of liver damage occur mostly a month or so after taking the medicine, mainly including jaundice, fatigue, anorexia, and yellow or tawny urine. Of the 450 patients, two cases who received liver transplantation and seven who died, the remaining 441 cases recovered or had liver function improvement after discontinuing HSW products and conservative care. Conclusion. HSW causes liver toxicity and may cause liver damage in different degrees and even lead to death; most of them are much related to long-term and overdose of drugs. Liver damage associated with HSW is reversible, and, after active treatment, the majority can be cured. People should be alert to liver damage when taking HSW preparations.

Emodin induces neurite outgrowth through PI3K/Akt/GSK-3β-mediated signaling pathways in Neuro2a cells

In this study, a neurite outgrowth-inducing substance was isolated from the ethylacetate extract of the Polygonum multiflorum roots and identified as emodin by gas-liquid chromatography-mass spectrometry and (1)H NMR and (13)C NMR. Emodin displayed remarkable neurite outgrowth-inducing activity in Neuro2a cells, as demonstrated by morphological changes and immunocytochemistry for class III β-tubulin. Emodin exhibited a stronger neutrophic activity than retinoic acid (RA) known as inducer of neurite outgrowth in Neuro2a cells. Emodin treatment resulted in marked increases in phosphorylation of Akt a direct downstream signaling molecule of phosphatidylinositol 3-kinase (PI3K), but upstream of glycogen synthase kinase-3β (GSK-3β) and cAMP response element-binding protein (CREB). These augmentations and neurite-bearing cells induced by emodin were remarkably reduced by the addition of PI3K inhibitor LY294002. These results demonstrate that emodin induces neuronal differentiation of Neuro2a cells via PI3K/Akt/GSK-3β pathway.