Cognitive Improving and Cerebral Protective Effects of Acylated Oligosaccharides in Polygala tenuifolia

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Multi-target regulatory mechanism of Yang Xin Tang - a traditional Chinese medicine against dementia

BACKGROUND

Yang Xin Tang (YXT) is a traditional Chinese herbal preparation which has been reported to improve cognitive function and memory in patients with dementia. As the underlying mechanism of action of YXT has not been elucidated, we examined the effects of YXT and its major herbal components in regulating gene transcription and molecular targets related to Alzheimer's disease (AD).

METHODS

Aqueous and ethanol extracts of YXT and selected herbal components were prepared and validated by standard methods. A series of biochemical and cellular assays were employed to assess the ability of the herbal extracts to inhibit acetylcholinesterase, reduce β-amyloid aggregation, stimulate the differentiation of neural progenitor cells, suppress cyclooxygenase, and protect neurons against β-amyloid or N-methyl-D-aspartate-induced cytotoxicity. The effects of YXT on multiple molecular targets were further corroborated by a panel of nine reporter gene assays.

RESULTS

Extracts of YXT and two of its constituent herbs, Poria cocos and Poria Sclerotium pararadicis, significantly inhibited β-amyloid aggregation and β-amyloid-induced cytotoxicity. A protective effect of the YXT extract was similarly observed against N-methyl-D-aspartate-induced cytotoxicity in primary neurons, and this activity was shared by extracts of Radix Astragali and Rhizoma Chuanxiong. Although the YXT extract was ineffective, extracts of Poria cocos, Poria Sclerotium pararadicis and Radix Polygalae inhibited acetylcholine esterase, with the latter also capable of upregulating choline acetyltransferase. YXT and its components significantly inhibited the activities of the pro-inflammatory cyclooxygenases. Additionally, extracts of YXT and several of its constituent herbs significantly stimulated the phosphorylation of extracellular signal-regulated kinases and cAMP-responsive element binding protein, two molecular targets involved in learning and memory, as well as in the regulation of neurogenesis.

CONCLUSIONS

Several constituents of YXT possess multiple regulatory effects on known therapeutic targets of AD that range from β-amyloid to acetylcholinesterase. The demonstrated neuroprotective and neurogenic actions of YXT lend credence to its use as an alternative medicine for treating AD.

Rapid characterization of chemical constituents in Naoling Pian by LC-MS combined with data processing techniques

Naoling Pian is a prescription composed of 15 herbs, which is mainly used for the treatment of insomnia in clinical practice. However, the chemical constituents in Naoling Pian are numerous and unclear, which hinders the interpretation of its bioactive constituents and the subsequent research on the material basis for pharmacodynamics. The purpose of this study is to develop a rapid method for identifying the chemical constituents of Naoling Pian using high-throughput ultra-performance liquid chromatography quadrupole time of flight coupled with mass spectrometry combined with a software platform for data processing. The whole composition of Naoling Pian was characterized in positive and negative ion modes. In this experiment, an overall total of 201 constituents were identified by using reference standards, online and self-built databases matching, fragmentation rules analysis of mass spectrometry peaks with a software platform. Meanwhile, Naoling Pian was analyzed for the first time using LC-MS method, the constituents could be identified in a quick and accurate manner, and the results could provide a scientific basis for the follow-up research on the pharmacodynamic material basis and quality control of Naoling Pian. This article is protected by copyright. All rights reserved.

3,6'-disinapoyl sucrose attenuates Aβ1-42 - induced neurotoxicity in Caenorhabditis elegans by enhancing antioxidation and regulating autophagy

The aggregation of β‐amyloid (Aβ) has the neurotoxicity, which is thought to play critical role in the pathogenesis of Alzheimer's disease (AD). Inhibiting Aβ deposition and neurotoxicity has been considered as an important strategy for AD treatment. 3,6'‐Disinapoyl sucrose (DISS), one of the oligosaccharide esters derived from traditional Chinese medicine Polygalae Radix, possesses antioxidative activity, neuroprotective effect and anti‐depressive activity. This study was to explore whether DISS could attenuate the pathological changes of Aβ_1‐42 transgenic Caenorhabditis elegans (C. elegans). The results showed that DISS (5 and 50 μM) treatment significantly prolonged the life span, increased the number of egg‐laying, reduced paralysis rate, decreased the levels of lipofuscin and ROS and attenuated Aβ deposition in Aβ_1‐42 transgenic C. elegans. Gene analysis showed that DISS could up‐regulate the mRNA expression of sod‐3, gst‐4, daf‐16, bec‐1 and lgg‐1, while down‐regulate the mRNA expression of daf‐2 and daf‐15 in Aβ_1‐42 transgenic C. elegans. These results suggested that DISS has the protective effect against Aβ_1‐42‐induced pathological damages and prolongs the life span of C. elegans, which may be related to the reduction of Aβ deposition and neurotoxicity by regulating expression of genes related to antioxidation and autophagy.

Oligosaccharides from Traditional Chinese Herbal Medicines: A Review of Chemical Diversity and Biological Activities

Most of traditional Chinese herbal medicine (TCHM) substances come from medicinal plants, among which oligosaccharides have gradually attracted widespread attention at home and abroad due to their important biological activities and great medicinal potential. Numerous in vitro and in vivo experiments exhibited that oligosaccharides possess various activities, such as antitumor, anti-oxidation, modulate the gut microflora, anti-inflammatory, anti-infection, and immune-regulatory activities. Generally, biological activities are closely related to chemical structures, including molecular weight, monosaccharide composition, glycosidic bond connection, etc. The structural analysis of oligosaccharides is an important basis for studying their structure-activity relationship, but the structural diversity and complexity of carbohydrate compounds limit the study of oligosaccharides activities. Understanding the structures and biological functions of oligosaccharides is important for the development of new bioactive substances with natural oligosaccharides. This review provides a systematic introduction of the current knowledge of the chemical structures and biological activities of oligosaccharides. Most importantly, the reported chemical characteristics and biological activities of the famous TCHM oligosaccharides were briefly summarized, including Morinda officinalis, Rehmannia glutinosa, Arctium lappa, Polygala tenuifolia, Panax ginseng, Lycium barbarum and Astragalus membranaceus. TCHM oligosaccharides play an important role in nutrition, health care, disease diagnosis and prevention as well as have broad application prospects in the field of medicine.

Protective Effects and Mechanism of Radix Polygalae Against Neurological Diseases as Well as Effective Substance

Radix Polygalae (also known as Yuanzhi in China) is the dried rhizome of Polygala tenuifolia Willd. or Polygala sibirica L., which is a famous Chinese herb and has been widely used for centuries in traditional medicines including expectorants, tonics, tranquilizers, antipsychotic, and so on. This article reviews the neuroprotective effects of Radix Polygalae in preclinical models of central nervous system (CNS) disorders, especially anxiety, depression, declining cognition, Alzheimer's disease (AD), and Parkinson's disease (PD). The chemical composition of Radix Polygalae as well as the underlying mechanisms of action were also reviewed. We found that Radix Polygalae possesses a broad range of beneficial effects on the abovementioned conditions. The multifold mechanisms of action include several properties such as antioxidant and associated apoptotic effects; anti-inflammatory and associated apoptotic effects; neurogenesis, regeneration, differentiation, and neuronal plasticity improvement; hypothalamic-pituitary-adrenal axis (HPA) regulation; neurotransmitter release; and receptor activation (A_2AR, NMDA-R, and GluR). Nevertheless, the detailed mechanisms underlying this array of pharmacological effects observed in vitro and in vivo still need further investigation to attain a coherent neuroprotective profile.

Neuroprotective Effects of Medicinal Plants in Cerebral Hypoxia and Anoxia: A Systematic Review

Background:

Hypoxia and anoxia are dangerous and sometimes irreversible complications in the central nervous system (CNS), which in some cases lead to death.

Objective:

The aim of this review was to investigate the neuroprotective effects of medicinal plants in cerebral hypoxia and anoxia.

Methods:

The word hypox*, in combination with some herbal terms such as medicinal plant, phyto* and herb*, was used to search for relevant publications indexed in the Institute for Scientific Information (ISI) and PubMed from 2000-2019.

Results:

Certain medicinal plants and herbal derivatives can exert their protective effects in several ways. The most important mechanisms are the inhibition of inducible nitric oxide synthase (iNOS), production of NO, inhibition of both hypoxia-inducible factor 1α and tumor necrosis factor-alpha activation, and reduction of extracellular glutamate, N-Methyl-D-aspartic and intracellular Ca (2+). In addition, they have an antioxidant activity and can adjust the expression of genes related to oxidant generation or antioxidant capacity. These plants can also inhibit lipid peroxidation, up-regulate superoxide dismutase activity and inhibit the content of malondialdehyde and lactate dehydrogenase. Moreover, they also have protective effects against cytotoxicity through down-regulation of the proteins that causes apoptosis, anti-excitatory activity, inhibition of apoptosis signaling pathway, reduction of pro-apoptotic proteins, and endoplasmic reticulum stress that causes apoptosis during hypoxia, increasing anti-apoptotic protein, inhibition of protein tyrosine kinase activation, decreasing proteases activity and DNA fragmentation, and upregulation of mitochondrial cytochrome oxidase.

Conclusion:

The results indicated that medicinal plants and their compounds mainly exert their neuroprotective effects in hypoxia via regulating proteins that are related to antioxidant, anti-apoptosis and anti-inflammatory activities.

Intestinal Absorption Profile of Three Polygala Oligosaccharide Esters in Polygalae Radix and the Effects of Other Components in Polygalae Radix on Their Absorption

Oligosaccharide esters, which are among the main active components of Polygalae Radix (PR), demonstrate significant pharmacological activities in the human nervous system. In our previous research, some other constituents in PR were able to improve the bioavailability of oligosaccharide esters such as sibiricose A5 (SA5), sibiricose A6 (SA6), and 3,6'-disinapoyl sucrose (DISS), but the related components and their underlying mechanisms remain unknown. The present study aimed to investigate the intestinal absorptive profile of SA5, SA6, and DISS and the absorptive behavior influenced by the coadministration of polygalaxanthone III and total saponins of PR (TS) using an in vitro everted rat gut sac model, along with the possible mechanisms that may influence absorption. The results showed that TS could significantly enhance the absorption of SA5, SA6, and DISS monomers. Verapamil, a P-glycoprotein inhibitor, was able to elevate the absorption of SA5 and SA6, and an absorption experiment using Rho123 led us to conclude that TS influenced the absorption of SA5 and SA6 in a manner similar to that of a P-glycoprotein inhibitor. Sodium caprate, a paracellular absorption enhancer, was found to increase the absorption of SA5, SA6, and DISS. Results showed that the absorption mechanisms of SA5 and SA6 may combine active transport with paracellular passive penetration, while DISS's absorption was dominated by paracellular passive penetration. However, the relationship between polygala saponins and the absorption of SA5, SA6, and DISS by paracellular passive penetration remain to be examined. This is the direction of our future research.

Research progress in the biological activities of 3,4,5-trimethoxycinnamic acid (TMCA) derivatives

TMCA (3,4,5-trimethoxycinnamic acid) ester and amide are privileged structural scaffolds in drug discovery which are widely distributed in natural products and consequently produced diverse therapeutically relevant pharmacological functions. Owing to the potential of TMCA ester and amide analogues as therapeutic agents, researches on chemical syntheses and modifications have been carried out to drug-like candidates with broad range of medicinal properties such as antitumor, antiviral, CNS (central nervous system) agents, antimicrobial, anti-inflammatory and hematologic agents for a long time. At the same time, SAR (structure-activity relationship) studies have draw greater attention among medicinal chemists, and many of the lead compounds were derived for various disease targets. However, there is an urgent need for the medicinal chemists to further exploit the precursor in developing chemical entities with promising bioactivity and druggability. This review concisely summarizes the synthesis and biological activity for TMCA ester and amide analogues. It also comprehensively reveals the relationship of significant biological activities along with SAR studies.

•

3,4,5-Trimethoxycinnamic acid (TMCA) derivatives show applications in different pathophysiological conditions due to its privileged structural scaffolds.

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Natural derived TMCA analogues and chemically modified TMCA ester and amide analogues and their bioactivities are focused in this review. Additionally, it also comprehensively summarized the relationship of significant biological activities along with SAR studies of synthetic TMCA derivatives.

Study on the safety of Polygala tenuifolia Willdenow root extract powder (BT-11) in young person aged from 9 to 19 years old

ETHNOPHARMACOLOGICAL RELEVANCE

Polygala tenuifolia Willdenow root extract (BT-11) has beneficial effects on central nervous system disorders in human. The safety of BT-11 should be elucidated in younger person further.

AIM OF THE STUDY

To evaluate the safety of BT-11 in human aged from 9 to 19 years old.

MATERIAL AND METHODS

The safety was evaluated in randomly assigned subjects who received the test products (61 subjects in BT-11 300 mg daily or 60 subjects in matching placebo) for 12 weeks. Adverse reactions were analyzed by the incidence rate, type, and severity. The clinical examination included hematology and blood chemistry tests, urinalysis, vital signs, body weight, and electrocardiogram (ECG).

RESULTS

Eleven adverse reactions were observed in ten subjects receiving BT-11 while seven adverse reactions in six subjects receiving placebo. There were no statistical differences in the incidence of adverse reactions between the two groups. Serious adverse reactions such as acute appendicitis and acute viral gastroenteritis were observed in the BT-11 group4 and the placebo group, respectively. However, it was confirmed that they were not associated with the test product. All other adverse reactions observed during the test period were resolved completely without special treatment. No statistical difference was also observed in safety laboratory tests, vital signs, and ECG between two groups.

CONCLUSIONS

This study demonstrates the safety of BT-11 in the adolescent by showing no apparent adverse reactions related to it.

Jia-Wei-Kai-Xin-San, an Herbal Medicine Formula, Ameliorates Cognitive Deficits via Modulating Metabolism of Beta Amyloid Protein and Neurotrophic Factors in Hippocampus of Aβ1-42 Induced Cognitive Deficit Mice

Jia-Wei-Kai-Xin-San (JWKXS) is a Chinese medicine formula applied for treating morbid forgetfulness in ancient China. Today, this formula is frequently applied for Alzheimer's disease and vascular dementia (VD) in clinic. Here, we developed it as granules and aimed to evaluate its anti-AD effect on β amyloid protein 1-42 (Aβ1-42) induced cognitive deficit mice and reveal the possible molecular mechanisms. Firstly, daily intra-gastric administration of chemically standardized of JWKXS granules for 7 days significantly ameliorated the cognitive deficit symptoms and inhibited cell apoptosis in hippocampus on Aβ1-42 injection mice. JWKXS granules significantly decreased Aβ level, increased superoxide dismutase activity and decreased malondialdehyde level in hippocampus of model mice. It also restored acetylcholine amounts, inhibited acetylcholinesterase activities and increased choline acetyltransferase activities. In addition, JWKXS granules enabled the transformation of precursors of NGF and BDNF into mature forms. Furthermore, JWKXS granules could regulate gene expressions related to Aβ production, transportation, degradation and neurotrophic factor transformation, which led to down-regulation of Aβ and up-regulation of NGF and BDNF. These findings suggested that JWKXS granules ameliorated cognitive deficit via decreasing Aβ levels, protecting neuron from oxidation damages and nourishing neuron, which could serve as alternative medicine for patients suffering from AD.

Characterization of UV-Sensitive Marker Constituents of Polygala Root for TLC: Applications in Quality Control of Single Crude Drug Extract Preparations

Polygala Root (the root of Polygala tenuifolia WILLDENOW; Japanese name "Onji"), a well-known crude drug, traditionally used as an expectorant and sedative, has been attracting increased interest in recent years owing to its newly found pharmacological effect related to neuroprotection. However, there is no specific method for identifying and estimating the quality of this crude drug in the Japanese Pharmacopoeia, 17th edition. Therefore, in order to develop a TLC-based simple and convenient identification method using characteristic chemical marker(s) for the drug and its extract products, UV-sensitive constituents of Polygala Root were first investigated. A total of 23 aromatic compounds were isolated and characterized. Two new compounds, namely, polygalaonjisides A (1) and B (2), were characterized as syringic acid 4-O-(2'-O-β-D-apiosyl)-β-D-glucoside and 2-O-(β-D-glucosyl)-3'-O-benzoylsucrose, respectively. Based on these phytochemical results, a TLC method focusing on three marker spots with Rf value of approximately 0.4-0.5 due to tenuifolisides A and B and 3,6'-di-O-sinapoylsucrose was proposed as a simple and convenient test to identify Polygala Root or its single-extract products on the market. The data presented in this paper could be useful in stipulating a confirmation test to identify Polygala Root.

UHPLC-MS/MS method for simultaneous determination of Radix Polygalae glycolipids and organic acids in rat plasma and application in a pharmacokinetic study

Radix Polygala (Yuanzhi in Chinese) is well-known in traditional Chinese medicine (TCM) and has been used for treatment of depression, brain protection, and memory improvement for thousands of years. This plant medicine is rich in saponins, glycolipids, and organic acids. The purpose of the current study was to develop a rapid, accurate, and sensitive ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of the following seven active components of Radix Polygala extracts in rat plasma: sibiricose A5 (A5); sibiricose A6 (A6); 3,6'-disinapoyl sucrose (DSS); tenuifoliside A (TFSA); tenuifoliside B (TFSB); tenuifoliside C (TFSC); and 3,4,5-trimethoxycinnamic acid (TMCA). Then, the pharmacokinetics were studied following oral administration. Plasma samples were precipitated with methanol. Chromatographic separation was successfully performed on a thermo C₁₈ column (100 × 3.0 mm, 3 μm) with a mobile phase consisting of acetonitrile and 10 mmol/L of an ammonium acetate aqueous solution. Seven analytes were detected by multiple reaction monitoring (MRM) with an electrospray ionization source in the positive mode. The transitions of m/z were 517.1/174.9, 547.0/204.9, 753.2/205.2, 681.3/443.3, 667.2/205.1, 767.4/529.2, 236.8/103.2, and 136.9/92.9 for A5, A6, DSS, TFSA, TFSB, TFSC, TMCA, and salicylic acid (IS), respectively. The method validation showed good linearity in the range of 1-2000 ng/mL and LLOQs of 1 ng/mL for the 7 components in plasma. The accuracy, precision, and stability of QC samples were all within allowable ranges. In addition, no significant matrix effect was observed using this method. For the first time, the validated method has been successfully applied to the pharmacokinetic study of the seven components of Radix Polygala extracts in rat plasma. Moreover, this method may be applied for detecting prescriptions that contain Radix Polygala or other plant medicines that include one or more components above. The results of the pharmacokinetic study of the seven ingredients will provide important guidance to clinical medicine regarding Radix Polygala and prescriptions include Radix Polygala.

Illumination on "Reserving Phloem and Discarding Xylem" and Quality Evaluation of Radix polygalae by Determining Oligosaccharide Esters, Saponins, and Xanthones

The root of Polygala tenuifolia Willd. or Polygala sibirica L. exhibits protective effects on the central nervous system and is frequently used to treat insomnia, amnesia, and other cognitive dysfunction. In our study, we studied nine bioactive compounds spanning oligosaccharide esters, saponins, and xanthones by using a sensitive, efficient, and validated method established on ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry. The quantified result of interesting compounds proved that accumulation of those compounds were found in phloem rather than in xylem. By taking the standardized result of nine compound contents into account, the “Spider-web” analytical result of xylem and phloem from Radix polygalae (RP) unveiled the rationality of RP’s classical use in clinic including discarding the xylem and reserving the phloem. Moreover, the remarkable variation was also revealed from the quantitative result of 45 samples with different diameters from the different origins, which did not significantly correlate with the variation of RP’s diameter. Our study could shed the light on the quality assessment of RP for further research and illustrate the scientific connotation of the processing method of “discarding the xylem and reserving the phloem”.

Synergistic effect of Korean red ginseng and Pueraria montana var. lobata against trimethyltin-induced cognitive impairment

Many edible plant extracts exhibit biological activities. For example, the ethanol extract of Pueraria montana var. lobata (P. montana) inhibits acetylcholinesterase (AChE), and red ginseng is well known for promoting health. In this study the authors investigated the synergistic effect of P. montana and red ginseng extracts on AChE activity in vitro and in mouse brain tissues and trimethyltin (TMT)-induced cognitive impairment in a mouse model of TMT-induced neurodegeneration. A diet containing a mixture of P. montana and red ginseng extracts reversed learning and memory impairments in Y-maze and passive avoidance behavioral tests. In addition, the mixture inhibited AChE activity and lipid peroxidation synergistically.

Determination of the phytochemical composition of Jingning fang and the in vivo pharmacokinetics of its metabolites in rat plasma by UPLC-MS/MS

Jingning fang (JNF) is an effective Traditional Chinese Medicine (TCM) which is used for the treatment of Attention Deficit Hyperactivity Disorder (ADHD). To clarify the bioactive constituents of JNF, a Thermo Q Exactive™ Plus Orbitrap™ mass spectrometer was used in this study. More than 127 chemical compounds were isolated and identified tentatively in the JNF extract, while 42 prototype constituents with 4 potential metabolites were identified tentatively in rat plasma. A method for simultaneous determination of polygalaxanthone III (PAIII), sibiricose A5 (A5), sibiricose A6 (A6), 3, 6'-disinapoyl sucrose (3,6'-DISS), tenuifoliside C (TEC), tenuifolin B (TNB), verbascoside (VCE), heterophyllin B (HEB) and schisandrin (SCH) in rat was developed and validated using polydatin (PLN) and psoralen (PSN) as internal standards. All calibration curves proved favorable linearity (R2≥0.9923) in linear ranges. The lower limit of quantification (LLOQ) was 2.5ng/mL for PAIII, A5, 3, 6'-DISS, TNB, VCE, HEB and SCH, 1.0ng/mL for A6 and TEC, respectively. Intra-day and inter-day precisions didn't exceed 14.0% for all the analytes. Extraction recoveries and matrix effects of analytes and IS were acceptable. The validated method has been successfully applied to the pharmacokinetics (PK) studies of the nine compounds in JNF. These findings are useful for predicting the bioactive components of JNF, and will aid in optimizing dose regimens of the drug.

Utilization of UPLC/Q-TOF-MS-Based Metabolomics and AFLP-Based Marker-Assisted Selection to Facilitate/Assist Conventional Breeding of Polygala tenuifolia

As one of the most important traditional Chinese medicine, the quality of Polygala tenuifolia is difficult to control and a new method must be established to facilitate/assist the breeding of P. tenuifolia. In this study, UPLC/Q-TOF-MS-based metabolomics analysis was performed to determine the chemical composition and screen metabolite biomarkers according to agronomic traits. A total of 29 compounds and 18 metabolite biomarkers were found. AFLP-based marker-assisted selection (MAS) was used to identify molecular marker bands and screen characteristic bands associated with specific agronomic traits. 184 bands and 76 characteristic AFLP bands were found. The correlation network between compounds and characteristic AFLP bands was built, so we may directly breed certain P. tenuifolia herbs with special agronomic traits (or characteristic AFLP bands), which exhibit specific pharmacological functions depending on the content of the active compounds. The proposed method of metabolomics coupled with MAS could facilitate/assist the breeding of P. tenuifolia.

Cognitive-enhancing effects of hydrolysate of polygalasaponin in SAMP8 mice

OBJECTIVES

The aim of the study is to evaluate the cognitive-enhancing effects of hydrolysate of polygalasaponin (HPS) on senescence accelerate mouse P8 (SAMP8) mice, an effective Alzheimer's disease (AD) model, and to research the relevant mechanisms.

METHODS

The cognitive-enhancing effects of HPS on SAMP8 mice were assessed using Morris water maze (MWM) and step-through passive avoidance tests. Then N-methyl-D-aspartate (NMDA) receptor subunit expression for both the cortex and hippocampus of mice was observed using Western blotting.

RESULTS

HPS (25 and 50 mg/kg) improved the escape rate and decreased the escape latency and time spent in the target quadrant for the SAMP8 mice in the MWM after oral administration of HPS for 10 d. Moreover, it decreased error times in the passive avoidance tests. Western blotting showed that HPS was able to reverse the levels of NMDAR1 and NMDAR2B expression in the cortex or hippocampus of model mice.

CONCLUSIONS

The present study suggested that HPS can improve cognitive deficits in SAMP8 mice, and this mechanism might be associated with NMDA receptor (NMDAR)-related pathways.

Treatment of Insomnia With Traditional Chinese Herbal Medicine

Insomnia is a condition with sleep problems and many people suffered from it. Chronic insomnia can last for long time and it will severely affect people's health and the quality of life. In conventional medicine, the most commonly used the medicine is benzodiazepine. It is effective but also has significant side effects. Patients try to use some kinds of alternative medicines. Chinese medicinal herbs and formulas have been used in the treatment of insomnia for more than 2000 years in China. In recent decades, Chinese herbal medicine has been widely used in the Western countries. Many clinical studies including randomized controlled clinical trials and research on pharmacological action mechanisms of the herbs for treatment of insomnia have been conducted. It is very important and very helpful to review the published research papers to gather the available information for a critical analysis. This chapter evaluated the data from both of clinical studies and pharmacological researches on the therapeutic formulas and on some key herbs used in the treatment of insomnia. Clinical studies showed a very wide spectrum of herbs that were used in clinical treatment of insomnia. This was due to different syndrome patterns happened with insomnia. This brought complexity and difficulties to identify which are the essential key herbs or formulas. It was found Suanzaoren decoction (Ziziphus spinose decoction ) is the most frequently used formula for the treatment of insomnia. Based on the clinical data, several herbs were identified as most frequently used sedative and hypnotic herbs in Chinese herbal medicine including Suanzaoren (Ziziphus spinose ), Fuling (Poria cocos ), and Gancao (Glycyrrhiza uralensis ). The underlying pharmacological action mechanisms discovered in the studies on some key herbs used in the treatment of insomnia were evaluated. The major pharmacological action mechanisms shared by most of the sedative herbs are to act through the neurotransmitter gamma-aminobutyric acid (GABA) or via stimulation of GABAA_A receptor. Some herbs exert sedative activities via inhibition of 5-hydroxytryptamine 1A receptor. Another mechanism shown by some herbs is to upregulate the expression of orexin-A, leptin, orexin receptor-1, and leptin receptor in the brain, reducing insomnia-induced negative consequences, and thus indirectly help improvement of insomnia.

Traditional Mediterranean and European herbal medicines

ETHNOPHARMACOLOGICAL RELEVANCE

Written history allows tracing back Mediterranean and European medical traditions to Greek antiquity. The epidemiological shift triggered by the rise of modern medicine and industrialization is reflected in contemporary reliance and preferences for certain herbal medicines.

MATERIALS AND METHODS

We sketch the development and transmission of written herbal medicine through Mediterranean and European history and point out the opportunity to connect with modern traditions.

RESULTS

An ethnopharmacological database linking past and modern medical traditions could serve as a tool for crosschecking contemporary ethnopharmacological field-data as well as a repository for data mining. Considering that the diachronic picture emerging from such a database has an epidemiological base this could lead to new hypotheses related to evolutionary medicine.

CONCLUSION

The advent of systems pharmacology and network pharmacology opens new perspectives for studying past and current herbal medicine. Since a large part of modern drugs has its roots in ancient traditions one may expect new leads for drug development from novel systemic studies, as well as evidence for the activity of certain herbal preparations.

Naturally Occurring Cinnamic Acid Sugar Ester Derivatives

Cinnamic acid sugar ester derivatives (CASEDs) are a class of natural product with one or several phenylacrylic moieties linked with the non-anomeric carbon of a glycosyl skeleton part through ester bonds. Their notable anti-depressant and brains protective activities have made them a topic of great interest over the past several decades. In particular the compound 3′,6-disinapoylsucrose, the index component of Yuanzhi (a well-known Traditional Chinese Medicine or TCM), presents antidepressant effects at a molecular level, and has become a hotspot of research on new lead drug compounds. Several other similar cinnamic acid sugar ester derivatives are reported in traditional medicine as compounds to calm the nerves and display anti-depression and neuroprotective activity. Interestingly, more than one third of CASEDs are distributed in the family Polygalaceae. This overview discusses the isolation of cinnamic acid sugar ester derivatives from plants, together with a systematic discussion of their distribution, chemical structures and properties and pharmacological activities, with the hope of providing references for natural product researchers and draw attention to these interesting compounds.

Polygalasaponin XXXII, a triterpenoid saponin from Polygalae Radix, attenuates scopolamine-induced cognitive impairments in mice

AIM

Recent studies show that the extract of a Chinese herb Polygalae Radix exerts cognition-enhancing actions in rats and humans. The aim of this study was to characterize the pharmacological profiles of active compounds extracted from Polygalae Radix.

METHODS

Two fractions P3 and P6 and two compounds PTM-15 and polygalasaponin XXXII (PGS32) were prepared. Neuroprotective effects were evaluated in primary cortical neurons exposed to high concentration glutamate, serum deficiency or H2O2. Anti-dementia actions were assessed in scopolamine-induced amnesia in mice using step-through avoidance tests and channel water maze tests. After conducting the channel water maze tests, TrkB phosphorylation in mouse hippocampus was detected using Western blotting. Long-term potentiation (LTP) was induced in the dentate gyrus in adult rats; PGS32 (5 μL 400 μmol/L) was injected into the lateral cerebral ventricle 20 min after high frequency stimulation (HFS).

RESULTS

Compared to the fraction P6, the fraction P3 showed more prominent neuroprotective effects in vitro and cognition-enhancing effects in scopolamine-induced amnesia in mice. One active compound PGS32 in the fraction P3 exerted potent cognition-enhancing action: oral administration of PGS32 (0.125 mg·kg(-1)·d(-1)) for 19 days abolished scopolamine-induced memory impairment in mice. Furthermore, PGS32 (0.5 and 2 mg·kg(-1)·d(-1)) significantly stimulated the phosphorylation of TrkB in the hippocampus. Intracerebroventricular injection of PGS32 significantly enhanced HFS-induced LTP in the dentate gyrus of rats.

CONCLUSION

PGS32 attenuates scopolamine-induced cognitive impairments in mice, suggesting that it has a potential for the treatment of cognitive dysfunction and dementia.

TCM, brain function and drug space

Covering: up to 2015. Traditional Chinese medicine has played a significant role in the mainstream healthcare system in China for thousands of years. Here, we summarize 84 major compounds from 15 selected herbal medicines targeting neurodegenerative diseases. We present a perspective based on the analysis of physicochemical properties of these TCM compounds, and comparison with current drugs and candidates for the treatment of Parkinson's and Alzheimer's disease. The results demonstrate that traditional Chinese medicines contain compounds possessing physicochemical properties that have excellent overlap with developed western medicines.

Analysis of Polygala tenuifolia Transcriptome and Description of Secondary Metabolite Biosynthetic Pathways by Illumina Sequencing

Radix polygalae, the dried roots of Polygala tenuifolia and P. sibirica, is one of the most well-known traditional Chinese medicinal plants. Radix polygalae contains various saponins, xanthones, and oligosaccharide esters and these compounds are responsible for several pharmacological properties. To provide basic breeding information, enhance molecular biological analysis, and determine secondary metabolite biosynthetic pathways of P. tenuifolia, we applied Illumina sequencing technology and de novo assembly. We also applied this technique to gain an overview of P. tenuifolia transcriptome from samples with different years. Using Illumina sequencing, approximately 67.2% of unique sequences were annotated by basic local alignment search tool similarity searches against public sequence databases. We classified the annotated unigenes by using Nr, Nt, GO, COG, and KEGG databases compared with NCBI. We also obtained many candidates CYP450s and UGTs by the analysis of genes in the secondary metabolite biosynthetic pathways, including putative terpenoid backbone and phenylpropanoid biosynthesis pathway. With this transcriptome sequencing, future genetic and genomics studies related to the molecular mechanisms associated with the chemical composition of P. tenuifolia may be improved. Genes involved in the enrichment of secondary metabolite biosynthesis-related pathways could enhance the potential applications of P. tenuifolia in pharmaceutical industries.

An update on oligosaccharides and their esters from traditional chinese medicines: chemical structures and biological activities

A great number of naturally occurring oligosaccharides and oligosaccharide esters have been isolated from traditional Chinese medicinal plants, which are used widely in Asia and show prominent curative effects in the prevention and treatment of kinds of diseases. Numerous in vitro and in vivo experiments have revealed that oligosaccharides and their esters exhibited various activities, including antioxidant, antidepressant, cytotoxic, antineoplastic, anti-inflammatory, neuroprotective, cerebral protective, antidiabetic, plant growth-regulatory, and immunopotentiating activities. This review summarizes the investigations on the distribution, chemical structures, and bioactivities of natural oligosaccharides and their esters from traditional Chinese medicines between 2003 and 2013.

Quality analysis of Polygala tenuifolia root by ultrahigh performance liquid chromatography–tandem mass spectrometry and gas chromatography–mass spectrometry

Polygala tenuifolia root is used as a functional food due to its attractive health benefits. In this study, ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) and gas chromatography–mass spectrometry (GC-MS) were utilized to characterize the bioactive compounds in P. tenuifolia root. The UPLC-MS/MS information revealed 36 bioactive compounds, including oligosaccharide esters, polygalasaponins, and polygalaxanthones. GC-MS identified 34 volatile compounds with fatty acids as the main chemicals. The leading compound judged by UPLC-MS/MS was tenuifoliside A, and oleic acid was the leading volatile from GC-MS profiles. All samples tested showed similar bioactive compound compositions, but the level of each compound varied. Principal component analysis revealed the principal bioactive compounds with significant level variations between samples. These principal chemicals could be used for quality judgment of P. tenuifolia root, instead of measuring the levels of all compositional compounds.

Antioxidant and anti-inflammatory activities of zinc oxide nanoparticles synthesized using Polygala tenuifolia root extract

The exploitation of various plant materials for the green synthesis of nanoparticles is considered an eco-friendly technology because it does not involve toxic chemicals. In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized using the root extract of Polygala tenuifolia. Synthesized ZnO NPs were characterized by UV-Vis spectroscopy, FTIR, TGA, TEM, SEM and EDX. Anti-inflammatory activity was investigated in LPS-stimulated RAW 264.7 macrophages, whereas antioxidant activity was examined using a DPPH free radical assay. ZnO NPs demonstrated moderate antioxidant activity by scavenging 45.47% DPPH at 1mg/mL and revealed excellent anti-inflammatory activity by dose-dependently suppressing both mRNA and protein expressions of iNOS, COX-2, IL-1β, IL-6 and TNF-α.

Tenuifolin, a secondary saponin from hydrolysates of polygalasaponins, counteracts the neurotoxicity induced by Aβ25-35 peptides in vitro and in vivo

Alzheimer's disease (AD) is associated with damage to hippocampal neurons and declines in cognitive functions. The accumulation of amyloid peptides is regarded as a crucial event in the initiation of AD. The neurotoxicity induced by Aβ25-35 peptides was used to screen for cytoprotective factors in vitro, and the cognitive deficits induced by the injection of Aβ25-35 into the hippocampus were used to evaluate effect on learning and memory. Our previous study revealed that hydrolysate of polygalasaponins (HPS) clearly improve the cognitive deficits induced by the injection of Aβ25-35 in mice, but the potential active constituent of HPS remains unclear. The purposes of this study were to separate and purify the secondary saponins of HPS, screen for neuroprotective effects of the constituents in vitro, and to evaluate the effect of cognition in vivo. Various chromatographic methods were used to separate and purify the HPS. The neuroprotective effects were examined in Aβ25-35-damage-induced PC12 cells. The protective effect of tenuifolin on the cognitive impairments induced by Aβ25-35 injection was assessed using the Morris water maze and step-through passive avoidance tests. Tenuifolin and fallaxsaponin A were isolated from the HPS. Tenuifolin possessed neuroprotective effects against Aβ25-35-induced apoptosis in PC12 cells and significantly improved the cognitive deficits induced by the intrahippocampal injection of Aβ25-35 in mice. Thus, tenuifolin is one of the active constituents of HPS against the neurotoxicity induced by Aβ25-35 peptides in vitro and in vivo.

Preclinical Safety of the Root Extract of Polygala tenuifolia Willdenow in Sprague-Dawley Rats and Beagle Dogs

The root of Polygala tenuifolia Willdenow has been used for the treatment of insomnia, depression, and amnesia. However, the toxicological properties of the herb have been overlooked, because it has been used for a long time for various purposes. In this study, we evaluated the preclinical safety of the root extract in rats and beagle dogs. First, the acute oral toxicity was tested in both rats and dogs. In the rats, only one female of 2 g/kg died, but no treatment-related death or clinical and gross findings were observed after the administration. No toxicological changes or mortalities related to the test substance were also observed after the administration in the dogs. Although vomiting, discoloration, or hemorrhage was found in some dogs, there were no serious abnormalities. Second, the subchronic toxicity was investigated in the rats. Two animals were found dead in the female group of 1,000 mg/kg/day, but there were no abnormal findings associated with the test substance. There also were no adverse effects on the clinical signs, body weight, and hematological and biochemical findings. Therefore, our results showed that the acute or subchronic toxicity of the root extract of Polygala tenuifolia might not be toxic to rats and dogs.

UPLC/Q-TOF MS-based metabolomics and qRT-PCR in enzyme gene screening with key role in triterpenoid saponin biosynthesis of Polygala tenuifolia

BACKGROUND

The dried root of Polygala tenuifolia, named Radix Polygalae, is a well-known traditional Chinese medicine. Triterpenoid saponins are some of the most important components of Radix Polygalae extracts and are widely studied because of their valuable pharmacological properties. However, the relationship between gene expression and triterpenoid saponin biosynthesis in P. tenuifolia is unclear.

METHODOLOGY/FINDINGS

In this study, ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF MS)-based metabolomic analysis was performed to identify and quantify the different chemical constituents of the roots, stems, leaves, and seeds of P. tenuifolia. A total of 22 marker compounds (VIP>1) were explored, and significant differences in all 7 triterpenoid saponins among the different tissues were found. We also observed an efficient reference gene GAPDH for different tissues in this plant and determined the expression level of some genes in the triterpenoid saponin biosynthetic pathway. Results showed that MVA pathway has more important functions in the triterpenoid saponin biosynthesis of P. tenuifolia. The expression levels of squalene synthase (SQS), squalene monooxygenase (SQE), and beta-amyrin synthase (β-AS) were highly correlated with the peak area intensity of triterpenoid saponins compared with data from UPLC/Q-TOF MS-based metabolomic analysis.

CONCLUSIONS/SIGNIFICANCE

This finding suggested that a combination of UPLC/Q-TOF MS-based metabolomics and gene expression analysis can effectively elucidate the mechanism of triterpenoid saponin biosynthesis and can provide useful information on gene discovery. These findings can serve as a reference for using the overexpression of genes encoding for SQS, SQE, and/or β-AS to increase the triterpenoid saponin production of P. tenuifolia.

The discovery of Yuanzhi-1, a triterpenoid saponin derived from the traditional Chinese medicine, has antidepressant-like activity

Yuanzhi, the dried root of Polygala tenuifolia Willd., is a well-known traditional Chinese medicine used for its sedative, antipsychotic, cognitive improving, neuroprotective, and antidepressant effects. The present study was designed to screen and identify the antidepressant-like effect of six triterpenoid saponin components derived from Yuanzhi (Yuanzhi-1 to Yuanzhi-6) using in vitro radioligand receptor binding assays and in vivo behavioral tests. Yuanzhi-1, -3, -5 and -6 were shown to have antidepressant-like activity in the tail suspension test and forced swim test in mice, with no stimulant effect on locomotor activity. The minimal effective dose of Yuanzhi-1 (2.5 mg/kg) was lower than that of duloxetine (5mg/kg), a serotonin and norepinephrine reuptake inhibitor commonly used in the treatment of depression. Yuanzhi-1 (1 nM) had a high affinity for serotonin, norepinephrine and dopamine transporters. Acute toxicity tests indicated that the LD50 of Yuanzhi-1 (86.5mg/kg) was similar to that of duloxetine (73.2 mg/kg). These findings demonstrate that Yuanzhi-1 has a potential to be a novel triple monoamine reuptake inhibitor of antidepressant-like activity.

Comparison of Two Old Phytochemicals versus Two Newly Researched Plant-Derived Compounds: Potential for Brain and Other Relevant Ailments

Among hundreds of formulae of Chinese herbal prescriptions and recently extracted active components from the herbs, some of which had demonstrated their functions on nervous system. For the last decade or more, Gingko biloba and Polygala tenuifolia were widely studied for their beneficial effects against damage to the brain. Two compounds extracted from Apium graveolens and Rhizoma coptidis, butylphthalide and berberine, respectively, received much attention recently as potential neuroprotective agents. In this review, the two traditionally used herbs and the two relatively new compounds will be discussed with regard to their potential advantages in alleviating brain and other relevant ailments.

Protective effect of senegenin on splenectomy-induced postoperative cognitive dysfunction in elderly rats

Postoperative cognitive dysfunction (POCD) is common in elderly patients. Senegenin, an active component of extracts from Polygala tenuifolia root, a traditional Chinese medicine, has neuroprotective and neuroregenerative effects. However, the mechanism underlying the effects of senegenin against postoperative cognitive impairment in elderly individuals has yet to be elucidated. The aim of this study was to investigate the protective effects of senegenin on the cognitive functions of elderly rats with splenectomy-induced POCD. Results from a Morris water maze test suggested that splenectomy induced a transient cognitive deficiency in the elderly rats; however, when the rats were treated with senegenin, the cognitive impairment was notably attenuated. Further experiments showed that senegenin significantly inhibited the mRNA and protein expression of several key pro-inflammatory cytokines, specifically, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-8, in the hippocampal tissues of elderly rats following splenectomy. In order to investigate the molecular mechanism involved, the expression and activity of the Toll-like receptor 4 (TLR4) signaling pathway was assessed. On day 1 postoperatively, it was observed that senegenin markedly suppressed the mRNA and protein expression of TLR4, myeloid differentiation factor 88 (MyD88) and TIR domain-containing adaptor-inducing interferon-β (TRIF). Furthermore, the phosphorylation levels of nuclear factor-κB (NF-κB) p65 and inhibitor of NF-κB (IκBα) were also decreased following senegenin treatment on the first day subsequent to surgery. These results suggest that senegenin suppressed splenectomy-induced transient cognitive impairment in elderly rats, possibly by downregulating two signaling pathways involved in inflammation, TLR4/MyD88/NF-κB and TLR4/TRIF/NF-κB, to further inhibit the expression of key pro-inflammatory cytokines, specifically, TNF-α, IL-1β, IL-6 and IL-8, and ultimately the neuroinflammation in the hippocampal tissues. In conclusion, the present study revealed that senegenin exhibited neuroprotective effects against splenectomy-induced transient cognitive impairment in elderly rats, which indicated that senegenin may be a promising agent for the treatment of POCD.

Memory-Enhancing Effects of the Crude Extract of Polygala tenuifolia on Aged Mice

Learning and memory disorders arise from distinct age-associated processes, and aging animals are often used as a model of memory impairment. The root of Polygala tenuifolia has been commonly used in some Asian countries as memory enhancer and its memory improvement has been reported in various animal models. However, there is less research to verify its effect on memory functions in aged animals. Herein, the memory-enhancing effects of the crude extract of Polygala tenuifolia (EPT) on normal aged mice were assessed by Morris water maze (MWM) and step-down passive avoidance tests. In MWM tests, the impaired spatial memory of the aged mice was partly reversed by EPT (100 and 200 mg/kg; P < 0.05) as compared with the aged control mice. In step-down tests, the nonspatial memory of the aged mice was improved by EPT (100 and 200 mg/kg; P < 0.05). Additionally, EPT could increase superoxide dismutase (SOD) and catalase (CAT) activities, inhibit monoamine oxidase (MAO) and acetyl cholinesterase (AChE) activities, and decrease the levels of malondialdehyde (MDA) in the brain tissue of the aged mice. The results showed that EPT improved memory functions of the aged mice probably via its antioxidant properties and via decreasing the activities of MAO and AChE.

Traditional Korean East Asian medicines and herbal formulations for cognitive impairment

Hanbang, the Traditional Korean Medicine (TKM), is an inseparable component of Korean culture both within the country, and further afield. Korean traditional herbs have been used medicinally to treat sickness and injury for thousands of years. Oriental medicine reflects our ancestor’s wisdom and experience, and as the elderly population in Korea is rapidly increasing, so is the importance of their health problems. The proportion of the population who are over 65 years of age is expected to increase to 24.3% by 2031. Cognitive impairment is common with increasing age, and efforts are made to retain and restore the cognition ability of the elderly. Herbal materials have been considered for this purpose because of their low adverse effects and their cognitive-enhancing or anti-dementia activities. Herbal materials are reported to contain several active compounds that have effects on cognitive function. Here, we enumerate evidence linking TKMs which have shown benefits in memory improvements. Moreover, we have also listed Korean herbal formulations which have been the subject of scientific reports relating to memory improvement.

Determination of fructooligosaccharides in burdock using HPLC and microwave-assisted extraction

The root of burdock ( Arctium lappa L.) is a commonly used vegetable in Asia. Fructooligosaccharides (FOS) are usually considered as its main bioactive components. Thus, quantitative analysis of these components is very important for the quality control of burdock. In this study, an HPLC-ELSD and microwave-assisted extraction method was developed for the simultaneous determination of seven FOS with degrees of polymerization (DP) between 3 and 9, as well as fructose, glucose, and sucrose in burdock from different regions. The separation was performed on a Waters XBridge Amide column (4.6 × 250 mm i.d., 3.5 μm) with gradient elution. All calibration curves for investigated analytes showed good linear regression (r > 0.9990). Their LODs and LOQs were lower than 3.63 and 24.82 μg/mL, respectively. The recoveries ranged from 99.2 to 102.6%. The developed method was successfully applied to determination of ten sugars in burdock from different locations of Asia. The results showed that the contents of FOS in different samples of burdock collected at appropriate times were similar, and the developed HPLC-ELSD with microwave-assisted extraction method is helpful to control the quality of burdock.

Tenuigenin treatment improves behavioral Y-maze learning by enhancing synaptic plasticity in mice

Polygala tenuifolia root has been used to improve memory and cognitive function in Traditional Chinese Medicine for more than 2000 years. Since tenuigenin (TEN) is one of the most utilized P. tenuifolia root extracts, it is surprising there is no evidence for the effects of TEN on learning and memory so far. In the present study, we investigated the effects of TEN on learning and memory with Y-maze test in mice. We found that oral administration of 4mg/kg TEN significantly improved learning and memory in Y-maze task. Treatment with 4mg/kg TEN markedly reduced the acetylcholinesterase (AChE) activity and malondialdehyde (MDA) level, and increased superoxide dismutase (SOD) activity in hippocampus. In the electrophysiological test of hippocampal brain slice, 2μg/ml TEN perfusion substantially enhanced field excitatory postsynaptic potential (fEPSP) amplitude both in basic synaptic transmission and after high frequency stimulation (HFS) in Schaffer to CA1 pathway (Scha-CA1). These results indicate that TEN enhancing learning and memory may result from inhibiting AChE activity, improving antioxidation and enhancing synaptic plasticity in mice. Therefore, TEN shows promise as a potential nootropic product in improving learning and memory.

Senegenin attenuates hepatic ischemia-reperfusion induced cognitive dysfunction by increasing hippocampal NR2B expression in rats

Background

The root of Polygala tenuifolia, a traditional Chinese medicine, has been used to improve memory and intelligence, while the underlying mechanisms remain largely unknown. In this study, we investigated the protective effects of senegenin, an component of Polygala tenuifolia root extracts, on cognitive dysfunction induced by hepatic ischemia-reperfusion.

Methodology/Principal Findings

Initially, we constructed a rat model of hepatic ischemia-reperfusion (HIR) and found that the memory retention ability of rats in the step-down and Y maze test was impaired after HIR, paralleled by a decrease of N-methyl-D-aspartate (NMDA) receptor NR2B subunit mRNA and protein expressions in hippocampus. Furthermore, we found that administration of senegenin by gavage attenuated HIR-induced cognitive impairment in a dose and time dependent manner, and its mechanisms might partly due to the increasing expression of NR2B in rat hippocampus.

Conclusions/Significance

Cognitive dysfunction induced by HIR is associated with reduction of NR2B expression. Senegenin plays a neuroprotective role in HIR via increasing NR2B expression in rat hippocampus. These findings suggest that senegenin might be a potential agent for prevention and treatment of postoperative cognitive dysfunction (POCD) or other neurodegenerative diseases.