Polysaccharide of Schisandra Chinensis Fructus ameliorates cognitive decline in a mouse model of Alzheimer's disease

Structural characterization of a galactoglucomannan with anti-neuroinflammatory activity from Ganoderma lucidum

According to traditional Chinese medicine theory, Ganoderma lucidum (G. lucidum) presents certain effects for nourishing nerves and calming the mind. G. lucidum polysaccharides (GLPs) have various biological activities; however, the structural characterization and the structure-activity relationship in anti-neuroinflammation of GLPs needs to be further investigated. In this work, the crude polysaccharide GL70 exhibited a remarkable impact on enhancing the spatial learning and memory function, as well as reducing the anxiety symptoms of the lipopolysaccharide (LPS)-induced rat model of Alzheimer's disease (AD). A galactoglucomannan (GLP70-1-2) was isolated from GL70, and characterized by monosaccharide composition, partial acid hydrolysis, methylation, and NMR analysis. The backbone of GLP70-1-2 was →6)-α-D-glcp-(1 → 6)-β-D-galp-(1 → [6)-β-D-manp-(1]3 → 4)-α-D-Glcp-(1 → 6)-α-D-glcp-(1 → 2)-β-D-galp-(1 → [4)-α-D-glcp-(1 → 6)-β-D-manp-(1 → 2)-β-D-galp-(1]2 → 6)-β-D-glcp-(1 → 6)-β-D-glcp-(1→ with two side chains attached to O-4 of →6)-β-D-galp-(1→ and O-3 of →6)-β-D-glcp-(1→, respectively. In addition, GLP70-1-2 exhibited remarkable efficacy in decreasing the level of pro-inflammatory factors in LPS-activated BV2 cells through the TLR4/MyD88/NF-κB pathway. Collectively, GLP70-1-2 exhibited significant anti-neuroinflammatory activity and may have the potential for developing as a drug for AD.

Gegen Qinlian tablets delay Alzheimer's disease progression via inhibiting glial neuroinflammation and remodeling gut microbiota homeostasis

BACKGROUND

Current therapeutic agents for AD have limited efficacy and often induce undesirable side effects. Gegen Qinlian tablets (GGQLT) are a well-known clearingheat formula used in clinical treatment of inflammatory diseases. Based on traditional Chinese medicine (TCM) theory, the strategy of clearing-heat is then compatible with the treatment of AD. However, it remains unknown whether GGQLT can exert neuroprotective effects and alleviate neuroinflammation in AD.

PURPOSE

This study aimed to evaluate the anti-AD effects of GGQLT and to decipher its intricate mechanism using integrative analyses of network pharmacology, transcriptomic RNA sequencing, and gut microbiota.

METHODS

The ingredients of GGQLT were analyzed using HPLC-ESI-Q/TOF-MS. The AD model was established by bilateral injection of Aβ1-42 into the intracerebroventricular space of rats. The Morris water maze was used to evaluate the cognitive function of the AD rats. The long-term toxicity of GGQLT in rats was assessed by monitoring their body weights and pathological alterations in the liver and kidney. Reactive astrocytes and microglia were assessed by immunohistochemistry by labeling GFAP and Iba-1. The levels of inflammatory cytokines in the hippocampus were evaluated using ELISA kits, RT-PCR, and Western blot, respectively. The potential anti-AD mechanism was predicted by analyses of RNA-sequencing and network pharmacology. Western blot and immunohistochemistry were utilized to detect the phosphorylation levels of IκBα, NF-κB p65, p38, ERK and JNK. The richness and composition of gut bacterial and fungal microflora were investigated via 16S rRNA and ITS sequencing.

RESULTS

Typical ingredients of GGQLT were identified using HPLC-ESI-Q/TOF-MS. GGQLT significantly improved the cognitive function of AD rats by suppressing the activation of microglia and astrocytes, improving glial morphology, and reducing the neuroinflammatory reactions in the hippocampus. RNA-sequencing, network and experimental pharmacological studies demonstrated that GGQLT inhibited the activation of NF-κB/MAPK signaling pathways in the hippocampus. GGQLT could also restore abnormal gut bacterial and fungal homeostasis and no longer-term toxicity of GGQLT was observed.

CONCLUSIONS

Our findings, for the first time, demonstrate GGQLT exhibit anti-AD effects and is worthy of further exploration and development.

Extraction, purification, structural characterization, and biological activity of polysaccharides from Schisandra chinensis: A review

Schisandra chinensis (SC), a plant of the Magnoliaceae family, commonly known as "North Schisandra chinensis", has been listed as a top-grade Chinese medicine in the Shennong Materia Medica Classic for its high medicinal value since ancient times. Polysaccharides from S. chinensis fruits (SCPs) are an active component in SC, which have various biological activity, including immune regulation, anti-tumor, antioxidant, liver protective, anti-inflammatory and hypoglycemic activity. Research has shown that the extraction methods of SCPs include hot water extraction, water extraction and alcohol precipitation, ultrasonic-assisted, microwave-assisted and so on. Different extraction methods can affect the yield and purity of polysaccharides, and to improve the extraction yield of SCPs, two or more extraction methods can be combined. SCPs are mainly composed of glucose, mannose, rhamnose, galactose, galacturonic acid and arabinose. This article aims to provide a systematic review of the research progress in the extraction and separation methods, structural characterization, and biological activity of SCPs both domestically and internationally in recent years. This deeply explores the pharmacological activity and action mechanism of SCPs, and provides a certain point of reference for the research and clinical application of SC.

Targeting chemokine-receptor mediated molecular signaling by ethnopharmacological approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Infection and inflammation are critical to global human health status and the goal of current pharmacological interventions intends formulating medications/preventives as a measure to deal with this situation. Chemokines and their cognate receptors are major regulatory molecules in many of these ailments. Natural products have been a keen source to the drug development industry, every year contributing significantly to the growing list of FDA approved drugs. A multiverse of natural resource is employed as a part of curative regimen in folk/traditional/ethnomedicine which can be employed to discover, repurpose, and design potent medications for the diseases of clinical concern.

AIM OF THE STUDY

This review aims to systematically document the ethnopharmacologically active agents targeting the infectious-inflammatory diseases through the chemokine-receptor nexus.

MATERIALS AND METHODS

Articles related to chemokine/receptor modulating ethnopharmacological anti-inflammatory, anti-infectious natural sources, bioactive compounds, and formulations have been examined with special emphasis on women related diseases. The available literature has been thoroughly scrutinized for the application of traditional medicines in chemokine associated experimental methods, their regulatory outcomes, and pertinence to women's health wherever applicable. Moreover, the potential traditional regimens under clinical trials have been critically assessed.

RESULTS

A systematic and comprehensive review on the chemokine-receptor targeting ethnopharmaceutics from the available literature has been provided. The article discusses the implication of traditional medicine in the chemokine system dynamics in diverse infectious-inflammatory disorders such as cardiovascular diseases, allergic diseases, inflammatory diseases, neuroinflammation, and cancer. On this note, critical evaluation of the available data surfaced multiple diseases prevalent in women such as osteoporosis, rheumatoid arthritis, breast cancer, cervical cancer and urinary tract infection. Currently there is no available literature highlighting chemokine-receptor targeting using traditional medicinal approach from women's health perspective. Moreover, despite being potent in vitro and in vivo setups there remains a gap in clinical translation of these formulations, which needs to be strategically and scientifically addressed to pave the way for their successful industrial translation.

CONCLUSIONS

The review provides an optimistic global perspective towards the applicability of ethnopharmacology in chemokine-receptor regulated infectious and inflammatory diseases with special emphasis on ailments prevalent in women, consecutively addressing their current status of clinical translation and future directions.

Structural identification and anti-neuroinflammatory effect of a heteropolysaccharide ATP50-3 from Acorus tatarinowii rhizome

Acorus tatarinowii, a famous traditional Chinese medicine, is used for the clinical treatment of memory impairment and dementia. In this research, AT50, the crude polysaccharide extracted from A. tatarinowii rhizome, significantly improved the memory and learning ability of mice with Alzheimer's disease (AD) and exerted excellent anti-neuroinflammatory effects. More importantly, AT50 returned the levels of NO, TNF-α, IL-1β, PGE-2, and IL-6 in AD mouse brains to normal levels. To identify the active ingredients in AT50, a heteropolysaccharide ATP50-3 was obtained from AT50. Structural analysis indicated ATP50-3 consisted of α-L-Araf-(1→, →2)-α-L-Araf-(1→, →3)-α-L-Araf-(1→, →5)-α-L-Araf-(1→, α-D-Xylp-(1→, →3,4)-β-D-Xylp-(1→, →3)-α-D-Galp-(1→, →3,6)-α-D-Galp-(1→, →6)-4-OAc-α-D-Galp-(1→, →3,4,6)-α-D-Galp-(1→, →4)-α-D-Glcp-(1→, →2,3,6)-β-D-Glcp-(1→, →4,6)-α-D-Manp-(1→, →3,4)-α-L-Rhap-(1→, →4)-α-D-GalpA-(1→, and →4)-α-D-GlcpA-(1 → residues and terminated with Xyl and Ara. Additionally, ATP50-3 significantly inhibited the release of proinflammatory factors in lipopolysaccharide-stimulated BV2 cells. ATP50-3 may be an active constituent of AT50, responsible for its anti-neuroinflammatory effects, with great potential to treat AD.

Along the microbiota-gut-brain axis: Use of plant polysaccharides to improve mental disorders

With the development of gut microbiota-specific interventions for mental disorders, the interactions between plant polysaccharides and microbiota in the intestinal and their consequent effects are becoming increasingly important. In this review, we discussed the role of plant polysaccharides in improving various mental disorders via the microbiota-gut-brain axis. The chemical and structural characteristics and metabolites of these plant polysaccharides were summarised. Plant polysaccharides and their metabolites have great potential for reshaping gut microbiota profiles through gut microbiota-dependent fermentation. Along the microbiota-gut-brain axis, the consequent pharmacological processes that lead to the elimination of the symptoms of mental disorders include 1) regulation of the central monoamine neurotransmitters, amino acid transmitters and cholinergic signalling system; 2) alleviation of central and peripheral inflammation mainly through the NLRP3/NF-κB-related signalling pathway; 3) inhibition of neuronal apoptosis; and 4) enhancement of antioxidant activities. According to this review, monosaccharide glucose and structure -4-α-Glcp-(1→ are the most potent compositions of the most reported plant polysaccharides. However, the causal structure-activity relationship remains to be extensively explored. Moreover, mechanistic elucidation, safety verification, and additional rigorous human studies are expected to advance plant polysaccharide-based product development targeting the microbiota-gut-brain axis for people with mental disorders.

Research progress in the preparation, structural characterization, and biological activities of polysaccharides from traditional Chinese medicine

Traditional Chinese medicines are tremendous sources of polysaccharides, which are of great interest in the human welfare system as natural medicines, food, and cosmetics. This review aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of traditional Chinese medicine polysaccharides (TCMPs), and the chemical structure, biological activities (anti-tumor, hypoglycemic, antioxidant, intestinal flora regulation, immunomodulatory, anti-inflammatory, anti-aging, hypolipidemic, hepatoprotective, and other activities), and the underlying mechanisms of polysaccharides extracted from 76 diverse traditional Chinese medicines were compared and discussed. With this wide coverage, a total of 164 scientific articles were searched from the database including Google Scholar, PubMed, Web of Science, and China Knowledge Network. This comprehensive survey from previous reports indicates that TCMPs are non-toxic, highly biocompatible, and good biodegradability. Besides, this review highlights that TCMPs may be excellent functional factors and effective therapeutic drugs. Finally, the current problems and future research advances of TCMPs are also introduced. New valuable insights for the future researches regarding TCMPs are also proposed in the fields of therapeutic agents and functional foods.

The extraction, purification, structural features, bioactivities, and applications of Schisandra chinensis polysaccharides: A review

Schisandra chinensis, as a famous medicinal and food homologous plant, has a long history of medicinal and dietary therapy. It has the functions of nourishing the kidney, calming the heart, tranquilising the mind, tonifying Qi and producing fluid to relieve mental stress, based on the theory of traditional Chinese medicine. Accumulating evidence has shown that S. chinensis polysaccharides (SCPs) are one of the most important bioactive macromolecules and exhibit diverse biological activities in vitro and in vivo, including neuroprotective, hepatoprotective, immunomodulatory, antioxidant, hypoglycemic, cardioprotective, antitumour and anti-inflammatory activities, etc. This review aims to thoroughly review the recent advances in the extraction and purification methods, structural features, biological activities and structure-activity relationships, potential applications and quality assessment of SCPs, and further highlight the therapeutic potentials and health functions of SCPs in the fields of therapeutic agents and functional food development. Future insights and challenges of SCPs were also critically discussed. Overall, the present review provides a theoretical overview for the further development and utilization of S. chinensis polysaccharides in the health food and pharmaceutical fields.

Extraction, purification, structural characterization, and bioactivities of the genus Schisandra polysaccharides: A review

The genus Schisandra, a member of the Magnoliaceae family, is a well-known tonic traditional Chinese medicine with a long history of traditional medicinal and functional food used in China. Polysaccharides are one of its main active constituents, which have a wide range of bioactivities, such as anti-inflammatory, anti-tumor, neuroprotection, anti-diabetes, hepatoprotection, immunomodulation, and anti-fatigue. In this paper, we review the extraction, isolation, purification, structural characterization, bioactivities, as well as structure-activity relationship of polysaccharides from the genus Schisandra. In conclusion, we hope that this review could provide reference for the subsequent research on structural, bioactivities, development and application of the genus Schisandra polysaccharides.

Rapid Discovery of Aβ42 Fibril Disintegrators from Ganoderma lucidum via Ligand Fishing and Their Neuroprotective Effects on Alzheimer's Disease

An amyloid-β (Aβ) fibril is a vital pathogenic factor of Alzheimer's disease (AD). Aβ fibril disintegrators possess great potential to be developed into novel anti-AD agents. Here, a ligand fishing method was employed to rapidly discover Aβ42 fibril disintegrators from Ganoderma lucidum using Aβ42 fibril-immobilized magnetic beads, which led to the isolation of six Aβ42 fibril disintegrators including ganodermanontriol, ganoderic acid DM, ganoderiol F, ganoderol B, ganodermenonol, and ergosterol. Neuroprotective evaluation in vitro exhibited that these Aβ42 fibril disintegrators could significantly mitigate Aβ42-induced neurotoxicity. Among these six disintegrators, ergosterol and ganoderic acid DM with stronger protecting activity were further selected to evaluate their neuroprotective effect on AD in vivo. Results showed that ergosterol and ganoderic acid DM could significantly alleviate Aβ42-induced cognitive dysfunction and hippocampus neuron loss in vivo. Moreover, ergosterol and ganoderic acid DM could significantly inhibit Aβ42-induced neuron apoptosis and Nrf2-mediated neuron oxidative stress in vitro and in vivo.

The molecular mechanism of polysaccharides in combating major depressive disorder: A comprehensive review

Major depressive disorder (MDD) is a complex psychiatric condition with diverse etiological factors. Typical pathological features include decreased cerebral cortex, subcortical structures, and grey matter volumes, as well as monoamine transmitter dysregulation. Although medications exist to treat MDD, unmet needs persist due to limited efficacy, induced side effects, and relapse upon drug withdrawal. Polysaccharides offer promising new therapies for MDD, demonstrating antidepressant effects with minimal side effects and multiple targets. These include neurotransmitter, neurotrophin, neuroinflammation, hypothalamic-pituitary-adrenal axis, mitochondrial function, oxidative stress, and intestinal flora regulation. This review explores the latest advancements in understanding the pharmacological actions and mechanisms of polysaccharides in treating major depression. We discuss the impact of polysaccharides' diverse structures and properties on their pharmacological actions, aiming to inspire new research directions and facilitate the discovery of novel anti-depressive drugs.

Mechanisms and structure-activity relationships of polysaccharides in the intervention of Alzheimer's disease: A review

Alzheimer's disease (AD) is a complex neurodegenerative disease. Despite several decades of research, the development of effective treatments and responses for Alzheimer's disease remains elusive. The utilization of polysaccharides for Alzheimer's disease became more popular due to their beneficial characteristics, notably their multi-target activity and low toxicity. This review mainly focuses on the researches of recent 5 years in the regulation of AD by naturally derived polysaccharides, systematically lists the possible intervention pathways of polysaccharides from different mechanisms, and explores the structure-activity relationship between polysaccharide structural activities, so as to provide references for the intervention and treatment of AD by polysaccharides.

Isolinderalactone Ameliorates the Pathology of Alzheimer's Disease by Inhibiting the JNK Signaling Pathway

Neuronal cell damage is a major cause of cognitive impairment in Alzheimer's disease (AD). Multiple factors, such as amyloid deposition, tau hyperphosphorylation, and neuroinflammation, can lead to neuronal cell damage. Therefore, the development of multi-target drugs with broad neuroprotective effects may be an effective strategy for the treatment of AD. Natural products have become an important source of drug discovery because of their good pharmacological activity, multiple targets, and low toxicity. In this study, we screened a natural compound library and found that the fat-soluble sesquiterpene natural compound isolinderalactone (Iso) extracted from the dried root pieces of Lindera aggregata had the ability to alleviate cellular damage induced by β-amyloid-1-42 (Aβ1-42). The role and mechanism of Iso in AD have not yet been reported. Herein, we demonstrated that Iso significantly reduced the level of apoptosis in PC12 cells. Besides, Iso treatment reduced amyloid deposition, neuron apoptosis, and neuroinflammation, ultimately improving the cognitive dysfunction of APP/PS1 (APPswe/PSEN 1dE9) mice. Notably, Iso-10 mg/kg showed superior improved effects in APP/PS1 mice compared with the positive control drug donepezil-5 mg/kg. Mechanistically, the results of RNA sequencing combined with Western blots showed that Iso exerted its therapeutic effect by inhibiting the c-Jun N-terminal kinase (JNK) signaling pathway. Taken together, our findings suggest that Iso is a potential drug candidate for the treatment of AD.

Unveiling the neuroprotective potential of dietary polysaccharides: a systematic review

Central nervous system (CNS) disorders present a growing and costly global health challenge, accounting for over 11% of the diseases burden in high-income countries. Despite current treatments, patients often experience persistent symptoms that significantly affect their quality of life. Dietary polysaccharides have garnered attention for their potential as interventions for CNS disorders due to their diverse mechanisms of action, including antioxidant, anti-inflammatory, and neuroprotective effects. Through an analysis of research articles published between January 5, 2013 and August 30, 2023, encompassing the intervention effects of dietary polysaccharides on Alzheimer's disease, Parkinson's disease, depression, anxiety disorders, autism spectrum disorder, epilepsy, and stroke, we have conducted a comprehensive review with the aim of elucidating the role and mechanisms of dietary polysaccharides in various CNS diseases, spanning neurodegenerative, psychiatric, neurodevelopmental disorders, and neurological dysfunctions. At least four categories of mechanistic bases are included in the dietary polysaccharides' intervention against CNS disease, which involves oxidative stress reduction, neuronal production, metabolic regulation, and gut barrier integrity. Notably, the ability of dietary polysaccharides to resist oxidation and modulate gut microbiota not only helps to curb the development of these diseases at an early stage, but also holds promise for the development of novel therapeutic agents for CNS diseases. In conclusion, this comprehensive review strives to advance therapeutic strategies for CNS disorders by elucidating the potential of dietary polysaccharides and advocating interdisciplinary collaboration to propel further research in this realm.

Schisandrin B Protects against Ischemic Brain Damage by Regulating PI3K/AKT Signaling in Rats

OBJECTIVE

To explore the effect and mechanism of schisandrin B (Sch B) in the treatment of cerebral ischemia in rats.

METHODS

The cerebral ischemia models were induced by middle cerebral artery occlusion (MCAO) and reperfusion. Sprague-Dawley rats were divided into 6 groups using a random number table, including sham, MCAO, MCAO+Sch B (50 mg/kg), MCAO+Sch B (100 mg/kg), MCAO+Sch B (100 mg/kg)+LY294002, and MCAO+Sch B (100 mg/kg)+wortmannin groups. The effects of Sch B on pathological indicators, including neurological deficit scores, cerebral infarct volume, and brain edema, were subsequently studied. Tissue apoptosis was identified by terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining. The protein expressions involved in apoptosis, inflammation response and oxidative stress were examined by immunofluorescent staining, biochemical analysis and Western blot analysis, respectively. The effect of Sch B on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling was also explored.

RESULTS

Sch B treatment decreased neurological deficit scores, cerebral water content, and infarct volume in MCAO rats (P<0.05 or P<0.01). Neuronal nuclei and TUNEL staining indicated that Sch B also reduced apoptosis in brain tissues, as well as the Bax/Bcl-2 ratio and caspase-3 expression (P<0.01). Sch B regulated the production of myeloperoxidase, malondialdehyde, nitric oxide and superoxide dismutase, as well as the release of cytokine interleukin (IL)-1 β and IL-18, in MCAO rats (P<0.05 or P<0.01). Sch B promoted the phosphorylation of PI3K and AKT. Blocking the PI3K/AKT signaling pathway with LY294002 or wortmannin reduced the protective effect of Sch B against cerebral ischemia (P<0.05 or P<0.01).

CONCLUSIONS

Sch B reduced apoptosis, inflammatory response, and oxidative stress of MCAO rats by modulating the PI3K/AKT pathway. Sch B had a potential for treating cerebral ischemia.

Polysaccharides: potential bioactive macromolecules for Alzheimer's disease

Alzheimer's disease (AD) is one of the leading causes of death and disability. AD is a devastating disease that has caused an overwhelming burden. However, no disease-modified treatment was discovered. The approval of sodium oligomannate (GV-971) in mild-moderate AD patients has attracted great attention to investigate the role of saccharides in AD. Therefore, summarizing and explaining the role of saccharides in AD is urgent and promising. Recent studies showed that polysaccharides (PSs) potentially benefit AD in vitro and in vivo. PSs could alleviate the pathological damage and improve cognitive symptoms via (1) antagonizing the toxicity of abnormal amyloid-beta and tau proteins; (2) attenuating oxidative stress and proinflammation; (3) rebuilding neuroplasticity. PSs exhibit one-multiple pathological hits of AD. However, a thorough chemical investigation is needed for further study.

In Silico Analysis, Anticonvulsant Activity, and Toxicity Evaluation of Schisandrin B in Zebrafish Larvae and Mice

The aim of this study is to evaluate the anticonvulsant potential of schisandrin B, a main ingredient of Schisandra chinensis extracts. Schisandrin B showed anticonvulsant activity in the zebrafish larva pentylenetetrazole acute seizure assay but did not alter seizure thresholds in the intravenous pentylenetetrazole test in mice. Schisandrin B crosses the blood-brain barrier, which we confirmed in our in silico and in vivo analyses; however, the low level of its unbound fraction in the mouse brain tissue may explain the observed lack of anticonvulsant activity. Molecular docking revealed that the anticonvulsant activity of the compound in larval zebrafish might have been due to its binding to a benzodiazepine site within the GABAA receptor and/or the inhibition of the glutamate NMDA receptor. Although schisandrin B showed a beneficial anticonvulsant effect, toxicological studies revealed that it caused serious developmental impairment in zebrafish larvae, underscoring its teratogenic properties. Further detailed studies are needed to precisely identify the properties, pharmacological effects, and safety of schisandrin B.

An analysis of the nutritional effects of Schisandra chinensis components based on mass spectrometry technology

OBJECTIVE

Schisandra chinensis (Turcz.) Baill. (S. chinensis) is a Traditional Chinese medicinal herb that can be used both for medicinal purposes and as a food ingredient due to its beneficial properties, and it is enriched with a wide of natural plant nutrients, including flavonoids, phenolic acids, anthocyanins, lignans, triterpenes, organic acids, and sugars. At present, there is lack of comprehensive study or systemic characterization of nutritional and active ingredients of S. chinensis using innovative mass spectrometry techniques.

METHODS

The comprehensive review was conducted by searching the PubMed databases for relevant literature of various mass spectrometry techniques employed in the analysis of nutritional components in S. chinensis, as well as their main nutritional effects. The literature search covered the past 5 years until March 15, 2023.

RESULTS

The potential nutritional effects of S. chinensis are discussed, including its ability to enhance immunity, function as an antioxidant, anti-allergen, antidepressant, and anti-anxiety agent, as well as its ability to act as a sedative-hypnotic and improve memory, cognitive function, and metabolic imbalances. Meanwhile, the use of advanced mass spectrometry detection technologies have the potential to enable the discovery of new nutritional components of S. chinensis, and to verify the effects of different extraction methods on these components. The contents of anthocyanins, lignans, organic acids, and polysaccharides, the main nutritional components in S. chinensis, are also closely associated to its quality.

CONCLUSION

This review will provide guidelines for an in-depth study on the nutritional value of S. chinensis and for the development of healthy food products with effective components.

The Potential of Edible and Medicinal Resource Polysaccharides for Prevention and Treatment of Neurodegenerative Diseases

As natural medicines in complementary and alternative medicine, edible and medicinal resources are being gradually recognized throughout the world. According to statistics from the World Health Organization, about 80% of the worldwide population has used edible and medicinal resource products to prevent and treat diseases. Polysaccharides, one of the main effective components in edible and medicinal resources, are considered ideal regulators of various biological responses due to their high effectiveness and low toxicity, and they have a wide range of possible applications for the development of functional foods for the regulation of common, frequently occurring, chronic and severe diseases. Such applications include the development of polysaccharide products for the prevention and treatment of neurodegenerative diseases that are difficult to control by a single treatment, which is of great value to the aging population. Therefore, we evaluated the potential of polysaccharides to prevent neurodegeneration by their regulation of behavioral and major pathologies, including abnormal protein aggregation and neuronal damage caused by neuronal apoptosis, autophagy, oxidative damage, neuroinflammation, unbalanced neurotransmitters, and poor synaptic plasticity. This includes multi-target and multi-pathway regulation involving the mitochondrial pathway, MAPK pathway, NF-κB pathway, Nrf2 pathway, mTOR pathway, PI3K/AKT pathway, P53/P21 pathway, and BDNF/TrkB/CREB pathway. In this paper, research into edible and medicinal resource polysaccharides for neurodegenerative diseases was reviewed in order to provide a basis for the development and application of polysaccharide health products and promote the recognition of functional products of edible and medicinal resources.

Advances in Plant Polysaccharides as Antiaging Agents: Effects and Signaling Mechanisms

Aging refers to the gradual physiological changes that occur in an organism after reaching adulthood, resulting in senescence and a decline in biological functions, ultimately leading to death. Epidemiological evidence shows that aging is a driving factor in the developing of various diseases, including cardiovascular diseases, neurodegenerative diseases, immune system disorders, cancer, and chronic low-grade inflammation. Natural plant polysaccharides have emerged as crucial food components in delaying the aging process. Therefore, it is essential to continuously investigate plant polysaccharides as potential sources of new pharmaceuticals for aging. Modern pharmacological research indicates that plant polysaccharides can exert antiaging effects by scavenging free radicals, increasing telomerase activity, regulating apoptosis, enhancing immunity, inhibiting glycosylation, improving mitochondrial dysfunction regulating gene expression, activating autophagy, and modulating gut microbiota. Moreover, the antiaging activity of plant polysaccharides is mediated by one or more signaling pathways, including IIS, mTOR, Nrf2, NF-κB, Sirtuin, p53, MAPK, and UPR signaling pathways. This review summarizes the antiaging properties of plant polysaccharides and signaling pathways participating in the polysaccharide-regulating aging process. Finally, we discuss the structure-activity relationships of antiaging polysaccharides.

In-depth investigation of the mechanisms of Schisandra chinensis polysaccharide mitigating Alzheimer's disease rat via gut microbiota and feces metabolomics

Schisandra chinensis (S. chinensis) is an herbal medicine used for the treatment of Alzheimer's disease (AD). The purified polysaccharide fraction, namely SCP2, was previously isolated from S. chinensis crude polysaccharide (SCP) and its structure and in vitro activity were investigated. However, the in vivo activity of SCP2 and its potential mechanism for the treatment of AD have yet to be determined. This study used a combination of microbiomics and metabolomics to comprehensively explore the microbiota and metabolic changes in AD rats under SCP2 intervention, with the aim of elucidating the potential mechanisms of SCP2 in the treatment of AD. SCP2 showed significant therapeutic effects in AD rats, as evidenced by improved learning and memory capacity, reduced neuroinflammation, and restoration of the integrity of the intestinal barrier. Fecal metabolomic and microbiomic analyses revealed that SCP2 significantly modulated 19 endogenous metabolites and reversed gut microbiota disorders in AD rats. Moreover, SCP2 significantly increased the content of short-chain fatty acid (SCFAs) in the AD rats. Correlation analysis showed a significant correlation between gut microbes, metabolites and the content of SCFAs. Collectively, these findings will provide the basis for further development of SCP2.

An alternative strategy based on ultra-high-performance supercritical fluid chromatography for full monosaccharide compositional analysis of polysaccharides in Schisandra chinensis fruits

Due to green and environment-friendly characteristics, ultra-high-performance supercritical fluid chromatography has been widely used in analytical fields in recent years, but until now few reports are available for monosaccharide compositional analysis of macromolecule polysaccharides. In this study, an ultra-high-performance supercritical fluid chromatography technology with an unusual binary modifier is used to determine the monosaccharide compositions of natural polysaccharides. Each carbohydrate herein is simultaneously labeled as 1-pheny-3-methyl-5-pyrazolone and acetyl-derivative via pre-column derivatizations aiming to increase UV absorption sensitivity and decrease water solubility. Ten common monosaccharides are fully separated and detected on ultra-high-performance supercritical fluid chromatography combined with a photo-diode array detector by systematic optimization of multiple relevant parameters, for example, column stationary phases, organic modifiers, additives, flow rates, and so on. Compared with carbon dioxide as a mobile phase, the addition of a binary modifier increases the resolution of analytes. Additionally, this method has the advantages of small consumption of organic solvent, safety, and being environmental-friendly. It has been successfully applied for full monosaccharide compositional analysis of heteropolysaccharides from Schisandra chinensis fruits. To sum up, a new alternative approach is provided for monosaccharide compositional analysis of natural polysaccharides.

An integrated study on the comprehensive mechanism of Schisandra chinensis polysaccharides mitigating Alzheimer's disease in rats using a UPLC-Q-TOF-MS based serum and urine metabolomics strategy

As a well-known traditional Chinese medicine and functional food, Schisandra chinensis (S. chinensis) has been proved to possess excellent neuroprotective effects, and particularly the role of the polysaccharide fraction in neuroprotection has been increasingly emphasized. The aim of this study was to investigate the therapeutic effects and potential mechanism of action of the homogeneous polysaccharide SCP2, isolated and purified from S. chinensis polysaccharide (SCP), on Alzheimer's disease (AD) rats based on a holistic metabolomics approach in serum and urine. The results of the pharmacodynamics study showed that SCP2 significantly improved Aβ_25-35-induced cognitive dysfunction, improved oxidative damage and reduced Aβ deposition in the hippocampus. The holistic metabolomics results of serum and urine showed that the intervention with SCP2 significantly reversed the metabolic profile disorder in AD rats. A total of 40 metabolites (21 serum metabolites and 19 urine metabolites) were identified, which were mainly involved in linoleic acid metabolism, alpha-linolenic acid metabolism and arachidonic acid metabolism. The results obtained in this study will provide new insights into the mechanisms of SCP2 in the treatment of AD and provide a basis for the subsequent structure-activity studies of SCP2.

Kaempferol as a potential neuroprotector in Alzheimer's disease

Alzheimer's disease (AD), the most prevalent neurodegenerative disorder, is largely associated with cognitive disability, amnesia, and abnormal behavior, which accounts for about two third of people with dementia worldwide. A growing body of research demonstrates that AD is connected to several factors, such as aberrant accumulation of amyloid-beta (Aβ), increase in the hyperphosphorylation of Tau protein, and the formation of neurofibrillary tangles, mitochondrial dysfunction, and inordinate production of reactive oxygen species (ROS). Despite remarkable efforts to realize the etiology and pathophysiology of AD, until now, scientists have not developed and introduced medications that can permanently cease the progression of AD. Thus, nowadays, research on the role of natural products in the treatment and prevention of AD has attracted great attention. Kaempferol (KMP), one of the prominent members of flavonols, exerts its ameliorative actions via attenuating oxidative stress and inflammation, reducing Aβ-induced neurotoxicity, and regulating the cholinergic system. Therefore, in this review article, we outlined the possible effects of KMP in the prevention and treatment of AD. PRACTICAL APPLICATIONS: Kaempferol (KMP) exerts its ameliorative actions against AD via attenuating oxidative stress and inflammation, reducing Aβ-induced neurotoxicity, and regulating the cholinergic system. The beneficial effects of KMP were addressed in both in vitro and in vivo studies; however, conducting further research can warrant its long-term effects as a safe agent. Therefore, after confirming its favorable functions in the prevention and treatment of AD, it could be used as a safe and effective agent.

Schisandra chinensis Lignans Exert Antidepressant Effects by Promoting BV2 Microglia Polarization toward the M2 Phenotype through the Activation of the Cannabinoid Receptor Type-2-Signal Transducer and Activator of Transcription 6 Pathway

Based on the current results, they showed that Schisandra chinensis lignans (SCL) ameliorated depressive-like behaviors in chronic unpredictable mild stress (CUMS) mice, alleviated neuroinflammation, and improved neuronal injury. This study aimed to explore whether SCL exerted antidepressant effects through inhibiting neuroinflammation, in turn improving neuronal injury. In vitro studies revealed that SCL blocked lipopolysaccharide-increased BV2 microglial M1 but promoted the M2 phenotype. The BV2-N2a interaction model suggested that increasing the M2 phenotype of BV2 played neuroprotective effects. The current studies demonstrated that SCL up-regulated the expression of CUMS- and LPS-decreased cannabinoid receptor type-2 (CB2R) mRNA. In vitro studies showed that the transfection of BV2 with siCrn2 blocked the SCL-increased M2 phenotype via the inactivating signal transducer and activator of transcription 6 (STAT6) pathway, further decreasing the viability of N2a cells. Finally, the possible pharmacodynamic compounds, γ-schisandrin and schisantherin A, were indicated by AutoDuck analysis. Overall, our study showed that SCL promoted microglia polarization toward the M2 phenotype, in turn exerting neuroprotective effects by activating CB2R-STAT6 signaling further to play antidepressant roles.

Lacticaseibacillus rhamnosus-Derived Exopolysaccharide Attenuates D-Galactose-Induced Oxidative Stress and Inflammatory Brain Injury and Modulates Gut Microbiota in a Mouse Model

This study aimed to investigate the protective effect of a novel exopolysaccharide EPSRam12, produced by Lacticaseibacillus rhamnosus Ram12, against D-galactose-induced brain injury and gut microbiota dysbiosis in mice. The findings demonstrate that EPSRam12 increases the level of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, total antioxidant capacity, and the level of anti-inflammatory cytokine IL-10, while decreasing malonaldehyde, nitric oxide, pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, MCP-1, and the mRNA expression of cyclooxygenase-2, inducible nitric oxide synthase, and the activation of nuclear factor-kappa-B in the brain tissues of D-galactose-treated mice. Further analyses reveal that EPSRam12 improves gut mucosal barrier function and increases the levels of short-chain fatty acids (SCFAs) in the intestine while restoring gut microbial diversity by enriching the abundance of SCFA-producing microbial genera Prevotella, Clostridium, Intestinimonas, and Acetatifactor while decreasing potential pathobionts including Helicobacter. These findings of antioxidative and anti-inflammatory effects in the brain and ameliorative effects on epithelial integrity, SCFAs and microbiota in the gut, provide novel insights into the effect of EPSRam12 intervention on the gut–microbiome–brain axis and should facilitate prospective understanding of microbial exopolysaccharide for improved host health.

Update on new trend and progress of the mechanism of polysaccharides in the intervention of Alzheimer's disease, based on the new understanding of relevant theories: A review

Alzheimer's disease (AD), a neurodegenerative disease with insidious onset and progressive progression, is the main type of dementia. Currently, there is no specific cure for the disease. At the same time, a series of drug developments based on the classic theory, the Aβ cascade hypothesis, have not completed phase III clinical trials, challenging the hypothesis. Polysaccharides obtained from natural products can be used in the treatment of AD, which has attracted academic attention due to its advantages of multi-target, multi-channel, no or modest side effects. The TCM syndrome type of AD is mainly "qi and blood deficiency, kidney essence deficiency", and the medicine is mainly used to replenish qi and blood, kidney and bone marrow. Thus, there has been extensive and in-depth research on polysaccharides obtained from tonic Chinese herbal medicine in China. Based on this background, this paper evaluated the effects and mechanisms of natural polysaccharides on AD by combing and screening English and related literature in recent 5 years and summarized the extraction process and structure-activity relationship of polysaccharides.

Protective Effects of Polysaccharides in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are characterized by progressive degeneration and necrosis of neurons, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease and others. There are no existing therapies that correct the progression of these diseases, and current therapies provide merely symptomatic relief. The use of polysaccharides has received significant attention due to extensive biological activities and application prospects. Previous studies suggest that the polysaccharides as a candidate participate in neuronal protection and protect against NDs. In this review, we demonstrate that various polysaccharides mediate NDs, and share several common mechanisms characterized by autophagy, apoptosis, neuroinflammation, oxidative stress, mitochondrial dysfunction in PD and AD. Furthermore, this review reveals potential role of polysaccharides in vitro and in vivo models of NDs, and highlights the contributions of polysaccharides and prospects of their mechanism studies for the treatment of NDs. Finally, we suggest some remaining questions for the field and areas for new development.

Potential for non-starch polysaccharides in the prevention and remediation of cognitive impairment: A comprehensive review

Non-starch polysaccharides (NSPs) are food ingredients proven to be beneficial in a large number of health issues. However, there is no literature systematic review about the effects and corresponding mechanisms of NSPs on the prevention and remediation of cognitive impairment. In this review, studies on prevention and remediation of NSPs for cognitive deficit caused by diseases, menopause, ageing, chronic stress and environmental pollutants were summarized and the corresponding mechanisms were established. The anti-cognitive deficit effects of NSPs were associated with the modulation of amyloid β (Aβ) deposition, p-Tau aggregation, oxidative stress, inflammation, neuron apoptosis, neurogenesis, neurotransmitters, synaptic plasticity, autophagy and gut microbiota. Although the structure-function relationship has not been elucidated, several structural properties of NSPs such as molecular weight, sulfate content, hydroxyl group content, monosaccharide composition and molecular chain linkage might be crucial for the anti-cognitive deficit property. Notably, this review revealed that NSPs had a positive effect on cognitive impairment and proposed the future perspectives for further research on the anti-cognitive dysfunction effects of NSPs.

Marked Response of Rat Ileal and Colonic Microbiota After the Establishment of Alzheimer’s Disease Model With Bilateral Intraventricular Injection of Aβ (1-42)

Alzheimer’s disease (AD) is a common neurodegenerative disease. More evidence has shown that gut microbiota is closely associated with AD. Also, studies have shown that the distribution of gut microbiota vary in different sections of the intestine. In this study, a rat model of AD was established using a bilateral intraventricular injection of β-amyloid (1-42) [Aβ (1-42)], and the behavior of rats, hippocampal Aβ (1-42) deposition, and the ileal and colonic microbiota in each group were analyzed. We observed that the model rats had obvious memory and cognitive impairment, increased Aβ (1-42) deposition, indicating that the AD model was successfully established. Through 16S rRNA-sequencing analysis, we found that α diversity, β diversity, and dominant microbiota in the ileum and colon of normal rats were significantly different, showing spatial heterogeneity. Additionally, the surgery and injection of Aβ (1-42) caused various degrees of disturbances in the ileal and colonic microbiota of rats. These findings provide new insights for the study of the gut microbiota of AD rats and help advance the development of therapeutic strategies for intervening AD through the gut microbiota.

Neuroprotective effects of naturally sourced bioactive polysaccharides: an update

Polysaccharides are macromolecular complexes that have various biological activities. In vivo and in vitro studies have shown that polysaccharides play neuroprotective roles through multiple mechanisms; consequently, they have potential in the prevention and treatment of neurodegenerative diseases. This paper summarizes related research published during 2015-2020 and reviews advances in the understanding of the neuroprotective effects of bioactive polysaccharides. This review focuses on 15 bioactive polysaccharides from plants and fungi that have neuroprotective properties against oxidative stress, apoptosis, neuroinflammation, and excitatory amino acid toxicity mainly through the regulation of nuclear factor kappa-B, phosphatidylinositol-3-kinase/protein kinase B, mitogen-activated protein kinase, nuclear factor-E2-related factor 2/ hemeoxygenase-1, c-jun N-terminal kinase, protein kinase B-mammalian target of rapamycin, and reactive oxygen species-nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 signaling pathways. Natural bioactive polysaccharides have potential in the prevention and treatment of neurodegenerative diseases because of their advantageous characteristics, including multi-targeting, low toxicity, and synergistic effects. However, most of the recent related research has focused on cell and animal models. Future randomized clinical trials involving large sample sizes are needed to validate the therapeutic benefits of these neuroprotective polysaccharides in patients having neurodegenerative diseases.

Qisheng Wan formula ameliorates cognitive impairment of Alzheimer's disease rat via inflammation inhibition and intestinal microbiota regulation

ETHNOPHARMACOLOGY RELEVANCE

Qisheng Wan formula (QWF) was first described in the book Sheng Ji Zong Lu in 1117. The book states that QWF can cure forgetfulness, improve the mind, and make people smart. Hence, QWF has been widely used to treat patients with forgetfulness or dementia. QWF, a classic Chinese formulation, comprises seven herbal drugs: the sclerotium of Poria cocos (Schw.) Wolf, bark of Cinnamomum cassia Presl, root of Polygala tenuifolia Willd., root and rhizome of Panax ginseng C. A. Mey., root of Asparagus cochinchinensis (Lour.) Merr., root and rhizome of Acorus tatarinowii Schott, and root bark of Lycium chinense Mill.

AIM OF THE STUDY

This study aimed to utilize modern pharmacological methods to evaluate the therapeutic effects and explore the underlying mechanism of QWF action on rats with Alzheimer's disease (AD).

MATERIALS AND METHODS

The chemical profile of QWF was characterized using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The AD rat model was established via a bilateral intraventricular injection of amyloid-β (1-42) (Aβ_1-42). The rats were subsequently treated daily with QWF for 4 weeks. The Morris water maze test was performed to evaluate the cognition processes in the rats, whereas histological changes in the hippocampus were observed using hematoxylin and eosin staining. The expression levels of Aβ_1-42, nuclear factor-kappa B (NF-κB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in the hippocampus and colon were assessed. Moreover, the diversity and composition of the intestinal microbiota were analyzed using 16S rDNA gene sequencing.

RESULTS

One hundred and fourteen compounds were characterized in QWF. QWF significantly ameliorated the cognition processes and histopathological damages due to AD in rats by decreasing the deposition of Aβ_1-42 and downregulating the expression of NF-κB, TNF-α, and IL-6. QWF also modulated changes in the diversity and composition of intestinal microbiota to suppress the relative abundance of inflammation-associated microbiota.

CONCLUSION

This study showed that QWF can suppress proinflammatory factors and modulate the intestinal microbiota in AD rats.

Plant polysaccharides utilized by gut microbiota: New players in ameliorating cognitive impairment

Considerable evidence indicates the important role of gut microbiota in human health. Through the interaction with the host and diet, it secretes a myriad of metabolites to modulate biological processes essential for health. Cognitive impairment is a common feature of psychiatric and neurological disorders, which may seriously damage the quality of patients' life. Studies have found that cognitive impairment has a close relationship with gut microbiota, and plant polysaccharides intervention to maintain intestinal micro-ecological balance has a great impact on ameliorating cognitive impairment. This review introduced the interaction between gut microbiota and plant polysaccharides, and focused on signaling pathogenesis of gut microbiota in cognitive impairment. The effect of plant polysaccharides intervention on regulation of gut microbiota was also discussed, so as to provide a promising strategy for ameliorating cognitive impairment.

Natural Polysaccharides as Preventive and Therapeutic Horizon for Neurodegenerative Diseases

Neurodegenerative diseases are a serious and widespread global public health burden amongst aging populations. The total estimated worldwide global cost of dementia was US$818 billion in 2015 and has been projected to rise to 2 trillion US$ by 2030. While advances have been made to understand different neurodegenerative disease mechanisms, effective therapeutic strategies do not generally exist. Several drugs have been proposed in the last two decades for the treatment of different types of neurodegenerative diseases, with little therapeutic benefit, and often with severe adverse and side effects. Thus, the search for novel drugs with higher efficacy and fewer drawbacks is an ongoing challenge in the treatment of neurodegenerative disease. Several natural compounds including polysaccharides have demonstrated neuroprotective and even therapeutic effects. Natural polysaccharides are widely distributed in plants, animals, algae, bacterial and fungal species, and have received considerable attention for their wide-ranging bioactivity, including their antioxidant, anti-neuroinflammatory, anticholinesterase and anti-amyloidogenic effects. In this review, we summarize different mechanisms involved in neurodegenerative diseases and the neuroprotective effects of natural polysaccharides, highlighting their potential role in the prevention and therapy of neurodegenerative disease.

Effects and mechanisms of natural products on Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in elderly people with a high incidence rate and complicated pathogenesis, and causes progressive cognitive deficit and memory impairment. Some natural products and bioactive compounds from natural sources show great potential in the prevention and treatment of AD, such as apple, blueberries, grapes, chili pepper, Monsonia angustifolia, cruciferous vegetables, Herba epimedii, Angelica tenuissima, Embelia ribes, sea cucumber, Cucumaria frondosa, green tea, Puer tea, Amanita caesarea and Inonotus obliquus, via reducing amyloid beta (Aβ) deposition, decreasing Tau hyperphosphorylation, regulating cholinergic system, reducing oxidative stress, inhibiting apoptosis and ameliorating inflammation. This review mainly summarizes the effects of some natural products and their bioactive compounds on AD with the potential molecular mechanisms.

Whole-plant foods and their macromolecules: untapped approaches to modulate neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder. Recently, sustained neuroinflammatory response in microglia and astrocytes has been found to cause the deposition of amyloid beta plaques and the hyperphosphorylation of tau protein, thereby accelerating AD progression. The lipoxin A4-transcription factor nuclear factor-kappa B and mitogen-activated protein kinase pathways have been shown to play important roles in the regulation of inflammatory processes. There is growing research-based evidence suggesting that dietary whole-plant foods, such as mushrooms and berries, may be used as inhibitors for anti-neuroinflammation. The beneficial effects of whole-plant foods were mainly attributed to their high contents of functional macromolecules including polysaccharides, polyphenols, and bioactive peptides. This review provides up-to-date information on important molecular signaling pathways of neuroinflammation and discusses the anti-neuroinflammatory effects of whole-plant foods. Further, a critical evaluation of plants' macromolecular components that have the potential to prevent and/or relieve AD is provided. This work will contribute to better understanding the pathogenetic mechanism of neuroinflammation in AD and provide new approaches for AD therapy.

Structural characterization of a novel Schisandra polysaccharides and nutritional intervention in immunotoxicity to PCBs

A new polysaccharide from fruits of Schisandra chinensis (SCPP22) with a molecular weight of 143 ± 0.13 KDa was mainly made up of glucose and galactose. The possible structure of SCPP22 was showed that its main chain was composed of 1,4-α-d-Glup and branch was stretched from O-6 position of 1,4-β-d-Glup. Branches consisted of T-α-d-Galp. Further, SCPP22 could reverse PCB126-induced immunosuppression, significantly enhance body weight and immune organ indices. It also significantly ameliorated oxidative injury to immune organ induced by PCB126, as shown by evaluation of SOD activities, as well as MDA levels in spleen and thymus. SCPP22 strongly stimulated cytokines production by up-regulating mRNA expression of TNF-α, INF-γ and IL-2. Mechanism investigation revealed that recovery effects of SCPP22 in immunosuppression induced by PCB126 are mainly through regulating apoptosis-related proteins expression. Schisandra polysaccharides might be applied in functional food as nutritional intervention ingredient.

Nootkatone improves anxiety- and depression-like behavior by targeting hyperammonemia-induced oxidative stress in D-galactosamine model of liver injury

Acute or chronic liver injury is closely related to hyperammonemia, which will result in oxidative stress and damage to nerve cells, and these factors are vital to the development of anxiety and depression. In this study, the effect of Nootkatone (NKT) on the anxiety- and depression-like behavioral changes in mice induced by liver injury was investigated. Liver injury was induced by D-galactosamine (D-GalN; 350 mg/kg) three times a week for 4 weeks. NKT (5 mg/kg or 10 mg/kg) was given as co-treatment daily for 4 weeks. NKT (5 mg/kg) co-treatment remarkably ameliorates D-GalN-induced anxiety- and depression-like behaviors as evident from the results of sucrose preference test, forced swimming test, tail suspension test, and novelty suppressed feeding test. Results showed that NKT could induce an elevation in serum alanine transaminase and aspartate transaminase level, alleviate the oxidative stress induced by hyperammonemia through activating Keap1/Nrf2/HO-1 antioxidant pathways, decrease the expression of inducible nitric oxide synthase and NOX2 in hippocampus and prefrontal cortex, enhance the vitality of superoxide dismutase, catalase, and glutathione levels in serum, liver, and brain, and significantly reduce the generation of malondialdehyde. At the same time, NKT also reduces the level of ammonia in serum and brain and upgrades the activity of glutamine synthetase in the hippocampus and prefrontal cortex. Taken together, the present results suggested that NKT has a significant antidepressant effect through modulation of oxidative stress induced by D-GalN administration.

The water-soluble non-starch polysaccharides from natural resources against excessive oxidative stress: A potential health-promoting effect and its mechanisms

The water-soluble non-starch polysaccharides isolated from natural resources have become research hotpots in the field of food science and human health due to widely distributed in nature and low toxicity. It has indicated that the health-promoting effect of water-soluble non-starch polysaccharides were partly attributable to against excessive oxidative stress. Indeed, excessive oxidative stress in the body has been reported in occurrence of disease. The water-soluble non-starch polysaccharides from natural resources exhibit antioxidant activity to against oxidative stress via scavenging free radicals promoting antioxidant enzymes activity and/or regulating antioxidant signaling pathways. In this review, the water-soluble non-starch polysaccharides as medicine agent and the factor affecting antioxidant as well as the relationship between oxidative stress and disease are summarized, and the mechanisms of water-soluble non-starch polysaccharides therapy in disease are also discussed. It will provide a theoretical basis for natural polysaccharides used for the treatment of diseases.

Determination and Comparison of Short-Chain Fatty Acids in Serum and Colon Content Samples: Alzheimer's Disease Rat as a Case Study

Short-chain fatty acids (SCFAs) are the main microbial fermentation products from dietary fibers in the colon, and it has been speculated that they play a key role in keeping healthy in the whole-body. However, differences in SCFAs concentration in the serum and colon samples had attracted little attention. In this study, we have optimized the extract and analysis methods for the determination of ten SCFAs in both serum and colon content samples. Methanol and acetonitrile were chosen for extraction of SCFAs from serum and colon content samples, respectively. Biological samples were collected from Alzheimer's disease rats treated by extract of Schisandra chinensis (Turcz.) Baill (SC-extract) were taken as research objects. The results showed that, the relative peak intensities of SCFAs in the colon content from all groups were quite similar, and the trend was identical in the serum samples. Compared with the values in humans, the ratio of ten SCFAs in rat's colon was similar, while the percent of acetate in rat's serum was significantly higher. For therapy of Alzheimer's disease (AD), SC-extract decreased the concentration of butyrate, 3-Methyvalerate, and caproate in the serum samples towards the trend of normal rats. This study may help our understanding of how SCFAs are transported across colonic epithelium in healthy and diseased organisms.

Neuroprotective effects of verbascoside against Alzheimer's disease via the relief of endoplasmic reticulum stress in Aβ-exposed U251 cells and APP/PS1 mice

BACKGROUND

Endoplasmic reticulum (ER) stress is involved in the progression of Alzheimer's disease (AD). Verbascoside (VB), an active phenylethanoid glycoside that was first isolated from Verbascum sinuatum (the wavyleaf mullein), possesses anti-inflammatory, antioxidative, and anti-apoptotic effects. The purpose of this study was to elucidate the beneficial effects of VB in amyloid β (Aβ)1-42-damaged human glioma (U251) cells and in APPswe/PSEN1dE9 transgenic (APP/PS1) mice.

METHODS

U251 cells were co-incubated with 10 μM of Aβ1-42 and treated with VB. The protective effects of VB were investigated by using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay, flow cytometry, fluorescence staining, and transmission electron microscopy. APP/PS1 transgenic mice were treated for 6 weeks with VB. Learning and memory were evaluated using a Morris water maze test. Immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling, thioflavin-S staining, and proteomics analysis were performed to study the potential neuroprotective mechanism. Enzyme-linked immunosorbent assays and western blot were performed to analyze altered protein levels of brain lysates in APP/PS1 mice and/or Aβ1-42-damaged U251 cells.

RESULTS

In Aβ1-42-damaged U251 cells, VB significantly improved cell viability, inhibited apoptosis, reduced calcium accumulation and the intracellular concentrations of reactive oxygen species, and improved the morphology of mitochondria and ER. In APP/PS1 mice, 6-week administration of VB significantly improved memory and cognition. VB inhibited apoptosis, reduced the deposition of Aβ, reduced the formation of neurofibrillary tangles formed by hyperphosphorylated tau protein, and downregulated the expression levels of 4-hydroxynonenal and mesencephalic astrocyte-derived neurotrophic factor in the brains of APP/PS1 mice. Proteomics analysis of mouse hippocampus suggested that the neuroprotective effect of VB may be related to the reduction of ER stress. This was indicated by the fact that VB inhibited the three branches of the unfolded protein response, thereby attenuating ER stress and preventing apoptosis.

CONCLUSIONS

The results confirmed that VB possesses significant neuroprotective effects, which are related to the reduction of ER stress. These findings support the status of VB as a potentially effective treatment for AD and warrant further research.

Schisandra chinensis ameliorates depressive-like behaviors by regulating microbiota-gut-brain axis via its anti-inflammation activity

The present study aimed to examine the antidepressant actions of the composition fractions of Schisandra chinensis using LPS-induced mice. Animals were treated with total extracts (SCE), lignans (SCL), polysaccharides (SCPS), and essential oil (SCVO), and then subjected to behavioral tests. The forced swimming test (FST) and tail suspension test (TST) were used as predictive animal models of antidepressant activity. Total extracts and lignans significantly decreased the duration of immobility in FST and TST. We found that treatment with SCE and SCL could significantly decrease the levels of pro-inflammatory cytokines both in the periphery and central nervous system (CNS). This was confirmed by the histopathological examination of the colon. The RT-PCR results demonstrated that SCE and SCL could greatly inhibit the TLR4/NF-κB/IKKα signaling pathway. In addition, the concentrations of Butyric acid and Propionic acid were upregulated by the administration, and the decreased diversity of intestinal microbiota and alterations of the relative proportions of Bacteroidetes and Firmicutes phylum members, Barnesiella and Lactobacillus genus members in LPS-induced mice were restored as well. All results suggested that lignans is the effective fraction of S.chinensis to ameliorating depressive disorders, which its anti-inflammation activity possibly involved in the bidirectional connection between gut microbiota and brain.

Polysaccharide from Schisandra chinensis acts via LRP-1 to reverse microglia activation through suppression of the NF-κB and MAPK signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis (Turcz.) Baill (S. Chinensis), a traditional Chinese medicine frequently used in the traditional treatment of dementia, its polysaccharide component has been widely reported.

AIM OF THE STUDY

In this paper, we studied whether SCP2-1, a natural product of homogeneous polysaccharide from S. Chinensis, could improve M1 and M2 polarization and inhibit neuroinflammation through lipoprotein receptor-related protein-1 (LRP-1), and futher exerted anti-inflammatory and neuroprotective effects.

MATERIALS AND METHODS

SCP2-1 was obtained from crude polysaccharide of S. Chinensis, BV2 microglia cells and mice stimulated by LPS were served to detect the positive role of SCP2-1 in M1/M2 polarization. The concentration of cytokine expression, IL-1β, TNF-α, IL-12 and IL-6 for M1 polarization and TGF-β, IL-10, IL-4 and Arg-1 for M2 polarization, in the BV2 and hippocampus were tested by ELISA kits. CD86 and CD206, as surface markers of M1 and M2, were tested by flow cytometry. We examined the expression of LRP-1 in BV2 cells and mouse hippocampus. The addition of siRNA for LRP-1 demonstrated the important role of LRP-1 in the neuroprotection of SCP2-1. Western blot was used to detect the activation of various mitogen-activated protein kinase (MAPKs) pathway, i.e. the phosphorylation of JNK and ERK proteins, and nuclear translocation of nuclear factor κB (NF-κB). H.E. staining was used to observe Histopathological changes.

RESULTS

SCP2-1 could reverse M1/M2 polarization in vitro culture and suppressed M1 polarization in the hippocampus of mice stimulated with LPS. After LPS stimulation, poor levels of LRP-1, hyperactivation of the JNK and NF-κB was appeared, which could improve by SCP2-1. The addition of siRNA for LRP-1 suppressed the protection of SCP2-1 in BV2 microglial cells. More importantly, SCP2-1 could improve LPS-induced cognitive dysfunction in mice in Y-maze and NOR test.

CONCLUSIONS

SCP2-1 could improve M1/M2 polarization, especially inhibit M1 polarization, and ameliorate the cognition of mice in Y-maze and NOR test. SCP2-1 play a neuroprotective role through LRP-1 to reverse activation of microglia via suppressing the overactive NF-κB and JNK pathway.

DHA attenuates Aβ-induced necroptosis through the RIPK1/RIPK3 signaling pathway in THP-1 monocytes

Monocytes play a crucial role in Alzheimer's disease (AD), and docosahexaenoic acid (DHA) has a neuroprotective effect for many neurodegenerative diseases. However, mechanisms that regulate monocyte and Aβ protein interaction in AD and the effects of DHA on monocytes in the context of AD are not fully understood. The experiments were designed to further explore possible mechanisms of interaction between monocytes and Aβ plaques. Another objective of this study was to investigate a potential mechanism for Aβ-induced necroptosis involving the activation of MAPK and NF-kB signaling pathways in human THP-1 monocytes, as well as how these pathways might be modulated by DHA. Our findings indicate that Aβ25-35 has a "Hormesis" effect on cell viability and necroptosis in THP-1 cells, and Aβ25-35 influences THP-1 cells differentiation as analyzed by flow cytometry. Pretreatment of THP-1 monocytes with DHA effectively inhibited Aβ-induced activation and markedly suppressed protein expression of necroptosis (RIPK1, RIPK3, MLKL) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). Moreover, our findings indicate that Aβ25-35 activated the ERK1/2 and p38 signaling pathways, but not NF-κB/p65 signaling, while pre-treatment with DHA followed by Aβ25-35 treatment suppressed only ERK1/2 signaling. Further study revealed that the expression level of RIPK3 is reduced much more during coadministration with DHA and necrostatin-1 (NEC-1) than administration alone with either of them, indicating that DHA may have additional targets. Meanwhile, this finding indicates that DHA can prevent Aβ-induced necroptosis of THP-1 cells via the RIPK1/RIPK3 signaling pathway. Our results also indicate that DHA treatment restored migration of THP-1 monocytes induced by Aβ25-35, and DHA treatment could be a promising new therapy for AD management.

Pharmacodynamic material basis of traditional Chinese medicine based on biomacromolecules: a review

Biomacromolecules, the first components of bioactive substances in traditional Chinese medicines (TCM) have wide bioactivity-related efficacy but have not yet been fully appreciated compared to small molecule components. The present review brings a novel and systemic point of view to deepen the understanding of the pharmacodynamic material basis of TCM based on biomacromolecules (polysaccharides, proteins and nucleic acids). Biomacromolecules have been, are and will have considerable roles in the efficacy of Chinese medicine, as evidenced by the number of biological activities related to traditional clinical efficacy. The direct and indirect mechanisms of biomacromolecules are further accounted for in a variety of neurotransmitters, hormones, and immune substances to maintain immune function in both sensitive and stable equilibrium. The biological functions of biomacromolecules have been elaborated on in regard to their roles in the process of plant growth and development to the relationship between primary metabolism and secondary metabolism and to the indispensable role of polysaccharides, proteins, and nucleic acids in the quality formation of TCM. Understanding the functional properties and mechanisms of biological macromolecules will help to demystify the drug properties and health benefits of TCM.