Astragalus mongholicus Bunge (Fabaceae): Bioactive Compounds and Potential Therapeutic Mechanisms Against Alzheimer's Disease

Astragaloside IV promotes cerebral tissue restoration through activating AMPK- mediated microglia polarization in ischemic stroke rats

ETHNOPHARMACOLOGICAL RELEVANCE

Astragaloside IV (AS), a key active ingredient obtained from Chinese herb Astragalus mongholicus Bunge, exerts potent neuroprotective and anti-inflammatory effects for treating neurodegenerative diseases. However, mechanisms of AS on improvement of ischemic brain tissue repair remain unclear.

AIM OF THE STUDY

This research aims at using magnetic resonance imaging (MRI) to noninvasively determine whether AS facilitates brain tissue repair, and investigating whether AS exerts brain remodeling through adenosine monophosphate-activated protein kinase (AMPK) metabolic signaling regulating key glycolytic enzymes and energy transporters, thereby impacting microglia polarization.

MATERIALS AND METHODS

Ischemic stroke model in male Sprague-Dawley rats were induced through permanent occlusion of the middle cerebral artery (MCAO). Infarct volume, the alterations of brain microstructure and nerve fibers reorganization were examined by multi-parametric MRI. The pathological damages of myelinated axons and microglia polarization surrounding infarct tissue were detected using pathological techniques. Furthermore, M1/M2 microglia polarization associated protein, glycolytic rate-limiting enzymes, energy transporters and AMPK/mammalian target of rapamycin (mTOR)/hypoxia inducible factor-1α (HIF-1α) signal were examined both in ischemic stroke rats and BV2 microglia treated with lipopolysaccharide (LPS) + interferon-γ (IFN-γ) by western blotting.

RESULTS

MRI revealed that AS obviously decreased infarct volume, relieved brain microstructure damage and improved nerve fibers reorganization in ischemic stroke rats. Histological tests supported MRI findings. Notably, AS promoted microglia M2 and reduced M1 polarization, induced the AMPK activation accompanied with decreased levels of phosphorylated mTOR and HIF-1α. Moreover, AS suppressed the expression of glycolytic rate-limiting enzymes and energy transporters in ischemic stroke rats and BV2 microglia. In contrast, these beneficial effects were greatly blocked by AMPK inhibitor compound C.

CONCLUSION

Overall, these results collectively suggested that AS facilitated tissue remodeling that may be partially through modulating polarization of microglia in AMPK- dependent metabolic pathways after ischemic stroke.

Metabolomics combined with network pharmacology reveals the protective effect of astragaloside IV on alcoholic liver disease

BACKGROUND

Alcoholic liver disease (ALD) is a significant contributor to liver damage. However, the clinical options for the treatment of ALD are limited. Astragaloside IV (AST-IV) is a saponin isolated from Astragalus membranaceus (AM). This study aimed to explore the underlying mechanisms of action of AST-IV in ALD by integrating metabolomics and network pharmacology.

METHODS

Sprague-Dawley (SD) rats were used to establish a rat model of ALD. AST-IV and polyene phosphatidyl choline (PPC; a positive control drug) were administered to rats with ALD for 4 weeks. We measured the body weight, liver index, ALT, AST, TC, TG, inflammatory markers (IL-1β, IL-6, and TNF-α), and oxidative stress markers (SOD, MDA) and used H&E and ORO staining to evaluate the hepatoprotective effect of both AST-IV and PPC on ALD. Subsequently, we performed untargeted metabolomics to predict the influence of AST-IV on lipid metabolism in rats with ALD. We then used a network pharmacology approach to identify the core targets through which AST-IV corrected lipid metabolism disorders and validated these targets through molecular docking, qRT-PCR and western blot analyses. Finally, we calculated the relationships between ALD-related biochemical markers, differential liver metabolites, and core targets using Spearman's correlation analysis.

RESULTS

AST-IV improved pathological damage and reduced lipid accumulation in the hepatocytes of rats with ALD. Furthermore, AST-IV inhibited oxidative stress and inflammatory responses in rats with ALD. The metabolomic results showed that AST-IV corrected hepatic lipid metabolism disorders by targeting linoleic acid, necrosis, sphingolipid, and glycerophospholipid metabolism. The Network pharmacology analysis revealed that the core targets of AST-IV exerting the above effects were p-RIPK3, p-MLKL, CYP1A2, CYP2C19, PPARα, PCSK9. Spearman's correlation analysis showed a strong correlation between ALD-related serum biochemical indices, core targets, and liver differential metabolites.

CONCLUSION

AST-IV corrects the metabolic disorders of linoleic acid, sphingolipid, and glycerophospholipid, and alleviates necrosis in rats with ALD through the core targets p-RIPK3, p-MLKL, CYP1A2, CYP2C19, PPARα, and PCSK9. This study is the first to reveal the mechanism of ALD protection through AST-IV from the perspective of metabolomics and network pharmacology. Therefore, a novel target has been identified to exert protection against ALD. This study provides a reference for ALD treatment.

Untargeted metabolomics reveals intervention effects of wine-processed Schisandra chinensis polysaccharide on Alzheimer's disease mice

Schisandra chinensis (Turcz.) Baill (SC) is a traditional sedative in China, with wide applications for treating various neurological disorders. Its polysaccharide component has been gaining increased attention for its potential in nerve protection. While raw SC is the primary focus of current research, its processed products are primarily utilized as clinical medicines. Notably, limited research exists on the mechanisms underlying the effects of wine-processed Schisandra chinensis polysaccharide (WSCP) in Alzheimer's Disease (AD). Therefore, this study seeks to assess the therapeutic impact of WSCP on AD mice and investigate the underlying mechanisms through biochemical and metabolomics analyses. The results demonstrate that WSCP exerts significant therapeutic effects on AD mice by enhancing learning and memory abilities, mitigating hippocampal neuronal damage, reducing abnormal amyloid-beta (Aβ) deposition, and attenuating hyperphosphorylation of Tau. Biochemical analysis revealed that WSCP can increase SOD content and decrease MDA, IL-6, and TNF-α content in AD mice. Furthermore, serum metabolomic results showed that WSCP intervention can reverse metabolic disorders in AD mice. 43 endogenous metabolites were identified as potential biomarkers for WSCP treatment of AD, and the major metabolic pathways were Ala, Glu and Asp metabolism, TCA cycle. Overall, these findings will provide a basis for further development of WSCP.

Effects of Cycloastragenol on Alzheimer's Disease in Rats by Reducing Oxidative Stress, Inflammation, and Apoptosis

BACKGROUND

As individuals age, they may develop Alzheimer's disease (AD), which is characterized by difficulties in speech, memory loss, and other issues related to neural function. Cycloastragenol is an active ingredient of Astragalus trojanus and has been used to treat inflammation, aging, heart disease, and cancer.

OBJECTIVES

This study aimed to explore the potential therapeutic benefits of cycloastragenol in rats with experimentally induced AD. Moreover, the underlying molecular mechanisms were also evaluated by measuring Nrf2 and HO-1, which are involved in oxidative stress, NFκB and TNF-α, which are involved in inflammation, and BCL2, BAX, and caspase-3, which are involved in apoptosis.

METHODS

Sprague-Dawley rats were given 70 mg/kg of aluminum chloride intraperitoneally daily for six weeks to induce AD. Following AD induction, the rats were given 25 mg/kg of cycloastragenol daily by oral gavage for three weeks. Hippocampal sections were stained with hematoxylin/ eosin and with anti-caspase-3 antibodies. The Nrf2, HO-1, NFκB, TNF-α, BCL2, BAX, and caspase-3 gene expressions and protein levels in the samples were analyzed.

RESULTS

Cycloastragenol significantly improved rats' behavioral test performance. It also strengthened the organization of the hippocampus. Cycloastragenol significantly improved behavioral performance and improved hippocampal structure in rats. It caused a marked decrease in the expression of NFκB, TNF-α, BAX, and caspase-3, which was associated with an increase in the expression of BCL2, Nrf2, and HO-1.

CONCLUSION

Cycloastragenol improved the structure of the hippocampus in rats with AD. It enhanced the outcomes of behavioral tests, decreased the concentration of AChE in the brain, and exerted antioxidant and anti-inflammatory effects. Antiapoptotic effects were also noted, leading to significant improvements in cognitive function, memory, and behavior in treated rats.

Identifying the Anti-inflammatory Effects of Astragalus Polysaccharides in Anti-N-Methyl-D-Aspartate Receptor Encephalitis: Network Pharmacology and Experimental Validation

BACKGROUND

Astragalus polysaccharides (APS), a group of bioactive compounds obtained from the natural source Astragalus membranaceus (AM), exhibits numerous pharmacological actions in the central nervous system, such as anti-inflammatory, antioxidant, and immunomodulatory properties. Despite the remarkable benefits, the effectiveness of APS in treating anti- N-methyl-D-aspartate receptor (NMDAR) encephalitis and the corresponding mechanism have yet to be fully understood. As such, this study aims to investigate the impact of APS on anti-NMDAR encephalitis and explore the potential molecular network mechanism.

METHODS

The impact of APS intervention on mice with anti-NMDAR encephalitis was assessed, and the possible molecular network mechanism was investigated utilizing network pharmacology and bioinformatics techniques such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG),protein-protein interaction (PPI) network, and molecular docking. Enzymelinked immunosorbent assay (ELISA) was applied to detect the expression of core target proteins.

RESULTS

APS significantly ameliorated cognitive impairment and reduced susceptibility to PTZinduced seizures in mice with anti-NMDAR encephalitis, confirming the beneficial effect of APS on anti-NMDAR encephalitis. Seventeen intersecting genes were identified between APS and anti- NMDAR encephalitis. GO and KEGG analyses revealed the characteristics of the intersecting gene networks. STRING interaction in the PPI network was applied to find crucial molecules. The results of molecular docking suggested that APS may regulate interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) as potential targets in anti-NMDAR encephalitis. Furthermore, the levels of IL-1β, IL-6, and TNF-α detected by ELISA in anti-NMDAR encephalitis mice were significantly downregulated in response to the administration of APS.

CONCLUSION

The findings of this study demonstrate the significant role of APS in the treatment of anti-NMDAR encephalitis, as it effectively suppresses inflammatory cytokines. These results suggest that APS has the potential to be considered as a viable herbal medication for the treatment of anti-NMDAR encephalitis.

Palmatine Protects PC12 Cells and Mice from Aβ25-35-Induced Oxidative Stress and Neuroinflammation via the Nrf2/HO-1 Pathway

Alzheimer's disease is a common degenerative disease which has a great impact on people's daily lives, but there is still a certain market gap in the drug research about it. Palmatine, one of the main components of Huangteng, the rattan stem of Fibraurea recisa Pierre (Menispermaceae), has potential in the treatment of Alzheimer's disease. The aim of this study was to evaluate the neuroprotective effect of palmatine on amyloid beta protein 25-35-induced rat pheochromocytoma cells and AD mice and to investigate its mechanism of action. CCK8 assays, ELISA, the Morris water maze assay, fluorescent probes, calcein/PI staining, immunofluorescent staining and Western blot analysis were used. The experimental results show that palmatine can increase the survival rate of Aβ25-35-induced PC12 cells and mouse hippocampal neurons, reduce apoptosis, reduce the content of TNF-α, IL-1β, IL-6, GSH, SOD, MDA and ROS, improve the learning and memory ability of AD mice, inhibit the expression of Keap-1 and Bax, and promote the expression of Nrf2, HO-1 and Bcl-2. We conclude that palmatine can ameliorate oxidative stress and neuroinflammation produced by Aβ25-35-induced PC12 cells and mice by modulating the Nrf2/HO-1 pathway. In conclusion, our results suggest that palmatine may have a potential therapeutic effect on AD and could be further investigated as a promising therapeutic agent for AD. It provides a theoretical basis for the development of related drugs.

Effect of acupuncture on neuroinflammation in animal models of Alzheimer's disease: A preclinical systematic review and meta-analysis

Background

Despite neuroinflammation being an important component of the pathology of Alzheimer's disease (AD), effective therapies to alleviate neuroinflammation are still lacking. Many animal experiments in AD have found that acupuncture may ameliorate cognition by decreasing neuroinflammation and modulating cytokines, but its effects have not been systematically examined. We aimed to assess its efficacy on neuroinflammation in AD and to investigate the potential mechanisms.

Materials and methods

The following databases were searched from inception until 24 August 2022: Web of Science, EMBASE, PubMed, the Cochrane Library, and China National Knowledge Infrastructure. Animal studies that reported the efficacy of acupuncture on neuroinflammation in AD were included. The SYRCLE Robt was utilized to evaluate methodological quality. Stata 17 was utilized to conduct a meta-analysis of cytokine levels and the results of the Morris water maze.

Results

23 studies were included, with a total of 417 rats/mice. The overall quality of all included reports was medium. The results indicated that acupuncture significantly reduced the expressions of pro-inflammatory cytokines which included IL-1β [SMD = -3.50, 95% CI (-4.31, -2.69); I 2 = 78.6%] (P < 0.05), TNF-α [SMD = -3.05, 95% CI (-3.86, -2.24); I 2 = 69.6%] (P < 0.05), IL-6 [SMD = -3.22, 95% CI (-4.62, -1.81); I 2 = 77.6%] and enhanced the expressions of anti-inflammatory cytokines including IL-4 [SMD = 2.77, 95% CI (1.95, 3.59); I 2 = 33.9%] (P < 0.05), IL-10 [SMD = 1.84, 95% CI (1.20, 2.49); I 2 = 41.0%] (P < 0.05) in an animal model of AD. Regarding the Morris water maze, compared to the control group, the acupuncture group showed a shorter escape latency [SMD = -2.23, 95% CI (-2.89, -1.57); I 2 = 79.2%] (P < 0.05), longer duration in platform quadrant [SMD = 2.34, 95% CI (1.44, 3.23); I 2 = 81.7%] (P < 0.05), and increased platform crossing number [SMD = 2.79, 95% CI (2.06, 3.53); I 2 = 71.9%] (P < 0.05).

Conclusion

Acupuncture may reduce neuroinflammation in AD by modulating cytokine expression. This modulation significantly improved cognitive function in animal models of AD.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022354878.

Effect of Chinese herbal medicine therapy on risks of all-cause mortality, infections, parasites, and circulatory-related mortality in HIV/AIDS patients with neurological diseases

Introduction: Long-term living with human immunodeficiency virus (HIV) and/or antiretroviral therapy (ART) is associated with various adverse effects, including neurocognitive impairment. Heterogeneous neurocognitive impairment remains an important issue, affecting between 15-65% of human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) patients and resulting in work performance, safety, and health-related outcomes that have a heavy economic burden. Methods: We identified 1,209 HIV/AIDS patients with neurological diseases during 2010-2017. The Kaplan-Meier method, log-rank test, and Cox proportional hazards model were used to analyze 308 CHM users and 901 non-CHM users within this population. Major CHM clusters were determined using association rule mining and network analysis. Results and Discussion: Results showed that CHM users had a 70% lower risk of all-cause mortality (adjusted hazard ratio (aHR) = 0.30, 95% confidence interval (CI):0.16-0.58, p < 0.001) (p = 0.0007, log-rank test). Furthermore, CHM users had an 86% lower risk of infections, parasites, and circulatory-related mortality (aHR = 0.14, 95% confidence interval (CI):0.04-0.46, p = 0.001) (p = 0.0010, log-rank test). Association rule mining and network analysis showed that two CHM clusters were important for patients with neurological diseases. In the first CHM cluster, Huang Qin (HQ; root of Scutellaria baicalensis Georgi), Gan Cao (GC; root of Glycyrrhiza uralensis Fisch.), Huang Lian (HL; root of Coptis chinensis Franch.), Jie Geng (JG; root of Platycodon grandiflorus (Jacq.) A.DC.), and Huang Bai (HB; bark of Phellodendron amurense Rupr.) were identified as important CHMs. Among them, the strongest connection strength was identified between the HL and HQ. In the second CHM cluster, Suan-Zao-Ren-Tang (SZRT) and Ye Jiao Teng (YJT; stem of Polygonum multiflorum Thunb.) were identified as important CHMs with the strongest connection strength. CHMs may thus be effective in treating HIV/AIDS patients with neurological diseases, and future clinical trials are essential for the prevention of neurological dysfunction in the population.

The role of Phosphodiesterase-1 and its natural product inhibitors in Alzheimer's disease: A review

Phosphodiesterase-1 (PDE1) is a versatile enzyme that has surprisingly received considerable attention as a possible therapeutic target in Alzheimer's disease (AD) because it maintains the homeostasis of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) in the brain. 3',5'-cyclic adenosine monophosphate and 3',5'-cyclic guanosine monophosphate are the two key second messengers that regulate a broad range of intracellular processes and neurocognitive functions, specifically memory and cognition, associated with Alzheimer's disease. However, the lack of available selective drugs on the market poses challenges to identifying the beneficial effects of natural products. The present review focuses on Phosphodiesterase-1 and its isoforms, splicing variants, location, distribution, and function; the role of Phosphodiesterase-1 inhibitors in Alzheimer's disease; and the use of vinpocetine and natural products as specific Phosphodiesterase-1 inhibitors. Moreover, it aims to provide ongoing updates, identify research gaps, and present future perspectives. This review indicates the potential role of Phosphodiesterase-1 inhibitors in the treatment of neurodegenerative disorders, such as Alzheimer's disease. Certain clinical trials on the alleviation of Alzheimer's disease in patients are still in progress. Among de novo outcomes, the employment of Phosphodiesterase-1 inhibitors to treat Alzheimer's disease is an important advancement given the absence of particular therapies in the pipeline for this highly prevalent disease. To sum up, Phosphodiesterase-1 inhibition has been specifically proposed as a critical therapeutic approach for Alzheimer's disease. This study provides a comprehensive review on the biological and pharmacological aspects of Phosphodiesterase-1, its role on the Alzheimer's diseases and its significance as Alzheimer's disease therapeutic target in drug discovery from natural products. This review will help clinical trials and scientific research exploring new entities for the treatment and prevention of Alzheimer's disease.