Active constituent of Polygala tenuifolia attenuates cognitive deficits by rescuing hippocampal neurogenesis in APP/PS1 transgenic mice

Study on the role of Dihuang Yinzi in regulating the AMPK/SIRT1/PGC-1α pathway to promote mitochondrial biogenesis and improve Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Dihuang Yinzi (DHYZ) is a classic prescription in traditional Chinese medicine. Its therapeutic effect on Alzheimer's disease (AD) has been widely validated. However, the underlying molecular mechanisms of DHYZ in AD treatment remain unclear and require further research.

AIM OF THE STUDY

Elucidating DHYZ's promotion of mitochondrial biogenesis through the AMPK/SIRT1/PGC-1α pathway improves neuronal loss, mitochondrial damage, and memory deficits in AD.

MATERIALS AND METHODS

Administering DHYZ by gavage to SAMP8 mice, after completing behavioral tests, the effects of DHYZ on hippocampal neuron loss and mitochondrial structural damage in AD model mice were assessed using Nissl staining and transmission electron microscopy. Western blot was used to detect the expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, mitochondrial fusion protein MFN2, and mitochondrial fission proteins DRP1 and FIS1. At the same time, immunofluorescence (IF) was employed to measure the relative fluorescence intensity of mitochondrial fusion protein MFN1. After determining the optimal dose of DYHZ for treating AD, we conducted mechanistic studies. By intraperitoneally injecting SAMP8 mice with the AMPK inhibitor (Compound C) to inhibit AMPK protein expression and subsequently treating them with DHYZ, the impact of DHYZ on hippocampal neurons in AD model mice was evaluated using Nissl and hematoxylin-eosin staining. Western blot was used to detect the protein expression of AMPK, p-AMPK, SIRT1, PGC-1α, NRF1, and TFAM. In contrast, IF was used to measure the relative fluorescence intensity of PGC-1α, NRF1, and TFAM proteins in the hippocampal CA1 region.

RESULTS

DHYZ significantly improved AD model mice's cognitive impairment and memory deficits and mitigated hippocampal neuron loss and degeneration. Additionally, it ameliorated mitochondrial morphological structures. DHYZ upregulated the protein expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, and mitochondrial fusion proteins MFN1 and MFN2 while inhibiting the expression of mitochondrial fission proteins DRP1 and FIS1. Further studies revealed that DHYZ could upregulate the expression of the AMPK/SIRT1/PGC-1α pathway proteins and their downstream proteins NRF1 and TFAM.

CONCLUSION

DHYZ promotes mitochondrial biogenesis by activating the AMPK/SIRT1/PGC-1α signaling pathway, thereby improving memory deficits, neuronal loss, and mitochondrial dysfunction in AD.

A review of the botany, metabolites, pharmacology, toxicity, industrial applications, and processing of Polygalae Radix: the "key medicine for nourishing life"

Polygalae radix (PR) is the dried root of Polygala tenuifolia Willd. and Polygala sibirica L. and enjoys the reputation as the "key medicine for nourishing life." In this study, information about "Polygala tenuifolia Willd.," "Polygala sibirica L.," and "Yuanzhi" was retrieved from scientific databases, including Google Scholar, Baidu Scholar, Web of Science, PubMed, CNKI, and Wan Fang Data. Information from Chinese herbal medicine classics, Yaozhi Data, and the Gaide Chemical Network was also collected. Information related to botany, phytochemistry, pharmacology, toxicity, industrial applications, and processing is summarized in this paper to tap its potentialities and promote its further development and clinical application. More than 320 metabolites have been isolated from PR; saponins, xanthones, and oligosaccharide esters are the main functional metabolites. Pharmacological research shows that its pharmacological action mainly focuses on resisting nervous system diseases, and it also has the functions of anti-oxidation, anti-inflammation, anti-tumor, anti-pathogenic microorganisms and others. The gastrointestinal irritation of its saponins impeded its application, but this irritation can be reduced by controlling the dosage, compatibility with other herbs, or processing. The future progress of PR faces opportunities and challenges. More attention should be paid to the traditional application and processing methods of PR recorded in ancient books. The lack of safety and clinical studies has limited its application and transformation of achievements. Moreover, it is one-sided to take the content of only a few metabolites as the index of processing optimization and quality control, which cannot reflect the full pharmacological and toxicological activities of PR.

Bioinformatic analysis of hippocampal histopathology in Alzheimer's disease and the therapeutic effects of active components of traditional Chinese medicine

Background and aim

Pathological changes in the central nervous system (CNS) begin before the clinical symptoms of Alzheimer's Disease (AD) manifest, with the hippocampus being one of the first affected structures. Current treatments fail to alter AD progression. Traditional Chinese medicine (TCM) has shown potential in improving AD pathology through multi-target mechanisms. This study investigates pathological changes in AD hippocampal tissue and explores TCM active components that may alleviate these changes.

Methods

GSE5281 and GSE173955 datasets were downloaded from GEO and normalized to identify differentially expressed genes (DEGs). Key functional modules and hub genes were analyzed using Cytoscape and R. Active TCM components were identified from literature and the Pharmacopoeia of the People's Republic of China. Enrichment analyses were performed on target genes overlapping with DEGs.

Result

From the datasets, 76 upregulated and 363 downregulated genes were identified. Hub genes included SLAMF, CD34, ELN (upregulated) and ATP5F1B, VDAC1, VDAC2, HSPA8, ATP5F1C, PDHA1, UBB, SNCA, YWHAZ, PGK1 (downregulated). Literature review identified 33 active components from 23 herbal medicines. Target gene enrichment and analysis were performed for six components: dihydroartemisinin, berberine, naringenin, calycosin, echinacoside, and icariside II.

Conclusion

Mitochondrial to synaptic vesicle dysfunction pathways were enriched in downregulated genes. Despite downregulation, UBB and SNCA proteins accumulate in AD brains. TCM studies suggest curcumin and echinacoside may improve hippocampal pathology and cognitive impairment in AD. Further investigation into their mechanisms is needed.

Saponin components in Polygala tenuifolia as potential candidate drugs for treating dementia

Objective

This study aims to elucidate the intervention effects of saponin components from Polygala tenuifolia Willd (Polygalaceae) on dementia, providing experimental evidence and new insights for the research and application of saponins in the field of dementia.

Materials and Methods

This review is based on a search of the PubMed, NCBI, and Google Scholar databases from their inception to 13 May 2024, using terms such as "P. tenuifolia," "P. tenuifolia and saponins," "toxicity," "dementia," "Alzheimer's disease," "Parkinson's disease dementia," and "vascular dementia." The article summarizes the saponin components of P. tenuifolia, including tenuigenin, tenuifolin, polygalasaponins XXXII, and onjisaponin B, as well as the pathophysiological mechanisms of dementia. Importantly, it highlights the potential mechanisms by which the active components of P. tenuifolia prevent and treat diseases and relevant clinical studies.

Results

The saponin components of P. tenuifolia can reduce β-amyloid accumulation, exhibit antioxidant effects, regulate neurotransmitters, improve synaptic function, possess anti-inflammatory properties, inhibit neuronal apoptosis, and modulate autophagy. Therefore, P. tenuifolia may play a role in the prevention and treatment of dementia.

Conclusion

The saponin components of P. tenuifolia have shown certain therapeutic effects on dementia. They can prevent and treat dementia through various mechanisms.

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.

Jiawei Kongsheng Zhenzhong Pill: marker compounds, absorption into the serum (rat), and Q-markers identified by UPLC-Q-TOF-MS/MS

Background: The Jiawei Kongsheng Zhenzhong pill (JKZP), a Chinese herbal prescription comprised of eight Chinese crude drugs, has been historically employed to treat neurological and psychological disorders. Nevertheless, the ambiguous material basis severely hindered its progress and application. Purpose: The current study aimed to establish a rapid analytical method for identifying the chemical components of the JKZP aqueous extract and the components absorbed into the rat serum to investigate the quality markers (Q-markers) responsible for the neuroprotective effects of JKZP. Methods: The qualitative detection of the chemical components, prototype components, and metabolites of the aqueous extracts of JKZP, as well as the serum samples of rats that were administered the drug, was performed using the ultra-performance liquid chromatography- quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) technology. This analysis combined information from literature reports and database comparisons. Moreover, the study was conducted to anticipate the potential Q-markers for the neuroprotective effects of JKZP based on the "five principles" of Q-marker determination. Results: A total of 67 compounds and 111 serum components (comprising 33 prototypes and 78 metabolites) were detected and identified. Combining the principles of quality transmission and traceability, compound compatibility environment, component specificity, effectiveness, and measurability, the study predicted that five key compounds, namely, senkyunolide H, danshensu, echinacoside, loganin, and 3,6'-disinapoyl sucrose, may serve as potential pharmacological bases for the neuroprotective effects of JKZP. Conclusion: To summarize, the UPLC-Q-TOF-MS/MS technique can be employed to rapidly and accurately identify compounds in JKZP. Five active compounds have been predicted to be the Q-markers for the neuroprotective effects of JKZP. This discovery serves as a reference for improving quality, advancing further research and development, and utilizing Chinese herbal prescriptions.

Polygala tenuifolia and Acorus tatarinowii in the treatment of Alzheimer's disease: a systematic review and meta-analysis

Background: The complexity of Chinese medicine treatment for Alzheimer's disease (AD) utilizing a multi-herb therapy makes the evidence in current studies insufficient. Herb pairs are the most fundamental form of multi-herb formulae. Among the Chinese herbal formulas for AD treatment, Polygala tenuifolia (PT) and Acorus tatarinowii (AT) appeared as the most commonly used herbal pairs in combination. Objective: The aim of this study is to evaluate the clinical efficacy and safety of the combination of PT and AT in the treatment of AD. Methods: We systematically searched and screened randomized controlled trials of pairing PT and AT for the treatment of AD patients in eight databases with a search deadline of June 26, 2023. Authors, year of publication, title, and basic information such as subject characteristics (age, sex, and race), course of disease, control interventions, dose, and treatment duration were extracted from the screened studies. Primary outcomes assessed included mini-mental state examination (MMSE), activities of daily living (ADL), and AD assessment scale-cognitive subscale (ADAS-cog), while secondary outcomes included efficiency and adverse events. The quality of the included studies was assessed using the Cochrane risk of bias tool. The mean difference with 95% confidence intervals (MD [95% CI]) and risk ratio (RR) was selected as the effect size, and the data were analyzed and evaluated using RevMan 5.4 and Stata 16. Results: A total of sixteen eligible and relevant studies involving 1103 AD participants were included. The combination of PT and AT plus conventional drugs was superior to single conventional drugs in MMSE [MD = 2.57, 95%CI: (1.44, 3.69); p < 0.00001; I 2 = 86%], ADL [MD = -3.19, 95%CI: (-4.29, -2.09); p < 0.00001; I 2 = 0%], and ADAS-cog scores [MD = -2.09, 95%CI: (-3.07, -1.10); p < 0.0001; I 2 = 0%]. The combination of PT and AT plus conventional drugs had a significantly more favorable benefit in clinical effectiveness [RR = 1.27, 95%CI: (1.12, 1.44); p = 0.0002; I 2 = 0%]. Adverse events were not increased with the combination of PT and AT plus conventional drugs compared to conventional drugs [RR = 0.65, 95%CI: (0.35, 1.19); p = 0.16; I 2 = 0%]. The experimental group treated with the combination of PT and AT alone for AD was comparable in MMSE, ADL, and ADAS-cog scores compared with the control group treated with single conventional drugs. Conclusion: Compared to single conventional drugs, the combination of PT and AT may be used as an alternative therapy to improve global cognition and functioning in AD, and the combination of PT and AT as adjunctive therapy appears to produce a better therapeutic response to AD in terms of efficacy without increasing the risk of adverse events. However, the very low to low quality of available evidence limits confidence in the findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023444156.

Exploring the therapeutic potential of natural compounds for Alzheimer's disease: Mechanisms of action and pharmacological properties

Alzheimer's Disease (AD) is a global public health priority characterized by high mortality rates in adults and an increasing prevalence in aging populations worldwide. Despite significant advancements in comprehending the pathogenesis of AD since its initial report in 1907, there remains a lack of effective curative or preventive measures for the disease. In recent years, natural compounds sourced from diverse origins have garnered considerable attention as potential therapeutic agents for AD, owing to their anti-inflammatory, antioxidant, and neuroprotective properties. This review aims to consolidate the therapeutic effects of natural compounds on AD, specifically targeting the reduction of β-amyloid (Aβ) overproduction, anti-apoptosis, autophagy, neuroinflammation, oxidative stress, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Notably, the identified compounds exhibiting these effects predominantly originate from plants. This review provides valuable insights into the potential of natural compounds as a reservoir of novel therapeutic agents for AD, thereby stimulating further research and contributing to the development of efficacious treatments for this devastating disease.

Traditional Chinese medicine for the treatment of Alzheimer's disease: A focus on the microbiota-gut-brain axis

Alzheimer's disease (AD), the most frequent cause of dementia, is a neurodegenerative disorder characterised by a progressive decline in cognitive function that is associated with the formation of amyloid beta plaques and neurofibrillary tangles. Gut microbiota comprises of a complex community of microorganisms residing in the gastrointestinal ecosystem. These microorganisms can participate in gut-brain axis activities, thereby affecting cognitive function and associated behaviours. Increasing evidence has indicated that gut dysbiosis can jeopardise host immune responses and promote inflammation, which may be an initiating factor for the onset and evolution of AD. Traditional Chinese medicine (TCM) is a promising resource which encompasses immense chemical diversity and multiple-target characteristics for the treatment of AD. Many TCMs regulate the gut microbiota during treatment of diseases, indicating that gut microbiota may be an important target for TCM efficacy. In this review, we summarised the role of the microbiota-gut-brain axis in the development of AD and the effects of TCM in treating AD by regulating the gut microbiota. We anticipate that this review will provide novel perspectives and strategies for future AD research and treatments.

3,6'-Disinapoylsucrose alleviates the amyloid precursor protein and lipopolysaccharide induced cognitive dysfunction through upregulation of the TrkB/BDNF pathway

The aim of this study is to explore the effect and mechanism of 3,6'-disinapoylsucrose (DISS) on an Alzheimer's disease (AD) mice model induced by APPswe695 lentivirus (LV) and intraperitoneal injection of lipopolysaccharide (LPS). The results show that DISS improves cognitive ability, decreases the levels of IL-2, IL-6, IL-1β, and TNF-α, reduces the expression of NF-κB p65, and alleviates Aβ deposition and nerve cell damage. DISS can regulate tyrosine kinase B (TrkB)/brain-derived neurotrophic factor (BDNF) signaling in the hippocampus. In summary, DISS can significantly alleviate neuroinflammation, spatial learning and memory disorders in AD model mice.

Gut brain interaction theory reveals gut microbiota mediated neurogenesis and traditional Chinese medicine research strategies

Adult neurogenesis is the process of differentiation of neural stem cells (NSCs) into neurons and glial cells in certain areas of the adult brain. Defects in neurogenesis can lead to neurodegenerative diseases, mental disorders, and other maladies. This process is directionally regulated by transcription factors, the Wnt and Notch pathway, the extracellular matrix, and various growth factors. External factors like stress, physical exercise, diet, medications, etc., affect neurogenesis and the gut microbiota. The gut microbiota may affect NSCs through vagal, immune and chemical pathways, and other pathways. Traditional Chinese medicine (TCM) has been proven to affect NSCs proliferation and differentiation and can regulate the abundance and metabolites produced by intestinal microorganisms. However, the underlying mechanisms by which these factors regulate neurogenesis through the gut microbiota are not fully understood. In this review, we describe the recent evidence on the role of the gut microbiota in neurogenesis. Moreover, we hypothesize on the characteristics of the microbiota-gut-brain axis based on bacterial phyla, including microbiota's metabolites, and neuronal and immune pathways while providing an outlook on TCM's potential effects on adult neurogenesis by regulating gut microbiota.

Effects of Dangshen Yuanzhi Powder on learning ability and gut microflora in rats with memory disorder

ETHNOPHARMACOLOGICAL RELEVANCE

Yuanzhi Powder is a commonly used traditional Chinese medical formulae for its potency in enhancing memory and learning. In clinical practice, Yuanzhi Powder is a classic formula in TCM to treat amnesia of the type "deficiency of Qi, turbid phlegm harasses the head and eyes, and stagnation of phlegm converting into the fire". Our previous study showed that Yuanzhi Power, used together with Codonopsis Radix (Dangshen Yuanzhi Power, DYP), could improve learning and memory ability in animals with memory disorder (MD) and its efficacy is superior or equivalent to that of the Yuanzhi Power.

AIM OF STUDY

This study aimed to explore the regulatory mechanism of DYP through the "bacteria-gut-brain axis".

MATERIALS AND METHODS

The SD rats were divided randomly into control, model, positive, DYP-L, and DYP-H groups. Except for the control group, the rats were intraperitoneally injected with D-Gal (400 mg/kg) and gavaged with aluminum chloride (200 mg/kg) every day for 50 days. The rats in the DYP group were gavaged with DYP (6.67 and 13.34 g/kg, respectively) from the 15th day, once a day. The rats in the positive group were similarly administrated with piracetam (0.5 g/kg). The rats' bodyweight was recorded from the 16th day. The learning and memory ability of animals was tested by Morris water maze. The levels of MCP-1, NF-L, NSE, and TNF-α in serum were determined by Elisa kit, while the histopathology of duodenum and colon tissues was examined by H & E staining. The diversity of intestinal flora was sequenced and analyzed. In order to reveal the role of intestinal flora in DYP treatment of MD, the intestinal flora composition and the correlation analysis of intestinal flora and the above biochemical indexes were investigated. The intestinal flora function and biological metabolic pathways were predicted and analyzed by the KEGG database.

RESULTS

The MD animals' learning and spatial memory ability decreased significantly, compared with the normal group, accompanied by weight increase and intestinal flora disorder. DYP can improve the learning and memory ability of MD animals, and its efficacy may exert through the following ways: (i) callback the abnormal biochemical indexes of MCP-1, NF-L, NSE, and TNF-α; (ii) decreasing the relative ratio of Firmicutes/Bacteroidetes and repairing the pathology of MD animal intestinal mucosa; and (iii) the regulation of DYP on biochemical blood indexes of MD animals was significantly correlated with the regulation of intestinal flora; (iv) DYP rats showed a strong correlation between cognitive ability improvement and bodyweight loss; (v) besides, DYP could also regulate the metabolic pathways of carbohydrate, amino acid, nucleotide, and energy by affecting related biological functions.

CONCLUSIONS

The results supported that DYP can improve MD animals' learning and memory ability by restoring the intestinal flora disorder and callback the abnormal biochemical indexes in serum, closely related to the "bacteria-gut-brain axis".

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.