Polygala tenuifolia: a source for anti-Alzheimer's disease drugs

Polygala tenuifolia willd. Extract alleviates LPS-induced acute lung injury in rats via TLR4/NF-κB pathway and NLRP3 inflammasome suppression

BACKGROUND

Acute lung injury (ALI) has received considerable attention in the field of critical care as it can lead to high mortality rates. Polygala tenuifolia, a traditional Chinese medicine with strong expectorant properties, can be used to treat pneumonia. Owing to the complexity of its composition, the main active ingredient is not yet known. Thus, there is a need to identify its constituent compounds and mechanism of action in the treatment of ALI using advanced technological means.

PURPOSE

We investigated the anti-inflammatory mechanism and constituent compounds with regard to the effect of P. tenuifolia Willd. extract (EPT) in lipopolysaccharide (LPS)-induced ALI in vivo and in vitro.

METHODS

The UHPLC-Q-Exactive Orbitrap MS technology was used to investigate the chemical profile of EPT. Network pharmacology was used to predict the targets and pathways of action of EPT in ALI, and molecular docking was used to validate the binding of polygalacic acid to Toll-like receptor (TLR) 4. The main compounds were determined using LC-MS. A rat model of LPS-induced ALI was established, and THP-1 cells were stimulated with LPS and adenosine triphosphate (ATP) to construct an in vitro model. Pathological changes were observed using hematoxylin and eosin staining, Wright-Giemsa staining, and immunohistochemistry. The expression of inflammatory factors (NE, MPO, Ly-6 G, TNF-α, IL-1β, IL-6, and iNOS) was determined using enzyme-linked immunosorbent assay, real-time fluorescence quantitative polymerase chain reaction, and western blotting. The LPS + ATP-induced inflammation model in THP-1 cells was used to verify the in vivo experimental results.

RESULTS

Ninety-nine compounds were identified or tentatively deduced from EPT. Using network pharmacology, we found that TLR4/NF-κB may be a relevant pathway for the prevention and treatment of ALI by EPT. Polygalacic acid in EPT may be a potential active ingredient. EPT could alleviate LPS-induced histopathological lung damage and reduce the wet/dry lung weight ratio in the rat model of ALI. Moreover, EPT decreased the white blood cell and neutrophil counts in the bronchoalveolar lavage fluid and decreased the expression of genes and proteins of relevant inflammatory factors (NE, MPO, Ly-6 G, TNF-α, IL-1β, IL-6, and iNOS) in lung tissues. It also increased the expression of endothelial-type nitric oxide synthase expression. Western blotting confirmed that EPT may affect TLR4/NF-κB and NLRP3 signaling pathways in vivo. Similar results were obtained in THP-1 cells.

CONCLUSION

EPT reduced the release of inflammatory factors by affecting TLR4/NF-κB and NLRP3 signaling pathways, thereby attenuating the inflammatory response of ALI. Polygalacic acid is the likely compounds responsible for these effects.

Glycyrrhizae radix et rhizoma processing ameliorates adverse reactions of polygalae radix in zebra fish and rabbit models

ETHNOPHARMACOLOGICAL RELEVANCE

Polygala tenuifilia Willd (Polygalaceae), a traditional Chinese medicine, has been used for a long time to treat various illnesses with serious adverse reactions. Glycyrrhizae radix et rhizoma processing is generally used to reduce the adverse reactions.

AIM OF THE STUDY

The aim of this study was to validate the irritation caused by raw Polygalaceae (RPA), to investigate whether processed Polygalaceae (PGA) was less irritating, and to screen and validate irritant properties of virgaureagenin G (polygala acid, PA), 3,6'-disinapoylsucrose (DSS), Tenuifolia (TEN) and polygalaxanthone III (POL), which had pharmacologically active in Polygalaceae. Zebrafish model, Draize test and High-Performance Liquid Chromatography (HPLC) were utilized to achieve the aim.

MATERIALS AND METHODS

Scanning Electron Microscopy (SEM) and optical microscope were used to determine the presence of calcium oxalate needle crystal in RPA and PGA. Zebrafish egg spinning changes and zebrafish embryo behavior were used for irritation validation, irritation comparison and irritant screening. For additional evidence, the Draize test, HE staining of rabbit eyes and ELISA kit were used. Finally, changes in the composition of RPA and PGA were investigated using HPLC.

RESULTS

SEM and optical microscopy revealed no calcium oxalate needle crystals in Polygalaceae. RPA, PGA, PA and DSS were able to accelerate the spinning of zebrafish eggs and the movement of embryos, while TEN and POL were not. RPA, PGA, DSS and PA may cause rabbit eyes to become hyperemic and swollen, resulting in damage to the iris, cornea and conjunctiva and increased levels of interleukin-6 (IL-6) and interleukin-10 (IL-10). Comparatively, the effects caused by PGA were less severe than those caused by RPA. In addition, compared to RPA, PGA had lower levels of DSS and PA.

CONCLUSIONS

RPA, PGA, DSS, and PA were irritating. However, processing and curing could reduce the irritation by reducing the levels of DSS and PA. DSS and PA could be two potential irritants of Polygalaceae.

Tenuifolin improves learning and memory by regulating long-term potentiation and dendritic structure of hippocampal CA1 area in healthy female mice but not male mice

Polygala tenuifolia Wild is an ancient traditional Chinese medicine. Its main component, tenuifolin (TEN), has been proven to improve cognitive impairment caused by neurodegenerative diseases and ovariectomy. However, there was hardly any pharmacological research about TEN and its potential gender differences. Considering the reduction of TEN on learning and memory dysfunction in ovariectomized animals, therefore, we focused on the impact of TEN in different mice genders in the current study. Spontaneous alternation behavior (SAB), light-dark discrimination, and Morris water maze (MWM) tests were used to evaluate the mice's learning and memory abilities. The field excitatory postsynaptic potential (fEPSP) of the hippocampal CA1 region was recorded using an electrophysiological method, and the morphology of the dendritic structure was examined using Golgi staining. In the behavioral experiments, TEN improved the correct rate in female mice in the SAB test, the correct rate in the light-dark discrimination test, and the number of crossing platforms in the MWM test. Additionally, TEN reduced the latency of female mice rather than male mice in light-dark discrimination and MWM tests. Moreover, TEN could significantly increase the slope of fEPSP in hippocampal Schaffer-CA1 and enhance the total length and the number of intersections of dendrites in the hippocampal CA1 area in female mice but not in male mice. Collectively, the results of the current study showed that TEN improved learning and memory by regulating long-term potentiation (LTP) and dendritic structure of hippocampal CA1 area in female mice but not in males. These findings would help to explore the improvement mechanism of TEN on cognition and expand the knowledge of the potential therapeutic value of TEN in the treatment of cognitive impairment.

Preparation, structural characteristics and pharmacological activity of polysaccharides from Polygala tenuifolia: A review

Polygala tenuifolia is a traditional Chinese medicine with a long history of application, with the efficacy of suppressing cough, calming asthma, tranquilizing the mind, and benefiting the intellect. It is classified as a top-quality medicine in Shennong's Classic of Materia Medica. Polysaccharide is an important active ingredient in Polygala tenuifolia, which consists of several monosaccharides, including Ara, Gal, Glc, and so on. In this review, the preparation methods, structural characteristics, and biological activities of polysaccharides from Polygala tenuifolia are summarized, and the problems in the current studies are discussed to support further research, development, and utilization.

Combination of tenuigenin-based Polygala tenuifolia willd. root extract and forsythoside a improved Alzheimer's disease

Tenuigenin is a kind of the main active ingredients in roots of Polygala tenuifolia Willd. (a species in the genus Polygala, family Polygalaceae) and forsythoside A (FA) is one of the main active ingredients of Forsythia suspensa (Thunb.) Vahl. (a species in the genus Forsythia, family Meliaceae). The studies have shown that tenuigenin-based Polygala tenuifolia Willd. extract (YZ) and FA have protective effects on nervous damage. In the study the combination (YF) of YZ and FA showed synergistic neuro-protective effects on PC12 cell model of Alzheimer's disease (AD). YF (2:1) which was made up of 2/3 YZ and 1/3 FA increased cell viability, inhibited AChE expression and activity, alleviated apoptosis and slowed Aβ aggregation, while YF (1:2) which consisted of 1/3 YZ and 2/3 FA depressed inflammation and oxidative stress. There was no obvious synergistic effect of YF on Tau phosphorylation.

HMGR and CHS gene cloning, characterizations and tissue-specific expressions in Polygala tenuifolia Willd

Triterpenoid saponins and flavonoids have several pharmacological activities against P. tenuifolia. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and chalcone synthase (CHS) are the rate-limiting enzymes of triterpenoid saponin and flavonoid biosynthesis, respectively. In this study, HMGR and CHS genes were cloned from P. tenuifolia, and their bioinformatics analyses and tissue-specific expression were investigated. The results showed that the HMGR and CHS genes were successfully cloned, separately named the PtHMGR gene (NCBI accession: MK424118) and PtCHS gene (NCBI accession: MK424117). The PtHMGR gene is 2323 bp long, has an open reading frame (ORF) of 1782 bp, and encods 593 amino acids. The PtCHS gene is 1633 bp long with an ORF of 1170 bp, encoding 389 amino acids. PtHMGR and PtCHS were both hydrophobic, not signal peptides or secreted proteins, containing 10 conserved motifs. PtHMGR and PtCHS separately showed high homology with HMGR and CHS proteins from other species, and their secondary structures mainly included α-helix and random curl. The tertiary structure of PtHMGR was highly similarity to that the template 7ULI in RCSB PDB with 92.0% coverage rate. The HMG-CoA-binding domain of PtHMGR is located at 173-572 amino acid residues, including five bound sites. The tertiary structure of PtCHS showed high consistency with the template 1I86 in RCSB PDB with 100% coverage rate, contained malonyl CoA and 4-coumaroyl-CoA linkers. The expression of PtHMGR and PtCHS is tissue-specific. PtHMGR transcripts were mainly accumulated in roots, followed by leaves, and least in stems, and were significantly positively correlated with the contents of total saponin and tenuifolin. PtCHS was highly expressed in the stems, followed by the leaves, with low expression in the roots. PtCHS transcripts showed a significant positive correlation with total flavonoids content, however, they were significantly negatively correlated with the content of polygalaxanthone III (a type of flavonoids). This study provided insight for further revealing the roles of PtHMGR and PtCHS.

A Herbal Prescription of Insamyangyeongtang as a Therapeutic Agent for Frailty in Elderly: A Narrative Review

Frailty is a major geriatric syndrome with a multifactorial etiology that induces a decline in multiple physiological and psychological functions. In traditional East Asian medicine (TEAM), qi and blood deficiency clinically represent as fatigue, anemia, anorexia, decreased strength after illness, and weakness, commonly interpretated as frailty. An herbal prescription of Insamyangyeongtang (IYT, Ninjin'yoeito in Japanese, Ren-Shen-Yang-Rong-Tang in Chinese) tonifies qi and blood and has the potential to treat multiple targets caused by qi and blood deficiency. As the population ages and frailty increases, there is an increase in the potential effectiveness of IYT in frailty. This study reviewed relevant clinical trials to provide an updated view on the effect of IYT on frailty. IYT has therapeutic effects on frailty associated with chronic respiratory diseases (e.g., chronic obstructive pulmonary disease) and cognitive impairments (e.g., Alzheimer's disease) and improves respiratory symptoms and cognition. IYT also has therapeutic effects on weight gain, muscle mass, and strength, and improves nutritional status in frail elderly individuals who have decreased muscle mass and strength, loss of appetite, and weight loss. The same effect has been shown in frailty in elderly individuals with rehabilitation treatment and chronic diseases. IYT also improves frailty associated with symptoms such as intractable dizziness and genitourinary symptoms. The beneficial effects of IYT in several diseases could be important for medication replacement, reduction, and prevention of polypharmacy. Based on the results of this review, we suggest that IYT has the potential to be a therapeutic agent against frailty.

Polygalacic acid attenuates cognitive impairment by regulating inflammation through PPARγ/NF-κB signaling pathway

AIMS

We aimed to explore the role and molecular mechanism of polygalacic acid (PA) extracted from traditional Chinese medicine Polygala tenuifolia in the treatment of Alzheimer's disease (AD).

METHODS

The network pharmacology analysis was used to predict the potential targets and pathways of PA. Molecular docking was applied to analyze the combination between PA and core targets. Aβ42 oligomer-induced AD mice model and microglia were used to detect the effect of PA on the release of pro-inflammatory mediators and its further mechanism. In addition, a co-culture system of microglia and neuronal cells was constructed to assess the effect of PA on activating microglia-mediated neuronal apoptosis.

RESULTS

We predict that PA might regulate inflammation by targeting PPARγ-mediated pathways by using network pharmacology. In vivo study, PA could attenuate cognitive deficits and inhibit the expression levels of inflammation-related factors. In vitro study, PA can also decrease the production of activated microglia-mediated inflammatory cytokines and reduce the apoptosis of N2a neuronal cells. PPARγ inhibitor GW9662 inversed the neuroprotective effect of PA. Both in vivo and in vitro studies showed PA might attenuate the inflammation through the PPARγ/NF-κB pathway.

CONCLUSIONS

PA is expected to provide a valuable candidate for new drug development for AD in the future.

Tenuigenin activates the IRS1/Akt/mTOR signaling by blocking PTPN1 to inhibit autophagy and improve locomotor recovery in spinal cord injury

ETHNOPHARMACOLOGICAL RELEVANCE

Tenuigenin (TEN) is a main pharmacologically active component of Polygala tenuifolia Willd. (Polygalaceae), which has shown neuroprotective functions in Alzheimer's disease. Moreover, TEN also demonstrated an anti-oxidative impact in an in vitro model of Parkinson's disease, reducing damage and loss of dopaminergic neurons.

AIM

This work focuses on the impact of TEN on locomotor recovery following spinal cord injury (SCI) and underpinning molecules involved.

METHODS

A rat model of SCI was generated, and the rats were treated with TEN, oe-PTPN1 (PTP non-receptor type 1), a protein kinase B (Akt)/mammalian target of rapamycin (mTOR) antagonist LY294002, or an autophagy inhibitor 3-methyladenine (3-MA). Subsequently, locomotor function was detected. Pathological changes and neuronal activity in the spinal cord tissues were analyzed by hematoxylin and eosin staining, Nissl staining, and TUNEL assays. Protein expression of Beclin-1 and microtubule associated protein 1 light chain 3 beta (LC3B)-II/LC3B-I, PTPN1, IRS1, mTOR, and phosphorylated Akt (p-Akt) was analyzed by western blot assays. The LC3B expression was further examined by immunofluorescence staining.

RESULTS

Treatment with TEN restored the locomotor function of SCI rats, reduced the cavity area and cell apoptosis, upregulated growth-associated protein 43 and neurofilament 200, and decreased the Beclin-1 and LC3B-II/LC3B-I levels in the spinal cord. TEN suppressed PTPN1 protein level, while PTPN1 suppressed IRS1 protein to reduce the p-Akt and mTOR levels. Either PTPN1 overexpression or LY294002 treatment blocked the promoting effect of TEN on SCI recovery. However, treatment with 3-MA suppressed autophagy, which consequently rescued the locomotor function and reduced neuron loss induced by PTPN1.

CONCLUSION

This study demonstrates that TEN suppresses autophagy to promote function recovery in SCI rats by blocking PTPN1 and rescuing the IRS1/Akt/mTOR signaling.

Study on the active ingredients of Shenghui decoction inhibiting acetylcholinesterase based on molecular docking and molecular dynamics simulation

We aim to investigate the mechanism and effective components of Shenghui decoction (SHD), which has been shown to inhibit acetylcholinesterase (AChE) through molecular docking (MD) and molecular dynamics simulation (MDS). The effective ingredients in SHD were collected through the TCMSP database and literature review. All components were docked with AChE using CDOCKER. Receptor ligand interaction analysis was performed for the optimal ligand. Two simulation models (model I and II) containing AChE and acetylcholine (ACh) were constructed, in which model II contained the best-docked ligand. Perform 90ns MDS on 2 models. After the simulation, the distance between ACh and AChE peripheral active sites were calculated in both models. The root mean square deviation (RMSD) curve of ligand and receptor, the radius of gyration (Rog) of the receptor, the distance between ligand center and binding site center, and the binding energy of ligand and receptor were calculated in model II. 98 ingredients of SHD were collected, and the best ligand was Tumulosic acid. The residues that form conventional hydrogen bonds between AChE and Tumulosic acid include Tyr132 and Glu201. MDS revealed that ACh could bind to AChE active site in model I. In model II, ACh cannot bind to the binding cavity because the ligand occupies the active site. The RMSD of AChE and Tumulosic acid tends to be stable, the Rog curve of AChE is relatively stable, and the distance between ligand and binding cavity does not fluctuate greatly, indicating that the structure of receptor and ligand is relatively stable. The binding energy of AChE and Tumulosic acid was -24.14 ± 2.46 kcal/mol. SHD contains many effective ingredients that may inhibit AChE activity. Tumulosic acid can occupy the binding site to prevent ACh from entering the chemical domain, thus exerting AChE inhibitory effect.

Tenuigenin promotes non-rapid eye movement sleep via the GABAA receptor and exerts somnogenic effect in a MPTP mouse model of Parkinson's disease

Sleep disturbances are commonly non-motor symptoms in Parkinson's diseases (PD). However, standard dopamine replacement therapies for the treatment of motor symptoms often prove inadequate in combating sleep disturbances. Previous studies conducted by our research group have reported the neuroprotective effects of tenuigenin, a natural extract from Polygala tenuifolia root, which has been traditionally employed in treating insomnia. The objective of this study was to investigate the potential of tenuigenin in modulating sleep-wake behaviors and elucidate the underlying mechanisms. We employed EEG/EMG recordings to evaluate the impact of tenuigenin on sleep-wake profiles. Furthermore, we utilized c-Fos immunostaining, whole-cell patch clamping and local field potentials (LFP) recording to explore the mechanisms involved in sleep-promoting effects of tenuigenin. Additionally, we examined the effects of tenuigenin on sleep-promoting in MPTP PD mice. Here, we found tenuigenin demonstrated a significant increase in NREM sleep and a reduction in sleep latency in mice, without altering the EEG power density. Moreover, tenuigenin increased c-Fos expression in the ventrolateral preoptic area (VLPO) and stimulated sleep-promoting neurons in VLPO. The sleep-promoting effects of tenuigenin were abolished when mice were pretreated with flumazenil, an antagonist at the benzodiazepine site of the GABAA receptor. Furthermore, tenuigenin was found to ameliorate sleep disturbances in MPTP-induced mice. The results suggesting that tenuigenin facilitated a type of NREM sleep comparable to physiological NREM sleep through interaction with the GABAA receptor. Additionally, tenuigenin demonstrated improvements in sleep disturbances in MPTP-induced PD mice, suggesting its potential as a sleep-promoting substance, particularly for PD patients experiencing sleep disturbances.

Genome assembly of Polygala tenuifolia provides insights into its karyotype evolution and triterpenoid saponin biosynthesis

Polygala tenuifolia is a perennial medicinal plant that has been widely used in traditional Chinese medicine for treating mental diseases. However, the lack of genomic resources limits the insight into its evolutionary and biological characterization. In the present work, we reported the P. tenuifolia genome, the first genome assembly of the Polygalaceae family. We sequenced and assembled this genome by a combination of Illumnina, PacBio HiFi, and Hi-C mapping. The assembly includes 19 pseudochromosomes covering ~92.68% of the assembled genome (~769.62 Mb). There are 36 463 protein-coding genes annotated in this genome. Detailed comparative genome analysis revealed that P. tenuifolia experienced two rounds of whole genome duplication that occurred ~39-44 and ~18-20 million years ago, respectively. Accordingly, we systematically reconstructed ancestral chromosomes of P. tenuifolia and inferred its chromosome evolution trajectories from the common ancestor of core eudicots to the present species. Based on the transcriptomics data, enzyme genes and transcription factors involved in the synthesis of triterpenoid saponin in P. tenuifolia were identified. Further analysis demonstrated that whole-genome duplications and tandem duplications play critical roles in the expansion of P450 and UGT gene families, which contributed to the synthesis of triterpenoid saponins. The genome and transcriptome data will not only provide valuable resources for comparative and functional genomic researches on Polygalaceae, but also shed light on the synthesis of triterpenoid saponin.

Mechanisms of ferroptosis in Alzheimer's disease and therapeutic effects of natural plant products: A review

Neurodegenerative diseases, such as Alzheimer's disease (AD), are characterized by massive loss of specific neurons. It is a progressive disabling, severe and fatal complex disease. Due to its complex pathogenesis and limitations of clinical treatment strategies, it poses a serious medical challenge and medical burden worldwide. The pathogenesis of AD is not clear, and its potential biological mechanisms include aggregation of soluble amyloid to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFT), neuroinflammation, ferroptosis, oxidative stress and metal ion disorders. Among them, ferroptosis is a newly discovered programmed cell death induced by iron-dependent lipid peroxidation and reactive oxygen species. Recent studies have shown that ferroptosis is closely related to AD, but the mechanism remains unclear. It may be induced by iron metabolism, amino acid metabolism and lipid metabolism affecting the accumulation of iron ions. Some iron chelating agents (deferoxamine, deferiprone), chloroiodohydroxyquine and its derivatives, antioxidants (vitamin E, lipoic acid, selenium), chloroiodohydroxyquine and its derivatives Fer-1, tet, etc. have been shown in animal studies to be effective in AD and exert neuroprotective effects. This review summarizes the mechanism of ferroptosis in AD and the regulation of natural plant products on ferroptosis in AD, in order to provide reference information for future research on the development of ferroptosis inhibitors.

Tenuifolin ameliorates the sleep deprivation-induced cognitive deficits

Tenuifolin (TEN), a natural neuroprotective compound obtained from the Polygala tenuifolia Willd plant, has improved cognitive symptoms. However, the impact of TEN on memory impairments caused by sleep deprivation (SD) is unclear. Accordingly, the objective of this study was to investigate the mechanisms behind the preventative benefits of TEN on cognitive impairment caused by SD. TEN (10 and 20 mg/kg) and Huperzine A (0.1 mg/kg) were given to mice through oral gavage for 28 days during the SD process. The results indicate that TEN administrations improve short- and long-term memory impairments caused by SD in the Y-maze, object identification, and step-through tests. Moreover, TEN stimulated the generation of anti-inflammatory cytokines (interleukin-10), lowered the production of pro-inflammatory cytokines (interleukin-1β, interleukin-6, and interleukin-18), and activated microglia, improving antioxidant status in the hippocampus. TEN treatments significantly boosted the expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 while considerably decreasing the expression of NOD-like receptor thermal protein domain associated protein 3 and caspase-1 p20. Additionally, TEN restored the downregulation of the brain-derived neurotrophic factor signaling cascade and the impaired hippocampal neurogenesis induced by SD. When considered collectively, our data suggest that TEN is a potentially effective neuroprotective agent for cognition dysfunction.

Synthesis, Characterization and Biological Evaluation of Benzothiazole-Isoquinoline Derivative

Currently, no suitable clinical drugs are available for patients with neurodegenerative diseases complicated by depression. Based on a fusion technique to create effective multi-target-directed ligands (MTDLs), we synthesized a series of (R)-N-(benzo[d]thiazol-2-yl)-2-(1-phenyl-3,4-dihydroisoquinolin-2(1H)-yl) acetamides with substituted benzothiazoles and (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline. All compounds were tested for their inhibitory potency against monoamine oxidase (MAO) and cholinesterase (ChE) by in vitro enzyme activity assays, and further tested for their specific inhibitory potency against monoamine oxidase B (MAO-B) and butyrylcholinesterase (BuChE). Among them, six compounds (4b-4d, 4f, 4g and 4i) displayed excellent activity. The classical antidepressant forced swim test (FST) was used to verify the in vitro results, revealing that six compounds reduced the immobility time significantly, especially compound 4g. The cytotoxicity of the compounds was assessed by the MTT method and Acridine Orange (AO) staining, with cell viability found to be above 90% at effective compound concentrations, and not toxic to L929 cells reversibility, kinetics and molecular docking studies were also performed using compound 4g, which showed the highest MAO-B and BuChE inhibitory activities. The results of these studies showed that compound 4g binds to the primary interaction sites of both enzymes and has good blood-brain barrier (BBB) penetration. This study provides new strategies for future research on neurodegenerative diseases complicated by depression.

Qualitative and quantitative analysis of the bioactive components of "ginseng-polygala" drug pair against PC12 cell injury based on UHPLC-QTOF-MS and HPLC

Aβ_25-35-induced PC12 cells were used as the in vitro injury model to evaluate the effects on PC12 cells after intervention with the "ginseng-polygala" drug pair. The results showed that the drug pair could significantly increase cell activity and reduce the level of reactive oxygen species and the concentration of inflammatory factors to improve the Alzheimer's disease treatment process. Furthermore, to rapidly identify and classify complicated bioactive components of the drug pair, a liquid chromatography with quadrupole time-of-flight mass spectrometry method combined with a molecular network strategy was established. With this strategy, 40 constituents were preliminarily identified and a database of the compounds was successfully established. Among them, 12 compounds of different categories were accurately identified by comparison with reference substances. The content of the aforementioned active components was simultaneously determined by HPLC to control the quality of compatible medicinal materials, and the verification results of the analytical method met the content determination requirements. The results revealed that after compatibility, the content change of the components is not the simple addition of quantity but the comprehensive effect of the two medicines. In conclusion, this study could provide a generally applicable strategy for pharmacological activity, structural identification, and content determination in traditional Chinese medicine and its compatibility.

Protective effects of isofraxidin against scopolamine-induced cognitive and memory impairments in mice involve modulation of the BDNF-CREB-ERK signaling pathway

BACKGROUND

Isofraxidin is a coumarin compound mainly isolated from several traditional and functional edible plants beneficial for neurodegenerative diseases, including Sarcandra glabra and Apium graveolens, and Siberian Ginseng.

OBJECTIVE

This study aimed to assess effects of isofraxidin against memory impairments and cognition deficits in a scopolamine-induced mouse model.

MATERIALS & METHODS

Animals were randomly divided into 6 groups, control, vehicle, donepezil (10 mg/kg, p.o.), and isofraxidin (3, 10, and 30 mg/kg, p.o.). Isofraxidin or donepezil was administered for 44 days, once per day. The scopolamine insults (1 mg/kg, i.p.) was given from the 21st day, once per day. Morris water maze test and Y-maze test were used for the behavioral test. After that, brain samples were collected for analysis.

RESULTS

Firstly, isofraxidin significantly improved scopolamine-induced behavioral impairments and cognition deficits in Morris water maze and Y-maze test. Then, isofraxidin facilitated cholinergic activity via inhibiting acetylcholinesterase (AChE) activity. Besides, isofraxidin decreased lipid peroxidation level but enhanced levels of glutathione, glutathione peroxidase, and superoxide dismutase. Moreover, isofraxidin suppressed the expression of inflammatory mediators and cytokines. Further investigations showed that isofraxidin up-regulated expression of brain-derived neurotrophic factor (BDNF), and promoted phosphorylation of tropomyosin-related kinase B (TrkB), cyclic AMP-response element-binding protein (CREB), and extracellular signal-regulated kinase (ERK).

DISCUSSION & CONCLUSIONS

These results suggested that isofraxidin ameliorated scopolamine-induced cognitive and memory impairments, possibly through regulating AChE activity, suppressing oxidative stress and inflammatory response, and modulating BDNF-CREB-ERK pathways.

Chemical Constituents of the Roots of Polygala tenuifolia and Their Anti-Inflammatory Effects

Increasing scientific evidence has demonstrated that the roots of Polygala tenuifolia Willd. have pharmacological effects related to anti-inflammation. Therefore, the aim of this study is to investigate the chemical constituents from P. tenuifolia roots as anti-inflammatory drug candidates. In the present work, twenty-three compounds were isolated from P. tenuifolia roots, including three saponins (1-3), ten phenylpropanoid sucrose esters (4-12), one benzoic acid sugar ester derivative (13), four xanthones (14-17), two hydroxy benzophenone derivatives (18 and 19), two phenolic derivatives (20 and 21), and two ionones (22 and 23). All isolates were tested for their inhibitory effects of LPS-stimulated NO and PGE₂ production in RAW 264.7 macrophages. Among these, 3-O-(3,4,5-trimethoxy-cinnamoyl),6'-O-(p-methoxybenzoyl) sucrose ester (TCMB; 11) together with compounds 3 and 21 exhibited significant inhibitory effects on NO production, while TCMB and compounds 17, 19, and 21 showed strong inhibitory effects on PGE₂ production. Specifically, TCMB (11) downregulated the protein levels of iNOS and COX-2 in LPS-induced RAW 264.7 macrophages. In addition, TCMB (11) dose-dependently diminished the relative mRNA expression levels of iNOS, PGE₂, and proinflammatory cytokines (TNF-α, IL-1β, and IL-6). A molecular docking study showed that TCMB (11) has strong binding affinities with iNOS and COX-2.

The mechanism of ferroptosis regulating oxidative stress in ischemic stroke and the regulation mechanism of natural pharmacological active components

Cerebrovascular diseases, such as ischemic stroke, pose serious medical challenges worldwide due to their high morbidity and mortality and limitations in clinical treatment strategies. Studies have shown that reactive oxygen species (ROS)-mediated inflammation, excitotoxicity, and programmed cell death of each neurovascular unit during post-stroke hypoxia and reperfusion play an important role in the pathological cascade. Ferroptosis, a programmed cell death characterized by iron-regulated accumulation of lipid peroxidation, is caused by abnormal metabolism of lipids, glutathione (GSH), and iron, and can accelerate acute central nervous system injury. Recent studies have gradually uncovered the pathological process of ferroptosis in the neurovascular unit of acute stroke. Some drugs such as iron chelators, ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1) can protect nerves after neurovascular unit injury in acute stroke by inhibiting ferroptosis. In addition, combined with our previous studies on ferroptosis mediated by natural compounds in ischemic stroke, this review summarized the progress in the regulation mechanism of natural chemical components and herbal chemical components on ferroptosis in recent years, in order to provide reference information for future research on ferroptosis and lead compounds for the development of ferroptosis inhibitors.

Senegenin alleviates Aβ1-42 induced cell damage through triggering mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Senegenin (SEN), an active compound extracted from the traditional Chinese herb Polygala tenuifolia Willd. (a species in the genus Polygala, family Polygalaceae), could nourish neurons and resist neuronal damage in mouse models of Alzheimer's disease (AD). Amyloid-β (Aβ) depositions in neuronal cells may cause pathological changes such as oxidative stress which one return could cause severe damage to mitochondria in AD patients or animal models. Mitophagy is an important mechanism to selectively remove damaged mitochondria. In neurons, this process is mainly mediated by PTEN-induced putative kinase 1 (PINK1)/Parkin pathway. Previous studies have shown that SEN could reduce mitochondrial damage and inhibit apoptosis in neurons. Therefore, this study speculated that SEN might activate mitophagy to clear damaged mitochondria, thereby mitigating Aβ-induced cell damage in neuronal cells.

AIM OF THE STUDY

This study aimed to determine the effects of SEN on Aβ-induced cell damage, and further to explore whether SEN could induce mitophagy. Moreover, the regulatory role of mitophagy in the neuroptrotective effect of SEN would be elucidated.

MATERIALS AND METHODS

This study established an in vitro cell damage model using Aβ_1-42 to treat mouse hippocampal neuron HT22 cells. The effects of SEN on cell damage were determined by MTT assay and lactate dehydrogenase (LDH) release assay. Reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by Cytation™5 cell imaging microplate detection system. The apoptotic rate was analyzed by flow cytometry. The effects of SEN on mitophagy were detected by transmission electron microscope, immunofluorescence and immunoblotting.

RESULTS

Firstly, HT22 cells were treated with 30 μM Aβ_1-42 for 24 h to establish the damage model. It was found that 30 μM Aβ_1-42 caused neuronal damages as evidenced by reduced cell viability, increased LDH release and ROS, collapsed MMP and elevated apoptosis. Secondly, Aβ_1-42-incubated cells were treated with 10, 20, 40 and 60 μM SEN for 24 h. SEN significantly reduced the damage of Aβ_1-42-incubated cells as shown by recovered cell viability and MMP, reduced apoptosis and ROS. Notably, SEN induced the formation of mitophagosomes and mitolysosomes, and elevated the conversion of LC3 I to LC3 II. Moreover, SEN down-regulated the expression of p62, promoted the accumulation of full-length PINK1 and the translocation of Parkin to mitochondria, decreased the expression of mitochondrial matrix protein HSP60, thus activating the PINK1/Parkin-mediated mitophagy. However, when cells were pretreated with 5 μM CsA (Cyclosporine A, a mitophagy inhibitor) for 2 h and then co-treated with 20 and 40 μM SEN for 24 h, the protective effects of SEN were compromised.

CONCLUSIONS

The present study demonstrated that SEN could alleviate Aβ_1-42-induced cell damage through PINK1/Parkin-mediated mitophagy. Our findings justify the traditional use of P. tenuifolia in China with anti-aging or anti-neurodegenerative effects.

Senegenin Rescues PC12 Cells with Oxidative Damage Through Inhibition of Ferroptosis

Oxidative stress is one of the pathological mechanisms of Alzheimer's disease (AD), and ferroptosis has been determined to be involved in neurodegenerative diseases such as AD. Senegenin (Sen) prevents oxidative damage in nerve cells via a mechanism that may be highly related to ferroptosis. However, the mechanism of ferroptosis pathway involvement in AD is unclear. In this study, we established a model of PC12 cytotoxic injury induced by Aβ_25-35, and we detected the level of oxidative damage, MMP, and ferroptosis-related protein expression. The results showed that, compared with control group, the level of ROS increased, GPX activities decreased, and MDA levels increased in Aβ_25-35 group. Aβ_25-35 could induce mitochondrial depolarization in PC12 cells and Fer-1 could not reverse this damage. WB revealed that Aβ_25-35 group had increased ACSL4 and PEBP1 proteins, and decreased GPX4 protein. After adding Sen in the model, the level of oxidative damage was reduced, and mitochondrial depolarization was reversed compared with Aβ_25-35 group. WB suggested that the expression of ACSL4 and PEBP1 proteins decreased, and the expression of GPX4 protein increased by Sen treatment. In conclusion, we found that Sen exhibits strong neuroprotective activity against Aβ_25-35 induced oxidative damage and lipid metabolic associated with ferroptosis. Inhibiting nerve cell ferroptosis might facilitate the future development of strategies to AD.

Signal pathways in the treatment of Alzheimer's disease with traditional Chinese medicine

AIM OF THE REVIEW

This study aimed to reveal the classical signal pathways and important potential targets of traditional Chinese medicine (TCM) for treating Alzheimer's disease (AD), and provide support for further investigation on TCM and its active ingredients.

MATERIALS AND METHODS

Literature survey was conducted using PubMed, Web of Science, Google Scholar, CNKI, and other databases, with "Alzheimer's disease," "traditional Chinese medicine," "medicinal herb," "Chinese herb," and "natural plant" as the primary keywords.

RESULTS

TCM could modulate signal pathways related to AD pathological progression, including NF-κB, Nrf2, JAK/STAT, ubiquitin-proteasome pathway, autophagy-lysosome pathway-related AMPK/mTOR, GSK-3/mTOR, and PI3K/Akt/mTOR, as well as SIRT1 and PPARα pathway. It could regulate crosstalk between pathways through a multitarget, thus maintaining chronic inflammatory interaction balance, inhibiting oxidative stress damage, regulating ubiquitin-proteasome system function, modulating autophagy, and eventually improving cognitive impairment in patients with AD.

CONCLUSION

TCM could be multilevel, multitargeted, and multifaceted to prevent and treat AD. In-depth research on the prevention and treatment of AD with TCM could provide new ideas for exploring the pathogenesis of AD and developing new anti-AD drugs.

Active Compounds and Targets of Yuanzhi Powder in Treating Alzheimer's Disease and Its Relationship with Immune Infiltration Based on HPLC Fingerprint and Network Pharmacology

Background

Yuanzhi powder (YZP) has been extensively investigated as a natural prescription with therapeutic benefits for Alzheimer's disease (AD). However, its active compounds and underlying immune mechanism for treating AD are still unclear. This study aimed to investigate the immune mechanism of YZP against AD through high-performance liquid chromatography (HPLC)-based network pharmacology and gene chip technology.

Methods

Active components of YZP were obtained from HPLC and public databases. Subsequently, GSE5281, GSE28146, GSE29378, and GSE97760 from the Gene Expression Omnibus (GEO) database were downloaded to extract AD difference genes (DEGs). The active components-targets network and protein interaction network were then constructed by Cytoscape. The biological processes and signaling pathways, which implicate the targets of YZP for AD, were analyzed using the ClueGo Cytoscape plug-in. Molecular docking experiments were performed to verify the affinity of targets and ligands. Ultimately, the link between the hub genes and immune cell infiltration was assessed via CIBERSORT.

Results

83 YZP active compounds and 641 DEGs associated with AD, including quercetin, berberine, 3,6′-disinapoylsucrose, coptisine, and palmatine, were evaluated. We showed that FOS, CCL2, and GJA1 were the core targets and that the gap junction is an essential signaling pathway in YZP for AD. Furthermore, the AD group had a higher infiltration level of naïve B cells and resting CD4 memory T cells, as determined by the CIBERSORT. Notably, the immune cells-targets network demonstrates that GJA1 and GRM1 are intimately related to naïve B cells and plasma cells.

Conclusions

YZP may help treat AD by targeting proteins with key active compounds to regulate naïve B cells and plasma cells. Our results demonstrate a new immune mechanism for treating AD with YZP.

Metabolomics-Based Pharmacodynamic Analysis of Zhuang Yao Shuang Lu Tong Nao Granules in a Rat Model of Ischemic Cerebral Infarction

This study used a metabolomic approach to reveal changes in the levels of metabolic biomarkers and related metabolic pathways before and after Zhuang Yao Shuang Lu Tong Nao granule (YHT) treatment in rats with cerebral ischemia. The neurological deficit scores were significantly higher in the MCAO_R group than in the NC group, indicating that the mice had significantly impaired motor functions. The YHT group had significantly lower scores than the MCAO_R group, suggesting that YHT significantly improved motor function in rats. TTC staining of the brain tissue revealed that YHT significantly reduced the area of cerebral infarction in the treated rats. The MCAO_R group was better separated from the NC rent, sham, and YHT groups via metabolomic PCA. Moreover, there were significant differences in the differential metabolites between the MACO_R and YHT groups. Eighteen common differential metabolites were detected between the MACO_R and NC groups, MACO_R and sham groups, and MACO_R and YHT groups, indicating that YHT significantly increased the levels of various metabolites in the serum of cerebral ischemic stroke (CIS) rats. Moreover, a total of 23 metabolic pathways were obtained. We identified 11 metabolic pathways with the most significant effects in the bubble plots. In conclusion, from a systems biology perspective, this metabolomics-based study showed that YHT could be used to treat ischemic stroke by modulating changes in endogenous metabolites.

Preventing Dementia Using Saffron, The Kampo Medicine, Kamiuntanto, and Their Combination, Kamiuntantokabankoka

The objective of this review is to evaluate the anti-dementia activities of saffron and its combination with Kampo medicine. The Kampo formula Kamiuntanto composed of 13 crude drugs is well known for its anti-dementia activity. A significant increase in choline acetyltransferase activity and mRNA levels were observed. Polygala radix was identified as the most essential component drug in Kamiuntanto, probably due to the saponins, tenuifolin, and sinapinic acid. Ginseng was also identified as an essential Kamiuntanto component in terms of its synergistic functions with Polygala radix. Saffron, which was recommended in the Bencao Gangmu for memory and dementia, and is used as an anti-spasmodic, anti-catarrhal, and sedative herbal drug. Saffron and its major constituent, crocin were shown to enhance learning-memory, non-rapid eye movement (rem) sleep, and inhibit depression and neuronal cell death due to strong anti-oxidant and anti-inflammation activities. In addition based on the epidemiological studies such as the treatment of sleeping disorders and the clinical trials of saffron for Alzheimer patients, we demonstrated the indirect and direct anti-dementia activities of crocin and saffron.

Polygala saponins inhibit NLRP3 inflammasome-mediated neuroinflammation via SHP-2-Mediated mitophagy

Activation of the NLRP3 inflammasome and its mediated neuroinflammation are implicated in neurodegenerative diseases, while mitophagy negatively regulates NLRP3 inflammasome activation. SHP-2, a protein-tyrosine phosphatase, is critical for NLRP3 inflammasome regulation and inflammatory responses. In this study, we investigated whether triterpenoid saponins in Radix Polygalae inhibit the NLRP3 inflammasome via mitophagy induction. First, we isolated the active fraction (polygala saponins (PSS)) and identified 17 saponins by ultra-performance liquid chromatography coupled with diode-array detection and tandem quadrupole time-of-flight mass spectrometry (UHPLC-DAD-Q/TOF-MS). In microglial BV-2 cells, PSS induced mitophagy as evidenced by increased co-localization of LC3 and mitochondria, as well as an increased number of autophagic vacuoles surrounding the mitochondria. Furthermore, the mechanistic study found that PSS activated the AMPK/mTOR and PINK1/parkin signaling pathways via the upregulation of SHP-2. In Aβ(1-42)-, A53T-α-synuclein-, or Q74-induced BV-2 cells, PSS significantly inhibited NLRP3 inflammasome activation, which was attenuated by bafilomycin A1 (an autophagy inhibitor) and SHP099 (an SHP-2 inhibitor). In addition, the co-localization of LC3 and ASC revealed that PSS promoted the autophagic degradation of the NLRP3 inflammasome. Moreover, PSS decreased apoptosis in conditioned medium-induced PC-12 cells. In APP/PS1 mice, PSS improved cognitive function, ameliorated Aβ pathology, and inhibited neuronal death. Collectively, the present study, for the first time, shows that PSS inhibit the NLRP3 inflammasome via SHP-2-mediated mitophagy in vitro and in vivo, which strongly suggests the therapeutic potential of PSS in various neurodegenerative diseases.

PTP70-2, a novel polysaccharide from Polygala tenuifolia, prevents neuroinflammation and protects neurons by suppressing the TLR4-mediated MyD88/NF-κB signaling pathway

PTP70-2, a novel polysaccharide isolated from Polygala tenuifolia in our previous publication, exhibits potential anti-inflammatory effects. Here, we investigate the mechanisms underlying these effects and the neuroprotective activity of PTP70-2 in lipopolysaccharide (LPS)-damaged BV2 microglial cells and neuroinflammation-injured primary cortical neurons. The results suggest that PTP70-2 dramatically reduces the LPS-stimulated inflammatory cytokines overexpression, as well as down-regulates the levels of TLR4-, MyD88-, and NF-κB-related proteins. The effect of PTP70-2 in down-regulation of proinflammatory cytokines and downstream proteins implicated in MyD88 and NF-κB signaling is related to the TLR4 pathway. Furthermore, this effect is enhanced by the co-incubation of BV2 cells with PTP70-2 and TAK242, a TLR4 inhibitor, before exposure to LPS. Importantly, PTP70-2 prevents neuroinflammation-induced neurotoxicity by mitigating ROS overproduction and MMP dissipation. Overall, the PTP70-2's anti-neuroinflammation and neuroprotection are involved to the modulation of the TLR4-mediated MyD88/NF-κB signaling pathway.

Chemical constituents from the aerial part of Polygala tenuifolia

Three new compounds, polygalapyrone A (1), tenuiside G (2) and polygalapyrrole A (3), together with two known compounds (4-5) were isolated by silica gel, ODS and preparative HPLC from the aerial part of Polygala tenuifolia. Their structures were elucidated by spectrum analysis and compared with findings from the literature. The anti-inflammatory effects of those compounds were investigated in vitro.

A comprehensive review on medicinal herbs and novel formulations for the prevention of Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases reported in the aging population across the globe. About 46.8 million people are reported to have dementia, and AD is mainly responsible for dementia in aged people. Alzheimer's disease (AD) is thought to occur due to the accumulation of β-amyloid (Aβ) in the neocortex portion of the brain, nitric oxide mediated dysfunctioning of blood-brain barrier, reduced activity of serine racemase enzyme, cell cycle disturbances, damage of N-methyl-D-aspartate (NMDA) receptors and glutamatergic neurotransmission. Modern treatment methods target the pathways responsible for the disease. To date, solely symptomatic treatments exist for this disease, all making an attempt to counterbalance the neurotransmitter disturbance. Treatments able to prevent or at least effectively modifying the course of AD, referred to as 'disease-modifying' drugs, are still under extensive research. Effective treatments entail a better indulgence of the herbal bioactives by novel drug delivery systems. The herbal bioactive administered by novel drug delivery systems have proved beneficial in treating this disease. This review provides detailed information about the role of medicinal plants and their formulations in treating Alzheimer disease which will be highly beneficial for the researchers working in this area.

A review of nardosinone for pharmacological activities

Nardostachys jatamansi is a natural medicinal plant that is widely used in Asia for the treatment of various neurological and cardiac diseases, and nardosinone is the main active ingredient of N. jatamansi, which has the potential to treat a variety of diseases. Herein, we summarize the reported chemical structure, pharmacokinetics and pharmacological potential of nardosinone, and point out areas for further research. We obtained studies that were related to the chemical structure and pharmacological activities of nardosinone from several databases. Previous studies have shown that nardosinone has anti-inflammatory effects, anti-hypertrophic effect in cardiomyocytes, enhances activity of the nerve growth factor and promotes neural stem cells to proliferate and differentiate. However, the molecular mechanism of how nardosinone promotes proliferation and differentiation of neural stem cells, and its role in resisting cardiomyocyte hypertrophy remains unclear and needs to be further studied. Overall, nardosinone has the potential to treat bacterial infections, periodontitis, cardiac diseases, neurodegenerative diseases and cancer. However, the gaps found in the literature is the lack of more comprehensive information regarding the pharmacokinetics and toxicology of nardosinone.

Combination of urine and faeces metabolomics to reveal the intervention mechanism of Polygala tenuifolia compatibility with Magnolia officinalis on gastrointestinal motility disorders

OBJECTIVES

To explore the intervention mechanism of combining Polygala tenuifolia (PT) with Magnolia officinalis (MO) on gastrointestinal motility disorders caused by PT.

METHODS

Urine and faeces of rats were collected; the effects of PT and MO on the gastric emptying and small intestine advancing rates in mice were analysed via ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) to determine the potential metabolites. Changes in the metabolic profiles of the urine and faeces were revealed by untargeted metabolomics, followed by multivariate statistical analysis. The integration of urine and faeces was applied to reveal the intervention mechanism of PT-MO on PT-induced disorders.

KEY FINDINGS

PT + MO (1:2) improved the gastrointestinal function in mice suffering from PT-induced gastrointestinal motility disorder. Metabolomics indicated that the PT-MO mechanism was mainly associated with the regulations of 17 and 12 metabolites and 11 and 10 pathways in urine and faeces, respectively. The common metabolic pathways were those of tyrosine, purine, tricarboxylic acid cycle, pyruvate and gluconeogenesis, which were responsible for the PT-MO intervention mechanism.

CONCLUSIONS

The PT-MO (1:2) couple mechanism mitigated the PT-induced disorders, which were related to the energy, amino acid and fatty metabolisms.

Gastrodia elata Blume (Tianma): Hope for Brain Aging and Dementia

Since aging-related diseases, including dementia, represent major public health threats to our society, physician-scientists must develop innovative, interdisciplinary strategies to open new avenues for development of alternative therapies. One such novel approach may lie in traditional Chinese medicine (TCM). Gastrodia elata Blume (G. elata, tianma) is a TCM frequently used for treatment of cerebrocardiovascular diseases (CCVDs). Recent studies of G. elata-based treatment modalities, which have investigated its pharmacologically relevant activity, potential efficacy, and safety, have employed G. elata in well-characterized, aging-related disease models, with a focus on models of aging-related dementia, such as Alzheimer's disease (AD). Here, I examine results from previous studies of G. elata, as well as related herbal preparations and pure natural products, as prophylaxis and remedies for aging-related CCVDs and dementia. Concluding, data suggest that tianma treatment may be used as a promising complementary therapy for AD.