Neuroprotective effects of the aerial parts of Polygala tenuifolia Willd extract on scopolamine-induced learning and memory impairments in mice

Long-term exposure to ionic liquid [C8mim]Br induces the potential risk of anxiety and memory deterioration through disturbing neurotransmitter systems

1-octyl-3-methylimidazolium bromide ([C8mim]Br), one of the ionic liquids (ILs), has been used in various fields as an alternative green solvent of conventional organic solvents. Increased application and stabilization of imidazole ring structure lead to its release into the aquatic environment and long-term retention. Structure-activity relationship consideration suggested that ILs may be acetylcholinesterase inhibitors; however, neurotoxicity in vivo, especially the underlying mechanisms is rarely studied. In this study, the zebrafish were exposed to 2.5-10 mg/L [C8mim]Br for 28 days to comprehensively evaluate the neurotoxicity of ILs on adult zebrafish from the behavioral profiles and neurotransmitter systems for the first time. The results indicate that zebrafish exhibit suppressed spatial working memory and anxious behaviors. To assess the potential neurotoxic mechanisms underlying the behavioral responses of zebrafish, we measured the levels of neurotransmitters and precursors, key enzyme activities, and expression levels of relevant genes. Nissl staining showed significant neural cell death in zebrafish after 28-day [C8mim]Br exposure, with corresponding decreases in the levels of neurotransmitters (acetylcholine, glutamate, 5-hydroxytryptophan, gamma-aminobutyric acid, dopamine, and norepinephrine). Furthermore, these results were associated with mRNA expression levels of the disrupted neurotransmitter key genes (th, tph2, mao, slc6a3, ache, gad67). Overall, our study determined that [C8mim]Br caused potential mental disorders like anxiety and memory deterioration in zebrafish by impairing neurotransmitter systems, providing recommendations for the industrial production and application of [C8mim]Br.

Digestive and Absorptive Properties of the Antarctic Krill Tripeptide Phe-Pro-Phe (FPF) and Its Auxiliary Memory-Enhancing Effect

Aging and stress have contributed to the development of memory disorders. Phe-Pro-Phe (FPF) was identified with high stability by mass spectrometry from simulated gastrointestinal digestion and everted gut sac products of the Antarctic krill peptide Ser-Ser-Asp-Ala-Phe-Phe-Pro-Phe-Arg (SSDAFFPFR) which was found to have a positive impact on memory enhancement. This study investigated the digestive stability, absorption, and memory-enhancing effects of FPF using nuclear magnetic resonance spectroscopy, simulated gastrointestinal digestion, in vivo fluorescence distribution analysis, mouse behavioral experiments, acetylcholine function, Nissl staining, immunofluorescence, and immunohistochemistry. FPF crossed the blood-brain barrier into the brain after digestion, significantly reduced shock time, working memory errors, and reference memory errors, and increased the recognition index. Additionally, FPF elevated ACh content; Nissl body counts; and CREB, SYN, and PSD-95 expression levels, while reducing AChE activity (P < 0.05). This implies that FPF prevents scopolamine-induced memory impairment and provides a basis for future research on memory disorders.

Quercetin-loaded nanoemulsions prevent Scopolamine-induced neurotoxicity in male rats

Quercetin (QCT) is well-known as a neuroprotective agent due to its antioxidant capacities and reinstating mitochondrial functions. Scopolamine is commonly used as a model to induce Alzheimer's disease (AD-like) symptoms. The current study develops QCT-loaded nanoemulsion (QCT-NE) accompanied by evaluating its neuro-therapeutic effectiveness against SCO-induced neurotoxicity in male rats. The QCT-NE was prepared by the spontaneous emulsification technique and characterized by using particle size, zeta potential, drug loading, in vitro drug release behavior, and stability studies. In vivo studies were done on adult Wistar rats by applying the Morris water maze (MWM) test to study spatial memory and learning. The levels of lipid peroxidation and reduced glutathione were quantitatively determined to reveal the potential mechanism of SCO-induced oxidative stress. Finally, histological studies were performed using staining techniques. The QCT-NE particle size, zeta potential, polydispersity index (PDI), and DL were obtained at 172.4 ± 16.8 nm, -29 ± 0.26 mV, 0.3 ± 0.07, and 81.42 ± 9.14 %, respectively. The QCT and more effectively QCT-NE reduced the elevation of neurobehavioral abnormalities in the MWM test in SCO-exposed rats. The results of oxidative status showed that SCO significantly could increase the LPO and decrease the GSH levels in the rat's brain. However, QCT-NE treatment was more effective than free QCT to inhibit oxidative damage and was well correlated with histopathological findings. Taken together, QCT-NE, compared to QCT, was superior in ameliorating SCO-induced AD-like symptoms due to its better neuroprotective activity and can be considered a novel supplementary therapeutic agent in AD management.

New Tiaoxin Recipe Alleviates Energy Metabolism Disorders in an APPswe/PS1DE9 Mouse Model of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a typical neurodegenerative disease with a complex etiology. Until now, there has been no effective treatment available for AD; however, improving energy dysmetabolism, the key pathological event in the early stage of AD, can effectively delay the progression of AD.

OBJECTIVE

This paper aims to investigate the therapeutic effect and potential mechanism of the new Tiaoxin recipe on early AD.

METHODS

APP/PS1 mice were divided into a model group, a new Tiaoxin recipe group, and a donepezil group, and C57/BL mice were used for the control group. Mouse cognitive and learning abilities were tested using the Morris water maze test and a new object-recognition experiment. The 42 amino acid form of amyloid β peptide (Aβ1-42) content was detected by enzyme-linked immunosorbent assay, the senile plaque area was detected by thioflavin S staining, and the senescence- associated β-galactosidase (SA-β-gal)-positive area was detected by chemical staining. Also, the adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NAD+), and nicotinamide adenine dinucleotide hydride (NADH) contents were detected using a biochemical method, and the cluster of differentiation 38 (CD38) and silent mating-type information regulation 2 homolog 3 (SIRT3) protein expression levels were detected by immunofluorescence and Western blot analysis.

RESULTS

Compared with those of the control group, the learning and memory abilities of the model group were impaired; the senile plaque deposition, Aβ1-42 content, and SA-βgal-positive staining area were increased; the ATP concentration, NAD+ concentration, and NAD+/NADH ratio were decreased; the CD38 protein expression level was increased; and the SIRT3 protein expression level was decreased. Following intervention with the new Tiaoxin recipe, the learning and memory abilities were improved; the senile plaque deposition, Aβ1-42 content, and SA-βgal-positive area were reduced; the ATP concentration, NAD+ concentration, and NAD+/NADH ratio were increased; CD38 protein expression was decreased, and SIRT3 protein expression was increased.

CONCLUSION

This study shows that the new Tiaoxin Recipe can improve cognitive ability and reduce the Aβ1-42 content and senile plaque deposition in APP/PS1 mice, which may occur through the downregulation of CD38 protein expression, upregulation of SIRT3 protein expression, restoration of the NAD+ level, promotion of ATP synthesis, mitigation of energy metabolism disorders.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Perfluorononanoic Acid Induces Neurotoxicity via Synaptogenesis Signaling in Zebrafish

Perfluorononanoic acid (PFNA), commonly used as an alternative polyfluorinated compound (PFC) of perfluorooctanoic acid (PFOA), has been widely detected in the aquatic environment. Previous ecotoxicological and epidemiological results suggested that some neurobehavioral effects were associated with PFC exposure; however, the ecological impacts and underlying neurotoxicity mechanisms remain unclear, particularly in aquatic organisms during sensitive, early developmental stages. In this study, zebrafish embryos were exposed to environmentally relevant concentrations of PFNA for 120 h, and the neurological effects of PFNA were comprehensively assessed using transcriptional, biochemical, morphological, and behavioral assays. RNA sequencing and advanced bioinformatics analyses predicted and characterized the key biological processes and pathways affected by PFNA exposure, which included the synaptogenesis signaling pathway, neurotransmitter synapse, and CREB signaling in neurons. Neurotransmitter levels (acetylcholine, glutamate, 5-hydroxytryptamine, γ-aminobutyric acid, dopamine, and noradrenaline) were significantly decreased in zebrafish larvae, and the Tg(gad67:GFP) transgenic line revealed a decreased number of GABAergic neurons in PFNA-treated larvae. Moreover, the swimming distance, rotation frequency, and activity degree were also significantly affected by PFNA, linking molecular-level changes to behavioral consequences.

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.

Anoectochilus roxburghii flavonoids extract ameliorated the memory decline and reduced neuron apoptosis via modulating SIRT1 signaling pathway in senescent mice

ETHNOPHARMACOLOGICAL RELEVANCE

Anoectochilus roxburghii (A. roxburghii) is a precious herb and folk medicine in many Asian countries. It has been used traditionally to treat diabetes, etc., and also used as a dietary therapy to delay senescence.

AIM OF THE STUDY

This study was to evaluate the neuroprotective effects of A. roxburghii flavonoids extract (ARF) and whether its effects were due to the regulation of SIRT1 signaling pathway in senescent mice and in D-galactose (D-gal) induced aging in SH-SY5Y cells.

MATERIALS AND METHODS

18-month-old mice were randomly divided into senescent model, low-dose ARF, high-dose ARF and vitamin E group. 2-Month-old mice were as a control group. After 8 weeks treatment, Morris water maze (MWM) was performed. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), monoamine oxidase (MAO) and acetylcholinesterase (ACh-E) in the cortex were determined. Hippocampus morphologic changes were observed with haematoxylin and eosin (H&E), Nissl, senescence-associated-galactosidase (SA-β-gal) and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining. Apoptosis-related molecular expressions in the hippocampus were performed by western blotting. Furthermore, after stimulated by EX527 (a SIRT1 inhibitor), the SIRT1-dependent neuroprotective effects of ARF were determined by measuring SRIT1 and p53 expression in SH-SY5Y aging cells induced by D-gal.

RESULTS

ARF could significantly ameliorate memory decline in senescent mice and reduce the generations of ROS, MDA and the activities of MAO and ACh-E, while increasing SOD activities in the cortex of aging mice. ARF obviously improved hippocampus pathological alterations, increased the number of Nissl bodies, while reducing senescent and apoptotic cells in senescent mice hippocampus. Further, ARF positively regulated SIRT1 expression, and reduced apoptosis-related molecules p53, p21 and Caspase-3 expression, while increasing the ratio of Bcl-2/Bax. In D-gal-induced SH-SY5Y cells, the effects of ARF on SIRT1 and p53, and the ability of scavenging ROS were mostly abolished after incubation with the EX527.

CONCLUSIONS

ARF, in a SIRT1-dependent manner, exerted neuroprotection via modulating SIRT1/p53 signaling pathway against memory decline and apoptosis due to age-induced oxidative stress damage in senescent mice.

Minocycline attenuates cholinergic dysfunction and neuro-inflammation-mediated cognitive impairment in scopolamine-induced Alzheimer's rat model

OBJECTIVE

Minocycline, a semisynthetic tetracycline-derived antibiotic, has various pharmacological effect such as anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects. The current study investigated the involvement of neuro-inflammatory, oxidative stress, and cholinergic markers in neuroprotection by minocycline against scopolamine-induced brain damage.

METHODS

Minocycline was administered (oral, 10, 15, and 30 mg/kg, daily) to groups of amnesic rats for 21 days. Passive avoidance memory and spatial learning and memory were assessed. Following that, oxidative stress, cholinergic function, and neuro-inflammation markers were evaluated in the brain tissue.

RESULTS

According to our biochemical data, treatment of the scopolamine-injured rats with minocycline decreased the levels of malondialdehyde and acetylcholinesterase (AChE) as well as mRNA expression of AChE and neuro-inflammation markers (tumor necrosis factor-α, interleukin (IL)-1β, IL-6). It also increased the total thiol levels and superoxide dismutase activity as well as mRNA expression of cholinergic receptor M1 (ChRM1). Moreover, minocycline modified distance and latencies in Morris water maze, prolonged latency to enter the black zone and light time while decreasing time spent and frequency of entries to darkness.

CONCLUSION

Taken together, the data indicate that treatment with minocycline improved memory dysfunction mediated possibly through restoring AChE and ChRM1 levels, oxidant/antioxidant balance, as well as inhibiting inflammatory responses.

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.

Aconiti lateralis Radix Praeparata inhibits Alzheimer's disease by regulating the complex regulation network with the core of GRIN1 and MAPK1

CONTEXT

Current medicine for Alzheimer's disease (AD) cannot effectively reverse or block nerve injury. Traditional Chinese Medicine practice and research imply Aconiti lateralis Radix Praeparata (Fuzi) may meet this goal.

OBJECTIVE

Analysing the anti-AD effect of Fuzi and its potential molecular mechanism.

MATERIALS AND METHODS

AD model cells were treated with Fuzi in 0-300 mg/mL for 24 h in 37 °C. The cell viability (CV) and length of cell projections (LCP) for each group were observed, analysed, and standardised using control as a baseline (CV_s and LCP_s). The Fuzi and AD relevant genes were identified basing on databases, and the molecular mechanism of Fuzi anti-AD was predicted by network analysis.

RESULTS

Experiment results showed that Fuzi in 0.4 mg/mL boosted LCP (LCP_s = 1.2533, p ≤ 0.05), and in 1.6-100 mg/mL increased CV (CV_s from 1.1673 to 1.3321, p ≤ 0.05). Bioinformatics analysis found 17 Fuzi target genes (relevant scores ≥ 20), showing strong AD relevant signals (RMS_p ≤ 0.05, related scores ≥ 5), enriched in the pathways regulating axon growth, synaptic plasticity, cell survival, proliferation, apoptosis, and death (p ≤ 0.05). Especially, GRIN1 and MAPK1 interacted with APP protein and located in the key point of the "Alzheimer's disease" pathway.

DISCUSSION AND CONCLUSIONS

These results suggest that Fuzi may have therapeutic and prevention potential in AD, and GRIN1 and MAPK1 may be the core of the pathways of the Fuzi anti-AD process. Fuzi should be studied more extensively, especially for the prevention of AD.

Chinese herbal medicine for mild cognitive impairment using mini-mental state examination: A systematic review and meta-analysis

INTRODUCTION

The prevalence of mild cognitive impairment (MCI) in the elderly population aged 60 to 84 years ranges from 6.7% to 25.2%, and the effective prevention and reversal of MCI progression to Alzheimer disease (AD) is crucial. The mini mental state examination (MMSE) is the most commonly used screening tool in Chinese outpatient clinics, with sufficient sensitivity and specificity to allow useful stratification from average to abnormal with adequate consideration of age and education.

OBJECTIVE

To investigate the clinical significance of Chinese herbs on MMSE scores in MCI patients and discuss the effectiveness of Chinese herbs through pharmacology.

METHODS

Three English databases and 4 Chinese databases we have searched, and the risk of bias was assessed according to the Cochrane tool. Statistics will be used for heterogeneity assessment, sensitivity analysis, data synthesis, funnel plot generation and subgroup analysis. If sufficiently homogeneous studies are found, a Meta-analysis will be performed, with subgroups describing any differences.

RESULTS

A total of 21 studies were included, 4 studies were placebo-controlled, 14 Chinese Herbal Medicines (CHMs) were compared with other cognitive improvements, 3 CHMs were combined with other medications, and the results of 17 studies favored the herbal group.

CONCLUSION

The results indicate that herbal medicine can improve MMSE scores, and herbal medicine combined with other drugs that can improve cognition can significantly improve MMSE scores, but there are methodological flaws in the study. Experimental studies have found a basis for the ability of herbs to improve cognition and memory impairment, and herbal medicine has great potential to improve MCI cognition. Keywords mild cognitive impairment, herbal medicine, MMSE, systematic evaluation, meta-analysis. PROSPERO international prospective register of systematic reviews protocol registration number: CRD42020202368.

Traditional Chinese Medicine Intervenes in Vascular Dementia: Traditional Medicine Brings New Expectations

Vascular dementia (VD) is one of the most common forms of dementia, referring to a group of symptoms that mainly manifest as advanced neurocognitive dysfunction induced by cerebrovascular disease (CVD). A significant number of studies have shown that traditional Chinese medicine (TCM) has a clinical impact on VD and thus has promising prospects. There have been many discussions regarding the pharmacological mechanisms involved in treatment of the kidney, elimination of turbidity, and promotion of blood circulation. TCM has a prominent effect on improving patients' cognitive function and quality of life. In this review, we summarize the pathogenesis of VD in modern medicine and TCM, traditional prescriptions, single-agent effective ingredients and their pharmacological mechanisms for treating VD, highlight TCM's characteristics, and discuss TCM's multi-targeted mechanism for the treatment of VD.

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.

Phytochemical Analysis, In Vitro Anticholinesterase, Antioxidant Activity and In Vivo Nootropic Effect of Ferula ammoniacum (Dorema ammoniacum) D. Don. in Scopolamine-Induced Memory Impairment in Mice

Background: Ferula ammoniacum (D. Don) is one of the endemic medicinal plants that is traditionally used to treat a number of diseases. Although the plant has been used to enhance memory, the investigational evidence supporting the nootropic effect was unsubstantial. Hence, the rationale for this study was to assess the potential beneficial effect of F. ammoniacum seed extracts on learning and memory in mice. Methods: The powdered plant samples (aerial parts) were subjected to extraction ad fractionation. Among the extracts, crude and ethyl acetate extracts were screened for major phytochemicals through HPLC analysis. All the extracts were evaluated for the in vitro anticholinesterase (AChE and BChE) and antioxidant potentials. Among the extracts the active fraction was further assessed for improving learning and memory in mice using behavioural tests like Y-maze and novel object recognition test (NORT) using standard protocols. After behavioural tests, all the animals were sacrificed and brains tissues were assessed for the ex vivo anticholinesterase and antioxidant potentials. Results: Phytochemicals like chlorogenic acid, quercetin, mandelic acid, phloroglucinol, hydroxy benzoic acid, malic acid, epigallocatechin gallate, ellagic acid, rutin, and pyrogallol were identified in crude methanolic extract (Fa.Met) and ethyl acetate fraction (Fa.EtAc) through HPLC. Fa.EtAc and Fa.Chf extracts more potently inhibited AChE and BChE with IC50 values of 40 and 43 µg/mL, and 41 and 42 µg/mL, respectively. Similarly highest free radical scavenging potential was exhibited by Fa.EtAc fraction against DPPH (IC50 = 100 µg/mL) and ABTS (IC50 = 120 µg/mL). The extract doses, 100 and 200 mg/kg body weight significantly (p < 0.01) improved the short-term memory by increasing the percent spontaneous alternation in the Y-maze test along with increasing discrimination index in the NORT that clearly indicated the enhancement in the recognition memory of mice. Conclusion: The extracts more potently scavenged the tested free radicals, exhibited anticholinesterase activities, improved the learning abilities and reduced the memory impairment induced by scopolamine in mice model thus suggesting that these extracts could be effectively used for the management of oxidative stress, neurodegenerative diseases and memory loss.