Isorhynchophylline ameliorates cognitive impairment via modulating amyloid pathology, tau hyperphosphorylation and neuroinflammation: Studies in a transgenic mouse model of Alzheimer's disease

Alkaloids in Uncaria rhynchophylla improves AD pathology by restraining CD4+ T cell-mediated neuroinflammation via inhibition of glycolysis in APP/PS1 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria rhynchophylla (Miq.) Miq.ex Havil. was a classical medicinal plant exhibiting the properties of extinguishing wind, arresting convulsions, clearing heat and pacifying the liver. Clinically, it could be utilized for the treatment of central nervous system-related diseases, such as Alzheimer's disease. U. rhynchophylla (UR) and its major ingredient alkaloid compounds (URA) have been proved to exert significant neuroprotective effects. However, the potential mechanism aren't fully understood.

AIM OF THE STUDY

This study systematically examined the therapeutic effects of URA on AD pathology in APP-PS1 mice, and revealed the potential mechanism of action.

MATERIALS AND METHODS

The cognitive ability was evaluated by morris water maze test in APP-PS1 mice. The H&E staining was used to observe the tissue pathological changes. The ELISA kits were used to detect the level of inflammatory factors. The flow cytometry was used to analyze the percentage of CD4+ effector T cells (Teffs) in spleen. The immunofluorescent staining was performed to count the Teffs and microglia in brain. The protein expression was analyzed by western blot. In vitro, the lymphocyte proliferation induced by ConA was performed by CCK-8 kits. The IFN-γ, IL-17, and TNF-α production were detected by ELISA kits. The effects of URA on glycolysis and the involvement of PI3K/Akt/mTOR signaling pathway was analyzed by Lactic Acid assay kit and western blot in ConA-induced naive T cell.

RESULTS

URA treatment improved AD pathology effectively as demonstrated by enhanced cognitive ability, decreased Aβ deposit and Tau phosphorylation, as well as reduced neuron apoptosis. Also, the neuroinflammation was significantly alleviated as evidenced by decreased IFN-γ, IL-17 and increased IL-10, TGF-β. Notably, URA treatment down-regulated the percentage of Teffs (Th1 and Th17) in spleen, and reduced the infiltration of Teffs and microglia in brain. Meanwhile, the Treg cell was up-regulated both in spleen and brain. In vitro, URA was capable of attenuating the spleen lymphocyte proliferation and release of inflammatory factors provoked by ConA. Interestingly, glycolysis was inhibited by URA treatment as evidenced by the decrease in Lactic Acid production and expression of HK2 and GLUT1 via regulating PI3K/Akt/mTOR signaling pathway in ConA-induced naive T cell.

CONCLUSION

This study proved that URA could improve AD pathology which was possibly attributable to the restraints of CD4+ T cell mediated neuroinflammation via inhibiting glycolysis.

Revolutionizing Neurotherapeutics: Nanocarriers Unveiling the Potential of Phytochemicals in Alzheimer's Disease

Neurological disorders pose a huge worldwide challenge to the healthcare system, necessitating innovative strategies for targeted drug delivery to the central nervous system. Alzheimer's disease (AD) is an untreatable neurodegenerative condition characterized by dementia and alterations in a patient's physiological and mental states. Since ancient times, medicinal plants have been an important source of bioactive phytochemicals with immense therapeutic potential. This review investigates new and safer alternatives for prevention and treatment of disease related to inevitable side effects associated with synthetic compounds. This review examines how nanotechnology can help in enhancing the delivery of neuroprotective phytochemicals in AD. Nevertheless, despite their remarkable neuroprotective properties, these natural products often have poor therapeutic efficacy due to low bioavailability, limited solubility and imperfect blood brain barrier (BBB) penetration. Nanotechnology produces personalized drug delivery systems which are necessary for solving such problems. In overcoming these challenges, nanotechnology might be employed as a way forward whereby customized medication delivery systems would be established as a result. The use of nanocarriers in the design and application of important phytochemicals is highlighted by this review, which indicate potential for revolutionizing neuroprotective drug delivery. We also explore the complications and possibilities of using nanocarriers to supply nutraceuticals and improve patients' standard of living, and preclinical as well as clinical investigations displaying that these techniques are effective in mitigating neurodegenerative diseases. In order to fight brain diseases and improve patient's health, scientists and doctors can employ nanotechnology with its possible therapeutic interventions.

Systems genetics identifies methionine as a high risk factor for Alzheimer's disease

As a dietary strategy, methionine restriction has been reported to promote longevity and regulate metabolic disorders. However, the role and possible regulatory mechanisms underlying methionine in neurodegenerative diseases such as Alzheimer's disease (AD), remain unexplored. This study utilized the data from BXD recombinant inbred (RI) mice to establish a correlation between the AD phenotype in mice and methionine level. Gene enrichment analysis indicated that the genes associated with the concentration of methionine in the midbrain are involved in the dopaminergic synaptic signaling pathway. Protein interaction network analysis revealed that glycogen synthase kinase 3 beta (GSK-3β) was a key regulator of the dopaminergic synaptic pathway and its expression level was significantly correlated with the AD phenotype. Finally, in vitro experiments demonstrated that methionine deprivation could reduce the expression of Aβ and phosphorylated Tau, suggesting that lowering methionine levels in humans may be a preventive or therapeutic strategy for AD. In conclusion, our findings support that methionine is a high risk factor for AD. These findings predict potential regulatory network, theoretically supporting methionine restriction to prevent AD.

Role of Tau Protein in Neurodegenerative Diseases and Development of Its Targeted Drugs: A Literature Review

Tau protein is a microtubule-associated protein that is widely distributed in the central nervous system and maintains and regulates neuronal morphology and function. Tau protein aggregates abnormally and forms neurofibrillary tangles in neurodegenerative diseases, disrupting the structure and function of neurons and leading to neuronal death, which triggers the initiation and progression of neurological disorders. The aggregation of tau protein in neurodegenerative diseases is associated with post-translational modifications, which may affect the hydrophilicity, spatial conformation, and stability of tau protein, promoting tau protein aggregation and the formation of neurofibrillary tangles. Therefore, studying the role of tau protein in neurodegenerative diseases and the mechanism of aberrant aggregation is important for understanding the mechanism of neurodegenerative diseases and finding therapeutic approaches. This review describes the possible mechanisms by which tau protein promotes neurodegenerative diseases, the post-translational modifications of tau protein and associated influencing factors, and the current status of drug discovery and development related to tau protein, which may contribute to the development of new therapeutic approaches to alleviate or treat neurodegenerative diseases.

Gut dysbiosis aggravates cognitive deficits, amyloid pathology and lipid metabolism dysregulation in a transgenic mouse model of Alzheimer's disease

Gut dysbiosis, a well-known risk factor to triggers the progression of Alzheimer's disease (AD), is strongly associated with metabolic disturbance. Trimethylamine N-oxide (TMAO), produced in the dietary choline metabolism, has been found to accelerate neurodegeneration in AD pathology. In this study, the cognitive function and gut microbiota of TgCRND8 (Tg) mice of different ages were evaluated by Morris water maze task (MWMT) and 16S rRNA sequencing, respectively. Young pseudo germ-free (PGF) Tg mice that received faecal microbiota transplants from aged Tg mice and wild-type (WT) mice were selected to determine the role of the gut microbiota in the process of neuropathology. Excessive choline treatment for Tg mice was used to investigate the role of abnormal choline metabolism on the cognitive functions. Our results showed that gut dysbiosis, neuroinflammation response, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and cyclin-dependent kinase 5 (CDK5)/transcription 3 (STAT3) activation occurred in Tg mice age-dependently. Disordered microbiota of aged Tg mice accelerated AD pathology in young Tg mice, with the activation of CDK5/STAT3 signaling in the brains. On the contrary, faecal microbiota transplantation from WT mice alleviated the cognitive deficits, attenuated neuroinflammation, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and suppressed CDK5/STAT3 pathway activation in Tg mice. Moreover, excessive choline treatment was also shown to aggravate the cognitive deficits, Aβ deposition, neuroinflammation and CDK5/STAT3 pathway activation. These findings provide a novel insight into the interaction between gut dysbiosis and AD progression, clarifying the important roles of gut microbiota-derived substances such as TMAO in AD neuropathology.

Critical thinking of Alzheimer's transgenic mouse model: current research and future perspective

Transgenic models are useful tools for studying the pathogenesis of and drug development for Alzheimer's Disease (AD). AD models are constructed usually using overexpression or knock-in of multiple pathogenic gene mutations from familial AD. Each transgenic model has its unique behavioral and pathological features. This review summarizes the research progress of transgenic mouse models, and their progress in the unique mechanism of amyloid-β oligomers, including the first transgenic mouse model built in China based on a single gene mutation (PSEN1 V97L) found in Chinese familial AD. We further summarized the preclinical findings of drugs using the models, and their future application in exploring the upstream mechanisms and multitarget drug development in AD.

The activation of spliced X-box binding protein 1 by isorhynchophylline therapy improves diabetic encephalopathy

The primary symptom of diabetic encephalopathy (DE), a kind of central diabetic neuropathy caused by diabetes mellitus (DM), is cognitive impairment. In addition, the tetracyclic oxindole alkaloid isorhynchophylline (IRN) helps lessen cognitive impairment. However, it is still unclear how IRN affects DM and DE and what mechanisms are involved. The effectiveness of IRN on brain insulin resistance was carefully examined in this work, both in vitro and in vivo. We found that IRN accelerates spliced form of X-box binding protein 1 (sXBP1) translocation into the nucleus under high glucose conditions in vitro. IRN also facilitates the nuclear association of pCREB with sXBP1 and the binding of regulatory subunits of phosphatidylinositol 3-kinase (PI3K) p85α or p85β with XBP1 to restore high glucose impairment. Also, IRN treatment improves high glucose-mediated impairment of insulin signaling, endoplasmic reticulum stress, and pyroptosis/apoptosis by depending on sXBP1 in vitro. In vivo studies suggested that IRN attenuates cognitive impairment, ameliorating peripheral insulin resistance, activating insulin signaling, inactivating activating transcription factor 6 (ATF6) and C/EBP homology protein (CHOP), and mitigating pyroptosis/apoptosis by stimulation of sXBP1 nuclear translocation in the brain. In summary, these data indicate that IRN contributes to maintaining insulin homeostasis by activating sXBP1 in the brain. Thus, IRN is a potent antidiabetic agent as well as an sXBP1 activator that has promising potential for the prevention or treatment of DE.

Research progress of plant-derived natural alkaloids in central nervous system diseases

Central nervous system (CNS) disease is one of the most important causes of human death. Because of their complex pathogenesis, more and more attention has been paid to them. At present, drug treatment of the CNS is the main means; however, most drugs only relieve symptoms, and some have certain toxicity and side effects. Natural compounds derived from plants can provide safer and more effective alternatives. Alkaloids are common nitrogenous basic organic compounds found in nature, which exist widely in many kinds of plants and have unique application value in modern medicine. For example, Galantamine and Huperzine A from medicinal plants are widely used drugs on the market to treat Alzheimer's disease. Therefore, the main purpose of this review is to provide the available information on natural alkaloids with the activity of treating central nervous system diseases in order to explore the trends and perspectives for the further study of central nervous system drugs. In this paper, 120 alkaloids with the potential effect of treating central nervous system diseases are summarized from the aspects of sources, structure types, mechanism of action and structure-activity relationship.

Neurovascular glial unit: A target of phytotherapy for cognitive impairments

BACKGROUND

Neurovascular glial unit (NVGU) dysfunction has been reported to be an early and critical event in the pathophysiology of Alzheimer's disease (AD) and vascular dementia (VD). Although herbal medicines, with their favorable safety profiles and low adverse effects, have been suggested to be useful for the treatment of cognitive impairment, the potential role of the NVGU as the target of the effects of herbal medicines is still unclear.

PURPOSE

This review aimed to retrieve evidence from experimental studies of phytopharmaceuticals targeting the NVGU for the treatment of cognitive impairment in AD and VD, and discussed the potential of phytopharmaceuticals to improve cognitive impairment from the perspective of the NVGU.

STUDY DESIGN AND METHODS

We systematically searched PubMed, Google Scholar, Web of Science, and CNKI. The keywords used for searching information on the NVGU in the treatment of cognitive impairments included "Alzheimer's disease," "Vascular dementia," "Herbal medicines," "Natural products," "Neurovascular," "Adverse reaction," and "Toxicity, etc." We selected studies on the basis of predefined eligibility criteria.

RESULTS

NVGU mainly consists of endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes, and neurons, and damage to these cells can induce cognitive impairment by impairing the blood-brain barrier (BBB) and cerebral blood flow (CBF) as well as neuronal function. The active components of herbal medicines, including Ginkgo biloba L., Ginseng Radix et Rhizoma, Epimedium Folium, Chuanxiong Rhizoma, Carthami flos, and Acorus tatarinowii Schott, as well as traditional Chinese medicine prescriptions have shown the potential to improve BBB function and increase CBF to prevent cognitive impairment by inhibiting astrocyte and microglia activation, protecting oligodendrocyte myelin function, reducing neuronal apoptosis, and promoting angiogenesis.

CONCLUSIONS

Herbal medicines demonstrate great potential to prevent cognitive impairment. Multiple components from herbal medicines may function through different signaling pathways to target the NVGU. Future studies using novel drug-carrier or delivery systems targeting the NVGU will certainly facilitate the development of phytopharmaceuticals for AD and VD.

Side effects based network construction and drug repositioning of ropinirole as a potential molecule for Alzheimer's disease: an in-silico, in-vitro, and in-vivo study

Alzheimer's disease (AD) is the leading cause of dementia in older adults. Drug repositioning is a process of finding new therapeutic applications for existing drugs. One of the methods in drug repositioning is to use the side-effect profile of a drug to identify a new therapeutic indication. The drugs with similar side-effects may act on similar biological targets and could affect the same biochemical process. In this study, we explored the Food and Drug Administration-approved drugs using PROMISCUOUS database to find those that have adverse effects profile comparable with the ligands being studied or used to treat AD. Here, we found that the ropinirole, a dopamine receptor agonist, shared a maximum number of side-effects with the drugs proven beneficial for treating AD. Furthermore, molecular modelling demonstrated that ropinirole exhibited strong binding affinity (-9.313 kcal/mol) and best ligand efficiency (0.49) with sigma-1 receptor. Here, we observed that the quaternary amino group of ropinirole is essential for binding with sigma-1 receptor. Molecular dynamic simulation indicated that the movement of the carboxy-terminal helices (α4/α5) could play a major role in the receptor's physiological functions. The neurotoxicity induced by Aβ25-35 in SH-SY5Y cells was reduced by ropinirole at concentrations 10, 30, and 50 µM. The effect on spatial learning and memory was examined in mice with Aβ25-35 induced memory deficit using the radial arm maze. Ropinirole (10 and 20 mg/kg) significantly improved the short and long-term memories in the radial arm maze test. Our results suggest that ropinirole has the potential to be repositioned for AD treatment.Communicated by Ramaswamy H. Sarma.

Insulin-degrading enzyme: Roles and pathways in ameliorating cognitive impairment associated with Alzheimer's disease and diabetes

Accumulation of amyloid-β in the central nervous system is a common feature of Alzheimer's disease (AD) and diabetes-related cognitive impairment. Since the insulin-degrading enzyme (IDE) can break down amyloid-β plaques, there is considerable interest in using this enzyme to treat both neurological disorders. In this review, we have summarized the pre-clinical and clinical research on the potential application of IDE for the improvement of cognitive impairment. Furthermore, we have presented an overview of the main pathways that can be targeted to mitigate the progression of AD and the cognitive impairment caused by diabetes.

Pharmacological mechanism of natural drugs and their active ingredients in the treatment of arrhythmia via calcium channel regulation

Arrhythmia is characterized by abnormal heartbeat rhythms and frequencies caused by heart pacing and conduction dysfunction. Arrhythmia is the leading cause of death in patients with cardiovascular disease, with high morbidity and mortality rates, posing a serious risk to human health. Natural drugs and their active ingredients, such as matrine(MAT), tetrandrine(TET), dehydroevodiamine, tanshinone IIA, and ginsenosides, have been widely used for the treatment of atrial fibrillation, ventricular ectopic beats, sick sinus syndrome, and other arrhythmia-like diseases owing to their unique advantages. This review summarizes the mechanism of action of natural drugs and their active ingredients in the treatment of arrhythmia via the regulation of Ca²⁺, such as alkaloids, quinones, saponins, terpenoids, flavonoids, polyphenols, and lignan compounds, to provide ideas for the innovative development of natural drugs with potential antiarrhythmic efficacy.

Isorhynchophylline alleviates cartilage degeneration in osteoarthritis by activating autophagy of chondrocytes

CONTEXT

Osteoarthritis is a common degenerative disease, the cause of it is still unknown, and the treatment mainly focuses on improving symptoms. Studies have found that Isorhynchophylline (Isorhy) has antioxidant, anti-inflammatory, antiproliferative and neuroprotective effects.

OBJECTIVE

This study investigates the role and mechanism of Isorhy in OA.

METHODS

The destabilized medial meniscus model was used to mimic OA. Fifteen male Sprague Dawley rats were partitioned into three portions: Normal group, OA group (surgery; normal saline treatment) and OA + Isorhy group (surgery; 50 μM Isorhy treatment) were performed on the first day of every week from the 5th to the 8th week after surgery. After 4 weeks of drug treatment, the rats have been processed without debridement of the knee specimens and fixed using 4% paraformaldehyde for two days. The morphological analysis was performed by H&E, Safranin O-Fast green staining and micro-CT analysis. The specimens were researched employing Micro-CT. In the part of the aggregate methods that were evaluated by qRT-PCR and western blot of the following proteins LC3II/LC3I, Beclin-1, ATG5, ATG7, MMP3 andMMP13. Akt/PI3K signaling related proteins (p-AKT, AKT, p-PI3K, PI3K, p-mTOR, mTOR) were detected by Western blot. BECLIN1 and MMP3 were detected by Immunofluorescence assay.

RESULTS

In this present research, it was proved that autophagy-related and cartilage matrix-related proteins in osteoarthritis could be regulated by Isorhynchophylline treatment. The transcriptome sequencing results suggested the regulation was closely associated with PI3K/AKT/mTOR pathway, thereby alleviating osteoarticular inflammation. In-depth study showed that Isorhy could also affect OA in rat OA models, that was indicated by H&E, Safranin O-Fast green staining, and also micro-CT analysis.

CONCLUSION

Our findings indicated that Isorhy could be regarded as a prospective candidate for OA treatment.

Patchouli alcohol attenuates the cognitive deficits in a transgenic mouse model of Alzheimer's disease via modulating neuropathology and gut microbiota through suppressing C/EBPβ/AEP pathway

BACKGROUND

Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by progressive cognitive dysfunctions and behavioral impairments. Patchouli alcohol (PA), isolated from Pogostemonis Herba, exhibits multiple pharmacological properties, including neuroprotective effects. This study aimed to investigate the therapeutic effects of PA against AD using the TgCRND8 transgenic AD mouse model, and to explore the underlying mechanisms targeting CCAAT/enhancer-binding protein β/asparagine endopeptidase (C/EBPβ/AEP) signaling pathway.

METHODS

After genotyping to confirm the transgenicity, drug treatments were administered intragastrically once daily to 3-month-old TgCRND8 mice for 4 consecutive months. Several behavioral tests were applied to assess different aspects of neurological functions. Then the brain and colon tissues were harvested for in-depth mechanistic studies. To further verify whether PA exerts anti-AD effects via modulating C/EBPβ/AEP signaling pathway in TgCRND8 mice, adeno-associated virus (AAV) vectors encoding CEBP/β were bilaterally injected into the hippocampal CA1 region in TgCRND8 mice to overexpress C/EBPβ. Additionally, the fecal microbiota transplantation (FMT) experiment was performed to verify the potential role of gut microbiota on the anti-AD effects of PA.

RESULTS

Our results showed that PA treatment significantly improved activities of daily living (ADL), ameliorated the anxiety-related behavioral deficits and cognitive impairments in TgCRND8 mice. PA modulated the amyloid precursor protein (APP) processing. PA also markedly reduced the levels of beta-amyloid (Aβ) ₄₀ and Aβ₄₂, suppressed Aβ plaque burdens, inhibited tau protein hyperphosphorylation at several sites and relieved neuroinflammation in the brains of TgCRND8 mice. Moreover, PA restored gut dysbiosis and inhibited the activation of the C/EBPβ/AEP signaling pathway in the brain and colon tissues of TgCRND8 mice. Interestingly, PA strikingly alleviated the AD-like pathologies induced by the overexpression of C/EBPβ in TgCRND8 mice. Additionally, the FMT of fecal microbiota from the PA-treated TgCRND8 mice significantly alleviated the cognitive impairments and AD-like pathologies in the germ-free TgCRND8 mice.

CONCLUSION

All these findings amply demonstrated that PA could ameliorate the cognitive deficits in TgCRND8 mice via suppressing Aβ plaques deposition, hyperphosphorylation of tau protein, neuroinflammation and gut dysbiosis through inhibiting the activation of C/EBPβ/AEP pathway, suggesting that PA is a promising naturally occurring chemical worthy of further development into the pharmaceutical treatment of AD.

Medicinal Herbs and Their Derived Ingredients Protect against Cognitive Decline in In Vivo Models of Alzheimer’s Disease

Alzheimer’s disease (AD) has pathological hallmarks including amyloid beta (Aβ) plaque formation. Currently approved single-target drugs cannot effectively ameliorate AD. Medicinal herbs and their derived ingredients (MHDIs) have multitarget and multichannel properties, engendering exceptional AD treatment outcomes. This review delineates how in in vivo models MHDIs suppress Aβ deposition by downregulating β- and γ-secretase activities; inhibit oxidative stress by enhancing the antioxidant activities and reducing lipid peroxidation; prevent tau hyperphosphorylation by upregulating protein phosphatase 2A expression and downregulating glycogen synthase kinase-3β expression; reduce inflammatory mediators partly by upregulating brain-derived neurotrophic factor/extracellular signal-regulated protein kinase 1/2-mediated signaling and downregulating p38 mitogen-activated protein kinase (p38 MAPK)/c-Jun N-terminal kinase (JNK)-mediated signaling; attenuate synaptic dysfunction by increasing presynaptic protein, postsynaptic protein, and acetylcholine levels and preventing acetylcholinesterase activity; and protect against neuronal apoptosis mainly by upregulating Akt/cyclic AMP response element-binding protein/B-cell lymphoma 2 (Bcl-2)-mediated anti-apoptotic signaling and downregulating p38 MAPK/JNK/Bcl-2-associated x protein (Bax)/caspase-3-, Bax/apoptosis-inducing factor-, C/EBP homologous protein/glucose-regulated protein 78-, and autophagy-mediated apoptotic signaling. Therefore, MHDIs listed in this review protect against Aβ-induced cognitive decline by inhibiting Aβ accumulation, oxidative stress, tau hyperphosphorylation, inflammation, synaptic damage, and neuronal apoptosis in the cortex and hippocampus during the early and late AD phases.

Synergistic effect of mild traumatic brain injury and alcohol aggravates neuroinflammation, amyloidogenesis, tau pathology, neurodegeneration, and blood-brain barrier alterations: Impact on psychological stress

After a mild traumatic brain injury (mTBI), victims often experience emotional/psychological stress such as heightened irritability, anxiety, apathy, and depression. Severe mental health complications are common in military populations following a combat-acquired TBI and intensified unhealthy alcohol use. The high prevalence of alcohol abuse among TBI victims underscores how alcohol abuse exacerbates emotional/psychological symptoms such as depression and anxiety. The experimental mTBI was induced in vivo by fluid percussion injury (15 psi) in mice and ethanol diet feeding continued for 28 days. We analyzed different biomarkers of the biochemical mechanisms and pathophysiology of neurological damage, and functional outcome of psychological stress by sucrose preference, and light-dark tests. We demonstrated that the synergistic effect of TBI and alcohol leads to psychological stress such as depression and anxiety. The studies showed that oxidative stress, amyloidogenesis, tau pathology, neuroinflammation, and neurodegeneration markers were elevated, and glial activation and blood-brain barrier (BBB) damage were exacerbated during the synergistic effect of TBI and alcohol. Further, we studied the biochemical mechanisms of psychological stress that showed the significant reduction of 5-HT1AR, neuropeptide-Y, and norepinephrine, and an increase in monoamine oxidase-a in the combined effect of TBI and alcohol. This work suggested that the combined TBI and alcohol-induced effect leads to depression and anxiety, via sequential biochemical changes that cause neuroinflammation, amyloidogenesis, tau pathology, neurodegeneration, and BBB alterations. This clinically relevant study will contribute to developing a comprehensive therapeutic approach for patients suffering from TBI and alcohol-mediated neurological damage and psychological stress.

Quantitative imaging of natural products in fine brain regions using desorption electrospray ionization mass spectrometry imaging (DESI-MSI): Uncaria alkaloids as a case study

Uncaria species (Rubiaceae) are used as traditional Chinese medicines (TCMs) to treat central nervous system (CNS) diseases, and monoterpene indole alkaloids are the main bioactive constituents. Localization and quantification of CNS drugs in fine brain regions are important to provide insights into their pharmacodynamics, for which quantitative mass spectrometry imaging (MSI) has emerged as a powerful technique. A systematic study of the quantitative imaging of seven Uncaria alkaloids in rat brains using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was presented. The distribution of the alkaloids in thirteen brain regions was quantified successfully using the calibration curves generated by a modified on-tissue approach. The distribution trend of different Uncaria alkaloids in the rat brain was listed as monoterpene indole alkaloids > monoterpene oxindole alkaloids, R-configuration epimers > S-configuration epimers. Particularly, Uncaria alkaloids were detected directly in the pineal gland for the first time and their enrichment phenomenon in this region had an instructive significance in future pharmacodynamic studies.

Transcriptome revealing the dual regulatory mechanism of ethylene on the rhynchophylline and isorhynchophylline in Uncaria rhynchophylla

Rhynchophylline (RIN) and isorhynchophylline (IRN) are extracted from Uncaria rhynchophylla, which are used to treat Alzheimer's disease. However, the massive accumulation of RIN and IRN in U. rhynchophylla requires exogenous stimulation. Ethylene is a potential stimulant for RIN and IRN biosynthesis, but there is no study on the role of ethylene in RIN or IRN synthesis. This study investigated the regulation of ethylene in RIN and IRN biosynthesis in U. rhynchophylla. An increase in the content of RIN and IRN was observed that could be attributed to the release of ethylene from 18 mM ethephon, while ethylene released from 36 mM ethephon reduced the content of RIN and IRN. The transcriptome and weighted gene co-expression network analysis indicated the up-regulation of seven key enzyme genes related to the RIN/IRN biosynthesis pathway and starch/sucrose metabolism pathway favored RIN/IRN synthesis. In comparison, the down-regulation of these seven key enzyme genes contributed to the reduction of RIN/IRN. Moreover, the inhibition of photosynthesis is associated with a reduction in RIN/IRN. Photosynthesis was restrained owing to the down-regulation of Lhcb1 and Lhcb6 after 36 mM ethephon treatment and further prevented supply of primary metabolites (such as α-D-glucose) for RIN/IRN synthesis. However, uninterrupted photosynthesis ensured a normal supply of primary metabolites at 18 mM ethephon treatment. AP2/ERF1, bHLH1, and bHLH2 may positively regulate the RIN/IRN accumulation, while NAC1 may play a negative regulatory role. Our results construct the potential bidirectional model for ethylene regulation on RIN/IRN synthesis and provide novel insight into the ethylene-mediated regulation of the metabolism of terpenoid indole alkaloids.

Dendrobium nobile Lindl. Alkaloids Ameliorate Aβ25-35-Induced Synaptic Deficits by Targeting Wnt/β-Catenin Pathway in Alzheimer’s Disease Models

Background: Dendrobium nobile Lindl. alkaloids (DNLA) are effective in ameliorating cognitive deficit in SAMP8, AβPP/PS1, and LPS-induced AD animal models, and prevented Aβ-induced synaptic degeneration in cultured hippocampal neurons. However, the underlying mechanisms remain unexplored. Objective: This study investigated the protective effects of DNLA on synaptic damage in an Aβ 25-35-induced rat AD model, in primary cortical neuron cultures, and in PC12 cells transfected with human AβPP695, focusing on the Wnt/β-catenin pathway. Methods: Sprague-Dawley rats received a single Aβ 25-35 injection (10μg) into the bilateral hippocampi. DNLA (40 and 80 mg/kg/d) was intragastrically administrated 7d prior to Aβ injection and continued for 28 days. The spatial learning and memory, synaptic morphology, synapse-related proteins, and Wnt signaling components GSK3β and β-catenin phosphorylation were evaluated. Rat primary cortical neuron cultures and AβPP695-PC12 cells were used to evaluate axonal mitochondria distribution, reactive oxygen species production, amyloidogenesis, and Wnt pathway in the protection. Results: DNLA ameliorated Aβ-induced cognitive impairment, increased the number of synapses, elevated the postsynaptic density thickness and expression of synapsin and PSD95 in the hippocampus, and suppressed Aβ-mediated GSK3β activity and the β-catenin phosphorylation. In primary neurons and AβPP695-PC12 cells, DNLA restored Aβ 25-35 induced mitochondrial dysfunction and inhibited reactive oxygen species production and amyloidogenesis. Furthermore, the Wnt/β-catenin pathway inhibitor Dkk-1 blocked the effect of DNLA on the expression of Aβ 1-42 and PSD95. Conclusion: DNLA rescued Aβ-mediated synaptic and mitochondrial injury and inhibited amyloidogenesis in vivo and in vitro, probably through the activation of Wnt/β-catenin signaling pathway to protect synaptic integrity.

The Study of the Transport Mechanism of Isorhynchophylline in Liver

To investigate the transport mechanism of isorhynchophylline (IRN) by using the specific inhibitors of organic cation transporters (OCTs) and organic anion transporting polypeptides (OATPs) and attempt illustrate the metabolic mechanism of IRN in the liver. All animals were randomly divided into three groups: control group (only inject IRN), RIF group (inject IRN and rifampicin), and ADR group (inject IRN and adrenalone). The control group was injected with IRN via the caudal vein. The RIF group was injected with rifampicin (RIF) by gavage, and after 1 h, IRN was injected into the caudal vein. Similarly, the ADR group received adrenalone by the caudal vein, and after 0.5 h, IRN was injected into the caudal vein. Thereafter, blood samples were obtained by the heart punctures at 90 min, 180 min, and 300 min following drug administration. Rats were sacrificed at 300 min after drug administration; then, the liver tissue was harvested. The level of IRN was measured by using high-performance liquid chromatography (HPLC), and the Kp values were calculated. After RIF administration (OATPs inhibitors), the Kp value of IRN was slightly decreased when compared with that of the control group. Meanwhile, the Kp value of IRN was dramatically reduced compared to that of the control group following ADR administration (OCTs inhibitors). The results suggested that OCTs have mainly participated in the hepatic uptake process of IRN.

Nano-Honokiol ameliorates the cognitive deficits in TgCRND8 mice of Alzheimer's disease via inhibiting neuropathology and modulating gut microbiota

Introduction

Honokiol (HO) exerts neuroprotective effects in several animal models of Alzheimer's disease (AD), but the poor dissolution hampers its bioavailability and therapeutic efficacy.

Objectives

A novel honokiol nanoscale drug delivery system (Nano-HO) with smaller size and excellent stability was developed in this study to improve the solubility and bioavailability of HO. The anti-AD effects of Nano-HO was determined.

Methods

Male TgCRND8 mice were daily orally administered Nano-HO or HO at the same dosage (20 mg/kg) for 17 consecutive weeks, followed by assessment of the spatial learning and memory functions using the Morris Water Maze test (MWMT).

Results

Our pharmacokinetic study indicated that the oral bioavailability was greatly improved by Nano-HO. In addition, Nano-HO significantly improved cognitive deficits and inhibited neuroinflammation via suppressing the levels of TNF-α, IL-6 and IL-1β in the brain, preventing the activation of microglia (IBA-1) and astrocyte (GFAP), and reducing β-amyloid (Aβ) deposition in the cortex and hippocampus of TgCRND8 mice. Moreover, Nano-HO was more effective than HO in modulating amyloid precursor protein (APP) processing via suppressing β-secretase, as well as enhancing Aβ-degrading enzymes like neprilysin (NEP). Furthermore, Nano-HO more markedly inhibited tau hyperphosphorylation via decreasing the ratio of p-Tau (Thr 205)/tau and regulating tau-related apoptosis proteins (caspase-3 and Bcl-2). In addition, Nano-HO more markedly attenuated the ratios of p-JNK/JNK and p-35/CDK5, while enhancing the ratio of p-GSK-3β (Ser9)/GSK-3β. Finally, Nano-HO prevented the gut microflora dysbiosis in TgCRND8 mice in a more potent manner than free HO.

Conclusion

Nano-HO was more potent than free HO in improving cognitive impairments in TgCRND8 mice via inhibiting Aβ deposition, tau hyperphosphorylation and neuroinflammation through suppressing the activation of JNK/CDK5/GSK-3β signaling pathway. Nano-HO also more potently modulated the gut microbiota community to protect its stability than free HO. These results suggest that Nano-HO has good potential for further development into therapeutic agent for AD treatment.

Roles of traditional chinese medicine regulating neuroendocrinology on AD treatment

The incidence of sporadic Alzheimer's disease (AD) is increasing in recent years. Studies have shown that in addition to some genetic abnormalities, the majority of AD patients has a history of long-term exposure to risk factors. Neuroendocrine related risk factors have been proved to be strongly associated with AD. Long-term hormone disorder can have a direct detrimental effect on the brain by producing an AD-like pathology and result in cognitive decline by impairing neuronal metabolism, plasticity and survival. Traditional Chinese Medicine(TCM) may regulate the complex process of endocrine disorders, and improve metabolic abnormalities, as well as the resulting neuroinflammation and oxidative damage through a variety of pathways. TCM has unique therapeutic advantages in treating early intervention of AD-related neuroendocrine disorders and preventing cognitive decline. This paper reviewed the relationship between neuroendocrine and AD as well as the related TCM treatment and its mechanism. The advantages of TCM intervention on endocrine disorders and some pending problems was also discussed, and new insights for TCM treatment of dementia in the future was provided.

Tieguanyin Oolong Tea Extracts Alleviate Behavioral Abnormalities by Modulating Neuroinflammation in APP/PS1 Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a common neurodegenerative disease; tea components have important neuroprotective effects. This article explores the effects and mechanisms of Qingxiang Tiguanyin (Tgy-Q), Nongxiang Tieguanyin (Tgy-N), and Chenxiang Tieguanyin (Tgy-C) extracts on APP/PS1 AD model mice. Morris water maze and new object recognition experiments show that Tieguanyin extracts can effectively enhance the cognitive ability of APP/PS1 mice. H&E staining, Nissl staining, and immunohistochemical staining show that Tieguanyin extracts make nerve cell boundaries and nucleoli become clearer, relieve nucleus pyknosis, and effectively reduce Aβ1-40 and Aβ1-42 in the hippocampus and cortex. They also restore the morphology of microglia and astrocytes. In addition, Tieguanyin extracts can balance the oxidative stress level in the brain of APP/PS1 mice by improving the antioxidant capacity. Western blot results show that Tieguanyin extracts can reduce the expression of NF-κB p65, TNF-α, IL-1β, IL-6, COX-2, and iNOS in mouse brain, which demonstrates that Tieguanyin extracts improves cognitive ability by alleviating inflammation. This article demonstrates for the first time that Tieguanyin extracts can inhibit the excessive activation of the NF-κB p65 signaling pathway and improve the antioxidant capacity in the cerebral cortex and hippocampus, to improve the cognitive ability of APP/PS1 mice. Our results shed light into the beneficial of Tieguanyin tea extracts on preventing and alleviating AD diseases.

Rhynchophylline Administration Ameliorates Amyloid-β Pathology and Inflammation in an Alzheimer's Disease Transgenic Mouse Model

Alzheimer's disease (AD), the most common neurodegenerative disease, has limited treatment options. As such, extensive studies have been conducted to identify novel therapeutic approaches. We previously reported that rhynchophylline (Rhy), a small molecule EphA4 inhibitor, rescues impaired hippocampal synaptic plasticity and cognitive dysfunctions in APP/PS1 mice, an AD transgenic mouse model. To assess whether Rhy can be developed as an alternative treatment for AD, it is important to examine its pharmacokinetics and effects on other disease-associated pathologies. Here, we show that Rhy ameliorates amyloid plaque burden and reduces inflammation in APP/PS1 mice. Transcriptome analysis revealed that Rhy regulates various molecular pathways in APP/PS1 mouse brains associated with amyloid metabolism and inflammation, specifically the ubiquitin proteasome system, angiogenesis, and microglial functional states. These results show that Rhy, which is blood-brain barrier permeable, is beneficial to amyloid pathology and regulates multiple molecular pathways.

Comparison of the chemical constituents and anti-Alzheimer's disease effects of Uncaria rhynchophylla and Uncaria tomentosa

BACKGROUND

Uncaria tomentosa, which has similar chemical constituents with Uncaria rhynchophylla, has been reported to alleviate cognitive impairments in Alzheimer's disease (AD) animal models. This study aimed to compare the chemical constituents and anti-AD effect of the ethanol extracts of U. tomentosa (UTE) and U. rhynchophylla (URE).

METHODS

The high-performance liquid chromatography (HPLC) was used to compare the chemical constituents of UTE and URE. Streptozotocin (STZ) was intracerebroventricularly (ICV) injected into adult male Sprague-Dawley (SD) rats to establish AD model. UTE (400 mg/kg) or URE (400 mg/kg) was administrated intragastrically once daily to the rats for 6 consecutive weeks. Morris water maze (MWM) test was conducted to assess the neurological functions in the STZ-induced AD rats. The brain tissues of the rats were harvested for further biochemical assay.

RESULTS

The MWM test results showed both UTE and URE could significantly improve the learning and memory impairments induced by STZ in rats. Both UTE and URE could significantly inhibit the hyperphosphorylation of tau protein, reduce the elevated levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), enhance activities of antioxidant enzymes (SOD, CAT and GPx) and increase the protein expression of HO-1. In addition, UTE could decrease the malondialdehyde (MDA) level. Furthermore, both UTE and URE significantly enhanced Akt activation, down regulated the activation of glycogen synthase kinase 3β (GSK-3β), and induced the nuclear translocation of Nrf2 in the STZ-induced AD rats.

CONCLUSIONS

UTE and URE contained similar chemical constituents. We found for the first time that both of them could ameliorate cognitive deficits in the STZ-induced AD rats. The underlying molecular mechanism involve suppression of tau hyperphosphorylation, anti-oxidant and anti-neuroinflammation via modulating Akt (Ser473)/GSK3β (Ser9)-mediated Nrf2 activation. These findings amply implicate that both of UTE and URE are worthy of being developed clinically into pharmaceutical treatment for AD.

Treatment with 5-fluoro-2-oxindole Increases the Antinociceptive Effects of Morphine and Inhibits Neuropathic Pain

The efficacy of µ-opioid receptors (MOR) in neuropathic pain is low and with numerous side effects that limited their use. Chronic neuropathic pain is also linked with emotional disorders that aggravate the sensation of pain and which treatment has not been resolved. This study investigates whether the administration of an oxindole, 5-fluoro-2-oxindole, could inhibit the nociceptive and emotional behaviors and increase the effectiveness of morphine via modulating the microglia and activating the nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway and MOR expression. In C57BL/6 mice with neuropathic pain provoked by the total constriction of sciatic nerve we studied the effects of 10 mg/kg 5-fluoro-2-oxindole in: (i) the allodynia and hyperalgesia caused by the injury; (ii) the anxiety- and depressive-like behaviors; (iii) the local antinociceptive actions of morphine; (iv) the expression of CD11b/c (a microglial marker), the antioxidant and detoxificant enzymes Nrf2, heme oxygenase 1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO1), and of MOR in the spinal cord and hippocampus. Results showed that the inhibition of the main nociceptive symptoms and the anxiety- and depressive-like behaviors induced by 5-fluoro-2-oxindole were accompanied with the suppression of microglial activation and the activation of Nrf2/HO-1/NQO1 signaling pathway in the spinal cord and/or hippocampus. This treatment also potentiated the pain-relieving activities of morphine by normalizing the reduced MOR expression. This work demonstrates the antinociceptive, anxiolytic and antidepressant effects of 5-fluoro-2-oxindole, suggests a new strategy to enhance the antinociceptive actions of morphine and proposes a new mechanism of action of oxindoles during chronic neuropathic pain.

Cerebralcare Granule® enhances memantine hydrochloride efficacy in APP/PS1 mice by ameliorating amyloid pathology and cognitive functions

Background

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by memory deficits and cognitive decline. Current drugs can only relieve symptoms, but cannot really cure AD. Cerebralcare Granule® (CG) is a Traditional Chinese medicine (TCM) containing a variety of biologically active compounds. In our previous studies, CG has shown a beneficial effect against memory impairment in mice caused by d-galactose. However, whether CG can be used as a complementary medicine for the treatment of AD remains unexplored. Here, we use a combination of CG and memantine hydrochloride (Mm) to treat Alzheimer-like pathology and investigate the effects and mechanisms in vivo.

Methods

The histology of brain was examined with Hematoxylin–eosin (HE) staining, Golgi staining and Thioflavin S staining. ELISA was applied to assess the expression levels or activities of CAT, SOD, GSH-Px, MDA, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL) in serum, as well as the levels of IL-6, IL-1β, and TNF-α in the mice brain. Western blotting was used to assess the expression of β-secretase (BACE1), amyloid precursor protein (APP), APPβ, APPα, synaptophysin (SYN), growth-associated protein 43 (GAP43), and postsynaptic density 95 (PSD95).

Results

In the present study, the combination group (CG + Mm) significantly attenuated Alzheimer-like behavior without adverse effects in APP/PS1 mice, indicating its high degree of safety and efficacy after long-term treatment. CG + Mm reduced AD pathological biomarker Aβ plaque accumulation by inhibiting BACE1 and APP expression (P < 0.05 or P < 0.001). Besides, the combination group markedly inhibited the levels of IL-1β, IL-6, and TNF-α in hippocampus (P < 0.001), as well as activities of SOD, CAT, and GSH-Px in serum (P < 0.001). By contrast, the combination group improved synaptic plasticity by enhancing SYN, PSD95, and GAP43 expression.

Conclusions

Taken together, these data supported the notion that CG combined with Mm might ameliorate the cognitive impairment through multiple pathways, suggesting that CG could play a role as complementary medicine to increase anti-AD effect of chemical drugs by reducing Aβ deposition, neuroinflammation, oxidative damage, and improving synaptic plasticity.

The Main Alkaloids in Uncaria rhynchophylla and Their Anti-Alzheimer's Disease Mechanism Determined by a Network Pharmacology Approach

Alzheimer's disease (AD) is a growing concern in modern society, and effective drugs for its treatment are lacking. Uncaria rhynchophylla (UR) and its main alkaloids have been studied to treat neurodegenerative diseases such as AD. This study aimed to uncover the key components and mechanism of the anti-AD effect of UR alkaloids through a network pharmacology approach. The analysis identified 10 alkaloids from UR based on HPLC that corresponded to 90 anti-AD targets. A potential alkaloid target-AD target network indicated that corynoxine, corynantheine, isorhynchophylline, dihydrocorynatheine, and isocorynoxeine are likely to become key components for AD treatment. KEGG pathway enrichment analysis revealed the Alzheimers disease (hsa05010) was the pathway most significantly enriched in alkaloids against AD. Further analysis revealed that 28 out of 90 targets were significantly correlated with Aβ and tau pathology. These targets were validated using a Gene Expression Omnibus (GEO) dataset. Molecular docking studies were carried out to verify the binding of corynoxine and corynantheine to core targets related to Aβ and tau pathology. In addition, the cholinergic synapse (hsa04725) and dopaminergic synapse (hsa04728) pathways were significantly enriched. Our findings indicate that UR alkaloids directly exert an AD treatment effect by acting on multiple pathological processes in AD.

Isorhynchophylline Ameliorates Cerebral Ischemia/Reperfusion Injury by Inhibiting CX3CR1-Mediated Microglial Activation and Neuroinflammation

Reperfusion therapy is an effective way to rescue cerebral ischemic injury, but this therapy also shows the detrimental risk of devastating disorders and death due to the possible inflammatory responses involved in the pathologies. Hence, the therapy of ischemia/reperfusion (I/R) injury is a great challenge currently. Isorhynchophylline (IRN), a tetracyclic oxindole alkaloid extracted from Uncaria rhynchophylla, has previously shown neuroprotective and anti-inflammatory effects in microglial cells. This study systematically investigates the effect of IRN on I/R injury and its underlying mechanism. The effects of IRN on neuronal injury and microglia-mediated inflammatory response were assessed on a rat model with middle cerebral artery occlusion (MCAO) and reperfusion-induced injury. We found that IRN treatment attenuated the infarct volume and improved the neurological function in I/R injury rats. IRN treatment also reduced the neuronal death rate, brain water content, and aquaporin-4 expression in the ischemic penumbra of I/R injury rats’ brains. Besides, IRN treatment could inhibit the following process, including IκB-α degradation, NF-κB p65 activation, and CX3CR1 expression, as well as the microglial activation and inflammatory response. These findings suggest that IRN is a promising candidate to treat the cerebral I/R injury via inhibiting microglia activation and neuroinflammation.

Suan-Zao-Ren Decoction ameliorates synaptic plasticity through inhibition of the Aβ deposition and JAK2/STAT3 signaling pathway in AD model of APP/PS1 transgenic mice

Background

Suan-Zao-Ren Decoction (SZRD) has been widely used to treat neurological illnesses, including dementia, insomnia and depression. However, the mechanisms underlying SZRD’s improvement in cognitive function remain unclear. In this study, we examined SZRD’s effect on APP/PS1 transgenic mice and mechanisms associated with SZRD’s action in alleviating neuroinflammation and improving synaptic plasticity.

Methods

The APP/PS1 mice were treated with different dosages of SZRD (12.96 and 25.92 g/kg/day, in L-SZRD and H-SZRD groups, respectively) for 4 weeks. Morris water maze was conducted to determine changes in behaviors of the mice after the treatment. Meanwhile, in the samples of the hippocampus, Nissl staining and Golgi-Cox staining were used to detect synaptic plasticity. ELISA was applied to assess the expression levels of Aβ₁₋₄₀ and Aβ₁₋₄₂ in the hippocampus of mice. Western blot (WB) was employed to test the protein expression level of Aβ₁₋₄₂, APP, ADAM10, BACE1, PS1, IDE, IBA1, GFAP, PSD95 and SYN, as well as the expressions of JAK2, STAT3 and their phosphorylation patterns to detect the involvement of JAK2/STAT3 pathway. Besides, we examined the serum and hippocampal contents of IL-1β, IL-6 and TNF-α through ELISA.

Results

Compared to the APP/PS1 mice without any treatment, SZRD, especially the L-SZRD, significantly ameliorated cognitive impairment of the APP/PS1 mice with decreases in the loss of neurons and Aβ plaque deposition as well as improvement of synaptic plasticity in the hippocampus (P < 0.05 or 0.01). Also, SZRD, in particular, the L-SZRD markedly inhibited the serum and hippocampal concentrations of IL-6, IL-1β and TNF-α, while reducing the expression of p-JAK2-Tyr1007 and p-STAT3-Tyr705 in the hippocampus of the APP/PS1 mice (P < 0.05 or 0.01).

Conclusions

The SZRD, especially the L-SZRD, may improve the cognitive impairment and ameliorate the neural degeneration in APP/PS1 transgenic mice through inhibiting Aβ accumulation and neuroinflammation via the JAK2/STAT3 pathway.

The Antinociceptive, Antioxidant and Anti-Inflammatory Effects of 5-Fluoro-2-Oxindole during Inflammatory Pain

Recent studies demonstrate that 5-fluoro-2-oxindole inhibits neuropathic pain but the antinociceptive actions of this drug and its effects on the plasticity, oxidative and inflammatory changes induced by peripheral inflammation as well as on the effects and expression of µ-opioid receptors (MOR) have not been evaluated. In C57BL/6 male mice with inflammatory pain provoked by the subplantar administration of complete Freund’s adjuvant (CFA), we evaluated: (1) the antinociceptive actions of 5-fluoro-2-oxindole and its reversion with the HO-1 inhibitor, tin protoporphyrin IX (SnPP); (2) the effects of 5-fluoro-2-oxindole in the protein levels of mitogen-activated protein kinase (MAPK), Nrf2, NADPH quinone oxidoreductase1 (NQO1), heme oxygenase 1 (HO-1), oxidative stress marker (4-hydroxy-2-nonenal; 4-HNE), inducible nitric oxide synthase (NOS2), microglial markers (CD11b/c and IBA-1), and MOR in the spinal cord and/or paw of animals with inflammatory pain; (3) the antinociceptive effects of morphine in 5-fluoro-2-oxindole pre-treated animals. Treatment with 5 and 10 mg/kg of 5-fluoro-2-oxindole inhibited the allodynia and hyperalgesia induced by CFA in a different, time-dependent manner. These effects were reversed by SnPP. Treatment with 5-fluoro-2-oxindole increased the expression of NQO1, HO-1 and MOR and inhibited the CFA-induced upregulation of phosphorylated MAPK, 4-HNE, NOS2, CD11b/c and IBA-1 in spinal cords and/or paws. The local effects of morphine were improved with 5-fluoro-2-oxindole. This work reveals that 5-fluoro-2-oxindole inhibits the plasticity, oxidative and inflammatory responses provoked by peripheral inflammation and potentiates the antinociceptive effects of morphine. Thus, treatment with 5-fluoro-2-oxindole alone and/or combined with morphine are two remarkable new procedures for chronic inflammatory pain management.

Uncaria rhynchophylla and its Major Constituents on Central Nervous System: A Review on Their Pharmacological Actions

BACKGROUND

Uncaria rhynchophylla (Miq.) Jacks (Rubinaceae), a common herbal medicine known as Gou-teng in Chinese, is commonly used in Chinese medicine practice for the treatment of convulsions, hypertension, epilepsy, eclampsia and other cerebral diseases. The major active components of U. rhynchophylla are alkaloids, terpenoids and flavonoids. The protective effects of U. rhynchophylla and its major components on central nervous system (CNS) have become a focus of research in recent decades.

OBJECTIVE

The study aimed to systematically summarize the pharmacological activities of U. rhynchophylla and its major components on the CNS.

METHODS

This review summarized the experimental findings from our laboratories, together with other literature data obtained through a comprehensive search of databases including the Pubmed and the Web of Science.

RESULTS

U. rhynchophylla and its major components such as rhynchophylline and isorhynchophylline have been shown to have neuroprotective effects on Alzheimer's disease, Parkinson's disease, depression, cerebral ischaemia through a number of mechanisms including anti-oxidant, anti-inflammatory actions and regulation on neurotransmitters.

CONCLUSION

U. rhynchophylla and its major components have multiple beneficial pharmacological effects on CNS. Further studies on U. rhynchophylla and its major components are warranted to fully illustrate the underlying molecular mechanisms, pharmacokinetics, and toxicological profiles of these naturally occurring compounds and their potential for clinical application.

Recent research progress of Uncaria spp. based on alkaloids: phytochemistry, pharmacology and structural chemistry

Medicinal plants are well-known in affording clinically useful agents, with rich medicinal values by combining with disease targets through various mechanisms. Plant secondary metabolites as lead compounds lay the foundation for the discovery and development of new drugs in disease treatment. Genus Uncaria from Rubiaceae family is a significant plant source of active alkaloids, with anti-hypertensive, sedative, anti-Alzheimer's disease, anti-drug addiction and anti-inflammatory effects. This review summarizes and discuss the research progress of Uncaria based on alkaloids in the past 15 years, mainly in the past 5 years, including biosynthesis, phytochemistry, pharmacology and structural chemistry. Among, focusing on representative compounds rhynchophylline and isorhynchophylline, the pharmacological activities surrounding the central nervous system and cardiovascular system are described in detail. On the basis of case studies, this article provides a brief overview of the synthesis and analogues of representative compounds types. In summary, this review provides an early basis for further searching for new targets and activities, discussing the mechanisms of pharmacological activity and studying the structure-activity relationships of active molecules.

Magnolol Ameliorates Behavioral Impairments and Neuropathology in a Transgenic Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a common neurodegenerative disease characterized by progressive memory loss. Magnolol (MN), the main active ingredient of Magnolia officinalis, possesses anti-AD effects in several experimental models of AD. In this study, we aimed to explore whether MN could ameliorate the cognitive deficits in TgCRND8 transgenic mice and to elucidate its molecular mechanisms. Male TgCRND8 mice were orally administered with MN (20 and 40 mg/kg) daily for 4 consecutive months, followed by assessing the spatial learning and memory functions using the open-field, radial arm maze, and novel object recognition tests. The results demonstrated that MN (20 and 40 mg/kg) could markedly ameliorate the cognitive deficits in TgCRND8 mice. In addition, MN significantly increased the expression of postsynaptic density protein 93 (PSD93), PSD-95, synapsin-1, synaptotagmin-1, synaptophysin (SYN), and interleukin-10 (IL-10), while markedly reduced the protein levels of tumor necrosis factor alpha (TNF-α), IL-6, IL-1β, Aβ₄₀, and Aβ₄₂, and modulated the amyloid precursor protein (APP) processing and phosphorylation. Immunofluorescence showed that MN significantly suppressed the activation of microglia (Iba-1) and astrocytes (GFAP) in the hippocampus and cerebral cortex of TgCRND8 mice. Mechanistic studies revealed that MN could significantly increase the ratios of p-GSK-3β (Ser9)/GSK-3β, p-Akt (Ser473)/Akt, and p-NF-κB p65/NF-κB p65. These findings indicate that MN exerted cognitive deficits improving effects via suppressing neuroinflammation, amyloid pathology, and synaptic dysfunction through regulating the PI3K/Akt/GSK-3β and NF-κB pathways, suggesting that MN is a promising naturally occurring polyphenol worthy of further developing into a therapeutic agent for AD treatment.

Lemon essential oil ameliorates age-associated cognitive dysfunction via modulating hippocampal synaptic density and inhibiting acetylcholinesterase

The lemon essential oil (LEO), extracted from the fruit of lemon, has been used to treat multiple pathological diseases, such as diabetes, inflammation, cardiovascular diseases, depression and hepatobiliary dysfunction. The study was designed to study the effects of LEO on cognitive dysfunction induced by Alzheimer’s disease (AD). We used APP/PS1 double transgene (APP/PS1) AD mice in the experiment; these mice exhibit significant deficits in synaptic density and hippocampal-dependent spatial related memory. The effects of LEO on learning and memory were examined using the Morris Water Maze (MWM) test, Novel object recognition test, and correlative indicators, including a neurotransmitter (acetylcholinesterase, AChE), a nerve growth factor (brain-derived neurotrophic factor, BDNF), a postsynaptic marker (PSD95), and presynaptic markers (synapsin-1, and synaptophysin), in APP/PS1 mice. Histopathology was performed to estimate the effects of LEO on AD mice. A significantly lowered brain AChE depression in APP/PS1 and wild-type C57BL/6L (WT) mice. PSD95/ Synaptophysin, the index of synaptic density, was noticeably improved in histopathologic changes. Hence, it can be summarized that memory-enhancing activity might be associated with a reduction in the AChE levels and is elevated by BDNF, PSD95, and synaptophysin through enhancing synaptic plasticity.

A Network-Based Approach to Explore the Mechanisms of Uncaria Alkaloids in Treating Hypertension and Alleviating Alzheimer's Disease

Uncaria alkaloids are the major bioactive chemicals found in the Uncaria genus, which have a long history of clinical application in treating cardiovascular and mental diseases in traditional Chinese medicine (TCM). However, there are gaps in understanding the multiple targets, pathways, and biological activities of Uncaria alkaloids. By constructing the interactions among drug-targets-diseases, network pharmacology provides a systemic methodology and a novel perspective to present the intricate connections among drugs, potential targets, and related pathways. It is a valuable tool for studying TCM drugs with multiple indications, and how these multi-indication drugs are affected by complex interactions in the biological system. To better understand the mechanisms and targets of Uncaria alkaloids, we built an integrated analytical platform based on network pharmacology, including target prediction, protein-protein interaction (PPI) network, topology analysis, gene enrichment analysis, and molecular docking. Using this platform, we revealed the underlying mechanisms of Uncaria alkaloids' anti-hypertensive effects and explored the possible application of Uncaria alkaloids in preventing Alzheimer's disease. These results were further evaluated and refined using biological experiments. Our study provides a novel strategy for understanding the holistic pharmacology of TCM, as well as for exploring the multi-indication properties of TCM beyond its traditional applications.