Beta-asarone attenuates amyloid beta-induced autophagy via Akt/mTOR pathway in PC12 cells

Volatile oil of Acori tatarinowii rhizoma: potential candidate drugs for mitigating dementia

Objective

This study aims to elucidate the mitigating effects of the volatile oil of Acori tatarinowii rhizoma (ATR) on dementia, in order to provide a reference for future research and applications of the volatile oil of ATR in the field of dementia.

Materials and methods

A search strategy was developed using terms such as "Acori tatarinowii rhizoma," "Acorus tatarinowii Schott," "Asarone," and "Dementia." The literature search was conducted in PubMed, Web of Science, and Google Scholar, and studies not meeting the inclusion criteria were excluded. This study summarizes the main metabolites, active ingredients, toxicological properties, and pharmacokinetic characteristics of the volatile oil from ATR in mitigating dementia, with a particular focus on its potential mechanisms of action. Furthermore, the study highlights the limitations of existing research and offers insights into future research directions.

Results

The volatile oil of ATR mitigates dementia through multiple pathways, including reducing abnormal protein aggregation, promoting neurogenesis, inhibiting neuronal apoptosis, regulating neurotransmitters, improving synaptic function, modulating autophagy, countering cellular stress, reducing neuroinflammation, and alleviating vascular risk factors.

Conclusion

The multi-pathway pharmacological effects of the volatile oil of ATR are well-aligned with the complex mechanisms of dementia progression, highlighting its significant therapeutic potential for anti-dementia applications. This provides new perspectives for the development of more effective anti-dementia drugs. Nonetheless, further rigorous and high-quality preclinical and clinical investigations are required to address key issues, including the chemical characterization of the volatile oil of ATR, potential synergistic effects among active ingredients, toxicity profiles, and definitive clinical efficacy.

Anti-inflammatory compounds from the rhizome of Acorus calamus var. angustatus Besser and their mechanism

Seven compounds, named β-sitosterol (1), daucosterol (2), (+)-pinoresinol-β-D-glucoside (3), (-)-syringaresinol 4-O-β-D-apiofuranosyl-(1→2)- β-D-glucopyranoside (4), 4-hydroxybenzoic acid (5), 2-(3', 4'-dihydroxyphenyl)-1, 3-pepper ring-5-aldehyde (6) and spinosin (7) were isolated from the rhizome of Acorus calamus var. angustatus Besser. 3, 4, 6 and 7 were isolated from this medicinal plant for the first time. Structures were elucidated by physicochemical properties and extensive spectroscopic analysis, as well as by comparison with literature data. The anti-inflammatory activity and related mechanisms of the seven compounds showed that compounds 1-7 all increased the levels of GSH-PX and SOD and decreased the levels of MDA, TNF-α, IL-1β and IL-6. Compound 4 showed the best effect of anti-inflammatory and Beclin-1 inhibition. These results suggest that compound 4 has stronger anti-inflammatory effect and provide preliminary evidence that the mechanism of action of compound 4 in attenuating LPS-induced inflammatory damage may be related to the inhibition of Beclin-1-dependent autophagy.

Therapeutic Effects of the major alkaloid constituents of Evodia rutaecarpa in Alzheimer's disease

Since the report of Alzheimer's disease (AD) in 1907, it has garnered widespread attention due to its intricate pathogenic mechanisms, significant impact on patients' lives, and the substantial burden it places on society. Presently, effective treatments for AD remain elusive. Recent pharmacological studies on the traditional East Asian herb, Evodia rutaecarpa, have revealed that the bioactive alkaloid components within it can ameliorate AD-related cognitive impairments and neurological damage through various pathways, including anti-inflammatory, antioxidant, and anti-acetylcholinesterase activities. Consequently, this article provides an overview of the pharmacological effects and research status of the four main alkaloid components found in Evodia concerning AD. We hope this article will serve as a valuable reference for experimental and clinical research on the use of Evodia in AD prevention and treatment.

Therapeutic potential of natural products against Alzheimer's disease via autophagic removal of Aβ

The pathological features of Alzheimer's disease (AD), a progressive neurodegenerative disorder, include the deposition of extracellular amyloid beta (Aβ) plaques and intracellular tau neurofibrillary tangles. A decline in cognitive ability is related to the accumulation of Aβ in patients with AD. Autophagy, which is a primary intracellular mechanism for degrading aggregated proteins and damaged organelles, plays a crucial role in AD. In this review, we summarize the most recent research progress regarding the process of autophagy and the effect of autophagy on Aβ. We further discuss some typical monomers of natural products that contribute to the clearance of Aβ by autophagy, which can alleviate AD. This provides a new perspective for the application of autophagy modulation in natural product therapy for AD.

Ethnic, Botanic, Phytochemistry and Pharmacology of the Acorus L. Genus: A Review

The genus Acorus, a perennial monocotyledonous-class herb and part of the Acoraceae family, is widely distributed in the temperate and subtropical zones of the Northern and Southern Hemispheres. Acorus is rich in biological activities and can be used to treat various diseases of the nervous system, cardiovascular system, and digestive system, including Alzheimer's disease, depression, epilepsy, hyperlipidemia, and indigestion. Recently, it has been widely used to improve eutrophic water and control heavy-metal-polluted water. Thus far, only three species of Acorus have been reported in terms of chemical components and pharmacological activities. Previously published reviews have not further distinguished or comprehensively expounded the chemical components and pharmacological activities of Acorus plants. By carrying out a literature search, we collected documents closely related to Acorus published from 1956 to 2022. We then performed a comprehensive and systematic review of the genus Acorus from different perspectives, including botanical aspects, ethnic applications, phytochemistry aspects, and pharmacological aspects. Our aim was to provide a basis for further research and the development of new concepts.

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

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

Recent Advancements in Nanocarrier-assisted Brain Delivery of Phytochemicals Against Neurological Diseases

Despite ongoing advancements in research, the inability of therapeutics to cross the blood-brain barrier (BBB) makes the treatment of neurological disorders (NDs) a challenging task, offering only partial symptomatic relief. Various adverse effects associated with existing approaches are another significant barrier that prompts the usage of structurally diverse phytochemicals as preventive/therapeutic lead against NDs in preclinical and clinical settings. Despite numerous beneficial properties, phytochemicals suffer from poor pharmacokinetic profile which limits their pharmacological activity and necessitates the utility of nanotechnology for efficient drug delivery. Nanocarriers have been shown to be proficient carriers that can enhance drug delivery, bioavailability, biocompatibility, and stability of phytochemicals. We, thus, conducted a meticulous literature survey using several electronic databases to gather relevant studies in order to provide a comprehensive summary about the use of nanocarriers in delivering phytochemicals as a treatment approach for NDs. Additionally, the review highlights the mechanisms of drug transport of nanocarriers across the BBB and explores their potential future applications in this emerging field.

Synergetic effect of β-asarone and cannabidiol against Aβ aggregation in vitro and in vivo

Alzheimer's disease (AD) is a complex and multifactorial neurodegenerative disorder, and it is unlikely that any single drug or intervention will be very successful. The pathophysiology of Alzheimer's disease involves a range of complicated biological processes, including the accumulation of beta-amyloid protein and tau protein. Given the complexity of AD and amyloid accumulation, a combination of interventions remains to be further explored. Here, we investigated the potential of combining β-asarone and cannabidiol (CBD) as a treatment for AD. The study analyzed the combined effects of these two phytochemicals on beta-amyloid (Aβ) protein aggregation and toxicity in bulk solution, in cells as well as in C.elegans. We detailed the morphological and size changes of Aβ40 aggregates in the presence of β-asarone and cannabidiol. More importantly, the presence of both compounds synergistically inhibited apoptosis and downregulated relative gene expression in cells, and that it may also slow aging, decrease the rate of paralysis, enhance learning capacity, and boost autophagy activity in C.elegans. Our studies suggest that multiple drugs, like β-asarone and CBD, may be potentially developed as a medicinal adjunct in the treatment of AD, although further clinical trials are needed to determine the efficacy and safety of this combination treatment in humans.

Acorus calamus var. angustatus Besser: Insight into current research on ethnopharmacological use, phytochemistry, pharmacology, toxicology, and pharmacokinetics

A. calamus var. angustatus Besser is an important traditional medicinal herb commonly used in China and other Asian countries. This study is the first systematic review of the literature to thoroughly analyze the ethnopharmacological application, phytochemistry, pharmacology, toxicology and pharmacokinetic properties of A. calamus var. angustatus Besser and provides a rationale for future research and prospects for application in clinical treatment. Information on relevant studies investigating A. calamus var. angustatus Besser was collected from SciFinder, the Web of Science, PubMed, CNKI, Elsevier, ResearchGate, ACS, Flora of China, and Baidu Scholar, etc. up to December 2022. In addition, information was also obtained from Pharmacopeias, books on Chinese herbal classics, local books, as well as PhD and MS dissertations. A. calamus var. angustatus Besser has played an important role in the herbal treatment of coma, convulsion, amnesia, and dementia for thousands of years. Studies investigating the chemical constituents of A. calamus var. angustatus Besser have isolated and identified 234 small-molecule compounds and a few polysaccharides. Among them, simple phenylpropanoids represented by asarone analogues and lignans are the two main active ingredients, which can be considered characteristic chemotaxonomic markers of this herb. In vitro and in vivo pharmacological studies indicated that crude extracts and active compounds from A. calamus var. angustatus Besser display a wide range of pharmacological activities, especially as treatment for Alzheimer's disease (AD), and anticonvulsant, antidepressant-like, anxiolytic-like, anti-fatigue, anti-Parkinson, neuroprotection, and brain protection properties, providing more evidence to explain the traditional medicinal uses and ethnopharmacology. The clinical therapeutic dose of A. calamus var. angustatus Besser does not present any toxic effects, but its main active ingredients α-asarone and β-asarone at excessive dose may lead to toxicity, and in particular, their respective epoxide metabolites may exert potential toxicity to the liver. This review provides a reference and further information for the future development and clinical application of A. calamus var. angustatus Besser.

Efficacy and safety of herbal medicine on dementia and cognitive function: An umbrella review of systematic reviews and meta-analysis

This study aims to summarize the effects of herbs on dementia and assess the strength of evidence. Six international and local databases were searched from inception to October 2021 for systematic reviews and meta-analyses of clinical trials investigated the effects of herbal medicine on dementia or cognitive function. Two researchers independently extracted data, assessed the methodological quality, and rated the credibility of evidence according to established criteria. Thirty-seven articles evaluating 13 herbal medicines were included. Of these, 65% were rated critically low using AMSTAR2. Of 90 unique outcomes, 41 (45.6%) were statistically significant based on random effects model (p ≤ .05). Only 3 herbs were supported by suggestive evidence whereas the others were supported by weak evidence. The suggestive evidence supported benefits of Chinese herbal medicine (CHM) plus pharmacotherapy (WMD:1.84; 95% CI: 1.34, 2.35) and Vinpocetine (WMD: -0.94; 95%CI: -1.50, -0.38) on improving cognitive function assessing by Montreal Cognitive Assessment and Syndrom-Kurz-Test, respectively. Moreover, suggestive evidence supported benefit of Huperzia serrata on improving Activities of Daily Living (WMD:-7.18; 95%CI: -9.12, -5.23). No SAE was reported. In conclusion, several herbs were used for improving dementia and cognitive function but recent evidence were limited by the small sample size and poor methodological quality. Therefore, further large and well-designed studies are needed to support the evidence.

Natural essential oils derived from herbal medicines: A promising therapy strategy for treating cognitive impairment

Cognitive impairment (CI), mainly Alzheimer’s disease (AD), continues to increase in prevalence and is emerging as one of the major health problems in society. However, until now, there are no first-line therapeutic agents for the allopathic treatment or reversal of the disease course. Therefore, the development of therapeutic modalities or drugs that are effective, easy to use, and suitable for long-term administration is important for the treatment of CI such as AD. Essential oils (EOs) extracted from natural herbs have a wide range of pharmacological components, low toxicity, and wide sources, In this review, we list the history of using volatile oils against cognitive disorders in several countries, summarize EOs and monomeric components with cognitive improvement effects, and find that they mainly act by attenuating the neurotoxicity of amyloid beta, anti-oxidative stress, modulating the central cholinergic system, and improving microglia-mediated neuroinflammation. And combined with aromatherapy, the unique advantages and potential of natural EOs in the treatment of AD and other disorders were discussed. This review hopes to provide scientific basis and new ideas for the development and application of natural medicine EOs in the treatment of CI.

Therapeutic Potential of Active Components from Acorus gramineus and Acorus tatarinowii in Neurological Disorders and Their Application in Korean Medicine

Neurological disorders represent a substantial healthcare burden worldwide due to population aging. Acorus gramineus Solander (AG) and Acorus tatarinowii Schott (AT), whose major component is asarone, have been shown to be effective in neurological disorders. This review summarized current information from preclinical and clinical studies regarding the effects of extracts and active components of AG and AT (e.g., α-asarone and β-asarone) on neurological disorders and biomedical targets, as well as the mechanisms involved. Databases, including PubMed, Embase, and RISS, were searched using the following keywords: asarone, AG, AT, and neurological disorders, including Alzheimer's disease, Parkinson's disease, depression and anxiety, epilepsy, and stroke. Meta-analyses and reviews were excluded. A total of 873 studies were collected. A total of 89 studies were selected after eliminating studies that did not meet the inclusion criteria. Research on neurological disorders widely reported that extracts or active components of AG and AT showed therapeutic efficacy in treating neurological disorders. These components also possessed a wide array of neuroprotective effects, including reduction of pathogenic protein aggregates, antiapoptotic activity, modulation of autophagy, anti-inflammatory and antioxidant activities, regulation of neurotransmitters, activation of neurogenesis, and stimulation of neurotrophic factors. Most of the included studies were preclinical studies that used in vitro and in vivo models, and only a few clinical studies have been performed. Therefore, this review summarizes the current knowledge on AG and AT therapeutic effects as a basis for further clinical studies, and clinical trials are required before these findings can be applied to human neurological disorders.

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.

Molecular Mechanisms and Therapeutic Potential of α- and β-Asarone in the Treatment of Neurological Disorders

Neurological disorders are important causes of morbidity and mortality around the world. The increasing prevalence of neurological disorders, associated with an aging population, has intensified the societal burden associated with these diseases, for which no effective treatment strategies currently exist. Therefore, the identification and development of novel therapeutic approaches, able to halt or reverse neuronal loss by targeting the underlying causal factors that lead to neurodegeneration and neuronal cell death, are urgently necessary. Plants and other natural products have been explored as sources of safe, naturally occurring secondary metabolites with potential neuroprotective properties. The secondary metabolites α- and β-asarone can be found in high levels in the rhizomes of the medicinal plant Acorus calamus (L.). α- and β-asarone exhibit multiple pharmacological properties including antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. This paper aims to provide an overview of the current research on the therapeutic potential of α- and β-asarone in the treatment of neurological disorders, particularly neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), as well as cerebral ischemic disease, and epilepsy. Current research indicates that α- and β-asarone exert neuroprotective effects by mitigating oxidative stress, abnormal protein accumulation, neuroinflammation, neurotrophic factor deficit, and promoting neuronal cell survival, as well as activating various neuroprotective signalling pathways. Although the beneficial effects exerted by α- and β-asarone have been demonstrated through in vitro and in vivo animal studies, additional research is required to translate laboratory results into safe and effective therapies for patients with AD, PD, and other neurological and neurodegenerative diseases.

The interplay between oxidative stress and autophagy: focus on the development of neurological diseases

Regarding the epidemiological studies, neurological dysfunctions caused by cerebral ischemia or neurodegenerative diseases (NDDs) have been considered a pointed matter. Mount-up shreds of evidence support that both autophagy and reactive oxygen species (ROS) are involved in the commencement and progression of neurological diseases. Remarkably, oxidative stress prompted by an increase of ROS threatens cerebral integrity and improves the severity of other pathogenic agents such as mitochondrial damage in neuronal disturbances. Autophagy is anticipated as a cellular defending mode to combat cytotoxic substances and damage. The recent document proposes that the interrelation of autophagy and ROS creates a crucial function in controlling neuronal homeostasis. This review aims to overview the cross-talk among autophagy and oxidative stress and its molecular mechanisms in various neurological diseases to prepare new perceptions into a new treatment for neurological disorders. Furthermore, natural/synthetic agents entailed in modulation/regulation of this ambitious cross-talk are described.

Shenzhiling oral liquid protects the myelin sheath against Alzheimer's disease through the PI3K/Akt-mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Shenzhiling oral liquid (SZL), a traditional Chinese medicine (TCM) compound, is firstly approved by the Chinese Food and Drug Administration (CFDA) for the treatment of mild to moderate Alzheimer's disease (AD). SZL is composed of ten Chinese herbs, and the precise therapy mechanism of its action to AD is far from fully understood.

AIM OF THE STUDY

The purpose of this study was to observe whether SZL is an effective therapy for amyloid-beta (Aβ)-induced myelin sheath and oligodendrocytes impairments. Notably, the primary aim was to elucidate whether and through what underlying mechanism SZL protects the myelin sheath through the PI3K/Akt-mTOR signaling pathway in Aβ₄₂-induced OLN-93 oligodendrocytes in vitro.

MATERIALS AND METHODS

APP/PS1 mice were treated with SZL or donepezil continuously for three months, and Aβ₄₂-induced oligodendrocyte OLN-93 cells mimicking AD pathogenesis of myelin sheath impairments were incubated with SZL-containing serum or with donepezil. LC-MS/MS was used to analysis the active components of SZL and SZL-containing serum. The Y maze test was administered after 3 months of treatment, and the hippocampal tissues of the APP/PS1 mice were then harvested for observation of myelin sheath and oligodendrocyte morphology. Cell viability and toxicity were assessed using CCK-8 and lactate dehydrogenase (LDH) release assays, and flow cytometry was used to measure cell apoptosis. The expression of the myelin proteins MBP, PLP, and MAG and that of Aβ₄₂ and Aβ₄₀ in the hippocampi of APP/PS1 mice were examined after SZL treatment. Simultaneously, the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR were also examined. The expression of proteins, including CNPase, Olig2, NKX2.2, MBP, PLP, MAG, MOG, p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, was determined by immunofluorescence and Western blot, and the corresponding gene expression was evaluated by qPCR in Aβ₄₂-induced OLN-93 oligodendrocytes.

RESULTS

LC-MS/MS detected a total of 126 active compounds in SZL-containing serum, including terpenoids, flavones, phenols, phenylpropanoids and phenolic acids. SZL treatment significantly improved memory and cognition in APP/PS1 mice and decreased the G-ratio of myelin sheath, alleviated myelin sheath and oligodendrocyte impairments by decreasing Aβ₄₂ and Aβ₄₀ accumulation and increasing the expression of myelin proteins MBP, PLP, MAG, and PI3K/Akt-mTOR signaling pathway associated protein in the hippocampi of APP/PS1 mice. SZL-containing serum also significantly reversed the OLN-93 cell injury induced by Aβ₄₂ by increasing cell viability and enhanced the expression of MBP, PLP, MAG, and MOG. Meanwhile, SZL-containing serum facilitated the maturation and differentiation of oligodendrocytes in Aβ₄₂-induced OLN-93 cells by heightening the expression of CNPase, Olig2 and NKX2.2. SZL-containing serum treatment also fostered the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, indicating an activating PI3K/Akt-mTOR signaling pathway in OLN-93 cells. Furthermore, the effects of SZL on myelin proteins, p-Akt, and p-mTOR were clearly inhibited by LY294002 and/or rapamycin, antagonists of PI3K and m-TOR, respectively.

CONCLUSIONS

Our findings indicate that SZL exhibits a neuroprotective effect on the myelin sheath by promoting the expression of myelin proteins during AD, and its mechanism of action is closely related to the activation of the PI3K/Akt-mTOR signaling pathway.

Mammalian/mechanistic target of rapamycin (mTOR) complexes in neurodegeneration

Novel targets to arrest neurodegeneration in several dementing conditions involving misfolded protein accumulations may be found in the diverse signaling pathways of the Mammalian/mechanistic target of rapamycin (mTOR). As a nutrient sensor, mTOR has important homeostatic functions to regulate energy metabolism and support neuronal growth and plasticity. However, in Alzheimer's disease (AD), mTOR alternately plays important pathogenic roles by inhibiting both insulin signaling and autophagic removal of β-amyloid (Aβ) and phospho-tau (ptau) aggregates. It also plays a role in the cerebrovascular dysfunction of AD. mTOR is a serine/threonine kinase residing at the core in either of two multiprotein complexes termed mTORC1 and mTORC2. Recent data suggest that their balanced actions also have implications for Parkinson's disease (PD) and Huntington's disease (HD), Frontotemporal dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS). Beyond rapamycin; an mTOR inhibitor, there are rapalogs having greater tolerability and micro delivery modes, that hold promise in arresting these age dependent conditions.

Effects of β-Asarone on Ischemic Stroke in Middle Cerebral Artery Occlusion Rats by an Nrf2-Antioxidant Response Elements (ARE) Pathway-Dependent Mechanism

Background

This study assessed the effects and underlying molecular mechanisms of β-asarone on ischemic stroke model rats.

Material/Methods

Ischemic stroke was induced by middle cerebral artery occlusion (MCAO) in rats. Before and after modeling, cognitive function was evaluated via fear conditioning test and neurological deficit was determined via Longa and Bederson scores. Following treatment with β-asarone or nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor for 20 consecutive days, the cerebral infarction was detected via TTC staining and Cresyl Violet staining in brain tissues. TUNEL staining and western blot analysis for apoptosis-related proteins were performed to assess the apoptosis of neurons. Nrf2-antioxidant response elements (ARE) pathway-related proteins were examined by RT-qPCR or western blot.

Results

The cognitive and neurological function was defective in MCAO rats. The infarction volumes and the apoptosis of cortical neurons were significantly increased in brain tissues of model rats, which were ameliorated after treatment with β-asarone. Meanwhile, the increase in pro-apoptotic proteins and decrease in anti-apoptotic proteins were found in brain tissues of model rats, which were markedly ameliorated by β-asarone treatment. However, Nrf2 inhibitor worsened the cerebral infarction and the apoptosis of neurons. Western blot results showed that β-asarone treatment activated the Nrf2-ARE pathway-related proteins in model rats, which was inhibited by Nrf2 inhibitor.

Conclusions

Our findings suggest that β-asarone treatment ameliorated the cerebral infarction in MCAO rats, which could be related to activation of the Nrf2-ARE pathway.

Potential benefits of phytochemicals from Azadirachta indica against neurological disorders

Azadirachta indica or Neem has been extensively used in the Indian traditional medical system because of its broad range of medicinal properties. Neem contains many chemically diverse and structurally complex phytochemicals such as limonoids, flavonoids, phenols, catechins, gallic acid, polyphenols, nimbins. These phytochemicals possess vast array of therapeutic activities that include anti-feedant, anti-viral, anti-malarial, anti-bacterial, anti-cancer properties. In recent years, many phytochemicals from Neem have been shown to be beneficial against various neurological disorders like Alzheimer's and Parkinson's disease, mood disorders, ischemic-reperfusion injury. The neuroprotective effects of the phytochemicals from Neem are primarily mediated by their anti-oxidant, anti-inflammatory and anti-apoptotic activities along with their ability to modulate signaling pathways. However, extensive studies are still required to fully understand the molecular mechanisms involved in neuropotective effects of phytochemicals from Neem. This review is an attempt to cover the neuroprotective properties of various phytochemicals from Neem along with their mechanism of action so that the potential of the compounds could be realized to reduce the burden of neurodegenerative diseases.

Mechanistic insights into the protective effects of chlorogenic acid against indomethacin-induced gastric ulcer in rats: Modulation of the cross talk between autophagy and apoptosis signaling

BACKGROUND

This study aimed to investigate the gastroprotective effect of chlorogenic acid (CGA) against Indomethacin (IND)-induced gastric ulcer (GU) in rats and its underlying mechanism, especially through autophagic and apoptotic pathways.

METHODS

Seventy-five rats were divided into five groups; control, IND (50 mg/kg, p.o.), CGA (100 mg/kg, p.o., 14 days), IND pretreated with CGA (50 mg/kg or 100 mg/kg, p.o., 14 days). The stomach tissues were examined to calculate the ulcer index and analyze markers of autophagy (beclin-1, LC3-II/LC3-I and p62), lysosomal function (cathepsin-D) and apoptosis (Bcl-2, Bax and caspase-3), along with expression of Akt/mTOR pathway using western blot or ELISA techniques. In addition, viability of gastric mucosal cells was detected by flowcytometry. Structural changes were assessed histologically, while autophagic and apoptotic changes of gastric mucosa were observed by transmission electron microscopy.

RESULTS

CGA exhibited a dose-dependent gastroprotective effect by reversing IND-induced accumulation of autophagic vacuoles, significant reduction in beclin-1, LC3-II/LC3-I, and p62 levels, and down-regulation of p-Akt/p-mTOR expression. CGA100 also restored normal autolysosomal function by modulation of cathepsin-D levels. Furthermore, pretreatment with CGA100 was significantly associated with an increase in antiapoptotic protein Bcl-2 along with a decrease in proapoptotic Bax and caspase-3 proteins in such a way that impairs IND-induced apoptosis. This was confirmed by CGA-induced significant decrease in annexin V⁺ cells.

CONCLUSIONS

The natural compound CGA offers a novel gastroprotective intervention against IND-induced GU through restoration of normal autophagic flux, impairment of apoptosis in a crosstalk mechanism mediated by Akt/mTOR pathway reactivation, and alleviation of IND-induced lysosomal dysfunction.

Traditional Chinese medicine compounds regulate autophagy for treating neurodegenerative disease: A mechanism review

Neurodegenerative diseases (NDs) are common chronic diseases related to progressive damage of the nervous system. Globally, the number of people with an ND is dramatically increasing consistent with the fast aging of society and one of the common features of NDs is the abnormal aggregation of diverse proteins. Autophagy is the main process by which misfolded proteins and damaged organelles are removed from cells. It has been found that the impairment of autophagy is associated with many NDs, suggesting that autophagy has a vital role in the neurodegeneration process. Recently, more and more studies have reported that autophagy inducers display a protective role in different ND experimental models, suggesting that enhancement of autophagy could be a potential therapy for NDs. In this review, the evidence for beneficial effects of traditional Chinese medicine (TCM) regulate autophagy in the models of Alzheimer's disease (AD), Parkinson's disease (PD), and other NDs are presented and common autophagy-related mechanisms are identified. The results demonstrate that TCM which regulate autophagy are potential therapeutic candidates for ND treatment.

β-Asarone improves learning and memory in Aβ1-42-induced Alzheimer's disease rats by regulating PINK1-Parkin-mediated mitophagy

Alzheimer's disease (AD) is a chronic neurodegenerative disease that is characterized by the extracellular accumulation of β-amyloid (Aβ). Many studies have shown a close relationship between autophagy and the formation of Aβ. As AD develops and progresses, mitophagy diminishes insoluble Aβ, and mitochondrial dysfunction seems to be a determining factor in the pathogenesis of AD. In our previous study, we showed that β-asarone pharmacological effects in APP/PS1 transgenic mice, reducing Aβ expression. However, the specific mechanism of this effect remains unclear. In this study, AD model rats induced by intracerebroventricular injection of Aβ_1-42 were randomly divided into nine groups, and medical intervention was applied to the animals for 30 days. Subsequently, spatial learning and memory were evaluated by the water maze test. Bcl-2 levels in the hippocampus were determined by western blotting (WB). The protein expression of Aβ_1-42, Beclin-1, p62, PINK1, and Parkin was assessed by WB and immunohistochemistry (IHC). The data showed that after β-asarone treatment, the learning and memory of the AD rats were clearly improved compared with those of the model group. Moreover, β-asarone decreased Aβ_1-42, Bcl-2, and p62 levels but increased Beclin-1 levels compared with those in the model group. In addition, we treated a group of rats with CsA to inhibit mitophagy. β-Asarone increased PINK1 and Parkin expression compared with that in the model group. The results showed that β-asarone can improve the learning and memory of rats with Aβ_1-42-induced AD by effectively promoting PINK1-Parkin-mediated mitophagy. Taken together, these results suggest that β-asarone may have the capacity to become a pharmaceutical agent for the treatment of AD in the future.

Recent Advances in Characterizing Natural Products that Regulate Autophagy

Autophagy, an intricate response to nutrient deprivation, pathogen infection, Endoplasmic Reticulum (ER)-stress and drugs, is crucial for the homeostatic maintenance in living cells. This highly regulated, multistep process has been involved in several diseases including cardiovascular and neurodegenerative diseases, especially in cancer. It can function as either a promoter or a suppressor in cancer, which underlines the potential utility as a therapeutic target. In recent years, increasing evidence has suggested that many natural products could modulate autophagy through diverse signaling pathways, either inducing or inhibiting. In this review, we briefly introduce autophagy and systematically describe several classes of natural products that implicated autophagy modulation. These compounds are of great interest for their potential activity against many types of cancer, such as ovarian, breast, cervical, pancreatic, and so on, hoping to provide valuable information for the development of cancer treatments based on autophagy.

Traditional Chinese Medicine: Role in Reducing β-Amyloid, Apoptosis, Autophagy, Neuroinflammation, Oxidative Stress, and Mitochondrial Dysfunction of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The major characteristics of AD are amyloid β plaques, apoptosis, autophagy dysfunction, neuroinflammation, oxidative stress, and mitochondrial dysfunction. These are mostly used as the significant indicators for selecting the effects of potential drugs. It is imperative to explain AD pathogenesis and realize productive treatments. Although the currently used chemical drugs for clinical applications of AD are effective in managing the symptoms, they are inadequate to achieve anticipated preventive or therapeutic outcomes. There are new strategies for treating AD. Traditional Chinese Medicine (TCM) has accumulated thousands of years of experience in treating dementia. Nowadays, numerous modern pharmacological studies have verified the efficacy of many bioactive ingredients isolated from TCM for AD treatment. In this review, representative TCM for the treatment of AD are discussed, and among these herbal medicines, the Lamiaceae family accounts for the highest proportion. It is concluded that monomers and extracts from TCM have potential therapeutic effect for AD treatment.

Role of Vacha (Acorus calamus Linn.) in Neurological and Metabolic Disorders: Evidence from Ethnopharmacology, Phytochemistry, Pharmacology and Clinical Study

Vacha (Acorus calamus Linn. (Acoraceae)) is a traditional Indian medicinal herb, which is practiced to treat a wide range of health ailments, including neurological, gastrointestinal, respiratory, metabolic, kidney, and liver disorders. The purpose of this paper is to provide a comprehensive up-to-date report on its ethnomedicinal use, phytochemistry, and pharmacotherapeutic potential, while identifying potential areas for further research. To date, 145 constituents have been isolated from this herb and identified, including phenylpropanoids, sesquiterpenoids, and monoterpenes. Compelling evidence is suggestive of the biopotential of its various extracts and active constituents in several metabolic and neurological disorders, such as anticonvulsant, antidepressant, antihypertensive, anti-inflammatory, immunomodulatory, neuroprotective, cardioprotective, and anti-obesity effects. The present extensive literature survey is expected to provide insights into the involvement of several signaling pathways and oxidative mechanisms that can mitigate oxidative stress, and other indirect mechanisms modulated by active biomolecules of A. calamus to improve neurological and metabolic disorders.

Neuroprotection by Walnut-Derived Peptides through Autophagy Promotion via Akt/mTOR Signaling Pathway against Oxidative Stress in PC12 Cells

Natural-derived peptides are effective substances in attenuating oxidative stress. However, their specific mechanisms have not been fully elucidated, especially in peptide-mediated autophagy. In the present study, TWLPLPR, YVLLPSPK, and KVPPLLY, novel peptides from Juglans mandshurica Maxim, prevented reactive oxygen species (ROS) production, elevated glutathione peroxidase (GSH-Px) activity and adenosine 5'-triphosphate (ATP) levels, and ameliorated apoptosis in Aβ_25-35 (at a concentration of 50 μM for 24 h)-induced PC12 cells (P < 0.01). Both western blot and immunofluorescence analysis illustrated that the peptides regulated Akt/mTOR signaling through p-Akt (Ser473) and p-mTOR (S2481) and promoted autophagy by increasing the levels of LC3-II/LC3-I and Beclin-1 while lowering p62 expression (P < 0.01). The autophagy inhibitor (3-methyladenine, 3-MA) and inducer (rapamycin, RAPA) were combined used to confirm the contribution of peptide-regulated autophagy in antioxidative effects. Moreover, the peptides increased the levels of LAMP1, LAMP2, and Cathepsin D (P < 0.05) and promoted the fusion with lysosomes to form autolysosomes, accelerating ROS removal. These data suggested that walnut-derived peptides regulated oxidative stress by promoting autophagy in the Aβ_25-35-induced PC12 cells.

β‑asarone modulates Beclin‑1, LC3 and p62 expression to attenuate Aβ40 and Aβ42 levels in APP/PS1 transgenic mice with Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly population. Autophagy is a well-known regulator of neurodegenerative diseases and β-asarone has been discovered to have certain neuropharmacological effects. Thus, the present study aimed to analyze the potential effects of β-asarone in AD and its possible mechanism of action in relation to autophagy. The present study investigated the effects of β-asarone on the number of senile plaques and amyloid β(Aβ)₄₀, Aβ₄₂, amyloid precursor protein (APP) and Beclin-1 mRNA levels in the hippocampus of APP/presenilin-1 (PS1) transgenic mice. The possible mechanism of β-asarone on autophagy-related proteins, including Beclin-1, light chain (LC)3A, LC3B and p62 levels, and the number of autophagosomes was also investigated. Mice were divided into a normal control group, a model group, a β-asarone-treated group, a 3-MA-treated group and a rapamycin-treated group. Treatments were continuously administered to all mice for 30 days by intragastric administration. The mice, including those in the normal and model control groups, were given equal volumes of saline. It was demonstrated that β-asarone treatment reduced the number of senile plaques and autophagosomes, and decreased Aβ₄₀, Aβ₄₂, APP and Beclin-1 expression in the hippocampus of model mice compared with untreated model mice. β-asarone also inhibited LC3A/B expression levels, but increased p62 expression. It was deduced that the neuroprotective effects of β-asarone in APP/PS1 transgenic mice resulted from its inhibition of autophagy. In conclusion, the data suggested that β-asarone should be explored further as a potential therapeutic agent in AD.

Schizandrol A protects against Aβ1-42-induced autophagy via activation of PI3K/AKT/mTOR pathway in SH-SY5Y cells and primary hippocampal neurons

Autophagy, a lysosomal degradative pathway, is crucial for the pathogenesis of Alzheimer's disease (AD). Schizandrol A (SchA) shows multiple pharmacological effects. However, the potential effects and mechanisms of SchA on amyloid-β (Aβ)-induced autophagy remain unclear. In this study, differentiated SH-SY5Y cells or primary hippocampal neurons were pretreated with SchA (2 μg/ml) for 1 h before subjected to Aβ_1-42 (10 μM) for 24 h to test its effects on cell viability, apoptosis, oxidative stress, and autophagy. Then an mTOR inhibitor (rapamycin) and a PI3K inhibitor (LY294002) were employed to explore the role of PI3K/AKT/mTOR pathway. The results showed that SchA significantly inhibited Aβ_1-42-triggered reduction of viable cells, increases of apoptotic cell number and pro-apoptotic protein expressions, as well as alterations of oxidative stress markers. In addition, the increases of LC3-II/LC3-I and Beclin-1 and decrease of p62 were suppressed by SchA. At the molecular level, we found that the inactivation of PI3K/AKT/mTOR pathway was ameliorated by SchA. Inhibition of PI3K/AKT/mTOR pathway deteriorated the protective effects of SchA against Aβ_1-42-induced autophagy activation, cell death, and apoptosis. In conclusion, we demonstrate that SchA attenuates Aβ_1-42-induced autophagy through activating PI3K/AKT/mTOR signaling pathway. SchA may be a novel drug for the prevention and treatment of AD.

Eicosapentaenoic Acid-Enriched Phosphatidylcholine Mitigated Aβ1-42-Induced Neurotoxicity via Autophagy-Inflammasome Pathway

Recent studies indicated that neuroinflammation contributes to the exacerbation of Alzheimer's disease (AD) and plays an important role in AD. The NOD-like receptor protein 3 (NLRP3) inflammasome, which is an important component of innate immune system, is associated with a wide range of human central nervous system disorders, including AD. Most of the studies focus on the protective effects of docosahexaenoic acid (DHA) in AD, but eicosapentaenoic acid (EPA) has rarely been involved. Here, we investigate the effects of EPA in the forms of phosphatidylcholine (EPA-PC) and ethyl esters (EPA-EE) in improving Aβ1-42-induced neurotoxicity. The spatial memory ability and the biochemical changes in the hippocampus were measured, including glial cell activation, tumor necrosis factor α production, NLRP3 inflammasome activation, and autophagic flux. The present results showed that the AD rats were significantly protected from spatial memory loss by the supplementation (EPA + DHA = 60 mg/kg, i.g., 20 days) of EPA-PC, while EPA-EE showed no significant benefit. Further mechanism studies suggested that EPA-PC could inhibit Aβ-induced neurotoxicity by alleviating NLRP3 inflammasome activation and enhancing autophagy. These findings indicate that EPA could improve cognitive deficiency in Aβ1-42-induced AD rats via autophagic inflammasomal pathway and the bioactivity differs in its molecular form.

Chlorogenic acid protects PC12 cells against corticosterone-induced neurotoxicity related to inhibition of autophagy and apoptosis

BACKGROUND

There are evidences that chlorogenic acid (CGA) has antidepressant effects, however the underlying molecular mechanism has not been well understood. The aim of the study was to explore the neuroprotective effect of CGA on corticosterone (CORT)-induced PC 12 cells and its mechanism, especially the autophagy pathway.

METHODS

PC12 cells were incubated with CORT (0, 100, 200, 400 or 800 μM) for 24 h, cell viability was measured by MTT assay. PC12 cells were cultured with 400 μM of CORT in the absence or presence of CGA (25 μg/ml) for 24 h, morphologies and specific marker of autophagosome were observed by transmission electron microscope (TEM) and confocal immunofluorescence microscopy, respectively. In addition, PC12 cells were treated with different doses of CGA (0, 6.25, 12.5, 25 or 50 μg/ml) with or without CORT (400 μM) for 24 h, cell viability and changes in the morphology were observed, and further analysis of apoptotic and autophagic proteins, and expression of AKT/mTOR signaling pathway were carried out by Western blot. Specific inhibitors of autophagy 3-Methyladenine (3-MA) and chloroquine (CQ) were added to the PC12 cells cultures to explore the potential role of autophagy in CORT-induced neuronal cell apoptosis.

RESULTS

Besides decreasing PC12 cell activity, CORT could also induce autophagy and apoptosis of PC12 cells, while CGA could reverse these effects. In addition, CGA treatment regulated AKT/mTOR signaling pathway in PC12 cells. CGA, similar to 3-MA and QC, significantly inhibited CORT-induced apoptosis in PC12 cells.

CONCLUSIONS

Our results provide a new molecular mechanism for the treatment of CORT-induced neurotoxicity by CGA, and suggest CGA may be a potential substance which is can alleviate depression.

Alcohol Dehydrogenase 1B Suppresses β-Amyloid-Induced Neuron Apoptosis

β-amyloid (Aβ) deposition, neurofibrillary tangles induced by phosphorylation of tau protein, and neuronal apoptosis are pathological hallmarks of Alzheimer’s disease (AD). The dementia rate in alcoholic abusers were found to be higher than in control people. The present study explored the potential roles of alcohol dehydrogenase 1B (ADH1B) in AD pathology by determining the ADH1B levels in AD patient sera, in the hippocampus of APP/PS-1 AD model mice, and in an AD model cell line treated with Aβ1-42. The results show that ADH1B levels decreased significantly both in the serum of AD patients and in the hippocampus of APP/PS-1 AD model mice. In addition, the apoptotic rate was reduced and viability was significantly increased in AD model cells transfected with ADH1B overexpression vector. The levels of the p75 neurotrophin receptor (p75NTR), an Aβ1-42 receptor, were down-regulated in the ADH1B overexpressing AD model cell and up-regulated in cells transfected with the shRNA vector of ADH1B. Protein levels of cleaved caspase-3 and Bax decreased significantly, whereas Bcl-2 levels increased in cells overexpressing ADH1B. The opposite trend was observed for cleaved caspase-3, Bax, and Bcl-2 levels in cells transfected with the shRNA vector of ADH1B. The levels of reactive oxygen species (ROS) were found to be reduced in ADH1B overexpressing cells and increased when cells were transfected with the shRNA vector of ADH1B. These results indicate that ADH1B might be important in the prevention of AD, especially for abusers of alcohol, and a potential new target of AD treatment.

1H Quantitative NMR analyses of β-asarone and related compounds for quality control of Acorus rhizome herbal drugs in terms of the effects of their constituents on in vitro acetylcholine esterase activity

We used quantitative nuclear magnetic resonance analyses to measure the contents of major constituents of Acorus rhizome materials used as herbal drugs. The inhibitory effects of crude n-hexane extracts and their individual constituents on in vitro acetylcholine esterase activity were evaluated. The crude extracts had unexpectedly weak inhibitory effects (46–64% inhibition at 1.0 mg/mL), despite the high content (46–64%) of β-asarone, which independently had a potent effect (IC50 2.9 µM [0.61 µg/mL]). Further investigation revealed participation of eudesmin A, a lignan constituent, in the suppression of the inhibitory effect of β-asarone.

Chinese Herbal Medicine for Mild Cognitive Impairment Using Montreal Cognitive Assessment: A Systematic Review

Background: Mild cognitive impairment (MCI) prevalence is estimated at 6%-12% of the population. It is possible that early treatment at the MCI stage could reduce progression to more severe cognitive impairment. The Montreal Cognitive Assessment (MoCA) is a sensitive measure used to assess changes in cognitive function. Various Chinese herbal medicines (CHMs) have been tested for effects on MCI using MoCA. Objectives: To evaluate the clinical evidence for CHMs on MoCA scores in MCI. Design: Five biomedical databases in English and Chinese language were searched for randomized controlled trials that compared orally administered CHMs with a control group and assessed changes in cognition using MoCA. Analyses were based on the comparison, control intervention, and study duration. Mean differences and 95% confidence intervals were calculated to evaluate treatment effects. For each study, risk of bias was assessed according to the Cochrane tool. Results: Nineteen studies were included with 16 contributing to the data analyses. Three studies were placebo controlled. Nine compared a CHM with a pharmacotherapy, three combined a CHM with a pharmacotherapy, and one combined CHM with cognitive training. In the two placebo-controlled studies of 24-week duration, results favored the CHMs at end of treatment. Conclusions: The systematic review suggests that the oral application of certain CHMs improved scores on MoCA by 1.76-2.34 points compared with placebo in people with MCI after 24 weeks of treatment. However, these two studies used different CHM formulations. Two studies that tested the same CHM formulation, Bu Yang Huan Wu Tang, in combination with donepezil, reported improvement in the integrative groups, but the studies were not blind and the durations were only 8-12 weeks. Overall, methodological weaknesses limited the strength of the evidence. The herbal formulae included ingredients that have received considerable research attention for their effects on memory and cognition. PROSPERO international prospective register of systematic reviews protocol registration number: CRD42018099650.

Heme and hemoglobin suppress amyloid β-mediated inflammatory activation of mouse astrocytes

Glial immune activity is a key feature of Alzheimer's disease (AD). Given that the blood factors heme and hemoglobin (Hb) are both elevated in AD tissues and have immunomodulatory roles, here we sought to interrogate their roles in modulating β-amyloid (Aβ)-mediated inflammatory activation of astrocytes. We discovered that heme and Hb suppress immune activity of primary mouse astrocytes by reducing expression of several proinflammatory cytokines (e.g. RANTES (regulated on activation normal T cell expressed and secreted)) and the scavenger receptor CD36 and reducing internalization of Aβ(1-42) by astrocytes. Moreover, we found that certain soluble (>75-kDa) Aβ(1-42) oligomers are primarily responsible for astrocyte activation and that heme or Hb association with these oligomers reverses inflammation. We further found that heme up-regulates phosphoprotein signaling in the phosphoinositide 3-kinase (PI3K)/Akt pathway, which regulates a number of immune functions, including cytokine expression and phagocytosis. The findings in this work suggest that dysregulation of Hb and heme levels in AD brains may contribute to impaired amyloid clearance and that targeting heme homeostasis may reduce amyloid pathogenesis. Altogether, we propose heme as a critical molecular link between amyloid pathology and AD risk factors, such as aging, brain injury, and stroke, which increase Hb and heme levels in the brain.

Therapeutic implication of autophagy in neurodegenerative diseases

Autophagy, a catabolic process necessary for the maintenance of intracellular homeostasis, has recently been the focus of numerous human diseases and conditions, such as aging, cancer, development, immunity, longevity, and neurodegeneration. However, the continued presence of autophagy is essential for cell survival and dysfunctional autophagy is thought to speed up the progression of neurodegeneration. The actual molecular mechanism behind the progression of dysfunctional autophagy is not yet fully understood. Emerging evidence suggests that basal autophagy is necessary for the removal of misfolded, aggregated proteins and damaged cellular organelles through lysosomal mediated degradation. Physiologically, neurodegenerative disorders are related to the accumulation of amyloid β peptide and α-synuclein protein aggregation, as seen in patients with Alzheimer’s disease and Parkinson’s disease, respectively. Even though autophagy could impact several facets of human biology and disease, it generally functions as a clearance for toxic proteins in the brain, which contributes novel insight into the pathophysiological understanding of neurodegenerative disorders. In particular, several studies demonstrate that natural compounds or small molecule autophagy enhancer stimuli are essential in the clearance of amyloid β and α-synuclein deposits. Therefore, this review briefly deliberates on the recent implications of autophagy in neurodegenerative disorder control, and emphasizes the opportunities and potential therapeutic application of applied autophagy.

Neuroprotective Effects and Mechanism of β-Asarone against Aβ1-42-Induced Injury in Astrocytes

Emerging evidence suggests that activated astrocytes play important roles in AD, and β-asarone, a major component of Acorus tatarinowii Schott, was shown to be a potential therapeutic candidate for AD. While our previous study found that β-asarone could improve the cognitive function of rats hippocampally injected with Aβ, the effects of β-asarone on astrocytes remain unclear, and this study aimed to investigate these effects. A rat model of Aβ1-42 (10 μg) was established, and the rats were intragastrically treated with β-asarone at doses of 10, 20, and 30 mg/kg or donepezil at a dose of 0.75 mg/kg. The sham and model groups were intragastrically injected with an equal volume of saline. Animals were sacrificed on the 28th day after administration of the drugs. In addition, a cellular model of Aβ1-42 (1.1 μM, 6 h) was established, and cells were treated with β-asarone at doses of 0, 2.06, 6.17, 18.5, 55.6, and 166.7 μg/mL. β-Asarone improved cognitive impairment, alleviated Aβ deposition and hippocampal damage, and inhibited GFAP, AQP4, IL-1β, and TNF-α expression. These results suggested that β-asarone could alleviate the symptoms of AD by protecting astrocytes, possibly by inhibiting TNF-α and IL-1β secretion and then downregulating AQP4 expression.

Autophagic compound database: A resource connecting autophagy-modulating compounds, their potential targets and relevant diseases

OBJECTIVES

Autophagy, a highly conserved lysosomal degradation process in eukaryotic cells, can digest long-lived proteins and damaged organelles through vesicular trafficking pathways. Nowadays, mechanisms of autophagy have been gradually elucidated and thus the discovery of small-molecule drugs targeting autophagy has always been drawing much attention. So far, some autophagy-related web servers have been available online to facilitate scientists to obtain the information relevant to autophagy conveniently, such as HADb, CTLPScanner, iLIR server and ncRDeathDB. However, to the best of our knowledge, there is not any web server available about the autophagy-modulating compounds.

METHODS

According to published articles, all the compounds and their relations with autophagy were anatomized. Subsequently, an online Autophagic Compound Database (ACDB) (http://www.acdbliulab.com/) was constructed, which contained information of 357 compounds with 164 corresponding signalling pathways and potential targets in different diseases.

RESULTS

We achieved a great deal of information of autophagy-modulating compounds, including compounds, targets/pathways and diseases. ACDB is a valuable resource for users to access to more than 300 curated small-molecule compounds correlated with autophagy.

CONCLUSIONS

Autophagic compound database will facilitate to the discovery of more novel therapeutic drugs in the near future.

β-asarone inhibited cell growth and promoted autophagy via P53/Bcl-2/Bclin-1 and P53/AMPK/mTOR pathways in Human Glioma U251 cells

Glioma is the most common type of primary brain tumor and has an undesirable prognosis. Autophagy plays an important role in cancer therapy, but it is effect is still not definite. P53 is an important tumor suppressor gene and protein that is closely to autophagy. Our aim was to study the effect of β-asarone on inhibiting cell proliferation in human glioma U251 cells and to detect the effect of the inhibition on autophagy through the P53 signal pathway. For cell growth, the cells were divided into four groups: the model, β-asarone, temozolomide (TMZ), and co-administration groups. For cell autoghapy and the P53 pathway, the cells were divided into six groups: the model, β-asarone, 3MA, Rapa, Pifithrin-µ, and NSC groups. The counting Kit-8 assay and flow cytometry (FCM) were then used to measure the cell proliferation and cycle. Electron microscopy was used to observe autophagosome formation. Cell immunohistochemistry/-immunofluorescence, FCM and Western blot (WB) were used to examine the expression of Beclin-1 and P53. The levels of P53 and GAPDH mRNA were detected by RT-PCR. Using WB, we determined autophagy-related proteins Beclin-1, LC3-II/I, and P62 and those of the P53 pathway-related proteins P53, Bcl-2, mTOR, P-mTOR, AMPK, P-AMPK, and GAPDH. We got the results that β-asarone changed the cellular morphology, inhibited cell proliferation, and enhanced the expression of P53, LC3-II/I, Beclin-1, AMPK, and pAMPK while inhibiting the expression of P62, Bcl-2, mTOR, and pmTOR. All the data suggested that β-asarone could reduce the cell proliferation and promote autophagy possible via the P53 pathway in U251 cells.

Arrestins contribute to amyloid beta-induced cell death via modulation of autophagy and the α7nAch receptor in SH-SY5Y cells

Amyloid β-protein (Aβ) is believed to contribute to the development of Alzheimer’s disease (AD). Here we showed that Aβ_25-35 rapidly caused activation of autophagy, subsequently leading to reduction of autophagy associated with cellular apoptosis. Further investigation revealed that the accumulation of β-arrestin 1 (ARRB1) caused by Aβ_25-35 contributed to the induction of autophagic flux. The depletion of ARRB1 led to decreases in the expression of LC3B, Atg7, and Beclin-1, which are essential for the initiation of autophagy. ARRB1 depletion also reduced downstream ERK activity and promoted Aβ_25-35-induced cell death. As with ARRB1, transient upregulation of ARRB2 by Aβ_25-35 was observed after short treatment durations, whereas genetic reduction of ARRB2 caused a marked increase in the expression of the α7nAch receptor at the cell surface, which resulted in partial reversal of Aβ_25-35-induced cell death. Although expression of both ARRB1 and ARRB2 was reduced in serum from patients with AD, the levels of ARRB1 were much lower than those of ARRB2 in AD. Thus, our findings indicate that ARRB1/2 play different roles in Aβ_25-35 cytotoxicity, which may provide additional support for exploring the underlying molecular mechanism of AD.

Berberine improves cognitive impairment by promoting autophagic clearance and inhibiting production of β-amyloid in APP/tau/PS1 mouse model of Alzheimer's disease

This study investigates the neuroprotective properties of berberine (a natural isoquinoline alkaloid isolated from the Rhizoma coptidis) and finds that berberine could promote β-amyloid (Aβ) clearance and inhibit Aβ production in the triple-transgenic mouse model of Alzheimer's disease (3×Tg-AD). During the study, berberine was first administrated to treat 3×Tg-AD mice and primary neurons. Morris water maze assay, western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining and histological analysis, transmission electron microscopic analysis were then used to evaluate the effects of the berberine administration. The result showed that berberine significantly improved 3×Tg-AD mice's spatial learning capacity and memory retention, promoted autophagy activity identified by the enhancement of brain LC3-II, beclin-1, hVps34, and Cathepsin-D levels as well as the reduction of brain P62 and Bcl-2 levels in AD mice, facilitated reduction of Aβ and APP levels, reduced Aβ plaque deposition in the hippocampus of AD mice, and inhibited b-site APP cleavage enzyme 1 (BACE1) expression. Similar results were also found in 3×Tg-AD primary hippocampal neurons: berbernine treatment decreased the levels of extracellular and intracellular Aβ1-42, increased the protein levels of LC3-II, beclin-1, hVps34, and Cathepsin-D, and decreased the levels of P62, Bcl-2, APP and BACE1 levels. In summary, berberine shows neuroprotective effects on 3×Tg-AD mice and may be a promising multitarget drug in the preventionand protection against AD.

Evaluating the Effectiveness of GTM-1, Rapamycin, and Carbamazepine on Autophagy and Alzheimer Disease

Background

This study was proposed to compare the efficacy and safety of GTM-1, Rapamycin (Rap), and Carbamazepine (CBZ) in managing Alzheimer disease (AD). The impact of the above mentioned therapeutic drugs on autophagy was also investigated in our study.

Material/Methods

Firstly, 3×Tg AD mice were randomly allocated into 4 groups (each group with 10 mice), in which AD mice were separately treated with dimethylsulfoxide (DMSO, vehicle group), GTM-1 (6 mg/kg), Rap (1 mg/kg), and CBZ (100 mg/kg). Then spatial memory and learning ability of mice was tested using the Morris water maze. Routine blood tests were performed to evaluate the toxicity of these drugs. Amyloid-β42 (Aβ42) concentration was detected by ELISA and immunohistochemistry. Proteins related to autophagy were detected by Western blot.

Results

GTM-1, Rap, and CBZ significantly improved the spatial memory of 3×Tg AD mice compared to that in the vehicle group (all P<0.05). Moreover, this study revealed that CBZ dosage was related to toxicity in mice. All of the above drugs significantly increased the expression of LC3-II and reduced Aβ42 levels in hippocampi of 3×Tg AD mice (all P<0.05). On the other hand, neither GTM-1 nor CBZ had significant influence on the expression of proteins on the mTOR pathway.

Conclusions

GTM-1 can alleviate the AD syndrome by activating autophagy in a manner that is dependent on the mTOR pathway and it therefore can be considered as an alternative to Rap.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Targeting molecules to medicine with mTOR, autophagy and neurodegenerative disorders

Neurodegenerative disorders are significantly increasing in incidence as the age of the global population continues to climb with improved life expectancy. At present, more than 30 million individuals throughout the world are impacted by acute and chronic neurodegenerative disorders with limited treatment strategies. The mechanistic target of rapamycin (mTOR), also known as the mammalian target of rapamycin, is a 289 kDa serine/threonine protein kinase that offers exciting possibilities for novel treatment strategies for a host of neurodegenerative diseases that include Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, stroke and trauma. mTOR governs the programmed cell death pathways of apoptosis and autophagy that can determine neuronal stem cell development, precursor cell differentiation, cell senescence, cell survival and ultimate cell fate. Coupled to the cellular biology of mTOR are a number of considerations for the development of novel treatments involving the fine control of mTOR signalling, tumourigenesis, complexity of the apoptosis and autophagy relationship, functional outcome in the nervous system, and the intimately linked pathways of growth factors, phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation two homologue one (Saccharomyces cerevisiae) (SIRT1) and others. Effective clinical translation of the cellular signalling mechanisms of mTOR offers provocative avenues for new drug development in the nervous system tempered only by the need to elucidate further the intricacies of the mTOR pathway.

β-asarone improves learning and memory and reduces Acetyl Cholinesterase and Beta-amyloid 42 levels in APP/PS1 transgenic mice by regulating Beclin-1-dependent autophagy

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly, and studies have suggested that β-asarone has pharmacological effects on beta-amyloid (Aβ) injected in the rat hippocampus. However, the effect of β-asarone on autophagy in the APP/PS1 transgenic mouse is unreported. APP/PS1 transgenic mice were randomly divided into six groups (n=10/group): an untreated group, an Aricept-treated group, a 3-MA-treated group, a rapamycin-treated group, an LY294002-treated group, a β-asarone-treated group. The control group consisted of wild-type C57BL/6 mice. All treatments were administered to the mice for 30 days. Spatial learning and memory were assessed by water maze, passive avoidance, and step-down tests. AChE and Aβ₄₂ levels in the hippocampus were determined by ELISA. p-Akt, p-mTOR, and LC3B expression were detected by flow cytometry. The expression of p-Akt, p-mTOR, Beclin-1, and p62 proteins was assessed by western blot. Changes in autophagy were viewed using a transmission electron microscope. APP and Beclin-1 mRNA levels were measured by Real-Time PCR. The learning and memory of APP/PS1 transgenic mice were improved significantly after β-asarone treatment compared with the untreated group. In addition, β-asarone treatment reduced AChE and Aβ₄₂ levels, increased p-mTOR and p62 expression, decreased p-Akt, Beclin-1, and LC3B expression, decreased the number of autophagosomes and reduced APP mRNA and Beclin-1 mRNA levels compared with the untreated group. That is, β-asarone treatment can improve the learning and memory abilities of APP/PS1 transgenic mouse by inhibiting Beclin-1-dependent autophagy via the PI3K/Akt/mTOR pathway.

Beta-asarone protects against MPTP-induced Parkinson's disease via regulating long non-coding RNA MALAT1 and inhibiting α-synuclein protein expression

OBJECTIVE

Numerous long non-coding RNAs (lncRNA) have been identified in neurodegenerative disorders including Parkinson's disease (PD). Emerging evidence demonstrates that β-asarone functions as neuroprotective effects in both in vitro and in vivo models. However, the role of β-asarone and its potential mechanism in PD remain not completely clear.

METHODS

MPTP-induced PD mouse model and SH-SY5Y cells subjected to MPP+ as its in vitro model were used to evaluate the effects of β-asarone on PD. LncRNA MALAT1 and α-synuclein expression were determined by real-time PCR and western blot methods.

RESULTS

β-Asarone significantly increased the TH+ cells number and decreased the expression levels of MALAT1 and α-synuclein in midbrain tissue of PD mice. RNA pull-down and immunoprecipitation assays confirmed that MALAT1 associated with α-synuclein, leading to the increased stability of α-synuclein and its expression in SH-SY5Y cells. β-asarone elevated the viability of cells exposed to MPP+. Either overexpressed MALAT1 or α-synuclein could canceled the protective effect of β-asarone on cell viability. In PD mice, pcDNA-MALAT1 also decreased the TH+ cells number and increased the α-synuclein expression in PD mice with treatment of β-asarone.

CONCLUSION

β-Asarone functions as a neuroprotective effect in both in vivo and in vitro models of PD via regulating MALAT1 and α-synuclein expression.

Neuroprotective effect of β-asarone against Alzheimer's disease: regulation of synaptic plasticity by increased expression of SYP and GluR1

Aim

β-asarone, an active component of Acori graminei rhizome, has been reported to have neuroprotective effects in Alzheimer’s disease. As the underlying mechanism is not known, we investigated the neuroprotective effects of β-asarone in an APP/PS1 double transgenic mouse model and in NG108 cells.

Materials and methods

APPswe/PS1dE9 double transgenic male mice were randomly assigned to a model group, β-asarone treatment groups (21.2, 42.4, or 84.8 mg/kg/d), or donepezil treatment group (2 mg/kg/d). Donepezil treatment was a positive control, and background- and age-matched wild-type B6 mice were an external control group. β-asarone (95.6% purity) was dissolved in 0.8% Tween 80 and administered by gavage once daily for 2.5 months. Control and model animals received an equal volume of vehicle. After 2.5 months of treatment, behavior of all animals was evaluated in a Morris water maze. Expression of synaptophysin (SYP) and glutamatergic receptor 1 (G1uR1) in the hippocampus and cortex of the double transgenic mice was assayed by Western blotting. The antagonistic effects of β-asarone against amyloid-β peptide (Aβ) were investigated in vitro in the NG108-15 cell line. After 24 hours of incubation, cells were treated with 10 μm Aβ with or without β-asarone at different concentrations (6.25, 12.5, or 25 μM) for an additional 36 hours. The cytotoxicity of β-asarone was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay of cell viability, and cell morphology was evaluated by bright-field microscopy after 24 hours of treatment. The expression of SYP and GluR1 in cells was detected by Western blot assay in the hippocampus and brain cortex tissues of mice.

Results

β-asarone at a high dose reduced escape latency and upregulated SYP and GluR1 expression at both medium and high doses. Cell morphology evaluation showed that β-asarone treatment did not result in obvious cell surface spots and cytoplasmic granularity. β-asarone had a dose-dependent effect on cell proliferation.

Conclusion

β-asarone antagonized the Aβ neurotoxicity in vivo, improved the learning and memory ability of APP/PS1 mice, and increased the expression of SYP and GluR1 both in vivo and in vitro. Thus, β-asarone may be a potential drug for the treatment of Alzheimer’s disease.

Electroacupuncture improves memory and protects neurons by regulation of the autophagy pathway in a rat model of Alzheimer's disease

BACKGROUND

Acupuncture is a potential therapy for Alzheimer's disease (AD), but its clinical effects and underlying mechanisms are not fully understood. Emerging evidence suggests autophagy is involved in β-amyloid (Aβ) clearance. We hypothesised that electroacupuncture (EA) treatment of AD involves the autophagy pathway in rats.

METHODS

We injected 2μl Aβ_1-40 bilaterally into the hippocampi of 42 rats to establish AD. Rats remained untreated (AD group, n=14) or received 24 EA treatments at GV20+BL23 over 28 days from day 7 post-injection with/without co-treatment with 3-methyladenine (3-MA), an autophagy inhibitor (AD+EA+3-MA and AD+EA groups, respectively, n=14 each). Cognitive function was evaluated by Morris water maze (MWM) testing. Hippocampi were examined by transmission electron microscopy (TEM) and stained with haematoxylin and eosin/transferase dUTP nick end labelling (TUNEL) to assess neuronal morphology/apoptosis, respectively. Protein expression of Beclin-1, LC3 and Aβ_1-40 was examined.

RESULTS

In the MWM test, the AD+EA group showed an improvement in parameters consistent with improved learning/memory compared to untreated AD rats, and 3-MA attenuated these effects. EA mitigated cellular apoptosis resulting from Aβ infusion in the CA1 region and enhanced LC3II/LC3I ratios and Beclin-1 expression. Numerous autophagosome precursors and enlarged autophagosomes were observed by TEM in the hippocampi of EA-treated rats. Reduced Aβ levels, and co-localisation of Aβ and LC3II, were observed following EA treatment by immunofluorescence staining. EA+3-MA treated rats had much higher TUNEL-positive neurons, lower LC3II/LC3I ratios and Beclin-1 expression, and elevated Aβ levels compared with EA alone.

CONCLUSIONS

EA reduces neuronal apoptosis, enhances degradation of Aβ, and improves learning/memory in AD rats by upregulating the autophagy pathway.