Aromatic-Turmerone Attenuates LPS-Induced Neuroinflammation and Consequent Memory Impairment by Targeting TLR4-Dependent Signaling Pathway

Unlocking the medicinal arsenal of Cissus assamica: GC-MS/MS, FTIR, and molecular docking insights

Background and aims

This study investigated the biochemical components present in the leaves of Cissus assamica. The primary aim was to analyze these components using advanced techniques and assess their potential therapeutic applications.

Methodology

Fourier Transform Infrared (FT-IR) spectroscopy, Gas Chromatography-Mass Spectrometry (GC-MS), and Mass Spectral analysis were employed to identify and characterize the compounds in Cissus assamica leaves. The mass spectra of each compound were compared with data from the Wiley and NIST libraries to determine their names, molecular masses, and chemical structures. FT-IR analysis identified characteristic functional groups by their specific frequencies.

Results and discussion

FT-IR spectroscopic analysis revealed significant molecular vibrations at frequencies of 3265.63, 2853.81, 1638.60, 1469.21, and 1384.95 cm⁻¹, indicating the presence of specific functional groups. The GC-MS analysis identified distinct compounds, such as "aR-Turmerone," "Curlone," "7,8-Epoxylanostan-11-ol, 3-acetoxy-," "13-Docosenamide, (Z)-," "Phenol, 3,5-bis(1,1-dimethylethyl)-," "9,19-Cyclolanostan-3-ol, 24,24-epoxymethano-, acetate," and "Quinoline-5,8-dione-6-ol, 7-[[(4-cyclohexylbutyl)amino]methyl]-." These compounds exhibited potential therapeutic applications. Their cytotoxic, antimicrobial, antidiarrheal, anti-hyperglycemic, and pain-relieving properties were evaluated by comparing them with reference ligands targeting specific receptors, including dihydrofolate reductase (DHFR), epidermal growth factor receptor (EGFR), kappa opioid receptor (KOR), glucose transporter 3 (GLUT 3), and cyclooxygenase 2 (COX-2).

Conclusion

The results of this study suggest that Cissus assamica leaves contain bioactive compounds with potential therapeutic benefits for treating infections, diarrhea, hyperglycemia, and pain. However, further research is needed to conduct comprehensive phytochemical screening and establish the precise mechanisms of action for the crude extract or the plant-derived compounds.

Identification of a novel aromatic-turmerone analog that activates chaperone-mediated autophagy through the persistent activation of p38

Introduction: Aromatic (Ar)-turmerone is a bioactive component of turmeric oil obtained from Curcuma longa. We recently identified a novel analog (A2) of ar-turmerone that protects dopaminergic neurons from toxic stimuli by activating nuclear factor erythroid 2-related factor 2 (Nrf2). D-cysteine increases Nrf2, leading to the activation of chaperone-mediated autophagy (CMA), a pathway in the autophagy-lysosome protein degradation system, in primary cultured cerebellar Purkinje cells. In this study, we attempted to identify novel analogs of ar-turmerone that activate Nrf2 more potently and investigated whether these analogs activate CMA. Methods: Four novel analogs (A4-A7) from A2 were synthesized. We investigated the effects of A2 and novel 4 analogs on Nrf2 expression via immunoblotting and CMA activity via fluorescence observation. Results: Although all analogs, including A2, increased Nrf2 expression, only A4 activated CMA in SH-SY5Y cells. Additionally, A4-mediated CMA activation was not reversed by Nrf2 inhibition, indicating that A4 activated CMA via mechanisms other than Nrf2 activation. We focused on p38, which participates in CMA activation. Inhibition of p38 significantly prevented A4-mediated activation of CMA. Although all novel analogs significantly increased the phosphorylation of p38 6 h after drug treatment, only A4 significantly increased phosphorylation 24 h after treatment. Finally, we revealed that A4 protected SH-SY5Y cells from the cytotoxicity of rotenone, and that this protection was reversed by inhibiting p38. Conclusion: These findings suggest that the novel ar-turmerone analog, A4, activates CMA and protects SH-SY5Y cells through the persistent activation of p38.

Essential Oil Constituents as Anti-Inflammatory and Neuroprotective Agents: An Insight through Microglia Modulation

Microglia are key players in the brain's innate immune response, contributing to homeostatic and reparative functions but also to inflammatory and underlying mechanisms of neurodegeneration. Targeting microglia and modulating their function may have therapeutic potential for mitigating neuroinflammation and neurodegeneration. The anti-inflammatory properties of essential oils suggest that some of their components may be useful in regulating microglial function and microglial-associated neuroinflammation. This study, starting from the ethnopharmacological premises of the therapeutic benefits of aromatic plants, assessed the evidence for the essential oil modulation of microglia, investigating their potential pharmacological mechanisms. Current knowledge of the phytoconstituents, safety of essential oil components, and anti-inflammatory and potential neuroprotective effects were reviewed. This review encompasses essential oils of Thymus spp., Artemisia spp., Ziziphora clinopodioides, Valeriana jatamansi, Acorus spp., and others as well as some of their components including 1,8-cineole, β-caryophyllene, β-patchoulene, carvacrol, β-ionone, eugenol, geraniol, menthol, linalool, thymol, α-asarone, and α-thujone. Essential oils that target PPAR/PI3K-Akt/MAPK signalling pathways could supplement other approaches to modulate microglial-associated inflammation to treat neurodegenerative diseases, particularly in cases where reactive microglia play a part in the pathophysiological mechanisms underlying neurodegeneration.

Turmeric-Derived Nanoparticles Functionalized Aerogel Regulates Multicellular Networks to Promote Diabetic Wound Healing

Regulation of excessive inflammation and impaired cell proliferation is crucial for healing diabetic wounds. Although plant-to-mammalian regulation offers effective approaches for chronic wound management, the development of a potent plant-based therapeutic presents challenges. This study aims to validate the efficacy of turmeric-derived nanoparticles (TDNPs) loaded with natural bioactive compounds. TDNPs can alleviate oxidative stress, promote fibroblast proliferation and migration, and reprogram macrophage polarization. Restoration of the fibroblast-macrophage communication network by TDNPs stimulates cellular regeneration, in turn enhancing diabetic wound healing. To address diabetic wound management, TDNPs are loaded in an ultralight-weight, high swelling ratio, breathable aerogel (AG) constructed with cellulose nanofibers and sodium alginate backbones to obtain TDNPs@AG (TAG). TAG features wound shape-customized accessibility, water-adaptable tissue adhesiveness, and capacity for sustained release of TDNPs, exhibiting outstanding performance in facilitating in vivo diabetic wound healing. This study highlights the potential of TDNPs in regenerative medicine and their applicability as a promising solution for wound healing in clinical settings.

Integrating network pharmacology and experimental verification to decipher the multitarget pharmacological mechanism of Cinnamomum zeylanicum essential oil in treating inflammation

Inflammatory diseases contribute to more than 50 % of global deaths. Research suggests that network pharmacology can reveal the biological mechanisms underlying inflammatory diseases and drug effects at the molecular level. The aim of the study was to clarify the biological mechanism of Cinnamomum zeylanicum essential oil (CZEO) and predict molecular targets of CZEO against inflammation by employing network pharmacology and in vitro assays. First, the genes related to inflammation were identified from the Genecards and Online Mendelian Inheritance in Man (OMIM) databases. The CZEO targets were obtained from the SwissTargetPrediction and Similarity Ensemble Approach (SEA) database. A total of 1057 CZEO and 526 anti-inflammation targets were obtained. The core hub target of CZEO anti-inflammatory was obtained using the protein-protein interaction network. KEGG pathway analysis suggested CZEO to exert anti-inflammatory effect mainly through Tumor necrosis factor, Toll-like receptor and IL-17 signalling pathway. Molecular docking of active ingredients-core targets interactions was modelled using Pyrx software. Docking and simulation studies revealed benzyl benzoate to exhibit good binding affinity towards IL8 protein. MTT assay revealed CZEO to have non-cytotoxic effect on RAW 264.7 cells. CZEO also inhibited the production of NO, PGE2, IL-6, IL-1β and TNF-α and promoted the activity of endogenous antioxidant enzymes in LPS-stimulated RAW 264.7 cells. Additionally, CZEO inhibited intracellular ROS generation, NF-kB nuclear translocation and modulated the expression of downstream genes involved in Toll-like receptor signalling pathway. The results deciphered the mechanism of CZEO in treating inflammation and provided a theoretical basis for its clinical application.

TLR4/NFκB-Mediated Anti-Inflammatory and Antioxidative Effect of Hexanic and Ethanolic Extracts of Curcuma longa L. in Buffalo Mammary Epithelial Cells

Mastitis is the commonest disease of bovines imposing a great economic setback and a drastic public health concern worldwide. Antibiotic resistance is the preliminary con of excessive antibiotics use for disease treatment. Studies validate an alarming increase in the antibiotic resistance of both humans and animals. For ages, medicinal plants have been used to treat a number of ailments in humans and animals, including mastitis. Curcuma longa, or turmeric, is the prerequisite in Indian cooking and has been used in traditional medicine for its magical properties. The rhizome of C. longa possesses significant anti-inflammatory, antibacterial, antifungal, and antioxidative properties. In the current study, we evaluated the hexanic and ethanolic extracts of C. longa for their anti-inflammatory and antioxidative potential against LPS-induced inflammation in buffalo mammary epithelial cells (BuMECs). Pretreatment with the extracts downregulated the expression of proinflammatory cytokine TNFα via the TLR4/NFκB-mediated signaling pathway. However, IL-6 was downregulated in only the hexanic C. longa-pretreated group. A significant upregulation of NRF2 mRNA expression was seen in both hexanic- and ethanolic-treated groups. A GC-MS/MS study of the extracts revealed the presence of important sesqueterpenoids and phenolics as the main bioactive phytoconstituents in the extracts. Sesqueterpenoids, such as turmerone, ar-turmerone, curlone, and atlantone, and phenols, such as guaiacol (2-Hydroxyanisole phenol, 2-methoxy), and ethyl ferulate/ethyl 4′-hydroxy-3′methoxycinnamate, were found in C. longa extracts. The protective role of C. longa in BuMECs against LPS-induced inflammation and oxidant insult might be due to the presence of bioactive compounds, such as terpenoid and phenolic compounds. However, we further propose the isolation of these phytoconstituents and their analysis using HPLC and NMR studies.

Fatty Acid-Derived N-acylethanolamines Dietary Supplementation Attenuates Neuroinflammation and Cognitive Impairment in LPS Murine Model

Neuroinflammation plays a critical role in the pathogenesis of most neurological and neurodegenerative diseases and therefore represents a potential therapeutic target. In this regard, accelerating the resolution process in chronic neuroinflammation may be an effective strategy to deal with the cognitive consequences of neuropathology and generalized inflammatory processes. N-acylethanolamine (NAE) derivatives of fatty acids, being highly active lipid mediators, possess pro-resolving activity in inflammatory processes and are promising agents for the suppression of neuroinflammation and its consequences. This paper is devoted to a study of the effects played by dietary supplement (DS), containing a composition of fatty acid-derived NAEs, obtained from squid Berryteuthis magister, on the hippocampal neuroinflammatory and memory processes. By detecting the production of pro-inflammatory cytokines and glial markers, a pronounced anti-inflammatory activity of DS was demonstrated both in vitro and in vivo. DS administration reversed the LPS-induced reduction in hippocampal neurogenesis and memory deterioration. LC-MS analysis revealed an increase in the production of a range of NAEs with well-documented anti-inflammatory activity in response to the administered lipid composition. To conclude, we found that tested DS suppresses the neuroinflammatory response by reducing glial activation, positively regulates neural progenitor proliferation, and attenuates hippocampal-dependent memory impairment.

Preventive effects of arctigenin from Arctium lappa L against LPS-induced neuroinflammation and cognitive impairments in mice

Arctigenin (Arc) is a phenylpropanoid dibenzylbutyrolactone lignan in Arctium lappa L, which has been widely applied as a traditional Chinese herbal medicine for treating inflammation. In the present study, we explored the neuroprotective effect and the potential mechanisms of arctigenin against LPS-evoked neuroinflammation, neurodegeneration, and memory impairments in the mice hippocampus. Daily administration of arctigenin (50 mg/kg per day, i.g.) for 28 days revealed noticeable improvements in spatial learning and memory deficits after exposure to LPS treatment. Arctigenin prevented LPS-induced neuronal/synaptic injury and inhibited the increases in Abeta (Aβ) generation and the levels of amyloid precursor protein (APP) and β-site amyloid precursor protein cleavage enzyme 1 (BACE1). Moreover, arctigenin treatment also suppressed glial activation and reduced the production of proinflammatory cytokines. In LPS-treated BV-2 microglial cells and mice, activation of the TLR4 mediated NF-κB signaling pathway was significantly suppressed by arctigenin administration. Mechanistically, arctigenin reduced the LPS-induced interaction of adiponectin receptor 1 (AdipoR1) with TLR4 and its coreceptor CD14 and inhibited the TLR4-mediated downstream inflammatory response. The outcomes of the current study indicate that arctigenin mitigates LPS-induced apoptotic neurodegeneration, amyloidogenesis and neuroinflammation as well as cognitive impairments, and suggest that arctigenin may be a potential therapeutic candidate for neuroinflammation/neurodegeneration-related diseases.

Natural Products as Novel Neuroprotective Agents; Computational Predictions of the Molecular Targets, ADME Properties, and Safety Profile

Neurodegenerative diseases (NDs) are one of the most challenging public health issues. Despite tremendous advances in our understanding of NDs, little progress has been made in establishing effective treatments. Natural products may have enormous potential in preventing and treating NDs by targeting microglia; yet, there have been several clinical concerns about their usage, primarily due to a lack of scientific evidence for their efficacy, molecular targets, physicochemical properties, and safety. To solve this problem, the secondary bioactive metabolites derived from neuroprotective medicinal plants were identified and selected for computational predictions for anti-inflammatory activity, possible molecular targets, physicochemical properties, and safety evaluation using PASS online, Molinspiration, SwissADME, and ProTox-II, respectively. Most of the phytochemicals were active as anti-inflammatory agents as predicted using the PASS online webserver. Moreover, the molecular target predictions for some phytochemicals were similar to the reported experimental targets. Moreover, the phytochemicals that did not violate important physicochemical properties, including blood-brain barrier penetration, GI absorption, molecular weight, and lipophilicity, were selected for further safety evaluation. After screening 54 neuroprotective phytochemicals, our findings suggest that Aromatic-turmerone, Apocynin, and Matrine are the most promising compounds that could be considered when designing novel neuroprotective agents to treat neurodegenerative diseases via modulating microglial polarization.

Medicine-Food Herbs against Alzheimer’s Disease: A Review of Their Traditional Functional Features, Substance Basis, Clinical Practices and Mechanisms of Action

Alzheimer’s disease (AD) is a progressive, neurodegenerative disorder that currently has reached epidemic proportions among elderly populations around the world. In China, available traditional Chinese medicines (TCMs) that organically combine functional foods with medicinal values are named “Medicine Food Homology (MFH)”. In this review, we focused on MFH varieties for their traditional functional features, substance bases, clinical uses, and mechanisms of action (MOAs) for AD prevention and treatment. We consider the antiAD active constituents from MFH species, their effects on in vitro/in vivo AD models, and their drug targets and signal pathways by summing up the literature via a systematic electronic search (SciFinder, PubMed, and Web of Science). In this paper, several MFH plant sources are discussed in detail from in vitro/in vivo models and methods, to MOAs. We found that most of the MFH varieties exert neuroprotective effects and ameliorate cognitive impairments by inhibiting neuropathological signs (Aβ-induced toxicity, amyloid precursor protein, and phosphorylated Tau immunoreactivity), including anti-inflammation, antioxidative stress, antiautophagy, and antiapoptosis, etc. Indeed, some MFH substances and their related phytochemicals have a broad spectrum of activities, so they are superior to simple single-target drugs in treating chronic diseases. This review can provide significant guidance for people’s healthy lifestyles and drug development for AD prevention and treatment.

Parasite-Derived Excretory-Secretory Products Alleviate Gut Microbiota Dysbiosis and Improve Cognitive Impairment Induced by a High-Fat Diet

High-fat (HF) diet-induced neuroinflammation and cognitive decline in humans and animals have been associated with microbiota dysbiosis via the gut-brain axis. Our previous studies revealed that excretory-secretory products (ESPs) derived from the larval Echinococcus granulosus (E. granulosus) function as immunomodulators to reduce the inflammatory response, while the parasitic infection alleviates metabolic disorders in the host. However, whether ESPs can improve cognitive impairment under obese conditions remain unknown. This study aimed to investigate the effects of E. granulosus-derived ESPs on cognitive function and the microbiota-gut-brain axis in obese mice. We demonstrated that ESPs supplementation prevented HF diet-induced cognitive impairment, which was assessed behaviorally by nest building, object location, novel object recognition, temporal order memory, and Y-maze memory tests. In the hippocampus (HIP) and prefrontal cortex (PFC), ESPs suppressed neuroinflammation and HF diet-induced activation of the microglia and astrocytes. Moreover, ESPs supplementation improved the synaptic ultrastructural impairments and increased both pre- and postsynaptic protein levels in the HIP and PFC compared to the HF diet-treated group. In the colon, ESPs reversed the HF diet-induced gut barrier dysfunction, increased the thickness of colonic mucus, upregulated the expression of zonula occludens-1 (ZO-1), attenuated the translocation of bacterial endotoxins, and decreased the colon inflammation. Notably, ESPs supplementation alleviated the HF diet-induced microbiota dysbiosis. After clarifying the role of antibiotics in obese mice, we found that broad-spectrum antibiotic intervention abrogated the effects of ESPs on improving the gut microbiota dysbiosis and cognitive decline. Overall, the present study revealed for the first time that the parasite-derived ESPs alleviate gut microbiota dysbiosis and improve cognitive impairment induced by a high-fat diet. This finding suggests that parasite-derived molecules may be used to explore novel drug candidates against obesity-associated neurodegenerative diseases.

Mechanisms Involved in Microglial-Interceded Alzheimer's Disease and Nanocarrier-Based Treatment Approaches

Alzheimer's disease (AD) is a common neurodegenerative disorder accountable for dementia and cognitive dysfunction. The etiology of AD is complex and multifactorial in origin. The formation and deposition of amyloid-beta (Aβ), hyperphosphorylated tau protein, neuroinflammation, persistent oxidative stress, and alteration in signaling pathways have been extensively explored among the various etiological hallmarks. However, more recently, the immunogenic regulation of AD has been identified, and macroglial activation is considered a limiting factor in its etiological cascade. Macroglial activation causes neuroinflammation via modulation of the NLRP3/NF-kB/p38 MAPKs pathway and is also involved in tau pathology via modulation of the GSK-3β/p38 MAPK pathways. Additionally, microglial activation contributes to the discrete release of neurotransmitters and an altered neuronal synaptic plasticity. Therefore, activated microglial cells appear to be an emerging target for managing and treating AD. This review article discussed the pathology of microglial activation in AD and the role of various nanocarrier-based anti-Alzeihmenr's therapeutic approaches that can either reverse or inhibit this activation. Thus, as a targeted drug delivery system, nanocarrier approaches could emerge as a novel means to overcome existing AD therapy limitations.

Luteolin Suppresses Microglia Neuroinflammatory Responses and Relieves Inflammation-Induced Cognitive Impairments

Microglia-mediated neuroinflammation in response to injurious self and non-self-stimuli exerts detrimental effects on neurons, which may lead to cognitive impairment. Luteolin, a typical kind of natural flavonoid in honeysuckle, chrysanthemum, and Herba Schizonepetae, is widely recognized to be anti-inflammatory and antioxidant against peripheral inflammation. However, its protective effect against inflammation-induced cognitive impairment is currently unknown. In this paper, we investigated the relief potential of luteolin against lipopolysaccharide (LPS)-induced cognitive impairment and neuroinflammation and its possible anti-inflammatory mechanisms in lipopolysaccharide-stimulated BV2 microglia cells. In this study, luteolin ameliorated LPS-induced cognitive impairments, indicated by behavioral performance of neuroinflammatory model mice in Morris water maze tests. Protein analyses and histological examination also revealed protective effect of luteolin against neuronal damage, through inhibiting overproduction of inflammatory cytokines in both hippocampus and cortex of mice. We also observed luteolin in vitro significantly suppressed the levels of pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin-1 β (IL-1β), and inflammatory mediators like nitric oxide. Taken together, these results demonstrated luteolin was effective in alleviating cognitive impairment and limited neuronal damage via inhibiting the release of inflammatory mediators, suggesting luteolin is potential for further therapeutic research of neuroinflammation-related neurodegenerative diseases.

Natural medicine combined with nanobased topical delivery systems: a new strategy to treat psoriasis

Psoriasis, an autoimmune inflammatory skin disorder, is one of the commonest immune-mediated disease conditions affecting individuals globally. At the moment, the conventional methods applied against psoriasis treatment have various drawbacks involving limited efficacy, skin irritation, immunosuppression, etc. Therefore, it is important for scientists to find a more potent and alternative drug approach towards psoriasis therapeutics. Natural medicine still remains an important source for new drug discovery due to its therapeutical significance in various drug administration routes. However, the traditional formulation of topical therapies for psoriasis is limited in efficacy, which limits the use of natural medicine. Based on the aforementioned limitations, the use of nanocarriers in preparation of these topical herbal products could be tremendously beneficial in enhancing the efficacy of topical medications. Growing pieces of evidence have proposed that the utilization of nanocarriers in transdermal preparation as a prospective technique, with regards to better potency, directs drug absorption to site of action, and minimum toxicity effect respectively. In the course of this review, we emphasized the pathological mechanism of psoriasis, natural medicine formula, active components of natural medicine, and nanopreparations used in the treatment of psoriasis.

Evaluation of Anti-inflammatory Nutraceuticals in LPS-induced Mouse Neuroinflammation Model: An Update

It is known that peripheral infections, accompanied by inflammation, represent significant risk factors for the development of neurological disorders by modifying brain development or affecting normal brain aging. The acute effects of systemic inflammation on progressive and persistent brain damage and cognitive impairment are well documented. Anti-inflammatory therapies may have beneficial effects on the brain, and the protective properties of a wide range of synthetic and natural compounds have been extensively explored in recent years. In our previous review, we provided an extensive analysis of one of the most important and widely-used animal models of peripherally induced neuroinflammation and neurodegeneration - lipopolysaccharide (LPS)-treated mice. We addressed the data reproducibility in published research and summarized basic features and data on the therapeutic potential of various natural products, nutraceuticals, with known anti-inflammatory effects, for reducing neuroinflammation in this model. Here, recent data on the suitability of the LPS-induced murine neuroinflammation model for preclinical assessment of a large number of nutraceuticals belonging to different groups of natural products such as flavonoids, terpenes, non-flavonoid polyphenols, glycosides, heterocyclic compounds, organic acids, organosulfur compounds and xanthophylls, are summarized. Also, the proposed mechanisms of action of these molecules are discussed.

Aromatic-Turmerone Analogs Protect Dopaminergic Neurons in Midbrain Slice Cultures through Their Neuroprotective Activities

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. The inflammatory activation of microglia participates in dopaminergic neurodegeneration in PD. Therefore, chemicals that inhibit microglial activation are considered to have therapeutic potential for PD. Aromatic (ar)-turmerone is a main component of turmeric oil extracted from Curcuma longa and has anti-inflammatory activity in cultured microglia. The aims of the present study are (1) to investigate whether naturally occurring S-enantiomer of ar-turmerone (S-Tur) protects dopaminergic neurons in midbrain slice cultures and (2) to examine ar-turmerone analogs that have higher activities than S-Tur in inhibiting microglial activation and protecting dopaminergic neurons. R-enantiomer (R-Tur) and two analogs showed slightly higher anti-inflammatory effects in microglial BV2 cells. S- and R-Tur and these two analogs reversed dopaminergic neurodegeneration triggered by microglial activation in midbrain slice cultures. Unexpectedly, this neuroprotection was independent of the inhibition of microglial activation. Additionally, two analogs more potently inhibited dopaminergic neurodegeneration triggered by a neurotoxin, 1-methyl-4-phenylpyridinium, than S-Tur. Taken together, we identified two ar-turmerone analogs that directly and potently protected dopaminergic neurons. An investigation using dopaminergic neuronal precursor cells suggested the possible involvement of nuclear factor erythroid 2-related factor 2 in this neuroprotection.

β-Glucan from Lentinula edodes prevents cognitive impairments in high-fat diet-induced obese mice: involvement of colon-brain axis

Background

Long-term high fat (HF) diet intake can cause neuroinflammation and cognitive decline through the gut-brain axis. (1, 3)/(1, 6)-β-glucan, an edible polysaccharide isolated from medical mushroom, Lentinula edodes (L. edodes), has the potential to remodel gut microbiota. However, the effects of L. edodes derived β-glucan against HF diet-induced neuroinflammation and cognitive decline remain unknown. This study aimed to evaluate the neuroprotective effect and mechanism of dietary L edodes β-glucan supplementation against the obesity-associated cognitive decline in mice fed by a HF diet.

Methods

C57BL/6J male mice were fed with either a lab chow (LC), HF or HF with L. edodes β-glucan supplementation diets for 7 days (short-term) or 15 weeks (long-term). Cognitive behavior was examined; blood, cecum content, colon and brain were collected to evaluate metabolic parameters, endotoxin, gut microbiota, colon, and brain pathology.

Results

We reported that short-term and long-term L. edodes β-glucan supplementation prevented the gut microbial composition shift induced by the HF diet. Long-term L. edodes β-glucan supplementation prevented the HF diet-induced recognition memory impairment assessed by behavioral tests (the temporal order memory, novel object recognition and Y-maze tests). In the prefrontal cortex and hippocampus, the β-glucan supplementation ameliorated the alteration of synaptic ultrastructure, neuroinflammation and brain-derived neurotrophic factor (BDNF) deficits induced by HF diet. Furthermore, the β-glucan supplementation increased the mucosal thickness, upregulated the expression of tight junction protein occludin, decreased the plasma LPS level, and inhibited the proinflammatory macrophage accumulation in the colon of mice fed by HF diet.

Conclusions

This study revealed that L. edodes β-glucan prevents cognitive impairments induced by the HF diet, which may occur via colon-brain axis improvement. The finding suggested that dietary L. edodes β-glucan supplementation may be an effective nutritional strategy to prevent obesity-associated cognitive decline.

Curcuma longa L. Rhizome Essential Oil from Extraction to Its Agri-Food Applications. A Review

Curcuma longa L. rhizome essential oil is a valuable product in pharmaceutical industry due to its wide beneficial health effects. Novel applications in the agri-food industry where more sustainable extraction processes are required currently and safer substances are claimed for the consumer are being investigated. This review provides information regarding the conventional and recent extraction methods of C. longa rhizome oil, their characteristics and suitability to be applied at the industrial scale. In addition, variations in the chemical composition of C. longa rhizome and leaf essential oils regarding intrinsic and extrinsic factors and extraction methods are also analysed in order to select the most proper to obtain the most efficient activity. Finally, the potential applications of C. longa rhizome oil in the agri-food industry, such as antimicrobial, weedicide and a food preservative agent, are included. Regarding the data, C. longa rhizome essential oil may play a special role in the agri-food industry; however, further research to determine the application threshold so as not to damage crops or affect the organoleptic properties of food products, as well as efficient encapsulation techniques, are necessary for its implementation in global agriculture.

Traditional Herbal Medicines Against CNS Disorders from Bangladesh

The majority of the population in Bangladesh uses traditional plant-based medicines to manage various ailments, including central nervous system (CNS) disorders. This review presents ethnobotanical information and relevant scientific studies on plants used in traditional healthcare for the management of various CNS disorders in Bangladesh. The information on the medicinal plants of Bangladesh effective against CNS disorders published in scientific journals, books, and reports was compiled from different electronic databases using specific key words. The present article provides comprehensive information on a total of 224 medicinal plant species belonging to 81 families used for the treatment of CNS disorders by the various peoples of Bangladesh. In total, we reviewed more than 290 relevant papers. In this study, leaves were found as the most often used plant organ, followed by roots, fruits, whole plants, barks, seeds, stems, rhizomes, and flowers. The Fabaceae family contributes the highest number of used species, followed by Rubiaceae, Lamiaceae, Cucurbitaceae, Vitaceae, Euphorbiaceae, Malvaceae, and Zingiberaceae. The most frequently used species (in decreasing order) are Asparagus racemosus, Centella asiatica, Stephania japonica, Aegle marmelos, Coccinia grandis, Tabernaemontana divaricata, Bacopa monnieri, Abroma augusta, and Scoparia dulcis. This review may serve as a starting point for a rational search for neuroactive natural products against CNS disorders within the Flora of Bangladesh.

Neuroprotective effects of aromatic turmerone on activity deprivation-induced apoptosis in cerebellar granule neurons

Ar-turmerone, which is a major bioactive component found in the essential oil derived from Curcuma longa, has been reported to inhibit proliferation and induce apoptosis in cancer cell lines. Recently, ar-turmerone has been reported to increase the proliferation of neuronal stem cells, in contrast to its actions in cancer cells. These observations raise the possibility that ar-turmerone serves specific functions in neuronal cell lineages. However, the effects of ar-turmerone on postmitotic neurons remain elusive. In the present study, we investigated the neuroprotective functions of ar-turmerone in primary cerebellar granule neuronal cultures. We found that ar-turmerone increased the survival of neurons following activity deprivation. Consistently, the induction of cleaved caspase-3, a hallmark of apoptosis, was prevented by ar-turmerone, although neither the level of reactive oxygen species nor the mitochondrial membrane potential was affected. This study reports a neuroprotective function for ar-turmerone, providing new insights into the potential therapeutic applications of ar-turmerone for neurological disorders.

Banhasasim-Tang Attenuates Lipopolysaccharide-Induced Cognitive Impairment by Suppressing Neuroinflammation in Mice

Banhasasim-tang (BHS) is an herbal medicine that has been widely used in East Asia to treat various symptoms associated with upper abdomen swelling. BHS has not been studied previously for neuroinflammation or cognitive disorder. Here, we use a lipopolysaccharide (LPS) model to investigate the effects and mechanisms of BHS in neuroinflammation and cognitive impairment of mice. We used a mouse model of LPS-induced cognitive impairment and neuroinflammation and examined whether administration of BHS prevents these deficits via Morris water maze test, passive avoidance test, histopathological analysis, Western blotting, and real-time reverse transcription polymerase chain reaction (RT-qPCR). We found via behavioral tests that BHS treatment effectively prevented LPS-induced memory loss and neuronal damage in mice. Histopathological analysis of mouse brains revealed that BHS inhibited LPS-induced expression of microglial and astrocyte activation markers. Furthermore, BHS inhibits the production of markers related to neurodegeneration, amyloidogenesis, and inflammation, and mRNA expression of inflammatory mediators in mouse brain tissue. Additionally, BHS pretreatment effectively inhibited generation of inflammatory factors and pathways in BV2 microglial cells stimulated by LPS. These observations indicate that BHS is effective in preventing cognitive impairment caused by neuroinflammation and has strong potential as a candidate treatment for neuronal inflammatory diseases.

Curdlan Prevents the Cognitive Deficits Induced by a High-Fat Diet in Mice via the Gut-Brain Axis

A high-fat (HF) diet is a major predisposing factor of neuroinflammation and cognitive deficits. Recently, changes in the gut microbiota have been associated with neuroinflammation and cognitive impairment, through the gut-brain axis. Curdlan, a bacterial polysaccharide widely used as food additive, has the potential to alter the composition of the microbiota and improve the gut-brain axis. However, the effects of curdlan against HF diet-induced neuroinflammation and cognitive decline have not been investigated. We aimed to evaluate the neuroprotective effect and mechanism of dietary curdlan supplementation against the obesity-associated cognitive decline observed in mice fed a HF diet. C57Bl/6J male mice were fed with either a control, HF, or HF with curdlan supplementation diets for 7 days (acute) or 15 weeks (chronic). We found that acute curdlan supplementation prevented the gut microbial composition shift induced by HF diet. Chronic curdlan supplementation prevented cognitive declines induced by HF diet. In addition, curdlan protected against the HF diet-induced abnormities in colonic permeability, hyperendotoxemia, and colonic inflammation. Furthermore, in the prefrontal cortex (PFC) and hippocampus, curdlan mitigated microgliosis, neuroinflammation, and synaptic impairments induced by a HF diet. Thus, curdlan—as a food additive and prebiotic—can prevent cognitive deficits induced by HF diet via the colon-brain axis.

TLR2/EGFR Are Two Sensors for pBD3 and pEP2C Induction by Sodium Butyrate Independent of HDAC Inhibition

Host defense peptides (HDPs) are vital mucosal defense effectors of the innate immune response. The expression of HDPs is inducible in epithelial cells by potent endogenous inducers. Herein, our results demonstrate that sodium butyrate (NaB) induces the expression of porcine β-defensin-3 (pBD3) and porcine epididymis protein 2 splicing variant C (pEP2C) in a dose- and time-dependent manner, without modifying the production of proinflammatory cytokines, in porcine intestinal epithelial cells (IPEC J2). Moreover, NaB promotes toll-like receptor 2 (TLR2) expression. TLR2 silencing inhibits the pBD3 and pEP2C expression induced by NaB but does not abolish the histone deacetylase (HDAC) inhibitory activity of NaB. We found that NaB activated the nuclear factor-κB (NF-κB) pathway. Importantly, the degree of cell confluence governs the regulatory responses but does not affect the HDAC activity of NaB. Furthermore, epidermal growth factor receptor (EGFR), but not the mitogen-activated protein kinase (MAPK) pathway, is vital during the NaB-induced pBD3 and pEP2C regulation process. We also demonstrated that pBD3 overexpression increases interleukin-18 levels. This study showed that NaB simultaneously induces pBD3 and pEP2C via TLR2 and EGFR in IPEC J2 cells without increasing the risk of a harmful inflammatory response.

6-O-angeloylplenolin exerts neuroprotection against lipopolysaccharide-induced neuroinflammation in vitro and in vivo

Neuroinflammation is one of the critical events in neurodegenerative diseases, whereas microglia play an important role in the pathogenesis of neuroinflammation. In this study, we investigated the effects of a natural sesquiterpene lactone, 6-O-angeloylplenolin (6-OAP), isolated from the traditional Chinese medicine Centipeda minima (L.) A.Br., on neuroinflammation and the underlying mechanisms. We showed that treatment with lipopolysaccharide (LPS) caused activation of BV2 and primary microglial cells and development of neuroinflammation in vitro, evidenced by increased production of inflammatory cytokines TNF-α and IL-1β, the phosphorylation and nuclear translocation of NF-κB, and the transcriptional upregulation of COX-2 and iNOS, leading to increased production of proinflammatory factors NO and PGE₂. Moreover, LPS treatment induced oxidative stress through increasing the expression levels of NOX2 and NOX4. Pretreatment with 6-OAP (0.5−4 μM) dose-dependently attenuated LPS-induced NF-κB activation and oxidative stress, thus suppressed neuroinflammation in the cells. In a mouse model of LPS-induced neuroinflammation, 6-OAP (5−20 mg·kg⁻¹·d⁻¹, ip, for 7 days before LPS injection) dose-dependently inhibited the production of inflammatory cytokines, the activation of the NF-κB signaling pathway, and the expression of inflammatory enzymes in brain tissues. 6-OAP pretreatment significantly ameliorated the activation of microglia and astrocytes in the brains. 6-OAP at a high dose caused a much stronger antineuroinflammatory effect than dexamethansone (DEX). Furthermore, we demonstrated that 6-OAP pretreatment could inhibit LPS-induced neurite and synaptic loss in vitro and in vivo. In conclusion, our results demonstrate that 6-OAP exerts antineuroinflammatory effects and can be considered a novel drug candidate for the treatment of neuroinflammatory diseases.

Potential link between the RagA-mTOR-p70S6K axis and depressive-behaviors during bacterial liposaccharide challenge

BACKGROUND

Bacterial infection is a potential risk factor for depression. However, little is known about the mechanistic link between bacterial endotoxin and depressive-like behaviors. The aim of the present study was to clarify whether liposaccharide (LPS) could induce depressive-like behaviors in mice via sequentially activating small GTPase RagA, mammalian target of rapamycin (mTOR), and p70S6K.

METHODS

C57BL/6 N mice were treated with 0.83 mg/kg LPS by intraperitoneal injection for 24 h. The animals were assessed for depressive-like behaviors by forced swim test and tail suspension test. The expression levels of RagA, mTOR, and p70S6K were determined in mice, primary cortical neurons, neural stem cells, and PC12 cells.

RESULTS

LPS effectively induced depressive-like behaviors in mice. Biochemical examination revealed that LPS not only upregulated RagA expression but also activated mTOR/p70S6K pathway in mouse brains. LPS challenge also achieved a similar effect in primary cortical neurons, neural stem cells, and PC12 cells. Following the silencing of RagA expression with specific siRNA, LPS failed to induce mTORC1 translocation to the lysosomal membranes in PC12 cells. These results suggested that LPS might sequentially upregulate RagA and activate mTOR and p70S6K pathways in mice and neural stem cells.

CONCLUSIONS

This study for the first time demonstrated that LPS might induce depressive-like behaviors in mice via the upregulation of RagA and subsequent activation of mTOR/p70S6K pathway. Such information may highlight the RagA-mTOR-p70S6K signaling cascade as a novel therapeutic target for the development of new anti-depressant therapeutics.

Geraniin Attenuates Lipopolysaccharide-Induced Cognitive Impairment in Mice by Inhibiting Toll-Like Receptor 4 Activation

Geraniin has been reported to possess potent anti-inflammatory properties and to modulate the macrophage polarization. This study sought to evaluate the protective effects and underlying mechanisms of geraniin on lipopolysaccharide (LPS)-induced neuroinflammation and neurobiological alternations as well as cognitive impairment. Daily intragastrical administration with geraniin (20 mg kg^-1 day^-1) for 14 days significantly prolonged the duration in the target quadrant (26.53 ± 2.03 versus 37.09 ± 3.27%; p < 0.05) and increased crossing-target number (1.93 ± 0.22 versus 3.08 ± 0.17; p < 0.01) in the probe test of LPS-treated mice. Geraniin also ameliorated LPS-elicited neural/synaptic impairments and decreased levels of LPS-induced Aβ generation (p < 0.05), amyloid precursor protein (APP) (p < 0.05) and β-site amyloid precursor protein cleavage enzyme 1 (BACE1) (p < 0.05). Furthermore, geraniin suppressed the production of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) (9.85 ± 0.58 versus 5.20 ± 0.52 pg/mg of protein; p < 0.01), interleukin (IL)-1β (16.31 ± 0.67 versus 8.62 ± 0.46 pg/mg of protein; p < 0.01), and IL-6 (12.12 ± 0.45 versus 7.43 ± 0.32 pg/mg of protein; p < 0.05), and inhibited glial cell activation. Moreover, geraniin effectively polarized the microglia toward an anti-inflammatory M2 phenotype. Further study revealed that geraniin targeted toll-like receptor 4 (TLR4)-mediated signaling and decreased the production of pro-inflammatory cytokines in BV-2 microglial cells. These results indicate that geraniin mitigates LPS-elicited neural/synaptic neurodegeneration, amyloidogenesis, neuroinflammation, and cognitive impairment and suggest geraniin as a therapeutic option for neuroinflammation-associated neurological disorders, such as Alzheimer's disease.

Suppressive effect of glycyrrhizic acid against lipopolysaccharide-induced neuroinflammation and cognitive impairment in C57 mice via toll-like receptor 4 signaling pathway

Background

Glycyrrhizinic acid (GA), a major active ingredient enriched in the roots of licorice, possesses well-confirmed anti-inflammatory effects.

Objective

To evaluate the underlying mechanisms of GA against lipopolysaccharide (LPS)-induced chronic neuroinflammation and memory impairment.

Design

We explored to investigate the effects of GA on neuroinflammation and memory impairment in an LPS-induced Alzheimer’s mouse model.

Results

Data of micro-PET/CT imaging and morris water maze test suggested that GA, when administrated orally, could reverse LPS-induced abnormalized glucose intake and metabolism in the brain and alleviate LPS-induced memory loss and cognitive defects in mice. Histological and immunohistochemical staining results revealed that GA treatment suppressed overexpressions of pro-inflammatory cytokines of IL-1 β and TNF-α in the brain of C57 mice by inhibiting toll-like receptor 4 (TLR4) signaling pathway activation.

Conclusion

Our findings suggest that GA may be a therapeutic agent for the treatment of neuroinflammation and cognitive impairment.

Screening of herbal extracts for TLR2- and TLR4-dependent anti-inflammatory effects

Herbal extracts represent an ample source of natural compounds, with potential to be used in improving human health. There is a growing interest in using natural extracts as possible new treatment strategies for inflammatory diseases. We therefore aimed at identifying herbal extracts that affect inflammatory signaling pathways through toll-like receptors (TLRs), TLR2 and TLR4. Ninety-nine ethanolic extracts were screened in THP-1 monocytes and HeLa-TLR4 transfected reporter cells for their effects on stimulated TLR2 and TLR4 signaling pathways. The 28 identified anti-inflammatory extracts were tested in comparative assays of stimulated HEK-TLR2 and HEK-TLR4 transfected reporter cells to differentiate between direct TLR4 antagonistic effects and interference with downstream signaling cascades. Furthermore, the ten most effective anti-inflammatory extracts were tested on their ability to inhibit nuclear factor-κB (NF-κB) translocation in HeLa-TLR4 transfected reporter cell lines and for their ability to repolarize M1-type macrophages. Ethanolic extracts which showed the highest anti-inflammatory potential, up to a complete inhibition of pro-inflammatory cytokine production were Castanea sativa leaves, Cinchona pubescens bark, Cinnamomum verum bark, Salix alba bark, Rheum palmatum root, Alchemilla vulgaris plant, Humulus lupulus cones, Vaccinium myrtillus berries, Curcuma longa root and Arctostaphylos uva-ursi leaves. Moreover, all tested extracts mitigated not only TLR4, but also TLR2 signaling pathways. Seven of them additionally inhibited translocation of NF-κB into the nucleus. Two of the extracts showed impact on repolarization of pro-inflammatory M1-type to anti-inflammatory M2-type macrophages. Several promising anti-inflammatory herbal extracts were identified in this study, including extracts with previously unknown influence on key TLR signaling pathways and macrophage repolarization, serving as a basis for novel lead compound identification.

Glycyrrhizic acid from licorice down-regulates inflammatory responses via blocking MAPK and PI3K/Akt-dependent NF-κB signalling pathways in TPA-induced skin inflammation

Glycyrrhizinic acid (GA), a principal component derived from licorice which is used extensively as a natural sweetener and traditional folk herbal medicine, is attracting considerable attention because of its broad range of bioactivities. However, the anti-inflammatory mechanism of GA on 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated skin inflammation has not been elucidated. Herein, we investigated the anti-inflammatory activity of GA by using a TPA-induced mouse ear model. It was indicated that GA, applied topically onto mouse ears, effectively inhibited the TPA-mediated expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner, respectively. Mechanistic investigations demonstrated that GA down-regulated the expressions of IκBα and p65 and blocked the phosphorylation of IκBα and p65 in TPA-induced mouse skin. Moreover, GA significantly inhibited the TPA-mediated activation of extracellular signal-regulated kinase (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)/Akt, which are upstream of nuclear factor-kB (NF-κB). Taken together, these results indicated that GA, being of natural origin, may be a potential agent for preventing inflammatory diseases.