Urolithins Attenuate LPS-Induced Neuroinflammation in BV2Microglia via MAPK, Akt, and NF-κB Signaling Pathways

The ellagitannin metabolite urolithin C attenuated cognitive impairment by inhibiting neuroinflammation via downregulation of MAPK/NF-kB signaling pathways in aging mice

The current study aimed to evaluate the preventive effects of urolithin C (Uro C), a gut microbial metabolite of ellagitannins on D-galactose (D-gal)-induced brain damage during the aging process and to elucidate the underlying mechanisms. In our study, the protective effect of Uro C on D-gal-induced BV2 microglia cell-mediated neuroinflammation damage in primary cortical neurons in vitro was confirmed. The results in an aging model in vivo induced by D-gal demonstrated that Uro C prevented D-gal-induced memory impairment, long-term potentiation (LTP) damage, and synaptic dysfunction through behavioral, electrophysiological, and histological examinations. Additionally, amyloidogenesis was observed in the central nervous system. The findings indicated that Uro C exhibited a preventive effect on the D-gal-induced elevation of β-amyloid (1-42 specific) (Aβ1-42) accumulation, APP levels, ABCE1 levels, and the equilibrium of the cholinergic system in the aging mouse brain. Moreover, Uro C demonstrated downregulation of D-gal-induced glial overactivation through inhibition of the MAPK/NF-kB pathway. This resulted in the regulation of inflammatory mediators and cytokines, including iNOS, IL-6, IL-1β, and TNF-ɑ, in the mouse brain and BV2 microglial cells. Taken together, our results suggested that Uro C treatment could effectively mitigate the D-gal-induced memory impairment and amyloidogenesis, and the underlying mechanism might be tightly related to the improvement of neuroinflammation by suppressing the MAPK/NF-kB pathway, indicating Uro C might be an alternative and promising agent for the treatment of aging and age-associated brain diseases.

Experimental peri-implantitis induces neuroinflammation: An exploratory study in rats

PURPOSE

Cumulating evidence supports the close association between periodontal diseases, neuroinflammation and neurodegenerative pathologies, except for peri-implantitis (PI). Thus, this study explored the association between experimental PI and neuropathological changes in the rat brain.

MATERIALS AND METHODS

After bilateral first molars extraction, experimental PI was induced at titanium implants placed in the maxillae by lipopolysaccharide injections and ligature placement. Following 28-weeks of disease progression, the maxillae and brains were retrieved from 6 rats. Healthy brains from 3 rats were used as control. Brains were analyzed by immunohistochemistry to detect signs of neuroinflammation (interleukin (IL)-6 and tumor necrosis factor (TNF)-α)), microglial activation (IBA-1) and astrogliosis (GFAP). To explore signs of neurodegeneration, hematoxylin/eosin and Nissl stainings were used. Also, four different antibodies against amyloid beta (Aβ 1-42) were tested.

RESULTS

Chronic PI lesions showed peri-implant bone resorption accompanied by large inflammatory infiltrates. IL-6+ and TNF-α+ cells were found within the CA1 and Dentate Gyrus regions of the hippocampus of the PI-affected group, while almost no immune-positivity was detected in the control (p < 0.05). Detection of activated GFAP+ microglia and IBA-1+ astrocytes surface were significantly higher at the CA areas, and cerebral cortex of the PI-affected group, in comparison with control (p < 0.05). Shrunk neurons with pyknotic nuclei were inconsistently found among the PI-affected group, and these were almost not detected in control. No positive Aβ reactivity was detected in any of the samples.

CONCLUSION

Chronic experimental PI lesions led to an increased detection of IL-6 and TNF-α, GFAP+ microgliosis and IBA-1+ astrocytosis, and in some cases, neurodegeneration, in the rat brain.

Rhein inhibits M1 polarization of BV2 microglia through MAPK/IκB signalling pathway and reduces neurotoxicity caused by neuroinflammation

BACKGROUND

Rhein is an anthraquinone compound with anti-inflammatory pharmacological activity. It has been found to play a neuroprotective role in neurological diseases, but the neuroprotective mechanism of rhein remains unclear.

METHODS

SH-SY5Y cells serving as neuron-like cells and BV2 microglia were used. The toxicity of rhein on BV2 microglia and the viability of SH-SY5Y cells were measured by CCK-8 assay. The mRNA expression and secretion of pro-inflammatory cytokines were detected by qPCR and ELISA. Iba1, CD86 and pathway signalling protein in BV2 microglia were assessed by Western blot and immunofluorescence. Apoptosis of SH-SY5Y cells exposed to neuroinflammation was analysed through flow cytometry.

RESULTS

Rhein inhibited MAPK/IκB signalling pathways. Further studies revealed that rhein inhibited the production of pro-inflammatory cytokines TNF-α, IL-6, IL-1β and iNOS in BV2 cells and also inhibited the expression of M1 polarization markers Iba1 and CD86 in BV2 cells. Furthermore, rhein reduced the apoptotic rate and restored cell viability of SH-SY5Y cells exposed to neuroinflammation.

CONCLUSIONS

Our study demonstrated that rhein inhibited microglia M1 polarization via MAPK/IκB signalling pathway and protected nerve cells through suppressing neuroinflammation.

Strawberry (Fragaria x Ananassa) intake on human health and disease outcomes: a comprehensive literature review

Strawberries provide a number of potential health promoting phytonutrients to include phenolics, polyphenols, fiber, micronutrients and vitamins. The objective of this review is to provide a comprehensive summary of recent human studies pertaining to the intake of strawberry and strawberry phytonutrients on human health. A literature search conducted through PubMed and Cochrane databases consolidated studies focusing on the effects of strawberry intake on human health. Articles were reviewed considering pre-determined inclusion and exclusion criteria, including experimental or observational studies that focused on health outcomes, and utilized whole strawberries or freeze-dried strawberry powder (FDSP), published between 2000-2023. Of the 60 articles included in this review, 47 were clinical trials, while 13 were observational studies. A majority of these studies reported on the influence of strawberry intake on cardiometabolic outcomes. Study designs included those examining the influence of strawberry intake during the postprandial period, short-term trials randomized with a control, or a single arm intake period controlling with a low polyphenolic diet or no strawberry intake. A smaller proportion of studies included in this review examined the influence of strawberry intake on additional outcomes of aging including bone and brain health, and cancer risk. Data support that the inclusion of strawberries into the diet can have positive impacts during the postprandial period, with daily intake improving outcomes of lipid metabolism and inflammation in those at increased cardiovascular risk.

Regulation of Intestinal Inflammation by Walnut-Derived Bioactive Compounds

Walnuts (Juglans regia L.) have shown promising effects in terms of ameliorating inflammatory bowel disease (IBD), attributed to their abundant bioactive compounds. This review comprehensively illustrates the key mechanisms underlying the therapeutic potential of walnuts in IBD management, including the modulation of intestinal mucosa permeability, the regulation of inflammatory pathways (such as NF-kB, COX/COX2, MAPCK/MAPK, and iNOS/NOS), relieving oxidative stress, and the modulation of gut microbiota. Furthermore, we highlight walnut-derived anti-inflammatory compounds, such as polyunsaturated fatty acids (PUFA; e.g., ω-3 PUFA), tocopherols, phytosterols, sphingolipids, phospholipids, phenolic compounds, flavonoids, and tannins. We also discuss unique anti-inflammatory compounds such as peptides and polysaccharides, including their extraction and preparation methods. Our review provides a theoretical foundation for dietary walnut supplementation in IBD management and provides guidance for academia and industry. In future, research should focus on the targeted isolation and purification of walnut-derived anti-inflammatory compounds or optimizing extraction methods to enhance their yields, thereby helping the food industry to develop dietary supplements or walnut-derived functional foods tailored for IBD patients.

Recent advances in anti-inflammation via AMPK activation

Inflammation is a complex physiological phenomenon, which is the body's defensive response, but abnormal inflammation can have adverse effects, and many diseases are related to the inflammatory response. AMPK, as a key sensor of cellular energy status, plays a crucial role in regulating cellular energy homeostasis and glycolipid metabolism. In recent years, the anti-inflammation effect of AMPK and related signalling cascade has begun to enter everyone's field of vision - not least the impact on metabolic diseases. A great number of studies have shown that anti-inflammatory drugs work through AMPK and related pathways. Herein, this article summarises recent advances in compounds that show anti-inflammatory effects by activating AMPK and attempts to comment on them.

Rhein alleviates MPTP-induced Parkinson's disease by suppressing neuroinflammation via MAPK/IκB pathway

Background

Parkinson's disease (PD) is a common neurodegenerative disease with a rapid increase in incidence in recent years. Existing treatments cannot slow or stop the progression of PD. It was proposed that neuroinflammation leads to neuronal death, making targeting neuroinflammation a promising therapeutic strategy. Our previous studies have demonstrated that rhein protects neurons in vitro by inhibiting neuroinflammation, and it has been found to exhibit neuroprotective effects in Alzheimer's disease and epilepsy, but its neuroprotective mechanisms and effects on PD are still unclear.

Methods

PD animal model was induced by 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP). ELISA, RT-qPCR, western blot and Immunofluorescence were used to detect the levels of inflammatory cytokines and M1 polarization markers. The protein expression levels of signaling pathways were measured by western blot. Hematoxylin-eosin (HE) staining showed that rhein did not damage the liver and kidney. Two behavioral tests, pole test and rotarod test, were used to evaluate the improvement effect of rhein on movement disorders. The number of neurons in the substantia nigra was evaluated by Nissl staining. Immunohistochemistry and western blot were used to detect tyrosine hydroxylase (TH) and α-synuclein.

Results

Rhein inhibited the activation of MAPK/IκB signaling pathway and reduced the levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and M1 polarization markers of microglia in vivo. In a mouse model of PD, rhein ameliorated movement disorders, reduced dopaminergic neuron damage and α-synuclein deposition.

Conclusion

Rhein inhibits neuroinflammation through MAPK/IκB signaling pathway, thereby reducing neurodegeneration, α-synuclein deposition, and improving movement disorders in Parkinson's disease.

Urolithin A improves Alzheimer's disease cognition and restores mitophagy and lysosomal functions

BACKGROUND

Compromised autophagy, including impaired mitophagy and lysosomal function, plays pivotal roles in Alzheimer's disease (AD). Urolithin A (UA) is a gut microbial metabolite of ellagic acid that stimulates mitophagy. The effects of UA's long-term treatment of AD and mechanisms of action are unknown.

METHODS

We addressed these questions in three mouse models of AD with behavioral, electrophysiological, biochemical, and bioinformatic approaches.

RESULTS

Long-term UA treatment significantly improved learning, memory, and olfactory function in different AD transgenic mice. UA also reduced amyloid beta (Aβ) and tau pathologies and enhanced long-term potentiation. UA induced mitophagy via increasing lysosomal functions. UA improved cellular lysosomal function and normalized lysosomal cathepsins, primarily cathepsin Z, to restore lysosomal function in AD, indicating the critical role of cathepsins in UA-induced therapeutic effects on AD.

CONCLUSIONS

Our study highlights the importance of lysosomal dysfunction in AD etiology and points to the high translational potential of UA.

HIGHLIGHTS

Long-term urolithin A (UA) treatment improved learning, memory, and olfactory function in Alzheimer's disease (AD) mice. UA restored lysosomal functions in part by regulating cathepsin Z (Ctsz) protein. UA modulates immune responses and AD-specific pathophysiological pathways.

Modulatory Effects of Phytochemicals on Gut-Brain Axis: Therapeutic Implication

This article explores the potential therapeutic implications of phytochemicals on the gut-brain axis (GBA), which serves as a communication network between the central nervous system and the enteric nervous system. Phytochemicals, which are compounds derived from plants, have been shown to interact with the gut microbiota, immune system, and neurotransmitter systems, thereby influencing brain function. Phytochemicals such as polyphenols, carotenoids, flavonoids, and terpenoids have been identified as having potential therapeutic implications for various neurological disorders. The GBA plays a critical role in the development and progression of various neurological disorders, including Parkinson's disease, multiple sclerosis, depression, anxiety, and autism spectrum disorders. Dysbiosis, or an imbalance in gut microbiota composition, has been associated with a range of neurological disorders, suggesting that modulating the gut microbiota may have potential therapeutic implications for these conditions. Although these findings are promising, further research is needed to elucidate the optimal use of phytochemicals in neurological disorder treatment, as well as their potential interactions with other medications. The literature review search was conducted using predefined search terms such as phytochemicals, gut-brain axis, neurodegenerative, and Parkinson in PubMed, Embase, and the Cochrane library.

Camellia sinensis polysaccharide attenuates inflammatory responses via the ROS-mediated pathway by endocytosis

Polysaccharide CSTPs extracted from Camellia sinensis tea-leaves possessed unique against oxidative damage by scavenging ROS. Herein, acid tea polysaccharide CSTPs-2 with tightly packed molecular structure was isolated, purified and characterized in this research. Furthermore, the effects of CSTPs-2 on ROS-involved inflammatory responses and its underlying mechanisms were investigated. The results suggest that CSTPs-2 dramatically reduced the inflammatory cytokines overexpression and LPS-stimulated cell damage. CSTPs-2 could trigger the dephosphorylation of downstream AKT/MAPK/NF-κB signaling proteins and inhibit nuclear transfer of p-NF-κB to regulate the synthesis and release of inflammatory mediators in LPS-stimulated cells by ROS scavenging. Importantly, the impact of CSTPs-2 in downregulating pro-inflammatory cytokines and mitigating ROS overproduction is associated with clathrin- or caveolae-mediated endocytosis uptake mechanisms, rather than TLR-4 receptor-mediated endocytosis. This study presents a novel perspective for investigating the cellular uptake mechanism of polysaccharides in the context of anti-inflammatory mechanisms.

Neuroinflammation of Microglial Regulation in Alzheimer's Disease: Therapeutic Approaches

Alzheimer's disease (AD) is a complex degenerative disease of the central nervous system that is clinically characterized by a progressive decline in memory and cognitive function. The pathogenesis of AD is intricate and not yet fully understood. Neuroinflammation, particularly microglial activation-mediated neuroinflammation, is believed to play a crucial role in increasing the risk, triggering the onset, and hastening the progression of AD. Modulating microglial activation and regulating microglial energy metabolic disorder are seen as promising strategies to intervene in AD. The application of anti-inflammatory drugs and the targeting of microglia for the prevention and treatment of AD has emerged as a new area of research interest. This article provides a comprehensive review of the role of neuroinflammation of microglial regulation in the development of AD, exploring the connection between microglial energy metabolic disorder, neuroinflammation, and AD development. Additionally, the advancements in anti-inflammatory and microglia-regulating therapies for AD are discussed.

The effects of urolithin A on poly I:C-induced microglial activation

Neuroinflammation can be triggered by various stimuli, including viral infections. Viruses can directly invade the brain and infect neuronal cells or indirectly trigger a "cytokine storm" in the periphery that eventually leads to microglial activation in the brain. While this initial activation of microglial cells is important for viral clearance, chronic activation leads to excessive inflammation and oxidative stress, which can be neurotoxic. Remarkebly, recent studies have shown that certain viruses such as influenza A virus, coronavirus, herpes virus and Epstein-Barr virus may be involved in the development of neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Therefore, it is important to find therapeutic strategies against chronic neuroinflammation triggered by viral infections. Here, we investigated the effects of urolithin A (UA) on microglial activation in vitro induced by a viral mimetic, poly I:C, in a triple co-culture system of neurons, astrocytes and microglial cells. Immunocytochemistry was used to perform a comprehensive single-cell analysis of the morphological changes of microglia as an indicator of their reactive state. Treatment with UA significantly prevented the poly I:C-induced reactive state of microglia, which was characterized by increased expression of the microglial activation markers CD68 and IBA-1. UA restored the poly I:C-induced morphology by restoring microglial ramification. In addition, UA was able to reduce the release of the pro-inflammatory mediators CCL2, TNF-α, and IL-1β and showed a trend toward attenuation of cellular ROS production in poly I:C-treated cultures. Overall, this study suggests that UA as a component of a healthy diet may help prevent virus-induced neuroinflammation and may have therapeutic potential for future studies to prevent or treat neurodegenerative diseases by targeting the associated neuroinflammatory processes.

Exosomes secreted from induced pluripotent stem cell ameliorate the lipopolysaccharide induced neuroinflammatory response via lncRNA-0949

PURPOSE

To study the effect of exosomes derived from the induced pluripotent stem cells (iPSCs) in the neuroinflammatory response of microglia caused by lipopolysaccharide (LPS) and reveal the potential underlying mechanism.

METHODS

A permanent microglia cell line HMO6 was activated by LPS. The features of exosomes were analyzed by nano flow cytometry, Western blot and transmission electron microscope. The RNA-seq was used to analyze the difference of noncoding RNA profiles between iPSC-Exos and HMO6 derived exosomes and proved that long no-coding RNA (lncRNA-0949) was highly expressed in the iPSC-Exos. Activated HMO6 cells were cocultured with iPSC-Exos in which lncRNA-0949 was overexpressed, knocked down or normally expressed. Quantitative real-time polymerase chain reaction (RT-qPCR), Enzyme-Linked Immunosorbent Assay and Western blot assay were adopted to analyze RNA and protein expression of inflammatory factors in HMO6 cells.

RESULTS

The oxidative stress and inflammatory response of microglia were significantly attenuated with the iPSC derived exosomes treatment. LncRNA-0949 was effectively delivered into the HMO6 cells through the iPSC-Exos, which largely alleviated the production of malondialdehyde, IL-6, IL-1β and TNF-α in HMO6 cells. Overexpression of lncRNA-0949 could enhance the anti-inflammatory effect of the iPSC-Exos, and knock-down of lncRNA-0949 impaired this availability.

CONCLUSION

According to our results, lncRNA-0949 enriched exosomes from iPSC could potentially be used as a therapeutic strategy to prevent/treat neuroinflammatory diseases.

Quality markers of Dajianzhong decoction based on multicomponent qualitative and quantitative analysis combined with network pharmacology and chemometric analysis

INTRODUCTION

Dajianzhong decoction (DJZD), a classic famous prescription, has a long history of medicinal application. Modern studies have demonstrated its clinical utility in the treatment of postoperative ileus (POI). But none of the current quality evaluation methods for this compound is associated with efficacy.

OBJECTIVES

This study aimed to identify the quality markers (Q-Markers) connected to the treatment of POI in DJZD.

METHODOLOGY

Ultra-performance liquid chromatography quadrupole Exactive Orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) was used to identify the main constituents in DJZD. Based on the qualitative results obtained by fingerprinting, chemical pattern recognition (CPR) was used to analyse the key components affecting the quality and finally to establish the network of the active ingredients in DJZD with POI.

RESULTS

A total of 64 chemical components were detected. After fingerprint analysis, 13 common peaks were identified. The fingerprint similarity of 15 batches of samples ranged from 0.860 to 1.000. CPR analysis was able to categorically classify 15 batches of DJZD into two groups. And gingerenone A, methyl-6-gingerdiol, 6-gingerol, and hydroxy-β-sanshool contributed to their grouping. Twelve common components interact with the therapeutic targets for treating POI. In addition, the mechanism of this prescription for treating POI may be related to the jurisdiction of the neurological system, the immunological system, and the inflammatory response.

CONCLUSIONS

This integrated approach can accurately assess and forecast the quality of DJZD, presume the Q-Markers of DJZD for POI, and lay the foundation for studying the theoretical underpinnings and exploring the mechanism of DJZD in the treatment of POI.

Inhibition of the NF-κB and mTOR targets by urolithin A attenuates D-galactose-induced aging in mice

Urolithin A (Uro-A), an intestinal microbiota metabolite of ellagitannin, has anti-aging properties. Through the direct intake of ellagitannin (or ellagic acid) and strains capable of producing Uro-A, the transformation of Uro-A in vivo is a potential method to develop anti-aging preparations. Therefore, this study aimed to investigate the dose-response relationship between the colonic infusion of Uro-A and its anti-aging effects. Results indicated that Uro-A exhibited a dose-dependent anti-aging effect in the colon, and the minimum effective dose might be 3.0 mg kg-1 day-1. The main manifestations were that, compared with the model group, 3.0 mg kg-1 day-1 and 15.0 mg kg-1 day-1 of Uro-A can increase forelimb grip strength by 11.87% and 16.72%, respectively, and increase the discrimination index by 92.14% and 238.11%, respectively. Both doses effectively inhibited the D-galactose-induced increase in oxidative stress levels in the body, muscle atrophy, and neuronal apoptosis. Additionally, Uro-A released through the colon could alleviate D-galactose-induced aging in mice by inhibiting NF-κB and mTOR targets, providing significant protection for motor and cognitive functions. These findings provide a theoretical basis for future application and development of ellagitannin (or ellagic acid) in combination with strains capable of producing Uro-A.

Polyphenols in edible herbal medicine: targeting gut-brain interactions in depression-associated neuroinflammation

Supplementing with edible herbal medicine is an important strategy because of its role in nutrition. Many polyphenols, which are universal components in edible herbal medicines, have low bioavailability. Therefore, gut microbiota is a key determinant of polyphenol bioactivity. Polyphenols can alter the abundance of flora associated with neuroinflammation by reversing intestinal microbiota dysbiosis. Intestinal flora-mediated chemical modification of polyphenols can result in their conversion into active secondary metabolites. The current review summarizes the main edible medicines used in anti-depression and details the interactions between polyphenols and gut microbiota; in addition, it provides insights into the mechanisms underlying the possible suppression of neuroinflammation associated with depression, by polyphenols in edible herbal medicine. A better understanding of polyphenols with bioactivities that are crucial in edible herbal medicine may facilitate their use in the prevention and treatment of neuroinflammation associated with depression.

Urolithins: A Prospective Alternative against Brain Aging

The impact of host-microbiome interactions on cognitive health and disease has received increasing attention. Microbial-derived metabolites produced in the gut are one of crucial mechanisms of the gut-brain axis interaction, showing attractive perspectives. Urolithins (Uros) are gut microbial-derived metabolites of ellagitannins and ellagic acid, whose biotransformation varies considerably between individuals and decreases greatly with age. Recently, accumulating evidence has suggested that Uros may have specific advantages in preventing brain aging including favorable blood-brain barrier permeability, selective brain distribution, and increasingly supporting data from preclinical and clinical studies. However, the usability of Uros in diagnosis, prevention, and treatment of neurodegenerative diseases remains elusive. In this review, we aim to present the comprehensive achievements of Uros in age-related brain dysfunctions and neurodegenerative diseases and discuss their prospects and knowledge gaps as functional food, drugs, or biomarkers against brain aging.

Therapeutic targeting of Ras/Raf/MAPK pathway by natural products: A systematic and mechanistic approach for neurodegeneration

BACKGROUND

Multiple dysregulated pathways are behind the pathogenesis of neurodegenerative diseases (NDDs); however, the crucial targets are still unknown. Oxidative stress, apoptosis, autophagy, and inflammation are the most dominant pathways that strongly influence neurodegeneration. In this way, targeting the Ras/Raf/mitogen-activated protein kinases (MAPKs) pathway appears to be a developing strategy for combating NDDs like Parkinson's disease, Alzheimer's disease, stroke, aging, and other NDDs. Accordingly, plant secondary metabolites have shown promising potentials for the simultaneous modulation of the Ras/Raf/MAPKs pathway and play an essential role in NDDs. MAPKs include p38 MAPK, extracellular signal-regulated kinase 1/2 (ERK 1/2), and c-Jun N-terminal kinase (JNK), which are important molecular players in neurodegeneration. Ras/Raf, which is located the upstream of MAPK pathway influences the initiation and progression of neurodegeneration and is regulated by natural products.

PURPOSE

Thus, the present study aimed to investigate the neuroprotective roles of plant- and marine-derived secondary metabolites against several NDDs through the modulation of the Ras/Raf/MAPK signaling pathway.

STUDY DESIGN AND METHODS

A systematic and comprehensive review was performed to highlight the modulatory roles of natural products on the Ras/Raf/MAPK signaling pathway in NDDs, according to the PRISMA guideline, using scholarly electronic databases, including PubMed, Scopus, and Web of Sciences. Associated reference lists were also searched for the literature review.

RESULTS

From a total of 1495 results, finally 107 articles were included in the present study. The results show that several natural compounds such as alkaloid, phenolic, terpenoids, and nanoformulation were shown to have modulatory effects on the Ras/Raf/MAPKs pathway.

CONCLUSION

Natural products are promising multi-targeted agents with on NDDs through Ras/Raf/MAPKs pathway. Nevertheless, additional and complementary studies are necessary to check its efficacy and potential side effects.

Effects of Natural Product-Derived Compounds on Inflammatory Pain via Regulation of Microglial Activation

Inflammatory pain is a type of pain caused by tissue damage associated with inflammation and is characterized by hypersensitivity to pain and neuroinflammation in the spinal cord. Neuroinflammation is significantly increased by various neurotransmitters and cytokines that are expressed in activated primary afferent neurons, and it plays a pivotal role in the development of inflammatory pain. The activation of microglia and elevated levels of pro-inflammatory cytokines are the hallmark features of neuroinflammation. During the development of neuroinflammation, various intracellular signaling pathways are activated or inhibited in microglia, leading to the regulation of inflammatory proteins and cytokines. Numerous attempts have been conducted to alleviate inflammatory pain by inhibiting microglial activation. Natural products and their compounds have gained attention as potential candidates for suppressing inflammatory pain due to verified safety through centuries of use. Many studies have also shown that natural product-derived compounds have the potential to suppress microglial activation and alleviate inflammatory pain. Herein, we review the literature on inflammatory mediators and intracellular signaling involved in microglial activation in inflammatory pain, as well as natural product-derived compounds that have been found to suppress microglial activation. This review suggests that natural product-derived compounds have the potential to alleviate inflammatory pain through the suppression of microglial activation.

Pharmacotherapeutic potential of walnut (Juglans spp.) in age-related neurological disorders

Global and regional trends of population aging spotlight major public health concerns. As one of the most common adverse prognostic factors, advanced age is associated with a remarkable incidence risk of many non-communicable diseases, affecting major organ systems of the human body. Age-dependent factors and molecular processes can change the nervous system's normal function and lead to neurodegenerative disorders. Oxidative stress results from of a shift toward reactive oxygen species (ROS) production in the equilibrium between ROS generation and the antioxidant defense system. Oxidative stress and neuroinflammation caused by Amyloid-ß protein deposition in the human brain are the most likely pathogenesis of Alzheimer's disease (AD). Walnut extracts could reduce Amyloid-ß fibrillation and aggregation, indicating their beneficial effects on memory and cognition. Walnut can also improve movement disabilities in Parkinson's disease due to their antioxidant and neuroprotective effect by reducing ROS and nitric oxide (NO) generation and suppressing oxidative stress. It is noteworthy that Walnut compounds have potential antiproliferative effects on Glioblastoma (the most aggressive primary cerebral neoplasm). This effective therapeutic agent can stimulate apoptosis of glioma cells in response to oxidative stress, concurrent with preventing angiogenesis and migration of tumor cells, improving the quality of life and life expectancy of patients with glioblastoma. Antioxidant Phenolic compounds of the Walnut kernel could explain the significant anti-convulsion ability of Walnut to provide good prevention and treatment for epileptic seizures. Moreover, the anti-inflammatory effect of Walnut oil could be beneficial in treating multiple sclerosis. In this study, we review the pharmaceutical properties of Walnut in age-related neurological disorders.

Norbergenin prevents LPS-induced inflammatory responses in macrophages through inhibiting NFκB, MAPK and STAT3 activation and blocking metabolic reprogramming

Inflammation is thought to be a key cause of many chronic diseases and cancer. However, current therapeutic agents to control inflammation have limited long-term use potential due to various side-effects. This study aimed to examine the preventive effects of norbergenin, a constituent of traditional anti-inflammatory recipes, on LPS-induced proinflammatory signaling in macrophages and elucidate the underlying mechanisms by integrative metabolomics and shotgun label-free quantitative proteomics platforms. Using high-resolution mass spectrometry, we identified and quantified nearly 3000 proteins across all samples in each dataset. To interpret these datasets, we exploited the differentially expressed proteins and conducted statistical analyses. Accordingly, we found that LPS-induced production of NO, IL1β, TNFα, IL6 and iNOS in macrophages was alleviated by norbergenin via suppressed activation of TLR2 mediated NFκB, MAPKs and STAT3 signaling pathways. In addition, norbergenin was capable of overcoming LPS-triggered metabolic reprogramming in macrophages and restrained the facilitated glycolysis, promoted OXPHOS, and restored the aberrant metabolites within the TCA cycle. This is linked to its modulation of metabolic enzymes to support its anti-inflammatory activity. Thus, our results uncover that norbergenin regulates inflammatory signaling cascades and metabolic reprogramming in LPS stimulated macrophages to exert its anti-inflammatory potential.

Relationship between Dietary Polyphenols and Gut Microbiota: New Clues to Improve Cognitive Disorders, Mood Disorders and Circadian Rhythms

Cognitive, mood and sleep disorders are common and intractable disorders of the central nervous system, causing great inconvenience to the lives of those affected. The gut-brain axis plays a vital role in studying neurological disorders such as neurodegenerative diseases by acting as a channel for a bidirectional information exchange between the gut microbiota and the nervous system. Dietary polyphenols have received widespread attention because of their excellent biological activity and their wide range of sources, structural diversity and low toxicity. Dietary intervention through the increased intake of dietary polyphenols is an emerging strategy for improving circadian rhythms and treating metabolic disorders. Dietary polyphenols have been shown to play an essential role in regulating intestinal flora, mainly by maintaining the balance of the intestinal flora and enhancing host immunity, thereby suppressing neurodegenerative pathologies. This paper reviewed the bidirectional interactions between the gut microbiota and the brain and their effects on the central nervous system, focusing on dietary polyphenols that regulate circadian rhythms and maintain the health of the central nervous system through the gut-brain axis.

Natural products targeting cellular processes common in Parkinson's disease and multiple sclerosis

The hallmarks of Parkinson's disease (PD) include the loss of dopaminergic neurons and formation of Lewy bodies, whereas multiple sclerosis (MS) is an autoimmune disorder with damaged myelin sheaths and axonal loss. Despite their distinct etiologies, mounting evidence in recent years suggests that neuroinflammation, oxidative stress, and infiltration of the blood-brain barrier (BBB) all play crucial roles in both diseases. It is also recognized that therapeutic advances against one neurodegenerative disorder are likely useful in targeting the other. As current drugs in clinical settings exhibit low efficacy and toxic side effects with long-term usages, the use of natural products (NPs) as treatment modalities has attracted growing attention. This mini-review summarizes the applications of natural compounds to targeting diverse cellular processes inherent in PD and MS, with the emphasis placed on their neuroprotective and immune-regulating potentials in cellular and animal models. By reviewing the many similarities between PD and MS and NPs according to their functions, it becomes evident that some NPs studied for one disease are likely repurposable for the other. A review from this perspective can provide insights into the search for and utilization of NPs in treating the similar cellular processes common in major neurodegenerative diseases.

The Potential of Flavonoids and Flavonoid Metabolites in the Treatment of Neurodegenerative Pathology in Disorders of Cognitive Decline

Flavonoids are a biodiverse family of dietary compounds that have antioxidant, anti-inflammatory, antiviral, and antibacterial cell protective profiles. They have received considerable attention as potential therapeutic agents in biomedicine and have been widely used in traditional complimentary medicine for generations. Such complimentary medical herbal formulations are extremely complex mixtures of many pharmacologically active compounds that provide a therapeutic outcome through a network pharmacological effects of considerable complexity. Methods are emerging to determine the active components used in complimentary medicine and their therapeutic targets and to decipher the complexities of how network pharmacology provides such therapeutic effects. The gut microbiome has important roles to play in the generation of bioactive flavonoid metabolites retaining or exceeding the antioxidative and anti-inflammatory properties of the intact flavonoid and, in some cases, new antitumor and antineurodegenerative bioactivities. Certain food items have been identified with high prebiotic profiles suggesting that neutraceutical supplementation may be beneficially employed to preserve a healthy population of bacterial symbiont species and minimize the establishment of harmful pathogenic organisms. Gut health is an important consideration effecting the overall health and wellbeing of linked organ systems. Bioconversion of dietary flavonoid components in the gut generates therapeutic metabolites that can also be transported by the vagus nerve and systemic circulation to brain cell populations to exert a beneficial effect. This is particularly important in a number of neurological disorders (autism, bipolar disorder, AD, PD) characterized by effects on moods, resulting in depression and anxiety, impaired motor function, and long-term cognitive decline. Native flavonoids have many beneficial properties in the alleviation of inflammation in tissues, however, concerns have been raised that therapeutic levels of flavonoids may not be achieved, thus allowing them to display optimal therapeutic effects. Dietary manipulation and vagal stimulation have both yielded beneficial responses in the treatment of autism spectrum disorders, depression, and anxiety, establishing the vagal nerve as a route of communication in the gut-brain axis with established roles in disease intervention. While a number of native flavonoids are beneficial in the treatment of neurological disorders and are known to penetrate the blood–brain barrier, microbiome-generated flavonoid metabolites (e.g., protocatechuic acid, urolithins, γ-valerolactones), which retain the antioxidant and anti-inflammatory potency of the native flavonoid in addition to bioactive properties that promote mitochondrial health and cerebrovascular microcapillary function, should also be considered as potential biotherapeutic agents. Studies are warranted to experimentally examine the efficacy of flavonoid metabolites directly, as they emerge as novel therapeutic options.

Co-transplantation of novel Nano-SDF scaffold with human neural stem cells attenuates inflammatory responses and apoptosis in traumatic brain injury

Traumatic brain injury (TBI) causes long-term disability and mortality worldwide. The prime pathological players in TBI are neuroinflammation and apoptosis. These pathological changes lead to a limited capacity of regeneration after TBI. To alleviate inflammatory responses and apoptosis triggered by TBI, developing bioactive scaffolds conjoined with stem cells is a decisive approach in neural tissue engineering. The aim of this study was to fabricate a novel nano-scaffold made of RADA-16 with a bioactive motif of stromal cell-derived factor-1 α (SDF-1α) and evaluate its effects with stem cell transplantation on inflammatory pathways, reactive gliosis, and apoptosis after TBI. Co-transplantation of Nano-SDF and human neural stem cells (hNSCs) derived from fetus brain in adult rats subjected to TBI led to the improvement of motor activitycompared with the control group. The treated animals with hNSCs + Nano-SDF had a significantly lower expression of toll-like receptor 4 and nuclear factor-kappa B at the injury site than the control animals. A significant reduction in the number of reactive astrocytes was also observed in rats that received hNSCs + Nano-SDF compared with the vehicle and Nano-SDF groups. Furthermore, the TUNEL assay indicated a significant reduction in TUNEL positive cells in the hNSCs + Nano-SDF group compared with the TBI, vehicle, and Nano-SDF groups. These data demonstrated co-transplantation of hNSCs with Nano-SDF can reduce inflammatory responses and cell death after TBI via creating a more supportive microenvironment. Further research is required to establish the therapeutic efficacy of Nano-SDF with stem cells for TBI.

Preventive and Therapeutic Effects of Punica granatum L. Polyphenols in Neurological Conditions

Pomegranate (Punica granatum L.) is a polyphenol-rich food and medicinal plant containing flavonols, anthocyanins, and tannins. Ellagitannins (ETs) are the most abundant polyphenols in pomegranate. A growing body of research shows that polyphenol-rich pomegranate extracts and their metabolites target multiple types of brain cell and support their redox balance, proliferation and survival, as well as cell signaling. Independent studies have demonstrated that the significant neuroprotective effects of ETs are mediated by their antioxidant and anti-inflammatory effects, their chelating properties, by their ability to activate various signaling pathways, as well as the ability to influence mitochondrial damage, thus regulating autophagy, apoptosis and neurotransmitter signaling. The multitude of in vitro and in vivo studies summarized in the present review suggest that pomegranate polyphenols act on both neuronal and glial cells directly, and also affect blood-brain barrier function, restoring redox balance in the blood and brain and increasing blood flow to the brain.

Chemical constituents of industrial hemp roots and their anti-inflammatory activities

OBJECTIVE

Although the chemical constituents of the aerial parts of Cannabis have been extensively studied, phytochemicals of Cannabis roots are not well characterized. Herein, we investigated the chemical constituents of industrial hemp (Cannabis sativa L.) roots and evaluated the anti-inflammatory activities of phytochemicals isolated from the hemp roots extract.

METHODS

An ethyl acetate extract of hemp roots was subjected to a combination of chromatographic columns to isolate phytochemicals. The chemical structures of the isolates were elucidated based on spectroscopic analyses (by nuclear magnetic resonance and mass spectrometry). The anti-inflammatory effects of phytochemicals from hemp roots were evaluated in an anti-inflammasome assay using human monocyte THP-1 cells.

RESULTS

Phytochemical investigation of hemp roots extract led to the identification of 32 structurally diverse compounds including six cannabinoids (1-6), three phytosterols (26-28), four triterpenoids (22-25), five lignans (17-21), and 10 hydroxyl contained compounds (7-16), three fatty acids (29-31), and an unsaturated chain hydrocarbon (32). Compounds 14-21, 23, 27, and 32 were identified from the Cannabis species for the first time. Cannabinoids (1-5) reduced the level of cytokine tumor necrosis-alpha (by 38.2, 58.4, 47.7, 52.2, and 56.1%, respectively) and 2 and 5 also decreased the interleukin-1β production (by 42.2 and 92.4%, respectively) in a cell-based inflammasome model. In addition, non-cannabinoids including 11, 13, 20, 25, 29, and 32 also showed selective inhibition of interleukin-1β production (by 23.7, 22.5, 25.6, 78.0, 24.1, 46.6, and 25.4%, respectively) in THP-1 cells.

CONCLUSION

The phytochemical constituent of a hemp roots extract was characterized and compounds from hemp roots exerted promising anti-inflammatory effects.

The Impact of Ellagitannins and Their Metabolites through Gut Microbiome on the Gut Health and Brain Wellness within the Gut-Brain Axis

Ellagitannins (ETs) are a large group of bioactive compounds found in plant-source foods, such as pomegranates, berries, and nuts. The consumption of ETs has often been associated with positive effects on many pathologies, including cardiovascular diseases, neurodegenerative syndromes, and cancer. Although multiple biological activities (antioxidant, anti-inflammatory, chemopreventive) have been discussed for ETs, their limited bioavailability prevents reaching significant concentrations in systemic circulation. Instead, urolithins, ET gut microbiota-derived metabolites, are better absorbed and could be the bioactive molecules responsible for the antioxidant and anti-inflammatory activities or anti-tumor cell progression. In this review, we examined the dietary sources, metabolism, and bioavailability of ETs, and analyzed the last recent findings on ETs, ellagic acid, and urolithins, their intestinal and brain activities, the potential mechanisms of action, and the connection between the ET microbiota metabolism and the consequences detected on the gut-brain axis. The current in vitro, in vivo, and clinical studies indicate that ET-rich foods, individual gut microbiomes, or urolithin types could modulate signaling pathways and promote beneficial health effects. A better understanding of the role of these metabolites in disease pathogenesis may assist in the prevention or treatment of pathologies targeting the gut-brain axis.

Design, synthesis, and biological evaluation of urolithin derivatives as potential phosphodiesterase II inhibitors

Urolithins are the gut microbiota metabolites of ellagitannins which are found in natural plants such as pomegranate, strawberry, and raspberry, and in nuts. Recently, several reports have clarified the underlying mechanism of urolithins in central nervous system inflammation. Therefore, urolithins have become potential therapeutic drug candidate molecules for central nervous system diseases. Derivatives 1–1d, 1–1f, 3–2a, and 3–2b of urolithin A, urolithin B, and methoxyurolithin A were found to have had significant inhibitory activity against phosphodiesterase II with IC50 values of 35.42, 39.96, 25.58, and 13.84 μM, respectively. Herein, we report the design and synthesis of urolithin derivatives along with a biological evaluation of their activity against phosphodiesterase II.

The Effects of Urolithin B and Auraptene on Quinolinic Acid-induced Toxicity in the SH-SY5Y Neuroblastoma Cell Line

The pathological accumulation of quinolinic acid (QA) is often associated with neuritis and neuronal cell death in several neurodegenerative diseases, through the overproduction of free radicals. Urolithin B and auraptene have been reported to exert potent antioxidant effects - however, little is known about the protective effects of these compounds against QA-induced neurotoxicity. Therefore, this study aimed to explore the in vitro protective effects of urolithin B and auraptene against QA-induced neurotoxicity in the SH-SY5Y neuroblastoma cell line. The MTT assay was used to evaluate cell viability, and flow cytometry was carried out to evaluate effects on the cell cycle and apoptosis. The intracellular levels of reactive oxygen species (ROS) were also determined. Our findings showed that auraptene at non-toxic concentrations had no protective effect on QA-induced toxicity. However, urolithin B at concentrations of 0.6 μM and 2.5 μM enhanced the viability of cells treated with QA. Moreover, while the percentage of apoptotic cells (i.e. in the sub-G1 phase) was shown to significantly increase after QA treatment, pre-treatment with urolithin B reduced the number of these apoptotic cells. Furthermore, urolithin B, as an antioxidant, also significantly reduced QA-induced ROS production. Our findings suggest that urolithin B may possess potent antioxidant and neuroprotective effects against QA-induced neurotoxicity that merit further investigation.

Effects of Apamin on MPP+-Induced Calcium Overload and Neurotoxicity by Targeting CaMKII/ERK/p65/STAT3 Signaling Pathways in Dopaminergic Neuronal Cells

Parkinson's disease (PD), a neurodegenerative disorder, is characterized by the loss of dopaminergic (DA) neurons. The pathogenesis of PD is associated with several factors including oxidative stress, inflammation, and mitochondrial dysfunction. Ca²⁺ signaling plays a vital role in neuronal signaling and altered Ca²⁺ homeostasis has been implicated in many neuronal diseases including PD. Recently, we reported that apamin (APM), a selective antagonist of the small-conductivity Ca²⁺-activated K⁺ (SK) channel, suppresses neuroinflammatory response. However, the mechanism(s) underlying the vulnerability of DA neurons were not fully understood. In this study, we investigated whether APM affected 1-methyl-4-phenyl pyridinium (MPP⁺)-mediated neurotoxicity in SH-SY5Y cells and rat embryo primary mesencephalic neurons. We found that APM decreased Ca²⁺ overload arising from MPP⁺-induced neurotoxicity response through downregulating the level of CaMKII, phosphorylation of ERK, and translocation of nuclear factor NFκB/signal transducer and activator of transcription (STAT)3. Furthermore, we showed that the correlation of MPP⁺-mediated Ca²⁺ overload and ERK/NFκB/STAT3 in the neurotoxicity responses, and dopaminergic neuronal cells loss, was verified through inhibitors. Our findings showed that APM might prevent loss of DA neurons via inhibition of Ca²⁺-overload-mediated signaling pathway and provide insights regarding the potential use of APM in treating neurodegenerative diseases.

Manipulation of the diet-microbiota-brain axis in Alzheimer's disease

Several studies investigating the pathogenesis of Alzheimer's disease have identified various interdependent constituents contributing to the exacerbation of the disease, including Aβ plaque formation, tau protein hyperphosphorylation, neurofibrillary tangle accumulation, glial inflammation, and the eventual loss of proper neural plasticity. Recently, using various models and human patients, another key factor has been established as an influential determinant in brain homeostasis: the gut-brain axis. The implications of a rapidly aging population and the absence of a definitive cure for Alzheimer's disease have prompted a search for non-pharmaceutical tools, of which gut-modulatory therapies targeting the gut-brain axis have shown promise. Yet multiple recent studies examining changes in human gut flora in response to various probiotics and environmental factors are limited and difficult to generalize; whether the state of the gut microbiota in Alzheimer's disease is a cause of the disease, a result of the disease, or both through numerous feedback loops in the gut-brain axis, remains unclear. However, preliminary findings of longitudinal studies conducted over the past decades have highlighted dietary interventions, especially Mediterranean diets, as preventative measures for Alzheimer's disease by reversing neuroinflammation, modifying the intestinal and blood-brain barrier (BBB), and addressing gut dysbiosis. Conversely, the consumption of Western diets intensifies the progression of Alzheimer's disease through genetic alterations, impaired barrier function, and chronic inflammation. This review aims to support the growing body of experimental and clinical data highlighting specific probiotic strains and particular dietary components in preventing Alzheimer's disease via the gut-brain axis.

PCL NGCs integrated with urolithin-A-loaded hydrogels for nerve regeneration

Inflammation and oxidative stress are among the leading causes of poor prognosis after peripheral nerve injury (PNI). Urolithin-A (UA), an intermediate product produced by the catabolism of ellagitannins in the gastrointestinal tract, has anti-inflammatory, antioxidant, and immunomodulatory properties for inflammation, oxidative damage, and aging-related diseases. Hence, we prepared UA-loaded hydrogels and embedded them in the lumen of PCL nerve guide conduits (NGCs). The hydrogels continuously released appropriate doses of UA into the microenvironment. Based on in vitro studies, UA facilitates cell proliferation and reduces oxidative damage. Besides, the experimental evaluation revealed good biocompatibility of the materials involved. We implanted NGCs into rat models to bridge the sciatic nerve defects in an in vivo study. The sciatic functional index of the PCL/collagen/UA group was comparable to that of the autograft group. Additionally, the consequences of electrophysiological, gastrocnemius muscle and nerve histology assessment of the PCL/collagen/UA group were better than those in the PCL and PCL/collagen groups and close to those in the autograft group. In this study, UA sustained release via the PCL/collagen/UA NGC was found to be an effective alternative treatment for PNI, validating our hypothesis that UA could promote regeneration of nerve tissue.

Urolithins: a Comprehensive Update on their Metabolism, Bioactivity, and Associated Gut Microbiota

Urolithins, metabolites produced by the gut microbiota from the polyphenols ellagitannins and ellagic acid, are discovered by the research group in humans almost 20 years ago. Pioneering research suggests urolithins as pleiotropic bioactive contributors to explain the health benefits after consuming ellagitannin-rich sources (pomegranates, walnuts, strawberries, etc.). Here, this study comprehensively updates the knowledge on urolithins, emphasizing the review of the literature published during the last 5 years. To date, 13 urolithins and their corresponding conjugated metabolites (glucuronides, sulfates, etc.) have been described and, depending on the urolithin, detected in different human fluids and tissues (urine, blood, feces, breastmilk, prostate, colon, and breast tissues). There has been a substantial advance in the research on microorganisms involved in urolithin production, along with the compositional and functional characterization of the gut microbiota associated with urolithins metabolism that gives rise to the so-called urolithin metabotypes (UM-A, UM-B, and UM-0), relevant in human health. The design of in vitro studies using physiologically relevant assay conditions (molecular forms and concentrations) is still a pending subject, making some reported urolithin activities questionable. In contrast, remarkable progress has been made in the research on the safety, bioactivity, and associated mechanisms of urolithin A, including the first human interventions.

Inhibition of glioblastoma proliferation, invasion, and migration by Urolithin B through inducing G0/G1 arrest and targeting MMP-2/-9 expression and activity

One kind of brain cancer with a dismal prognosis is called glioblastoma multiforme (GBM) due to its high growth rate and widespread tumor cell invasion into various areas of the brain. To improve therapeutic approaches, the objective of this research investigates the cytotoxic, anti-metastatic, and apoptotic effect of urolithin-B (UB) as a bioactive metabolite of ellagitannins (ETs) on GBM U87 cells. The malignant GBM cell line (U87) was examined for apoptosis rate, cell cycle analysis, cell viability, mRNA expressions of several apoptotic and metastasis-associated genes, production of reactive oxygen species (ROS), MMP-2, and MMP-9 activity and protein expression, and migration ability. The findings revealed that UB decreased U87 GBM viability in a dose-dependent manner and NIH/3T3 normal cells with the IC₅₀ value of 30 and 55 μM after 24 h, respectively. UB also induces necrosis and G0/G1 cell cycle arrest in U87 cells. UB also increases ROS production and caused down-regulation of Bcl2 and up-regulation of Bax apoptotic genes. Additionally, treatment of UB reduced the migration of U87 cells. The protein levels, mRNA expression, and the MMP-2 and MMP-9 enzyme activities also decreased concentration-dependently. So, due to the non-toxic nature of UB and its ability to induce apoptosis and reduce the U87 GBM cell invasion and migration, after more research, it can be regarded as a promising new anti-GBM compound.

Modifiable Innate Biology within the Gut–Brain Axis for Alzheimer’s Disease

Alzheimer’s disease (AD) is a prototypical inflammation-associated loss of cognitive function, with approximately 90% of the AD burden associated with invading myeloid cells controlling the function of the resident microglia. This indicates that the immune microenvironment has a pivotal role in the pathogenesis of the disease. Multiple peripheral stimuli, conditioned by complex and varied interactions between signals that stem at the intestinal level and neuroimmune processes, are involved in the progression and severity of AD. Conceivably, the targeting of critical innate immune signals and cells is achievable, influencing immune and metabolic health within the gut–brain axis. Considerable progress has been made, modulating many different metabolic and immune alterations that can drive AD development. However, non-pharmacological strategies targeting immunometabolic processes affecting neuroinflammation in AD treatment remain general and, at this point, are applied to all patients regardless of disease features. Despite these possibilities, improved knowledge of the relative contribution of the different innate immune cells and molecules comprising the chronically inflamed brain network to AD pathogenesis, and elucidation of the network hierarchy, are needed for planning potent preventive and/or therapeutic interventions. Moreover, an integrative perspective addressing transdisciplinary fields can significantly contribute to molecular pathological epidemiology, improving the health and quality of life of AD patients. This review is intended to gather modifiable immunometabolic processes based on their importance in the prevention and management of AD.

Identification of ellagic acid and urolithins as natural inhibitors of Aβ25-35-induced neurotoxicity and the mechanism predication using network pharmacology analysis and molecular docking

Ellagic acid (EA) is a dietary polyphenol that widely exists in grapes, strawberries, and walnuts. It usually exerts multiple biological activities together with its in vivo metabolites called urolithins. EA and urolithins had been proposed as natural agents for applying on the early intervention of Alzheimer’s disease (AD). However, the neuroprotective effects of those small molecules have not been confirmed, and the action mechanism is not clear. Deposition of beta-amyloid (Aβ) protein is well documented as being involved in the initiation and pathological process of AD. In the present study, we investigated the attenuating effects of EA and several urolithins on Aβ_25–35-induced neuronal injury and its underlying molecular mechanism by constructing the in vitro AD cell model of PC12 cells and primary neurons. The results revealed that EA and urolithins especially the UM5 and UM6 exerted promising neuroprotective effects in improving the Aβ_25–35-induced cell damage and lactate dehydrogenase (LDH) leakage, reducing reactive oxygen species (ROS) production, inhibiting neuronal apoptosis, and promoting neurite outgrowth. These results provide new insights into the development of UM5 and UM6 as anti-AD candidates. A network pharmacology analysis combining molecular docking strategy was further adopted to predict the signaling pathway involved in the anti-AD action of EA and urolithins, and the activation of PI3K-Akt, as well as the inhibition of MAPK was found to be involved.

Health functions and related molecular mechanisms of ellagitannin-derived urolithins

Ellagitannins are vital bioactive polyphenols that are widely distributed in a variety of plant-based foods. The main metabolites of ellagitannins are urolithins, and current research suggests that urolithins provide a variety of health benefits. This review focused on the role of the gut bacteria in the conversion of ellagitannins to urolithins. Based on the results of in vitro and in vivo studies, the health benefits of urolithins, including antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-aging, cardiovascular protective, neuroprotective, kidney protective, and muscle mass protective effects, were thoroughly outlined, with a focus on their associated molecular mechanisms. Finally, we briefly commented on urolithins' safety. Overall, urolithins' diverse health benefits indicate the potential utilization of ellagitannins and urolithins in the creation of functional foods and nutraceuticals to treat and prevent some chronic diseases.

Punicalagin Protects against Diabetic Liver Injury by Upregulating Mitophagy and Antioxidant Enzyme Activities

Diabetic liver injury has received increasing attention as a serious complication of type 2 diabetes. Punicalagin (PU), a major component of pomegranate polyphenols, has various biological activities such as antioxidant, anti-inflammatory, and lipid metabolism regulation. In this study, we observed the protective effect of punicalagin on a high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic liver injury in mice and revealed the underlying mechanism. The results showed that fasting blood glucose (FBG), fasting serum insulin (FINS), and homeostasis model assessment for insulin resistance (HOMA-IR) in diabetic liver injury mice were significantly decreased after punicalagin intervention. Simultaneously, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), free fatty acids (FFA), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) in the serum and liver were significantly decreased, with reductions in fat lesions and inflammatory cells. Mitophagy is a selective autophagy that maintains a balance between the quality and quantity of intracellular mitochondria. Studies have shown that mitophagy is closely related to the occurrence and development of diabetic liver injury. In our study, the mitochondrial membrane potential (MMP) was significantly increased in mice with diabetic liver injury after punicalagin intervention; the protein expression of Pink1, Parkin, Bnip3, LC3b, P62, manganese superoxide dismutase (MnSOD), and catalase (CAT) was significantly increased in the liver; and the activities of MnSOD and CAT in the serum and liver were significantly increased, which is consistent with the results of in vitro experiments. In summary, our study provided evidence that punicalagin could reduce the level of oxidative stress in the liver by upregulating mitophagy and the activities of antioxidant enzymes, thus having a certain protective effect against diabetic liver injury.

Urolithin A inhibits enterovirus 71 replication and promotes autophagy and apoptosis of infected cells in vitro

Hand, foot, and mouth disease (HFMD) is a serious threat to the health of infants, and it can be caused by enterovirus 71 (EV71). The clinical symptoms are mostly self-limiting, but some infections develop into aseptic meningitis with poor prognosis and even death. In this study, urolithin A (UroA), an intestinal metabolite of ellagic acid, significantly inhibited the replication of EV71 in cells. Further evaluation showed that UroA was better than ribavirin in terms of its 50% cytopathic concentration (CC₅₀), 50% inhibitory concentration (IC₅₀), and selectivity index. Moreover, UroA inhibited the proliferation of EV71 by promoting autophagy and apoptosis of infected cells. Therefore, UroA is a candidate drug for the treatment of EV71 infection.

Urolithin B suppresses osteoclastogenesis via inhibiting RANKL-induced signalling pathways and attenuating ROS activities

Osteoporosis (OP) has severely affected human health, which is characterized by abnormal differentiation of osteoclasts. Urolithin B (UB), as a potential natural drug, has been reported to exhibit numerous biological activities including antioxidant and anti‐inflammatory but its effects on OP, especially on RANKL‐stimulated osteoclast formation and activation, are still understood. In our study, we have demonstrated for the first time that UB inhibits RANKL‐induced osteoclast differentiation and explored its potential mechanisms of action. The RAW264.7 cells were cultured and induced with RANKL followed by UB treatment. Then, the effects of UB on mature osteoclast differentiation were evaluated by counting tartrate‐resistant acid phosphatase (TRAP)‐positive multinucleated cells and F‐actin ring analysis. Moreover, the effects of UB on RANKL‐induced reactive oxygen species (ROS) were measured by 2′, 7′‐dichlorodihydrofluorescein diacetate (DCFH‐DA) staining. Further, we explored the potential mechanisms of these downregulation effects by performing Western blotting and quantitative RT‐PCR examination. We found that UB represses osteoclastogenesis, F‐actin belts formation, osteoclast‐specific gene expressions and ROS activity in a time‐ and concentration‐dependent manner. Mechanistically, UB attenuates intracellular ROS levels by upregulation of Nrf2 and other ROS scavenging enzymes activation. Furthermore, UB also inhibited RANKL‐induced NF‐κB, MAPK and Akt signalling pathway and suppressed expression of c‐Fos and nuclear factor of activated T cells 1 (NFATc1), which is the master transcription factor of osteoclast differentiation. Taken together, our findings confirm that UB is a polyphenolic compound that can be a potential therapeutic treatment for osteoclast‐related bone diseases such as osteoporosis.

Urolithins: potential biomarkers of gut dysbiosis and disease stage in Parkinson's patients

Gut microbiota alteration (gut dysbiosis) occurs during the onset and progression of Parkinson's disease. Gut dysbiosis biomarkers could be relevant to prodromal disease. Urolithins, anti-inflammatory metabolites produced from some dietary polyphenols by specific gut microbial ecologies (urolithin metabotypes), have been proposed as biomarkers of gut microbiota composition and functionality. However, this has not been explored in Parkinson's disease patients. The current study aimed to assess associations between urolithin metabotypes, gut dysbiosis and disease severity in Parkinson's disease patients. Participants (52 patients and 117 healthy controls) provided stool samples for microbiota sequencing and urine samples for urolithin profiling before and after consuming 30 g of walnuts for three days. Data on demographics, medication, disease duration and Hoehn and Yahr disease stage were collected. We observed a significant gradual increase of urolithin non-producers (metabotype-0) as the disease severity increased. The gut microbiome of metabotype-0 patients and patients with the greatest severity was characterized by a more altered bacterial composition, i.e., increased pro-inflammatory Enterobacteriaceae and reduced protective bacteria against autoimmune and inflammatory processes, including butyrate and urolithin-producing bacteria (Lachnospiraceae members and Gordonibacter). Besides, their microbiome was characterized by predictive functions of lipopolysaccharide biosynthesis and metabolism of glutathione, cysteine and methionine that could indirectly reflect the gut pro-inflammatory status. Urolithin detection in urine is a feasible, non-invasive and fast approach that can reflect gut microbiome dysbiosis and intestinal inflammation in Parkinson's disease patients. Our current study could provide novel strategies for improving diagnostics, and for preventing and treating disease progression in microbiota-based interventions.

New Monoterpene Acid and Gallic Acid Glucose Esters with Anti-Inflammatory Activity from Blue Gum (Eucalyptus globulus) Leaves

Blue gum (Eucalyptus globulus) is a widely used botanical in the cosmeceutical and food industries. Although blue gum leaves are known for abundant essential oils, their nonvolatile phytochemical constituents and bioactivities remain unclear. Herein, a phytochemical investigation of blue gum leaves led to the identification of eight new monoterpene acid and gallic acid glucose esters (1-4 and 14-17; glubosides A-H, respectively) and 12 known analogues (5-13 and 18-20). Their structures were determined based on extensive spectroscopic data analysis, chemical degradation, and chiral separation. Oleuropeic acid conjugated glucose esters (1-13, 15, 16, 18, and 20) are reported as epimeric mixtures. Compounds 7, 12, 14, 19, and 20 (at 30 μM) inhibited nitrite release in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compounds 7 and 14 (at 3-30 μM) also down-regulated proinflammatory biomarkers, including cytokines (TNF-α, IL-6, and IL-1β), protein expression (iNOS and COX-2), and transcription factor nuclear translocation (NF-κB) in LPS-stimulated RAW264.7 cells. This work highlights the anti-inflammatory potential of phytochemicals from blue gum leaves, which supports their further development as cosmeceutical and/or nutraceutical products.

Two new polypodane-type bicyclic triterpenoids from mastic

Pistacia lentiscus L. is an evergreen shrub belonging to the Anacardiaceae family, cultivated exclusively in the southern area of Chios Island. Mastic gum as a unique natural resin of the tree Pistacia lentiscus L. has been used extensively in functional foods and traditional medicine. The biological properties of Pistacia resins may be influenced by different chemical constituents. Herein the present work is aimed to further explore the diverse triterpenoids of mastic, and evaluate their anti-inflammatory activity. Two undescribed polypodane-type bicyclic triterpenoids were isolated from the Pistacia resins, their structures were elucidated using ultraviolet, infrared, high resolution electrospray ionization mass spectroscopy (HRESIMS), and nuclear magnetic resonance data. LPS-stimulated RAW264.7 macrophages were incubated with various concentrations of isolated compounds, and results showed that compounds 1 and 2 inhibited nitric oxide production in LPS-induced RAW264.7 cells with IC50 values of 28.1 and 32.6 µM, respectively.

Coptisine Alleviates Imiquimod-Induced Psoriasis-like Skin Lesions and Anxiety-like Behavior in Mice

Psoriasis is a common inflammatory skin disorder, which can be associated with psychological disorders, such as anxiety and depression. This study investigated the efficacy and the mechanism of action of a natural compound coptisine using imiquimod (IMQ)-induced psoriasis mice. Coptisine reduced the severity of psoriasis-like skin lesions, decreased epidermal hyperplasia and the levels of inflammatory cytokines TNF-α, IL-17, and IL-22. Furthermore, coptisine improved IMQ-induced anxiety in mice by increasing the number of entries and time in open arms in the elevated plus maze (EPM) test. Coptisine also lowered the levels of inflammatory cytokines TNF-α and IL-1β in the prefrontal cortex of psoriasis mice. HaCaT keratinocytes and BV2 microglial cells were used to investigate the effects of coptisine in vitro. In M5-treated HaCaT cells, coptisine decreased the production of IL-6, MIP-3α/CCL20, IP-10/CXCL10, and ICAM-1 and suppressed the NF-κB signaling pathway. In LPS-stimulated BV2 cells, coptisine reduced the secretion of TNF-α and IL-1β. These findings suggest that coptisine might be a potential candidate for psoriasis treatment by improving both disease severity and psychological comorbidities.

Urolithin A alleviates blood-brain barrier disruption and attenuates neuronal apoptosis following traumatic brain injury in mice

Urolithin A (UA) is a natural metabolite produced from polyphenolics in foods such as pomegranates, berries, and nuts. UA is neuroprotective against Parkinson's disease, Alzheimer's disease, and cerebral hemorrhage. However, its effect against traumatic brain injury remains unknown. In this study, we established adult C57BL/6J mouse models of traumatic brain injury by controlled cortical impact and then intraperitoneally administered UA. We found that UA greatly reduced brain edema; increased the expression of tight junction proteins in injured cortex; increased the immunopositivity of two neuronal autophagy markers, microtubule-associated protein 1A/B light chain 3A/B (LC3) and p62; downregulated protein kinase B (Akt) and mammalian target of rapamycin (mTOR), two regulators of the phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR signaling pathway; decreased the phosphorylation levels of inhibitor of NFκB (IκB) kinase alpha (IKKα) and nuclear factor kappa B (NFκB), two regulators of the neuroinflammation-related Akt/IKK/NFκB signaling pathway; reduced blood-brain barrier permeability and neuronal apoptosis in injured cortex; and improved mouse neurological function. These findings suggest that UA may be a candidate drug for the treatment of traumatic brain injury, and its neuroprotective effects may be mediated by inhibition of the PI3K/Akt/mTOR and Akt/IKK/NFκB signaling pathways, thus reducing neuroinflammation and enhancing autophagy.