Osthole, a natural coumarin improves cognitive impairments and BBB dysfunction after transient global brain ischemia in C57 BL/6J mice: involvement of Nrf2 pathway

Clausena harmandiana root extract ameliorates Aβ1-42 induced cognitive deficits, oxidative stress, and apoptosis in rats

BACKGROUND

Clausena harmandiana (CH), commonly known as song fa dong, was a medicinal plant traditionally used to treat illnesses and as a health tonic. CH root extract (CHRE) exhibited various bioactivities, including neuroprotective, antioxidant, antimicrobial, antifungal, anti-inflammatory, and anti-cancer effects. However, CHRE data on neuroprotective in AD-like animal models were still scarce.

OBJECTIVES

This study aimed to investigate the effects of CHRE on Aβ1-42-induced cognitive deficits, free radical damage, and neuronal death in rats.

METHODS

Forty-eight adult male Sprague-Dawley rats (250-300 g) were classified as sham control (SC), V+Aβ, Vit C+Aβ, CHRE125+Aβ, CHRE250+Aβ, and CHRE500+Aβ (n = 8 in each group). Animals were orally administered with 0.5% sodium carboxymethylcellulose, vitamin C (200 mg/kg BW), or CHRE (125, 250, and 500 mg/kg BW) and were untreated for 35 days. On day 21, all treated rats were injected with 1 µl of aggregated Aβ1-42 (1 µg/µl) into the lateral ventricles, bilaterally, whereas untreated rats were injected with sterilized normal saline (NS). The Morris water maze test estimated the rat's learning and memory one week later. At the end of the treatment, all rats were sacrificed, and their brains were removed and divided into two hemispheres. On the left, morphological changes and neuronal density were observed in hippocampal CA1 and CA3 regions. While, on the right, changes in free radical damage markers (SOD, CAT, GPx, MDA, and Nrf2) and protein expression of active caspase-3 were evaluated in the hippocampus.

RESULTS

Pretreatment with CHRE at all doses could alleviate spatial learning and memory defects. CHRE also improved morphological changes and a decrease in neuronal density in CA1 and CA3 regions. Additionally, CHRE significantly increased the activities of antioxidant enzymes (SOD, CAT, GPx) and Nrf2 expression. This was coupled with significantly decreased MDA levels and active caspase-3 expression in the hippocampus of Aβ1-42-induced rats, which was similar to vitamin C exposure.

CONCLUSIONS

Our findings suggested that CHRE ameliorated cognitive deficits and exhibited neuroprotective effects by reducing free radical damage and mitigating neuronal abnormality and neuronal death.

Oral administration of osthole mitigates maladaptive behaviors through PPARα activation in mice subjected to repeated social defeat stress

Psychological stress induces neuroinflammatory responses, which are associated with the pathogenesis of various psychiatric disorders, such as posttraumatic stress disorder and anxiety. Osthole-a natural coumarin isolated from the seeds of the Chinese herb Cnidium monnieri-exerts anti-inflammatory and antioxidative effects on the central nervous system. However, the therapeutic benefits of osthole against psychiatric disorders remain largely unknown. We previously demonstrated that mice subjected to repeated social defeat stress (RSDS) in the presence of aggressor mice exhibited symptoms of posttraumatic stress disorder, such as social avoidance and anxiety-like behaviors. In this study, we investigated the therapeutic effects of osthole and the underlying molecular mechanisms. Osthole exerted therapeutic effects on cognitive behaviors, mitigating anxiety-like behaviors and social avoidance in a mouse model of RSDS. The anti-inflammatory response induced by the oral administration of osthole was strengthened through the upregulation of heme oxygenase-1 expression. The expression of PPARα was inhibited in mice subjected to RSDS. Nonetheless, osthole treatment reversed the inhibition of PPARα expression. We identified a positive correlation between heme oxygenase-1 expression and PPARα expression in osthole-treated mice. In conclusion, osthole has potential as a Chinese herbal medicine for anxiety disorders. When designing novel drugs for psychiatric disorders, researchers should consider targeting the activation of PPARα.

Coumarin-Synthetic Methodologies, Pharmacology, and Application as Natural Fluorophore

Coumarins are secondary metabolites made up of benzene and α-pyrone rings fused together that can potentially treat various ailments, including cancer, metabolic, and degenerative disorders. Coumarins are a diverse category of both naturally occurring as well as synthesized compounds with numerous biological and therapeutic properties. Coumarins as fluorophores play a key role in fluorescent labeling of biomolecules, metal ion detection, microenvironment polarity detection, and pH detection. This review provides a detailed insight into the characteristics of coumarins as well as their biosynthesis in plants and metabolic pathways. Various synthetic strategies for coumarin core involving both conventional and green methods have been discussed comparing advantages and disadvantages of each method. Conventional methods discussed are Pechmann, Knoevenagel, Perkin, Wittig, Kostanecki, Buchwald-Hartwig, and metal-induced coupling reactions such as Heck and Suzuki, as well as green approaches involving microwave or ultrasound energy. Various pharmacological applications of coumarin derivatives are discussed in detail. The structural features and conditions responsible for influencing the fluorescence of coumarin core are also elaborated.

3-Acetyl coumarin alleviate neuroinflammatory responses and oxidative stress in aluminum chloride-induced Alzheimer's disease rat model

Alzheimer's disease (AD) is a neurodegenerative disorder that impairs mental ability and interrupts cognitive function. Heavy metal exposure like aluminum chloride is associated with neurotoxicity linked to neuro-inflammation, oxidative stress, accumulation of amyloid plaques, phosphorylation of tau proteins associated with AD like symptoms. The objective of the present investigation was to assess the effect 3-acetyl coumarin (3AC) in a rat model of AD. Preliminary screening was performed with SWISS ADME to check for the bioavailability of 3-AC and likeness score which proved favorable. 3-AC docked against Caspase 3, NF-κβ and tau protein kinase I exhibited good binding energies. Male rats were divided into six groups (n = 5). AlCl3 (100 mg/kg BW) was administered for 28 days before starting treatment to induce AD. Normal control rats received vehicle. Treatment groups received 10, 20 and 30 mg/kg 3-AC for 28 days. Rivastigmine (2 mg/kg) was the standard. Behavioral tests (EPM, MWM) were performed at 7-day intervals throughout study period. Rats showed improved spatial memory and learning in treatment groups during behavioral tests. Rats were euthanized on day 28. Inflammatory markers (IL-1β, IL-16 and TNFα) exhibited significant improvement (p < 0.001) in treated rats. Oxidative stress enzymes (SOD, CAT, GSH, MDA) were restored. Caspase3 and NF-κβ quantified through qRT-PCR also decreased significantly (p < 0.001) when compared to disease control group. Levels of acetyl cholinesterase, dopamine and noradrenaline were also restored in treated rats significantly (p < 0.001). 3-AC treatment restored neuroprotection probably because of anti-inflammatory, anti-oxidant and anti-cholinesterase potential; hence, this can be considered a promising therapeutic potential alternative.

Signaling Pathways Involved in the Neuroprotective Effect of Osthole: Evidence and Mechanisms

Neurodegenerative diseases constitute a major threat to human health and are usually accompanied by progressive structural and functional loss of neurons. Abnormalities in synaptic plasticity are involved in neurodegenerative disorders. Aberrant cell signaling cascades play a predominant role in the initiation, progress as well as in the severity of these ailments. Notch signaling is a pivotal role in the maintenance of neural stem cells and also participates in neurogenesis. PI3k/Akt cascade regulates different biological processes including cell proliferation, apoptosis, and metabolism. It regulates neurotoxicity and mediates the survival of neurons. Moreover, the activated BDNF/TrkB cascade is involved in promoting the transcription of genes responsible for cell survival and neurogenesis. Despite significant progress made in delineating the underlying pathological mechanisms involved and derangements in cellular metabolic promenades implicated in these diseases, satisfactory strategies for the clinical management of these ailments are yet to be achieved. Therefore, the molecules targeting these cell signaling cascades may emerge as useful leads in developing newer management strategies. Osthole is an important ingredient of traditional Chinese medicinal plants, often found in various plants of the Apiaceae family and has been observed to target these aforementioned mediators. Until now, no review has been aimed to discuss the possible molecular signaling cascades involved in osthole-mediated neuroprotection at one platform. The current review aimed to explore the interplay of various mediators and the modulation of the different molecular signaling cascades in osthole-mediated neuroprotection. This review could open new insights into research involving diseases of neuronal origin, especially the effect on neurodegeneration, neurogenesis, and synaptic plasticity. The articles gathered to compose the current review were extracted by using the PubMed, Scopus, Science Direct, and Web of Science databases. A methodical approach was used to integrate and discuss all published original reports describing the modulation of different mediators by osthole to confer neuroprotection at one platform to provide possible molecular pathways. Based on the inclusion and exclusion criteria, 32 articles were included in the systematic review. Moreover, literature evidence was also used to construct the biosynthetic pathway of osthole. The current review reveals that osthole promotes neurogenesis and neuronal functioning via stimulation of Notch, BDNF/Trk, and P13k/Akt signaling pathways. It upregulates the expression of various proteins, such as BDNF, TrkB, CREB, Nrf-2, P13k, and Akt. Activation of Wnt by osthole, in turn, regulates downstream GSK-1β to inhibit tau phosphorylation and β-catenin degradation to prevent neuronal apoptosis. The activation of Wnt and inhibition of oxidative stress, Aβ, and GSK-3β mediated β-catenin degradation by osthole might also be involved in mediating the protection against neurodegenerative diseases. Furthermore, it also inhibits neuroinflammation by suppressing MAPK/NF-κB-mediated transcription of genes involved in the generation of inflammatory cytokines and NLRP-3 inflammasomes. This review delineates the various underlying signaling pathways involved in mediating the neuroprotective effect of osthole. Modulation of Notch, BDNF/Trk, MAPK/NF-κB, and P13k/Akt signaling pathways by osthole confers protection against neurodegenerative diseases. The preclinical effects of osthole suggest that it could be a valuable molecule in inspiring the development of new drugs for the management of neurodegenerative diseases and demands clinical studies to explore its potential. An effort has been made to unify the varied mechanisms and target sites involved in the neuroprotective effect of osthole. The comprehensive description of the molecular pathways in the present work reflects its originality and thoroughness. The reviewed literature findings may be extrapolated to suggest the role of othole as a "biological response modifier" which contributes to neuroprotection through kinase modulatory, immunomodulatory, and anti-oxidative activity, which is documented even at lower doses. The current review attempts to emphasize the gaps in the existing literature which can be explored in the future.

The Gut-Brain Axis as a Therapeutic Target in Multiple Sclerosis

The CNS is very susceptible to oxidative stress; the gut microbiota plays an important role as a trigger of oxidative damage that promotes mitochondrial dysfunction, neuroinflammation, and neurodegeneration. In the current review, we discuss recent findings on oxidative-stress-related inflammation mediated by the gut-brain axis in multiple sclerosis (MS). Growing evidence suggests targeting gut microbiota can be a promising strategy for MS management. Intricate interaction between multiple factors leads to increased intra- and inter-individual heterogeneity, frequently painting a different picture in vivo from that obtained under controlled conditions. Following an evidence-based approach, all proposed interventions should be validated in clinical trials with cohorts large enough to reach significance. Our review summarizes existing clinical trials focused on identifying suitable interventions, the suitable combinations, and appropriate timings to target microbiota-related oxidative stress. Most studies assessed relapsing-remitting MS (RRMS); only a few studies with very limited cohorts were carried out in other MS stages (e.g., secondary progressive MS-SPMS). Future trials must consider an extended time frame, perhaps starting with the perinatal period and lasting until the young adult period, aiming to capture as many complex intersystem interactions as possible.

Natural Coumarin Derivatives Activating Nrf2 Signaling Pathway as Lead Compounds for the Design and Synthesis of Intestinal Anti-Inflammatory Drugs

Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor related to stress response and cellular homeostasis that plays a key role in maintaining the redox system. The imbalance of the redox system is a triggering factor for the initiation and progression of non-communicable diseases (NCDs), including Inflammatory Bowel Disease (IBD). Nrf2 and its inhibitor Kelch-like ECH-associated protein 1 (Keap1) are the main regulators of oxidative stress and their activation has been recognized as a promising strategy for the treatment or prevention of several acute and chronic diseases. Moreover, activation of Nrf2/keap signaling pathway promotes inhibition of NF-κB, a transcriptional factor related to pro-inflammatory cytokines expression, synchronically promoting an anti-inflammatory response. Several natural coumarins have been reported as potent antioxidant and intestinal anti-inflammatory compounds, acting by different mechanisms, mainly as a modulator of Nrf2/keap signaling pathway. Based on in vivo and in vitro studies, this review focuses on the natural coumarins obtained from both plant products and fermentative processes of food plants by gut microbiota, which activate Nrf2/keap signaling pathway and produce intestinal anti-inflammatory activity. Although gut metabolites urolithin A and urolithin B as well as other plant-derived coumarins display intestinal anti-inflammatory activity modulating Nrf2 signaling pathway, in vitro and in vivo studies are necessary for better pharmacological characterization and evaluation of their potential as lead compounds. Esculetin, 4-methylesculetin, daphnetin, osthole, and imperatorin are the most promising coumarin derivatives as lead compounds for the design and synthesis of Nrf2 activators with intestinal anti-inflammatory activity. However, further structure-activity relationships studies with coumarin derivatives in experimental models of intestinal inflammation and subsequent clinical trials in health and disease volunteers are essential to determine the efficacy and safety in IBD patients.

The Role of Nrf2 in Relieving Cerebral Ischemia-Reperfusion Injury

Ischemic stroke includes two related pathological damage processes: brain injury caused by primary ischemia and secondary ischemia reperfusion (I/R) injury. I/R injury has become a worldwide health problem. Unfortunately, there is still a lack of satisfactory drugs for ameliorating cerebral I/R damage. Nrf2 is a vital endogenous antioxidant protein, which combines with Keap1 to maintain a dormant state under physiological conditions. When pathological changes such as I/R occurs, Nrf2 dissociates from Keap1 and activates the expression of downstream antioxidant proteins to exert a protective effect. Recent research have shown that the activated Nrf2 not only effectively inhibits oxidative stress, but also performs the ability to repair the function of compromised mitochondria, alleviate endoplasmic reticulum stress, eliminate inflammatory response, reduce blood-brain barrier permeability, inhibit neuronal apoptosis, enhance the neural network remolding, thereby exerting significant protective effects in alleviating the injuries caused by cell oxygen-glucose deprivation, or animal cerebral I/R. However, no definite clinical application report demonstrated the efficacy of Nrf2 activators in the treatment of cerebral I/R. Therefore, further efforts are needed to elaborate the role of Nrf2 activators in the treatment of cerebral I/R. Here, we reviewed the possible mechanisms underlying its potential pharmacological benefits in alleviating cerebral I/R injury, so as to provide a theoretical basis for studying its mechanism and developing Nrf2 activators.

Multi-Target Mechanisms of Phytochemicals in Alzheimer’s Disease: Effects on Oxidative Stress, Neuroinflammation and Protein Aggregation

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by a tangle-shaped accumulation of beta-amyloid peptide fragments and Tau protein in brain neurons. The pathophysiological mechanism involves the presence of Aβ-amyloid peptide, Tau protein, oxidative stress, and an exacerbated neuro-inflammatory response. This review aims to offer an updated compendium of the most recent and promising advances in AD treatment through the administration of phytochemicals. The literature survey was carried out by electronic search in the following specialized databases PubMed/Medline, Embase, TRIP database, Google Scholar, Wiley, and Web of Science regarding published works that included molecular mechanisms and signaling pathways targeted by phytochemicals in various experimental models of Alzheimer’s disease in vitro and in vivo. The results of the studies showed that the use of phytochemicals against AD has gained relevance due to their antioxidant, anti-neuroinflammatory, anti-amyloid, and anti-hyperphosphorylation properties of Tau protein. Some bioactive compounds from plants have been shown to have the ability to prevent and stop the progression of Alzheimer’s.

BaZiBuShen alleviates cognitive deficits and regulates Sirt6/NRF2/HO-1 and Sirt6/P53-PGC-1α-TERT signaling pathways in aging mice

ETHNOPHARMACOLOGICAL RELEVANCE

BaZiBuShen formula (BZBS) is clinically used to counteract mental fatigue and to retard the aging process. Brain aging echoes in major risks of human sufferings and has become one of the main challenges to our societies and the health-care systems.

AIM OF THE STUDY

To investigate the effect and mode of action of BZBS on aging-associated cognitive impairments.

MATERIALS AND METHODS

BZBS was orally administered to D-galactose and NaNO2-induced aging mice. Premature senescence was assessed using the Morris water maze, step-down type passive avoidance, and pole-climbing tests. Telomere length was examined by qPCR analysis. Telomerase activity was assessed using PCR ELISA assay. Mitochondrial complex IV activity was examined by biochemical test. The levels of redox and immune status were determined by ELISA or biochemical assay. The expressions of sirtuin 6 (Sirt6), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), P53, telomerase reverse transcriptase (TERT), heme oxygenase-1 (HO-1), phospho(p)-nuclear factor erythroid-2 related factor 2 (NRF2), caspase-3, Bcl-2 associated x (Bax), and B-cell lymphoma-2 (Bcl-2) in the cerebral cortex were examined by Western blot and/or immunohistochemical staining.

RESULTS

BZBS intervention ameliorated reduced brain performances in aging mice, including memory, cognitive, and motor functions. In addition, BZBS administration to aging mice preserved redox homeostasis, attenuated immunosenescence, and maintained telomerase activity and telomere length. Moreover, BZBS treatment were associated with a declines in P53, caspase-3, Bax expressions and an increase in Sirt6, p-HO-1, p-NRF2, PGC-1α, and Bcl-2 expressions in the brains of this rapid aging mouse.

CONCLUSIONS

BZBS attenuates premature senescence possibly via the preservation of redox homeostasis and telomere integrity, and inhibition of apoptosis in rapid aging mouse. The mechanism governing the alterations may be associated with through the activation of Sirt6/NRF2/HO-1 and Sirt6/P53-PGC-1α-TERT signaling pathways. The results suggest that BZBS may provide a novel strategy for confronting aging and age-associated diseases.

Osthole: an overview of its sources, biological activities, and modification development

Osthole, also known as osthol, is a coumarin derivative found in several medicinal plants such as Cnidium monnieri and Angelica pubescens. It can be obtained via extraction and separation from plants or total synthesis. Plenty of experiments have suggested that osthole exhibited multiple biological activities covering antitumor, anti-inflammatory, neuroprotective, osteogenic, cardiovascular protective, antimicrobial, and antiparasitic activities. In addition, there has been some research done on the optimization and modification of osthole. This article summarizes the comprehensive information regarding the sources and modification progress of osthole. It also introduces the up-to-date biological activities of osthole, which could be of great value for its use in future research.

Osthole-Loaded Nanoemulsion Enhances Brain Target in the Treatment of Alzheimer's Disease via Intranasal Administration

Osthole (OST) is a natural coumarin compound that exerts multiple pharmacologic effects. However, the poor water solubility and the low oral absorption of OST limit its clinical application for the treatment of neurologic diseases. A suitable preparation needs to be tailored to evade these unfavourable properties of OST. In this study, an OST nanoemulsion (OST-NE) was fabricated according to the pseudoternary phase diagram method, which was generally used to optimize the prescription in light of the solubility of OST in surfactants and cosurfactants. The final composition of OST-NE was 3.6% of ethyl oleate as oil phase, 11.4% of the surfactant (polyethylene glycol ester of 15-hydroxystearic acid: polyoxyethylene 35 castor oil = 1 : 1), 3% of polyethylene glycol 400 as cosurfactant, and 82% of the aqueous phase. The pharmacokinetic study of OST-NE showed that the brain-targeting coefficient of OST was larger by the nasal route than that by the intravenous route. Moreover, OST-NE inhibited cell death, decreased the apoptosis-related proteins (Bax and caspase-3), and enhanced the activity of antioxidant enzymes (superoxide dismutase and glutathione) in L-glutamate-induced SH-SY5Y cells. OST-NE improved the spatial memory ability, increased the acetylcholine content in the cerebral cortex, and decreased the activity of acetylcholinesterase in the hippocampus of Alzheimer's disease model mice. In conclusion, this study indicates that the bioavailability of OST was improved by using the OST-NE via the nasal route. A low dose of OST-NE maintained the neuroprotective effects of OST, such as inhibiting apoptosis and oxidative stress and regulating the cholinergic system. Therefore, OST-NE can be used as a possible alternative to improve its bioavailability in the prevention and treatment of Alzheimer's disease.

Oxidative Stress at the Crossroads of Aging, Stroke and Depression

Epidemiologic studies have shown that in the aging society, a person dies from stroke every 3 minutes and 42 seconds, and vast numbers of people experience depression around the globe. The high prevalence and disability rates of stroke and depression introduce enormous challenges to public health. Accumulating evidence reveals that stroke is tightly associated with depression, and both diseases are linked to oxidative stress (OS). This review summarizes the mechanisms of OS and OS-mediated pathological processes, such as inflammation, apoptosis, and the microbial-gut-brain axis in stroke and depression. Pathological changes can lead to neuronal cell death, neurological deficits, and brain injury through DNA damage and the oxidation of lipids and proteins, which exacerbate the development of these two disorders. Additionally, aging accelerates the progression of stroke and depression by overactive OS and reduced antioxidant defenses. This review also discusses the efficacy and safety of several antioxidants and antidepressants in stroke and depression. Herein, we propose a crosstalk between OS, aging, stroke, and depression, and provide potential therapeutic strategies for the treatment of stroke and depression.

Enriched environment improves post-stroke cognitive impairment and inhibits neuroinflammation and oxidative stress by activating Nrf2-ARE pathway

INTRODUCTION

Neuroinflammation and oxidative stress are major mechanisms of post-stroke cognitive impairment (PSCI) neural injury and decreased spatial and memory capacity. Enriched environment (EE) is an effective method to improve cognitive dysfunction. However, the regulation by EE of neuroinflammation, oxidative stress and associated mechanisms in animal models remains unclear.

MATERIALS AND METHODS

In this study, a rat PSCI model was established by middle cerebral artery occlusion (MCAO). Rats were randomly divided into the control group, standard environment (SE) group and EE group for 28 days. A Morris water-maze test was used to measure cognitive function at 7, 14 and 28 days after MCAO. Rats were sacrificed on the 28th day. Quantitative PCR, immunohistochemistry and ELISA were respectively used to detect mRNA expression of NF-E2-related factor 2 (Nrf2) and Nrf2 response genes, the expression of IL-1β and levels of proinflammatory cytokines in the hippocampus.

RESULTS

EE improved mNSS scores and cognitive ability in PSCI rats. EE increased mRNA expression of the Nrf2 and Nrf2 response genes, including heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). EE significantly decreased the level of malondialdehyde (MDA) and increased the levels of superoxide dismutase (SOD) and glutathione (GSH), in the hippocampus of PSCI rats. EE reduced the number of IL-1β positive cells in the hippocampus, and IL-1β levels in the hippocampus and serum. EE increased GFAP-positive astrocytes in the hippocampus, and BDNF levels in the hippocampus and serum.

CONCLUSIONS

EE can improve cognitive function in PSCI rats by inhibiting neuroinflammation and oxidative stress.

Activation of Nrf2 by Natural Bioactive Compounds: A Promising Approach for Stroke?

Stroke represents one of the main causes of disability and death worldwide. The pathological subtypes of stroke are ischemic stroke, the most frequent, and hemorrhagic stroke. Nrf2 is a transcription factor that regulates redox homeostasis. In stress conditions, Nrf2 translocates inside the nucleus and induces the transcription of enzymes involved in counteracting oxidative stress, endobiotic and xenobiotic metabolism, regulators of inflammation, and others. Different natural compounds, including food and plant-derived components, were shown to be able to activate Nrf2, mediating an antioxidant response. Some of these compounds were tested in stroke experimental models showing several beneficial actions. In this review, we focused on the studies that evidenced the positive effects of natural bioactive compounds in stroke experimental models through the activation of Nrf2 pathway. Interestingly, different natural compounds can activate Nrf2 through multiple pathways, inducing a strong antioxidant response associated with the beneficial effects against stroke. According to several studies, the combination of different bioactive compounds can lead to a better neuroprotection. In conclusion, natural bioactive compounds may represent new therapeutic strategies against stroke.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

Cerebrovascular and Neurological Disorders: Protective Role of NRF2

Cellular defense mechanisms, intracellular signaling, and physiological functions are regulated by electrophiles and reactive oxygen species (ROS). Recent works strongly considered imbalanced ROS and electrophile overabundance as the leading cause of cellular and tissue damage, whereas oxidative stress (OS) plays a crucial role for the onset and progression of major cerebrovascular and neurodegenerative pathologies. These include Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), stroke, and aging. Nuclear factor erythroid 2-related factor (NRF2) is the major modulator of the xenobiotic-activated receptor (XAR) and is accountable for activating the antioxidative response elements (ARE)-pathway modulating the detoxification and antioxidative responses of the cells. NRF2 activity, however, is also implicated in carcinogenesis protection, stem cells regulation, anti-inflammation, anti-aging, and so forth. Herein, we briefly describe the NRF2–ARE pathway and provide a review analysis of its functioning and system integration as well as its role in major CNS disorders. We also discuss NRF2-based therapeutic approaches for the treatment of neurodegenerative and cerebrovascular disorders.

NRF2 and NF-қB interplay in cerebrovascular and neurodegenerative disorders: Molecular mechanisms and possible therapeutic approaches

Electrophiles and reactive oxygen species (ROS) play a major role in modulating cellular defense mechanisms as well as physiological functions, and intracellular signaling. However, excessive ROS generation (endogenous and exogenous) can create a state of redox imbalance leading to cellular and tissue damage (Ma and He, 2012) [1]. A growing body of research data strongly suggests that imbalanced ROS and electrophile overproduction are among the major prodromal factors in the onset and progression of several cerebrovascular and neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), stroke, Alzheimer's disease (AD), Parkinson's disease (PD), and aging (Ma and He, 2012; Ramsey et al., 2017; Salminen et al., 2012; Sandberg et al., 2014; Sarlette et al., 2008; Tanji et al., 2013) [1-6]. Cells offset oxidative stress by the action of housekeeping antioxidative enzymes (such as superoxide dismutase, catalase, glutathione peroxidase) as well direct and indirect antioxidants (Dinkova-Kostova and Talalay, 2010) [7]. The DNA sequence responsible for modulating the antioxidative and cytoprotective responses of the cells has been identified as the antioxidant response element (ARE), while the nuclear factor erythroid 2-related factor (NRF2) is the major regulator of the xenobiotic-activated receptor (XAR) responsible for activating the ARE-pathway, thus defined as the NRF2-ARE system (Ma and He, 2012) [1]. In addition, the interplay between the NRF2-ARE system and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB, a protein complex that controls cytokine production and cell survival), has been further investigated in relation to neurodegenerative and neuroinflammatory disorders. On these premises, we provide a review analysis of current understanding of the NRF2-NF-ĸB interplay, their specific role in major CNS disorders, and consequent therapeutic implication for the treatment of neurodegenerative and cerebrovascular diseases.

An enriched environment promotes synaptic plasticity and cognitive recovery after permanent middle cerebral artery occlusion in mice

Cerebral ischemia activates an endogenous repair program that induces plastic changes in neurons. In this study, we investigated the effects of environmental enrichment on spatial learning and memory as well as on synaptic remodeling in a mouse model of chronic cerebral ischemia, produced by subjecting adult male C57BL/6 mice to permanent left middle cerebral artery occlusion. Three days postoperatively, mice were randomly assigned to the environmental enrichment and standard housing groups. Mice in the standard housing group were housed and fed a standard diet. Mice in the environmental enrichment group were housed in a cage with various toys and fed a standard diet. Then, 28 days postoperatively, spatial learning and memory were tested using the Morris water maze. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 in the hippocampus were analyzed by western blot assay. The number of synapses was evaluated by electron microscopy. In the water maze test, mice in the environmental enrichment group had a shorter escape latency, traveled markedly longer distances, spent more time in the correct quadrant (northeast zone), and had a higher frequency of crossings compared with the standard housing group. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 were substantially upregulated in the hippocampus in the environmental enrichment group compared with the standard housing group. Furthermore, electron microscopy revealed that environmental enrichment increased the number of synapses in the hippocampal CA1 region. Collectively, these findings suggest that environmental enrichment ameliorates the spatial learning and memory impairment induced by permanent middle cerebral artery occlusion. Environmental enrichment in mice with cerebral ischemia likely promotes cognitive recovery by inducing plastic changes in synapses.

A novel Nrf2 activator, RS9, attenuates secondary brain injury after intracerebral hemorrhage in sub-acute phase

The poor prognosis of intracranial hemorrhage (ICH) is attributed to secondary brain injury (SBI), which is caused by oxidative stress. Blood components induce reactive oxygen species (ROS) over-production and cause cytotoxicity. We focused on the antioxidant system and investigated nuclear factor-erythroid 2-related factor 2 (Nrf2), which is a transcription factor that controls several antioxidant enzymes. We examined the effects of a novel Nrf2 activator, RS9, on SBI after ICH. ICH was induced by injecting autologous blood collected from the jugular vein (25 µL) into the striatum of mice. RS9 (0.2 mg/kg, i.p.) was administrated 0, 24, and 48 h after the induction of ICH. Using the ICH model, we measured brain edema, neurological function, neuronal damage and antioxidant proteins expression. We then investigated the mechanisms responsible for the effects of RS9 in vitro using the SH-SY5Y cell line. We used zinc protoporphyrin (ZnPP), a heme oxygenase-1 (HO-1) inhibitor, to elucidate the relationship between HO-1 expression and cell death in vitro in a hemin injury model. RS9 decreased brain edema, improved neurological deficits, decreased neuronal damage area and up-regulated HO-1 and superoxide dismutase 1 (SOD) expressions in the ICH mouse model. RS9 also suppressed neuronal cell death and ROS over-production in vitro. These protective effects were cancelled by the ZnPP co-treatment. Our results suggest that the activation of Nrf2 by RS9 exerts neuroprotective effects that are mediated by the attenuation of oxidative stress, and also that RS9 is an effective therapeutic candidate for the treatment for SBI after ICH.

Involvement of CYP2E1 in the Course of Brain Edema Induced by Subacute Poisoning With 1,2-Dichloroethane in Mice

This study was designed to explore the role of cytochrome P4502E1 (CYP2E1) expression in the course of brain edema induced by subacute poisoning with 1,2-dichloroethane (1,2-DCE). Mice were randomly divided into five groups: the control group, the 1,2-DCE poisoned group, and the low-, medium- and high-dose diallyl sulfide (DAS) intervention groups. The present study found that CYP2E1 expression levels in the brains of the 1,2-DCE-poisoned group were upregulated transcriptionally; in contrast, the levels were suppressed by DAS pretreatment in the intervention groups. In addition, the expression levels of both Nrf2 and HO-1 were also upregulated transcriptionally in the brains of the 1,2-DCE-poisoned group, while they were suppressed dose-dependently in the intervention groups. Moreover, compared with the control group, MDA levels and water contents in the brains of the 1,2-DCE-poisoned group increased, whereas NPSH levels and tight junction (TJ) protein levels decreased significantly. Conversely, compared with the 1,2-DCE- poisoned group, MDA levels and water contents in the brains of the intervention groups decreased, and NPSH levels and TJ protein levels increased significantly. Furthermore, pathological changes of brain edema observed in the 1,2-DCE-poisoned group were markedly improved in the intervention groups. Collectively, our results suggested that CYP2E1 expression could be transcriptionally upregulated in 1,2-DCE-poisoned mice, which might enhance 1,2-DCE metabolism in vivo, and induce oxidative damage and TJ disruption in the brain, ultimately leading to brain edema.

Phyto-Therapeutic and Nanomedicinal Approaches to Cure Alzheimer's Disease: Present Status and Future Opportunities

Alzheimer's disease (AD) is characterized by cognitive inability manifested due to the accumulation of β-amyloid, formation of hyper phosphorylated neurofibrillary tangles, and a malfunctioned cholinergic system. The degeneration integrity of the neuronal network can appear long after the onset of the disease. Nanotechnology-based interventions have opened an exciting area via theranostics of AD in terms of tailored nanomedicine, which are able to target and deliver drugs across the blood-brain barrier (BBB). The exciting interface existing between medicinal plants and nanotechnology is an emerging marvel in medicine, which has delivered promising results in the treatment of AD. In order to assess the potential applications of the medicinal plants, their derived components, and various nanomedicinal approaches, a review of literature was deemed as necessary. In the present review, numerous phytochemicals and various feats in nanomedicine for the treatment of AD have been discussed mechanistically for the first time. Furthermore, recent trends in nanotechnology such as green synthesis of metal nanoparticles with reference to the treatment of AD have been elaborated. Foreseeing the recent progress, we hope that the interface of medicinal plants and nanotechnology will lead to highly effective theranostic strategies for the treatment of AD in the near future.

The novel chalcone analog L2H17 protects retinal ganglion cells from oxidative stress-induced apoptosis

Chalcone is a plant metabolite widely found in fruits, vegetables, spices and tea, and has anti-tumor, anti-inflammation, immunomodulation, antibacterial and anti-oxidation activities, as well as many other pharmacological and biological effects. Our team has shown that its analogs have antioxidant activity, and oxidative stress is a pathological hallmark of retinal ischemia/reperfusion injury that can lead to retinal damage and visual loss. This investigation aims to identify a chalcone that protects retinal ganglion cells in vitro from the effects of oxidative stress and examine its mechanism. Rat retinal ganglion cell-5 cells were pretreated with chalcones and then exposed to tert-butyl hydroperoxide that causes oxidative damage. Controls received dimethyl sulfoxide only or tert-butyl hydroperoxide in dimethyl sulfoxide. Only (E)-3,4-dihydroxy-2'-methylether ketone (L2H17), of the five chalcone analogs, markedly increased the survival rate of oxidatively injured RGC-5 cells. Thus, subsequent experiments only analyzed the results of the L2H17 intervention. Cell viability and apoptosis were measured. Intracellular superoxide dismutase and reactive oxygen species levels were used to assess induced oxidative stress. The mechanism of action by L2H17 was explored by measuring the ER stress/UPR pathway and the expression and localization of Nrf2. All results demonstrated that L2H17 could reduce the apoptosis of oxidatively injured cells, inhibit caspase-3 activity, increase Bcl-2 expression, decrease Bad expression, increase the activity of superoxide dismutase, inhibit the production of reactive oxygen species, increase Nrf2 immunoreactivity, and reduce the activating transcription factor 4, phospho-eukaryotic initiation factor 2 and CHOP expression. L2H17 protects retinal ganglion cells induced by oxidative stress by regulating Nrf2, which indicates that it has the potential to become a drug for retinal ischemia/reperfusion.

Osthole Delays Tert-Butyl Hydroperoxide-Induced Premature Senescence in Neural Stem Cells

In our previous study, we found that osthole could promote the ability of proliferation and differentiation in normal neural stem cells (NSCs) under normal condition. Then, we used tert-butyl hydroperoxide (t-BHP) to establish the model of senescence NSCs to detect the effects of osthole. Interestingly, the immunofluorescence results showed that osthole (100 μM) could enhance the ability of proliferation and differentiation, and CCK-8 assay results showed that osthole could also enhance the cell viabilities. Then, SA-β-gal assay results showed that osthole could decrease the positive of senescence cells. Flow cytometric analysis results showed that osthole could decrease the mixture of G0 and G1 phase. Reverse transcriptase (RT)-polymerase chain reaction results showed that osthole could downregulate the expression of p16 mRNA, and western blot analysis results showed that the expressions of the target protein decreased in p16-pRb signaling pathway with osthole treatment. In conclusion, these results indicated that osthole could probably delay cells senescence through p16-pRb signaling pathway.

Targeting Protein Quality Control Mechanisms by Natural Products to Promote Healthy Ageing

Organismal ageing is associated with increased chance of morbidity or mortality and it is driven by diverse molecular pathways that are affected by both environmental and genetic factors. The progression of ageing correlates with the gradual accumulation of stressors and damaged biomolecules due to the time-dependent decline of stress resistance and functional capacity, which eventually compromise cellular homeodynamics. As protein machines carry out the majority of cellular functions, proteome quality control is critical for cellular functionality and is carried out through the curating activity of the proteostasis network (PN). Key components of the PN are the two main degradation machineries, namely the ubiquitin-proteasome and autophagy-lysosome pathways along with several stress-responsive pathways, such as that of nuclear factor erythroid 2-related factor 2 (Nrf2), which mobilises cytoprotective genomic responses against oxidative and/or xenobiotic damage. Reportedly, genetic or dietary interventions that activate components of the PN delay ageing in evolutionarily diverse organisms. Natural products (extracts or pure compounds) represent an extraordinary inventory of highly diverse structural scaffolds that offer promising activities towards meeting the challenge of increasing healthspan and/or delaying ageing (e.g., spermidine, quercetin or sulforaphane). Herein, we review those natural compounds that have been found to activate proteostatic and/or anti-stress cellular responses and hence have the potential to delay cellular senescence and/or in vivo ageing.

Efficacy of Osthole in Management of Hypoperfused Retina

Purpose

To determine the effect of osthole on the retina in a chronic cerebral hypoperfusion (CCH) rat model and to investigate its therapeutic activity.

Methods

Seventy-two rats were randomly allocated into 6 groups. CCH was induced by permanent bilateral common carotid artery occlusion (BCCAO) in five groups. Sham surgery was performed without occlusion of the artery in the sixth group (control group). Animals were administered with saline (model group), osthole (osthole-IG group), aspirin (aspirin group), or ginaton (ginaton group); the osthole-PI group was performed with peribulbar injection of osthole. Four rats in each group were sacrificed every 5 days after drug administration, and histopathology along with morphology of retina were observed. Fundus fluorescein angiography was performed before the animals were sacrificed at day 15. Retinal Akt, NF-κB, Bax, and Bcl-2 levels were assessed using immunohistochemistry, immunofluorescence, and reverse-transcription PCR; retinal injury was assessed using TUNEL in situ; retinal levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured.

Results

Fundus fluorescein angiography revealed the retinal vascular diameter in the osthole-IG group rats to be wider than that in the model, osthole-PI, aspirin, or ginaton group rats. Histological analysis of retinal tissue revealed an increase in retinal thickness in all treatment groups, and significant improvement was noticed in the osthole-IG group. TUNEL staining revealed fewer apoptotic cells in the osthole-IG and osthole-PI groups than in the other groups. For immunohistochemistry results, in the osthole-IG group, levels of NF-κB and Akt were lower than those in the other treated groups, while levels of the ratio Bcl-2/Bax were higher. Levels of MDA were lower and levels of SOD were higher in the osthole-IG group than in the other groups.

Conclusions

Osthole protects the retina from ischemia injury secondary to CCH induced by BCCAO, mainly through anti-inflammatory, antioxidant, and antiapoptotic effects.

Osthole induces human nasopharyngeal cancer cells apoptosis through Fas-Fas ligand and mitochondrial pathway

Nasopharyngeal carcinoma (NPC) is endemic in Southern China and Southeast Asia. The present study investigated the activity of osthole in suppressing NPC along with the underlying mechanism. Cell growth inhibition was measured using the MTT assay. Apoptosis was detected through 4',6-diamidino-2-phenylindole staining and flow cytometry. Western blotting was used to identify the signaling pathway. Osthole markedly inhibited cell proliferation and induced apoptosis in the NPC cell line. Western blotting results revealed the increased activation of caspases 3, 8, and 9 and poly (ADP-ribose) polymerase. Osthole treatment significantly reduced the expression of the antiapoptotic protein Bcl-2 and increased the expression of the proapoptotic proteins Bax, Bak, BimL, BimS, and t-Bid. Osthole treatment also increased the expression of Fas, FADD, TNF-R1, TNF-R2, DcR2, RIP, and DR5. In addition, osthole treatment significantly increased the expression levels of phosphorylated ERK1/2 and JNK1/2. These results suggested that osthole exerts cytotoxic effects on NPC cell lines mainly through apoptosis mediated by the Fas-Fas ligand and mitochondrial pathway. Osthole could be a potential anticancer agent for NPC.

Astragaloside IV protects blood-brain barrier integrity from LPS-induced disruption via activating Nrf2 antioxidant signaling pathway in mice

Endothelial cells of cerebral microvessels are one of the components of blood-brain-barrier (BBB), which are connected by tight junctions (TJs). BBB disruption in cerebral diseases such as ischemic stroke, Alzhemer's disease, multiple sclerosis and traumatic brain injury is implicated to exacerbate the disease progression. Astragaloside IV (ASIV) isolated from Astragalus membranaceus prevents BBB breakdown in rodents induced with cerebral edema and experimental autoimmune encephalomyelitis. However, its underlying molecular mechanism has not been elucidated yet. In present study, ASIV was found to prevent the leakage of BBB in LPS-induced mice, which was accompanied with increased zo-1 and occludin but reduced VCAM-1 in brain microvessels. Similarly, in brain endothelial cell line bEnd.3 cells, ASIV mitigated the increased permeability induced by LPS, as evidenced by increased TEER and reduced sodium fluorescein extravasation. ASIV also enhanced the expression of TJ proteins such as zo-1, occludin and claudin-5 in LPS stimulated bEnd.3 cells. Meanwhile, it inhibited the inflammatory responses and prevented the monocyte adhesion onto bEnd.3 cells upon LPS stimulation. Further study disclosed that ASIV could alleviate ROS level and activate Nrf2 antioxidant pathway in bEnd.3 cells. When Nrf2 was silenced, the protective effect of ASIV was abolished. In brain microvessels of LPS-induced mice, ASIV also enhanced the expression of Nrf2 antioxidant pathway related proteins. Collectively, our results demonstrated that ASIV protected the integrity of BBB in LPS-induced mice, the mechanism of which might be mediated via activating Nrf2 signaling pathway. The findings suggested that ASIV might be a potential neuroprotective drug acting on BBB.

In vitro anticancer activities of osthole against renal cell carcinoma cells

Renal cell carcinoma (RCC) is a common urinary malignancy that is resistant to chemotherapy and radiotherapy. Osthole, a monomer compound extracted from a traditional Chinese herb, has potent anti-tumor effects on various types of cancer cells. However, the therapeutic effects of osthole on RCC remain unclear. In our study, osthole could suppress the proliferation and colony formation of two RCC cell lines, ACHN and 786-O cells, in a dose-dependent manner. Treatment with osthole resulted in a significant, dose-dependent increase in the expression of pro-apoptotic proteins (cleaved caspase-3 and Bax) and decreased expression of anti-apoptotic proteins (Bcl-2 and survivin), which were consistent with evidence of apoptotic nuclear morphology revealed by DAPI staining. Pre-treatment with osthole attenuated the migratory and invasive abilities of RCC cells in a dose-dependent manner, as evidenced by a reduction in migrating cells in a Transwell assay and a decreased wound closure ratio in a scratch assay as compared with the control. Additionally, osthole down-regulated the expression of migration/invasion-related proteins matrix metalloproteinase (MMP)-2 and MMP-9. Osthole significantly up-regulated epithelial biomarkers (E-cadherin and beta-catenin) and down-regulated mesenchymal biomarkers (N-cadherin and vimentin). Furthermore, our results suggest that osthole suppressed the expression of epithelial-mesenchymal transition transcriptional factors Smad-3, Snail-1, and Twist-1. Taken together, the results of this study suggest that osthole might be a potential novel herbal agent against RCC.

Osthole prevents cerebral ischemia-reperfusion injury via the Notch signaling pathway

Stroke is a common cerebrovascular disease in aging populations, and constitutes the second highest principle cause of mortality and the principle cause of permanent disability, and ischemic stroke is the primary form. Osthole is a coumarin derivative extracted from the fruits of Cnidium monnieri (L.) Cusson. In this study, we established a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) in vivo and found that MCAO/R caused cerebral infarction, hippocampus neuronal injury and apoptosis, and also activated the Notch 1 signaling pathway. However, treatment with osthole further enhanced the activity of Notch 1 signaling and reduced the cerebral infarction as well as the hippocampus neuronal injury and apoptosis induced by MCAO/R in a dose-dependent manner. The same results were observed in a primary neuronal oxygen glucose deficiency/reperfusion (OGD/R) model in vitro, and the effect of osthole could be blocked by an inhibitor of Notch 1 signaling, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine tert-butyl ester (DAPT). Therefore, we demonstrated that osthole injection prevented rat ischemia-reperfusion injury via activating the Notch 1 signaling pathway in vivo and in vitro in a dose-dependent manner, which may be significant for clinical treatment of ischemic stroke.

ITH14001, a CGP37157-Nimodipine Hybrid Designed to Regulate Calcium Homeostasis and Oxidative Stress, Exerts Neuroprotection in Cerebral Ischemia

During brain ischemia, oxygen and glucose deprivation induces calcium overload, extensive oxidative stress, neuroinflammation, and, finally, massive neuronal loss. In the search of a neuroprotective compound to mitigate this neuronal loss, we have designed and synthesized a new multitarget hybrid (ITH14001) directed at the reduction of calcium overload by acting on two regulators of calcium homeostasis; the mitochondrial Na⁺/Ca²⁺ exchanger (mNCX) and L-type voltage dependent calcium channels (VDCCs). This compound is a hybrid of CGP37157 (mNCX inhibitor) and nimodipine (L-type VDCCs blocker), and its pharmacological evaluation revealed a moderate ability to selectively inhibit both targets. These activities conferred concentration-dependent neuroprotection in two models of Ca²⁺ overload, such as toxicity induced by high K⁺ in the SH-SY5Y cell line (60% protection at 30 μM) and veratridine in hippocampal slices (26% protection at 10 μM). It also showed neuroprotective effect against oxidative stress, an activity related to its nitrogen radical scavenger effect and moderate induction of the Nrf2-ARE pathway. Its Nrf2 induction capability was confirmed by the increase of the expression of the antioxidant and anti-inflammatory enzyme heme-oxygenase I (3-fold increase). In addition, the multitarget profile of ITH14001 led to anti-inflammatory properties, shown by the reduction of nitrites production induced by lipopolysaccharide in glial cultures. Finally, it showed protective effect in two acute models of cerebral ischemia in hippocampal slices, excitotoxicity induced by glutamate (31% protection at 10 μM) and oxygen and glucose deprivation (76% protection at 10 μM), reducing oxidative stress and iNOS deleterious induction. In conclusion, our hybrid derivative showed improved neuroprotective properties when compared to its parent compounds CGP37157 and nimodipine.

Advance in spinal cord ischemia reperfusion injury: Blood-spinal cord barrier and remote ischemic preconditioning

The blood-spinal cord barrier (BSCB) is the physiological and metabolic substance diffusion barrier between blood circulation and spinal cord tissues. This barrier plays a vital role in maintaining the microenvironment stability of the spinal cord. When the spinal cord is subjected to ischemia/reperfusion (I/R) injury, the structure and function of the BSCB is disrupted, further destroying the spinal cord homeostasis and ultimately leading to neurological deficit. Remote ischemic preconditioning (RIPC) is an approach in which interspersed cycles of preconditioning ischemia is followed by reperfusion to tissues/organs to protect the distant target tissues/organs against subsequent lethal ischemic injuries. RIPC is an innovation of the treatment strategies that protect the organ from I/R injury. In this study, we review the morphological structure and function of the BSCB, the injury mechanism of BSCB resulting from spinal cord I/R, and the effect of RIPC on it.

Osthole confers neuroprotection against cortical stab wound injury and attenuates secondary brain injury

Background

Neuroendoscopy is an innovative technique for neurosurgery that can nonetheless result in traumatic brain injury. The accompanying neuroinflammation may lead to secondary tissue damage, which is the major cause of delayed neuronal death after surgery. The present study investigated the capacity of osthole to prevent secondary brain injury and the underlying mechanism of action in a mouse model of stab wound injury.

Methods

A mouse model of cortical stab wound injury was established by inserting a needle into the cerebral cortex for 20 min to mimic neuroendoscopy. Mice received an intraperitoneal injection of osthole 30 min after surgery and continued for 14 days. Neurological severity was evaluated 12 h and up to 21 days after the trauma. Brains were collected 3–21 days post-injury for histological analysis, immunocytochemistry, quantitative real-time PCR, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and enzyme-linked immunosorbent assays.

Results

Neurological function improved in mice treated with osthole and was accompanied by reduced brain water content and accelerated wound closure relative to untreated mice. Osthole treatment reduced the number of macrophages/microglia and peripheral infiltrating of neutrophils and lowered the level of the proinflammatory cytokines interleukin-6 and tumor necrosis factor α in the lesioned cortex. Osthole-treated mice had fewer TUNEL+ apoptotic neurons surrounding the lesion than controls, indicating increased neuronal survival.

Conclusions

Osthole reduced secondary brain damage by suppressing inflammation and apoptosis in a mouse model of stab wound injury. These results suggest a new strategy for promoting neuronal survival and function after neurosurgery to improve long-term patient outcome.

Effect of Cnidium Lactone on Serum Mutant P53 and BCL-2/BAX Expression in Human Prostate Cancer Cells PC-3 Tumor-Bearing BALB/C Nude Mouse Model

Background

Cnidium lactone is a natural coumarin compound that can inhibit a variety of cancer cell proliferation and induce cancer cell apoptosis. This experiment investigated the effect of cnidium lactone on molecular marker expression in prostate cancer nude mice to study its effect in inducing apoptosis.

Material/Methods

We randomly and equally divided 30 male BALB/C nude mice inoculated with human prostate cancer cells PC-3 into a negative control group, a cyclophosphamide group (500 mg/Kg), and cnidium lactone groups at 3 doses (280 mg/Kg, 140 mg/Kg, and 70 mg/Kg). The mice were weighed at 2 weeks after administration. Tunnel assay was applied to test the nude mice tumor cell apoptosis. ELISA was performed to detect serum AMACR, CD147, mutant P53, BCL-2, AND BAX expression levels. Tumor tissue was separated and weighed.

Results

Mice weight did not change significantly in the groups receiving 3 different doses of cnidium lactone(p>0.05), while it decreased obviously in the cyclophosphamide group (p<0.05). Tumor weight, CD147, mutant P53, and BCL-2 levels were significantly lower in the groups receiving 3 different doses of cnidium lactone than in the negative control group (p<0.05). Among them, the abovementioned indexes decreased markedly in the 280 mg/Kg and 140 mg/Kg dose groups than in the cyclophosphamide group (p<0.05). AMACR and BAX levels showed no significant difference in the cnidium lactone group or the cyclophosphamide group (p>0.05).

Conclusions

Cnidium lactone may induce prostate cancer cell apoptosis and inhibit its proliferation through regulating CD147, mutant P53, and BCL-2 expression in nude mice.

Cnidium monnieri: A Review of Traditional Uses, Phytochemical and Ethnopharmacological Properties

Cnidium monnieri (L.) Cuss., an annual plant of the Umbelliferae species is one of the most widely used traditional herbal medicines and its fruits have been used to treat a variety of diseases in China, Vietnam, and Japan. The aim of this review is to provide an up-to-date and comprehensive analysis of the botany, traditional uses, phytochemistry, pharmacology, toxicity and contraindication of Cnidium monnieri (L.) Cuss. and to provide future directions of research on this plant. To date, 350 compounds have been isolated and identified from Cnidium monnieri (L.) Cuss., including the main active constituent, coumarins. In vitro and in vivo studies suggest that osthole and other coumarin compounds possess wide range of pharmacological properties for the treatment of female genitals, male impotence, frigidity, skin-related diseases, and exhibit strong antipruritic, anti-allergic, antidermatophytic, antibacterial, antifungal, anti-osteoporotic effects. Although coumarins have been identified as the main active constituents responsible for the observed pharmacological effects, the molecular mechanisms of their actions are still unknown. Therefore, further studies are still required to reveal the structure-activity relationship of these active constituents. In addition, toxicological and clinical studies are also required to provide further data for pharmaceutical use.

Systems approach to the study of brain damage in the very preterm newborn

Background: A systems approach to the study of brain damage in very preterm newborns has been lacking.

Methods: In this perspective piece, we offer encephalopathy of prematurity as an example of the complexity and interrelatedness of brain-damaging molecular processes that can be initiated inflammatory phenomena.

Results: Using three transcription factors, nuclear factor-kappa B (NF-κB), Notch-1, and nuclear factor erythroid 2 related factor 2 (NRF2), we show the inter-connectedness of signaling pathways activated by some antecedents of encephalopathy of prematurity.

Conclusions: We hope that as biomarkers of exposures and processes leading to brain damage in the most immature newborns become more readily available, those who apply a systems approach to the study of neuroscience can be persuaded to study the pathogenesis of brain disorders in the very preterm newborn.