Neuroprotective Effects of Curcumin in Cerebral Ischemia: Cellular and Molecular Mechanisms

A Review on Current Aspects of Curcumin-Based Effects in Relation to Neurodegenerative, Neuroinflammatory and Cerebrovascular Diseases

Curcumin is among the most well-studied natural substances, known for its biological actions within the central nervous system, its antioxidant and anti-inflammatory properties, and human health benefits. However, challenges persist in effectively utilising curcumin, addressing its metabolism and passage through the blood-brain barrier (BBB) in therapies targeting cerebrovascular diseases. Current challenges in curcumin's applications revolve around its effects within neoplastic tissues alongside the development of intelligent formulations to enhance its bioavailability. Formulations have been discovered including curcumin's complexes with brain-derived phospholipids and proteins, or its liposomal encapsulation. These novel strategies aim to improve curcumin's bioavailability and stability, and its capability to cross the BBB, thereby potentially enhancing its efficacy in treating cerebrovascular diseases. In summary, this review provides a comprehensive overview of molecular pathways involved in interactions of curcumin and its metabolites, and brain vascular homeostasis. This review explores cellular and molecular current aspects, of curcumin-based effects with an emphasis on curcumin's metabolism and its impact on pathological conditions, such as neurodegenerative diseases, schizophrenia, and cerebral angiopathy. It also highlights the limitations posed by curcumin's poor bioavailability and discusses ongoing efforts to surpass these impediments to harness the full therapeutic potential of curcumin in neurological disorders.

Polyphenols for stroke therapy: the role of oxidative stress regulation

Stroke is associated with a high incidence and disability rate, which seriously endangers human health. Oxidative stress (OS) plays a crucial role in the underlying pathologic progression of cerebral damage in stroke. Emerging experimental studies suggest that polyphenols have antioxidant potential and express protective effects after different types of strokes, but no breakthrough has been achieved in clinical studies. Nanomaterials, due to small characteristic sizes, can be used to deliver drugs, and have shown excellent performance in the treatment of various diseases. The drug delivery capability of nanomaterials has significant implications for the clinical translation and application of polyphenols. This comprehensive review introduces the mechanism of oxidative stress in stroke, and also summarizes the antioxidant effects of polyphenols on reactive oxygen species generation and oxidative stress after stroke. Also, the application characteristics and research progress of nanomaterials in the treatment of stroke with antioxidants are presented.

Phytochemicals in Parkinson's Disease: a Pathway to Neuroprotection and Personalized Medicine

Parkinson's disease (PD) is a complex neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra. While current treatments primarily manage symptoms, there is increasing interest in alternative approaches, particularly the use of phytochemicals from medicinal plants. These natural compounds have demonstrated promising neuroprotective potential in preclinical studies by targeting key pathological mechanisms such as oxidative stress, neuroinflammation, and protein aggregation. However, the clinical translation of these phytochemicals is limited due to a lack of robust clinical trials evaluating their safety, efficacy, and pharmacokinetics. This review provides a comprehensive overview of the neuroprotective potential of phytochemicals in PD management, examining the mechanisms underlying PD pathogenesis and emphasizing neuroprotection. It explores the historical and current research on medicinal plants like Mucuna pruriens, Curcuma longa, and Ginkgo biloba, and discusses the challenges in clinical translation, including ethical and practical considerations and the integration with conventional therapies. It further underscores the need for future research to elucidate mechanisms of action, optimize drug delivery, and conduct rigorous clinical trials to establish the safety and efficacy of phytochemicals, aiming to shape future neuroprotective strategies and develop more effective, personalized treatments for PD.

Rational development of fingolimod nano-embedded microparticles as nose-to-brain neuroprotective therapy for ischemic stroke

Ischemic stroke is one of the major diseases causing varying degrees of dysfunction and disability worldwide. The current management of ischemic stroke poses significant challenges due to short therapeutic windows and limited efficacy, highlighting the pressing need for novel neuroprotective treatment strategies. Previous studies have shown that fingolimod (FIN) is a promising neuroprotective drug. Here, we report the rational development of FIN nano-embedded nasal powders using full factorial design experiments, aiming to provide rapid neuroprotection after ischemic stroke. Flash nanoprecipitation was employed to produce FIN nanosuspensions with the aid of polyvinylpyrrolidone and cholesterol as stabilizers. The optimized nanosuspension (particle size = 134.0 ± 0.6 nm, PDI = 0.179 ± 0.021, physical stability = 72 ± 0 h, and encapsulation efficiency of FIN = 90.67 ± 0.08%) was subsequently spray-dried into a dry powder, which exhibited excellent redispersibility (RdI = 1.09 ± 0.04) and satisfactory drug deposition in the olfactory region using a customized 3D-printed nasal cast (45.4%) and an Alberta Idealized Nasal Inlet model (8.6%) at 15 L/min. The safety of the optimized FIN nano-embedded dry powder was confirmed in cytotoxicity studies with nasal (RPMI 2650 and Calu-3 cells) and brain related cells (SH-SY5Y and PC 12 cells), while the neuroprotective effects were demonstrated by observed behavioral improvements and reduced cerebral infarct size in a middle cerebral artery occlusion mouse stroke model. The neuroprotective effect was further evidenced by increased expression of anti-apoptotic protein BCL-2 and decreased expression of pro-apoptotic proteins CC3 and BAX in brain peri-infarct tissues. Our findings highlight the potential of nasal delivery of FIN nano-embedded dry powder as a rapid neuroprotective treatment strategy for acute ischemic stroke.

Advances in nanoparticle-based therapeutics for ischemic stroke: Enhancing drug delivery and efficacy

Ischemic stroke, characterized by vascular occlusion, has recently emerged as one of the primary causes of mortality and disability worldwide. Conventional treatment modalities, such as thrombolytic and neuroprotective therapies, face numerous challenges, including limited bioavailability, significant neurotoxicity, suboptimal targeting, short half-life, and poor blood-brain barrier (BBB) penetration. Nanoparticle-based drug delivery systems present distinct advantages, such as small size, enhanced lipophilicity, and modifiability, which can potentially address these limitations. Utilizing nanoparticles for drug delivery in ischemic stroke therapy offers improved drug bioavailability, reduced neurotoxicity, enhanced targeted delivery, prolonged drug half-life, and better dissolution kinetics. This review aims to provide a comprehensive overview of current strategies in preclinical studies for managing or preventing ischemic stroke from a nanomaterial perspective, highlighting the advantages and limitations of each approach.

Platelet Membrane-Coated Curcumin-PLGA Nanoparticles Promote Astrocyte-Neuron Transdifferentiation for Intracerebral Hemorrhage Treatment

Intracerebral hemorrhage (ICH) is a hemorrhagic disease with high mortality and disability rates. Curcumin is a promising drug for ICH treatment due to its multiple biological activities, but its application is limited by its poor watersolubility and instability. Herein, platelet membrane-coated curcumin polylactic-co-glycolic acid (PLGA) nanoparticles (PCNPs) are prepared to achieve significantly improved solubility, stability, and sustained release of curcumin. Fourier transform infrared spectra and X-ray diffraction assays indicate good encapsulation of curcumin within nanoparticles. Moreover, it is revealed for the first time that curcumin-loaded nanoparticles can not only suppress hemin-induced astrocyte proliferation but also induce astrocytes into neuron-like cells in vitro. PCNPs are used to treat rat ICH by tail vein injection, using in situ administration as control. The results show that PCNPs are more effective than curcumin-PLGA nanoparticles in concentrating on hemorrhagic lesions, inhibiting inflammation, suppressing astrogliosis, promoting neurogenesis, and improving motor functions. The treatment efficacy of intravenously administered PCNPs is comparable to that of in situ administration, indicating a good targeting effect of PCNPs on the hemorrhage site. This study provides a potent treatment for hemorrhagic injuries and a promising solution for efficient delivery of water-insoluble drugs using composite materials of macromolecules and cell membranes.

Curcuminoids as natural modulators of necroptosis: therapeutic implications

Necroptosis is an emerging form of programmed cell death characterized by necrosis, an inflammatory type of cell death. Necroptosis is primarily initiated by specific mediators that interact with receptor proteins, leading to the activation of protein kinases RIPK1 and RIPK3. These kinases transmit death signals and recruit and phosphorylate mixed lineage kinase domain-like protein (MLKL), which ultimately triggers cell death and necroptosis. Curcuminoids, natural compounds derived from turmeric, have been shown to possess various therapeutic benefits, including neuroprotective, anti-metabolic syndrome, anti-inflammatory, and anti-cancer effects. In this concise overview, we aim to explore the relationship between curcuminoids and the molecular mechanisms of the necroptosis pathway based on recent in vivo and in vitro studies. The available literature indicates that curcuminoids, mainly curcumin, can act as inhibitors of necroptosis in tissue damage scenarios while serving as a necroptosis inducer in cancer cells. Curcuminoids significantly influence key indicators of necroptosis, highlighting their potential to enhance disease treatment. Future studies should focus on further investigating this important component of turmeric to advance therapeutic approaches.

Mitigation of Deoxynivalenol (DON)- and Aflatoxin B1 (AFB1)-Induced Immune Dysfunction and Apoptosis in Mouse Spleen by Curcumin

In the context of the potential immunomodulatory properties of curcumin in counteracting the detrimental effects of concurrent exposure to Deoxynivalenol (DON) and Aflatoxin B1 (AFB1), a comprehensive 28-days trial was conducted utilizing 60 randomly allocated mice divided into four groups. Administration of curcumin at a dosage of 5 mg/kg body weight in conjunction with DON at 0.1 mg/kg and AFB1 at 0.01 mg/kg body weight was undertaken to assess its efficacy. Results indicated that curcumin intervention demonstrated mitigation of splenic structural damage, augmentation of serum immunoglobulin A (IgA) and immunoglobulin G (IgG) levels, elevation in T lymphocyte subset levels, and enhancement in the mRNA expression levels of pro-inflammatory cytokines TNF-α, IFN-γ, IL-2, and IL-6. Furthermore, curcumin exhibited a suppressive effect on apoptosis in mice, as evidenced by decreased activity of caspase-3 and caspase-9, reduced expression levels of pro-apoptotic markers Bax and Cytochrome-c (Cyt-c) at both the protein and mRNA levels, and the maintenance of a balanced expression ratio of mitochondrial apoptotic regulators Bax and Bcl-2. Collectively, these findings offer novel insights into the therapeutic promise of curcumin in mitigating immunosuppression and apoptotic events triggered by mycotoxin co-exposure.

Sweeteners Show a Plasticizing Effect on PVP K30-A Solution for the Hot-Melt Extrusion of Fixed-Dose Amorphous Curcumin-Hesperetin Solid Dispersions

The co-administration of curcumin and hesperetin might be beneficial in terms of neuroprotective activity; therefore, in this study, we attempted to develop a fixed-dose formulation comprising these two compounds in an amorphous state. The aim of obtaining an amorphous state was to overcome the limitations of the low solubility of the active compounds. First, we assessed the possibility of using popular sweeteners (erythritol, xylitol, and sorbitol) as plasticizers to reduce the glass transition temperature of PVP K30 to prepare the polymer-excipient blends, which allowed the preparation of amorphous solid dispersions via hot-melt extrusion at a temperature below the original glass transition of PVP K30. Erythritol proved to be the superior plasticizer. Then, we focused on the development of fixed-dose amorphous solid dispersions of curcumin and hesperetin. Powder X-ray diffraction and thermal analysis confirmed the amorphous character of dispersions, whereas infrared spectroscopy helped to assess the presence of intermolecular interactions. The amorphous state of the produced dispersions was maintained for 6 months, as shown in a stability study. Pharmaceutical parameters such as dissolution rate, solubility, and in vitro permeability through artificial membranes were evaluated. The best improvement in these features was noted for the dispersion, which contained 15% of the total content of the active compounds with erythritol used as the plasticizer.

Interaction between curcumin and ultrafiltered casein micelles or whey protein, and characteristics of their complexes

This work evaluated the interaction between micellar casein (MC) or whey protein (WP) in ultrafiltration retentate with curcumin (Cur), as well as the physicochemical and functional properties of Cur-MC and Cur-WP complexes. The MC had a higher affinity for Cur than WP, shown by higher binding constants of Cur-MC at various temperatures. Thermodynamic analysis of the binding process indicated that the interaction between Cur and MC or WP was hydrophobic in nature. Cur promoted the size and polydispersity index of MC and WP at 4 mM but did not alter the morphology of spray-dried MC and WP. The Cur-MC complexes showed better aqueous solubility at pH 2-3 and 6-10 compared to free MC. Combination with MC or WP improved the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical scavenging activity of Cur. In addition, combination with MC and WP promoted cumulative release of Cur during simulated gastrointestinal digestion, especially for WP. Thus, MC and WP in retentates can be good alternative protein-based carriers for Cur delivery, whereas their complexes in powder form have good functional properties that could be used as active food ingredients in several food formulations. PRACTICAL APPLICATION: Microfiltration is a cheap and convenient approach that can be used to easily produce micellar casein (MC), with whey protein (WP) as one byproduct. In this study, we proved that MC and WP in retentates have strong interaction with curcumin (Cur), whereas their complexes have good functional properties. Thus, spray-dried MC-Cur or WP-Cur complexes could be used as active food ingredients in several food formulations.

Paradigms and Success Stories of Natural Products in Drug Discovery Against Neurodegenerative Disorders (NDDs)

Neurodegenerative disorders (NDDs) are multifaceted complex disorders that have put a great health and economic burden around the globe nowadays. The multi-factorial nature of NDDs has presented a great challenge in drug discovery and continuous efforts are in progress in search of suitable therapeutic candidates. Nature has a great wealth of active principles in its lap that has cured the human population since ancient times. Natural products have revealed several benefits over conventional synthetic medications and scientists have shifted their vision towards exploring the therapeutic potentials of natural products in the past few years. The structural mimicking of natural compounds to endogenous ligands has presented them as a potential therapeutic candidate to prevent the development of NDDs. In the presented review, authors have summarized demographical facts about various NDDs including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and various types of sclerosis in the brain. The significant findings of new active principles of natural origin along with their therapeutic potentials on NDDs have been included. Also, a description of clinical trials and patents on natural products has been enlisted in this compilation. Although natural products have shown promising success in drug discovery against NDDs, still their use is associated with several ethical issues which need to be solved in the upcoming time.

Recent Advances in Chemically Engineered Nanostructures Impact on Ischemic Stroke Treatment

Stroke is a serious public health problem that raises expenses for society and causes long-term impairment and death. However, due to restricted blood-brain barrier (BBB) penetration, there are few treatment alternatives for treating stroke. Recanalization techniques, neuroprotective medications, and recovery techniques are all forms of treatment. The ischemic stroke treatment window is too narrow for logical and efficient therapy, and detection is possible only in advanced stages. BBB integrity disruption, neurotoxicity, and the brief half-life of therapeutic thrombolytics are the key molecular pathogenic causes of ischemic stroke. Existing neuroprotective drugs' inability to promote the recovery of ischemic brain tissue after a stroke is another factor that contributes to the disease's progression, chronic nature, and severity. A possible approach to getting around these medication restrictions and boosting the effectiveness of therapies is nanotechnology. In order to get around these drug-related restrictions and boost the effectiveness of therapies for neurological conditions such as stroke, nanotechnology has emerged as a viable option. These problems might be avoided by using nanoparticle-based methods to create a thrombolytic medication that is safe to use after the tissue plasminogen activator (tPA) treatment window has passed. The idea of using biomimetic nanoparticles in the future for the treatment of ischemic stroke through immunotherapy and stem cell therapy is highlighted, along with recent advancements in the study of nanomaterials for ischemic stroke diagnostics and treatment.

Pharmacological intervention of curcumin via the NLRP3 inflammasome in ischemic stroke

Ischemic-induced neuronal injury arises due to low oxygen/nutrient levels and an inflammatory response that exacerbates neuronal loss. NOD-like receptor family pyrin domain-containing 3 (NLRP3) is an important regulator of inflammation after ischemic stroke, with its inhibition being involved in nerve regeneration. Curcumin, a main active ingredient in Chinese herbs, plays a positive role in neuronal repair and neuroprotection by regulating the NLRP3 signaling pathway. Nevertheless, the signaling mechanisms relating to how curcumin regulates NLRP3 inflammasome in inflammation and neural restoration following ischemic stroke are unknown. In this report, we summarize the main biological functions of the NLRP3 inflammasome along with the neuroprotective effects and underlying mechanisms of curcumin via impairment of the NLRP3 pathway in ischemic brain injury. We also discuss the role of medicinal interventions that target the NLRP3 and potential pathways, as well as possible directions for curcumin therapy to penetrate the blood-brain barrier (BBB) and hinder inflammation in ischemic stroke. This report conclusively demonstrates that curcumin has neuroprotective properties that inhibit inflammation and prevent nerve cell loss, thereby delaying the progression of ischemic brain damage.

Formulation and Characterization of Curcumin Niosomes: Antioxidant and Cytotoxicity Studies

Curcumin's applications in the treatment of conditions including osteoarthritis, dementia, malignancies of the pancreas, and malignancies of the intestines have drawn increasing attention. It has several wonderful qualities, including being an anti-inflammatory agent, an anti-mutagenic agent, and an antioxidant, and has substantially reduced inherent cytotoxicity outcomes. Although curcumin possesses multiple known curative properties, due to its limited bioavailability, it is necessary to develop efficient strategies to overcome these hurdles. To establish an effective administration method, various niosomal formulations were optimized using the Box-Behnken design and assessed in the current investigation. To examine the curcumin niosomes, zeta sizer, zeta potential, entrapment efficiency, SEM, antioxidant potential, cytotoxicity, and release studies were performed. The optimized curcumin niosomes exhibited an average particle size of 169.4 nm, a low PDI of 0.189, and high entrapment efficiency of 85.4%. The release profile showed 79.39% curcumin after 24 h and had significantly higher antioxidant potential as compared with that of free curcumin. The cytotoxicity results of curcumin niosomes presented increased mortality in human ovarian cancer A2780.

Mechanism underlying joint loading and controlled release of β-carotene and curcumin by octenylsuccinated Gastrodia elata starch aggregates

This study aimed to fabricate a novel codelivery system to simultaneously load β-carotene and curcumin in a controlled and synergistic manner. We hypothesized that the aggregates of octenylsuccinated Gastrodia elata starch (OSGES) could efficiently load and control the release of β-carotene and curcumin in combination. Mechanisms underlying the self-assembly of OSGES, coloading, and corelease of β-carotene and curcumin by relevant aggregates were studied. The OSGES could form aggregates with a size of 120.2 nm containing hydrophobic domains surrounded by hydrophilic domains. For coloading, the increased solubilities were attributed to favorable interactions between β-carotene and curcumin as well as interactions with octenyl and starch moieties via hydrophobic and hydrogen-bond interactions, respectively. The β-carotene and curcumin molecules occupied the interior and periphery of hydrophobic domains of OSGES aggregates, respectively, and they did not exist in isolation but interacted with each other. The β-carotene and curcumin combination-loaded OSGES aggregates with a size of 310.5 nm presented a more compact structure than β-carotene-only and curcumin-only loaded OSGES aggregates with sizes of 463.5 and 202.9 nm respectively, suggesting that a transition from a loose cluster to a compact cluster was accompanied by coloading. During in vitro digestion, the joint effect of β-carotene and curcumin prolonged their release and increased their bioaccessibility due to competition between favorable hydrophobic and hydrogen-bond interactions and the unfavorable structure erosion and relaxation of the loaded aggregates. Therefore, OSGES aggregates were designed for the codelivery of β-carotene and curcumin, indicating their potential to be applied in functional foods and dietary supplements.

Curcumin alleviates spleen immunotoxicity induced by decabrominated diphenyl ethers (BDE-209) by improving immune function and inhibiting inflammation and apoptosis in broilers

This study was conducted to assess the mitigating effects of curcumin (Cur) on immunotoxicity in the spleen of broilers induced by the polybrominated diphenyl ether BDE-209. Eighty one-day-old broilers were allocated to the following four groups: control group, BDE-209 (0.4 g/kg) group, BDE-209 (0.4 g/kg) + Cur (0.3 mg/kg) group, and Cur (0.3 mg/kg) group. Growth performance, immunological function, inflammation, and apoptosis were assessed after 42 days of treatment. The findings demonstrate that firstly, Cur restored spleen damage caused by BDE-209 by increasing body weight, decreasing feed-to-gain ratio, correcting the spleen index, and improving the histopathological structure of the spleen. Secondly, Cur relieved BDE-209-induced immunosuppression by increasing the levels of the immunoglobulins IgG, IgM, and IgA in the serum, as well as the levels of white blood cells and lymphocytes. The levels at which GATA binding protein 3, T-box expressed in T cells, interferon-γ, and interleukin (IL)- 4 are expressed were controlled. The ratio of T helper (Th) type 1 (Th1) to Th2 cells in the spleen of broilers was also controlled. Thirdly, Cur reduced the expression of Toll like receptor (TLR) 2, TLR4, nuclear factor (NF)-κB, IL-8, IL-6, and IL-1β, which alleviated BDE-209-induced inflammation in broilers. Cur reduced BDE-209-induced apoptosis by increasing the expression of the bcl-2 protein, decreasing the expression of cleaved caspase-3 and bax proteins, decreasing the bax/bcl-2 protein ratio, and decreasing the mean optical density of TUNEL. These results suggest that Cur protects broiler spleens from BDE-209-induced immunotoxicity via modulating humoral immunity, the equilibrium between Th1 and Th2 cells, the TLRs/NF-κB inflammatory pathway, and the apoptotic pathway.

RIPK1 inhibition contributes to lysosomal membrane stabilization in ischemic astrocytes via a lysosomal Hsp70.1B-dependent mechanism

Receptor-interacting protein kinase 1 (RIPK1) contributes to necroptosis. Our previous study showed that pharmacological or genetic inhibition of RIPK1 protects against ischemic stroke-induced astrocyte injury. In this study, we investigated the molecular mechanisms underlying RIPK1-mediated astrocyte injury in vitro and in vivo. Primary cultured astrocytes were transfected with lentiviruses and then subjected to oxygen and glucose deprivation (OGD). In a rat model of permanent middle cerebral artery occlusion (pMCAO), lentiviruses carrying shRNA targeting RIPK1 or shRNA targeting heat shock protein 70.1B (Hsp70.1B) were injected into the lateral ventricles 5 days before pMCAO was established. We showed that RIPK1 knockdown protected against OGD-induced astrocyte damage, blocked the OGD-mediated increase in lysosomal membrane permeability in astrocytes, and inhibited the pMCAO-induced increase in astrocyte lysosome numbers in the ischemic cerebral cortex; these results suggested that RIPK1 contributed to the lysosomal injury in ischemic astrocytes. We revealed that RIPK1 knockdown upregulated the protein levels of Hsp70.1B and increased the colocalization of Lamp1 and Hsp70.1B in ischemic astrocytes. Hsp70.1B knockdown exacerbated pMCAO-induced brain injury, decreased lysosomal membrane integrity and blocked the protective effects of the RIPK1-specific inhibitor necrostatin-1 on lysosomal membranes. On the other hand, RIPK1 knockdown further exacerbated the pMCAO- or OGD-induced decreases in the levels of Hsp90 and the binding of Hsp90 to heat shock transcription factor-1 (Hsf1) in the cytoplasm, and RIPK1 knockdown promoted the nuclear translocation of Hsf1 in ischemic astrocytes, resulting in increased Hsp70.1B mRNA expression. These results suggest that inhibition of RIPK1 protects ischemic astrocytes by stabilizing lysosomal membranes via the upregulation of lysosomal Hsp70.1B; the mechanism underlying these effects involves decreased Hsp90 protein levels, increased Hsf1 nuclear translocation and increased Hsp70.1B mRNA expression.

Discovery of phenylcarbamoyl xanthone derivatives as potent neuroprotective agents for treating ischemic stroke

Compounds of natural sources are widespread discovered in the treatment of ischemic stroke. Alpha-mangostin, a natural prenylated xanthone, has been found to display a therapeutic potential to treat ischemic stroke. However, the direct application of α-mangostin is limited due to its cytotoxicity and relatively low efficacy. Herein, structural modification of α-mangostin was necessary to improve its drug-ability. Currently, 34 α-mangostin phenylcarbamoyl derivatives were synthesized and evaluated for their neuroprotective activities by glutamate-induced excitotoxicity and H₂O₂-induced oxidative damage models in vitro. The results showed that compound 2 had the most therapeutic potential in both models. Whereafter, 2 has been proved to have powerful therapeutic effects by the MCAO ischemic stroke model in rats, which might be due to inhibition of inflammatory reaction and free radical accumulation. Besides, acute toxicity assay in rats showed that compound 2 had excellent safety. Overall, 2 could be a promising neuroprotective agent for the treatment of ischemic stroke deserving further investigations.

Characteristics and pathogenesis of chemokines in the post-stroke stage

Chemokines, as small molecular proteins, play a crucial role in the immune and inflammatory responses after stroke. A large amount of evidence showed chemokines and their receptors were increasingly recognized as potential targets for stroke treatment, which were involved in the processing of neovascularization, neurogenesis, and neural network reconstruction. In this review, we summarized the characteristics of chemokine alterations throughout the post-stroke nerve repair phase to gain insight into the pathological mechanisms of chemokines and find effective therapeutic targets for stroke.

Novel 2,6-disubstituted benzofuran-3-one analogues improve cerebral ischemia/reperfusion injury via neuroprotective and antioxidative effects

There are no highly effective and safe medicines for clinical treatment of ischemic stroke, although the natural product 3-n-butylphthalide (NBP) has been approved in China for mild and moderate ischemic stroke. To discover more potent anti-cerebral ischemic agents and overcome the low stability by phthalide derivatives, benzofuran-3-one was selected as a core moiety and two types of nitric oxide (NO)-donating groups were incorporated into the structure. In this work, a series of 2,6-disubstituted benzofuran-3-one derivatives were designed and synthesised as NBP analogues, and tested as neuroprotective and antioxidative agents. Compounds 5 (without an NO donor) and 16 (with an NO donor) displayed more potent neuroprotective effects than the established clinical drugs Edaravone and NBP. More importantly, 5 and 16 also exhibited good antioxidative activity without cytotoxicity in rat primary neuronal and PC12 cells. Most active compounds showed good blood-brain barrier permeability in a parallel artificial membrane permeability assay. Furthermore, compound 5 reduced the ischemic infarct area significantly in rats subjected to ischemia/reperfusion injury, downregulated ionised calcium-binding adaptor molecule 1 and glial fibrillary acidic protein in inflammatory cells, and upregulated nerve growth factor.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Curcumin-resveratrol nano-formulation counteracting hyperammonemia in rats

Malnutrition and low dietary protein intake could be risk factors for developing peripheral and central hyperammonemia, especially in pediatrics. Both curcumin and resveratrol proved to be effective against several hepatic and cerebral injuries. They were reported to be beneficial in lowering circulating ammonia levels, yet both are known for their low bioavailability. The use of pharmaceutical nano-formulations as delivery systems for these two nutraceuticals could solve the aforementioned problem. Hence, the present study aimed to investigate the valuable outcome of using a combination of curcumin and resveratrol in a nanoemulsion formulation, to counteract protein-deficient diet (PDD)-induced hyperammonemia and the consequent complications in male albino rats. Results revealed that using a nanoemulsion containing both curcumin and resveratrol at a dose of (5 + 5 mg/kg) effectively reduced hepatic and brain ammonia levels, serum ALT and AST levels, hepatic and brain nitric oxide levels, oxidative DNA damage as well as disrupted cellular energy performance. In addition, there was a substantial increase in brain levels of monoamines, and a decrease in glutamate content. Therefore, it can be concluded that the use of combined curcumin and resveratrol nanoemulsion is an effective means of ameliorating the hepatic and cerebral adverse effects resulting from PDD-induced hyperammonemia in rats.

mTOR (Mammalian Target of Rapamycin): Hitting the Bull's Eye for Enhancing Neurogenesis After Cerebral Ischemia?

Ischemic stroke remains a leading cause of morbidity and disability around the world. The sequelae of serious neurological damage are irreversible due to body's own limited repair capacity. However, endogenous neurogenesis induced by cerebral ischemia plays a critical role in the repair and regeneration of impaired neural cells after ischemic brain injury. mTOR (mammalian target of rapamycin) kinase has been suggested to regulate neural stem cells ability to self-renew and differentiate into proliferative daughter cells, thus leading to improved cell growth, proliferation, and survival. In this review, we summarized the current evidence to support that mTOR signaling pathways may enhance neurogenesis, angiogenesis, and synaptic plasticity following cerebral ischemia, which could highlight the potential of mTOR to be a viable therapeutic target for the treatment of ischemic brain injury.

A Selective Review and Virtual Screening Analysis of Natural Product Inhibitors of the NLRP3 Inflammasome

The NLRP3 inflammasome is currently an exciting target for drug discovery due to its role in various inflammatory diseases; however, to date, no NLRP3 inhibitors have reached the clinic. Several studies have used natural products as hit compounds to facilitate the design of novel selective NLRP3 inhibitors. Here, we review selected natural products reported in the literature as NLRP3 inhibitors, with a particular focus on those targeting gout. To complement this survey, we also report a virtual screen of the ZINC20 natural product database, predicting favored chemical features that can aid in the design of novel small molecule NLRP3 inhibitors.

Neurotransmitters and molecular chaperones interactions in cerebral malaria: Is there a missing link?

Plasmodium falciparum is responsible for the most severe and deadliest human malaria infection. The most serious complication of this infection is cerebral malaria. Among the proposed hypotheses that seek to explain the manifestation of the neurological syndrome in cerebral malaria is the vascular occlusion/sequestration/mechanic hypothesis, the cytokine storm or inflammatory theory, or a combination of both. Unfortunately, despite the increasing volume of scientific information on cerebral malaria, our understanding of its pathophysiologic mechanism(s) is still very limited. In a bid to maintain its survival and development, P. falciparum exports a large number of proteins into the cytosol of the infected host red blood cell. Prominent among these are the P. falciparum erythrocytes membrane protein 1 (PfEMP1), P. falciparum histidine-rich protein II (PfHRP2), and P. falciparum heat shock proteins 70-x (PfHsp70-x). Functional activities and interaction of these proteins with one another and with recruited host resident proteins are critical factors in the pathology of malaria in general and cerebral malaria in particular. Furthermore, several neurological impairments, including cognitive, behavioral, and motor dysfunctions, are known to be associated with cerebral malaria. Also, the available evidence has implicated glutamate and glutamatergic pathways, coupled with a resultant alteration in serotonin, dopamine, norepinephrine, and histamine production. While seeking to improve our understanding of the pathophysiology of cerebral malaria, this article seeks to explore the possible links between host/parasite chaperones, and neurotransmitters, in relation to other molecular players in the pathology of cerebral malaria, to explore such links in antimalarial drug discovery.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

Current Progress on Neuroprotection Induced by Artemisia, Ginseng, Astragalus, and Ginkgo Traditional Chinese Medicines for the Therapy of Alzheimer's Disease

Aging is associated with the occurrence of diverse degenerative changes in various tissues and organs and with an increased incidence of neurological disorders, especially neurodegenerative diseases such as Alzheimer's disease (AD). In recent years, the search for effective components derived from medicinal plants in delaying aging and preventing and treating neurodegenerative diseases has been increasing and the number of related publications shows a rising trend. Here, we present a concise, updated review on the preclinical and clinical research progress in the assessment of the therapeutic potential of different traditional Chinese medicines and derived active ingredients and their effect on the signaling pathways involved in AD neuroprotection. Recognized by their multitargeting ability, these natural compounds hold great potential in developing novel drugs for AD.

Deep eutectic solvents: Recent advances in fabrication approaches and pharmaceutical applications

Deep eutectic solvents (DESs) have received increasing attention in the past decade owing to their distinguished properties including biocompatibility, tunability, thermal and chemical stability. Particularly, DESs have joined forces in pharmaceutical industry, not only to efficiently separate actives from natural products, but also to dramatically increase solubility and permeability of drugs, both are critical for the drug absorption and efficacy. As a result, lately DESs have been extensively and practically adopted as versatile drug delivery systems for different routes such as nasal, transdermal and oral administration with enhanced bioavailability. This review summarizes the emerging progress of DESs by introducing applied fabrication approaches with advantages and limitations thereof, and by highlighting the pharmaceutical applications of DESs.

Inhibition of Oxidative Stress: An Important Molecular Mechanism of Chinese Herbal Medicine (Astragalus membranaceus, Carthamus tinctorius L., Radix Salvia Miltiorrhizae, etc.) in the Treatment of Ischemic Stroke by Regulating the Antioxidant System

Ischemic stroke is a severe cerebrovascular disease with high mortality and morbidity. Traditional Chinese medicine (TCM) has been utilized for thousands of years in China and is becoming increasingly popular all over the world, especially for the treatments of ischemic stroke. More and more evidences have implicated that oxidative stress has been closely related with ischemic stroke. This review will concentrate on the evidence of the action mechanism of Chinese herbal medicine and its active ingredient in preventing ischemic stroke by modulating redox signaling and oxidative stress pathways and providing references for clinical treatment and scientific research applications.

Curcumin Restrains Oxidative Stress of After Intracerebral Hemorrhage in Rat by Activating the Nrf2/HO-1 Pathway

Intracerebral hemorrhage (ICH), a severe hemorrhagic stroke, induces cerebral oxidative stress and severe secondary neurological injury. Curcumin was demonstrated to inhibit oxidative stress in the brain after ICH. However, the pharmacological mechanism needs further research. We used an intrastriatal injection of autologous blood to make the rat ICH model, and then the rat was treated with curcumin (100 mg/kg/day). Modified Neurological Severity Score (mNSS) and corner test results showed that curcumin could significantly promote the neurological recovery of ICH rats. Meanwhile, curcumin could substantially reduce ROS and MDA in the tissues around intracranial hematoma and prevent GSH depletion. To explore the pharmacological molecular mechanism of curcumin, we used HAPI cells and primary rat cortical microglia for in vitro experiments. In vitro, heme-treated cells were used as the cell model of ICH to explore the molecular mechanism of inhibiting oxidative stress by curcumin treatment. The results showed that curcumin significantly inhibited heme-induced oxidative stress, decreased intracellular ROS and MDA, and promoted Nrf2 and its downstream antioxidant gene (HO-1, NQO1, and Gpx4) expression. These results suggest that curcumin inhibits oxidative stress by activating the Nrf2/HO-1 pathway. Here, our results indicate that curcumin can promote the inhibition of oxidative stress in microglia by activating the Nrf2/HO-1 pathway and promoting neurological recovery after ICH, providing a new therapeutic target for clinical treatment of ICH.

Mechanisms Underlying Curcumin-Induced Neuroprotection in Cerebral Ischemia

Ischemic stroke is the leading cause of death and disability worldwide, and restoring the blood flow to ischemic brain tissues is currently the main therapeutic strategy. However, reperfusion after brain ischemia leads to excessive reactive oxygen species production, inflammatory cell recruitment, the release of inflammatory mediators, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, and blood-brain barrier damage; these pathological mechanisms will further aggravate brain tissue injury, ultimately affecting the recovery of neurological functions. It has attracted the attention of researchers to develop drugs with multitarget intervention effects for individuals with cerebral ischemia. A large number of studies have established that curcumin plays a significant neuroprotective role in cerebral ischemia via various mechanisms, including antioxidation, anti-inflammation, anti-apoptosis, protection of the blood-brain barrier, and restoration of mitochondrial function and structure, restoring cerebral circulation, reducing infarct volume, improving brain edema, promoting blood-brain barrier repair, and improving the neurological functions. Therefore, summarizing the results from the latest literature and identifying the potential mechanisms of action of curcumin in cerebral ischemia will serve as a basis and guidance for the clinical applications of curcumin in the future.

Insight Into the Mechanism of Exercise Preconditioning in Ischemic Stroke

Exercise preconditioning has attracted extensive attention to induce endogenous neuroprotection and has become the hotspot in neurotherapy. The training exercise is given multiple times before cerebral ischemia, effectively inducing ischemic tolerance and alleviating secondary brain damage post-stroke. Compared with other preconditioning methods, the main advantages of exercise include easy clinical operation and being readily accepted by patients. However, the specific mechanism behind exercise preconditioning to ameliorate brain injury is complex. It involves multi-pathway and multi-target regulation, including regulation of inflammatory response, oxidative stress, apoptosis inhibition, and neurogenesis promotion. The current review summarizes the recent studies on the mechanism of neuroprotection induced by exercise, providing the theoretical basis of applying exercise therapy to prevent and treat ischemic stroke. In addition, we highlight the various limitations and future challenges of translational medicine from fundamental study to clinical application.

Active Components of Traditional Chinese Medicinal Material for Multiple Myeloma: Current Evidence and Future Directions

Multiple myeloma (MM) is a hematological malignancy characterized by clonal expansion of plasma cells in bone marrow, leading to the overproduction of monoclonal immunoglobulins. The clinical manifestations resulting from monoclonal proteins and malignant cells include signs of end-organ damage, such as hypercalcemia, renal failure, anemia, and bone lesions. Despite improvement in the survival of MM patients with use of myeloma-targeted and immunomodulatory therapies, MM remains an incurable disease. Moreover, patients with relapsed or refractory MM show poor survival outcomes. In recent years, there has been a growing interest in the use of traditional Chinese medicinal materials (TCMMs) for management of a wide spectrum of diseases. The bioactive ingredients derived from TCMMs hold great potential for the development of anticancer drugs. Here we summarize the evidence of the pharmacological effects of the active components in TCMMs on MM, including curcumin, resveratrol, baicalein, berberine, bufalin, cinobufagin, gambogic acid, ginsenoside, icariin, daidzin, formononetin, polysaccharides extracts from Hedyotis difus, and scutellarein. Available evidence indicates that the anti-MM effects of these bioactive ingredients are mediated via regulation of proliferation, apoptosis, autophagy, cell cycle, osteogenic differentiation, and drug resistance. In the future, the underlying mechanisms of the anti-MM effects of these components should be further investigated. Large-scale and well-designed clinical trials are also required to validate the efficacy of these bioactive constituents for MM.

Potential Role of Curcumin for the Treatment of Major Depressive Disorder

Curcumin is the major biologically active polyphenolic constituent in the turmeric plant (Curcuma longa) that has been shown to have antioxidant, anti-inflammatory, neuroprotective, anticancer, antimicrobial, and cardioprotective effects. Interest in curcumin as a treatment for mental health conditions has increased and there is an expanding body of preclinical and clinical research examining its antidepressant and anxiolytic effects. In this narrative review, human trials investigating the effects of curcumin for the treatment of depression or depressive symptoms are summarised. Using findings from in vitro, animal, and human trials, possible biological mechanisms associated with the antidepressant effects of curcumin are also explored. To increase the understanding of curcumin for the treatment of depression, directions for future research are proposed.

|Therapeutic and preventive effects of apigenin in cerebral ischemia: a review

APG can exert various protective effects against cerebral ischemia. Moreover, APG has shown a highly promising ability to prevent cerebral ischemia in terms of regulating blood glucose, blood pressure, lipids and gut microbes.

Curcumin Ameliorates White Matter Injury after Ischemic Stroke by Inhibiting Microglia/Macrophage Pyroptosis through NF-κB Suppression and NLRP3 Inflammasome Inhibition

NLRP3 inflammasome-mediated pyroptosis is a proinflammatory programmed cell death pathway, which plays a vital role in functional outcomes after stroke. We previously described the beneficial effects of curcumin against stroke-induced neuronal damage through modulating microglial polarization. However, the impact of curcumin on microglial pyroptosis remains unknown. Here, stroke was modeled in mice by middle cerebral artery occlusion (MCAO) for 60 minutes and treated with curcumin (150 mg/kg) intraperitoneally immediately after reperfusion, followed by daily administrations for 7 days. Curcumin ameliorated white matter (WM) lesions and brain tissue loss 21 days poststroke and improved sensorimotor function 3, 10, and 21 days after stroke. Furthermore, curcumin significantly reduced the number of gasdermin D⁺ (GSDMD⁺) Iba1⁺ and caspase-1⁺Iba1⁺ microglia/macrophage 21 days after stroke. In vitro, lipopolysaccharide (LPS) with ATP treatment was used to induce pyroptosis in primary microglia. Western blot revealed a decrease in pyroptosis-related proteins, e.g., GSDMD-N, cleaved caspase-1, NLRP3, IL-1β, and IL-18, following in vitro or in vivo curcumin treatment. Mechanistically, both in vivo and in vitro studies confirmed that curcumin inhibited the activation of the NF-κB pathway. NLRP3 knocked down by siRNA transfection markedly increased the inhibitory effects of curcumin on microglial pyroptosis and proinflammatory responses, both in vitro and in vivo. Furthermore, stereotaxic microinjection of AAV-based NLRP3 shRNA significantly improved sensorimotor function and reduced WM lesion following curcumin treatment in MCAO mice. Our study suggested that curcumin reduced stroke-induced WM damage, improved functional outcomes, and attenuated microglial pyroptosis, at least partially, through suppression of the NF-κB/NLRP3 signaling pathway, further supporting curcumin as a potential therapeutic drug for stroke.

Microglia as the Critical Regulators of Neuroprotection and Functional Recovery in Cerebral Ischemia

Microglial activation is considered as the critical pathogenic event in diverse central nervous system disorders including cerebral ischemia. Proinflammatory responses of activated microglia have been well reported in the ischemic brain and neuroinflammatory responses of activated microglia have been believed to be the potential therapeutic strategy. However, despite having proinflammatory roles, microglia can have significant anti-inflammatory roles and they are associated with the production of growth factors which are responsible for neuroprotection and recovery after ischemic injury. Microglia can directly promote neuroprotection by preventing ischemic infarct expansion and promoting functional outcomes. Indirectly, microglia are involved in promoting anti-inflammatory responses, neurogenesis, and angiogenesis in the ischemic brain which are crucial pathophysiological events for ischemic recovery. In fact, anti-inflammatory cytokines and growth factors produced by microglia can promote neuroprotection and attenuate neurobehavioral deficits. In addition, microglia regulate phagocytosis, axonal regeneration, blood-brain barrier protection, white matter integrity, and synaptic remodeling, which are essential for ischemic recovery. Microglia can also regulate crosstalk with neurons and other cell types to promote neuroprotection and ischemic recovery. This review mainly focuses on the roles of microglia in neuroprotection and recovery following ischemic injury. Furthermore, this review also sheds the light on the therapeutic potential of microglia in stroke patients.