Neuronal Uptake and Neuroprotective Properties of Curcumin-Loaded Nanoparticles on SK-N-SH Cell Line: Role of Poly(lactide-co-glycolide) Polymeric Matrix Composition

Curcumin-loaded polymeric nanomaterials as a novel therapeutic strategy for Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) stands as a formidable challenge in modern medicine, characterized by progressive neurodegeneration, cognitive decline, and memory impairment. Despite extensive research, effective therapeutic strategies remain elusive. The antioxidant, anti-inflammatory, and neuroprotective properties of curcumin, found in turmeric, have demonstrated promise. The poor bioavailability and rapid systemic clearance of this drug limit its clinical application. This comprehensive review explores the potential of curcumin-loaded polymeric nanomaterials as an innovative therapeutic avenue for AD. It delves into the preparation and characteristics of diverse polymeric nanomaterial platforms, including liposomes, micelles, dendrimers, and polymeric nanoparticles. Emphasis is placed on how these platforms enhance curcumin's bioavailability and enable targeted delivery to the brain, addressing critical challenges in AD treatment. Mechanistic insights reveal how these nanomaterials modulate key AD pathological processes, including amyloid-beta aggregation, tau phosphorylation, oxidative stress, and neuroinflammation. The review also highlighted the preclinical studies demonstrate reduced amyloid-beta plaques and neuroinflammation, alongside improved cognitive function, while clinical trials show promise in enhancing curcumin's bioavailability and efficacy in AD. Additionally, it addresses the challenges of clinical translation, such as regulatory issues, large-scale production, and long-term stability. By synthesizing recent advancements, this review underscores the potential of curcumin-loaded polymeric nanomaterials to offer a novel and effective therapeutic approach for AD, aiming to guide future research and development in this field.

Exploring Curcumin-Loaded Lipid-Based Nanomedicine as Efficient Targeted Therapy for Alzheimer's Diseases

Alzheimer's disease (AD) is a neurological condition currently with 47 million people suffering from it globally. AD might have many reasons such as genetic issues, environmental factors, and Aβ accumulation, which is the biomarker of the disease. Since the primary reason is unknown, there is no targeted treatment at the moment, but ongoing research aims to slow its progression by managing amyloid-beta peptide production rather than symptomatic improvement. Since phytochemicals have been demonstrated to possess antioxidant, anti-inflammatory, and neuroprotective properties, they may target multiple pathological factors and can reduce the risk of the disease. Curcumin, as a phytochemical found in turmeric known for its antioxidant, free radical scavenging properties, and as an antiamyloid in treating AD, has come under investigation. Although its low bioavailability limits its efficacy, a prominent drug delivery system (DDS) is desired to overcome it. Hence, the potency of lipid-based nanoparticles encapsulating curcumin (LNPs-CUR) is considered in this study as a promising DDS. In vivo studies in animal models indicate LNPs-CUR effectively slow amyloid plaque formation, leading to cognitive enhancement and reduced toxicity compared to free CUR. However, a deeper understanding of CUR's pharmacokinetics and safety profile is crucial before LNPs-CUR can be considered as a medicine. Future investigations may explore the combination of NPs with other therapeutic agents to increase their efficacy in AD cases. This review provides the current position of CUR in the AD therapy paradigm, the DDS suggestions for CUR, and the previous research from the point of analytical view focused on the advantages and challenges.

Nanotechnology in the diagnostic and therapy for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder primarily characterized by β-amyloid plaque, intraneuronal tangles, significant neuronal loss and cognitive deficit. Treatment in the early stages of the disease is crucial for preventing or perhaps reversing the neurodegeneration in the AD cases. However, none of the current diagnostic procedures are capable of early diagnosis of AD. Further, the available treatments merely provide symptomatic alleviation in AD and do not address the underlying illness. Therefore, there is no permanent cure for AD currently. Better therapeutic outcomes need the optimum drug concentration in the central nervous system (CNS) by traversing blood-brain-barrier (BBB). Nanotechnology offers enormous promise to transform the treatment and diagnostics of neurodegenerative diseases. Nanotechnology based diagnostic tools, drug delivery systems and theragnostic are capable of highly sensitive molecular detection, effective drug targeting and their combination. Significant work has been done in this area over the last decade and prospective results have been obtained in AD therapy. This review explores the various applications of nanotechnology in addressing the varied facets of AD, ranging from early detection to therapeutic interventions. This review also looks at how nanotechnology can help with the development of disease-modifying medicines, such as the delivery of anti-amyloid, anti-tau, cholinesterase inhibitors, antioxidants and hormonal drugs. In conclusion, this paper discusses the role of nanotechnology in the early detection of AD, effective drug targeting to the CNS and theragnostic applications in the management of AD.

A supercritical fluid co-extract of turmeric powder and dried coconut shreds shows neuroprotection against AlCl3-induced Alzheimer's disease in rats through nose to brain delivery

This study was aimed at investigating the neuroprotective potential of a co-extract obtained by supercritical fluid extraction (SFE) of turmeric powder and dried coconut shreds against aluminium chloride (AlCl3)-induced Alzheimer's disease (AD) in male Wistar rats. Fifty animals were allocated to five groups, which received saline (vehicle control, group 1), a combination of saline and aluminium chloride (AlCl3) (disease control, group 2), coconut oil (COO) (SFE extracted, treatment group 3), turmeric oleoresin (Cur) (SFE extracted, treatment group 4) and SFE co-extract of turmeric powder and coconut shreds (CurCOO) (treatment group 5). Animals were subjected to behavioural evaluation. In addition, the hippocampal section of the brain from all groups was subjected to biochemical, molecular and histopathological evaluations. The results showed CurCOO administered intranasally improved cognitive abilities, reversed histological alterations in the brain, reduced hippocampus inflammation studied through proinflammatory cytokine markers like TNF-α and IL-6 as compared to the disease control group. The impact of CurCOO on preventive neurodegeneration was also observed through a reduction in protein transcription factor NF-kB in the treated group 5 as compared to a disease control group. The effect of intranasal delivery of CurCOO on the neurons responsible for memory consolidation was evident from low acetylcholinesterase (AChE) enzyme activity in the treated groups with respect to AlCl3 induced group. Summarily, the results demonstrated intranasal delivery of CurCOO to show better efficacy than Cur and COO in preventing neurodegeneration associated with AlCl3 induced Alzheimer's disease.

Application of Nanocomposites and Nanoparticles in Treating Neurodegenerative Disorders

Neurodegenerative diseases represent a formidable global health challenge, affecting millions and imposing substantial burdens on healthcare systems worldwide. Conditions, like Alzheimer's, Parkinson's, and Huntington's diseases, among others, share common characteristics, such as neuronal loss, misfolded protein aggregation, and nervous system dysfunction. One of the major obstacles in treating these diseases is the presence of the blood-brain barrier, limiting the delivery of therapeutic agents to the central nervous system. Nanotechnology offers promising solutions to overcome these challenges. In Alzheimer's disease, NPs loaded with various compounds have shown remarkable promise in preventing amyloid-beta (Aβ) aggregation and reducing neurotoxicity. Parkinson's disease benefits from improved dopamine delivery and neuroprotection. Huntington's disease poses its own set of challenges, but nanotechnology continues to offer innovative solutions. The promising developments in nanoparticle-based interventions for neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS), have offered new avenues for effective treatment. Nanotechnology represents a promising frontier in biomedical research, offering tailored solutions to the complex challenges posed by neurodegenerative diseases. While much progress has been made, ongoing research is essential to optimize nanomaterial designs, improve targeting, and ensure biocompatibility and safety. Nanomaterials possess unique properties that make them excellent candidates for targeted drug delivery and neuroprotection. They can effectively bypass the blood-brain barrier, opening doors to precise drug delivery strategies. This review explores the extensive research on nanoparticles (NPs) and nanocomposites in diagnosing and treating neurodegenerative disorders. These nanomaterials exhibit exceptional abilities to target neurodegenerative processes and halt disease progression.

The Recent Applications of PLGA-Based Nanostructures for Ischemic Stroke

With the accelerated development of nanotechnology in recent years, nanomaterials have become increasingly prevalent in the medical field. The poly (lactic acid-glycolic acid) copolymer (PLGA) is one of the most commonly used biodegradable polymers. It is biocompatible and can be fabricated into various nanostructures, depending on requirements. Ischemic stroke is a common, disabling, and fatal illness that burdens society. There is a need for further improvement in the diagnosis and treatment of this disease. PLGA-based nanostructures can facilitate therapeutic compounds' passage through the physicochemical barrier. They further provide both sustained and controlled release of therapeutic compounds when loaded with drugs for the treatment of ischemic stroke. The clinical significance and potential of PLGA-based nanostructures can also be seen in their applications in cell transplantation and imaging diagnostics of ischemic stroke. This paper summarizes the synthesis and properties of PLGA and reviews in detail the recent applications of PLGA-based nanostructures for drug delivery, disease therapy, cell transplantation, and the imaging diagnosis of ischemic stroke.

Therapeutic Potential of Nanomedicine in Management of Alzheimer's Disease and Glioma

Neoplasm (Glioblastoma) and Alzheimer's disease (AD) comprise two of the most chronic psychological ailments. Glioblastoma is one of the aggressive and prevalent malignant diseases characterized by rapid growth and invasion resulting from cell migration and degradation of extracellular matrix. While the latter is characterized by extracellular plaques of amyloid and intracellular tangles of tau proteins. Both possess a high degree of resistance to treatment owing to the restricted transport of corresponding drugs to the brain protected by the blood-brain barrier (BBB). Development of optimized therapies using advanced technologies is a great need of today. One such approach is the designing of nanoparticles (NPs) to facilitate the drug delivery at the target site. The present article elaborates the advances in nanomedicines in treatment of both AD as well as Gliomas. The intention of this review is to provide an overview of different types of NPs with their physical properties emphasizing their importance in traversing the BBB and hitting the target site. Further, we discuss the therapeutic applications of these NPs along with their specific targets. Multiple overlapping factors with a common pathway in development of AD and Glioblastoma are discussed in details that will assist the readers in developing the conceptual approach to target the NP for an aging population in the given circumstances with limitations of currently designed NPs, and the challenges to meet and the future perspectives.

Ferulic acid-loaded polymeric nanoparticles prepared from nano-emulsion templates facilitate internalisation across the blood-brain barrier in model membranes

A hydroxycinnamic acid derivative, namely ferulic acid (FA) has been successfully encapsulated in polymeric nanoparticles (NPs) based on poly(lactic-co-glycolic acid) (PLGA). FA-loaded polymeric NPs were prepared from O/W nano-emulsion templates using the phase inversion composition (PIC) low-energy emulsification method. The obtained PLGA NPs exhibited high colloidal stability, good drug-loading capacity, and particle hydrodynamic diameters in the range of 74 to 117 nm, depending on the FA concentration used. In vitro drug release studies confirmed a diffusion-controlled mechanism through which the amount of released FA reached a plateau at 60% after 6 hours-incubation. Five kinetic models were used to fit the FA release data as a function of time. The Weibull distribution and Korsmeyer-Peppas equation models provided the best fit to our experimental data and suggested quasi-Fickian diffusion behaviour. Moderate dose-response antioxidant and radical scavenging activities of FA-loaded PLGA NPs were demonstrated using the DPPH˙ assay achieving inhibition activities close to 60 and 40%, respectively. Cell culture studies confirmed that FA-loaded NPs were not toxic according to the MTT colorimetric assay, were able to internalise efficiently SH-SY5Y neuronal cells and supressed the intracellular ROS-level induced by H₂O₂ leading to 52% and 24.7% of cellular viability at 0.082 and 0.041 mg mL^-1, respectively. The permeability of the NPs through the blood brain barrier was tested with an in vitro organ-on-a-chip model to evaluate the ability of the FA-loaded PLGA and non-loaded PLGA NPs to penetrate to the brain. NPs were able to penetrate the barrier, but permeability decreased when FA was loaded. These results are promising for the use of loaded PLGA NPs for the management of neurological diseases.

Characterization and Preliminary In Vitro Antioxidant Activity of a New Multidrug Formulation Based on the Co-Encapsulation of Rutin and the α-Acylamino-β-Lactone NAAA Inhibitor URB894 within PLGA Nanoparticles

A biodegradable and biocompatible polymeric matrix made up of poly(d,l-lactide-co-glycolide) (PLGA) was used for the simultaneous delivery of rutin and the (S)-N-(2-oxo-3-oxetanyl)biphenyl-4-carboxamide derivative (URB894). The goal was to exploit the well-known radical scavenging properties of rutin and the antioxidant features recently reported for the molecules belonging to the class of N-acylethanolamine-hydrolyzing acid amidase (NAAA) inhibitors, such as URB894. The use of the compounds, both as single agents or in association promoted the development of negatively-charged nanosystems characterized by a narrow size distribution and an average diameter of ~200 nm when 0.2-0.6 mg/mL of rutin or URB894 were used. The obtained multidrug carriers evidenced an entrapment efficiency of ~50% and 40% when 0.4 and 0.6 mg/mL of rutin and URB894 were associated during the sample preparation, respectively. The multidrug formulation evidenced an improved in vitro dose-dependent protective effect against H₂O₂-related oxidative stress with respect to that of the nanosystems containing the active compounds as a single agent, confirming the rationale of using the co-encapsulation approach to obtain a novel antioxidant nanomedicine.

Novel Nanotechnology-Driven Prototypes for AI-Enriched Implanted Prosthetics Following Organ Failure

Meeting medical challenges posed by global burdens is proven to be of primary interest. One example is the COVID-19 epidemic that humankind is currently experiencing, since around December 2019. Innovation is key to respond rapidly and effectively to sanitary and health emergencies, when human lives are severely threatened. In this scenery, medical devices that can be rapidly launched in the market and manufactured at scale are crucial for saving lives. One example is a lifesaving respiratory device launched in about 10 days (Mercedes F1 team's new device based on continuous positive airway pressure devices) and rapidly approved by international agencies responsible for assuring drug and medical devices safety, in response to the COVID-19 burden. Remarkably, it is the first time in history that mankind observes disease spread reaching such high proportions, globally, in such short time scale. However, while this epidemic had, in March 2020, reached the critical figures of about 38,000 deaths and c. 738,000 infected, organ donation and transplantation patients are suffering for years, accounting for an increasing number of affected, annually. These patients are invisible for the general public. Therefore, this chapter approaches the organ donation and transplantation burden, proposing effective solutions to leverage the suffering, improving life quality of patients enduring several underlying issues, from hemodialysis complications and critical organ failure to lacking compatible donors. This, on the basis of technology repurposing, to speed up approval processes followed by international agencies responsible for assuring drug and medical devices safety, while adding innovative methods to existing technology and reducing invasiveness.

Modulation of Macrophages Using Nanoformulations with Curcumin to Treat Inflammatory Diseases: A Concise Review

Curcumin (Cur), a traditional Chinese medicine extracted from natural plant rhizomes, has become a candidate drug for the treatment of diseases due to its anti-inflammatory, anticancer, antioxidant, and antibacterial activities. However, the poor water solubility and low bioavailability of Cur limit its therapeutic effects for clinical applications. A variety of nanocarriers have been successfully developed to improve the water solubility, in vivo distribution, and pharmacokinetics of Cur, as well as to enhance the ability of Cur to polarize macrophages and relieve macrophage oxidative stress or anti-apoptosis, thus accelerating the therapeutic effects of Cur on inflammatory diseases. Herein, we review the design and development of diverse Cur nanoformulations in recent years and introduce the biomedical applications and potential therapeutic mechanisms of Cur nanoformulations in common inflammatory diseases, such as arthritis, neurodegenerative diseases, respiratory diseases, and ulcerative colitis, by regulating macrophage behaviors. Finally, the perspectives of the design and preparation of future nanocarriers aimed at efficiently exerting the biological activity of Cur are briefly discussed.

Rosmarinic Acid-Loaded Polymeric Nanoparticles Prepared by Low-Energy Nano-Emulsion Templating: Formulation, Biophysical Characterization, and In Vitro Studies

Rosmarinic acid (RA), a caffeic acid derivative, has been loaded in polymeric nanoparticles made up of poly(lactic-co-glycolic acid) (PLGA) through a nano-emulsion templating process using the phase-inversion composition (PIC) method at room temperature. The obtained RA-loaded nanoparticles (NPs) were colloidally stable exhibiting average diameters in the range of 70–100 nm. RA was entrapped within the PLGA polymeric network with high encapsulation efficiencies and nanoparticles were able to release RA in a rate-controlled manner. A first-order equation model fitted our experimental data and confirmed the prevalence of diffusion mechanisms. Protein corona formation on the surface of NPs was assessed upon incubation with serum proteins. Protein adsorption induced an increase in the hydrodynamic diameter and a slight shift towards more negative surface charges of the NPs. The radical scavenging activity of RA-loaded NPs was also studied using the DPPH·assay and showed a dose–response relationship between the NPs concentration and DPPH inhibition. Finally, RA-loaded NPs did not affect the cellular proliferation of the human neuroblastoma SH-SY5Y cell line and promoted efficient cellular uptake. These results are promising for expanding the use of O/W nano-emulsions in biomedical applications.

Application of curcumin nanoformulations in Alzheimer's disease: prevention, diagnosis and treatment

Objectives: Alzheimer's disease (AD) is a serious neurodegenerative disease. Although many therapeutic strategies have been studied, their clinical applications are immature. Moreover, these methods can only alleviate symptoms rather than cure it, posing a challenge to brain health in older adults worldwide. Curcumin (CUR) is a very promising natural compound for nerve protection and treatment. It can prevent and treat AD, and on the other hand, its fluorescence properties can be used in the diagnosis of AD. However, CUR is characterized by very low water solubility, fluid instability, rapid metabolism, low bioavailability and difficulty in penetrating the biological barriers, which limit its application. Nanocarriers are a potential material to improve the biocompatibility of CUR and its ability to cross biological barriers. Therefore, delivering CUR by nanocarriers is an effective method to achieve better efficacy. Methods: In this review, the preventive, therapeutic and diagnostic effects of CUR nanoformulations on AD, as well as various patents, clinical trials and experimental research progress in this field are discussed. The aim is to provide detailed reference and practical suggestions for future research. Results: CUR has a variety of pharmacological activities in the prevention and treatment of AD, and its nanoformulation can effectively improve solubility, bioavailability and the ability to penetrate the blood-brain barrier. Significant benefits have been observed in the current study. Discussion: CUR formulations have a good prospect in the prevention, diagnosis and treatment of AD, but the safety and principle of its administration need more detailed study in the future.

Effect of curcumin nanoparticles on streptozotocin-induced male Wistar rat model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that afflicts millions of people all over the world. Intracerebroventricular (ICV) injection of a sub-diabetogenic dose of streptozotocin (STZ) was established as an experimental animal model of AD. The present study was conducted to evaluate the efficacy of curcumin nanoparticles (CNs) against the behavioral, neurochemical and histopathological alterations induced by ICV-STZ. The animals were divided into: control animals, the animal model of AD that received a single bilateral ICV microinjection of STZ, and the animals protected by a daily oral administration of CNs for 6 days before the ICV-STZ injection. The animals of all groups were subjected to surgical operation on the 7th day of administration. Then the administration of distilled water or CNs was continued for 8 days. The ICV-STZ microinjection produced cognitive impairment as evident from the behavioral Morris water maze (MWM) test and induced oxidative stress in the cortex and hippocampus as indicated by the significant increases in lipid peroxidation and nitric oxide (NO) levels and the significant decrease in reduced glutathione (GSH) levels. It also produced a significant increase in acetylcholinesterase (AChE) and tumor necrosis-alpha (TNF-ɑ) and a significant decrease in Na+,K + -ATPase. In addition, a significant increase in amino acid neurotransmitters occurred in the hippocampus, whereas a significant decrease was obtained in the cortex of STZ-induced AD rats. CNs ameliorated the behavioral, immunohistochemical and most of the neurochemical alterations induced by STZ in the hippocampus and cortex. It may be concluded that CNs might be considered as a promising therapeutic agent for the treatment of AD.

Nanomedicines, an emerging therapeutic regimen for treatment of ischemic cerebral stroke: A review

Owing to its intricate pathophysiology, cerebral stroke is a serious medical condition caused by interruption or obstruction of blood supply (blockage of vasculature) to the brain tissues which results in diminished supply of essential nutrients and oxygen (hypoxia) and ultimate necrosis of neuronal tissues. A prompt risks assessment and immediate rational therapeutic plan with proficient neuroprotection play critically important role in the effective management of this neuronal emergency. Various conventional medications are being used for treatment of acute ischemic cerebral stroke but fibrinolytic agents, alone or in combination with other agents are considered the mainstay. These clot-busting agents effectively restore blood supply (reperfusion) to ischemic regions of the brain; however, their clinical significance is hampered due to various factors such as short plasma half-life, limited distribution to brain tissues due to the presence of highly efficient physiological barrier, blood brain barrier (BBB), and lacking of target-specific delivery to the ischemic brain regions. To alleviate these issues, various types of nanomedicines such as polymeric nanoparticles (NPs), liposomes, nanoemulsion, micelles and dendrimers have been designed and evaluated. The implication of these newer therapies (nanomedicines) have revolutionized the therapeutic outcomes by improving the plasma half-life, permeation across BBB, efficient distribution to ischemic cerebral tissues and neuroprotection. Furthermore, the adaptation of some diverse techniques including PEGylation, tethering of targeting ligands on the surfaces of nanomedicines, and pH responsive features have also been pondered. The implication of these emerging adaptations have shown remarkable potential in maximizing the targeting efficiency of drugs to ischemic brain tissues, simultaneous delivery of drugs and imaging agents (for early prognosis as well as monitoring of therapy), and therapeutic outcomes such as long-term neuroprotection.

Curcumin Nanoparticles as Promising Therapeutic Agents for Drug Targets

Curcuma longa is very well-known medicinal plant not only in the Asian hemisphere but also known across the globe for its therapeutic and medicinal benefits. The active moiety of Curcuma longa is curcumin and has gained importance in various treatments of various disorders such as antibacterial, antiprotozoal, cancer, obesity, diabetics and wound healing applications. Several techniques had been exploited as reported by researchers for increasing the therapeutic potential and its pharmacological activity. Here, the dictum is the new room for the development of physicochemical, as well as biological, studies for the efficacy in target specificity. Here, we discussed nanoformulation techniques, which lend support to upgrade the characters to the curcumin such as enhancing bioavailability, increasing solubility, modifying metabolisms, and target specificity, prolonged circulation, enhanced permeation. Our manuscript tried to seek the attention of the researcher by framing some solutions of some existing troubleshoots of this bioactive component for enhanced applications and making the formulations feasible at an industrial production scale. This manuscript focuses on recent inventions as well, which can further be implemented at the community level.

Recent advances in nanomedicines for the treatment of ischemic stroke

Ischemic stroke is a cerebrovascular disease normally caused by interrupted blood supply to the brain. Ischemia would initiate the cascade reaction consisted of multiple biochemical events in the damaged areas of the brain, where the ischemic cascade eventually leads to cell death and brain infarction. Extensive researches focusing on different stages of the cascade reaction have been conducted with the aim of curing ischemic stroke. However, traditional treatment methods based on antithrombotic therapy and neuroprotective therapy are greatly limited for their poor safety and treatment efficacy. Nanomedicine provides new possibilities for treating stroke as they could improve the pharmacokinetic behavior of drugs in vivo, achieve effective drug accumulation at the target site, enhance the therapeutic effect and meanwhile reduce the side effect. In this review, we comprehensively describe the pathophysiology of stroke, traditional treatment strategies and emerging nanomedicines, summarize the barriers and methods for transporting nanomedicine to the lesions, and illustrate the latest progress of nanomedicine in treating ischemic stroke, with a view to providing a new feasible path for the treatment of cerebral ischemia.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.

A comprehensive review of the therapeutic potential of curcumin nanoformulations

Today, due to the prevalence of various diseases such as the novel coronavirus (SARS-CoV-2), diabetes, central nervous system diseases, cancer, cardiovascular disorders, and so on, extensive studies have been conducted on therapeutic properties of natural and synthetic agents. A literature review on herbal medicine and commercial products in the global market showed that curcumin (Cur) has many therapeutic benefits compared to other natural ingredients. Despite the unique properties of Cur, its use in clinical trials is very limited. The poor biopharmaceutical properties of Cur such as short half-life in plasma, low bioavailability, poor absorption, rapid metabolism, very low solubility (at acidic and physiological pH), and the chemical instability in body fluids are major concerns associated with the clinical applications of Cur. Recently, nanoformulations are emerging as approaches to develop and improve the therapeutic efficacy of various drugs. Many studies have shown that Cur nanoformulations have tremendous therapeutic potential against various diseases such as SARS-CoV-2, cancer, inflammatory, osteoporosis, and so on. These nanoformulations can inhibit many diseases through several cellular and molecular mechanisms. However, successful long-term clinical results are required to confirm their safety and clinical efficacy. The present review aims to update and explain the therapeutic potential of Cur nanoformulations.

A State of the Art of Antioxidant Properties of Curcuminoids in Neurodegenerative Diseases

Neurodegenerative diseases represent a set of pathologies characterized by an irreversible and progressive, and a loss of neuronal cells in specific areas of the brain. Oxidative phosphorylation is a source of energy production by which many cells, such as the neuronal cells, meet their energy needs. Dysregulations of oxidative phosphorylation induce oxidative stress, which plays a key role in the onset of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). To date, for most neurodegenerative diseases, there are no resolute treatments, but only interventions capable of alleviating the symptoms or slowing the course of the disease. Therefore, effective neuroprotection strategies are needed. In recent years, natural products, such as curcuminoids, have been intensively explored and studied for their therapeutic potentials in several neurodegenerative diseases. Curcuminoids are, nutraceutical compouns, that owen several therapeutic properties such as anti-oxidant, anti-inflammatory and neuroprotective effects. In this context, the aim of this review was to provide an overview of preclinical and clinical evidence aimed to illustrate the antioxidant effects of curcuminoids in neurodegenerative diseases. Promising results from preclinical studies encourage the use of curcuminoids for neurodegeneration prevention and treatment.

Emerging paradigms in treating cerebral infarction with nanotheranostics: opportunities and clinical challenges

Interest is increasing in the use of nanotheranostics as diagnosis, imaging and therapeutic tools for stroke management, but movement to the clinic remains challenging.

Nanotechnology to improve the Alzheimer's disease therapy with natural compounds

Alzheimer's disease (AD) is a form of dementia with high impact worldwide, accounting with more than 46 million cases. It is estimated that the number of patients will be four times higher in 2050. The initial symptoms of AD are almost imperceptible and typically involve lapses of memory in recent events. However, the available medicines still focus on controlling the symptoms and do not cure the disease. Regarding the advances in the discovery of new treatments for this devastating disease, natural compounds are gaining increasing relevance in the treatment of AD. Nevertheless, they present some limiting characteristics such as the low bioavailability and the low ability to cross the blood-brain barrier (BBB) that hinder the development of effective therapies. To overcome these issues, the delivery of natural products by targeting nanocarriers has aroused a great interest, improving the therapeutic activity of these molecules. In this article, a review of the research progress on drug delivery systems (DDS) to improve the therapeutic activity of natural compounds with neuroprotective effects for AD is presented. Graphical abstract.

New Strategy for Reducing Tau Aggregation Cytologically by A Hairpinlike Molecular Inhibitor, Tannic Acid Encapsulated in Liposome

Inhibition of Tau protein aggregation is an attractive therapeutic target for Alzheimer's disease. However, most of the inhibitors have failed in clinical trials due to the superficial understanding of inhibition mechanism and drug-transfer pharmacokinetics. Innovation of design strategy has become a top priority. To afford a hairpinlike molecular inhibitor, we introduced tannic acid, a multibranched polyphenol molecule, and its moiety, gallic acid. We showed that tannic acid could effectively inhibit Tau aggregation through a multidentate chelation mode. We then encapsulated tannic acid in a non-neurotoxic liposome by lecithin/β-sitosterol, overcoating with Tween 80. Using transwell devices, we cytologically demonstrated that tannic acid liposome can successfully be transferred across the model of a blood-brain barrier made up of mouse brain microvascular endothelial cell bEnd.3 and effectively reduce Tau aggregation induced by fibrils of Tau peptide R3 in human neuroblastoma cell SK-N-SH. This result indicates the potential therapeutic effect of tannic acid liposome on Alzheimer's disease.

Transport of PEGylated-PLA nanoparticles across a blood brain barrier model, entry into neuronal cells and in vivo brain bioavailability

Treatments of neurodegenerative diseases (NDDs) are severely hampered by the presence of the blood-brain barrier (BBB) precluding efficient brain drug delivery. The development of drug nanocarriers aims at increasing the brain therapeutic index would represent a real progress in brain disease management. PEGylated polyester nanoparticles (NPs) are intensively tested in clinical trials for improved drug delivery. Our working hypothesis was that some surface parameters and size of NPs could favor their penetration across the BBB and their neuronal uptake. Polymeric material PEG-b-PLA diblocks were synthesized by ring opening polymerisation (ROP) with PEG₂₀₀₀ or PEG₅₀₀₀. A library of polymeric PEG-b-PLA diblocks NPs with different physicochemical properties was produced. The toxicity, endocytosis and transcytosis through the brain microvascular endothelial cells were monitored as well as the neuronal cells uptake. In vitro results lead to the identification of favourable surface parameters for the NPs endocytosis into vascular endothelial cells. NPs endocytosis took place mainly by macropinocytosis while transcytosis was partially controlled by their surface chemistry and size. In vivo assays on a zebrafish model showed that the kinetic of NPs in circulation is dependent on PEG coating properties. In vivo findings also showed a low but similar translocation of PEG-b-PLA diblocks NPs to the CNS, regardless of their properties. In conclusion, modulation of surface PEG chain length and NPs size impact the endocytosis rate of NPs but have little influence on cell barriers translocation; while in vivo biodistribution is influenced by surface PEG chain density.

Ascorbyl-dipalmitate-stabilised nanoemulsions as a potential localised treatment of inflammatory bowel diseases

Current efforts on inflammatory bowel diseases (IBD) treatment are focused on strategies for localised drug delivery at the intestinal mucosa. Despite the potential of curcumin (CC) for IBD treatment, its low solubility and stability limit its application. Thus, the design of nanocarriers that focus CC delivery at the intestinal epithelium is an area of interest. This work proposes α-tocopherol nanoemulsions (NE) stabilised by ascorbyl-2,6-dipalmitate (ADP) as intestinal CC-carriers. The antioxidant capacity of α-tocopherol and ADP could have a synergistic effect on IBD-affected tissues, characterised by an oxidative environment. We obtained nanoemulsions (NE-ADP) with size below 200 nm, negative surface charge, stable in gastrointestinal media and no toxic in the Caco-2 cell model. Intracellular retention of NE-ADP in Caco-2 cells was observed by confocal microscopy. The extremely low P_app values obtained for CC and α-tocopherol indicated the lack of transport across the Caco-2 monolayer. Control nanoemulsion stabilised by lecithin (NE-L) was greatly transported across the Caco-2 cells monolayer, confirming the relevance of ADP on the cellular retention of NE-ADP. The therapeutic potential of NE-ADP was shown by the significant decrease of intracellular ROS levels. Altogether, these results indicate the potential of NE-ADP as a novel approach for the treatment of IBD.

Curcumin's Nanomedicine Formulations for Therapeutic Application in Neurological Diseases

The brain is the body's control center, so when a disease affects it, the outcomes are devastating. Alzheimer's and Parkinson's disease, and multiple sclerosis are brain diseases that cause a large number of human deaths worldwide. Curcumin has demonstrated beneficial effects on brain health through several mechanisms such as antioxidant, amyloid β-binding, anti-inflammatory, tau inhibition, metal chelation, neurogenesis activity, and synaptogenesis promotion. The therapeutic limitation of curcumin is its bioavailability, and to address this problem, new nanoformulations are being developed. The present review aims to summarize the general bioactivity of curcumin in neurological disorders, how functional molecules are extracted, and the different types of nanoformulations available.

Antioxidants and Nanotechnology: Promises and Limits of Potentially Disruptive Approaches in the Treatment of Central Nervous System Diseases

Many central nervous system (CNS) diseases are still incurable and only symptomatic treatments are available. Oxidative stress is suggested to be a common hallmark, being able to cause and exacerbate the neuronal cell dysfunctions at the basis of these pathologies, such as mitochondrial impairments, accumulation of misfolded proteins, cell membrane damages, and apoptosis induction. Several antioxidant compounds are tested as potential countermeasures for CNS disorders, but their efficacy is often hindered by the loss of antioxidant properties due to enzymatic degradation, low bioavailability, poor water solubility, and insufficient blood-brain barrier crossing efficiency. To overcome the limitations of antioxidant molecules, exploitation of nanostructures, either for their delivery or with inherent antioxidant properties, is proposed. In this review, after a brief discussion concerning the role of the blood-brain barrier in the CNS and the involvement of oxidative stress in some neurodegenerative diseases, the most interesting research concerning the use of nano-antioxidants is introduced and discussed, focusing on the synthesis procedures, functionalization strategies, in vitro and in vivo tests, and on recent clinical trials.

A review on biological activities of Schiff base, hydrazone, and oxime derivatives of curcumin

Schiff base, hydrazone, and oxime derivatives of curcumin showed enhanced biological activities.

Curcumin-loaded nanoparticles: a novel therapeutic strategy in treatment of central nervous system disorders

Curcumin as a hydrophobic polyphenol is extracted from the rhizome of Curcuma longa. Curcumin is widely used as a dietary spice and a topical medication for the treatment of inflammatory disorders in Asia. This compound also possesses remarkable anti-inflammatory and neuroprotective effects with the ability to pass from the blood brain barrier. Based on several pharmacological activities of curcumin, it has been introduced as an ideal candidate for different neurological disorders. Despite the pleiotropic activities of curcumin, poor solubility, rapid clearance and low stability have limited its clinical application. In recent years, nano-based drug delivery system has effectively improved the aqueous solubility and bioavailability of curcumin. In this review article, the effects of curcumin nanoparticles and their possible mechanism/s of action has been elucidated in various central nervous system (CNS)-related diseases including Parkinson's disease, Huntington disease, Alzheimer's disease, Multiple sclerosis, epilepsy and Amyotrophic Lateral Sclerosis. Furthermore, recent evidences about administration of nano-curcumin in the clinical trial phase have been described in the present review article.

Natural Compounds for Alzheimer's Disease Therapy: A Systematic Review of Preclinical and Clinical Studies

Alzheimer's Disease (AD) is a neurodegenerative disorder related with the increase of age and it is the main cause of dementia in the world. AD affects cognitive functions, such as memory, with an intensity that leads to several functional losses. The continuous increase of AD incidence demands for an urgent development of effective therapeutic strategies. Despite the extensive research on this disease, only a few drugs able to delay the progression of the disease are currently available. In the last years, several compounds with pharmacological activities isolated from plants, animals and microorganisms, revealed to have beneficial effects for the treatment of AD, targeting different pathological mechanisms. Thus, a wide range of natural compounds may play a relevant role in the prevention of AD and have proven to be efficient in different preclinical and clinical studies. This work aims to review the natural compounds that until this date were described as having significant benefits for this neurological disease, focusing on studies that present clinical trials.

Determination and pharmacokinetic study of isothiouronium-modified pyrimidine-substituted curcumin analog (1G), a novel antitumor agent, in rat plasma by liquid chromatography-tandem mass spectrometry

1G, a novel derivative of curcumin, exhibits promising anticancer activities in various cancer cell lines. To support its further pharmacological studies, a liquid chromatography-tandem mass spectrometry method was developed and validated in accordance with FDA's Guidance. After extraction by protein precipitation, analytes were separated by a 4.5 min gradient elution (water/0.1% formic acid and methanol) on a reverse-phase C₁₈ column at 40 °C. The multiple reaction monitoring mode was used for quantification on a triple quadrupole mass spectrometer with positive ionization. The assay was linear over the concentration range of 5-1000 ng/mL with a correlation coefficient (r) greater than 0.99. Values of intra- and inter-day precision and accuracy were satisfactory, i.e. <10.1% for precision and within ± 14.5% for accuracy. No obvious matrix effect was observed. Recovery of the analyte was higher than 95.3%. 1G was stable during the whole analytic process. The validated method was successfully applied to the pharmacokinetic study of 1G after intravenous and intraperitoneal administration in rats. Favorable pharmacokinetic profiles were demonstrated, including good abdominal absorption (F = 62.58%), moderate clearance and high extravascular distribution. Results indicated that as a novel antitumor agent, 1G exhibited acceptable pharmacokinetic properties for further in vivo pharmacologic evaluation.

Formulations of Curcumin Nanoparticles for Brain Diseases

Curcumin is a polyphenol that is obtained from Curcuma longa and used in various areas, such as food and textiles. Curcumin has important anti-inflammatory and antioxidant properties that allow it to be applied as treatment for several emerging pathologies. Remarkably, there are an elevated number of publications deriving from the terms "curcumin" and "curcumin brain diseases", which highlights the increasing impact of this polyphenol and the high number of study groups investigating their therapeutic actions. However, its lack of solubility in aqueous media, as well as its poor bioavailability in biological systems, represent limiting factors for its successful application. In this review article, the analysis of its chemical composition and the pivotal mechanisms for brain applications are addressed in a global manner. Furthermore, we emphasize the use of nanoparticles with curcumin and the benefits that have been reached as an example of the extensive advances in this area of health.

Nanoparticle-conjugated nutraceuticals exert prospectively palliative of amyloid aggregation

Alzheimer's disease (AD), an age-related neurodegenerative disease, the most common causes of dementia is a multifactorial pathology categorized by a complex etiology. Numerous nutraceuticals have been clinically evaluated, but some of the trials failed. However, natural compounds have some limitations due to their poor bioavailability, ineffective capability to cross the blood-brain barrier, or less therapeutic effects on AD. To overcome these disadvantages, nanoparticle-conjugated natural products could promote the bioavailability and enhance the therapeutic efficacy of AD when compared with a naked drug. This application generates and implements new prospect for drug discovery in neurodegenerative diseases. In this article, we confer AD pathology, review natural products in clinical trials, and ascertain the importance of nanomedicine coupled with natural compounds for AD.

Amphiphilic Nanocarrier Systems for Curcumin Delivery in Neurodegenerative Disorders

Neurodegenerative diseases have become a major challenge for public health because of their incurable status. Soft nanotechnology provides potential for slowing down the progression of neurodegenerative disorders by using innovative formulations of neuroprotective antioxidants like curcumin, resveratrol, vitamin E, rosmarinic acid, 7,8-dihydroxyflavone, coenzyme Q10, and fish oil. Curcumin is a natural, liposoluble compound, which is of considerable interest for nanomedicine development in combination therapies. The neuroprotective effects of combination treatments can involve restorative mechanisms against oxidative stress, mitochondrial dysfunction, inflammation, and protein aggregation. Despite the anti-amyloid and anti-tau potential of curcumin and its neurogenesis-stimulating properties, the utilization of this antioxidant as a drug in neuroregenerative therapies has huge limitations due to its poor water solubility, physico-chemical instability, and low oral bioavailability. We highlight the developments of soft lipid- and polymer-based delivery carriers of curcumin, which help improve the drug solubility and stability. We specifically focus on amphiphilic liquid crystalline nanocarriers (cubosome, hexosome, spongosome, and liposome particles) for the encapsulation of curcumin with the purpose of halting the progressive neuronal loss in Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis (ALS).

Neuro-protective role of nanocapsulated curcumin against cerebral ischemia-reperfusion induced oxidative injury

Cerebral ischemia-reperfusion (CIR) accelerates the progression of neurodegeneration by causing mitochondrial dysfunction to overproduce reactive oxygen species (ROS). Curcumin shows protective effects against CIR-induced oxidative damage. Free curcumin (FC) is effective at high doses due to its poor bioavailability. Also the blood-brain barrier (BBB) limits the passage of substances from circulation into the cerebral region. Thus, formulation of curcumin within polyethylene glycol (PEG)-ylated polylactide-co-glycolide (PLGA) nanoparticles (NC) was applied orally to aged rats to explore its role against CIR injury. Mitochondrial damage was evaluated. The levels of pro-inflammatory cytokines and components of apoptotic pathway were studied. Unlike FC, NC pre-treatment exerted better neuro-protection by ameliorating ROS-mediated oxidative damage and prevented CIR-induced neuronal apoptosis. Therefore, curcumin incorporated PEGylated PLGA nanoparticles may be used as a suitable delivery vehicle to the brain as they can increase curcumin bioavalability and the released curcumin may confer protection to the neurons against CIR-induced oxidative damage.

In Vitro Modulation of TrkB Receptor Signaling upon Sequential Delivery of Curcumin-DHA Loaded Carriers Towards Promoting Neuronal Survival

PURPOSE

To in vitro investigate the capacity of carrier-free and lipid-nanoparticle (NP)-encapsulated phytochemical compounds to prevent neuronal damage through neurotrophin potentiating activities. Delivery of molecules promoting the neurotrophin receptor signaling in the central nervous system (CNS) present ongoing interest for combination therapy development.

METHODS

Super-resolution Stimulated Emission Depletion (STED) microscopy imaging and flow cytometry analysis were employed to study the expression of the neurotrophin TrkB receptor in a neuronal cell model, which is highly responsive to binding of brain-derived neurotrophic factor (BDNF). Dual drug-loaded nanoparticle formulations, prepared by self-assembly of lyotropic lipids and PEGylated amphiphile derivatives, were delivered to differentiated human neuroblastoma SH-SY5Y cells subjected to degenerative conditions.

RESULTS

The expression of BDNF in the intra and extracellular domains was quantified by ELISA and flow cytometry after sequential treatment of the degenerating SH-SY5Y cells by neurotherapeutic formulations. Flow cytometry was also used to assess the phosphorylation of the transcription factor cAMP response element-binding protein (CREB) in the intracellular domain as a result of the treatment by nanoformulations.

CONCLUSION

Over time, dual drug formulations (curcumin and docosahexaenoic acid (DHA)) promoted the neuronal survival and repair processes through enhanced BDNF secretion and increased phosphorylation of CREB as compared to untreated degenerating cells.

Optimization of Curcumin-Loaded PEG-PLGA Nanoparticles by GSH Functionalization: Investigation of the Internalization Pathway in Neuronal Cells

One major challenge in the field of nanotherapeutics is to increase the selective delivery of cargo to targeted cells. Using polylactic-co-glycolic acid (PLGA), we recently highlighted the importance of polymer composition in the biological fate of the nanodrug delivery systems. However, the route of internalization of polymeric nanoparticles (NPs) is another key component to consider in the elaboration of modern and targeted devices. For that purpose, herein, we effectively synthesized and characterized glutathione-functionalized PLGA-nanoparticles (GSH-NPs) loaded with curcumin (GSH-NPs-Cur), using thiol-maleimide click reaction and determined their physicochemical properties. We found that GSH functionalization did not affect the drug loading efficiency (DLE), the size, the polydispersity index (PDI), the zeta potential, the release profile, and the stability of the formulation. While being nontoxic, the presence of GSH on the surface of the formulations exhibits a better neuroprotective property against acrolein. The neuronal internalization of GSH-NPs-Cur was higher than free curcumin. In order to track the intracellular localization of the formulations, we used a covalently attached rhodamine (PLGA-Rhod), into our GSH-functionalized matrix. We found that GSH-functionalized matrix could easily be taken up by neuronal cells. Furthermore, we found that GSH conjugation modifies the route of internalization enabling them to escape the uptake through macropinocytosis and therefore avoiding the lysosomal degradation. Taken together, GSH functionalization increases the uptake of formulations and modifies the route of internalization toward a safer pathway. This study shows that the choice of ideal ligand to develop NPs-targeting devices is a crucial step when designing innovative strategy for neuronal cells delivery.

Discovery of a new function of curcumin which enhances its anticancer therapeutic potency

Curcumin has received immense attention over the past decades because of its diverse biological activities and recognized as a promising drug candidate in a large number of diseases. However, its clinical application has been hindered due to extremely low aqueous solubility, chemical stability, and cellular uptake. In this study, we discovered quite a new function of curcumin, i.e. pH-responsive endosomal disrupting activity, derived from curcumin's self-assembly. We selected anticancer activity as an example of biological activities of curcumin, and investigated the contribution of pH-responsive property to its anticancer activity. As a result, we demonstrated that the pH-responsive property significantly enhances the anticancer activity of curcumin. Furthermore, we demonstrated a utility of the pH-responsive property of curcumin as delivery nanocarriers for doxorubicin toward combination cancer therapy. These results clearly indicate that the smart curcumin assemblies act as promising nanoplatform for development of curcumin-based therapeutics.