Protective Effect of Natural Antioxidant, Curcumin Nanoparticles, and Zinc Oxide Nanoparticles against Type 2 Diabetes-Promoted Hippocampal Neurotoxicity in Rats

Relationship of Curcumin with Aging and Alzheimer and Parkinson Disease, the Most Prevalent Age-Related Neurodegenerative Diseases: A Narrative Review

The elderly population is increasing worldwide every day. Age is a significant factor in the progression of neurological diseases, which can also cause cognitive decline and memory disorders. Inflammation and oxidative stress are primary drivers of senescence and disorders, particularly those associated with aging and neurodegenerative diseases. Bioactive phytochemicals are considered a promising therapeutic strategy in combating aging and age-related pathological conditions. One of the phytochemicals with diverse biological properties encompassing antioxidant, anti-inflammatory, antibacterial, antiviral, anticancer, antifungal, antidepressant, anti-allergic, and anti-aging properties is curcumin. Curcumin, a polyphenolic structure with a distinct orange hue and unique chemical properties, is derived from the roots of Curcuma longa, a member of the Zingiberaceae family, commonly known as turmeric. It has been noted that the incidence of neurodegenerative diseases is low in societies that consume curcumin widely. Therefore, this review investigates the effect of curcumin on aging and Alzheimer and Parkinson disease, which are the most prevalent age-related neurodegenerative diseases.

Role of curcumin on beta-amyloid protein, tau protein, and biochemical and oxidative changes in streptozotocin-induced diabetic rats

Diabetes is one of the most common endocrine metabolic diseases and is associated with the accumulation of beta-amyloid plaques in the brain. Amyloid beta (Aβ) and abnormal tau proteins are effective in the development of Alzheimer's disease. The aim of this study is to investigate the therapeutic and protective effects of curcumin on beta-amyloid (Aβ) accumulation and tau protein expression levels, as well as biochemical and oxidative changes in streptozotocin-induced diabetes in rats. The study comprised five groups, each consisting of eight rats: control, diabetic, curcumin, curcumin during diabetic induction, and curcumin post-diabetic induction. Groups 2 and 4 were administered a single dose of 45 mg/kg streptozotocin on day 1, while group 5 received it on day 28. Curcumin was orally administered via gavage at a dose of 100 mg/kg/day for 35 days to the third, fourth, and fifth groups. At the end of the trial (day 35), blood sugar levels and insulin resistance were similar between the control and curcumin-treated groups but significantly higher in the diabetic groups (P < 0.05). The protective effect of curcumin is tested during induction and active diabetes. The results indicated that diabetic rats displayed increased levels of Aβ, tau protein, and total oxidant capacity (TOS) compared to the curcumin-treated groups. Additionally, the total antioxidant capacity (TAS) levels were lower in the diabetic rats (P < 0.05). Aβ protein levels are lower in both the serum and brain of rats with active diabetes and treated with curcumin compared to control rats (P > 0.05). In addition, serum TAS levels were higher in rats treated with curcumin following the induction of diabetes than pre-induction of diabetes (P > 0.05). The TOS levels in the serum were higher in the rats treated with curcumin during active diabetes compared to the rats treated prior to the induction of diabetes (P < 0.05). However, no significant difference was observed in the brain. The above results show that curcumin has an effect on reducing oxidative stress caused by diabetes and increasing antioxidant activity.

Enhancing the bioavailability and activity of natural antioxidants with nanobubbles and nanoparticles

KEY POLICY HIGHLIGHTSNanobubbles and nanoparticles may enhance the polyphenols' bioavailabilityNanobubbles may stimulate the activation of Nrf2 and detox enzymesArmoured oxygen nanobubbles may enhance radiotherapy or chemotherapy effects.

Alleviative effects of green-fabricated zinc oxide nanoparticles on acrylamide-induced oxidative and inflammatory reactions in the rat stomach via modulating gastric neuroactive substances and the MiR-27a-5p/ROS/NF-κB axis

Little is known about the effects of acrylamide (AMD) on the stomach. So, this study evaluated the effect of oral AMD exposure (20 mg/kg b.wt) on oxidative status, apoptotic, and inflammatory reactions in rat's stomach for 60 days. To explore novel targets of AMD toxicity, a more detailed molecular and immune-expression study was performed. Besides, the possible protective effect of green synthesized zinc oxide nanoparticles (G-ZNP) (10 mg/kg b.wt) was explored. The results revealed that AMD significantly provoked oxidative and lipid peroxidative damage of the stomach in terms of increased ROS and MDA but reduced SOD, CAT, GSH, and GSH/GSSG. Additionally, the stomachs of AMD-exposed rats showed a significant increment of PGE2 but reduced NO. Histopathologically, AMD induced a significant increase in PAS stain and the immunoexpression of iNOS and NF-κB in the glandular stomach. A significant upregulation of CART, VACHT, EGFR, caspase-3, NOS-1, and miR-27a-5p was evident in the stomach of the AMD group. Yet, G-ZNP oral dosing significantly rescued the AMD-induced oxidative damage, apoptotic reaction, inflammatory effect, and altered miR-27a-5p and gene expressions in the stomach. Conclusively, these findings demonstrated the efficacy of G-ZNP in protecting against the harmful impacts of acrylamide on stomach tissues.

Neuroprotective properties of zinc oxide nanoparticles: therapeutic implications for Parkinson's disease

Parkinson's disease (PD) significantly affects millions of people worldwide due to the progressive degeneration of dopamine-producing neurons in the substantia nigra pars compacta. Despite extensive research efforts, effective treatments that can halt or reverse the progression of PD remain elusive. In recent years, nanotechnology has emerged as a promising new avenue for addressing this challenge, with zinc oxide nanoparticles (ZnO-NPs) standing out for their extensive therapeutic potential. ZnO-NPs have shown remarkable promise in neuroprotection through several key mechanisms. The multifaceted properties of ZnO-NPs suggest that they could play a crucial role in intervening across various fundamental mechanisms implicated in PD. By targeting these mechanisms, ZnO-NPs offer new insights and potential strategies for managing and treating PD. This review aims to provide a thorough examination of the molecular mechanisms through which ZnO-NPs exert their neuroprotective effects. It highlights their potential as innovative therapeutic agents for PD and outlines directions for future research to explore and harness their full capabilities.

Examining the Influence of Zinc Oxide Nanoparticles and Bulk Zinc Oxide on Rat Brain Functions: a Comprehensive Neurobehavioral, Antioxidant, Gene Expression, and Histopathological Investigation

The study aimed to assess the impact of zinc oxide nanoparticles (ZnONPs) on rats' neurobehavior compared to bulk zinc oxide (BZnO). Thirty male Sprague-Dawley rats were randomly assigned to five groups. The control group received Tween 80 (10%), while the ZnONP groups were given ZnONPs at 5 and 10 mg/kg body weight dosages, and the bulk zinc oxide (BZnO) groups received BZnO at the same dosages. Behavioral observations, neurobehavioral examinations, and assessments of brain tissue oxidative markers, neurotransmitter levels, and histopathological changes were performed. The results indicated that ZnONP at a dosage of 5 mg/kg improved general behavior, locomotor activity, memory, and recognition and reduced fearfulness in rats. Conversely, the higher dosage of 10 mg/kg and the bulk form had adverse effects on general behavior, locomotor activity, and learning ability, with the bulk form demonstrating the most severe impact-znONP-5 treatment increased antioxidant enzyme levels and decreased inflammatory markers. BZnO-5 exhibited lower oxidative stress markers, although still higher than BZnO-10. Furthermore, ZnONP-5 and BZnO-5 increased neurotransmitter levels compared to higher dosages. ZnONP-5 upregulated the expression of brain-derived neurotrophic factor (BDNF) mRNA, while BZnO-5 showed increased BDNF mRNA expression and decreased expression of genes related to apoptosis and inflammation. In summary, ZnONPs at 5 mg/kg demonstrated positive effects on rat brain function and behavior, while higher dosages and the bulk form had detrimental effects. In conclusion, the studies emphasized the importance of further assessing various doses and forms of zinc oxide on brain health, highlighting the significance of dosage considerations when using nanomaterials.

Breaking Barriers in Alzheimer's Disease: the Role of Advanced Drug Delivery Systems

Alzheimer's disease (AD), characterized by cognitive impairment, brain plaques, and tangles, is a global health concern affecting millions. It involves the build-up of amyloid-β (Aβ) and tau proteins, the formation of neuritic plaques and neurofibrillary tangles, cholinergic system dysfunction, genetic variations, and mitochondrial dysfunction. Various signaling pathways and metabolic processes are implicated in AD, along with numerous biomarkers used for diagnosis, risk assessment, and research. Despite these, there is no cure or effective treatment for AD. It is critically important to address this immediately to develop novel drug delivery systems (NDDS) capable of targeting the brain and delivering therapeutic agents to modulate the pathological processes of AD. This review summarizes AD, its pathogenesis, related signaling pathways, biomarkers, conventional treatments, the need for NDDS, and their application in AD treatment. It also covers preclinical, clinical, and ongoing trials, patents, and marketed AD formulations.

Neuroprotective effects of L-Dopa-modified zinc oxide nanoparticles on the rat model of 6-OHDA-ınduced Parkinson's disease

Parkinson's disease (PD) is a chronic neurodegenerative case. As the disease progresses, the response time to doses of levodopa (L-Dopa) becomes shorter and the effects of the drug are severely limited by some undesirable side effects such as the 'on-off' phenomenon. In several diseases, including Parkinson's, nanoparticles can deliver antioxidant compounds that reduce oxidative stress. This study evaluates and compares the neuroprotective effects of L-Dopa-modified zinc nanoparticles (ZnNPs) in the 6-hydroxydopamine (6-OHDA)-induced PD rat model. For this purpose, the synthesis of NPs was carried out. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectrophotometer were used for characterization. The rats were randomized into 9 experimental groups: control, lesion group (6-OHDA), 6-OHDA + 5 mg/kg L-Dopa, 6-OHDA + 10 mg/kg L-Dopa, 6-OHDA + 20 mg/kg L-Dopa, 6-OHDA + 20 mg/kg ZnNPs, 6-OHDA + 40 mg/kg ZnNPs, 6-OHDA + 30 mg/kg ZnNPs + L-Dopa, and 6-OHDA + 60 mg/kg ZnNPs + L-Dopa. Behavioral tests were performed on all groups 14 days after treatment. Phosphatase and tensin homolog, Excitatory amino acid transporter 1/2, and Glutamine synthetase gene analyses were performed on brain samples taken immediately after the tests. In addition, histological and immunohistochemical methods were used to determine the general structure and properties of the tissues. We obtained important findings that L-Dopa-modified ZnNPs increased the activity of glutamate transporters. Our experiment showed that glutamate increases neuronal cell vitality and improves behavioral performance. Therefore, L-Dopa-modified ZnNPs can be used to prevent neurotoxicity. According to what we found, results show that L-Dopa-modified ZnNPs will lend to the effective avoidance and therapy of PD.

Selenium Nanoparticles as Neuroprotective Agents: Insights into Molecular Mechanisms for Parkinson's Disease Treatment

Oxidative stress and the accumulation of misfolded proteins in the brain are the main causes of Parkinson's disease (PD). Several nanoparticles have been used as therapeutics for PD. Despite their therapeutic potential, these nanoparticles induce multiple stresses upon entry. Selenium (Se), an essential nutrient in the human body, helps in DNA formation, stress control, and cell protection from damage and infections. It can also regulate thyroid hormone metabolism, reduce brain damage, boost immunity, and promote reproductive health. Selenium nanoparticles (Se-NPs), a bioactive substance, have been employed as treatments in several disciplines, particularly as antioxidants. Se-NP, whether functionalized or not, can protect mitochondria by enhancing levels of reactive oxygen species (ROS) scavenging enzymes in the brain. They can also promote dopamine synthesis. By inhibiting the aggregation of tau, α-synuclein, and/or Aβ, they can reduce the cellular toxicities. The ability of the blood-brain barrier to absorb Se-NPs which maintain a healthy microenvironment is essential for brain homeostasis. This review focuses on stress-induced neurodegeneration and its critical control using Se-NP. Due to its ability to inhibit cellular stress and the pathophysiologies of PD, Se-NP is a promising neuroprotector with its anti-inflammatory, non-toxic, and antimicrobial properties.

Curcumin nanogel and its efficacy against oxidative stress and inflammation in rat models of ischemic stroke

Aim: The study was designed to develop and analyze curcumin nanoparticles. Methods: Curcumin nanoparticles were formulated and evaluated. Their efficacy in protecting against brain damage was investigated in a rat model of ischemic stroke, considering motor function, muscle strength and antioxidant enzyme activity. Results: Curcumin nanoparticles displayed a zeta potential of -55 ± 13.5 mV and an average particle size of 51.40 ± 21.70 nm. In ischemic stroke rat models, curcumin nanoparticle treatment significantly improved motor functions, and muscle strength and increased the activities of antioxidant enzymes like glutathione peroxidase, glutathione, glutathione S-transferase, superoxide dismutase and catalase, reducing oxidative stress and inflammation. Conclusion: Curcumin nanoparticles showed significant neuroprotective effects in ischemic stroke models.

The synergistic effect of nanocurcumin and donepezil on Alzheimer's via PI3K/AKT/GSK-3β pathway modulating

Alzheimer's disease (AD) hallmarks include amyloid-βeta (Aβ) and tau proteins aggregates, neurite degeneration, microglial activation with cognitive impairment. Phosphatidylinositol-3-kinase/protein kinase B/Glycogen synthase kinase-3-beta (PI3K/AKT/GSK-3) pathway is essential for neuroprotection, cell survival and proliferation by blocking apoptosis. This study aimed to assess protective role of nanocurcumin (NCMN) as strong antioxidant and anti-inflammatory agent with elucidating its synergistic effects with Donepezil as acetylcholinesterase inhibitor on AD in rats via modulating PI3K/AKT/GSK-3β pathway. The experiment was performed on 70 male Wistar albino rats divided into seven groups (control, NCMN, Donepezil, AD-model, Donepezil co-treatment, NCMN only co-treatment, and NCMN+Donepezil combined treatment). Behavioral and biochemical investigations as cholinesterase activity, oxidative stress (malondialdehyde, reduced glutathione, nitric oxide, superoxidedismutase, and catalase), tumor necrosis factor-alpha, Tau, β-site amyloid precursor protein cleaving enzyme-1 (BACE-1), Phosphatase and tensin homolog (Pten), mitogen-activated protein kinase-1 (MAPK-1), Glycogen synthase kinase-3-beta (GSK-3β) and toll-like receptor-4 were evaluated. Treatment with NCMN improved memory, locomotion, neuronal differentiation by activating PI3K/AKT/GSK-3β pathway. These results were confirmed by histological studies in hippocampus.

Curcumin, its derivatives, and their nanoformulations: Revolutionizing cancer treatment

Curcumin is a natural compound derived from turmeric and can target malignant tumor molecules involved in cancer propagation. It has potent antioxidant activity, but its effectiveness is limited due to poor absorption and rapid elimination from the body. Various curcumin derivatives have also shown anticancer potential in in-vitro and in-vivo models. Curcumin can target multiple signaling pathways involved in cancer development/progression or induce cancer cell death through apoptosis. In addition, curcumin and its derivatives could also enhance the effectiveness of conventional chemotherapy, radiation therapy and reduce their associated side effects. Lately, nanoparticle-based delivery systems are being developed/explored to overcome the challenges associated with curcumin's delivery, increasing its overall efficacy. The use of an imaging system to track these formulations could also give beneficial information about the bioavailability and distribution of the nano-curcumin complex. In conclusion, curcumin holds significant promise in the fight against cancer, especially in its nanoform, and could provide precise delivery to cancer cells without affecting normal healthy cells.

Curcumin- β-Cyclodextrin Molecular Inclusion Complex: A Water-Soluble Complex in Fast-dissolving Tablets for the Treatment ofNeurodegenerative Disorders

BACKGROUND

Orally disintegrating tablets (ODTs) have become an excellent choice for delivering drugs as their palatability is greatly improved. In this work, β-cyclodextrin has been used to improve the solubility of curcumin by encapsulating it into the hydrophobic cavity for the treatment of neurodegenerative disorders.

OBJECTIVES

The current study aimed to present the design, formulation, and optimisation of fastdissolving oral tablets of curcumin- β-cyclodextrin molecular inclusion complex using a 32-factorial design.

METHODS

The drug-excipient compatibility was studied by FTIR spectroscopy. The inclusion complex of curcumin-β-cyclodextrin was prepared using solvent casting and confirmed using XRD studies. Powder blends were evaluated for flow properties. Tablets prepared by direct compression were evaluated for post-compression parameters. Further, the effect of formulation variables, such as sodium starch glycolate (X1) and Neusilin® ULF2 (X2), on various responses, including disintegration time and dissolution at 2 hours, was studied using statistical models.

RESULTS

Post-compression parameters, i.e., hardness (4.4-5 kg/cm2), thickness (3.82-3.93 mm), weight variation (±7.5%), friability (< 1%), wetting time (51-85 seconds) and drug content (96.28- 99.32%) were all found to be within the permissible limits and the disintegration time of tablets with super-disintegrants ranged between 45-58 seconds. The in-vitro dissolution profile of tablets showed that higher SSG and Neuslin® ULF2 levels promoted drug release. For statistical analysis, the 2FI model was chosen. Optimised variables for formulation have been determined and validated with the experimental findings based on the significant desirability factor.

CONCLUSION

The current study reveals the validated curcumin-β-cyclodextrin inclusion complex fastdissolving tablets with SSG and Neusilin® ULF2 to be an ideal choice for effectively treating neurodegenerative disorders.

Myco-fabricated ZnO nanoparticles ameliorate neurotoxicity in mice model of Alzheimer's disease via acetylcholinesterase inhibition and oxidative stress reduction

Alzheimer's disease (AD) is one of the primary health problems linked to the decrease of acetylcholine in cholinergic neurons and elevation in oxidative stress. Myco-fabrication of ZnO-NPs revealed excellent biological activities, including anti-inflammatory and acetylcholinesterase inhibitory potentials. This study aims to determine if two distinct doses of myco-fabricated ZnO-NPs have a positive impact on behavioral impairment and several biochemical markers associated with inflammation and oxidative stress in mice that have been treated by aluminum chloride (AlCl3) to induce AD. Sixty male mice were haphazardly separated into equally six groups. Group 1 was injected i.p. with 0.5 ml of deionized water daily during the experiment. Mice in group 2 received AlCl3 (50 mg/kg/day i.p.). Groups 3 and 4 were treated i.p. with 5 and 10 mg/kg/day of ZnO-NPs only, respectively. Groups 5 and 6 were given i.p. 5 and 10 mg/kg/day ZnO-NPs, respectively, add to 50 mg/kg/day AlCl3. Results showed that the AlCl3 caused an increase in the escape latency time and a reduction in the time spent in the target quadrant, indicating a decreased improvement in learning and memory. Moreover, acetylcholinesterase enzyme (AChE) activity and malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and interleukin 1β (IL-1β) levels were significantly increased, and the content of glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), as well as levels of serotonin and dopamine, were decreased in brain tissues only in AlCl3 treated mice. However, treatment of mice with myco-fabrication of ZnO-NPs at doses of 5 or 10 mg/kg improves learning and memory function through ameliorate all the previous parameters in the AD mice group. The low dose of 5 mg/kg is more effective than a high dose of 10 mg/kg. In accordance with these findings, myco-fabricated ZnO-NPs could enhance memory and exhibit a protective influence against memory loss caused by AlCl3.

Role of Nanoparticle-Conjugates and Nanotheranostics in Abrogating Oxidative Stress and Ameliorating Neuroinflammation

Oxidative stress is a deteriorating condition that arises due to an imbalance between the reactive oxygen species and the antioxidant system or defense of the body. The key reasons for the development of such conditions are malfunctioning of various cell organelles, such as mitochondria, endoplasmic reticulum, and Golgi complex, as well as physical and mental disturbances. The nervous system has a relatively high utilization of oxygen, thus making it particularly vulnerable to oxidative stress, which eventually leads to neuronal atrophy and death. This advances the development of neuroinflammation and neurodegeneration-associated disorders such as Alzheimer's disease, Parkinson's disease, epilepsy, dementia, and other memory disorders. It is imperative to treat such conditions as early as possible before they worsen and progress to irreversible damage. Oxidative damage can be negated by two mechanisms: improving the cellular defense system or providing exogenous antioxidants. Natural antioxidants can normally handle such oxidative stress, but they have limited efficacy. The valuable features of nanoparticles and/or nanomaterials, in combination with antioxidant features, offer innovative nanotheranostic tools as potential therapeutic modalities. Hence, this review aims to represent novel therapeutic approaches like utilizing nanoparticles with antioxidant properties and nanotheranostics as delivery systems for potential therapeutic applications in various neuroinflammation- and neurodegeneration-associated disease conditions.

Nanoparticles loaded with natural medicines for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that disrupts cognitive function and severely affects the quality of life. Existing drugs only improve cognitive function and provide temporary relief of symptoms but do not stop or delay disease progression. Recently, natural medicines, especially Chinese herbal medicines, have gained attention in the treatment of AD due to their antioxidant, anti-inflammatory, and neuroprotective effects. However, conventional oral dosage forms lack brain specificity and have side effects that lead to poor patient compliance. Utilizing nanomedicine is a promising approach to improve brain specificity, bioavailability, and patient compliance. This review evaluates recent advances in the treatment of AD with nanoparticles containing various natural medicines. This review highlights that nanoparticles containing natural medicines are a promising strategy for the treatment of AD. It is believed that this technology can be translated into the clinic, thereby providing opportunities for AD patients to participate in social activities.

Curcumin, inflammation, and neurological disorders: How are they linked?

Background

Despite the extensive research in recent years, the current treatment modalities for neurological disorders are suboptimal. Curcumin, a polyphenol found in Curcuma genus, has been shown to mitigate the pathophysiology and clinical sequalae involved in neuroinflammation and neurodegenerative diseases.

Methods

We searched PubMed database for relevant publications on curcumin and its uses in treating neurological diseases. We also reviewed relevant clinical trials which appeared on searching PubMed database using 'Curcumin and clinical trials'.

Results

This review details the pleiotropic immunomodulatory functions and neuroprotective properties of curcumin, its derivatives and formulations in various preclinical and clinical investigations. The effects of curcumin on neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), brain tumors, epilepsy, Huntington's disorder (HD), ischemia, Parkinson's disease (PD), multiple sclerosis (MS), and traumatic brain injury (TBI) with a major focus on associated signalling pathways have been thoroughly discussed.

Conclusion

This review demonstrates curcumin can suppress spinal neuroinflammation by modulating diverse astroglia mediated cascades, ensuring the treatment of neurological disorders.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN AND METHODS

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

RESULTS

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

CONCLUSION

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

Hypoglycemic medicines in the treatment of Alzheimer's disease: Pathophysiological links between AD and glucose metabolism

Alzheimer's Disease (AD) is a global chronic disease in adults with beta-amyloid (Aβ) deposits and hyperphosphorylated tau protein as the pathologic characteristics. Although the exact etiology of AD is still not fully elucidated, aberrant metabolism including insulin signaling and mitochondria dysfunction plays an important role in the development of AD. Binding to insulin receptor substrates, insulin can transport through the blood-brain barrier (BBB), thus mediating insulin signaling pathways to regulate physiological functions. Impaired insulin signaling pathways, including PI3K/Akt/GSK3β and MAPK pathways, could cause damage to the brain in the pathogenesis of AD. Mitochondrial dysfunction and overexpression of TXNIP could also be causative links between AD and DM. Some antidiabetic medicines may have benefits in the treatment of AD. Metformin can be beneficial for cognition improvement in AD patients, although results from clinical trials were inconsistent. Exendin-4 may affect AD in animal models but there is a lack of clinical trials. Liraglutide and dulaglutide could also benefit AD patients in adequate clinical studies but not semaglutide. Dipeptidyl peptidase IV inhibitors (DPP4is) such as saxagliptin, vildagliptin, linagliptin, and sitagliptin could boost cognitive function in animal models. And SGLT2 inhibitors such as empagliflozin and dapagliflozin were also considerably protective against new-onset dementia in T2DM patients. Insulin therapy is a promising therapy but some studies indicated that it may increase the risk of AD. Herbal medicines are helpful for cognitive function and neuroprotection in the brain. For example, polyphenols, alkaloids, glycosides, and flavonoids have protective benefits in cognition function and glucose metabolism. Focusing on glucose metabolism, we summarized the pharmacological mechanism of hypoglycemic drugs and herbal medicines. New treatment approaches including antidiabetic synthesized drugs and herbal medicines would be provided to patients with AD. More clinical trials are needed to produce definite evidence for the effectiveness of hypoglycemic medications.

Effects of curcumin, a bioactive component of turmeric, on type 2 diabetes mellitus and its complications: an updated review

Type 2 diabetes mellitus (T2DM) is a substantial issue in public health. Recently, there has been considerable interest in the effectiveness of using herbal supplements for T2DM. Among the herbal supplements, turmeric (Curcuma longa L.) has been attracting an avalanche of attention owing to its main component, curcumin. This review examines the physiological activities and mechanisms of action of curcumin associated with T2DM and its complications. The literature indicates that pro-inflammatory cytokines along with oxidative stress play a very important role in diabetes pathogenesis. Since inflammation is a main cause of disruption of the β cell structure, the anti-diabetic characteristic of curcumin is mainly attributed to its anti-inflammatory as well as anti-oxidant activities. In addition to these activities, curcumin has been developed as a promising prevention/treatment choice for diabetes complications by modulating various critical signal steps owing to the anti-hyperglycemic and anti-hyperlipidemic activities of curcumin. Studies on diabetic humans and animals have revealed that curcumin may have positive effects on oxidative stress and inflammation and may reduce fasting blood glucose levels, increase insulin sensitivity/secretion and regulate the lipid profile. Thus, it may prevent and treat diabetes by affecting various molecular targets.

Palliative effect of Moringa olifera-mediated zinc oxide nanoparticles against acrylamide-induced neurotoxicity in rats

Repeated acrylamide (ACR) exposure in experimental animals and humans causes variable degrees of neuronal damage. Because of its unique features, several green synthesized nanomaterials are explored for neuromodulatory activity. Hence, this study investigated the effect of green synthesized zinc oxide nanoparticles using Moriga olifera leaves extract (MO-ZnONP) against acrylamide (ACR)-induced neurobehavioral and neurotoxic impacts in rat. Forty male Sprague Dawley rats were distributed into four groups orally given distilled water, MO-ZnONP (10 mg/kg b.wt), ACR (20 mg/kg b.wt), or MO-ZnONP + ACR for 60 days. Gait quality and muscular, motor, and sensory function were assessed. Acetylcholinesterase (AChE), dopamine, catalase, malondialdehyde (MDA), and Zn brain contents were determined. Brain histopathology and immunohistochemical localization of the amyloid-β protein and abnormal Tau were performed. The results revealed that MO-ZnONP significantly reduced ACR-induced sensory dysfunctions, hind limb abnormality, and motor deficits. Additionally, the ACR-induced increase in dopamine and AChE were significantly supressed by MO-ZnONP. Besides, MO-ZnONP significantly restored catalase and Zn content but reduced increased MDA brain content resulting from ACR. Furthermore, the ACR-induced neurodegenerative changes and increased amyloid-β and phosphorylated Tau immunoexpression was significantly abolished by MO-ZnONP. Conclusively, MO-ZnONP could be used as a biologically effective compound for mitigating ACR's neurotoxic and neurobehavioral effects.

Nutritional intervention for diabetes mellitus with Alzheimer's disease

The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.

Palm Oil Derived Tocotrienol-Rich Fraction Attenuates Vascular Dementia in Type 2 Diabetic Rats

Vascular dementia (VaD) is a serious global health issue and type 2 diabetes mellitus (T2DM) patients are at higher risk. Palm oil tocotrienol-rich fraction (TRF) exhibits neuroprotective properties; however, its effect on VaD is not reported. Hence, we evaluated TRF effectiveness in T2DM-induced VaD rats. Rats were given a single dose of streptozotocin (STZ) and nicotinamide (NA) to develop T2DM. Seven days later, diabetic rats were given TRF doses of 30, 60, and 120 mg/kg orally for 21 days. The Morris water maze (MWM) test was performed for memory assessment. Biochemical parameters such as blood glucose, plasma homocysteine (HCY) level, acetylcholinesterase (AChE) activity, reduced glutathione (GSH), superoxide dismutase (SOD) level, and histopathological changes in brain hippocampus and immunohistochemistry for platelet-derived growth factor-C (PDGF-C) expression were evaluated. VaD rats had significantly reduced memory, higher plasma HCY, increased AChE activity, and decreased GSH and SOD levels. However, treatment with TRF significantly attenuated the biochemical parameters and prevented memory loss. Moreover, histopathological changes were attenuated and there was increased PDGF-C expression in the hippocampus of VaD rats treated with TRF, indicating neuroprotective action. In conclusion, this research paves the way for future studies and benefits in understanding the potential effects of TRF in VaD rats.

Curcumin-loaded hydroxypropyl-β-cyclodextrin inclusion complex with enhanced dissolution and oral bioavailability for epilepsy treatment

Curcumin, the main bioactive component of turmeric, has a wild range of beneficial effects on central nervous diseases, including anti-Alzheimer's disease, antioxidant stress, and anti-inflammation. Currently, it has been demonstrated the anti-epileptic potential. However, curcumin has poor water solubility, high sensitivity to light and heat, and low absorption, which results in low bioavailability and greatly limits the clinical application of curcumin, as well as the elusive effects in anti-epileptic treatment.This study aimed to develop a curcumin hydroxypropyl-β-cyclodextrin inclusion complex (CUR-HP-β-CD) to improve its bioavailability and facilitate its potential development as an anti-epileptic drug. The CUR-HP-β-CD was generated by the solvent evaporation method, which has efficient entrapment, high solubility, and facilitated bioavailability and brain distribution.The solubility of the CUR-HP-β-CD was 63.5, 60.1, and 52.9 times that of the unformulated curcumin in H₂O, HCl (pH 1.2), and PBS (pH 6.8), respectively. The bioavailability of CUR-HP-β-CD is improved 2.8 times and 38.7 folds higher brain concentrations. Moreover, the therapeutic anti-epileptic effects of CUR-HP-β-CD were much more effective in pentylenetetrazol (PTZ)-induced zebrafish and mouse models.This study showed a simple and reproducible strategy to effectively improve the bioavailability and therapeutic effects of curcumin, which could be potentially used in epilepsy treatment.