Therapeutic potential of thymoquinone and its nanoformulations in neuropsychological disorders: a comprehensive review on molecular mechanisms in preclinical studies

Thymoquinone (THQ) and its nanoformulation (NFs) have emerged as promising candidates for the treatment of neurological diseases due to their diverse pharmacological properties, which include anti-inflammatory, antioxidant, and neuroprotective effects. In this study, we conducted an extensive search across reputable scientific websites such as PubMed, ScienceDirect, Scopus, and Google Scholar to gather relevant information. The antioxidant and anti-inflammatory properties of THQ have been observed to enhance the survival of neurons in affected areas of the brain, leading to significant improvements in behavioral and motor dysfunctions. Moreover, THQ and its NFs have demonstrated the capacity to restore antioxidant enzymes and mitigate oxidative stress. The primary mechanism underlying THQ's antioxidant effects involves the regulation of the Nrf2/HO-1 signaling pathway. Furthermore, THQ has been found to modulate key components of inflammatory signaling pathways, including toll-like receptors (TLRs), nuclear factor-κB (NF-κB), interleukin 6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα), thereby exerting anti-inflammatory effects. This comprehensive review explores the various beneficial effects of THQ and its NFs on neurological disorders and provides insights into the underlying mechanisms involved.

Prunetin in a GPR30-dependent manner mitigates renal ischemia/reperfusion injury in rats via interrupting indoxyl sulfate/TLR4/TRIF, RIPK1/RIPK3/MLKL, and RIPK3/PGAM5/DRP-1 crosstalk

The potential health benefits of phytochemicals in preventing and treating diseases have gained increasing attention. Here, we proved that the methylated isoflavone prunetin possesses a reno-therapeutic effect against renal ischemia/reperfusion (I/R) insult by activating G protein-coupled receptor 30 (GPR30). After choosing the therapeutic dose of prunetin against renal I/R injury in the pilot study, male Sprague Dawley rats were allocated into 5 groups; viz., sham-operated (SO), SO injected with 1 mg/kg prunetin intraperitoneally for three successive days, untreated I/R, I/R treated with prunetin, and I/R treated with G-15, the selective GPR30 blocker, followed by prunetin. Treatment with prunetin reversed the I/R renal injury effect and majorly restored normal renal function and architecture. Mechanistically, prunetin restored the I/R-induced depletion of renal GPR30, an impact that was canceled by the pre-administration of G-15. Additionally, post-administration of prunetin normalized the boosted inflammatory markers indoxyl sulfate, TLR4, and TRIF and abrogated renal cell demise by suppressing necroptotic signaling, verified by the inactivation of p-RIPK1, p-RIPK3, and p-MLKL while normalizing the inhibited caspase-8. Besides, prunetin reversed the I/R-mediated mitochondrial fission by inhibiting the protein expression of PGMA5 and p-DRP-1. All these favorable impacts of prunetin were nullified by G-15. To sum up, prunetin exhibited a significant reno-therapeutic effect evidenced by the enhancement of renal morphology and function, the suppression of the inflammatory cascade indoxyl sulfate/TLR4/TRIF, which turns off the activated/phosphorylated necroptotic trajectory RIPK1/RIPK3/MLKL, while enhancing caspase-8. Additionally, prunetin opposed the mitochondrial fission pathway RIPK3/PGMA5/DRP-1, effects that are mediated via the activation of GPR30.

The Potential Neuroprotective Effect of Thymoquinone on Scopolamine-Induced In Vivo Alzheimer's Disease-like Condition: Mechanistic Insights

BACKGROUND

Alzheimer's disease (AD) is a common neurodegenerative disorder without effective treatment. Thymoquinone (TQ) has demonstrated potential in exhibiting anti-inflammatory, anti-cancer, and antioxidant characteristics. Despite TQ's neuroprotection effect, there is a scarcity of information regarding its application in AD research, and its molecular trajectories remain ambiguous. Thus, the objective of the current investigation was to examine the potential beneficial effects and underlying mechanisms of TQ in scopolamine (SCOP)-induced neuronal injury to mimic AD in vivo model.

METHODS

Thirty mice were divided into normal, SCOP, and TQ groups. The Y-maze and pole climbing tests were performed to measure memory and motor performance. Afterwards, histopathological and immunohistochemical examinations were carried out. Furthermore, peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling pathway-related proteins and genes were detected with an emphasis on the role of miR-9.

RESULTS

TQ has the potential to ameliorate cognitive deficits observed in SCOP-induced AD-like model, as evidenced by the improvement in behavioral outcomes, histopathological changes, modulation of the expression pattern of PPAR-γ downstream targets with a significant decrease in the deposition of amyloid beta (Aβ).

CONCLUSIONS

TQ provided meaningful multilevel neuroprotection through its anti-inflammatory and its PPAR-γ agonist activity. Consequently, TQ may possess a potential beneficial role against AD development.

How to Naturally Support the Immune System in Inflammation-Essential Oils as Immune Boosters

Efficient functionality of the immune system is needed to fight against the development of infectious diseases, including, among others, serious recurrent chronic infections. Research has shown that many modern common diseases, such as inflammatory bowel diseases and cardiovascular diseases, e.g., thromboembolism, cancer, obesity, or depression, are connected with inflammatory processes. Therefore, new, good stimulators of the immune system's response are sought. They include synthetic compounds as well as biological preparations such as lipopolysaccharides, enzymes, bacterial metabolites, and secondary metabolites of plants, demonstrating a multidirectional effect. Essential oils are characterized by many invaluable activities, including antimicrobial, antioxidant, anti-inflammatory, and immunostimulating. Essential oils may stimulate the immune system via the utilization of their constituents, such as antibodies, cytokines, and dendritic cells. Some essential oils may stimulate the proliferation of immune-competent cells, including polymorphonuclear leukocytes, macrophages, dendritic cells, natural killer cells, and B and T lymphocytes. This review is focused on the ability of essential oils to affect the immune system. It is also possible that essential oil components positively interact with recommended anti-inflammatory and antimicrobial drugs. Thus, there is a need to explore possible synergies between essential oils and their active ingredients for medical use.

Effects of thymoquinone and memantine alone and in combination on memory and hippocampal morphology in rats with streptozotocin-induced Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disease. Thymoquinone (TQ) has broad biological functions, including antiinflammatory, antioxidant, neuroprotective properties. Memantine (MEM) is indicated for the symptomatic treatment of moderate to severe AD. We aimed to evaluate the effect of TQ alone or in combination with MEM on memory and hippocampal morphology in an STZ-induced rat AD model.

METHODS

Thirty male rats were included in this study. The AD model was created by giving ICV STZ. The rats were divided into 5 groups (n = 6 each). Group 1 (control group): The rats received only ICV-STZ 3 mg/kg for 2 weeks. Group 2 (sham group): In addition to ICV STZ, 9% NaCl, 1 mL/day i.p. for 2 weeks of injection, was applied. Group 3 (TQ group): In addition to ICV STZ, rats received TQ 10 mg/kg i.p. for 2 weeks. Group 4 (MEM group): In addition to ICV STZ, rats were given MEM at a dose of 5 mg/kg for two weeks. Group 5 (TQ+MEM group): In addition to ICV STZ, this group was given TQ (10 mg/kg/day, i.p.) and MEM (5 mg/kg/day, i.p.) for 2 weeks. On the 15th day, passive avoidance learning (PAL) was applied to all groups. Then, rats were sacrificed, neurons in the hippocampal CA1, CA2, CA3 regions were evaluated.

RESULTS

Groups 3, 4, 5 had longer latency periods than groups 1 and 2. The neuron density in the CA1, CA2, CA3 regions had decreased in groups 1 and 2 compared to groups 3, 4, 5. There were significantly more neurons in groups 3, 4, 5 than in groups 1 and 2.

DISCUSSION

We found that TQ alone and in combination with MEM showed ameliorative effects on memory and hippocampal morphology. TQ may offer a promising treatment strategy for AD.

Nanomedicine in the Management of Alzheimer's Disease: State-of-the-Art

Alzheimer's disease (AD) is a deadly, progressive, and irreversible brain condition that impairs cognitive abilities. Globally, it affects 32.6 million individuals, and if no viable therapies are available by 2050, that figure might rise to 139 million. The current course of treatment enhances cognitive abilities and temporarily relieves symptoms, but it does not halt or slow the disease's development. Additionally, treatments are primarily offered in conventional oral dosage forms, and conventional oral treatments lack brain specialization and cause adverse effects, resulting in poor patient compliance. A potential nanotechnology-based strategy can improve the bioavailability and specificity of the drug targeting in the brain. Furthermore, this review extensively summarizes the applications of nanomedicines for the effective delivery of drugs used in the management of AD. In addition, the clinical progress of nanomedicines in AD is also discussed, and the challenges facing the clinical development of nanomedicines are addressed in this article.

Nigella sativa and its nano-mediated approach toward management of neurodegenerative disorders: A review

Nigella sativa L., also known as black seed or black cumin, is a plant that has been used for centuries. In the past, this flowering plant was used as a food preservative and medicinal herb. A vital component of Nigella sativa, thymoquinone (TQ), plays a significant therapeutic role in the management of most diseases, including cancer, diabetes mellitus, hypertension, inflammation, gastrointestinal disorders, and neurodegenerative disorders. Neurodegenerative disorders are primarily caused by neurotransmitter hypoactivity, particularly insufficient serotonin activity. It has been discovered that many medicinal herbs and their active compounds have therapeutic value. Black cumin seeds have been used to heal ailments and its history traces back to ancient times such as ancient Babylonia. They can be used applied to alleviate edema, hair loss, and bruising, and consumd to treat stomach issues. It is one of the most feasible and effective medicinal plants. The use of nanoformulations based on Nigella sativa and TQ to treat neurodegenerative diseases (NDs) has yielded promising outcomes. Customized administration of nanoparticle (NP) systems and nanomedicine are two of the many options for drug delivery to the central nervous system (CNS) that are attracting increasing interest. Delivering a therapeutic and diagnostic substance to a particular location is the core target of NPs. Because of their distinct cell uptake and trafficking mechanisms, NPs can reduce the amount that accumulates in undesirable organs. The focus of the current review is on recent studies on the various neuroprotective properties of Nigella sativa as well as nanoformulations for NDs and the brain's uptake of NPs. The review summarizes the In vivo, In vitro, and In silico studies on the protective effects of black cumin against neurodegenerative disorders.

Anti-Neuroinflammatory Potential of Natural Products in the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is an age-related chronic progressive neurodegenerative disease, which is the main cause of dementia in the elderly. Much evidence shows that the onset and late symptoms of AD are caused by multiple factors. Among them, aging is the main factor in the pathogenesis of AD, and the most important risk factor for AD is neuroinflammation. So far, there is no cure for AD, but the relationship between neuroinflammation and AD may provide a new strategy for the treatment of AD. We herein discussed the main etiology hypothesis of AD and the role of neuroinflammation in AD, as well as anti-inflammatory natural products with the potential to prevent and alleviate AD symptoms, including alkaloids, steroids, terpenoids, flavonoids and polyphenols, which are available with great potential for the development of anti-AD drugs.

The application of nanotechnology in treatment of Alzheimer's disease

The buildup of beta-amyloid plaques in the brain results in Alzheimer's disease (AD), a neurodegenerative condition. A permanent treatment for AD is not yet available. Only a slowing down of its advancement is possible with the current pharmaceutical options. Nevertheless, nanotechnology has proven to be advantageous in medical applications. It has a lot of potential for AD therapy, particularly in diagnosing the condition and providing an alternative course of treatment. In this review, we outline the developments and benefits of nanomedicines in treating AD. Prospective nanomedicines for diagnosing and surveillance therapeutic interventions for AD and other diseases of the central nervous system (CNS) may be clinically accessible, persuading the development of investigation in this field.

The Effect of Thymoquinone on Oxidative Stress Parameters and Apolipoprotein E in Alzheimer Model in Rats

INTRODUCTION

In this study, it was aimed to investigate the effect of thymoquinone (TQ) on oxidative stress and apolipoprotein E (ApoE) in an experimental Alzheimer's model created with AlCl3 and D-galactose in rats.

METHODS

Thirty-six Wistar Albino male rats saline group (Group 1), aluminum chloride (AlCl3) + D-galactose (D-Gal) group (Group 2), AlCl3 + D-Gal + TQ group (Group 3) were divided into 3 groups. The study was completed with 33 rats. Group 1 was given saline intraperitoneally (i.p) for 28 days. 2nd group; D-Gal at a dose of 60 mg/kg/day and AlCl3 at a dose of 40 mg/kg/day were given i.p. daily for 28 days. 3rd group; D-Gal at a dose of 60 mg/kg/day and AlCl3 at a dose of 40 mg/kg/day were given i.p. daily for 28 days. Group 3 rats were given 20 mg/kg/day TQ in corn oil by gavage for 14 days. Malonyl dialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (TAS), total oxidant capacity (TOS), glutathione peroxidase (GsH-Px), and ApoE levels were determined in the blood and brain tissues of rats in all three groups. One-way ANOVA test was used in the statistical analysis of the data.

RESULTS

Means of TAS, TOS, GSH-Px, SOD, MDA, and ApoE in blood and brain tissue of all three groups (excluding ApoE in brain tissue) were different from each other and this difference was statistically significant (p < 0.05).

CONCLUSION

In this study, TQ, it was determined that all oxidative stress parameters examined had positively affected and decreased blood tissue ApoE levels. TQ can be used as an antioxidant and curative in Alzheimer's disease.

From kitchen to clinic: Pharmacotherapeutic potential of common spices in Indian cooking in age-related neurological disorders

Aging is described as an advanced time-related collection of changes that may negatively affect with the risk of several diseases or death. Aging is a main factor of several age-related neurological disorders, including neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, and dementia), stroke, neuroinflammation, neurotoxicity, brain tumors, oxidative stress, and reactive oxygen species (ROS). Currently available medications for age-related neurological disorders may lead to several side effects, such as headache, diarrhea, nausea, gastrointestinal (GI) diseases, dyskinesia, and hallucinosis. These days, studies on plant efficacy in traditional medicine are being conducted because herbal medicine is affordable, safe, and culturally acceptable and easily accessible. The Indian traditional medicine system called Ayurveda uses several herbs and medicinal plants to treat various disorders including neurological disorders. This review aims to summarize the data on the neuroprotective potential of the following common Indian spices widely used in Ayurveda: cumin (Cuminum cyminum (L.), Apiaceae), black cumin (Nigella sativa (L.), Ranunculaceae), black pepper (Piper nigrum (L.), Piperaceae), curry leaf tree (Murraya koenigii (L.), Spreng Rutaceae), fenugreek (Trigonella foenum-graecum (L.), Fabaceae), fennel (Foeniculum vulgare Mill, Apiaceae), cardamom (Elettaria cardamomum (L.) Maton, Zingiberaceae), cloves (Syzygium aromaticum (L.) Merr. & L.M.Perry, Myrtaceae), and coriander (Coriandrum sativum (L.), Apiaceae) in age-related neurological disorders.

Quercetin Nanoemulsion Ameliorates Neuronal Dysfunction in Experimental Alzheimer's Disease Model

Aluminum is the most abundant metal that can get admission to the human through several means that include our food, drinking water, cans, drugs, and deodorants, causing neurodegenerative diseases such as Alzheimer's disease (AD). The present study aims to evaluate the role of quercetin nanoemulsion (QCNE) in attenuating neuronal dysfunction in aluminum chloride (AlCl3)-induced experimental AD. All animals were classified into six groups including negative control group (I): received a vehicle; QC group: received intraperitoneal (IP) injection of QC; Alzheimer's group: received AlCl3 orally; treated group (I): received AlCl3 orally and IP injection of QC; treated group (II): received AlCl3 orally and QC orally; and treated group (III): received AlCl3 orally and IP injection of QCNE. At the end of the experimental period (30 days), the brain was used to study biochemical parameters (measurement of neurotransmitters (serotonin, dopamine, and norepinephrine), oxidant/antioxidant parameters (reduced glutathione, malondialdehyde, superoxide dismutase, and advanced oxidation protein product), and inflammatory markers (adiponectin, interleukin 1β, and plasma tumor necrosis factor-alpha)), while another part was for brain immune-histochemical analysis (study cyclooxygenases (COX-1 and COX-2)). Results showed that the mean value of oxidative stress markers was significantly increased in the AD group as well as the inflammatory biomarkers and all the study neurotransmitters, whereas these parameters were attenuated in treated groups, especially those that received QCNE. The immunohistochemistry findings confirm our results. Both approaches (QC and QCNE) succeeded in retracting the negative impact of AlCl3. Meanwhile, the effect of QCNE is more potent in mitigating the impact mediated by AlCl3 in treated animals. In conclusion, the treatment mainly by QCNE has huge potential in protecting against AlCl3-induced neuronal dysfunction, as shown in our results by the elevation of brain antioxidant/anti-inflammatory activities and neurotransmitter levels as well as mending of the histopathological changes in animal models.

The Role of Thymoquinone in Inflammatory Response in Chronic Diseases

Anti-inflammatory therapies have been shown to be effective in the prevention of various cardiovascular diseases, tumors, and cancer complications. Thymoquinone (TQ), the main active constituent of Nigella sativa, has shown promising therapeutic properties in many in vivo and in vitro models. However, TQ has poor bioavailability and is hydrophobic, prohibiting clinical trials with TQ alone. Studies have explored the combination of TQ with biological nanomaterials to improve its bioavailability. The TQ nanoparticle formulation shows better bioavailability than free TQ, and these formulations are ready for clinical trials to determine their potential as therapeutic agents. In this paper, we review current knowledge about the interaction between TQ and the inflammatory response and summarize the research prospects in Korea and abroad. We discuss the different biological activities of TQ and various combination therapies of TQ and nanomaterials in clinical trials.

Nanomedicines in the Management of Alzheimer’s Disease: Current View and Future Prospects

Alzheimer’s disease (AD) is a kind of dementia that creates serious challenges for sufferers’ memory, thinking, and behavior. It commonly targeting the aging population and decay the brain cells, despite attempts have been performed to enhance AD diagnostic and therapeutic techniques. Hence, AD remains incurable owing to its complex and multifactorial consequences and still there is lack of appropriate diagnostics/therapeutics option for this severe brain disorder. Therefore, nanotechnology is currently bringing new tools and insights to improve the previous knowledge of AD and ultimately may provide a novel treatment option and a ray of hope to AD patients. Here in this review, we highlighted the nanotechnologies-based findings for AD, in both diagnostic and therapeutic aspects and explained how advances in the field of nanotechnology/nanomedicine could enhance patient prognosis and quality of life. It is highly expected these emerging technologies could bring a research-based revolution in the field of neurodegenerative disorders and may assist their clinical experiments and develop an efficacious drug for AD also. The main aim of review is to showcase readers the recent advances in nanotechnology-based approaches for treatment and diagnosing of AD.

Demystifying phytoconstituent-derived nanomedicines in their immunoregulatory and therapeutic roles in inflammatory diseases

In the past decades, phytoconstituents have appeared as critical mediators for immune regulations among various diseases, both in eukaryotes and prokaryotes. These bioactive molecules, showing a broad range of biological functions, would hold tremendous promise for developing new therapeutics. The discovery of phytoconstituents' capability of functionally regulating immune cells and associating cytokines, suppressing systemic inflammation, and remodeling immunity have rapidly promoted the idea of their employment as anti-inflammatory agents. In this review, we discuss various roles of phyto-derived medicines in the field of inflammatory diseases, including chronic inflammation, autoimmune diseases, and acute inflammatory disease such as COVID-19. Nevertheless, traditional phyto-derived medicines often concurred with their clinical administration limitations, such as their lack of cell specificity, inefficient cytoplasmic delivery, and rapid clearance by the immune system. As alternatives, phyto-derived nano-approaches may provide significant benefits. Both unmodified and engineered nanocarriers present the potential to serve as phytoconstituent delivery systems to improve therapeutic physio-chemical properties and pharmacokinetic profiles. Thus, the development of phytoconstituents' nano-delivery designs, their new and perspective approaches for therapeutical applications are elaborated herein.

Molecular Signaling Pathway Targeted Therapeutic Potential of Thymoquinone in Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disease with rapid progression. Black cumin (Nigella sativa) is a nutraceutical that has been investigated as a prophylactic and therapeutic agent for this disease due to its ability to prevent or retard the progression of neurodegeneration. Thymoquinone (TQ) is the main bioactive compound isolated from the seeds of black cumin. Several reports have shown that it has promising potential in the prevention and treatment of AD due to its significant antioxidative, anti-inflammatory, and antiapoptotic properties along with several other mechanisms that target the altered signaling pathways due to the disease pathogenesis. In addition, it shows anticholinesterase activity and prevents α-synuclein induced synaptic damage. The aim of this review is to summarize the potential aspects and mechanisms by which TQ imparts its action in AD.

Celastrol and thymoquinone alleviate aluminum chloride-induced neurotoxicity: Behavioral psychomotor performance, neurotransmitter level, oxidative-inflammatory markers, and BDNF expression in rat brain

Exposure to aluminum chloride (AlCl₃) induces progressive multiregional neurodegeneration in animal models by promoting oxidative stress and neuroinflammation. The current study was designed to assess the potential efficacy of the natural antioxidants celastrol and thymoquinone (TQ) for alleviating AlCl₃-induced psychomotor abnormalities and oxidative-inflammatory burden in male albino rats. Four treatment groups were compared: (i) a vehicle control group, (ii) a AlCL₃ group receiving daily intraperitoneal (i.p.) injection of AlCl₃ (10 mg/kg) for 6 weeks, (iii) a AlCl₃ plus TQ (10 mg/kg, i.p.) cotreatment group, and (iv) a AlCl₃ plus celastrol (1 mg/kg, i.p.) cotreatment group. Open-field, rotarod, and forced swimming tests were conducted to assess locomotor activity, motor coordination, anxiety-like behavior, and depressive-like behavior. Acetylcholine (ACh), dopamine, and serotonin levels were measured in brain homogenates. Malondialdehyde (MDA), total antioxidant capacity (TAC), and catalase activity were measured as oxidative stress markers, while tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) expression levels were measured as inflammatory markers. Brain derived neurotrophic factor (BDNF) mRNA was measured as an index for the endogenous neuroprotective response. Daily AlCl₃ injection reduced free ambulation, impaired motor coordination, promoted anxiety- and depression-like behaviors, reduced whole-brain ACh, dopamine, and serotonin concentrations, increased MDA accumulation, reduced TAC, elevated TNF-α and IL-6, and suppressed BDNF mRNA expression. All of these effects were significantly reversed by TQ or celastrol cotreatment. Thus, TQ and celastrol may be promising treatments for AlCl₃-induced neurotoxicity as well as neurodegenerative diseases involving oxidative stress and neuroinflammation.

Investigating binding mechanism of thymoquinone to human transferrin, targeting Alzheimer's disease therapy

Iron deposition in the central nervous system (CNS) is one of the causes of neurodegenerative diseases. Human transferrin (hTf) acts as an iron carrier present in the blood plasma, preventing it from contributing to redox reactions. Plant compounds and their derivatives are frequently being used in preventing or delaying Alzheimer's disease (AD). Thymoquinone (TQ), a natural product has gained popularity because of its broad therapeutic applications. TQ is one of the significant phytoconstituent of Nigella sativa. The binding of TQ to hTf was determined by spectroscopic methods and isothermal titration calorimetry. We have observed that TQ strongly binds to hTf with a binding constant (K) of 0.22 × 10⁶ M^-1 and forming a stable complex. In addition, isothermal titration calorimetry revealed the spontaneous binding of TQ with hTf. Molecular docking analysis showed key residues of the hTf that were involved in the binding to TQ. We further performed a 250 ns molecular dynamics simulation which deciphered the dynamics and stability of the hTf-TQ complex. Structure analysis suggested that the binding of TQ doesn't cause any significant alterations in the hTf structure during the course of simulation and a stable complex is formed. Altogether, we have elucidated the mechanism of binding of TQ with hTf, which can be further implicated in the development of a novel strategy for AD therapy.

An Overview of the Neuropharmacological Potential of Thymoquinone and its Targeted Delivery Prospects for CNS Disorder

At present, people and patients worldwide are relying on the medicinal plant as a therapeutic agent over pharmaceuticals because the medicinal plant is considered safer, especially for chronic disorders. Several medicinal plants and their components are being researched and explored for their possible therapeutic contribution to CNS disorders. Thymoquinone (TQ) is one such molecule. Thymoquinone, one of the constituents of Plant Nigella Sativa, is effective against several neurodegenerative diseases like; Alzheimer's, Depression, Encephalomyelitis, Epilepsy, Ischemia, Parkinson's, and Traumatic. This review article presents the neuropharmacological potential of TQ's, their challenges, and delivery prospects, explicitly focusing on neurological disorders along with their chemistry, pharmacokinetics, and toxicity. Since TQ has some pharmacokinetic challenges, scientists have focused on novel formulations and delivery systems to enhance bioavailability and ultimately increase its therapeutic value. In the present work, the role of nanotechnology in neurodegenerative disease and how it improves bioavailability and delivery of a drug to the site of action has been discussed. There are a few limitations for developing novel drug formulation, including solubility, pH, and compatibility of nanomaterials. Since here we are targeting CNS disorders, the blood-brain barrier (BBB) becomes an additional challenge Hence, the review summarized the novel aspects of delivery and biocompatible nanoparticles-based approaches for targeted drug delivery into CNS, enhancing TQ bioavailability and its neurotherapeutic effects.

Thymoquinone-Mediated Modulation of Toll-like Receptors and Pluripotency Factors in Gingival Mesenchymal Stem/Progenitor Cells

Thymoquinone (TQ), the key active component of Nigella sativa (NS), demonstrates very promising biomedical anti-inflammatory, antioxidant, antimicrobial and anticancer properties. Several investigations have inspected the modulative activities of TQ on different stem/progenitor cell types, but its possible role in the regulation of gingival mesenchymal stem/progenitor cells (G-MSCs) has not yet been characterized. For the first time, this study investigates the effects of TQ on G-MSCs’ stemness and Toll-like receptor expression profiles. G-MSCs (n = 5) were isolated, sorted via anti-STRO-1 antibodies and then disseminated on cell culture dishes to create colony-forming units (CFUs), and their stem/progenitor cell attributes were characterized. TQ stimulation of the G-MSCs was performed, followed by an examination of the expression of pluripotency-related factors using RT-PCR and the expression profiles of TLRs 1−10 using flowcytometry, and they were compared to a non-stimulated control group. The G-MSCs presented all the predefined stem/progenitor cells’ features. The TQ-activated G-MSCs displayed significantly higher expressions of TLR3 and NANOG with a significantly reduced expression of TLR1 (p < 0.05, Wilcoxon signed-rank test). TQ-mediated stimulation preserves G-MSCs’ pluripotency and facilitates a cellular shift into an immunocompetent-differentiating phenotype through increased TLR3 expression. This characteristic modulation might impact the potential therapeutic applications of G-MSCs.

Thymoquinone Improved Nonylphenol-Induced Memory Deficit and Neurotoxicity Through Its Antioxidant and Neuroprotective Effects

Nonylphenol (NP), a well-known endocrine-disrupter chemical, has several harmful effects on the central nervous system including neuroendocrine disruption, cognitive impairment, and neurotoxicity. Thymoquinone (TQ) is a main bioactive compound in the black seeds of Nigella sativa that has antioxidant, anti-inflammatory, and neuroprotective properties. Here, we investigated the neuroprotective effect of TQ against NP-induced memory deficit and neurotoxicity in rats. To induce memory impairment, NP (25 mg/kg) was used as gavage in male Wistar rats for 21 days. TQ (2.5, 5, and 10 mg/kg) was intraperitoneally administered in NP-treated animals. The morris water maze test was performed to assess spatial learning and memory. The hippocampal tissues were isolated from the brain for histopathological evaluation. Biochemical, molecular, and cellular tests were performed to quantify oxidant (malondialdehyde; MDA)/antioxidant (superoxide dismutase (SOD), total antioxidant capacity (TAC), and reduced glutathione (GSH) parameters) as well as markers for astrocytic activation (glial fibrillary acidic protein; GFAP) and neuronal death (alpha-synuclein; α-syn). Results showed TQ (5 mg/kg) significantly improved NP-induced memory impairment. Histological data revealed a significant increase in the number of necrotic cells in hippocampus, and TQ treatment markedly decreased this effect. The GSH and TAC levels were significantly increased in TQ-treated groups compared to NP group. The molecular analysis indicated that NP increased GFAP and decreased α-syn expression and TQ treatment did the reverse. In vitro study in astrocytes isolated from mice brain showed that TQ significantly increased cell viability in NP-induced cytotoxicity. This study strongly indicates that TQ has neuroprotective effects on NP-induced neurotoxicity through reducing oxidative damages and neuroinflammation. This study investigates the behavioral neurotoxicity induced by Nonylphenol (NP) and the protective effects of Thymoquinone (TQ) as a potent antioxidant compound using molecular, cell culture, histopathological and biochemical techniques.

Thymoquinone: Review of Its Potential in the Treatment of Neurological Diseases

Thymoquinone (TQ) possesses anticonvulsant, antianxiety, antidepressant, and antipsychotic properties. It could be utilized to treat drug misuse or dependence, and those with memory and cognitive impairment. TQ protects brain cells from oxidative stress, which is especially pronounced in memory-related regions. TQ exhibits antineurotoxin characteristics, implying its role in preventing neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease. TQ’s antioxidant and anti-inflammatory properties protect brain cells from damage and inflammation. Glutamate can trigger cell death by causing mitochondrial malfunction and the formation of reactive oxygen species (ROS). Reduction in ROS production can explain TQ effects in neuroinflammation. TQ can help prevent glutamate-induced apoptosis by suppressing mitochondrial malfunction. Several studies have demonstrated TQ’s role in inhibiting Toll-like receptors (TLRs) and some inflammatory mediators, leading to reduced inflammation and neurotoxicity. Several studies did not show any signs of dopaminergic neuron loss after TQ treatment in various animals. TQ has been shown in clinical studies to block acetylcholinesterase (AChE) activity, which increases acetylcholine (ACh). As a result, fresh memories are programmed to preserve the effects. Treatment with TQ has been linked to better outcomes and decreased side effects than other drugs.

Thymoquinone in Ocular Neurodegeneration: Modulation of Pathological Mechanisms via Multiple Pathways

Thymoquinone is a naturally occurring compound and is the major component of Nigella sativa, also known as black seed or black cumin. For centuries thymoquinone has been used especially in the Middle East traditionally to treat wounds, asthma, allergies, fever, headache, cough, hypertension, and diabetes. Studies have suggested beneficial effects of thymoquinone to be attributed to its antioxidant, antibacterial, anti-oxidative stress, anti-inflammatory, and neuroprotective properties. Recently, there has been a surge of interest in thymoquinone as a treatment for neurodegeneration in the brain, such as that seen in Alzheimer’s (AD) and Parkinson’s diseases (PD). In vitro and in vivo studies on animal models of AD and PD suggest the main neuroprotective mechanisms are based on the anti-inflammatory and anti-oxidative properties of thymoquinone. Neurodegenerative conditions of the eye, such as Age-related Macular Degeneration (AMD) and glaucoma share at least in part similar mechanisms of neuronal cell death with those occurring in AD and PD. This review aims to summarize and critically analyze the evidence to date of the effects and potential neuroprotective actions of thymoquinone in the eye and ocular neurodegenerations.

Antioxidants in Alzheimer's Disease: Current Therapeutic Significance and Future Prospects

Alzheimer's disease (AD) rate is accelerating with the increasing aging of the world's population. The World Health Organization (WHO) stated AD as a global health priority. According to the WHO report, around 82 million people in 2030 and 152 million in 2050 will develop dementia (AD contributes 60% to 70% of cases), considering the current scenario. AD is the most common neurodegenerative disease, intensifying impairments in cognition, behavior, and memory. Histopathological AD variations include extracellular senile plaques' formation, tangling of intracellular neurofibrils, and synaptic and neuronal loss in the brain. Multiple evidence directly indicates that oxidative stress participates in an early phase of AD before cytopathology. Moreover, oxidative stress is induced by almost all misfolded protein lumps like α-synuclein, amyloid-β, and others. Oxidative stress plays a crucial role in activating and causing various cell signaling pathways that result in lesion formations of toxic substances, which foster the development of the disease. Antioxidants are widely preferred to combat oxidative stress, and those derived from natural sources, which are often incorporated into dietary habits, can play an important role in delaying the onset as well as reducing the progression of AD. However, this approach has not been extensively explored yet. Moreover, there has been growing evidence that a combination of antioxidants in conjugation with a nutrient-rich diet might be more effective in tackling AD pathogenesis. Thus, considering the above-stated fact, this comprehensive review aims to elaborate the basics of AD and antioxidants, including the vitality of antioxidants in AD. Moreover, this review may help researchers to develop effectively and potentially improved antioxidant therapeutic strategies for this disease as it also deals with the clinical trials in the stated field.

Possible therapeutic effects of Nigella sativa and its thymoquinone on COVID-19

CONTEXT

COVID-19 is a novel coronavirus that causes a severe infection in the respiratory system. Nigella sativa L. (Ranunculaceae) is an annual flowering plant used traditionally as a natural food supplement and multipurpose medicinal agent.

OBJECTIVE

The possible beneficial effects of N. sativa, and its constituent, thymoquinone (TQ) on COVID-19 were reviewed.

METHODS

The key words including, COVID-19, N. sativa, thymoquinone, antiviral effects, anti-inflammatory and immunomodulatory effects in different databases such as Web of Science (ISI), PubMed, Scopus, and Google Scholar were searched from 1990 up to February 2021.

RESULTS

The current literature review showed that N. sativa and TQ reduced the level of pro-inflammatory mediators including, IL-2, IL-4, IL-6, and IL-12, while enhancing IFN-γ. Nigella sativa and TQ increased the serum levels of IgG1 and IgG2a, and improved pulmonary function tests in restrictive respiratory disorders.

DISCUSSION AND CONCLUSIONS

These preliminary data of molecular docking, animal, and clinical studies propose N. sativa and TQ might have beneficial effects on the treatment or control of COVID-19 due to antiviral, anti-inflammatory and immunomodulatory properties as well as bronchodilatory effects. The efficacy of N. sativa and TQ on infected patients with COVID-19 in randomize clinical trials will be suggested.

COVID-19, cytokines, inflammation, and spices: How are they related?

BACKGROUND

Cytokine storm is the exaggerated immune response often observed in viral infections. It is also intimately linked with the progression of COVID-19 disease as well as associated complications and mortality. Therefore, targeting the cytokine storm might help in reducing COVID-19-associated health complications. The number of COVID-19 associated deaths (as of January 15, 2021; https://www.worldometers.info/coronavirus/) in the USA is high (1199/million) as compared to countries like India (110/million). Although the reason behind this is not clear, spices may have some role in explaining this difference. Spices and herbs are used in different traditional medicines, especially in countries such as India to treat various chronic diseases due to their potent antioxidant and anti-inflammatory properties.

AIM

To evaluate the literature available on the anti-inflammatory properties of spices which might prove beneficial in the prevention and treatment of COVID-19 associated cytokine storm.

METHOD

A detailed literature search has been conducted on PubMed for collecting information pertaining to the COVID-19; the history, origin, key structural features, and mechanism of infection of SARS-CoV-2; the repurposed drugs in use for the management of COVID-19, and the anti-inflammatory role of spices to combat COVID-19 associated cytokine storm.

KEY FINDINGS

The literature search resulted in numerous in vitro, in vivo and clinical trials that have reported the potency of spices to exert anti-inflammatory effects by regulating crucial molecular targets for inflammation.

SIGNIFICANCE

As spices are derived from Mother Nature and are inexpensive, they are relatively safer to consume. Therefore, their anti-inflammatory property can be exploited to combat the cytokine storm in COVID-19 patients. This review thus focuses on the current knowledge on the role of spices for the treatment of COVID-19 through suppression of inflammation-linked cytokine storm.

Thymoquinone and Curcumin Defeat Aging-Associated Oxidative Alterations Induced by D-Galactose in Rats' Brain and Heart

D-galactose (D-gal) administration causes oxidative disorder and is widely utilized in aging animal models. Therefore, we subcutaneously injected D-gal at 200 mg/kg BW dose to assess the potential preventive effect of thymoquinone (TQ) and curcumin (Cur) against the oxidative alterations induced by D-gal. Other than the control, vehicle, and D-gal groups, the TQ and Cur treated groups were orally supplemented at 20 mg/kg BW of each alone or combined. TQ and Cur effectively suppressed the oxidative alterations induced by D-gal in brain and heart tissues. The TQ and Cur combination significantly decreased the elevated necrosis in the brain and heart by D-gal. It significantly reduced brain caspase 3, calbindin, and calcium-binding adapter molecule 1 (IBA1), heart caspase 3, and BCL2. Expression of mRNA of the brain and heart TP53, p21, Bax, and CASP-3 were significantly downregulated in the TQ and Cur combination group along with upregulation of BCL2 in comparison with the D-gal group. Data suggested that the TQ and Cur combination is a promising approach in aging prevention.

A qualitative and quantitative comparison of Crocus sativus and Nigella sativa immunomodulatory effects

The present article reviews and compares the immunomodulatory activities of Crocus sativus (C. sativus) and Nigella sativa (N. sativa) and their main bioactive compounds. Immunomodulatory effects of these plants, especially with respect to Th1 and Th2 cytokines, are discussed based on relevant articles, books, and conference papers published in English until the end of April 2020, that were retrieved from Web of Science, PubMed, Scopus and Google Scholar databases. C. sativus and its constituents increase immunoglobulin (Ig-)G, interleukin 2 (IL)-2, interferon gamma (IFN-γ), and IFN-γ/IL-4 ratio, but decreased IgM, IL-10 and IL-4 secretion. N. sativa extract and thymoquinone reduce the levels of IL-2, -4, -10, and -12, while enhance IFN-γ and serum IgG1 and 2a. The reviewed articles indicate that C. sativus and N. sativa and their constituents could be potentially considered promising treatments for disorders associated with immune-dysregulation such as asthma and cancer.

Neuroprotective Natural Products for Alzheimer's Disease

Alzheimer’s disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.

Black Cumin (Nigella sativa L.): A Comprehensive Review on Phytochemistry, Health Benefits, Molecular Pharmacology, and Safety

Mounting evidence support the potential benefits of functional foods or nutraceuticals for human health and diseases. Black cumin (Nigella sativa L.), a highly valued nutraceutical herb with a wide array of health benefits, has attracted growing interest from health-conscious individuals, the scientific community, and pharmaceutical industries. The pleiotropic pharmacological effects of black cumin, and its main bioactive component thymoquinone (TQ), have been manifested by their ability to attenuate oxidative stress and inflammation, and to promote immunity, cell survival, and energy metabolism, which underlie diverse health benefits, including protection against metabolic, cardiovascular, digestive, hepatic, renal, respiratory, reproductive, and neurological disorders, cancer, and so on. Furthermore, black cumin acts as an antidote, mitigating various toxicities and drug-induced side effects. Despite significant advances in pharmacological benefits, this miracle herb and its active components are still far from their clinical application. This review begins with highlighting the research trends in black cumin and revisiting phytochemical profiles. Subsequently, pharmacological attributes and health benefits of black cumin and TQ are critically reviewed. We overview molecular pharmacology to gain insight into the underlying mechanism of health benefits. Issues related to pharmacokinetic herb-drug interactions, drug delivery, and safety are also addressed. Identifying knowledge gaps, our current effort will direct future research to advance potential applications of black cumin and TQ in health and diseases.

Mesenchymal stem cell-conditioned medium attenuates the retinal pathology in amyloid-β-induced rat model of Alzheimer's disease: Underlying mechanisms

Amyloid‐beta (Aβ) oligomer is known to contribute to the pathophysiology of age‐related macular degeneration. Herein, we aimed to elucidate the in vivo and in vitro effects of Aβ_1‐42 application on retinal morphology in rats. Our in vivo studies revealed that intracerebroventricular administration of Aβ_1‐42 oligomer caused dysmorphological changes in both retinal ganglion cells and retinal pigment epithelium. In addition, in vitro studies revealed that ARPE‐19 cells following Aβ_1‐42 oligomer application had decreased viability along with apoptosis and decreased expression of the tight junction proteins, increased expression of both phosphor‐AKT and phosphor‐GSK3β and decreased expression of both SIRT1 and β‐catenin. Application of conditioned medium (CM) obtained from mesenchymal stem cells (MSC) protected against Aβ_1‐42 oligomer‐induced retinal pathology in both rats and ARPE‐19 cells. In order to explore the potential role of peptides secreted from the MSCs, we applied mass spectrometry to compare the peptidomics profiles of the MSC‐CM. Gene ontology enrichment analysis and String analysis were performed to explore the differentially expressed peptides by predicting the functions of their precursor proteins. Bioinformatics analysis showed that 3‐8 out of 155–163 proteins in the MSC‐CM maybe associated with SIRT1/pAKT/pGSK3β/β‐catenin, tight junction proteins, and apoptosis pathway. In particular, the secretomes information on the MSC‐CM may be helpful for the prevention and treatment of retinal pathology in age‐related macular degeneration.

Thymoquinone, as a Novel Therapeutic Candidate of Cancers

To date, natural products are widely used as pharmaceutical agents for many human diseases and cancers. One of the most popular natural products that have been studied for anticancer properties is thymoquinone (TQ). As a bioactive compound of Nigella sativa, TQ has shown anticancer activities through the inhibition of cell proliferation, migration, and invasion. The anticancer efficacy of TQ is being investigated in several human cancers such as pancreatic cancer, breast cancer, colon cancer, hepatic cancer, cervical cancer, and leukemia. Even though TQ induces apoptosis by regulating the expression of pro- apoptotic and anti-apoptotic genes in many cancers, the TQ effect mechanism on such cancers is not yet fully understood. Therefore, the present review has highlighted the TQ effect mechanisms on several signaling pathways and expression of tumor suppressor genes (TSG). Data from relevant published experimental articles on TQ from 2015 to June 2020 were selected by using Google Scholar and PubMed search engines. The present study investigated the effectiveness of TQ alone or in combination with other anticancer therapeutic agents, such as tyrosine kinase inhibitors on cancers, as a future anticancer therapy nominee by using nanotechnology.

TLR4 Targeting as a Promising Therapeutic Strategy for Alzheimer Disease Treatment

Alzheimer disease (AD) is a devastating neurodegenerative disorder characterized by extracellular accumulation of amyloid-beta and formation of intracellular neurofibrillary tangles. Microglia activation and neuroinflammation play important roles in the pathogenesis of AD; Toll-like receptor 4 (TLR4)-a key component of the innate immune system-in microglia is also thought to be involved based on the observed association between TLR gene polymorphisms and AD risk. TLR4 has been shown to exert both detrimental and beneficial effects on AD-related pathologies. In preclinical models, experimental manipulations targeting TLR4 were shown to improve learning and memory, which was related to inhibition of pro-inflammatory cytokine release and reduction of oxidative stress. In this review, we summarize the key evidence supporting TLR4 as a promising therapeutic target in AD treatment.

Evaluation of the effect of thymoquinone in d-galactose-induced memory impairments in rats: Role of MAPK, oxidative stress, and neuroinflammation pathways and telomere length

D-galactose (d-gal) induces aging and memory impairment via oxidative stress and neuroinflammation pathways. This study evaluated the neuroprotective activity of thymoquinone (TQ) against d-gal. d-gal (400 mg/kg, SC), d-gal plus TQ (2.5, 5, 10 mg/kg, i.p.), and TQ alone (2.5 and 10 mg/kg) for 8 weeks were administered to rats. The effect of TQ on learning and memory were studied using the Morris water maze test. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in the hippocampus. The levels of MAPKs (p-ERK/ERK, p-P38/P38), cAMP response elements binding (p-CREB/CREB), advanced glycation end products (AGEs), inflammatory markers (TNFα, IL-1β), glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF) were analyzed by western blotting. Telomere length was evaluated using real-time PCR. Memory and learning impairment, MDA enhancement, GSH reduction, and neuroinflammation via increasing the TNFα, IL-1β, and GFAP contents were observed in d-gal group. TQ with d-gal, improved memory impairment, reduced oxidative stress, and alleviated neuroinflammation. The elevated level of AGEs decreased by TQ compared to d-gal. No changes were observed in the levels of p-ERK/ERK, p-CREB/CREB, p-P38/P38, BDNF, and telomere length following administration of d-gal or TQ plus d-gal. TQ improved memory deficits of d-gal through anti-oxidative and anti-inflammatory mechanisms.

Effects of Nigella sativa oil and thymoquinone against bisphenol A-induced metabolic disorder in rats

The underlying mechanisms of bisphenol A (BPA)-induced metabolic disorder and the protective impact of Nigella sativa oil (NSO) and thymoquinone (TQ) against BPA-induced metabolic disorder were investigated. Rats were treated as follows: Control, BPA (10 mg/kg), TQ (2 mg/kg), NSO (84 μL/kg), BPA + TQ (0.5, 1, 2 mg/kg), and BPA + NSO (21, 42, 84 μL/kg). BPA was administered by gavage, while, TQ and NSO were injected intraperitoneally (daily, 54 days). The weight, blood pressure, serum parameters [glucose, lipid profile, hepatic enzymes, insulin, interlukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), leptin, adiponectin], malondialdehyde (MDA), glutathione (GSH) and insulin signaling pathways [insulin receptor substrate (p-IRS,IRS); kinase (p-Akt,Akt); glycogen synthase kinase (p-GS3K,GS3K)] were measured. BPA increased the blood pressure, MDA, lipid profile, hepatic enzymes, insulin, IL-6, TNF-α, and leptin, and decreased the GSH and phosphorylated forms of IRS, Akt, GS3K but did not alter weight, glucose, IRS, AKT, and GS3K in the liver. Administration of NSO or TQ with BPA reduced the blood pressure, liver level of MDA, lipid profile, hepatic enzymes, insulin, IL-6, TNF-α, leptin, and increased the liver level of GSH and p-IRS, p-AKT, p-GS3K. TQ and NSO are thought to be effective in controlling metabolic disorders induced by BPA.

Thymoquinone administration ameliorates Alzheimer's disease-like phenotype by promoting cell survival in the hippocampus of amyloid beta1-42 infused rat model

BACKGROUND

Thymoquinone (TQ), a biologically active ingredient of Nigella sativa, has anti-inflammatory, anti-oxidative and neuroprotective properties. Therefore, it could be a good candidate in the recovery of Alzheimer`s disease (AD) pathology rather than current symptomatic reliefs.

PURPOSE

In the present study, we examined the molecular healing effects of TQ in amyloid beta 1-42 (Aβ_1-42) peptide-infused AD rat hippocampus.

STUDY DESIGN

A micro-osmotic pump containing aggregated Aβ_1-42 was cannulated into the hippocampus of adult female rats. After two weeks infusion, the dose of TQ (10 mg/kg or 20 mg/kg) was determined according to the HPLC results of cerebrospinal fluid and TQ was given to rats intragastrically for 15 days.

METHODS

The memory performance of rats was determined by Morris water maze test. Afterwards, the acetylcholinesterase (AChE) level were measured by ELISA. Histopathological examinations of hippocampal tissue were performed for cell survival by Nissl staining, for detection of amyloid plaque deposits by Congo red staining and for determination of degenerating neurons by Fluoro Jade C staining. MicroRNA/mRNA levels and protein expressions of AD-related genes and proteins were analyzed by Real-Time Polymerase Chain Reaction and Western Blotting, respectively.

RESULTS

Administration of TQ enhanced the memory performance of Aβ_1-42 infused rats and it also ameliorated the neuronal loss in the cornu ammonis (CA1), but not in the dentate gyrus (DG). In addition, TQ treatment decreased the fibril deposition whose accumulation was significantly higher in the Aβ_1-42-infused animals compared to that of the control group. The expression profiles of mir29c and Bax which significantly upregulated in the Aβ_1-42-infused animals were attenuated by TQ. Furthermore, administration of TQ decreased the expressions of Aβ, phosphorylated-tau, and BACE-1 proteins. There was no significant therapeutic effect of TQ on the AKT/GSK3β or MAPK signaling pathways which were affected due to Aβ_1-42 infusion.

CONCLUSION

TQ has the capacity to recover the neuropathology by removing Aβ plaques and by restoring neuron viability. All might have established the molecular basement of the consolidation in the memory observed by means of TQ treatment.

Dual prophylactic/therapeutic potential of date seed, and nigella and olive oils-based nutraceutical formulation in rats with experimentally-induced Alzheimer's disease: A mechanistic insight

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with a multifactorial etiology and significantly increasing incidence during the last decade. Hence, developing an effective therapy is crucial for public health. The current study aimed to examine the dual prophylactic/therapeutic potential of a nutraceutical formula based on aqueous extract of roasted date seeds, and nigella and virgin-olive oils against experimentally-induced Alzheimer's disease in rats. Alzheimer's disease-like pathology was induced in male Wistar rats using oral CuSO₄ (200 mg/Kg/day for two months). The nutraceutical formula was given orally to experimental animals (10 mL/kg/d) for 14 days before (as prophylaxis) and after Alzheimer's disease induction and its therapeutic effect in both cases is tested in comparison to donepezil (0.5 mg/kg/d). The nutraceutical formula was found to ameliorate the CuSO₄-induced neuronal damage and regenerate the affected hippocampus tissue and significantly improvemed in learning ability. The formula was also effective in decreasing brain amyloid-β, tau protein, TNF-α level, iNOS level in hippocampus, oxidative stress level, and inhibiting acetylcholinesterase activity and expression in brain and hippocampus, respectively. Further, an increase in GSH levels, activities of SOD, and GST and levels of hippocampus ADAM 17 and brain phospholipids was observed. In conclusion, the studied nutraceutical formula is proved to be effective in ameliorating Alzheimer's neurodegenerative progression with added-prophylactic potential.

Alzheimer's disease: natural products as inhibitors of neuroinflammation

Alzheimer’s disease (AD) is the most common form of dementia and affects 44 million people worldwide. New emerging evidence from pre-clinical and clinical investigations shows that neuroinflammation is a major pathological component of AD suggesting that anti-inflammatory strategies are important in delaying the onset or slowing the progression of the disease. However, efforts to employ current anti-inflammatory agents in AD clinical trials have produced limited success. Consequently, there is a need to explore anti-inflammatory natural products, which target neuroinflammatory pathways relevant to AD pathogenesis. This review summarises important druggable molecular targets of neuroinflammation and presents classes of anti-neuroinflammatory natural products with potentials for preventing and reducing symptoms of AD.

Thymoquinone (Tq) protects necroptosis induced by autophagy/mitophagy-dependent oxidative stress in human bronchial epithelial cells exposed to cigarette smoke extract (CSE)

Chronic obstructive pulmonary disease (COPD) is characterized by cigarette smoke-induced emphysema. Herein, we demonstrate protective effects of Thymoquinone (Tq), an active constituent from Nigella sativa, against cigarette smoke extract (CSE)-induced abnormalities in bronchial epithelial cells. Dose-dependent reduction in cell viability was observed in BEAS-2B cells when exposed to different CSE concentrations, which was significantly reversed by Tq evident by LDH release. Levels of SOD, CAT, G_R , GSH, and mitochondrial membrane ATPases were significantly reduced upon CSE exposure, an event, again, antagonized in presence of Tq. Similarly, Tq treatment significantly blocked CSE-induced 4HNE elevations. Further, Tq-improved mitochondrial dysfunction caused by CSE and significantly decreased autophagy/mitophagy markers like LC3II and p-Drp. Tq also reduced necroptosis markers such as p-MLKL, RIP-1, and RIP-3, by stabilizing PINK-1 levels. In summary, Tq possesses protective properties against human bronchial epithelial cell autophagy/mitophagy-dependent necroptosis caused by CSE, which warrants considerable attention for further preclinical evaluations. PRACTICAL APPLICATIONS: This study demonstrates Thymoquinone (Tq), a natural plant extract to possess protective properties against human bronchial epithelial cell autophagy/mitophagy-dependent necroptosis caused by cigarette smoke extract. The demonstrated efficacy of Tq will throw light for further preclinical evaluation of this molecule in CSE-mediated complications. A detailed in vivo research is recommended.

Lipids Nutrients in Parkinson and Alzheimer's Diseases: Cell Death and Cytoprotection

Neurodegenerative diseases, particularly Parkinson’s and Alzheimer’s, have common features: protein accumulation, cell death with mitochondrial involvement and oxidative stress. Patients are treated to cure the symptoms, but the treatments do not target the causes; so, the disease is not stopped. It is interesting to look at the side of nutrition which could help prevent the first signs of the disease or slow its progression in addition to existing therapeutic strategies. Lipids, whether in the form of vegetable or animal oils or in the form of fatty acids, could be incorporated into diets with the aim of preventing neurodegenerative diseases. These different lipids can inhibit the cytotoxicity induced during the pathology, whether at the level of mitochondria, oxidative stress or apoptosis and inflammation. The conclusions of the various studies cited are oriented towards the preventive use of oils or fatty acids. The future of these lipids that can be used in therapy/prevention will undoubtedly involve a better delivery to the body and to the brain by utilizing lipid encapsulation.

Thymoquinone attenuates IgE-mediated allergic response via pi3k-Akt-NFκB pathway and upregulation of the Nrf2-HO1 axis

IgE-dependent reactions mediate the majority of allergic diseases. This study explores the effects of thymoquinone (Tq) on IgE-mediated allergic response in activated mast cells, basophils, and neutrophils. Tq treatment resulted in a dose-dependent decrease in levels of TNF-α and IL-4 in activated RBL-2H3 cells. Tq inhibited the degranulation of these cells with an IC₅₀ value of 56.37 µM. Moreover, the compound suppressed basophil activation induced through FcεRI receptors with an IC₅₀ value of 45.76 µM in heparinized human whole blood. Likewise, neutrophil migration and elastase activity were dose-dependently reduced. While Tq decreased the phosphorylation of Akt and NFκB in activated RBL-2H3 cells, it increased nuclear Nrf2 and HO-1 antioxidant proteins. Our results indicate that Tq possesses demonstrable activity in cellular models of IgE-mediated allergic reactions. PRACTICAL APPLICATIONS: The current study sheds light on the mechanistic pathways of Tq on IgE-based response in activated mast cells, basophils, and neutrophils. The output of this preclinical in vitro study may be translated into better chemotherapeutic applications of Tq and its analogs in the treatment of allergic inflammation. However, a detailed investigation of in vivo models is recommended.

Non-polyphenolic natural inhibitors of amyloid aggregation

Protein misfolding diseases (PMDs) are chronic and progressive, with no effective therapy so far. Aggregation and misfolding of amyloidogenic proteins are closely associated with the onset and progression of PMDs, such as amyloid-β (Aβ) in Alzheimer's disease, α-Synuclein (α-Syn) in Parkinson's disease and human islet amyloid polypeptide (hIAPP) in type 2 diabetes. Inhibiting toxic aggregation of amyloidogenic proteins is regarded as a promising therapeutic approach in PMDs. The past decade has witnessed the rapid progresses of this field, dozens of inhibitors have been screened and verified in vitro and in vivo, demonstrating inhibitory effects against the aggregation and misfolding of amyloidogenic proteins, together with beneficial effects. Natural products are major sources of small molecule amyloid inhibitors, a number of natural derived compounds have been identified with great bioactivities and translational prospects. Here, we review the non-polyphenolic natural inhibitors that potentially applicable for PMDs treatment, along with their working mechanisms. Future directions are proposed for the development and clinical applications of these inhibitors.

Piperine Enhances the Antioxidant and Anti-Inflammatory Activities of Thymoquinone against Microcystin-LR-Induced Hepatotoxicity and Neurotoxicity in Mice

Microcystin- (MC-) LR is the most frequent cyanotoxin produced by Microcystis aeruginosa cyanobacteria in the contaminated freshwater environment. MC represents a health hazard to humans and animals. Therefore, the present study was designed to evaluate the potential ameliorative effect of thymoquinone (TQ) and/or piperine (PP) against MC toxicity in mice. Fifty-six mice were randomly divided into seven experimental groups. Group I is the normal control that received distilled water for 21 days; Group II (TQ) was treated with TQ (10 mg/kg, i.p) for 21 days; Group III (PP) was treated with PP (25 mg/kg, i.p) for 21 days; Group IV (MC) was treated with MC (10 μg/kg, i.p) for 14 days and served as the toxic control; and Groups V, VI, and VII received TQ and/or PP 7 days prior to MC and continued for 14 days with MC. The results revealed that MC elicited hepatotoxicity and neurotoxicity which was evident due to the significant elevation of serum AST, ALT, γGT, ALP, LDH, IL-1β, IL-6, and TNF-α levels. Furthermore, MC markedly increased MDA and NO contents along with reduction of GSH, SOD, CAT, and GSH-Px in liver and brain tissues. The electron transport chain may be a possible target for MC. TQ and/or PP ameliorated the MC-mediated oxidative damage in the liver and brain which might be attributed to their antioxidant properties. However, the concurrent treatment of TQ and PP showed the best regimen as a result of the PP-enhanced bioavailability of TQ.

Alpha lipoic acid and metformin alleviates experimentally induced insulin resistance and cognitive deficit by modulation of TLR2 signalling

BACKGROUND

Obesity is commonly found to be co-morbid with type 2 Diabetes Mellitus. In obese diabetic patients, TLR-2 receptor induced inflammation leads to the development of insulin resistance (IR). Furthermore, the IR is considered to be the most important cause for promoting cognitive decline which is evident in brain of patients with Alzheimer's disease related dementia (ADRD).

METHODS

In this study, the effect of α-lipoic acid (ALA) has been examined in rodent model of zymosan induced insulin resistance and cognitive deficits, targeting at TLR-2 signalling. TLR-2 agonist, Zymosan initiates inflammatory cascade, resulting in IR and cognitive dysfunction. Zymosan (50 mg/kg ip) was given to mice on 1st, 8th, 15th and 22nd day to induce IR which was confirmed by hyperglycaemia, hyperinsulinemia, hyperlipidimea, increased glycated haemoglobin and HOMA-IR. Further the cognitive performance was assessed in Morris water maze revealing cognitive deficit in zymosan treated mice.

RESULTS

Daily treatment with ALA for 28 days (50, 100, 200 mg/kg, ip) significantly improved insulin sensitivity and cognitive performance in mice by decreasing insulin resistance, corticosterone, IL-6 levels, acetylcholinesterase enzyme activity and oxidative stress in liver, cortex and hippocampus. ALA also increased adiponectin level and reduced body weight. Combination of ALA (100 mg/kg, ip) with metformin (100 mg/kg, ip) exhibited a potentiating effect in improving cognitive performance and insulin signalling.

CONCLUSION

The findings of the study supported the hypothesis that TLR-2 induced inflammation leads to insulin resistance and cognitive impairment and provides an evidence for the therapeutic effect of ALA in IR and ADRD patients.

Protective Roles of Thymoquinone Nanoformulations: Potential Nanonutraceuticals in Human Diseases

The focus on nanotechnology for improved bioavailability and drug delivery is of increasing importance for control of different human diseases. Therefore, numerous nanoformulations have been developed for the oral bioavailability of different drugs. This review introduces applications of nanomedicine to enhance the biological activities of thymoquinone (TQ) to control different diseases in several in vivo studies as a preliminary investigation for human disease treatment with nano-TQ. Nano-TQ effectively augments the anticancer roles of doxorubicin by upregulation of P53 and downregulation of Bcl2 and potentiates paclitaxel's apoptosis in MCF-7 breast cancer cells. Moreover, nano-TQ protects against diabetes, inflammation, CNS, and hepatotoxicity, mainly by enhancement of organs' antioxidant status. We summarize the pros and cons of several FDA approved nanoparticle-based therapeutics and discuss the roadblocks in clinical translation, along with potential nano-TQ strategies to overcome these roadblocks. From this review, we can conclude that nano-TQ may be considered as a promising nutraceutical for human health.