6-Shogaol has anti-amyloidogenic activity and ameliorates Alzheimer’s disease via CysLT1R-mediated inhibition of cathepsin B

An overview of 6-shogaol: new insights into its pharmacological properties and potential therapeutic activities

Ginger (Zingiber officinale Roscoe) has traditionally been used as a cooking spice and herbal medicine for treating nausea and vomiting. More recently, ginger was found to effectively reduce the risk of diseases such as gastroenteritis, migraine, gonarthritis, etc., due to its various bioactive compounds. 6-Shogaol, the pungent phenolic substance in ginger, is the most pharmacologically active among such compounds. The aim of the present study was to review the pharmacological characteristic of 6-shogaol, including the properties of anti-inflammatory, antioxidant and antitumour, and its corresponding molecular mechanism. With its multiple mechanisms, 6-shogaol is considered a beneficial natural compound, and therefore, this review will shed some light on the therapeutic role of 6-shogaol and provide a theoretical basis for the development and clinical application of 6-shogaol.

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.

Exploiting Natural Niches with Neuroprotective Properties: A Comprehensive Review

Natural products from mushrooms, plants, microalgae, and cyanobacteria have been intensively explored and studied for their preventive or therapeutic potential. Among age-related pathologies, neurodegenerative diseases (such as Alzheimer's and Parkinson's diseases) represent a worldwide health and social problem. Since several pathological mechanisms are associated with neurodegeneration, promising strategies against neurodegenerative diseases are aimed to target multiple processes. These approaches usually avoid premature cell death and the loss of function of damaged neurons. This review focuses attention on the preventive and therapeutic potential of several compounds derived from natural sources, which could be exploited for their neuroprotective effect. Curcumin, resveratrol, ergothioneine, and phycocyanin are presented as examples of successful approaches, with a special focus on possible strategies to improve their delivery to the brain.

Comparative proteomic analysis of cerebral cortex revealed neuroprotective mechanism of esculentoside A on Alzheimer's disease

Esculentoside A (EsA), isolated from phytolacca esculenta, is a saponin showing neuroprotective effect in the mouse models of Alzheimer's disease (AD). To investigate its action target and underlying mechanism, this study used the proteomics technique of isobaric tags for relative and absolute quantification (iTRAQ) to analyze the differentially expressed proteins (DEPs) in the cerebral cortex of EsA-treated and untreated triple-transgenic 3 × Tg-AD model mice. Proteomic comparison revealed 250, 436, and 903 DEPs in three group pairs, i.e. AD/Wild-type (WT), AD+5 mg/kg EsA/AD, AD+10 mg/kg EsA/AD, respectively. Among them 28 DEPs were commonly shared by three group pairs, and 25 of them showed reversed expression levels in the diseased group under the treatment of both doses of EsA. Bioinformatics analysis revealed that these DEPs were mainly linked to metabolism, synapses, apoptosis, learning and memory. EsA treatment restored the expression of these proteins, including amyloid precursor protein (APP), cathepsin B (Cstb), 4-aminobutyrate aminotransferase (Abat), 3-phosphoinositide-dependent protein kinase-1 (PDK1), carnitine palmitoyltransferase1 (Cpt1) and synaptotagmin 17 (Syt17), thereby ameliorated the spatial learning and memory of AD mice. Collectively, this study reveals for the first time the profound effect of EsA on the cerebral cortex of AD mice, which might be a potential therapeutic agent for the treatment of AD.

Suppression of Inflamm-Aging by Moringa oleifera and Zingiber officinale Roscoe in the Prevention of Degenerative Diseases: A Review of Current Evidence

Inflammation or inflamm-aging is a chronic low-grade inflammation that contributes to numerous types of degenerative diseases among the elderly and might be impeded by introducing an anti-inflammatory agent like Moringa oleifera Lam (moringa) and Zingiber officinale Roscoe (ginger). Therefore, this paper aims to review the role of moringa and ginger in suppressing inflamm-aging to prevent degenerative diseases. Various peer-reviewed publications were searched and downloaded using the reputed search engine "Pubmed" and "Google Scholar". These materials were reviewed and tabulated. A comparison between these previous findings was made based on the mechanism of action of moringa and ginger against degenerative diseases, focusing on their anti-inflammatory properties. Many studies have reported the efficacy of moringa and ginger in type 2 diabetes mellitus, neurodegenerative disease, cardiovascular disease, cancer, and kidney disease by reducing inflammatory cytokines activities, mainly of TNF-α and IL-6. They also enhanced the activity of antioxidant enzymes, including catalase, glutathione, and superoxide dismutase. The anti-inflammatory activities can be seen by inhibiting NF-κβ activity. Thus, the anti-inflammatory potential of moringa and ginger in various types of degenerative diseases due to inflamm-aging has been shown in many recent types of research.

Phytochemicals: A Promising Alternative for the Prevention of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that worsens with ageing and affects memory and cognitive function. Presently more than 55 million individuals are affected by AD all over the world, and it is a leading cause of death in old age. The main purpose of this paper is to review the phytochemical constituents of different plants that are used for the treatment of AD. A thorough and organized review of the existing literature was conducted, and the data under the different sections were found using a computerized bibliographic search through the use of databases such as PubMed, Web of Science, Google Scholar, Scopus, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS, and numerous other websites. Around 360 papers were screened, and, out of that, 258 papers were selected on the basis of keywords and relevant information that needed to be included in this review. A total of 55 plants belonging to different families have been reported to possess different bioactive compounds (galantamine, curcumin, silymarin, and many more) that play a significant role in the treatment of AD. These plants possess anti-inflammatory, antioxidant, anticholinesterase, and anti-amyloid properties and are safe for consumption. This paper focuses on the taxonomic details of the plants, the mode of action of their phytochemicals, their safety, future prospects, limitations, and sustainability criteria for the effective treatment of AD.

Antioxidant Compounds in the Treatment of Alzheimer's Disease: Natural, Hybrid, and Synthetic Products

Alzheimer's disease (AD) which is associated with cognitive dysfunction and memory lapse has become a health concern. Various targets and pathways have been involved in AD's progress, such as deficit of acetylcholine (ACh), oxidative stress, inflammation, β-amyloid (Aβ) deposits, and biometal dyshomeostasis. Multiple pieces of evidence indicate that stress oxidative participation in an early stage of AD and the generated ROS could enable neurodegenerative disease leading to neuronal cell death. Hence, antioxidant therapies are applied in treating AD as a beneficial strategy. This review refers to the development and use of antioxidant compounds based on natural products, hybrid designs, and synthetic compounds. The results of using these antioxidant compounds were discussed with the given examples, and future directions for the development of antioxidants were evaluated.

Leukotrienes vs. Montelukast—Activity, Metabolism, and Toxicity Hints for Repurposing

Increasing environmental distress is associated with a growing asthma incidence; no treatments are available but montelukast (MTK)—an antagonist of the cysteinyl leukotrienes receptor 1—is widely used in the management of symptoms among adults and children. Recently, new molecular targets have been identified and MTK has been proposed for repurposing in other therapeutic applications, with several ongoing clinical trials. The proposed applications include neuroinflammation control, which could be explored in some neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases (AD and PD). However, this drug has been associated with an increasing number of reported neuropsychiatric adverse drug reactions (ADRs). Besides, and despite being on the market since 1998, MTK metabolism is still poorly understood and the mechanisms underlying neuropsychiatric ADRs remain unknown. We review the role of MTK as a modulator of leukotriene pathways and systematize the current knowledge about MTK metabolism. Known toxic effects of MTK are discussed, and repurposing applications are presented comprehensively, with a focus on AD and PD.

Medha Plus - A novel polyherbal formulation ameliorates cognitive behaviors and disease pathology in models of Alzheimer's disease

Alzheimer's disease (AD) is a multi-faceted neurodegenerative disorder that leads to drastic cognitive impairments culminating in death. Pathologically, it is characterized by amyloid-β (Aβ) plaques, neurofibrillary tangles and neurodegeneration in brain. Complete cure of AD remains elusive to date. Available synthetic drugs only provide symptomatic reliefs targeting single molecule, hence, are unable to address the multi-factorial aspects in AD pathogenesis. It is imperative to develop combinatorial drugs that address the multiple molecular targets in AD. We show a unique polyherbal formulation of Brahmi, Mandukaparni, Shankhpushpi, Yastimadhu, Kokilaksha and Shunthi called 'Medha Plus' (MP), conventionally used for improving memory and reducing anxiety, was able to ameliorate cognitive deficits and associated pathological hallmarks of AD. Viability assays revealed that MP prevented Aβ-induced loss of neurites as well as neuronal apoptosis in cellular models. An array of behavioral studies showed that MP was able to recover AD-associated memory deficits in both Aβ-injected rats and 5XFAD mice. Immunohistochemical studies further revealed that MP treatment reduced Aβ depositshpi and decreased apoptotic cell death in the hippocampus. Enzymatic assays demonstrated anti-oxidative and anti-acetyl cholinesterase properties of MP especially in hippocampus of Aβ-injected rats. An underlying improvement in synaptic plasticity was observed with MP treatment in 5XFAD mice along with an increased expression of phospho-Akt at serine 473 indicating a role of PI3K/Akt signaling in correcting these synaptic deficits. Thus, our strong experiment-driven approach shows that MP is an incredible combinatorial drug that targets multiple molecular targets with exemplary neuroprotective properties and is proposed for clinical trial.

Ginger for Healthy Ageing: A Systematic Review on Current Evidence of Its Antioxidant, Anti-Inflammatory, and Anticancer Properties

The world's population is ageing at an accelerated pace. Ageing is a natural, physiological but highly complex and multifactorial process that all species in the Tree of Life experience over time. Physical and mental disabilities, and age-related diseases, would increase along with the increasing life expectancy. Ginger (Zingiber officinale) is a plant that belongs to the Zingiberaceae family, native to Southeast Asia. For hundreds of years, ginger has been consumed in various ways by the natives of Asian countries, both as culinary and medicinal herb for the treatment of many diseases. Mounting evidence suggests that ginger can promote healthy ageing, reduce morbidity, and prolong healthy lifespan. Ginger, a well-known natural product, has been demonstrated to possess antioxidant, anti-inflammatory, anticancer, and antimicrobial properties, as well as an outstanding antiviral activity due to a high concentration of antiviral compounds. In this review, the current evidence on the potential role of ginger and its active compounds in the prevention of ageing is discussed.

Ginger, a Possible Candidate for the Treatment of Dementias?

As the human life expectancy increases, age-linked diseases have become more and more frequent. The worldwide increment of dementia cases demands medical solutions, but the current available drugs do not meet all the expectations. Recently the attention of the scientific community was attracted by natural compounds, used in ancient medicine, known for their beneficial effects and high tolerability. This review is focused on Ginger (Zingiber officinale) and explore its properties against Alzheimer's Disease and Vascular Dementia, two of the most common and devastating forms of dementia. This work resumes the beneficial effects of Ginger compounds, tested in computational in vitro and in vivo models of Alzheimer's Disease and Vascular Dementia, along with some human tests. All these evidences suggest a potential role of the compounds of ginger not only in the treatment of the disease, but also in its prevention.

Zingiberis Rhizoma Recens: A Review of Its Traditional Uses, Phytochemistry, Pharmacology, and Toxicology

Zingiberis Rhizoma Recens (ZRR, the fresh rhizoma of Zingiber officinale Roscoe) is a widely used traditional Chinese medicine (TCM). It is also a traditional spice, widely used around the world. The present paper reviews advances in research relating to the botany, ethnopharmacology, phytochemistry, pharmacology, and toxicology of Zingiberis Rhizoma Recens. In addition, this review also discusses some significant issues and the potential direction of future research on Zingiberis Rhizoma Recens. More than 100 chemical compounds have been isolated from Zingiberis Rhizoma Recens, including gingerols, essential oils, diarylheptanoids, and other compounds. Modern studies have confirmed that Zingiberis Rhizoma Recens has pharmacological effects on the nervous system and cardiovascular and cerebrovascular systems, as well as antiemetic, antibacterial, antitumor, anti-inflammatory, and antioxidant effects. However, the modern studies of Zingiberis Rhizoma Recens are still not complete and more bioactive components and potential pharmacological effects need to be explored in the future. There is no unified standard to evaluate the quality and clinical efficacy of Zingiberis Rhizoma Recens. Therefore, we should establish reasonable, accurate, and reliable quality control standards to make better use of Zingiberis Rhizoma Recens.

Ginger (Zingiber officinale Rosc.) and its bioactive components are potential resources for health beneficial agents

Zingiber officinale Rosc. (Zingiberacae), commonly known as ginger, is a perennial and herbaceous plant with long cultivation history. Ginger rhizome is one of the most popular food spices with unique pungent flavor and is prescribed as a well-known traditional Chinese herbal medicine. To date, over 160 constituents, including volatile oil, gingerol analogues, diarylheptanoids, phenylalkanoids, sulfonates, steroids, and monoterpenoid glycosides compounds, have been isolated and identified from ginger. Increasing evidence has revealed that ginger possesses a broad range of biological activities, especially gastrointestinal-protective, anti-cancer, and obesity-preventive effects. In addition, gingerol analogues such as 6-gingerol and 6-shogaol can be rapidly eliminated in the serum and detected as glucuronide and sulfate conjugates. Structural variation would be useful to improve the metabolic characteristics and bioactivities of lead compounds derived from ginger. Furthermore, some clinical trials have indicated that ginger can be consumed for attenuating nausea and vomiting during early pregnancy; however, there is not sufficient data available to rule out its potential toxicity, which should be monitored especially over longer periods. This review provides an up-to-date understanding of the scientific evidence on the development of ginger and its active compounds as health beneficial agents in future clinical trials.

Zingiber officinale ameliorates Alzheimer's disease and Cognitive Impairments: Lessons from preclinical studies

Alzheimer's disease (AD) is a neurodegenerative condition mostly communal in people of advanced years accompanying various dysfunctionalities especially cognitive impairments. A number of cellular damages, such as amyloid-beta aggregation, tau protein hyperphosphorylation, some neurotransmitter imbalances, apoptosis, oxidative stress, and inflammatory responses are responsible for AD incidence. As a reason for inadequate efficacy, side effects, and pharmacokinetic problems of conventional drugs used for AD, the discovery of novel therapeutic agents with multi-targeted potential is desirable. Protective properties of phytochemicals combat numerous diseases and their vast acceptance and demand in human beings encouraged scientists to assess their effective activities. Zingiber officinale, gingerol, shogaol, and borneol were evaluated against memory impairments. Online databases including; Web of Science, Scopus, Embase, Pubmed, ProQuest, ScienceDirect, and Cochrane Library were searched until 3th February 2020. In vitro, in vivo, and clinical studies are included after screening their eligibility. Mostly interventive mechanisms such as; oxidative stress, neuroinflammation, and apoptosis are described. Correlation between the pathogenesis of AD and signaling pathways is explicated. Results and scores of cognition measurements are clarified due to in vivo studies and clinical trials. Some traditional aspects of consuming ginger in AD are also mentioned in the present review. In accumulation ginger and its components possess great potency for improving and abrogating memory dysfunctions but conducting further studies to evaluate their pharmacological and pharmaceutical aspects is required.

Self-assembly of N-terminal Alzheimer's β-amyloid and its inhibition

Peptide sequence modulates amyloid fibril formation and triggers Alzheimer's disease. The N-terminal region of amyloid peptide is disordered and lack any specific secondary structure. An ionic interaction of Aβ_1-11 with factor XII is critical for the activation of the contact system in Alzheimer's disease. In this study, we report the self-assembly of fluctuating N-terminal Aβ_1-11 into nanotubes using atomic force micrography, transmission electron microscopy, circular dichroism studies and molecular modeling studies. The effect of four polyphenols: baicalein, rutin, vanillin and cyanidin-3-O-glucoside (C3G) was also explored on the amyloid fibril inhibitor perspective using amyloid specific dye Thioflavin T (ThT). AFM micrographs suggested the self-assembly of Aβ_1-11 into nanotubes after three weeks of incubation. Microwave treatment results in the conformational variation of disordered structure to β-sheet rich amyloid fibrils. The presence of salts (sodium and potassium chloride) induces the structural transformation of Aβ_1-11 to super-helix. Fluorescence spectroscopy studies using ThT suggested differential inhibition of amyloid fibrils formation in the presence of polyphenols. Molecular modeling studies suggested that binding of polyphenols to Aβ_1-11 through hydrophobic interaction (Phe4 and Tyr 10) and hydrogen bonding (Glu3 and Arg5) play a substantial role in stabilizing Aβ_1-11-polyphenols complex. In the presence of polyphenols, Aβ_1-11 transforms to hybrid nanostructures thus hindering amyloid fibril formation. These results provide structural insights and importance of the N-terminal residues in the Aβ_1-42 self-assembly mechanism.

Benzo(a)pyrene exposure induced neuronal loss, plaque deposition, and cognitive decline in APP/PS1 mice

Background

Exposure to benzo(a)pyrene (BaP) was associated with cognitive impairments and some Alzheimer’s disease (AD)-like pathological changes. However, it is largely unknown whether BaP exposure participates in the disease progression of AD.

Objectives

To investigate the effect of BaP exposure on AD progression and its underlying mechanisms.

Methods

BaP or vehicle was administered to 4-month-old APPswe/PS1dE9 transgenic (APP/PS1) mice and wildtype (WT) mice for 2 months. Learning and memory ability and exploratory behaviors were evaluated 1 month after the initiation/termination of BaP exposure. AD-like pathological and biochemical alterations were examined 1 month after 2-month BaP exposure. Levels of soluble beta-amyloid (Aβ) oligomers and the number of Aβ plaques in the cortex and the hippocampus were quantified. Gene expression profiling was used to evaluate alternation of genes/pathways associated with AD onset and progression. Immunohistochemistry and Western blot were used to demonstrate neuronal loss and neuroinflammation in the cortex and the hippocampus. Treatment of primary neuron-glia cultures with aged Aβ (a mixture of monomers, oligomers, and fibrils) and/or BaP was used to investigate mechanisms by which BaP enhanced Aβ-induced neurodegeneration.

Results

BaP exposure induced progressive decline in spatial learning/memory and exploratory behaviors in APP/PS1 mice and WT mice, and APP/PS1 mice showed severer behavioral deficits than WT mice. Moreover, BaP exposure promoted neuronal loss, Aβ burden and Aβ plaque formation in APP/PS1 mice, but not in WT mice. Gene expression profiling showed most robust alteration in genes and pathways related to inflammation and immunoregulatory process, Aβ secretion and degradation, and synaptic formation in WT and APP/PS1 mice after BaP exposure. Consistently, the cortex and the hippocampus of WT and APP/PS1 mice displayed activation of microglia and astroglia and upregulation of inducible nitric oxide synthase (iNOS), glial fibrillary acidic protein (GFAP), and NADPH oxidase (three widely used neuroinflammatory markers) after BaP exposure. Furthermore, BaP exposure aggravated neurodegeneration induced by aged Aβ peptide in primary neuron-glia cultures through enhancing NADPH oxidase-derived oxidative stress.

Conclusion

Our study showed that chronic exposure to environmental pollutant BaP induced, accelerated, and exacerbated the progression of AD, in which elevated neuroinflammation and NADPH oxidase-derived oxidative insults were key pathogenic events.

5-lipoxygenase pathway and its downstream cysteinyl leukotrienes as potential therapeutic targets for Alzheimer's disease

5-lipoxygenase (ALOX5) is an enzyme involved in arachidonic acid (AA) metabolism, a metabolic pathway in which cysteinyl leukotrienes (CysLTs) are the resultant metabolites. Both ALOX5 and CysLTs are clinically significant in a number of inflammatory diseases, such as in asthma and allergic rhinitis, and drugs antagonizing the effect of these molecules have long been successfully used to counter these diseases. Interestingly, recent advances in 'neuroinflammation' research has led to the discovery of several novel inflammatory pathways regulating many cerebral pathologies, including the ALOX5 pathway. By means of pharmacological and genetic studies, both ALOX5 and CysLTs receptors have been shown to be involved in the pathogenesis of Alzheimer's disease (AD) and other neurodegenerative/neurological diseases, such as in Parkinson's disease, multiple sclerosis, and epilepsy. In both transgenic and sporadic models of AD, it has been shown that the levels of ALOX5/CysLTs are elevated, and that genetic/pharmacological interventions of these molecules can alleviate AD-related behavioral and pathological conditions. Clinical relevance of these molecules has also been found in AD brain samples. In this review, we aim to summarize such important findings on the role of ALOX5/CysLTs in AD pathophysiology, from both the cellular and the molecular aspects, and also discuss the potential of their blockers as possible therapeutic choices to curb AD-related conditions.

Modulation of neuroinflammation by cysteinyl leukotriene 1 and 2 receptors: implications for cerebral ischemia and neurodegenerative diseases

Neuroinflammation is a complex biological process and has been known to play an important role in age-related cerebrovascular and neurodegenerative disorders, such as cerebral ischemia, Alzheimer's disease, and Parkinson's disease. Cysteinyl leukotrienes (CysLTs) are potent inflammatory lipid mediators that exhibit actions mainly through activating type 1 and type 2 CysLT receptors (CysLT1 and CysLT2). Accumulating evidence shows that CysLT1 and CysLT2 are activated at different stages of pathological process in various cell types in the brain such as vascular endothelial cells, astrocytes, microglia, and neurons in response to insults. However, the precise roles and mechanisms of CysLT1 and CysLT2 in regulating the pathogenesis of cerebral ischemia, Alzheimer's disease, and Parkinson's disease are not fully understood. In this article, we focus on current advances that link activation of CysLT1 and CysLT2 to the pathological process during brain ischemia and neurodegeneration and discuss mechanisms by which CysLT1 and CysLT2 mediate inflammatory process and brain injury. Multitarget anti-inflammatory potentials of CysLT1 and CysLT2 antagonism for neuroinflammation and brain injury will also be reviewed.

Ameliorative and protective effects of ginger and its main constituents against natural, chemical and radiation-induced toxicities: A comprehensive review

Fatal unintentional poisoning is widespread upon human exposure to toxic agents such as pesticides, heavy metals, environmental pollutants, bacterial and fungal toxins or even some medications and cosmetic products. In this regards, the application of the natural dietary agents as antidotes has engrossed a substantial attention. One of the ancient known traditional medicines and spices with an arsenal of metabolites of several reported health benefits is ginger. This extended literature review serves to demonstrate the protective effects and mechanisms of ginger and its phytochemicals against natural, chemical and radiation-induced toxicities. Collected data obtained from the in-vivo and in-vitro experimental studies in this overview detail the designation of the protective effects to ginger's antioxidant, anti-inflammatory, and anti-apoptotic properties. Ginger's armoury of phytochemicals exerted its protective function via different mechanisms and cell signalling pathways, including Nrf2/ARE, MAPK, NF-ƙB, Wnt/β-catenin, TGF-β1/Smad3, and ERK/CREB. The outcomes of this review could encourage further clinical trials of ginger applications in radiotherapy and chemotherapy regime for cancer treatments or its implementation to counteract the chemical toxicity induced by industrial pollutants, alcohol, smoking or administered drugs.

Inhibition of the formation of amyloid-like fibrils with spices, especially cloves

During the study of inhibition of amyloid fibril formation, α-chymotrypsin protein was developed in 55% ethanol at pH 7.0. We investigated the inhibitory effect of different spices on amyloid fibril formation using turbidity measurements and Congo red binding assays. We found that all spices except the black pepper and caraway seed prevented fibril formation. The highest inhibition was measured with the clove, which reduced the amount of aggregates by 90%. We studied the inhibitory effect of the cloves at different concentrations on aggregation, it was found that the inhibitory activity of clove is dependent on concentration. We have measured the total phenolic content of the spice extracts too. Based on all these findings we have come to the following conclusion: Our results indicate that spices can contain other compounds too - not only phenolic compounds - which influence the formation of amyloid fibrils, and the effectiveness of various phenolic compounds are different.

A novel therapeutic potential of cysteinyl leukotrienes and their receptors modulation in the neurological complications associated with Alzheimer's disease

Cysteinyl leukotrienes (cysLTs) are member of eicosanoid inflammatory lipid mediators family produced by oxidation of arachidonic acid by action of the enzyme 5-lipoxygenase (5-LOX). 5-LOX is activated by enzyme 5-Lipoxygenase-activating protein (FLAP), which further lead to production of cysLTs i.e. leukotriene C4 (LTC4), leukotriene D4 (LTD4) and leukotriene E4 (LTE4). CysLTs then produce their potent inflammatory actions by activating CysLT1 and CysLT2 receptors. Inhibitors of cysLTs are indicated in asthma, allergic rhinitis and other inflammatory disorders. Earlier studies have associated cysLTs and their receptors in several neurodegenerative disorders diseases like, multiple sclerosis, Parkinson's disease, Huntington's disease, epilepsy and Alzheimer's disease (AD). These inflammatory lipid mediators have previously shown effects on various aggravating factors of AD. However, not much data has been elucidated to test their role against AD clinically. Herein, through this review, we have provided the current and emerging information on the role of cysLTs and their receptors in various neurological complications responsible for the development of AD. In addition, literature evidences for the effect of cysLT inhibitors on distinct aspects of abnormalities in AD has also been reviewed. Promising advancement in understanding on the role of cysLTs on the various neuromodulatory processes and mechanisms may contribute to the development of newer and safer therapy for the treatment of AD in future.

Occurrence, biological activity and metabolism of 6-shogaol

As one of the main bioactive compounds of dried ginger, 6-shogaol has been widely used to alleviate many ailments. It is also a major pungent flavor component, and its precursor prior to dehydration is 6-gingerol, which is reported to be responsible for the pungent flavor and biological activity of fresh ginger. Structurally, gingerols including 6-gingerol have a β-hydroxyl ketone moiety and is liable to dehydrate to generate an α,β-unsaturated ketone under heat and/or acidic conditions. The conjugation of the α,β-unsaturated ketone skeleton in the chemical structure of 6-shogaol explicates its higher potency and efficacy than 6-gingerol in terms of antioxidant, anti-inflammatory, anticancer, antiemetic and other bioactivities. Research on the health benefits of 6-shogaol has been conducted and results have been reported recently; however, scientific data are scattered due to a lack of systematic collection. In addition, action mechanisms of the preventive and/or therapeutic actions of 6-shogaol remain obscurely non-collective. Herein, we review the preparations, biological activity and mechanisms, and metabolism of 6-shogaol as well as the properties of 6-shogaol metabolites.

Pharmacotherapeutic potential of ginger and its compounds in age-related neurological disorders

Age-related neurological disorders (ANDs), including neurodegenerative diseases, are multifactorial disorders with a risk that increases with aging. ANDs are generally characterized by common neuropathological conditions of the central nervous system, such as oxidative stress, neuroinflammation, and protein misfolding. Recently, efforts have been made to overcome ANDs because of the increase in age-dependent prevalence. Ginger, the rhizome of Zingiber officinale Roscoe, is a popular food spice and has a long history of use in traditional medicine for treating various disease symptoms. The structure-activity relationships of ginger phytochemicals show that ginger can be used to treat ANDs by targeting different ligand sites. This review shows that ginger and its constituents, such as 6-gingerol, 6-shogaol, 6-paradol, zingerone, and dehydrozingerone, are effective for ameliorating the neurological symptoms and pathological conditions of ANDs through by modulating cell death or cell survival signaling molecules. From this review, we conclude that the active ingredients in ginger have therapeutic potential in ANDs.

Sortilin-related receptor 1 interacts with amyloid precursor protein and is activated by 6-shogaol, leading to inhibition of the amyloidogenic pathway

Sortilin-related receptor 1 (SORL1) is a neuronal sorting protein that reduces amyloid precursor protein (APP) trafficking to secretases that generate amyloid beta (Aβ). Although 6-shogaol, a constituent of ginger, has been reported to have anti-inflammatory and anti-oxidant effects on neuronal cells, research regarding the activation of SORL1 has not yet been reported. Here, we aimed to investigate whether 6-shogaol contributes to the increases in SORL1 that are related to Alzheimer's disease (AD). To clarify the effect of 6-shogaol as a possible activator of SORL1, we used SORL1 siRNA as a blockade of SORL1 in hippocampal neuronal cells (HT22). We found that SORL1 siRNA treatment naturally inhibited SORL1 and led to increases in β-secretase APP cleaving enzyme (BACE), secreted APP-β (sAPPβ) and Aβ. In contrast, 6-shogaol-mediated activation of SORL1 significantly downregulated BACE, sAPPβ, and Aβ in both in vitro HT22 cells and in vivo APPSw/PS1-dE9 Tg mice. Therefore, SORL1 activation by 6-shogaol provides neuronal cell survival through the inhibition of Aβ production. These results indicate that 6-shogaol should be regarded as an SORL1 activator and a potential preventive agent for the treatment of AD.