Attenuation of oxidative neuronal cell death by coffee phenolic phytochemicals

Polyphenols Targeting MAP Kinase Signaling Pathway in Neurological Diseases: Understanding Molecular Mechanisms and Therapeutic Targets

Polyphenols are a class of secondary metabolic products found in plants that have been extensively studied for how well they regulate biological processes, such as the proliferation of cells, autophagy, and apoptosis. The mitogen-activated protein kinase (MAPK)-mediated signaling cascade is currently identified as a crucial pro-inflammatory pathway that plays a significant role in the development of neuroinflammation. This process has been shown to contribute to the pathogenesis of several neurological conditions, such as Alzheimer's disease (AD), Parkinson's disease (PD), CNS damage, and cerebral ischemia. Getting enough polyphenols through eating habits has resulted in mitigating the effects of oxidative stress (OS) and lowering the susceptibility to associated neurodegenerative disorders, including but not limited to multiple sclerosis (MS), AD, stroke, and PD. Polyphenols possess significant promise in dealing with the root cause of neurological conditions by modulating multiple therapeutic targets simultaneously, thereby attenuating their complicated physiology. Several polyphenolic substances have demonstrated beneficial results in various studies and are presently undergoing clinical investigation to treat neurological diseases (NDs). The objective of this review is to provide a comprehensive summary of the different aspects of the MAPK pathway involved in neurological conditions, along with an appraisal of the progress made in using polyphenols to regulate the MAPK signaling system to facilitate the management of NDs.

Chlorogenic Acid: A Systematic Review on the Biological Functions, Mechanistic Actions, and Therapeutic Potentials

Chlorogenic acid (CGA) is a type of polyphenol compound found in rich concentrations in many plants such as green coffee beans. As an active natural substance, CGA exerts diverse therapeutic effects in response to a variety of pathological challenges, particularly conditions associated with chronic metabolic diseases and age-related disorders. It shows multidimensional functions, including neuroprotection for neurodegenerative disorders and diabetic peripheral neuropathy, anti-inflammation, anti-oxidation, anti-pathogens, mitigation of cardiovascular disorders, skin diseases, diabetes mellitus, liver and kidney injuries, and anti-tumor activities. Mechanistically, its integrative functions act through the modulation of anti-inflammation/oxidation and metabolic homeostasis. It can thwart inflammatory constituents at multiple levels such as curtailing NF-kB pathways to neutralize primitive inflammatory factors, hindering inflammatory propagation, and alleviating inflammation-related tissue injury. It concurrently raises pivotal antioxidants by activating the Nrf2 pathway, thus scavenging excessive cellular free radicals. It elevates AMPK pathways for the maintenance and restoration of metabolic homeostasis of glucose and lipids. Additionally, CGA shows functions of neuromodulation by targeting neuroreceptors and ion channels. In this review, we systematically recapitulate CGA's pharmacological activities, medicinal properties, and mechanistic actions as a potential therapeutic agent. Further studies for defining its specific targeting molecules, improving its bioavailability, and validating its clinical efficacy are required to corroborate the therapeutic effects of CGA.

Molecular mechanism of caloric restriction mimetics-mediated neuroprotection of age-related neurodegenerative diseases: an emerging therapeutic approach

Aging-induced neurodegenerative diseases (NDs) are significantly increasing health problem worldwide. It has been well documented that oxidative stress is one of the potential causes of aging and age-related NDs. There are no drugs for the treatment of NDs, therefore there is an immediate necessity for the development of strategies/treatments either to prevent or cure age-related NDs. Caloric restriction (CR) and intermittent fasting have been considered as effective strategies in increasing the healthspan and lifespan, but it is difficult to adhere to these routines strictly, which has led to the development of calorie restriction mimetics (CRMs). CRMs are natural compounds that provide similar molecular and biochemical effects of CR, and activate autophagy process. CRMs have been reported to regulate redox signaling by enhancing the antioxidant defense systems through activation of the Nrf2 pathway, and inhibiting ROS generation through attenuation of mitochondrial dysfunction. Moreover, CRMs also regulate redox-sensitive signaling pathways such as the PI3K/Akt and MAPK pathways to promote neuronal cell survival. Here, we discuss the neuroprotective effects of various CRMs at molecular and cellular levels during aging of the brain. The CRMs are envisaged to become a cornerstone of the pharmaceutical arsenal against aging and age-related pathologies.

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions

Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement in the pathophysiology of inflammatory diseases, metabolic disorders, and neurological defects. Free radicals increase the concentration of reactive oxygen and nitrogen species in the biological system through different endogenous sources and thus increased the overall oxidative stress. An increase in oxidative stress causes cell death through different signaling mechanisms such as mitochondrial impairment, cell-cycle arrest, DNA damage response, inflammation, negative regulation of protein, and lipid peroxidation. Thus, an appropriate balance between free radicals and antioxidants becomes crucial to maintain physiological function. Since the 1brain requires high oxygen for its functioning, it is highly vulnerable to free radical generation and enhanced ROS in the brain adversely affects axonal regeneration and synaptic plasticity, which results in neuronal cell death. In addition, increased ROS in the brain alters various signaling pathways such as apoptosis, autophagy, inflammation and microglial activation, DNA damage response, and cell-cycle arrest, leading to memory and learning defects. Mounting evidence suggests the potential involvement of micro-RNAs, circular-RNAs, natural and dietary compounds, synthetic inhibitors, and heat-shock proteins as therapeutic agents to combat neurological diseases. Herein, we explain the mechanism of free radical generation and its role in mitochondrial, protein, and lipid peroxidation biology. Further, we discuss the negative role of free radicals in synaptic plasticity and axonal regeneration through the modulation of various signaling molecules and also in the involvement of free radicals in various neurological diseases and their potential therapeutic approaches. The primary cause of free radical generation is drug overdosing, industrial air pollution, toxic heavy metals, ionizing radiation, smoking, alcohol, pesticides, and ultraviolet radiation. Excessive generation of free radicals inside the cell R1Q1 increases reactive oxygen and nitrogen species, which causes oxidative damage. An increase in oxidative damage alters different cellular pathways and processes such as mitochondrial impairment, DNA damage response, cell cycle arrest, and inflammatory response, leading to pathogenesis and progression of neurodegenerative disease other neurological defects.

Coffee Chlorogenic Acids Incorporation for Bioactivity Enhancement of Foods: A Review

The demand of foods with high antioxidant capacity have increased and research on these foods continues to grow. This review is focused on chlorogenic acids (CGAs) from green coffee, which is the most abundant source. The main CGA in coffee is 5-O-caffeoylquinic acid (5-CQA). Coffee extracts are currently the most widely used source to enhance the antioxidant activity of foods. Due to the solubility of CGAs, their extraction is mainly performed with organic solvents. CGAs have been associated with health benefits, such as antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory activity, and others that reduce the risk of cardiovascular diseases, type 2 diabetes, and Alzheimer's disease. However, the biological activities depend on the stability of CGAs, which are sensitive to pH, temperature, and light. The anti-inflammatory activity of 5-CQA is attributed to reducing the proinflammatory activity of cytokines. 5-CQA can negatively affect colon microbiota. An increase in anthocyanins and antioxidant activity was observed when CGAs extracts were added to different food matrices such as dairy products, coffee drinks, chocolate, and bakery products. The fortification of foods with coffee CGAs has the potential to improve the functionality of foods.

Understanding the Complex Interactions between Coffee, Tea Intake and Neurologically Relevant Tissues Proteins in the Development of Anxiety and Depression

OBJECTIVES

Coffee and tea intake might be associated with psychiatry diseases. However, it is unclear whether the effect of coffee/tea on anxiety and depression depending on the different types of proteins.

DESIGN

This was a cross-sectional study.

SETTING

Our datasets were downloaded from online.

PARTICIPANTS

Phenotypic and genotypic data for coffee intake(N=376,196) and tea intake (N=376,078) were derived from UK Biobank. GWAS data of proteins (N=1,537) from neurologically relevant tissues (brain, cerebrospinal fluid (CSF) and plasma) were obtained from a recently published study.

MEASUREMENTS

Multivariate linear analysis was then used to evaluate the potential interaction effect between coffee/tea intake and proteins polygenetic risk score (PRS) on the risks of anxiety and depression controlling for age, sex, Townsend deprivation index (TDI), smoke, drinking and education level.

RESULTS

34 coffee intake-proteins interactions and 15 tea intake-proteins interactions were observed in anxiety individuals, such as coffee intake-c-Jun interaction (β=0.0169, P=4.131×10-3), coffee intake-Fas interaction (β=-0.0190, P=8.132×10-4), tea intake-sL-Selectin interaction (β=0.0112, P=5.412×10-3) and tea intake-IL-1F6 (β=0.0083, P=4.471×10-2). 25 coffee intake-proteins and 14 tea intake-proteins interactions were observed in depression individuals, including coffee intake- IL-1 sRI (β=0.0171, P=4.888×10-3) and coffee intake-NXPH1 interaction (β=0.0156, P=9.819×10-3), tea intake-COLEC12 interaction (β=0.0127, P=3.280×10-3), and tea intake-Layilin interaction (β=0.0117, P=7.926×10-3).

CONCLUSIONS

Our results suggested the important role of multiple proteins in neurologically relevant tissues in the associations between coffee/tea intake and psychiatry diseases, providing entry points to explore the mechanisms underlying anxiety and depression.

Green coffee extract attenuates Parkinson's-related behaviors in animal models

Epidemiological studies have shown an inverse association between coffee consumption and the development of Parkinson's disease (PD). The effects of the oral treatment with green (non-roasted) coffee extracts (CE, 100 or 400 mg/kg) and caffeine (31.2 mg/kg) were evaluated on catalepsy induced by haloperidol in mice, and unilateral 6-OHDA lesion of medial forebrain bundle (MFB) or striatum in rats. Also, the in vitro antioxidant activity and the monoamine levels in the striatum were investigated. CE presented a mild antioxidant activity in vitro and its administration decreased the catalepsy index. CE at the dose of 400 mg/kg induced ipsilateral rotations 14 days after lesion; however, chronic 30-day CE and caffeine treatments did not interfere with the animals' rotation after apomorphine or methamphetamine challenges in animals with MFB lesion, nor on monoamines levels. Furthermore, CE and caffeine were effective in inhibiting the asymmetry between ipsilateral and contralateral rotations induced by methamphetamine and apomorphine in animals with lesion in the striatum but did not avoid the monoamines depletion. These results indicate that CE components indirectly modulate dopaminergic transmission, suggesting a pro-dopaminergic action of CE, and further investigation must be conducted to elucidate the mechanisms of action and the possible neuroprotective role in PD.

Insights into the Pathogenesis of Neurodegenerative Diseases: Focus on Mitochondrial Dysfunction and Oxidative Stress

As the population ages, the incidence of neurodegenerative diseases is increasing. Due to intensive research, important steps in the elucidation of pathogenetic cascades have been made and significantly implicated mitochondrial dysfunction and oxidative stress. However, the available treatment in Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis is mainly symptomatic, providing minor benefits and, at most, slowing down the progression of the disease. Although in preclinical setting, drugs targeting mitochondrial dysfunction and oxidative stress yielded encouraging results, clinical trials failed or had inconclusive results. It is likely that by the time of clinical diagnosis, the pathogenetic cascades are full-blown and significant numbers of neurons have already degenerated, making it impossible for mitochondria-targeted or antioxidant molecules to stop or reverse the process. Until further research will provide more efficient molecules, a healthy lifestyle, with plenty of dietary antioxidants and avoidance of exogenous oxidants may postpone the onset of neurodegeneration, while familial cases may benefit from genetic testing and aggressive therapy started in the preclinical stage.

Chemical Analysis, Toxicity Study, and Free-Radical Scavenging and Iron-Binding Assays Involving Coffee (Coffea arabica) Extracts

We aimed to analyze the chemical compositions in Arabica coffee bean extracts, assess the relevant antioxidant and iron-chelating activities in coffee extracts and instant coffee, and evaluate the toxicity in roasted coffee. Coffee beans were extracted using boiling, drip-filtered and espresso brewing methods. Certain phenolics were investigated including trigonelline, caffeic acid and their derivatives, gallic acid, epicatechin, chlorogenic acid (CGA) and their derivatives, p-coumaroylquinic acid, p-coumaroyl glucoside, the rutin and syringic acid that exist in green and roasted coffee extracts, along with dimethoxycinnamic acid, caffeoylarbutin and cymaroside that may be present in green coffee bean extracts. Different phytochemicals were also detected in all of the coffee extracts. Roasted coffee extracts and instant coffees exhibited free-radical scavenging properties in a dose-dependent manner, for which drip coffee was observed to be the most effective (p < 0.05). All coffee extracts, instant coffee varieties and CGA could effectively bind ferric ion in a concentration-dependent manner resulting in an iron-bound complex. Roasted coffee extracts were neither toxic to normal mononuclear cells nor breast cancer cells. The findings indicate that phenolics, particularly CGA, could effectively contribute to the iron-chelating and free-radical scavenging properties observed in coffee brews. Thus, coffee may possess high pharmacological value and could be utilized as a health beverage.

Using polyphenols as a relevant therapy to diabetes and its complications, a review

Diabetes is currently a worldwide health concern. Hyperglycemia, hypertension, obesity, and oxidative stress are the major risk factors that inevitably lead to all the complications from diabetes. These complications severely impact the quality of life of patients, and they can be managed, reduced, or even reverted by several polyphenols, plant extracts and foods rich in these compounds. The goal of this review is to approach diabetes not as a single condition but rather an interconnected combination of risk factors and complications. This work shows that polyphenols have multi target action and effects and they have been systematically proven to be relevant in the reduction of each risk factor and improvement of associated complication.

The Role of Natural Antioxidants in the Prevention of Dementia-Where Do We Stand and Future Perspectives

Dementia, and especially Alzheimer's disease (AD), puts significant burden on global healthcare expenditure through its increasing prevalence. Research has convincingly demonstrated the implication of oxidative stress in the pathogenesis of dementia as well as of the conditions which increase the risk of developing dementia. However, drugs which target single pathways have so far failed in providing significant neuroprotection. Natural antioxidants, due to their effects in multiple pathways through which oxidative stress leads to neurodegeneration and triggers neuroinflammation, could prove valuable weapons in our fight against dementia. Although efficient in vitro and in animal models of AD, natural antioxidants in human trials have many drawbacks related to the limited bioavailability, unknown optimal dose, or proper timing of the treatment. Nonetheless, trials evaluating several of these natural compounds are ongoing, as are attempts to modify these compounds to achieve improved bioavailability.

Beneficial Effects of Epigallocatechin-3-O-Gallate, Chlorogenic Acid, Resveratrol, and Curcumin on Neurodegenerative Diseases

Many observational and clinical studies have shown that consumption of diets rich in plant polyphenols have beneficial effects on various diseases such as cancer, obesity, diabetes, cardiovascular diseases, and neurodegenerative diseases (NDDs). Animal and cellular studies have indicated that these polyphenolic compounds contribute to such effects. The representative polyphenols are epigallocatechin-3-O-gallate in tea, chlorogenic acids in coffee, resveratrol in wine, and curcumin in curry. The results of human studies have suggested the beneficial effects of consumption of these foods on NDDs including Alzheimer's and Parkinson's diseases, and cellular animal experiments have provided molecular basis to indicate contribution of these representative polyphenols to these effects. This article provides updated information on the effects of these foods and their polyphenols on NDDs with discussions on mechanistic aspects of their actions mainly based on the findings derived from basic experiments.

An optically active isochroman-2H-chromene conjugate potently suppresses neuronal oxidative injuries associated with the PI3K/Akt and MAPK signaling pathways

Increasing evidence suggests that the use of potent neuroprotective agents featured with novel pharmacological mechanism would offer a promising strategy to delay or prevent the progression of neurodegeneration. Here, we provide the first demonstration that the chiral nonracemic isochroman-2H-chromene conjugate JE-133, a novel synthetic 1,3-disubstituted isochroman derivative, possesses superior neuroprotective effect against oxidative injuries. Pretreatment with JE-133 (1-10 μM) concentration-dependently prevented H2O2-induced cell death in SH-SY5Y neuroblastoma cells and rat primary cortical neurons. Pretreatment with JE-133 significantly alleviated H2O2-induced apoptotic changes. These protective effects could not be simply attributed to the direct free radical scavenging as JE-133 had moderate activity in reducing DPPH free radical. Further study revealed that pretreatment with JE-133 (10 μM) significantly decreased the phosphorylation of MAPK pathway proteins, especially ERK and P38, in the neuronal cells. In addition, blocking PI3K/Akt pathway using LY294002 partially counteracted the cell viability-enhancing effect of JE-133. We conclude that JE-133 exerts neuroprotection associated with dual regulative mechanisms and consequently activating cell survival and inhibiting apoptotic changes, which may provide important clues for the development of effective neuroprotective drug lead/candidate.

Neuroprotective Effects of Coffee Bioactive Compounds: A Review

Coffee is one of the most widely consumed beverages worldwide. It is usually identified as a stimulant because of a high content of caffeine. However, caffeine is not the only coffee bioactive component. The coffee beverage is in fact a mixture of a number of bioactive compounds such as polyphenols, especially chlorogenic acids (in green beans) and caffeic acid (in roasted coffee beans), alkaloids (caffeine and trigonelline), and the diterpenes (cafestol and kahweol). Extensive research shows that coffee consumption appears to have beneficial effects on human health. Regular coffee intake may protect from many chronic disorders, including cardiovascular disease, type 2 diabetes, obesity, and some types of cancer. Importantly, coffee consumption seems to be also correlated with a decreased risk of developing some neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and dementia. Regular coffee intake may also reduce the risk of stroke. The mechanism underlying these effects is, however, still poorly understood. This review summarizes the current knowledge on the neuroprotective potential of the main bioactive coffee components, i.e., caffeine, chlorogenic acid, caffeic acid, trigonelline, kahweol, and cafestol. Data from both in vitro and in vivo preclinical experiments, including their potential therapeutic applications, are reviewed and discussed. Epidemiological studies and clinical reports on this matter are also described. Moreover, potential molecular mechanism(s) by which coffee bioactive components may provide neuroprotection are reviewed.

Chlorogenic acid: A comprehensive review of the dietary sources, processing effects, bioavailability, beneficial properties, mechanisms of action, and future directions

Chlorogenic acids (CGAs), a group of hydroxycinnamates, are generally abundant in everyday foods and beverages, most prominently in certain coffee drinks. Among them, the chlorogenic acid (CGA), also termed as 5-O-caffeoylquinic acid (5-CQA), is one of the most abundant, highly functional polyphenolic compounds in the human diet. The evidence of its health benefits obtained from clinical studies, as well as basic research, indicates an inverse correlation between 5-CQA consumption and a lower risk of metabolic syndromes and chronic diseases. This review focuses on the beneficial properties for health and mechanisms of action of 5-CQA, starting with its history, isomers, dietary sources, processing effects, preparation methods, pharmacological safety evaluation, and bioavailability. It also provides the possible molecular mechanistic bases to explain the health beneficial effects of 5-CQA including neuroprotective, cardiovascular protective, gastrointestinal protective, renoprotective, hepatoprotective, glucose and lipid metabolism regulatory, and anticarcinogenic effects. The information summarized here could aid in the basic and clinical research on 5-CQA as a natural dietary additive, potential drug candidate, as well as a natural health promoter.

Protective Effects of Radish Extract Against Neurotoxicity in Mice and PC12 Cells

A variety of natural compounds have been used to reduce the oxidative stress associated with Alzheimer's disease, and many of these defend cells from oxidative stress-induced neuronal toxicity. In this study, the protective effect of radish (Raphanus raphanistrum) extract was investigated in mice and PC12 cells. In vivo behavioral tests were completed to examine the protective effects of the extract on amyloid beta (Aβ)-peptide_1-42-induced learning and memory impairment in a mouse model. The extract increased spontaneous alternation behaviors and step-through latency in mice. We discovered that administration of the extract reduced lipid peroxidation and Aβ aggregation in a biochemical study of mice brain tissues. Treatment with the extract also increased acetylcholine and catalase activity in the brain. Furthermore, the radish extract attenuated H₂O₂-induced oxidative stress in cells. Through sequential fractionation of the radish extract, the active compound was identified as oleamide. These results suggest that the radish extract could have a protective role against oxidative stress-induced neuronal toxicity, possibly owing to the antioxidative activity of oleamide.

Natural Compounds as Beneficial Antioxidant Agents in Neurodegenerative Disorders: A Focus on Alzheimer's Disease

The positive role of nutrition in chronic neurodegenerative diseases (NDs) suggests that dietary interventions represent helpful tools for preventing NDs. In particular, diets enriched with natural compounds have become an increasingly attractive, non-invasive, and inexpensive option to support a healthy brain and to potentially treat NDs. Bioactive compounds found in vegetables or microalgae possess special properties able to counteract oxidative stress, which is involved as a triggering factor in neurodegeneration. Here, we briefly review the relevant experimental data on curcuminoids, silymarin, chlorogenic acid, and compounds derived from the microalga Aphanizomenon flos aquae (AFA) which have been demonstrated to possess encouraging beneficial effects on neurodegeneration, in particular on Alzheimer's disease models.

Protective Effects of the Caffeine Against Neurodegenerative Diseases

Background:

Recent studies and increased interest of the scientific community helped to clarify the neurological health property of caffeine, one of the pharmacologically active substances most consumed in the world.

Methods:

This article is a review search to provide an overview on the current state of understanding neurobiochemical impact of caffeine, focusing on the ability of the drug to effectively counteract several neurodegenerative disorders such as Alzheimer’s, Parkinson’s, Huntington’s diseases, Multiple sclerosis and Amyotrophic lateral sclerosis.

Results:

Data collection shown in this review provide a significant therapeutic and prophylactic potentiality of caffeine which acts on human brain through several pathways because of its antioxidant activity combined with multiple molecular targets. However, the need to adjust the CF dosage to individuals, because some people are more sensitive to drugs than others, may constituted a limit to the CF effectiveness.

Conclusion:

What emerges from the complex of clinical and epidemiological studies is a significant CF potential impact against all neurological disorders. Although, further studies are needed to fully elucidate the several mechanisms of drug action which in part are still elusive.

Chlorogenic acid ameliorates memory loss and hippocampal cell death after transient global ischemia

Chlorogenic acid (CGA) is known to have antioxidant potentials, yet the effect of CGA on brain ischemia has not been sufficiently understood. Brain ischemia such as transient global ischemia disrupts many areas of the brain of rats, including the hippocampus. Male Wistar rats were randomly assigned into five groups, that is, sham-operated (SO), bilateral common carotid occlusion (BCCO), and BCCO+ 15, 30, and 60 mg/kg bw CGA groups (CGA15, CGA30, and CGA60, respectively). Brain ischemia was induced in Wistar rats with BCCO for 20 min followed by intraperitoneal injection of CGA. The rats were examined for the spatial memory in a Morris water maze test on the 3rd day and were euthanized on the 10th day after BCCO. The total number of pyramidal cells was estimated, and the mRNA expressions of Bcl2, Bax, caspase-3, SOD2, SOD1, GPx, ET-1, eNOS, CD31, and VEGF-A were measured. The BCCO group spent less time and distance in the target quadrant than any other group in the spatial memory retention test. The CA1 pyramidal cell numbers in the BCCO and CGA15 groups were lower than in the CGA30 and CGA60 groups. The mRNA expressions of Bcl2, SOD2, and CD31 in the BCCO group were lower than in the CGA15, CGA30, and CGA60 groups. The ET-1 expression was higher in the BCCO and CGA15 groups than in the SO, CGA30, and CGA60 groups. CGA improves the spatial memory and prevents the CA1 pyramidal cell death after BCCO by increasing Bcl2, SOD2, and CD31 expressions and decreasing ET-1 expression.

Chlorogenic acid protects against aluminium-induced cytotoxicity through chelation and antioxidant actions in primary hippocampal neuronal cells

Chlorogenic acid (CGA), a major polyphenolic component of many plants, displays antioxidant and neuroprotective properties in neurodegenerative diseases. To investigate whether CGA may influence aluminium (Al) induced cytotoxicity, aluminium chloride (50 μM Al) was administered in primary hippocampal neuronal cells presupplemented with CGA (10, 50 and 100 μM). Our study shows that the exposure to Al caused cell death, Al³⁺ accumulation, reactive oxygen species generation and mitochondrial damage in cells. The administration of CGA (50 μM) increased cell viability by 37.5%, decreased the levels of Al³⁺ by 26.0%, together with significantly weakening the oxidative damage compared with Al treatment alone. CGA protected neurons against Al-induced oxidative stress by increasing the expression of nuclear factor-E2-related factor 2 and its target phase 2 enzymes. The administration of CGA remarkably promoted the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, creatine kinase and acetylcholinesterase and attenuated the rate of ATP hydrolysis. Our finding shows that CGA has neuroprotective effects against Al-induced cytotoxicity by chelation and antioxidant activation.

Quercetin suppresses NLRP3 inflammasome activation in epithelial cells triggered by Escherichia coli O157:H7

Inflammatory responses elicited by LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is induced by a wide variety of stress signals including infectious agents and cellular disorders. E. coli O157:H7 causes serious gastrointestinal diseases that results in severe inflammation and oxidative stress, causing host cell damage. In this study, we found that E. coli O157:H7 infection induced NLRP3 assembly, caspase-1 activation and interleukin (IL)-1β and IL-18 release in Caco-2 cells. Infection also resulted in mitochondrial dysfunction with disrupted mitochondrial potential and mitochondrial complex-I activity, as well as the cytosolic release of cytochrome c and altered mitochondrial respiratory chain. The damage of mitochondria led to increased production of reactive oxygen species (ROS) and cytosolic release of mitochondrial DNA. Moreover, ROS was required for E. coli O157:H7 induced NLRP3 assembly as inhibiting mitochondrial ROS release by ROS scavengers Mito-TEMPO and N-acetylcysteine abrogated NLRP3 inflammasome activation in Caco-2 cells in response to E. coli O157:H7. Quercetin, one of the most important flavonoids in plant origin foods, had a protective role in inhibiting NLRP3 activation upon E. coli O157:H7 infection by protecting mitochondrial integrity and inhibiting mitochondrial ROS release. In addition, E. coli O157:H7 infection inhibited the host autophagy while quercetin treatment augmented autophagy activation, which further blocked ROS generation and IL-1β and IL-18 release. In summary, E. coli O157:H7 infection induced mitochondrial ROS release and NLRP3 assembly in host cells, while quercetin exerted a preventive role in host cells upon E. coli O157:H7 infection partially due to prevention of ROS production and activation of autophagy.

The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: a comprehensive review of the literature

Chlorogenic acid (CGA), an important biologically active dietary polyphenol, is produced by certain plant species and is a major component of coffee. Reduction in the risk of a variety of diseases following CGA consumption has been mentioned in recent basic and clinical research studies. This systematic review discusses in vivo animal and human studies of the physiological and biochemical effects of chlorogenic acids (CGAs) on biomarkers of chronic disease. We searched PubMed, Embase, Amed and Scopus using the following search terms: ("chlorogenic acid" OR "green coffee bean extract") AND (human OR animal) (last performed on April 1st, 2015) for relevant literature on the in vivo effects of CGAs in animal and human models, including clinical trials on cardiovascular, metabolic, cancerogenic, neurological and other functions. After exclusion of editorials and letters, uncontrolled observations, duplicate and not relevant publications the remaining 94 studies have been reviewed. The biological properties of CGA in addition to its antioxidant and anti-inflammatory effects have recently been reported. It is postulated that CGA is able to exert pivotal roles on glucose and lipid metabolism regulation and on the related disorders, e.g. diabetes, cardiovascular disease (CVD), obesity, cancer, and hepatic steatosis. The wide range of potential health benefits of CGA, including its anti-diabetic, anti-carcinogenic, anti-inflammatory and anti-obesity impacts, may provide a non-pharmacological and non-invasive approach for treatment or prevention of some chronic diseases. In this study, the effects of CGAs on different aspects of health by reviewing the related literatures have been discussed.

Chlorogenic Acid and Mental Diseases: From Chemistry to Medicine

BACKGROUND

At present, much attention has been focused on the beneficial effects of natural products on the human health due to their high efficacy and low adverse effects. Among them, polyphenolic compounds are known as one of the most important and common classes of natural products, which possess multiple range of health-promotion effects including anti-inflammatory and antioxidant activities. A plethora of scientific evidence has shown that polyphenolic compounds possess beneficial effects on the central nervous system.

METHODS

Data were collected from Web of Science (ISI Web of Knowledge), Medline, Pubmed, Scopus, Embase, and BIOSIS Previews (from 1950 to 2015), through searching of these keywords: "chlorogenic acid and mental diseases" and "chlorogenic acid and neuroprotection".

RESULTS

Chlorogenic acid is known as one of the most common polyphenolic compounds, and is found in different types of fruits and vegetables, spices, wine, olive oil, as well as coffee. The potential neuroprotective effects of chlorogenic acid have been highlighted in several in vitro and in vivo studies. This review critically analyses the available scientific evidence regarding the neuroprotective effects of chlorogenic acid, and its neuropharmacological mechanisms of action. In addition, we also discuss its biosynthesis, sources, bioavailability and metabolism, to provide a broad perspective of the therapeutic implications of this compound in brain health and disease.

CONCLUSION

The present review showed that chlorogenic acid possesses neuroprotective effects under the both in vitro and in vivo models.

Essential Roles of Natural Products and Gaseous Mediators on Neuronal Cell Death or Survival

Although precise cellular and molecular mechanisms underlying neurodegeneration still remain enigmatic, key factors associated with degenerative disorders, such as glutamate toxicity and oxidative stress, have been recently identified. Accordingly, there has been growing interest in examining the effects of exogenous and endogenous molecules on neuroprotection and neurodegeneration. In this paper, we review recent studies on neuroprotective and/or neurodegenerative effects of natural products, such as caffeic acid and chlorogenic acid, and gaseous mediators, including hydrogen sulfide and nitric oxide. Furthermore, possible molecular mechanisms of these molecules in relation to glutamate signals are discussed. Insight into the pathophysiological role of these molecules will make progress in our understanding of molecular mechanisms underlying neurodegenerative diseases, and is expected to lead to potential therapeutic approaches.

The Extract of Aster Koraiensis Prevents Retinal Pericyte Apoptosis in Diabetic Rats and Its Active Compound, Chlorogenic Acid Inhibits AGE Formation and AGE/RAGE Interaction

Retinal capillary cell loss is a hallmark of early diabetic retinal changes. Advanced glycation end products (AGEs) are believed to contribute to retinal microvascular cell loss in diabetic retinopathy. In this study, the protective effects of Aster koraiensis extract (AKE) against damage to retinal vascular cells were investigated in streptozotocin (STZ)-induced diabetic rats. To examine this issue further, AGE accumulation, nuclear factor-kappaB (NF-κB) and inducible nitric oxide synthase (iNOS) were investigated using retinal trypsin digests from streptozotocin-induced diabetic rats. In the diabetic rats, TUNEL (Terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling)-positive retinal microvascular cells were markedly increased. Immunohistochemical studies revealed that AGEs were accumulated within the retinal microvascular cells, and this accumulation paralleled the activation of NF-κB and the expression of iNOS in the diabetic rats. However, AKE prevented retinal microvascular cell apoptosis through the inhibition of AGE accumulation and NF-κB activation. Moreover, to determine the active compounds of AKE, two major compounds, chlorogenic acid and 3,5-di-O-caffeoylquinic acid, were tested in an in vitro assay. Among these compounds, chlorogenic acid significantly reduced AGE formation as well as AGE/RAGE (receptor for AGEs) binding activity. These results suggest that AKE, particularly chlorogenic acid, is useful in inhibiting AGE accumulation in retinal vessels and exerts a preventive effect against the injuries of diabetic retinal vascular cells.

Cognitive and neuroprotective effects of chlorogenic acid

OBJECTIVES

The aim of this review was to provide an overview of studies conducted to determine the effects of chlorogenic acid (CGA) on cognition and neurological health.

METHODS

A literature search was conducted using PubMed and various search terms including chlorogenic acid, CGA, memory, neuroscience, cognition, nutrition, antioxidant, pharmacokinetics, neuroprotection, and neurodegeneration.

RESULTS

Many studies have linked CGA consumption to a wide range of health benefits, including neuroprotection, cardioprotection, weight loss, chemopreventive properties, anti-inflammatory activity, decreased blood pressure, decreased diet-induced insulin resistance, decreased blood pressure, anxiolytic effects, and antihyperalgesic effects. Pre-clinical and clinical studies both provide evidence that CGA supplementation could protect against neurological degeneration and the resulting diseases associated with oxidative stress in the brain; however, no formal, well-controlled studies have been performed to date.

DISCUSSION

Recent research suggests that dietary consumption of CGA could produce a wide range of health benefits and physiological effects. There is also mounting evidence that the consumption of polyphenols, including CGA, in the diet could reduce the risk of developing neurodegenerative conditions. Further studies should be conducted with a focus on the effects of CGA on cognition and the nervous system and employing well-designed clinical studies.

YGS40, an active fraction of Yi-Gan San, reduces hydrogen peroxide-induced apoptosis in PC12 cells

In our previous study, we have elucidated the chemical profile of YGS40, a fraction of Yi-Gan San (YGS), used for the treatment of Alzheimer's disease (AD). Oxidative stress-induced apoptosis is implicated in neurodegenerative disorders such as AD. The aim of the present study was to explore the protective effects of YGS40 against hydrogen peroxide (H2O2)-induced apoptosis in PC12 cells and the underlying mechanisms. PC12 cells were exposed to 100 μmol·L(-1) of H2O2 for 12 h with or without YGS40 pretreatment. Cytotoxicity was determined by MTT (3, (4, 5-dimethylthiazole-2-yl) 2, 5-diphenyl-tetrazolium bromide) and lactate dehydrogenase (LDH) release assays; apoptosis was detected by Annexin V/propidium iodide coupled staining and by determining caspase-3 activity and Bax and Bcl-2 protein levels. Mitochondrial membrane potential (MMP) was assessed by the retention of rhodamine123; and the activities of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured using commercially available enzymatic kits. Pretreatment with YGS40 significantly prevented H2O2-induced cytotoxicity and protected the cells against H2O2-triggered apoptosis characterized by externalization of membrane phosphatidylserine and caspase-3 activation and the increased ratio of Bax/Bcl-2 in PC12 cells. Further studies showed that YGS40 suppressed H2O2-induced MMP loss, increased SOD activity, and decreased MDA level. These findings suggest that YGS40 may be beneficial for the prevention and treatment of oxidative stress-mediated disorders.

Polysaccharides from Angelica sinensis alleviate neuronal cell injury caused by oxidative stress

Angelica sinensis has antioxidative and neuroprotective effects. In the present study, we aimed to determine the neuroprotective effect of polysaccharides isolated from Angelica sinensis. In a preliminary experiment, Angelica sinensis polysaccharides not only protected PC12 neuronal cells from H₂O₂-induced cytotoxicity, but also reduced apoptosis and intracellular reactive oxygen species levels, and increased the mitochondrial membrane potential induced by H₂O₂ treatment. In a rat model of local cerebral ischemia, we further demonstrated that Angelica sinensis polysaccharides enhanced the antioxidant activity in cerebral cortical neurons, increased the number of microvessels, and improved blood flow after ischemia. Our findings highlight the protective role of polysaccharides isolated from Angelica sinensis against nerve cell injury and impairment caused by oxidative stress.

Potential impact of silymarin in combination with chlorogenic acid and/or melatonin in combating cardiomyopathy induced by carbon tetrachloride

The aim of this study was to investigate the effective role of silymarin either alone or in combination with chlorogenic acid and/or melatonin against the toxic impact of carbon tetrachloride (CCl4) induced cardiac infarction. CCl4 (l.2 ml/kg body weight) was administered as a single dose intraperitoneally. The results revealed that the administration of silymarin alone or in combination with chlorogenic acid (CGA) and/or melatonin for 21 consecutive days, 24 h after CCl4 injection to rats, markedly ameliorated the increases in serum markers of cardiac infarction, including troponin T and creatine kinase-MB (CK-MB), as well as increases in the pro-inflammatory biomarkers, including interleukin-6 (IL-6), interferon-γ (IFN-γ) in serum and tumor necrosis factor-α (TNF-α) and C-reactive protein in cardiac tissue compared to CCl4 intoxicated rats. The used agents also successfully modulated the alteration in vascular endothelial growth factor (VEGF) in serum and the oxidative DNA damage and the increase in the apoptosis marker caspase 3 in cardiac tissue in response to CCl4 toxicity. The present biochemical results are supported by histo-pathological examination. The current results proved that treatment with silymarin in combination with CGA and melatonin was the most effective one in ameliorating the toxicity of CCl4 induced cardiac damage and this may support the use of this combination as an effective drug to treat cardiac damage induced by toxic agents.

Neuroprotective effects of bikaverin on H2O2-induced oxidative stress mediated neuronal damage in SH-SY5Y cell line

The generation of free radicals and oxidative stress has been linked to several neurodegenerative diseases including Parkinson's disease, Alzheimer's disease, Huntington's disease, and Amyotrophic lateral sclerosis. The use of free radical scavenging molecules for the reduction of intracellular reactive oxygen species is one of the strategies used in the clinical management of neurodegeneration. Fungal secondary metabolism is a rich source of novel molecules with potential bioactivity. In the current study, bikaverin was extracted from Fusarium oxysporum f. sp. lycopersici and its structural characterization was carried out. Further, we explored the protective effects of bikaverin on oxidative stress and its anti-apoptotic mechanism to attenuate H2O2-induced neurotoxicity using human neuroblastoma SH-SY5Y cells. Our results elucidate that pretreatment of neurons with bikaverin attenuates the mitochondrial and plasma membrane damage induced by 100 µM H2O2 to 82 and 26% as evidenced by MTT and LDH assays. H2O2 induced depletion of antioxidant enzyme status was also replenished by bikaverin which was confirmed by Realtime Quantitative PCR analysis of SOD and CAT genes. Bikaverin pretreatment efficiently potentiated the H2O2-induced neuronal markers, such as BDNF, TH, and AADC expression, which orchestrate the neuronal damage of the cell. The H2O2-induced damage to cells, nuclear, and mitochondrial integrity was also restored by bikaverin. Bikaverin could be developed as a preventive agent against neurodegeneration and as an alternative to some of the toxic synthetic antioxidants.

Icariin attenuates glucocorticoid insensitivity mediated by repeated psychosocial stress on an ovalbumin-induced murine model of asthma

Evidence shows that psychosocial stress exacerbates asthma, but there is little intervention to alleviate negative effects of psychosocial stress on asthma. We investigated the role of icariin in anti-inflammation and anti-anxiety potential in a murine model combined psychosocial stress with allergic exposure. The results indicated that icariin administered remarkable increased activity in the center of the open field, reversed airway hyperresponsivenesss, reduced inflammatory cytokine infiltration to the lung and whole body and also in part recovered glucocorticoid responsiveness. Furthermore, our data also showed that icariin significantly inhibited increases of corticosterone and markedly increased glucocorticoid receptor mRNA and protein expression in the lungs of mice exposed to both stress and allergen. Collectively, we speculate that inducing glucocorticoid receptor modulation might be the potential mechanisms of icariin to facilitate corticosteroid responsiveness of cytokine production.

Green coffee as a novel agent for Alzheimer’s disease prevention by attenuating diabetes

Diabetes type 2, caused mainly by insulin resistance, is growing in incidence worldwide. In addition to being a major public health concern, type 2 diabetes is also a risk factor for dementia, including Alzheimer’s disease type dementia. Coffee consumption is reported to have protective effects in both diabetes and Alzheimer’s disease. We review here the reported beneficial effects of coffee in both disease conditions and the previously identified active ingredients of coffee. Furthermore, we revisit our recent findings of improved glucose utilization in the periphery and in the brain in a mouse model of high-fat diet induced type 2 diabetes after treatment with a decaffeinated green coffee preparation. Overall, consumption of coffee appears to improve diabetes and reduce the risk of dementia, although future studies are required to further identify the active components and the type of coffee that is most effective in addressing these conditions.

Coffee, but not caffeine, has positive effects on cognition and psychomotor behavior in aging

The complex mixture of phytochemicals in fruits and vegetables provides protective health benefits, mainly through additive and/or synergistic effects. The presence of several bioactive compounds, such as polyphenols and caffeine, implicates coffee as a potential nutritional therapeutic in aging. Moderate (three to five cups a day) coffee consumption in humans is associated with a significant decrease in the risk of developing certain chronic diseases. However, the ability of coffee supplementation to improve cognitive function in aged individuals and the effect of the individual components in coffee, such as caffeine, have not been fully evaluated. We fed aged rats (19 months) one of five coffee-supplemented diets (0, 0.165, 0.275, 0.55, and 0.825% of the diet) for 8 weeks prior to motor and cognitive behavior assessment. Aged rats supplemented with a 0.55% coffee diet, equivalent to ten cups of coffee, performed better in psychomotor testing (rotarod) and in a working memory task (Morris water maze) compared to aged rats fed a control diet. A diet with 0.55% coffee appeared to be optimal. The 0.165% coffee-supplemented group (three cups) showed some improvement in reference memory performance in the Morris water maze. In a subsequent study, the effects of caffeine alone did not account for the performance improvements, showing that the neuroprotective benefits of coffee are not due to caffeine alone, but rather to other bioactive compounds in coffee. Therefore, coffee, in achievable amounts, may reduce both motor and cognitive deficits in aging.

Oxidative stress and cardiovascular health: therapeutic potential of polyphenols

Reactive oxygen species (ROS) are important in normal cellular function and physiology. However, oxidative stress resulting from an accumulation of ROS has a detrimental impact on cellular function, and ROS has been implicated in the pathogenesis of a number of diseases, including cardiovascular diseases. This review provides a summary of the impact of ROS on cardiovascular health and diseases, highlighting the therapeutic use of antioxidants. In addition, this review summarizes the health benefits of polyphenols, and the recent progress on understanding the cellular and physiological actions by which polyphenols may impart their beneficial properties on cardiovascular health.

Decaffeinated coffee prevents scopolamine-induced memory impairment in rats

INTRODUCTION

Several human studies have reported that coffee consumption improves cognitive performance. In the present study, we investigated whether instant decaffeinated coffee also ameliorates cognitive performance and attenuates the detrimental effects of scopolamine on memory.

METHODS

Memory performance was evaluated in Morris water maze test and passive avoidance test. Instant decaffeinated coffee (p.o.) at 120 or 240 mg/kg in Sprague-Dawley rats, which is equivalent to approximately three or six cups of coffee, respectively, in a 60 kg human, was administered for two weeks.

RESULTS

Oral gavage administration of instant decaffeinated coffee inhibited scopolamine-induced memory impairment, which was measured by Morris water maze test and passive avoidance test. Instant decaffeinated coffee suppressed scopolamine-mediated elevation of tumor necrosis factor-α (TNF-α) and stimulation of nuclear factor-κB (NF-κB) pathway (i.e., phosphorylation of IκBα and p65) in the rat hippocampus.

DISCUSSION

These findings suggest that caffeine-free decaffeinated coffee may prevent memory impairment in human through the inhibition of NF-κB activation and subsequent TNF-α production.

Chlorogenic acid attenuates high mobility group box 1 (HMGB1) and enhances host defense mechanisms in murine sepsis

Sepsis is a complex, multifactorial, rapidly progressive disease characterized by an overwhelming activation of the immune system and the countervailing antiinflammatory response. In the current study in murine peritoneal macrophages, chlorogenic acid suppressed endotoxin-induced high mobility group box 1 (HMGB1) release in a concentration-dependent manner. Administration of chlorogenic acid also attenuated systemic HMGB1 accumulation in vivo and prevented mortality induced by endotoxemia and polymicrobial sepsis. The mechanisms of action of chlorogenic acid included attenuation of the increase in toll-like receptor (TLR)-4 expression and suppression of sepsis-induced signaling pathways, such as c-Jun NH₂-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB, which are critical for cytokine release. The protection conferred by chlorogenic acid was achieved through modulation of cytokine and chemokine release, suppression of immune cell apoptosis and augmentation of bacterial elimination. Chlorogenic acid warrants further evaluation as a potential therapeutic agent for the treatment of sepsis and other potentially fatal systemic inflammatory disorders.

Selenium increases chlorogenic acid, chlorophyll and carotenoids of Lycium chinense leaves

BACKGROUND

Leaves of Lycium chinense L. are widely used in traditional Chinese medicine and as functional food in China and south-east Asia. Polyphenols are important active compounds in leaves of L. chinense L, but their compositions are still not very clear. Selenium has been reported to increase some components of plants. In this study, the composition of polyphenols of L. chinense leaves were analysed, and the effects of selenium on the polyphenols and other components were studied.

RESULTS

The main polyphenols were identified as rutin, chlorogenic acid, quercetin, kaempferol and apigenin-7-O-(6'-O-acetyl) glucose-rhamnose. Chlorogenic acid showed the highest average content of 78.36 g kg⁻¹. Rutin, quercetin and kaempferol were determined at low contents from 3.85 g kg⁻¹ to 7.08 g kg⁻¹. Correlation coefficients between selenium and chlorogenic acid, chlorophyll a, chlorophyll b and carotenoids were: R² = 0.963 (P = 0.002), 0.943 (P = 0.005), 0.957 (P = 0.003) and 0.943 (P = 0.005), respectively. Selenium (0.01-0.05 g kg⁻¹) significantly increased chlorogenic acid, chlorophyll and carotenoids by 200-400% and reduced rutin by 400-900%.

CONCLUSION

L. chinense can be an alternative source of chlorogenic acid. Selenium significantly increased chlorogenic acid, chlorophyll a, chlorophyll b and carotenoids, hence increasing the medicinal value of L. chinense leaves. Rutin, quercetin, kaempferol and apigenin-7-O-(6'-O-acetyl) glucose-rhamnose proved to be not significantly influenced by selenium.