Caffeic acid phenethyl ester prevents cerebellar granule neurons (CGNs) against glutamate-induced neurotoxicity

Caffeic acid phenethyl ester ameliorates imidacloprid-induced acute toxicity in the rat cerebral cortex

This study aimed to investigate the role of caffeic acid phenethyl ester (CAPE), a compound found in propolis, on imidacloprid (IMI), a nicotinic acetylcholine receptor agonist that causes cerebral toxicity. 60 adult rats were randomly divided into five groups: control, IMI (100 mg/kg), and IMI+CAPE (1, 5, 10 mg/kg). Cerebral cortex tissue was examined histopathologically, biochemically, spectrophotometrically and immunohistochemically. The results showed that IMI caused toxicity in the cerebral cortex. However, CAPE (5 and 10 mg/kg) attenuated the deteriorated histopathological score and normalized the apoptotic markers (Bax and Caspase-3). Additionally, CAPE dose-dependently normalized the levels of TNF-α, dopamin, GFAP and NGF, and at the highest dose (10 mg/kg) also normalized the balance of oxidative parameters (MDA, SOD, CAT, and GSH). In conclusion, the antioxidant, anti-inflammatory, and anti-apoptotic effects of CAPE may be a promising treatment for acute IMI-induced cerebral cortex toxicity.

CAPE and its synthetic derivative VP961 restore BACH1/NRF2 axis in Down Syndrome

The cells possess several mechanisms to counteract the over-production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), including enzymes such as superoxide dismutase, catalase and glutathione peroxidase. Moreover, an important sensor involved in the anti-oxidant response is KEAP1-NRF2-ARE signaling complex. Under oxidative stress (OS), the transcription factor NRF2 can dissociate from the KEAP1-complex in the cytosol and translocate into the nucleus to promote the transcriptional activation of anti-oxidant genes, such as heme oxygenase 1 and NADPH quinone oxidoreductase. Within this context, the activation of NRF2 response is further regulated by BACH1, a transcription repressor, that compete with the KEAP1-NRF2-ARE complex. In this work, we focused on the role of BACH1/NRF2 ratio in the regulation of the anti-oxidant response, proposing their antithetical relation as a valuable target for a therapeutic strategy to test drugs able to exert neuroprotective effects, notably in aging and neurodegenerative diseases. Among these, Down syndrome (DS) is a complex genetic disorder characterized by BACH1 gene triplication that likely results in the impairment of NRF2 causing increased OS. Our results revealed that BACH1 overexpression alters the BACH1/NRF2 ratio in the nucleus and disturbs the induction of antioxidant response genes ultimately resulting in the accumulation of oxidative damage both in Ts2Cje mice (a mouse model of DS) and human DS lymphoblastoid cell lines (LCLs). Based on this evidence, we tested Caffeic Acid Phenethyl Ester (CAPE) and the synthetic analogue VP961, which have been proven to modulate NRF2 activity. We showed that CAPE and VP961 administration to DS LCLs was able to promote NRF2 nuclear translocation, which resulted in the amelioration of antioxidant response. Overall, our study supports the hypothesis that BACH1 triplication in DS subjects is implicated in the alteration of redox homeostasis and therapeutic strategies to overcome this effect are under investigation in our laboratory.

A Novel Synthetic Precursor of Styryl Sulfone Neuroprotective Agents Inhibits Neuroinflammatory Responses and Oxidative Stress Damage through the P38 Signaling Pathway in the Cell and Animal Model of Parkinson's Disease

A novel class of styryl sulfones were designed and synthesized as CAPE derivatives by our work team, which showed a multi-target neuroprotective effect, including antioxidative and anti-neuroinflammatory properties. However, the underlying mechanisms remain unclear. In the present study, the anti-Parkinson’s disease (PD) activity of 10 novel styryl sulfone compounds was screened by the cell viability test and the NO inhibition test in vitro. It was found that 4d exhibited the highest activity against PD among them. In a MPTP-induced mouse model of PD, the biological activity of 4d was validated through suppressing dopamine neurotoxicity, microglial activation, and astrocytes activation. With compound 4d, we conducted the mechanistic studies about anti-inflammatory responses through inhibition of p38 phosphorylation to protect dopaminergic neurons, and antioxidant effects through promoting nuclear factor erythroid 2-related factor 2 (Nrf2). The results revealed that 4d could significantly inhibit 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/1-methyl-4-phenylpyridinium (MPTP/MPP⁺)-induced p38 mitogen-activated protein kinase (MAPK) activation in both in vitro and in vivo PD models, thus inhibiting the NF-κB-mediated neuroinflammation-related apoptosis pathway. Simultaneously, it could promote Nrf2 nuclear transfer, and upregulate the expression of antioxidant phase II detoxification enzymes HO-1 and GCLC, and then reduce oxidative damage.

Neuroprotection against 1-Methyl-4-phenylpyridinium-induced cytotoxicity by naturally occurring polydatin through activation of transcription factor MEF2D

Polydatin is the major active ingredient of Polygonum cuspidatum Sieb. Et Zucc. A recent study indicated that polydatin could protect against substantia nigra dopaminergic degeneration in rodent models associated with Parkinson's disease. However, mechanisms that underlie the neuroprotection of polydatin have not been fully elucidated. In the current study, the neuroprotective effects and detailed mechanisms of action of polydatin were investigated in Parkinson's disease-related cellular models. Polydatin dose- and time-dependently prevented neurotoxicity caused by 1-methyl-4-phenylpyridinium ion (MPP+) in primary cerebellar granule neurons. Moreover, we found that polydatin enhanced the activity of the transcription factor myocyte enhancer factor 2D (MEF2D) at both basal and pathological conditions using luciferase reporter gene assay. Additionally, western blot analysis revealed that polydatin could downregulate glycogen synthase kinase 3β (GSK3β), which is a negative regulator of MEF2D. Molecular docking simulations finally suggested an interaction between polydatin and a hydrophobic pocket within GSK3β. All these results suggest that polydatin prevents MPP+-induced neurotoxicity via enhancing MEF2D through the inhibition of GSK3β and that treatment with polydatin is worthy of further anti-Parkinson's disease study in future.

Recent progresses in the pharmacological activities of caffeic acid phenethyl ester

The past decades have seen a growing interest in natural products. Caffeic acid phenethyl ester (CAPE), a flavonoid isolated from honeybee propolis, has shown multiple pharmacological potentials, including anti-cancer, anti-inflammatory, antioxidant, antibacterial, antifungal, and protective effects on nervous systems and multiple organs, since it was found as a potent nuclear factor κB (NF-κB) inhibitor. This review summarizes the advances in these beneficial effects of CAPE, as well as the underlying mechanisms, and proposes that CAPE offers an opportunity for developing therapeutics in multiple diseases. However, clinical trials on CAPE are necessary and encouraged to obtain certain clinically relevant conclusions.

The effects of caffeic acid phenethyl ester on retina in a diabetic rat model

PURPOSE

We aimed to investigate the effect of caffeic acid phenethyl ester (CAPE) on retinal apoptosis and oxidative stress parameters in streptozotocin (STZ) induced diabetic rat model.

METHODS

This study included 3 groups; control, STZ, and STZ + CAPE. The rats in STZ, and STZ + CAPE groups were injected with STZ (35 mg/kg, i.p.) for induction of diabetes. In the STZ + CAPE group, 10 µmol/kg of CAPE were intraperitoneally injected for 4 weeks. Control and STZ groups were given only intraperitoneal vehicle (saline). Rats were anaesthetized and sacrificed on the 4th week of the experiment. Total anti-oxidant status (TAS), and total oxidant status (TOS) were measured on the dissected retinal tissues. Oxidative stress index (OSI) was also calculated. Fellow eyes were used for histopathologic evaluation with caspase-3 and matrix metalloproteinase-2 (MMP-2) and MMP-9 evaluation.

RESULTS

TAS levels were similar between groups (p = 0.71). However, CAPE treatment prevented the elevation of the TOS in the STZ + CAPE group compared to the STZ group (30.93 ± 9.97 vs 61.53 ± 24.7 nmol H₂O₂ Eq/mg protein, p = 0.007). OSI was also significantly lower in the STZ + CAPE group than that of the STZ group (20.01 ± 5.87 vs. 37.90 ± 14.32, respectively, p = 0.007). Retinal caspase-3 staining, MMP-2 and MMP-9 scores were not different between groups (p > 0.05 for all).

CONCLUSION

The present study demonstrated that CAPE treatment may decrease the oxidative stress in the retina in STZ induced diabetic rat model. However, apoptosis was not observed in the retina. The retinal apoptosis cannot be shown probably due to a shorter period of diabetes.

The Pluripotent Activities of Caffeic Acid Phenethyl Ester

Caffeic acid phenethyl ester (CAPE) is a strong antioxidant extracted from honey bee-hive propolis. The mentioned compound, a well-known NF-κB inhibitor, has been used in traditional medicine as a potent anti-inflammatory agent. CAPE has a broad spectrum of biological properties including anti-viral, anti-bacterial, anti-cancer, immunomodulatory, and wound-healing activities. This review characterizes published data about CAPE biological properties and potential therapeutic applications, that can be used in various diseases.

CAPE and Neuroprotection: A Review

Propolis, a product of the honey bee, has been used in traditional medicine for many years. A hydrophobic bioactive polyphenolic ester, caffeic acid phenethyl ester (CAPE), is one of the most extensively investigated active components of propolis. Several studies have indicated that CAPE has a broad spectrum of pharmacological activities as anti-oxidant, anti-inflammatory, anti-viral, anti-fungal, anti-proliferative, and anti-neoplastic properties. This review largely describes CAPE neuroprotective effects in many different conditions and summarizes its molecular mechanisms of action. CAPE was found to have a neuroprotective effect on different neurodegenerative disorders. At the basis of these effects, CAPE has the ability to protect neurons from several underlying causes of various human neurologic diseases, such as oxidative stress, apoptosis dysregulation, and brain inflammation. CAPE can also protect the nervous system from some diseases which negatively affect it, such as diabetes, septic shock, and hepatic encephalopathy, while numerous studies have demonstrated the neuroprotective effects of CAPE against adverse reactions induced by different neurotoxic substances. The potential role of CAPE in protecting the central nervous system (CNS) from secondary injury following various CNS ischemic conditions and CAPE anti-cancer activity in CNS is also reviewed. The structure–activity relationship of CAPE synthetic derivatives is discussed as well.

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.

Propolis: A useful agent on psychiatric and neurological disorders? A focus on CAPE and pinocembrin components

Propolis consists of a honeybee product, with a complex mix of substances that have been widely used in traditional medicine. Among several compounds present in propolis, caffeic acid phenethyl ester (CAPE), and pinocembrin emerge as two principal bioactive compounds, with benefits in a variety of body systems. In addition to its well-explored pharmacological properties, neuropharmacological activities have been poorly discussed. In an unprecedented way, the present review addresses the current finding on the promising therapeutic purposes of propolis, focusing on CAPE and pinocembrin, highlighting its use on neurological disturbance, as cerebral ischemia, neuroinflammation, convulsion, and cognitive impairment, as well as psychiatric disorders, such as anxiety and depression. In addition, we provide a critical analysis, discussion, and systematization of the molecular mechanisms which underlie these central nervous system effects. We hypothesize that the pleiotropic action of CAPE and pinocembrin, per se or associated with other substances present in propolis may result in the therapeutic activities reported. Inhibition of the pro-inflammatory cascade, antioxidant activity, and positive neurotrophic modulatory effects consist of the main molecular targets attributed to CAPE and pinocembrin in health benefits.

Identification of Caffeic Acid Phenethyl Ester (CAPE) as a Potent Neurodifferentiating Natural Compound That Improves Cognitive and Physiological Functions in Animal Models of Neurodegenerative Diseases

Cell-based screening of bioactive compounds has served as an important gateway in drug discovery. In the present report, using human neuroblastoma cells and enrolling an extensive three-step screening of 57 phytochemicals, we have identified caffeic acid phenethyl ester (CAPE) as a potent neurodifferentiating natural compound. Analyses of control and CAPE-induced neurodifferentiated cells revealed: (i) modulation of several key proteins (NF200, MAP-2, NeuN, PSD95, Tuj1, GAP43, and GFAP) involved in neurodifferentiation process; and (ii) attenuation of neuronal stemness (HOXD13, WNT3, and Msh-2) and proliferation-promoting (CDC-20, CDK-7, and BubR1) proteins. We anticipated that the neurodifferentiation potential of CAPE may be beneficial for the treatment of neurodegenerative diseases and tested it using the Drosophila model of Alzheimer’s disease (AD) and mice model of amnesia/loss of memory. In both models, CAPE exhibited improved disease symptoms and activation of physiological functions. Remarkably, CAPE-treated mice showed increased levels of neurotrophin-BDNF, neural progenitor marker-Nestin, and differentiation marker-NeuN, both in the cerebral cortex and hippocampus. Taken together, we demonstrate the differentiation-inducing and therapeutic potential of CAPE for neurodegenerative diseases.

Caffeic acid phenethyl ester counteracts doxorubicin-induced chemobrain in Sprague-Dawley rats: Emphasis on the modulation of oxidative stress and neuroinflammation

Chemotherapy-induced cognitive dysfunction (chemobrain) is one of the major complaints for cancer patients treated with chemotherapy such as Doxorubicin (DOX). The induction of oxidative stress and neuroinflammation were identified as major contributors to such adverse effect. Caffeic acid phenethyl ester (CAPE) is a natural polyphenolic compound, that exhibits unique context-dependent antioxidant activity. It exhibits pro-oxidant effects in cancer cells, while it is a potent antioxidant and cytoprotective in normal cells. The present study was designed to investigate the potential neuroprotective effects of CAPE against DOX-induced cognitive impairment. Chemobrain was induced in Sprague Dawley rats via systemic DOX administration once per week for 4 weeks (2 mg/kg/week, i.p.). CAPE was administered at 10 or 20 μmol/kg/day, i.p., 5 days per week for 4 weeks. Morris water maze (MWM) and passive avoidance tests were used to assess learning and memory functions. Oxidative stress was evaluated via the colorimetric determination of GSH and MDA levels in both hippocampal and prefrontal cortex brain regions. However, inflammatory markers, acetylcholine levels, and neuronal cell apoptosis were assessed in the same brain areas using immunoassays including either ELISA, western blotting or immunohistochemistry. DOX produced significant impairment in learning and memory as indicated by the data generated from MWM and step-through passive avoidance tests. Additionally DOX-triggered oxidative stress as evidenced from the reduction in GSH levels and increased lipid peroxidation. Treatment with DOX resulted in neuroinflammation as indicated by the increase in NF-kB (p65) nuclear translocation in addition to boosting the levels of pro-inflammatory mediators (COX-II/TNF-α) along with the increased levels of glial fibrillary acid protein (GFAP) in the tested tissues. Moreover, DOX reduced acetylcholine levels and augmented neuronal cell apoptosis as supported by the increased active caspase-3 levels. Co-treatment with CAPE significantly counteracted DOX-induced behavioral and molecular abnormalities in rat brain tissues. Our results provide the first preclinical evidence for CAPE promising neuroprotective activity against DOX-induced neurodegeneration and memory deficits.

Evaluation of the neuroprotective potential of caffeic acid phenethyl ester in a cellular model of Parkinson's disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease, and oxidative stress and mitochondrial dysfunction play a major role in the pathogenesis of PD. Since conventional therapeutics are not sufficient for the treatment of PD, the development of new agents with anti-oxidant potential is crucial. Caffeic Acid Phenethyl Ester (CAPE), a biologically active flavonoid of propolis, possesses several biological properties such as immunomodulatory, anti-inflammatory and anti-oxidative. In the present study, we investigated the neuroprotective effects of CAPE against 6-hydroxydopamine (6-OHDA)-induced SH-SY5Y cells. The neuroprotective effects were detected by using cell viability, Annexin V, Hoechst staining, total caspase activity, cell cycle, as well as western blotting. Besides, the anti-oxidative activity was measured by the production of reactive oxygen species and mitochondrial function was determined by measurement of mitochondrial membrane potential (ΔΨm). We found that CAPE significantly increased cell viability and decreased apoptotic cell death (~20%) after 150 μM 6-OHDA exposure following 24 h. 1.25 μM CAPE also prevented 6-OHDA-induced changes in condensed nuclear morphology. Furthermore, treatment with 1.25 μM CAPE increased mitochondrial membrane potential in 6-OHDA-exposed cells. CAPE inhibited 6-OHDA-induced caspase activity (~2 fold) and production of reactive oxygen species. In addition, 150 μM 6-OHDA-induced down-regulation of Bcl-2 and Akt levels and up-regulation of Bax and cleaved caspase-9/caspase-9 levels were partially restored by 1.25 μM CAPE treatment. These results revealed a neuroprotective potential of CAPE against 6-OHDA-induced apoptosis in an in vitro PD model and may be a potential therapeutic candidate for the prevention of neurodegeneration in Parkinson's Disease.

The Impact of Propolis Factor Caffeic Acid Phenethyl-Ester on the Cerebral Vasospasm and Early Brain Damage in the Experimentally Induced Subarachnoid Hemorrhage on Rats

OBJECTIVE

Caffeic acid phenethyl ester (CAPE), a phenolic compound, besides being 1 of the biologically active components of propolis, is a compound with antioxidant, antiinflammatory, antiviral, reperfusion damage prevention, immune stimulant, and carcinostatic, anticancer properties. The aim of this study was to investigate the possible effects of CAPE on cerebral vasospasm and early brain injury, which were experimentally administered intraperitoneally in rats with subarachnoid hemorrhage.

METHODS

Thirty-two Wistar Albino rats weighing 200 to 300 g were used in our study. The rats divided into 3 groups: the control group (n = 10), subarachnoid hemorrhage group (n = 11), and subarachnoid hemorrhage + CAPE group (n = 11). These groups were evaluated according to the Ischemia index in hippocampal CA3 regions and the morphometric analysis of basilar artery diameter after being sacrificed at the end of 72nd hour.

RESULTS

A significant difference was found between group 1 and group 2 for the CA-3 region, it was concluded that early brain damage occurred after subarachnoid hemorrhage. When the neuronal damage in CA-3 region was evaluated between group 2 and group 3, a statistically significant difference was found between the groups. There was a statistically significant difference between group 1 and group 3 in terms of ischemia detection.

CONCLUSIONS

It was shown that CAPE has a preventive effect on early brain injury after subarachnoid hemorrhage and has a positive effect on reducing cerebral vasospasm. Our study is the first study in the literature showing that CAPE inhibits ischemic brain injury following subarachnoid hemorrhage.

Caffeic Acid Phenethyl Ester Inhibits the Proliferation of HEp2 Cells by Regulating Stat3/Plk1 Pathway and Inducing S Phase Arrest

Caffeic acid phenethyl ester (CAPE), an active polyphenolic component of honeybee propolis, has been demonstrated to have many medicinal properties. However, the antitumor effect and mechanism of CAPE on laryngeal carcinoma cells have not been examined. In this study, we treated HEp2 cells with various concentration of CAPE, and the results showed that CAPE can reduce the viability of HEp2 cells with IC50 values of 23.8 ± 0.7 µM for 72 h. Meanwhile, CAPE significantly inhibited activation of signal transducer and activator of transcription (Stat)3 in a concentration dependent manner in HEp2 cells and regulated the expression and transcription of Plk1. AG490, a specific Stat3 inhibitor, not only inhibited the activation and expression of Stat3, but also inhibited the expression of Plk1 in HEp2 cells, so Stat3 was probably involved in the regulation of Plk1 in HEp2 cells. In addition, treatment of CAPE leaded to a blockage of cell cycle in S phase in HEp2 cells. Therefore, CAPE inhibited the proliferation of HEp2 Cells probably by regulating Stat3/Plk1 pathway and inducing S phase arrest.

Lavandula angustifolia biological characteristics: An in vitro study

OBJECTIVE

Lavender is an aromatic shrub belonging to the Lamiaceae family. The flowers and leaves in different forms of extracts are used as herbal medicine. The accumulation of amyloid beta (Aβ) plaques, reduction of acetylcholine due to hyperactivity of acetylcholinesterase, and glutamate neurotoxicity are known to be involved in decreased level of cognitive function. In our previous study, we proved that the aqueous extract of lavender improves learning and memory. This in vitro study was designed to evaluate antiaggregative, antioxidant, and antiacetylcholinesterase activities of the herbal medicine.

METHODS

Thin layer chromatography, high-performance liquid chromatography, thioflavin, atomic force microscope (AFM), Elleman,and 2,2-diphenyl-1-picryl hydrazyl techniques were used for qualitative analysis, quantitative analysis, antiaggregative characteristics, anti-acetylcholinestrase activity and antioxidant activity of the lavender extract, respectively.

RESULTS

We found chromatographic peaks of caffeic acid and luteolin-7-glycosid in the lavender extract. Our results indicated that aqueous extract of lavender dose-dependently inhibits the formation of Aβ aggregate. The AFM technique showed that lavender largely diminished the Aβ fibril formation. We also observed a considerable radical scavenging activity of the extract.

CONCLUSIONS

Prevention of Aβ plaque formation and antioxidant activity along with nontoxic features of the lavender extract promise possible effectiveness of this plant on improving some neurological disorders including Alzheimer's disease.

Repurposing nitrocatechols: 5-Nitro-α-cyanocarboxamide derivatives of caffeic acid and caffeic acid phenethyl ester effectively inhibit aggregation of tau-derived hexapeptide AcPHF6

Polyphenols like caffeic acid and its phenethyl ester have been associated with potent anti-aggregating activity. Accordingly, we screened a library of polyphenols and synthetic derivatives thereof for their capacity to inhibit tau-aggregation using a thioflavin T-based fluorescence method. Our results show that the nitrocatechol scaffold is required for a significant anti-aggregating activity, which is enhanced by introducing bulky substituents at the side chain. A remarkable increase in activity was observed for α-cyanocarboxamide derivatives 26-27. Molecular docking studies showed that the amide bond provides superior conformational stability in the steric zipper assembly of tau, which drives the increase in activity. We also found that derivatives 24-27 were potent chelators of copper(II) - a property of pharmacological significance in abnormal protein aggregation. These small molecules can provide promising leads to develop new drugs for tauopathies and AD. These findings open a new window on the repurposing of nitrocatechols beyond their established role as catechol-O-methyltransferase inhibitors.

Neuroprotective Effect of Caffeic Acid Phenethyl Ester in A Mouse Model of Alzheimer's Disease Involves Nrf2/HO-1 Pathway

Alzheimer's disease (AD) is a progressive pathology, where dementia symptoms gradually worsen over a number of years. The hallmarks of AD, such as amyloid β-peptide (Aβ) in senile plaque and neurofibrillary tangles, are strongly intertwined with oxidative stress, which is considered one of the common effectors of the cascade of degenerative events. The endogenous nuclear factor erythroid 2-related factor 2 (Nrf2) is the "master regulator" of the antioxidant response and it is known as an indicator and regulator of oxidative stress. The present study aimed to determine the potential neuroprotective activity of caffeic acid phenethyl ester (CAPE), a polyphenolic compound abundant in honeybee, against the neurotoxicity of Aβ_1-42 oligomers (AβO) in mice. An intracerebroventricular (i.c.v.) injection of AβO into the mouse brain triggered increased reactive oxygen species levels, neurodegeneration, neuroinflammation, and memory impairment. In contrast, the intraperitoneal administration of CAPE (10 mg/kg) after i.c.v. AβO-injection counteracted oxidative stress accompanied by an induction of Nrf2 and heme oxygenase-1 via the modulation of glycogen synthase kinase 3β in the hippocampus of mice. Additionally, CAPE treatment decreased AβO-induced neuronal apoptosis and neuroinflammation, and improved learning and memory, protecting mice against the decline in spatial cognition. Our findings demonstrate that CAPE could potentially be considered as a promising neuroprotective agent against progressive neurodegenerative diseases such as AD.

Neurobehavioral and Antioxidant Effects of Ethanolic Extract of Yellow Propolis

Propolis is a resin produced by bees from raw material collected from plants, salivary secretions, and beeswax. New therapeutic properties for the Central Nervous System have emerged. We explored the neurobehavioral and antioxidant effects of an ethanolic extract of yellow propolis (EEYP) rich in triterpenoids, primarily lupeol and β-amyrin. Male Wistar rats, 3 months old, were intraperitoneally treated with Tween 5% (control), EEYP (1, 3, 10, and 30 mg/kg), or diazepam, fluoxetine, and caffeine (positive controls) 30 min before the assays. Animals were submitted to open field, elevated plus maze, forced swimming, and inhibitory avoidance tests. After behavioral tasks, blood samples were collected through intracardiac pathway, to evaluate the oxidative balance. The results obtained in the open field and in the elevated plus maze assay showed spontaneous locomotion preserved and anxiolytic-like activity. In the forced swimming test, EEYP demonstrated antidepressant-like activity. In the inhibitory avoidance test, EEYP showed mnemonic activity at 30 mg/kg. In the evaluation of oxidative biochemistry, the extract reduced the production of nitric oxide and malondialdehyde without changing level of total antioxidant, catalase, and superoxide dismutase, induced by behavioral stress. Our results highlight that EEYP emerges as a promising anxiolytic, antidepressant, mnemonic, and antioxidant natural product.

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.

Recent progress towards an effective treatment of amyotrophic lateral sclerosis using the SOD1 mouse model in a preclinical setting

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal and incurable neurodegenerative disorder. Motor neurone degeneration can be caused by genetic mutation but the exact etiology of the disease, particularly for sporadic illness, still remains unclear. Therapeutics which target known pathogenic mechanisms involved in ALS, such as protein aggregation, oxidative stress, apoptosis, inflammation, endoplasmic reticulum stress and mitochondria dysfunction, are currently being pursued in order to provide neuroprotection which may be able to slow down, or perhaps even halt, disease progression. This present review focuses on the compounds which have been recently evaluated using the SOD1 mouse model, the most widely used preclinical model for ALS research.

Novel antidepressant-like activity of caffeic Acid phenethyl ester is mediated by enhanced glucocorticoid receptor function in the hippocampus

Caffeic acid phenethyl ester (CAPE) is an active component of propolis that has a variety of potential pharmacological effects. Although we previously demonstrated that propolis has antidepressant-like activity, the effect of CAPE on this activity remains unknown. The present study assessed whether treatment with CAPE (5, 10, and 20 µmol/kg for 21 days) has an antidepressant-like effect in mice subjected to chronic unpredictable stress via tail suspension (TST) and forced swim (FST) tests. CAPE administration induced behaviors consistent with an antidepressant effect, evidenced by decreased immobility in the TST and FST independent of any effect on serum corticosterone secretion. Western blots, conducted subsequent to behavioral assessment, revealed that CAPE significantly decreased glucocorticoid receptor phosphorylation at S234 (pGR(S234)), resulting in an increased pGR(S220/S234) ratio. We also observed negative correlations between pGR(S220)/(S234) and p38 mitogen-activated protein kinase (p38MAPK) phosphorylation, which was decreased by CAPE treatment. These findings suggest that CAPE treatment exerts an antidepressant-like effect via downregulation of p38MAPK phosphorylation, thereby contributing to enhanced GR function.

Caffeic acid phenethyl ester (CAPE) protects PC12 cells from MPP+ toxicity by inducing the expression of neuron-typical proteins

Neurite loss is an early event in neurodegenerative diseases; therefore, the regeneration of the network of neurites constitutes an interesting strategy of treatment for such disorders. Neurotrophic factors play a critical role in neuronal regeneration, but their clinical use is limited by their inability to cross the blood brain barrier. Oxidative and inflammatory events are implicated in neurodegeneration and antioxidant compounds have been suggested as potential neuroprotectors. The protective potential of CAPE (caffeic acid phenethyl ester) has been shown in different models of neurotoxicity (in vitro and in vivo) and it has been associated with immune-modulatory, antioxidant and anti-inflammatory properties; however, other mechanisms might be involved. The present study demonstrates that CAPE protects PC12 cells from the cellular death induced by the dopaminergic neurotoxin MPP(+) by increasing the network of neurites. Results showed that CAPE induced the formation, elongation and ramification of neurites in PC12 cells non-stimulated with NGF (nerve growth factor) and inhibited the shortage of neurites induced by the dopaminergic neurotoxin. These effects were associated with increased expression of neuron-typical proteins responsible for axonal growth (GAP-43) and synaptogenesis (synaptophysin and synapsin I). It is noteworthy that, unlike neurotrophins, CAPE would be able to cross the blood brain barrier and exert its neurotrophic effects in the brain. This study corroborates the therapeutic potential of CAPE in neurodegenerative diseases while proposes the involvement of neuroplasticity in the mechanism of neuroprotection.

Caffeic acid phenethyl ester and therapeutic potentials

Caffeic acid phenethyl ester (CAPE) is a bioactive compound of propolis extract. The literature search elaborates that CAPE possesses antimicrobial, antioxidant, anti-inflammatory, and cytotoxic properties. The principal objective of this review article is to sum up and critically assess the existing data about therapeutic effects of CAPE in different disorders. The findings elaborate that CAPE is a versatile therapeutically active polyphenol and an effective adjuvant of chemotherapy for enhancing therapeutic efficacy and diminishing chemotherapy-induced toxicities.

Methyl p-Hydroxycinnamate Suppresses Lipopolysaccharide-Induced Inflammatory Responses through Akt Phosphorylation in RAW264.7 Cells

Derivatives of caffeic acid have been reported to possess diverse pharmacological properties such as anti-inflammatory, anti-tumor, and neuroprotective effects. However, the biological activity of methyl p-hydroxycinnamate, an ester derivative of caffeic acid, has not been clearly demonstrated. This study aimed to elucidate the anti-inflammatory mechanism of methyl p-hydroxycinnamate in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Methyl p-hydroxycinnamate significantly inhibited LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE₂ and the protein expression of iNOS and COX-2. Methyl p-hydroxycinnamate also suppressed LPS-induced overproduction of pro-inflammatory cytokines such as IL-1β and TNF-α. In addition, methyl p-hydroxycinnamate significantly suppressed LPS-induced degradation of IκB, which retains NF-κB in the cytoplasm, consequently inhibiting the transcription of pro-inflammatory genes by NF-κB in the nucleus. Methyl p-hydroxycinnamate exhibited significantly increased Akt phosphorylation in a concentration-dependent manner. Furthermore, inhibition of Akt signaling pathway with wortmaninn abolished methyl p-hydroxycinnamate-induced Akt phosphorylation. Taken together, the present study clearly demonstrates that methyl p-hydroxycinnamate exhibits anti-inflammatory activity through the activation of Akt signaling pathway in LPS-stimulated RAW264.7 macrophage cells.

Phenolic acid intake, delivered via moderate champagne wine consumption, improves spatial working memory via the modulation of hippocampal and cortical protein expression/activation

AIMS

While much data exist for the effects of flavonoid-rich foods on spatial memory in rodents, there are no such data for foods/beverages predominantly containing hydroxycinnamates and phenolic acids. To address this, we investigated the effects of moderate Champagne wine intake, which is rich in these components, on spatial memory and related mechanisms relative to the alcohol- and energy-matched controls.

RESULTS

In contrast to the isocaloric and alcohol-matched controls, supplementation with Champagne wine (1.78 ml/kg BW, alcohol 12.5% vol.) for 6 weeks led to an improvement in spatial working memory in aged rodents. Targeted protein arrays indicated that these behavioral effects were paralleled by the differential expression of a number of hippocampal and cortical proteins (relative to the isocaloric control group), including those involved in signal transduction, neuroplasticity, apoptosis, and cell cycle regulation. Western immunoblotting confirmed the differential modulation of brain-derived neurotrophic factor, cAMP response-element-binding protein (CREB), p38, dystrophin, 2',3'-cyclic-nucleotide 3'-phosphodiesterase, mammalian target of rapamycin (mTOR), and Bcl-xL in response to Champagne supplementation compared to the control drink, and the modulation of mTOR, Bcl-xL, and CREB in response to alcohol supplementation.

INNOVATION

Our data suggest that smaller phenolics such as gallic acid, protocatechuic acid, tyrosol, caftaric acid, and caffeic acid, in addition to flavonoids, are capable of exerting improvements in spatial memory via the modulation in hippocampal signaling and protein expression.

CONCLUSION

Changes in spatial working memory induced by the Champagne supplementation are linked to the effects of absorbed phenolics on cytoskeletal proteins, neurotrophin expression, and the effects of alcohol on the regulation of apoptotic events in the hippocampus and cortex.

Caffeic acid phenethyl ester prevents apoptotic cell death in the developing rat brain after pentylenetetrazole-induced status epilepticus

Population-based studies suggest that seizure incidence is highest during the first year of life, and early-life seizures frequently result in the development of epilepsy and behavioral alterations later in life. The early-life insults like status epilepticus often lead to epileptogenesis, a process in which initial brain injury triggers cascades of molecular, cellular, and network changes and eventually spontaneous seizures. Caffeic acid phenethyl ester is an active component of propolis obtained from honeybees and has neuroprotective properties. The aim of this study was to investigate whether caffeic acid phenethyl ester exerts neuroprotective effects on the developing rat brain after status epilepticus. Twenty-one dams reared Wistar male rats, and 21-day-old rats were divided into three groups: control group, pentylenetetrazole-induced status epilepticus group, and caffeic acid phenethyl ester-treated group. Status epilepticus was induced on the first day of experiment. Caffeic acid phenethyl ester injections (30 mg/kg intraperitoneally) started 40 min after the tonic phase of status epilepticus was reached, and the injections of caffeic acid phenethyl ester were repeated over 5 days. Rats were sacrificed, and brain tissues were collected on the 5th day of experiment after the last injection of caffeic acid phenethyl ester. Apoptotic cell death was evaluated. Histopathological examination showed that caffeic acid phenethyl ester significantly preserved the number of neurons in the CA1, CA3, and dentate gyrus regions of the hippocampus and the prefrontal cortex. It also diminished apoptosis in the hippocampus and the prefrontal cortex. In conclusion, this experimental study suggests that caffeic acid phenethyl ester administration may be neuroprotective in status epilepticus in the developing rat brain.

Protective effects of caffeic acid phenethyl ester on ifosfamide-induced central neurotoxicity in rats

BACKGROUND

The aim of this study was to establish the protective effect of caffeic acid phenethyl ester (CAPE) against the ifosfamide (IFOS)-induced central neurotoxicity in rats and to determine the changes in oxidant-antioxidant status of brain tissue.

METHOD

A total of 35 Wistar rats (aged 7-12 days) were used in the experiments. The study comprised of five groups. Control untreated rats (n = 7) belonged to group 1; group 2 was given intraperitoneal (IP) injection of CAPE alone (10 µmol/kg; n = 7); group 3 was treated with single IP injection of IFOS (500 mg/kg; n = 7); group 4 was treated for 2 days with IP administration of CAPE (10 µmol/kg) beginning from one day before single IP injection of IFOS (n = 7); and group 5 was treated with saline and 10% ethanol. At the 24th hour of IFOS treatment, brain tissues were removed for analysis.

RESULTS

The brain catalase activity was lower in IFOS group than the other groups (p < 0.05). The levels of malondialdehyde (MDA) and protein carbonyl content in brain tissue were higher in IFOS group than the control, CAPE, ethanol, and IFOS + CAPE groups (p < 0.05). There was no significant difference between MDA and protein carbonyl content of control, CAPE, ethanol, and IFOS + CAPE groups. Immunohistochemistry showed marked activation of caspase 3 in the IFOS group at 24 h after treatment.

CONCLUSION

This study revealed that pretreatment with CAPE might protect brain tissue against IFOS-induced central neurotoxicity. CAPE could be an effective course of therapy to enhance therapeutic efficacy and to lessen IFOS toxicity in clinical chemotherapy.

Design, synthesis and pharmacological evaluation of (E)-3,4-dihydroxy styryl sulfonamides derivatives as multifunctional neuroprotective agents against oxidative and inflammatory injury

A novel class of (E)-3,4-dihydroxy styryl sulfonamides and their 3,4-diacetylated derivatives as caffeic acid phenethyl ester (CAPE) analogs was designed and prepared for improving stability and solubility of the lead compound. Their neuroprotective properties were assessed by several models. The results showed that target compounds displayed positive free radical quenching abilities, superior to that of CAPE. Compounds 6j-k and 7j-k demonstrated remarkable protection effects against damage induced by hydrogen peroxide which were apparently stronger than that of CAPE. Most of target compounds could inhibit nitric oxide production. Additionally, target compounds showed high blood-brain barrier permeability.

Caffeic acid phenethyl ester ameliorates cadmium-induced kidney mitochondrial injury

This study examined whether caffeic acid phenethyl ester (CAPE) can protect kidney mitochondria against cadmium toxicity. Kidney mitochondria isolated from Wistar rat were exposed to cadmium and/or CAPE at various concentrations. Mitochondrial function, ultrastructure and oxidative stress status were determined. Cadmium exposure resulted in mitochondrial swelling, dissipation of membrane potential, overproduction of reactive oxygen species, and impaired ultrastructure. The injury was accompanied by an increase in mitochondrial nitric oxide and malondialdehyde levels as well as a decrease in superoxide dismutase activity and antioxidant thiols. Pretreatment with CAPE ameliorated all the changes caused by cadmium. The results suggest a promising role for CAPE as mitochondria-targeted antioxidant to combat the renal toxicity of cadmium.

Caffeic acid phenethyl ester extends survival of a mouse model of amyotrophic lateral sclerosis

There is currently very limited effective pharmacological treatment for amyotrophic lateral sclerosis. Recent evidence suggests that caffeic acid phenethyl ester has strong anti-inflammatory, anti-oxidative, and anti-neuronal death properties; thus, the present study tested the effects of caffeic acid phenethyl ester in mice expressing a mutant superoxide dismutase (SOD1(G93A)) linked to human amyotrophic lateral sclerosis. Administration of caffeic acid phenethyl ester after symptom onset significantly increased the post-onset survival and lifespan of SOD1(G93A) mice. Moreover, immunohistochemical analysis detected less activation of microglia and astrocytes and higher motor neuron counts at an early symptomatic stage (7 days following onset) in the spinal cords of SOD1(G93A) mice given caffeic acid phenethyl ester treatment. Additionally, lower levels of phosphorylated p38, a mitogen-activated protein kinase that is involved in both inflammation and neuronal death, were observed in the spinal cords of SOD1(G93A) mice treated with caffeic acid phenethyl ester for 7 days. These results indicate that caffeic acid phenethyl ester may represent a novel and effective therapeutic for the treatment of amyotrophic lateral sclerosis, and these significant neuroprotective effects observed in a commonly used amyotrophic lateral sclerosis mouse model validate the therapeutic potential of caffeic acid phenethyl ester for slowing disease progression by attenuating the neuroinflammation and motor neuron cell death associated with clinical amyotrophic lateral sclerosis pathology.

Anti-inflammatory Activity of 1-docosanoyl Cafferate Isolated from Rhus verniciflua in LPS-stimulated BV2 Microglial Cells

Although various derivatives of caffeic acid have been reported to possess a wide variety of biological activities such as protection of neuronal cells against excitotoxicity, the biological activity of 1-docosanoyl cafferate (DC) has not been examined. The objective of the present study was to evaluate the anti-inflammatory effects of DC, isolated from the stem bark of Rhus verniciflua, on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Pretreatment of cells with DC significantly attenuated LPS-induced NO production, and mRNA and protein expression of iNOS in a concentration-dependent manner. DC also significantly suppressed LPS-induced release of cytokines such as TNF-α and IL-1β . Consistent with the decrease in cytokine release, DC dose-dependently and significantly attenuated LPS-induced mRNA expression of these cytokines. Furthermore, DC significantly suppressed LPS-induced degradation of IKB, which retains NF-kB in the cytoplasm. Therefore, nuclear translocation of NF-kB induced by LPS stimulation was significantly suppressed with DC pretreatment. Taken together, the present study suggests that DC exerts its anti-inflammatory activity through the suppression of NF-kB translocation to the nucleus.

Effects of caffeic acid phenethyl ester on thioacetamide-induced hepatic encephalopathy in rats

Hepatic encephalopathy (HE) is a major neurological complication secondary to severe liver failure. The aim of the present study was to examine the possible neuroprotective effects of caffeic acid phenethyl ester (CAPE) with or without laxative treatment against thioacetamide-induced HE by investigating behavioral and motor activities in rats as well as blood ammonia level and oxidant-antioxidant parameters of cortex, brain stem and cerebellum. After induction of HE by thioacetamide, the rats were treated with lactulose, CAPE (CAPE treatment was started one day before the first dose of thioacetamide) or CAPE plus lactulose. The behavioral and motor scales were measured at the 54th hour after the first thioacetamide injection, the blood samples and brains were taken under anesthesia at the 60th hour for biochemical analysis. The survival rates were 37.5% in HE group, 70% in HE+lactulose group, 80% in HE+CAPE group, and 100% in HE+CAPE+lactulose group. Increased ammonia, ALT and AST levels in blood along with impaired sensory-motor behavior tests were reversed to proximate control values in CAPE+lactulose treated group. There were increased lipid peroxidation and protein oxidation and decreased antioxidant enzyme activities in almost all brain parts of HE group. CAPE or lactulose treatment alone ameliorated those oxidant and antioxidant parameters; however, CAPE treatment together with lactulose reversed them to almost control level. In conclusion, thioacetamide-induced HE injury in rats was reversed almost fully by CAPE and laxative combination. There was no death in CAPE and laxative treated group animals and it may be due to the direct neuroprotective effect of CAPE together with the prevention of the body from ammonia production.

The ultrastructural and biochemical evidences of the beneficial effects of chronic caffeic acid phenethyl ester and melatonin administration on brain and cerebellum of aged rats

Nervous system is highly vulnerable to the deleterious effects of age-related oxidative stress. A large body of researches has consistently confirmed the implication of free radicals both in normal cerebral ageing and ageing-related pathologies. In the present study, in addition to the light and electron microscopic pictures of brain and cerebellum of young, old and antioxidant administered old Sprague-Dawley rats, pro-oxidant status was evaluated in terms of measurements of total glutathione, lipid peroxidation (malondialdehyde) and activities of superoxide dismutase, catalase and glutathione peroxidase. Taking the results together, we suggest that supplemental administration of caffeic acid phenethyl ester and melatonin is beneficial in delaying age-related cellular damage in nervous system.

Effect of caffeic acid and rofecoxib and their combination against intrastriatal quinolinic acid induced oxidative damage, mitochondrial and histological alterations in rats

Oxidative stress has long been implicated in the neurotoxic effects of glutamate acting through N-methyl-D-aspartate (NMDA) receptors. Therefore, present study has been designed to explore the effect of rofecoxib and caffeic acid on the involvement of oxidative stress, mitochondrial dysfunction and neuronal linked with NMDA receptor-mediated excitotoxicity. Caffeic acid, is a well-known antioxidant flavanoid, implicate anti-inflammatory and immunomodulatory like actions. The present study is an attempt to investigate the antioxidant-like effect of caffeic acid and rofecoxib and their combination against QA-induced oxidative damage, mitochondrial dysfunction and histological alterations. Intrastriatal injection of quinolinic acid (300 nmol) significantly increased oxidative stress (raised lipid peroxidation, nitrite concentration, depleted SOD and catalase), altered mitochondrial complex enzyme activities and histological alteration in the ex vivo striatum. Caffeic acid (5 and 10 mg/kg, p.o.) and rofecoxib (10 and 20 mg/kg, p.o.) treatment for 21 days significantly attenuated oxidative damage and impairment in mitochondrial activities of complex enzymes in the ex vivo striatum. Further, combination of sub effective doses of rofecoxib (10 mg/kg, p.o.) and caffeic acid (5 mg/kg, p.o.) potentiated their protective effect which was significant as compared to their effect per se. The present study suggests the therapeutic effect of caffeic acid and rofecoxib combination against QA-induced ex vivo oxidative damage, mitochondrial and histological alterations in rats.

Brain oxidative stress as basic target of antioxidant traditional oriental medicines

Prevention and amelioration of Mibyou (sub-healthy condition) is the critical target for disease prevention including age-related diseases and cancer although the Mibyou condition is not yet pathologically defined. Since the oxidative stress is an underlying basic etiology associated with many diseases and aging, the psychologically induced oxidative stress, especially in the brain was supposed as one of the pathology of Mibyou. Several traditional herbal prescriptions applied for the brain disorder were found effective to prevent cerebral oxidative stress induced by ischemia/reperfusion and also under psychological distress produced by whiskers cut in mice. Shengmai San comprising three herbs, Panax ginseng, Ophiopogon japonicus and Schisandra chinensis is a traditional herbal medicine formula having a long history of using as a remedy and clinical prescription to treat coronal heart diseases. Multifunctional aspect of traditional herbal prescription was discussed in terms of preventing oxidative injury in the brain using Shengmai San as a typical prescription.