Neuroprotective Potential of Caffeic Acid Phenethyl Ester (CAPE) in CNS Disorders: Mechanistic and Therapeutic Insights

Clinical Insights on Caloric Restriction Mimetics for Mitigating Brain Aging and Related Neurodegeneration

Aging, an inevitable physiological process leading to a progressive decline in bodily functions, has been an abundantly researched domain with studies attempting to slow it down and reduce its debilitating effects. Investigations into the cellular and molecular pathways associated with aging have allowed the formulation of therapeutic strategies. Of these, caloric restriction (CR) has been implicated for its role in promoting healthy aging by modulating key molecular targets like Insulin/IGF-1, mTOR, and sirtuins. However, CR requires dedication and commitment to a strict regimen which poses a difficulty in maintaining consistency. To maneuver around cumbersome diets, Caloric Restriction Mimetics (CRMs) have emerged as promising alternatives by mimicking the beneficial effects of CR. This review elucidates the molecular foundations enabling CRMs like rapamycin, metformin, resveratrol, spermidine, and many more to function as suitable anti-aging molecules. Moreover, it explores clinical trials (retrieved from the clinicaltrials.gov database) aimed at demonstrating the efficacy of CRMs as effective candidates against age-related neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.

The neuroprotective effects of caffeic acid phenethyl ester against methamphetamine-induced neurotoxicity

Methamphetamine (METH) is a highly abused substance on a global scale and has the capacity to elicit toxicity within the central nervous system. The neurotoxicity induced by METH encompasses neuronal degeneration and cellular demise within the substantia nigra-striatum and hippocampus. Caffeic acid phenethyl ester (CAPE), a constituent of propolis, is a diminutive compound that demonstrates antioxidative and anti-inflammatory characteristics. Numerous investigations have demonstrated the safeguarding effects of CAPE in various neurodegenerative ailments. Our hypothesis posits that CAPE may exert a neuroprotective influence on METH-induced neurotoxicity via specific mechanisms. In order to validate the hypothesis, a series of experimental techniques including behavioral tests, immunofluorescence labeling, RNA sequencing, and western blotting were employed to investigate the neurotoxic effects of METH and the potential protective effects of CAPE. The results of our study demonstrate that CAPE effectively ameliorates cognitive memory deficits and anxiety symptoms induced by METH in mice. Furthermore, CAPE has been observed to attenuate the upregulation of neurotoxicity-associated proteins that are induced by METH exposure and also reduced the loss of hippocampal neurons in mice. Moreover, transcriptomics analysis was conducted to determine alterations in gene expression within the hippocampus of mice. Subsequently, bioinformatics analysis was employed to investigate the divergent outcomes and identify potential key genes. Interferon-stimulated gene 15 (ISG15) was successfully identified and confirmed through RT-qPCR, western blotting, and immunofluorescence techniques. Our research findings unequivocally demonstrated the neuroprotective effect of CAPE against METH-induced neurotoxicity, with ISG15 may have an important role in the underlying protective mechanism. These results offer novel perspectives on the treatment of METH-induced neurotoxicity.

Study on network pharmacology of Ginkgo biloba extract against ischaemic stroke mechanism and establishment of UPLC-MS/MS methods for simultaneous determination of 19 main active components

INTRODUCTION

Ginkgo biloba extract (GBE) is an effective substance from traditional Chinese medicine (TCM) G. biloba for treating ischaemic stroke (IS). However, its active ingredients and mechanism of action remain unclear.

OBJECTIVES

This study aimed to reveal the potential active component group and possible anti-IS mechanism of GBE.

MATERIALS AND METHODS

The network pharmacology method was used to reveal the possible anti-IS mechanism of these active ingredients in GBE. An ultra-high-performance liquid chromatography triple quadrupole electrospray tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous detection of the active ingredients of GBE.

RESULTS

The active components of GBE anti-IS were screened by literature integration. Network pharmacology results showed that the anti-IS effect of GBE is achieved through key active components such as protocatechuic acid, bilobalide, ginkgolide A, and so on. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the possible anti-IS mechanism of GBE is regulating the PI3K-Akt signalling pathway and other signal pathways closely related to inflammatory response and apoptosis regulation combined with AKT1, MAPK, TNF, ALB, CASP3, and other protein targets. Nineteen main constituents in seven batches of GBE were successfully analysed using the established UPLC-MS/MS method, and the results showed that the content of protocatechuic acid, gallic acid, ginkgolide A, and so forth was relatively high, which was consistent with network pharmacology results, indicating that these ingredients may be the key active anti-IS ingredients of GBE.

CONCLUSION

This study revealed the key active components and the anti-IS mechanism of GBE. It also provided a simple and sensitive method for the quality control of related preparations.

A clinical study and future prospects for bioactive compounds and semi-synthetic molecules in the therapies for Huntington's disease

A neurodegenerative disorder (ND) refers to Huntington's disease (HD) which affects memory loss, weight loss, and movement dysfunctions such as chorea and dystonia. In the striatum and brain, HD most typically impacts medium-spiny neurons. Molecular genetics, excitotoxicity, oxidative stress (OS), mitochondrial, and metabolic dysfunction are a few of the theories advanced to explicit the pathophysiology of neuronal damage and cell death. Numerous in-depth studies of the literature have supported the therapeutic advantages of natural products in HD experimental models and other treatment approaches. This article briefly discusses the neuroprotective impacts of natural compounds against HD models. The ability of the discovered natural compounds to suppress HD was tested using either in vitro or in vivo models. Many bioactive compounds considerably lessened the memory loss and motor coordination brought on by 3-nitropropionic acid (3-NP). Reduced lipid peroxidation, increased endogenous enzymatic antioxidants, reduced acetylcholinesterase activity, and enhanced mitochondrial energy generation have profoundly decreased the biochemical change. It is significant since histology showed that therapy with particular natural compounds lessened damage to the striatum caused by 3-NP. Moreover, natural products displayed varying degrees of neuroprotection in preclinical HD studies because of their antioxidant and anti-inflammatory properties, maintenance of mitochondrial function, activation of autophagy, and inhibition of apoptosis. This study highlighted about the importance of bioactive compounds and their semi-synthetic molecules in the treatment and prevention of HD.

Parvalbumin interneurons dysfunction is potentially associated with FαMNs decrease and NRG1-ErbB4 signaling inhibition in spinal cord in amyotrophic lateral sclerosis

OBJECTIVE

To investigate the alteration of PV interneurons in ALS mainly focusing its dynamic changes and its relationship with motor neurons and ErbB4 signaling.

METHODS

SOD1G93A mice were used as ALS model. ALS animals were divided into different groups according to birth age: symptomatic prophase (50~60 days), symptomatic phase (90~100 days), and symptomatic progression (130~140 days). Immunofluorescence was performed for measurement of PV-positive interneurons, MMP-9, ChAT, NeuN and ErbB4. RT-qPCR and western blot were used to determine the expression of PV and MMP-9.

RESULTS

PV expression was remarkably higher in the anterior horn of gray matter compared with posterior horn and area in the middle of gray matter in control mice. In ALS mice, PV, MMP-9 and ErbB4 levels were gradually decreased along with onset. PV, MMP-9 and ErbB4 levels in ALS mice were significantly down-regulated than control mice after onset, indicating the alteration of PV interneurons, FαMNs and ErbB4. SαMNs levels only decreased remarkably at symptomatic progression in ALS mice compared with control mice, while γMNs levels showed no significant change during whole period in all mice. MMP-9 and ErbB4 were positively correlated with PV. NRG1 treatment significantly enhanced the expression of ErBb4, PV and MMP-9 in ALS mice.

CONCLUSION

PV interneurons decrease is along with FαMNs and ErbB4 decrease in ALS mice.

Cistus albidus L.-Review of a Traditional Mediterranean Medicinal Plant with Pharmacological Potential

Cistus albidus L. (Cistaceae) is a medicinal plant that has been used therapeutically since ancient times in the Mediterranean basin for its important pharmacological properties. The ability of C. albidus to produce large quantities of a wide range of natural metabolites makes it an attractive source of raw material. The main constituents with bioactive functions that exert pharmacological effects are terpenes and polyphenols, with more than 200 identified compounds. The purpose of this review is to offer a detailed account of the botanical, ethnological, phytochemical, and pharmacological characteristics of C. albidus with the aim of encouraging additional pharmaceutical investigations into the potential therapeutic benefits of this medicinal plant. This review was carried out using organized searches of the available literature up to July 2023. A detailed analysis of C. albidus confirms its traditional use as a medicinal plant. The outcome of several studies suggests a deeper involvement of certain polyphenols and terpenes in multiple mechanisms such as inflammation and pain, with a potential application focus on neurodegenerative diseases and disorders. Other diseases such as prostate cancer and leukemia have already been researched with promising results for this plant, for which no intoxication has been reported in humans.

Caffeic Acid Phenethyl Ester Suppresses Oxidative Stress and Regulates M1/M2 Microglia Polarization via Sirt6/Nrf2 Pathway to Mitigate Cognitive Impairment in Aged Mice following Anesthesia and Surgery

Postoperative cognitive dysfunction (POCD) is a severe neurological complication after anesthesia and surgery. However, there is still a lack of effective clinical pharmacotherapy due to its unclear pathogenesis. Caffeic acid phenethyl ester (CAPE), which is obtained from honeybee propolis and medicinal plants, shows powerful antioxidant, anti-inflammatory, and immunomodulating properties. In this study, we aimed to evaluate whether CAPE mitigated cognitive impairment following anesthesia and surgery and its potential underlying mechanisms in aged mice. Here, isoflurane anesthesia and tibial fracture surgery were used as the POCD model, and H2O2-induced BV2 cells were established as the microglial oxidative stress model. We revealed that CAPE pretreatment suppressed oxidative stress and promoted the switch of microglia from the M1 to the M2 type in the hippocampus, thereby ameliorating cognitive impairment caused by anesthesia and surgery. Further investigation indicated that CAPE pretreatment upregulated hippocampal Sirt6/Nrf2 expression after anesthesia and surgery. Moreover, mechanistic studies in BV2 cells demonstrated that the potent effects of CAPE pretreatment on reducing ROS generation and promoting protective polarization were attenuated by a specific Sirt6 inhibitor, OSS_128167. In summary, our findings opened a promising avenue for POCD prevention through CAPE pretreatment that enhanced the Sirt6/Nrf2 pathway to suppress oxidative stress as well as favor microglia protective polarization.

Cellular Stress Response (Hormesis) in Response to Bioactive Nutraceuticals with Relevance to Alzheimer Disease

Significance: Alzheimer's disease (AD) is the most common form of dementia associated with aging. As the large Baby Boomer population ages, risk of developing AD increases significantly, and this portion of the population will increase significantly over the next several decades. Recent Advances: Research suggests that a delay in the age of onset by 5 years can dramatically decrease both the incidence and cost of AD. In this review, the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in AD is examined in the context of heme oxygenase-1 (HO-1) and biliverdin reductase-A (BVR-A) and the beneficial potential of selected bioactive nutraceuticals. Critical Issues: Nrf2, a transcription factor that binds to enhancer sequences in antioxidant response elements (ARE) of DNA, is significantly decreased in AD brain. Downstream targets of Nrf2 include, among other proteins, HO-1. BVR-A is activated when biliverdin is produced. Both HO-1 and BVR-A also are oxidatively or nitrosatively modified in AD brain and in its earlier stage, amnestic mild cognitive impairment (MCI), contributing to the oxidative stress, altered insulin signaling, and cellular damage observed in the pathogenesis and progression of AD. Bioactive nutraceuticals exhibit anti-inflammatory, antioxidant, and neuroprotective properties and are potential topics of future clinical research. Specifically, ferulic acid ethyl ester, sulforaphane, epigallocatechin-3-gallate, and resveratrol target Nrf2 and have shown potential to delay the progression of AD in animal models and in some studies involving MCI patients. Future Directions: Understanding the regulation of Nrf2 and its downstream targets can potentially elucidate therapeutic options for delaying the progression of AD. Antioxid. Redox Signal. 38, 643-669.

Nutraceuticals and phytotherapeutics for holistic management of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis" (ALS) is a progressive neuronal disorder that affects sensory neurons in the brain and spinal cord, causing loss of muscle control. Moreover, additional neuronal subgroups as well as glial cells such as microglia, astrocytes, and oligodendrocytes are also thought to play a role in the aetiology. The disease affects upper motor neurons and lowers motor neurons and leads to that either lead to muscle weakness and wasting in the arms, legs, trunk and periventricular area. Oxidative stress, excitotoxicity, programmed cell death, altered neurofilament activity, anomalies in neurotransmission, abnormal protein processing and deterioration, increased inflammation, and mitochondrial dysfunction may all play a role in the progression of ALS. There are presently hardly FDA-approved drugs used to treat ALS, and they are only beneficial in slowing the progression of the disease and enhancing functions in certain individuals with ALS, not really in curing or preventing the illness. These days, researchers focus on understanding the pathogenesis of the disease by targeting several mechanisms aiming to develop successful treatments for ALS. This review discusses the epidemiology, risk factors, diagnosis, clinical features, pathophysiology, and disease management. The compilation focuses on alternative methods for the management of symptoms of ALS with nutraceuticals and phytotherapeutics.

Anxiety and Metabolic Disorders: The Role of Botanicals

Anxiety and anxiety-related disorders are becoming more evident every day, affecting an increasing number of people around the world. Metabolic disorders are often associated with anxiety. Furthermore, anxiety branches into metabolic disorders by playing multiple roles as a cofactor, symptom, and comorbidity. Taken together, these considerations open the possibility of integrating the therapy of metabolic disorders with specific drugs for anxiety control. However, anxiolytic compounds often cause disabling effects in patients. The main goal could be to combine therapeutic protocols with compounds capable of reducing side effects while performing multiple beneficial effects. In this article we propose a group of bioactive ingredients called botanicals as a healthy supplement for the treatment of metabolic disorders related to anxiety.

Melatonin Induces Autophagy in Amyotrophic Lateral Sclerosis Mice via Upregulation of SIRT1

Amyotrophic lateral sclerosis (ALS) is the neurodegenerative disease that leads to the motor dysfunction damaged by both upper and lower motor neurons. The etiology and pathogenesis of ALS hasn't completely been understood yet up to now, the current study suggests that autophagy plays an important role in the development of ALS. Meanwhile, melatonin is found to inhibit the progression of ALS. To this end, this study aimed to investigate the potential relation between melatonin and autophagy in ALS. The in vivo model of ALS was established to investigate the effects of melatonin in ALS. The mRNA expressions were performed to detect by RT-qPCR, and the protein levels were tested by western blot and immunofluorescence histochemistry staining. The inflammatory cytokine was applied to detect by ELISA. The results showed that melatonin dose-dependently reversed the ALS-induced survival time shortened, weight loss and rotating rod latency decrease. The expressions of both SIRT1 and Beclin-1 as well as the ratio of LC3II/LC3I were significantly upregulated in the ALS mice, while melatonin reversed the upregulation of both SIRT1 and Beclin-1 expression and LC3II/LC3I ratio in a dose-dependent manner. In contrast, melatonin dose-dependently significantly restored the ALS-induced downregulation of p62. Furthermore, SIRT1 silencing notably reduced the effect of melatonin on Beclin-1, LC3II/LC3I, and p62. Melatonin induced autophagy in the ALS mice via the upregulation of SIRT1. Thus, melatonin might act as a new agent for the treatment of ALS.

Caffeic Acid Phenethyl Ester Attenuates Dextran Sulfate Sodium-Induced Ulcerative Colitis Through Modulation of NF-κB and Cell Adhesion Molecules

Ulcerative colitis (UC) is a serious health condition and defined as inflammation in the colon. Untreated, UC can develop into colitis-associated cancer (CAC), for which effective medicines are not available. Natural products are a better choice to treat UC by alleviating the inflammation. Caffeic acid phenethyl ester (CAPE) is a phenolic compound and known for its beneficial effects, including antibacterial, anti-inflammatory, anti-diabetic, and anticancer. We aimed to study the effect of CAPE on dextran sulfate sodium (DSS)-induced UC in mouse model. Administration of CAPE to DSS-induced mice protected against colon damage by improving body weight of mice, reducing the weight of spleen, and increased colon length. In addition, administration of CAPE resulted reduced the activity of myeloperoxidase (MPO) and CD68+ positive cells. Furthermore, a significant decrease in the production of key cytokines and the expression of nuclear factor (p65-NF)-κB. Moreover, p65-NF-κB activation was reduced in lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells from mouse origin. CAPE treatment leads to the reduced expressions of intercellular adhesion molecules (ICAM)-1 and vascular cell adhesion molecules (VCAM), both are key cell adhesion molecules. The results of this study clearly indicate that CAPE can potentially control inflammation in the colon and can be used as a therapy for UC.

Pharmacological Modulation of TRPM2 Channels via PARP Pathway Leads to Neuroprotection in MPTP-induced Parkinson's Disease in Sprague Dawley Rats

Transient receptor potential melastatin-2 (TRPM2) channels are cation channels activated by oxidative stress and ADP-ribose (ADPR). Role of TRPM2 channels has been postulated in several neurological disorders, but, it has not been explored in animal models of Parkinson's disease (PD). Thus, the role of TRPM2 and its associated poly (ADPR) polymerase (PARP) signaling pathways were investigated in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD rat model using TRPM2 inhibitor, 2-aminoethyl diphenyl borinate (2-APB), and PARP inhibitor, N-(6-Oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino) acetamide hydrochloride (PJ-34). PD was induced by using a bilateral intranigral administration of MPTP in rats, and different parameters were evaluated. An increase in oxidative stress was observed, leading to locomotor and cognitive deficits in the PD rats. PD rats also showed an increased TRPM2 expression in the striatum and mid-brain accompanied by reduced expression of tyrosine hydroxylase (TH) in comparison to sham animals. Intraperitoneal administration of 2-APB and PJ-34 led to an improvement in the locomotor and cognitive deficits in comparison to MPTP-induced PD rats. These improvements were accompanied by a reduction in the levels of oxidative stress and an increase in TH levels in the striatum and mid-brain. In addition, these pharmacological interventions also led to a decrease in the expression of TRPM2 in PD in the striatum and mid-brain. Our results provide a rationale for the development of potent pharmacological agents targeting the TRPM2-PARP pathway to provide therapeutic benefits for the treatment of neurological diseases like PD.

Protection against Amyloid-β Oligomer Neurotoxicity by Small Molecules with Antioxidative Properties: Potential for the Prevention of Alzheimer’s Disease Dementia

Soluble oligomeric assemblies of amyloid β-protein (Aβ), called Aβ oligomers (AβOs), have been recognized as primary pathogenetic factors in the molecular pathology of Alzheimer’s disease (AD). AβOs exert neurotoxicity and synaptotoxicity and play a critical role in the pathological progression of AD by aggravating oxidative and synaptic disturbances and tau abnormalities. As such, they are important therapeutic targets. From a therapeutic standpoint, it is not only important to clear AβOs or prevent their formation, it is also beneficial to reduce their neurotoxicity. In this regard, recent studies have reported that small molecules, most with antioxidative properties, show promise as therapeutic agents for reducing the neurotoxicity of AβOs. In this mini-review, we briefly review the significance of AβOs and oxidative stress in AD and summarize studies on small molecules with AβO-neurotoxicity-reducing effects. We also discuss mechanisms underlying the effects of these compounds against AβO neurotoxicity as well as their potential as drug candidates for the prevention and treatment of AD.