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

A comprehensive review of natural compounds and their structure-activity relationship in Parkinson's disease: exploring potential mechanisms

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopamine-producing cells in the Substantia nigra region of the brain. Complementary and alternative medicine approaches have been utilized as adjuncts to conventional therapies for managing the symptoms and progression of PD. Natural compounds have gained attention for their potential neuroprotective effects and ability to target various pathways involved in the pathogenesis of PD. This comprehensive review aims to provide an in-depth analysis of the molecular targets and mechanisms of natural compounds in various experimental models of PD. This review will also explore the structure-activity relationship (SAR) of these compounds and assess the clinical studies investigating the impact of these natural compounds on individuals with PD. The insights shared in this review have the potential to pave the way for the development of innovative therapeutic strategies and interventions for PD.

Injectable Hierarchical Bioactive Hydrogels with Fibroblast Growth Factor 21/Edaravone/Caffeic Acid Asynchronous Delivery for Treating Parkinson's Disease

Parkinson's disease (PD) is one of the most common long-term neurodegenerative disorders, with multiple comorbid psychiatric and behavioral abnormalities. The combination of clinical drugs targeting different symptoms with smart hydrogels to achieve asynchronous releases is highly translational and challenging. Here, a hierarchical bioactive hydrogel (OACDP) is designed with asynchronous release based on PD pathology. The hydrogel with caffeic acid-grafted polymer main chain is crosslinked using a micellar nanocrosslinker, with sufficient modulus (≈167 Pa), antioxidant activity (> 50%), injectability (30-gauge syringe needle), and shape-adaptability. Each of the three drugs (caffeic acid, fibroblast growth factor 21, and Edaravone) is separately engaged in different micro- or nanostructures of the hydrogel and released with asynchronous kinetics of first-order release, zero-order release, or matching Korsmeyer-Peppas model. The triple-loaded hydrogel is injected into the brains of PD rats, showing behavioral improvement. Histological analysis revealed that the triple-loaded OACDP hydrogels are effective in achieving immediate neuroprotection, i.e., reduction the loss of tyrosine hydroxylase in substantia nigra compacta and striatum (retained ≈10-fold versus control), decreasing oxidative stress, reducing astrocyte and microglia activation, and stimulating the AMPK/PGC-1α axis to regulate the mitochondrial function, providing a multi-dimensional PD therapy. The asynchronous release of OACDP hydrogel provides a new conception for PD treatment and other neurodegenerative diseases.

Combating Parkinson's disease with plant-derived polyphenols: Targeting oxidative stress and neuroinflammation

Parkinson's disease (PD) is a devastating neurodegenerative disorder predominantly affecting the elderly, characterized by the loss of dopaminergic neurons in the substantia nigra. Reactive oxygen species (ROS) generation plays a central role in the pathogenesis of PD and other neurodegenerative diseases. An imbalance between cellular antioxidant activity and ROS production leads to oxidative stress, contributing to disease progression. Dopamine metabolism, mitochondrial dysfunction, and neuroinflammation in dopaminergic neurons have been implicated in the pathogenesis of Parkinson's disease. Consequently, there is a pressing need for therapeutic interventions capable of scavenging ROS. Current pharmacological approaches, such as L-dihydroxyphenylalanine (levodopa or L-DOPA) and other drugs, provide symptomatic relief but are limited by severe side effects. Researchers worldwide have been exploring alternative compounds with less toxicity to address the multifaceted challenges associated with Parkinson's disease. In recent years, plant-derived polyphenolic compounds have gained significant attention as potential therapeutic agents. These compounds exhibit neuroprotective effects by targeting pathophysiological responses, including oxidative stress and neuroinflammation, in Parkinson's disease. The objective of this review is to summarize the current understanding of the neuroprotective effects of various polyphenols in Parkinson's disease, focusing on their antioxidant and anti-inflammatory properties, and to discuss their potential as therapeutic candidates. This review highlights the progress made in elucidating the molecular mechanisms of action of these polyphenols, identifying potential therapeutic targets, and optimizing their delivery and bioavailability. Well-designed clinical trials are necessary to establish the efficacy and safety of polyphenol-based interventions in the management of Parkinson's disease.

Medicinal herbal remedies in neurodegenerative diseases: an update on antioxidant potential

It has been widely documented that medicinal herbal remedies are effective, have fewer side effects than conventional medicine, and have a synergistic effect on health collaborations in the fight against complicated diseases. Traditional treatments for neurological problems in ancient times sometimes involved the use of herbal remedies and conventional methods from East Asian countries including India, Japan, China, and Korea. We collected and reviewed studies on plant-derived neuroprotective drugs and tested them in neurotoxic models. Basic research, preclinical and clinical transgene research can benefit from in silico, in vitro, and in vivo investigations. Research, summaries of the extracts, fractions, and herbal ingredients were compiled from popular scientific databases, which were then examined according to origin and bioactivity. Given the complex and varied causes of neurodegeneration, it may be beneficial to focus on multiple mechanisms of action and a neuroprotection approach. This approach aims to prevent cell death and restore function to damaged neurons, offering promising strategies for preventing and treating neurodegenerative diseases. Neurodegenerative illnesses can potentially be treated with natural compounds that have been identified as neuroprotective agents. To gain deeper insights into the neuropharmacological mechanisms underlying the neuroprotective and therapeutic properties of naturally occurring antioxidant phytochemical compounds in diverse neurodegenerative diseases, this study aims to comprehensively review such compounds, focusing on their modulation of apoptotic markers such as caspase, Bax, Bcl-2, and proinflammatory markers. In addition, we delve into a range of efficacies of antioxidant phytochemical compounds as neuroprotective agents in animal models. They reduce the oxidative stress of the brain and have been shown to have anti-apoptotic effects. Many researches have demonstrated that plant extracts or bioactive compounds can fight neurodegenerative disorders. Herbal medications may offer neurodegenerative disease patients' new treatments. This may be a cheaper and more culturally appropriate alternative to standard drugs for millions of people with age-related NDDs.

The anticancer impacts of free and liposomal caffeic acid phenethyl ester (CAPE) on melanoma cell line (A375)

The deadliest type of skin cancer, malignant melanoma, is also the reason for the majority of skin cancer-related deaths. The objective of this article was to investigate the efficiency of free caffeic acid phenethyl ester (CAPE) and liposomal CAPE in inducing apoptosis in melanoma cells (A375) in in vitro. CAPE was loaded into liposomes made up of hydrogenated soybean phosphatidylcholine, cholesterol, and 1,2-distearoyl-sn-glycero-3 phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000], and their physicochemical properties were assessed. (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test was performed for comparing the cytotoxicity of free CAPE and liposomal CAPE at dosages of 10, 15, 25, 50, 75 and the highest dose of 100 μg/mL for period of 24 and 48 h on A375 cell line to calculate IC50. Apoptosis and necrosis were evaluated in A375 melanoma cancer cells using flow cytometry. Atomic force microscopy was utilized to determine the nanomechanical attributes of the membrane structure of A375 cells. To determine whether there were any effects on apoptosis, the expression of PI3K/AKT1 and BAX/BCL2 genes was analyzed using the real-time polymerase chain reaction technique. According to our results, the maximum amount of drug release from nanoliposomes was determined to be 91% and the encapsulation efficiency of CAPE in liposomes was 85.24%. Also, the release of free CAPE was assessed to be 97%. Compared with liposomal CAPE, free CAPE showed a greater effect on reducing the cancer cell survival after 24 and 48 h. Therefore, IC50 values of A375 cells treated with free and liposomal CAPE were calculated as 47.34 and 63.39 μg/mL for 24 h. After 48 h of incubation of A375 cells with free and liposomal CAPE, IC50 values were determined as 30.55 and 44.83 μg/mL, respectively. The flow cytometry analysis revealed that the apoptosis induced in A375 cancer cells was greater when treated with free CAPE than when treated with liposomal CAPE. The highest nanomechanical changes in the amount of cell adhesion forces, and elastic modulus value were seen in free CAPE. Subsequently, the greatest decrease in PI3K/AKT1 gene expression ratio occurred in free CAPE.

The emerging role of breast cancer derived extracellular vesicles-mediated intercellular communication in ovarian cancer progression and metastasis

Breast cancer is one of the most occurring cancer types in women worldwide and metastasizes to several organs such as bone, lungs, liver, brain, and ovaries. Extracellular vesicles (EVs) mediate intercellular signaling which has a profound effect on tumor development and metastasis. Recent developments in the field of EVs provide an opportunity to investigate the roles of EVs released from tumor cells in metastasis. In this study, we compared the effects of metastatic breast cancer-derived EVs on both nonluteinized granulosa HGrC1 and ovarian cancer OVCAR-3 cells in terms of proliferation, invasion, apoptosis, and gene expression levels. EVs were isolated from the culture medium of metastatic breast cancer cell line MDA-MB-231 by ultracentrifugation. Cell proliferation, apoptosis, cell cycle, invasion, and cellular uptake analysis were performed to clarify the roles of tumor-derived EVs in both cells. 6.85 × 108 nanoparticles of BCD-EVs were markedly increased cell proliferation as well as invasion capacity. Exposing the cells with BCD-EVs for 24 h, resulted in an accumulation of both cells in G2/M phase as determined by flow cytometry. The apoptosis assay results were consistent with cell proliferation and cell cycle results. The uptake of the BCD-EVs was efficiently internalized by both cells. In addition, marked variations in fatty acid composition between cells were observed. BCD-EVs appeared new fatty acids in HGrC1. Besides, BCD-EVs upregulated epithelial-mesenchymal transition (EMT) and proliferation-related genes. In conclusion, an environment of tumor-derived EVs changes the cellular phenotype of cancer and noncancerous cells and may lead to tumor progression and metastasis.

Microencapsulation of Chilean Papaya Waste Extract and Its Impact on Physicochemical and Bioactive Properties

The microencapsulation of bioactive extracts of Chilean papaya waste, including both seeds and skin, was investigated. Papaya waste extract microcapsules utilizing maltodextrin at 10% (MD10), 20% (MD20), and 30% (MD30) (w/v) as the wall material through the freeze-drying process were obtained, and subsequently their physicochemical, antioxidant, and antimicrobial properties were evaluated. The TPC efficiency and yield values achieved were more than 60% for the microencapsulated seed and skin extracts, respectively. The best results for phenolic and antioxidant compounds were found in the microencapsulated seed extract with MD20, with a value of 44.20 ± 3.32 EAG/g DW for total phenols and an antioxidant capacity of 12.0 ± 0.32 mol ET/g DW for the DPPH and 236.3 ± 4.1 mol ET/g DW for the FRAP assay. In addition, the seed and skin samples reduced ROS generation in H2O2-treated Hek293 cells. In terms of antimicrobial activity, values ranging from 7 to 15 mm of inhibitory halos were found, with the maximum value corresponding to the inhibition of S. aureus, for both microencapsulated extracts. Therefore, the successful microencapsulation of the waste bioactive extracts (seed and skin) with the demonstrated antimicrobial and antioxidant properties highlight the bioactivity from Chilean papaya waste resources.

Therapeutic potential of endoplasmic reticulum stress inhibitors in the treatment of diabetic peripheral neuropathy

Endoplasmic stress response, the unfolded protein response (UPR), is a homeostatic signaling pathway comprising transmembrane sensors that get activated upon alterations in ER luminal environment. Studies suggest a relation between activated UPR pathways and several disease states such as Parkinson, Alzheimer, inflammatory bowel disease, tumor growth, and metabolic syndrome. Diabetic peripheral neuropathy (DPN), a common microvascular complication of diabetes-related chronic hyperglycemia, causes chronic pain, loss of sensation, foot ulcers, amputations, allodynia, hyperalgesia, paresthesia, and spontaneous pain. Factors like disrupted calcium signaling, dyslipidemia, hyperglycemia, inflammation, insulin signaling, and oxidative stress disturb the UPR sensor levels manifesting as DPN. We discuss new effective therapeutic alternatives for DPN that can be developed by targeting UPR pathways like synthetic ER stress inhibitors like 4-PhenylButyric acid (4-PBA), Sephin 1, Salubrinal and natural ER stress inhibitors like Tauroursodeoxycholic acid (TUDCA), Cordycepin, Proanthocyanidins, Crocin, Purple Rice extract and cyanidin and Caffeic Acid Phenethyl Ester (CAPE).

The Therapeutic Potential of Hydroxycinnamic Acid Derivatives in Parkinson's Disease: Focus on In Vivo Research Advancements

Hydroxycinnamic acid derivatives (HCDs) are polyphenols that are abundant in cereals, coffee, tea, wine, fruits, vegetables, and other plant-based foods. To aid in the clinical prevention and treatment of Parkinson's disease (PD), we evaluated in vivo investigations of the pharmacological properties of HCDs relevant to PD, and their pharmacokinetic and safety aspects. An extensive search of published journals was conducted using several literature databases, including PubMed, Google Scholar, and the Web of Science. The search terms included "hydroxycinnamic acid derivatives," "ferulic acid," "caffeic acid," "sinapic acid," "p-coumaric acid," "Parkinson's disease," and combinations of these keywords. As of April 2023, 455 preclinical studies were retrieved, of which 364 were in vivo studies; we included 17 of these articles on the pharmaceutics of HCDs in PD. Available evidence supports the protective effects of HCDs in PD due to their anti-inflammatory, antioxidant, as well as antiapoptotic physiological activities. Studies have identified possible molecular targets and pathways for the protective actions of HCDs in PD. However, the paucity of studies on these compounds in PD, and the risk of toxicity induced with high-dose applications, limits their use. Thus, multifaceted studies of HCDs in vitro and in vivo are needed.

Molecular understanding of the translational models and the therapeutic potential natural products of Parkinson's disease

Parkinson's disease is the second most prevalent neurodegenerative disease after Alzheimer's disease, mostly happened in the elder population and the prevalence gradually increased with age. Parkinson's disease is a movement disorder that severely affects patients' daily life. The mechanism of Parkinson's disease still remains unknown, however, studies already proved that the damage or absence of dopaminergic neurons located in the substantia nigra and the decreased dopamine in the striatum are significantly related to Parkinson's disease. To date, the mainstream treatment of Parkinson's disease has been achieved by alleviating its associated morbid symptoms, such as the use of levodopa, carbidopa, dopamine receptor agonists, monoamine oxidase type B inhibitors, anticholinergic drugs, etc. However, strong side effects, even toxicity, have been reported after using these drugs, with reduced effectiveness over time. Plant compounds have shown good therapeutic effects in neurodegenerative diseases as a less toxic treatment. In this review, we have compiled several natural plant compounds and classified the currently reported compounds for therapeutic use based on their structural parent nuclei and constituent elements. We wish to inspire new ideas for the treatment of Parkinson's disease by summarizing their mechanisms.

A Nano-Liposomal Formulation of Caffeic Acid Phenethyl Ester Modulates Nrf2 and NF-κβ Signaling and Alleviates Experimentally Induced Acute Pancreatitis in a Rat Model

The currently available management strategies for acute pancreatitis are inadequately effective which calls for exploration of new approaches to treat this condition. Caffeic acid phenethyl ester (CAPE) is a major bioactive constituent of honeybee propolis with promising therapeutic and preventive applications. However, its pharmaceutical potential and clinical use are hindered by its poor water solubility and limited plasma stability. In this study, we aimed to prepare, characterize and evaluate a CAPE-loaded nanoliposomal formulation to improve the efficacy of CAPE for the management of acute pancreatitis. The CAPE-loaded nanoliposomes (CAPE-loaded-NL) were prepared by a thin layer evaporation technique and were optimized using three edge activators. CAPE-loaded-NL were characterized for their vesicle size (VS), zeta potential (ZP), encapsulation efficiency (EE), polydispersity index (PDI), crystalline state and morphology. The protective effect of the optimal CAPE-loaded-NL was evaluated in a rat model of acute pancreatitis induced by administering a single intraperitoneal injection of L-ornithine. Oral pretreatment with CAPE-loaded-NL significantly counteracted ornithine-induced elevation in serum activities of pancreatic digestive enzymes and pancreatic levels of malondialdehyde, nuclear factor kappa B (NF-κB) p65, tumor necrosis factor-alpha, nitrite/nitrate, cleaved caspase-3 and myeloperoxidase activity. Moreover, pretreatment with CAPE-loaded-NL significantly reinstated the ornithine-lowered glutathione reductase activity, glutathione, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 levels and ATP/ADP ratio, and potentiated the Bcl-2/Bax ratio in pancreatic tissue. CAPE-loaded-NL displayed superior antioxidant, anti-inflammatory and anti-apoptotic effects compared to free CAPE oral suspension and achieved a more potent correction of the derangements in serum amylase and pancreatic myeloperoxidase activities. The histological observations were in line with the biochemical findings. Our results suggest that CAPE-loaded-NL provide a promising interventional approach for acute pancreatitis mainly through the enhancement of the exerted antioxidant, anti-inflammatory and anti-apoptotic effects which may be mediated, at least in part, through modulation of Nrf2 and NF-κβ signaling.

Differentiated pre-adipocytes promote proliferation, migration and epithelial-mesenchymal transition in breast cancer cells of different p53 status

Breast cancer progression and metastasis are associated with stromal cells in the tumor microenvironment. Adipocytes are the most abundant cells surrounding breast stromal tissue, promote tumor progression through the induction of Epithelial-to-Mesenchymal Transition (EMT) which is negatively regulated by tumor suppressor protein p53. In this study aimed to investigate the role of p53 in the progression of breast cancer after mature adipocyte-conditioned medium (CM) application. The proliferative effect of CM obtained from differentiated pre-adipocytes were assessed by MTS assay. 20% CM increased cell proliferation in breast cancer cells, T-47D (mutant p53) and MCF-7 (wild-type p53). The migration and invasion capacity were evaluated by scratch and transwell assays, respectively. CM significantly enhanced migration and invasion capacity in T-47D compared to MCF-7. Gene and protein expressions were detected by qRT-PCR and Western Blot analysis, respectively. CM markedly increased expression levels of Cyclin D1, PI3K, MMP9, Snail and Twist in T-47D compared to MCF-7. However, CM did not change E-Cadherin level in T-47D while downregulated in MCF-7 cells. Also, the protein levels of NFκB p65, p-Akt, Snail, and Vimentin were upregulated in both cells. Overall, the findings highlight how the p53 status affects mature adipocyte-mediated proliferation, migration, and aggressive behavior of breast cancer cell lines. Targeting the tumor microenvironment may represent a promising approach for preventing breast cancer progression and metastasis.

Natural Phytochemicals as Novel Therapeutic Strategies to Prevent and Treat Parkinson's Disease: Current Knowledge and Future Perspectives

Parkinson's disease (PD) is the second-most common neurodegenerative chronic disease affecting both cognitive performance and motor functions in aged people. Yet despite the prevalence of this disease, the current therapeutic options for the management of PD can only alleviate motor symptoms. Research has explored novel substances for naturally derived antioxidant phytochemicals with potential therapeutic benefits for PD patients through their neuroprotective mechanism, targeting oxidative stress, neuroinflammation, abnormal protein accumulation, mitochondrial dysfunction, endoplasmic reticulum stress, neurotrophic factor deficit, and apoptosis. The aim of the present study is to perform a comprehensive evaluation of naturally derived antioxidant phytochemicals with neuroprotective or therapeutic activities in PD, focusing on their neuropharmacological mechanisms, including modulation of antioxidant and anti-inflammatory activity, growth factor induction, neurotransmitter activity, direct regulation of mitochondrial apoptotic machinery, prevention of protein aggregation via modulation of protein folding, modification of cell signaling pathways, enhanced systemic immunity, autophagy, and proteasome activity. In addition, we provide data showing the relationship between nuclear factor E2-related factor 2 (Nrf2) and PD is supported by studies demonstrating that antiparkinsonian phytochemicals can activate the Nrf2/antioxidant response element (ARE) signaling pathway and Nrf2-dependent protein expression, preventing cellular oxidative damage and PD. Furthermore, we explore several experimental models that evaluated the potential neuroprotective efficacy of antioxidant phytochemical derivatives for their inhibitory effects on oxidative stress and neuroinflammation in the brain. Finally, we highlight recent developments in the nanodelivery of antioxidant phytochemicals and its neuroprotective application against pathological conditions associated with oxidative stress. In conclusion, naturally derived antioxidant phytochemicals can be considered as future pharmaceutical drug candidates to potentially alleviate symptoms or slow the progression of PD. However, further well-designed clinical studies are required to evaluate the protective and therapeutic benefits of phytochemicals as promising drugs in the management of PD.

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.

Neuroprotective Effects of Methyl Caffeate against Hydrogen Peroxide-Induced Cell Damage: Involvement of Caspase 3 and Cathepsin D Inhibition

Finding effective neuroprotective strategies to combat various neurodegenerative disorders still remain a clinically unmet need. Methyl caffeate (MC), a naturally occurring ester of caffeic acid, possesses antioxidant and anti-inflammatory activities; however, its role in neuroprotection is less investigated. In order to better characterize neuroprotective properties of MC, we tested its effectiveness in various models of neuronal cell injury in human neuroblastoma SH-SY5Y cells and in mouse primary neuronal cell cultures. MC at micromolar concentrations attenuated neuronal cell damage induced by hydrogen peroxide (H2O2) in undifferentiated and neuronal differentiated SH-SY5Y cells as well as in primary cortical neurons. This effect was associated with inhibition of both caspase-3 and cathepsin D but without involvement of the PI3-K/Akt pathway. MC was neuroprotective when given before and during but not after the induction of cell damage by H2O2. Moreover, MC was protective against 6-OHDA-evoked neurotoxicity in neuronal differentiated SH-SY5Y cells via inhibition of necrotic and apoptotic processes. On the other hand, MC was ineffective in models of excitotoxicity (induced by glutamate or oxygen-glucose deprivation) and even moderately augmented cytotoxic effects of the classical apoptotic inducer, staurosporine. Finally, in undifferentiated neuroblastoma cells MC at higher concentrations (above 50 microM) induced cell death and when combined with the chemotherapeutic agent, doxorubicin, it increased the cell damaging effects of the latter compound. Thus, neuroprotective properties of MC appear to be limited to certain models of neurotoxicity and depend on its concentrations and time of administration.