Presynaptic Release-Regulating Alpha2 Autoreceptors: Potential Molecular Target for Ellagic Acid Nutraceutical Properties

A Drug Discovery Approach to a Reveal Novel Antioxidant Natural Source: The Case of Chestnut Burr Biomass

Currently, many environmental and energy-related problems are threatening the future of our planet. In October 2022, the Worldmeter recorded the world population as 7.9 billion people, estimating that there will be an increase of 2 billion by 2057. The rapid growth of the population and the continuous increase in needs are causing worrying conditions, such as pollution, climate change, global warming, waste disposal, and natural resource reduction. Looking for novel and innovative methods to overcome these global troubles is a must for our common welfare. The circular bioeconomy represents a promising strategy to alleviate the current conditions using biomass-like natural wastes to replace commercial products that have a negative effect on our ecological footprint. Applying the circular bioeconomy concept, we propose an integrated in silico and in vitro approach to identify antioxidant bioactive compounds extracted from chestnut burrs (an agroforest waste) and their potential biological targets. Our study provides a novel and robust strategy developed within the circular bioeconomy concept aimed at target and drug discovery for a wide range of diseases. Our study could open new frontiers in the circular bioeconomy related to target and drug discovery, offering new ideas for sustainable scientific research aimed at identifying novel therapeutical strategies.

The Effects of Ellagic Acid on Experimental Corrosive Esophageal Burn Injury

This study aimed to investigate the antioxidant effect of Ellagic acid (EA) on wound healing in sodium hydroxide (NaOH)-induced corrosive esophageal burn injury. The interaction networks and functional annotations were conducted using Cytoscape software. A total of 24 Wistar albino rats were divided into control, corrosive esophageal burn (CEB) and CEB + EA groups. Burn injury was created by 20% NaOH and 30 mg/kg EA was per oral administered to rats. At the end of the 28-day experimental period, Malondialdehyde (MDA) content was measured. Esophageal tissue samples were processed for histological staining. The EA-target interaction network was revealed to be involved in regulating crucial cellular mechanisms for burn wound healing, with epidermal growth factor (EGF) identified as a central mediator. An increase in animal weight in the CEB + EA group was observed in the EA-treated group after CEB injury. Burn injury increased MDA content, but EA treatment decreased its level after CEB injury. Stenosis index, collagen degeneration, inflammation, fibrosis and necrosis levels were increased after CEB injury. EA treatment improved histopathology in the CEB + EA group compared to the CEB group. The expression of EGF was decreased in the CEB group but upregulated in the EA-treated group, suggesting a potential involvement of EA in cellular processes and tissue regeneration. EA, through its antioxidative and tissue regenerative properties, significantly contributes to alleviating the adverse effects of CEB injury, promoting wound healing.

Ellagic Acid Prevents α-Synuclein Spread and Mitigates Toxicity by Enhancing Autophagic Flux in an Animal Model of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurological disorder, pathologically characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) as well as the formation of Lewy bodies composed mainly of α-synuclein (α-syn) aggregates. It has been documented that abnormal aggregation of α-syn is one of the major causes of developing PD. In the current study, administration of ellagic acid (EA), a polyphenolic compound (10 mg/kg bodyweight), significantly decreased α-syn spreading and preserved dopaminergic neurons in a male C57BL/6 mouse model of PD. Moreover, EA altered the autophagic flux, suggesting the involvement of a restorative mechanism meditated by EA treatment. Our data support that EA could play a major role in the clearing of toxic α-syn from spreading, in addition to the canonical antioxidative role, and thus preventing dopaminergic neuronal death.

In Silico and In Vitro Study of Antioxidant Potential of Urolithins

In this work, quantum chemical calculations based on density functional theory (DFT) were performed to predict the antioxidant potential of four bioactive gut microbiota metabolites of the natural polyphenols ellagitannins (ETs) and ellagic acid (EA), also known as urolithins (UROs). In order to evaluate their ability to counter the effect of oxidative stress caused by reactive oxygen species (ROS), such as the hydroperoxyl radical (•OOH), different reaction mechanisms were investigated, considering water and lipid-like environments. Through our in silico results, it emerged that at physiological pH, the scavenging activity of all urolithins, except urolithin B, are higher than that of trolox and other potent antioxidants existing in nature, such as EA, α-mangostin, allicin, caffeine and melatonin. These findings were confirmed by experimental assays.

Activation of a novel α2AAR-spinophilin-cofilin axis determines the effect of α2 adrenergic drugs on fear memory reconsolidation

Posttraumatic stress disorder (PTSD) after the pandemic has emerged as a major neuropsychiatric component of post-acute COVID-19 syndrome, yet the current pharmacotherapy for PTSD is limited. The use of adrenergic drugs to treat PTSD has been suggested; however, it is hindered by conflicting clinical results and a lack of mechanistic understanding of drug actions. Our studies, using both genetically modified mice and human induced pluripotent stem cell-derived neurons, reveal a novel α2A adrenergic receptor (α2AAR)-spinophilin-cofilin axis in the hippocampus that is critical for regulation of contextual fear memory reconsolidation. In addition, we have found that two α2 ligands, clonidine and guanfacine, exhibit differential abilities in activating this signaling axis to disrupt fear memory reconsolidation. Stimulation of α2AAR with clonidine, but not guanfacine, promotes the interaction of the actin binding protein cofilin with the receptor and with the dendritic spine scaffolding protein spinophilin to induce cofilin activation at the synapse. Spinophilin-dependent regulation of cofilin is required for clonidine-induced disruption of contextual fear memory reconsolidation. Our results inform the interpretation of differential clinical observations of these two drugs on PTSD and suggest that clonidine could provide immediate treatment for PTSD symptoms related to the current pandemic. Furthermore, our study indicates that modulation of dendritic spine morphology may represent an effective strategy for the development of new pharmacotherapies for PTSD.

Guanfacine Normalizes the Overexpression of Presynaptic α-2A Adrenoceptor Signaling and Ameliorates Neuropathic Pain in a Chronic Animal Model of Type 1 Diabetes

Background: Diabetes is associated with several complications, including neuropathic pain, which is difficult to manage with currently available drugs. Descending noradrenergic neurons possess antinociceptive activity; however, their involvement in diabetic neuropathic pain remains to be explored. Methods: To infer the regulatory role of this system, we examined as a function of diabetes, the expression and localization of alpha-2A adrenoceptors (α2-AR) in the dorsal root ganglia and key regions of the central nervous system, including pons and lumbar segment of the spinal cord using qRT-PCR, Western blotting, and immunofluorescence-based techniques. Results: The data revealed that presynaptic synaptosomal-associated protein-25 labeled α2-AR in the central and peripheral nervous system of streptozotocin diabetic rats was upregulated both at the mRNA and protein levels. Interestingly, the levels of postsynaptic density protein-95 labeled postsynaptic neuronal α2-AR remained unaltered as a function of diabetes. These biochemical abnormalities in the noradrenergic system of diabetic animals were associated with increased pain sensitivity as typified by the presence of thermal hyperalgesia and cold/mechanical allodynia. The pain-related behaviors were assessed using Hargreaves apparatus, cold-plate and dynamic plantar aesthesiometer. Chronically administered guanfacine, a selective α2-AR agonist, to diabetic animals downregulated the upregulation of neuronal presynaptic α2-AR and ameliorated the hyperalgesia and the cold/mechanical allodynia in these animals. Conclusion: Together, these findings demonstrate that guanfacine may function as a potent analgesic and highlight α2-AR, a key component of the descending neuronal autoinhibitory pathway, as a potential therapeutic target in the treatment of diabetic neuropathic pain.

Chestnut Wood Mud as a Source of Ellagic Acid for Dermo-Cosmetic Applications

Ellagic acid (EA) has long been recognized as a very active antioxidant, anti-inflammatory, and antimicrobial agent. However, its low bioavailability has often hampered its applications in health-related fields. Here, we report a phospholipid vesicle-based controlled release system for EA, involving the exploitation of chestnut wood mud (CWM), an industrial by-product from chestnut tannin production, as a largely available and low-cost source of this compound. Two kinds of CWM with different particle size distributions, indicated as CWM-A and CWM-B (<100 and 32 µm, respectively), containing 5 ± 1% w/w EA, were incorporated into transfersomes. The latter were small in size (~100 nm), homogeneously dispersed, and negatively charged. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated up to three-fold improvement in the antioxidant properties of CWM upon incorporation into transfersomes. The kinetics of EA released under simulated physiological conditions were evaluated by UV-Vis spectroscopy and HPLC analysis. The best results were obtained with CWM-B (100% of EA gradually released after 37 days at pH 7.4). A stepwise increase in the antioxidant properties of the released material was also observed. Cell-based experiments confirmed the efficacy of CWM-B transfersomes as antioxidant agents in contrasting photodamage.