Redox Modulation of Meniere Disease by Coriolus Versicolor Treatment, a Nutritional Mushroom Approach with Neuroprotective Potential.

BACKGROUND: Meniere's disease (MD) is a cochlear neurodegenerative disease. Hearing loss appears to be triggered by oxidative stress in the ganglion neurons of the inner ear. OBJECTIVE: Here, we confirm the variation of markers of oxidative stress and inflammation in patients with Meniere and hypothesize that chronic treatment with Coriolus mushroom helps in the response to oxidative stress and acts on α-synuclein and on NF-kB-mediated inflammatory processes. METHODS: Markers of oxidative stress and inflammation were evaluated in MD patients with or without Coriolus treatment for 3 or 6 months. RESULTS: MD patients had a small increase in Nrf2, HO-1, γ-GC, Hsp70, Trx and sirtuin-1, which were further increased by Coriolus treatment, especially after 6 months. Increased markers of oxidative damage, such as protein carbonyls, HNE, and ultraweak chemiluminescence, associated with a decrease in plasma GSH/GSSG ratio, were also observed in lymphocytes from MD patients. These parameters were restored to values similar to the baseline in patients treated with Coriolus for both 3 and 6 months. Furthermore, treated MD subjects showed decreased expression of α-synuclein, GFAP and Iba-1 proteins and modulation of the NF-kB pathway, which were impaired in MD patients. These changes were greatest in subjects taking the supplements for 6 months. CONCLUSIONS: Our study suggests MD as a model of cochlear neurodegenerative disease for the identification of potent inducers of the Nrf2-vitagene pathway, able to reduce the deleterious consequences associated with neurodegenerative damage, probably by indirectly acting on α-synuclein expression and on inflammatory processes NF- kB-mediated.

Polyphenols in Inner Ear Neurobiology, Health and Disease: From Bench to Clinics.

There is substantial experimental and clinical interest in providing effective ways to both prevent and slow the onset of hearing loss. Auditory hair cells, which occur along the basilar membrane of the cochlea, often lose functionality due to age-related biological alterations, as well as from exposure to high decibel sounds affecting a diminished/damaged auditory sensitivity. Hearing loss is also seen to take place due to neuronal degeneration before or following hair cell destruction/loss. A strategy is necessary to protect hair cells and XIII cranial/auditory nerve cells prior to injury and throughout aging. Within this context, it was proposed that cochlea neural stem cells may be protected from such aging and environmental/noise insults via the ingestion of protective dietary supplements. Of particular importance is that these studies typically display a hormetic-like biphasic dose-response pattern that prevents the occurrence of auditory cell damage induced by various model chemical toxins, such as cisplatin. Likewise, the hormetic dose-response also enhances the occurrence of cochlear neural cell viability, proliferation, and differentiation. These findings are particularly important since they confirmed a strong dose dependency of the significant beneficial effects (which is biphasic), whilst having a low-dose beneficial response, whereas extensive exposures may become ineffective and/or potentially harmful. According to hormesis, phytochemicals including polyphenols exhibit biphasic dose-response effects activating low-dose antioxidant signaling pathways, resulting in the upregulation of vitagenes, a group of genes involved in preserving cellular homeostasis during stressful conditions. Modulation of the vitagene network through polyphenols increases cellular resilience mechanisms, thus impacting neurological disorder pathophysiology. Here, we aimed to explore polyphenols targeting the NF-E2-related factor 2 (Nrf2) pathway to neuroprotective and therapeutic strategies that can potentially reduce oxidative stress and inflammation, thus preventing auditory hair cell and XIII cranial/auditory nerve cell degeneration. Furthermore, we explored techniques to enhance their bioavailability and efficacy.

Polyamines and hormesis: Making sense of a dose response dichotomy.

The diverse biological effects of polyamines (putrescine, spermidine and spermine) were reviewed in the context of hormesis in an integrative manner for the first time. The findings illustrate that each of these polyamines commonly induces hormetic dose responses in a wide range of biological models and types of cells for multiple endpoints in numerous plant species and animal models. Plant research emphasized preconditioning experimental studies in which the respective polyamines conferred some protection against the damaging effects of a broad range of environmental stressors such as drought, salinity, cold/heat, heavy metals and UV-damage in an hormetic manner. Polyamine-based animal hormesis studies emphasized biomedical endpoints such as longevity and neuroprotection. These findings have important biological and biomedical implications and should guide experimental designs of low dose investigations.

Moringa induces its beneficial effect via hormesis.

Moringa oleifera, a traditional Indian herb, is widely known for its capacity to induce antioxidant, anti-inflammatory and other chemoprotective effects in a broad range of biomedical models. These perspectives have led to an extensive number of studies using various moringa extracts to evaluate its capacity to protect biological systems from oxidative stress and to explore whether it could be used to slow the onset of numerous age-related conditions and diseases. Moringa extracts have also been applied to prevent damage to plants from oxidative and saline stresses, following hormetic dose­response patterns. The present paper provides the first integrated and mechanistically based assessment showing that moringa extracts commonly induce hormetic dose responses and that many, perhaps most, of the beneficial effects of moringa are due to its capacity to act as an hormetic agent.

Antioxidants, Hormetic Nutrition, and Autism.

Autism spectrum disorder (ASD) includes a heterogeneous group of complex neurodevel opmental disorders characterized by atypical behaviors with two core pathological manifestations: deficits in social interaction/communication and repetitive behaviors, which are associated with disturbed redox homeostasis. Modulation of cellular resilience mechanisms induced by low levels of stressors represents a novel approach for the development of therapeutic strategies, and in this context, neuroprotective effects of a wide range of polyphenol compounds have been demonstrated in several in vitro and in vivo studies and thoroughly reviewed by [2, 3]. Mushrooms have been used in traditional medicine for many years and have been associated with a long list of therapeutic properties, including antitumor, immunomodulatory, antioxidant, antiviral, antibacterial, and hepatoprotective effects [4]. Our recent studies have strikingly indicated the presence of polyphenols in nutritional mushrooms and demonstrated their protective effects in different models of neurodegenerative disorders in humans and rats [5, 6]. Although their therapeutic effects are exerted through multiple mechanisms, increasing attention is focusing on their capacity to induce endogenous defense systems by modulating cellular signaling processes, such as nuclear factor erythroid 2 related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB) pathways. Here we discuss the protective role of hormesis and its modulation by hormetic nutrients in ASD.

Rhodiola rosea and salidroside commonly induce hormesis, with particular focus on longevity and neuroprotection.

The biological effects of Rhodiola rosea extracts and one of its major constituents, salidroside, were evaluated for their capacity to induce hormesis/hormetic effects. The findings indicate that the Rhodiola rosea extracts and salidroside commonly induce hormetic dose responses within a broad range of biological models, cell types and across a broad range of endpoints, with particular emphasis on longevity and neuroprotective endpoints. This paper represents the first integrative documentation and assessment of Rhodiola rosea extracts and salidroside induction of hormetic effects. These findings have important biomedical applications and should have an important impact with respect to critical study design, dose selection and other experimental features.

Protective effects of alpha lipoic acid (ALA) are mediated by hormetic mechanisms.

The endogenous and dietary agent, alpha lipoic acid (ALA), is evaluated for its capacity to induce a broad spectrum of adaptive responses via hormetic dose responses and their underlying mechanisms. ALA was shown to induce hormetic effects in a wide range of experimental models within in vitro and in vivo experimental settings which included direct exposure and pre- and post-conditioning experimental protocols. The hormetic effects occur in a broad range of organ systems, including the brain, heart, kidney and other tissues, with possible public health and clinical/therapeutic applications linked to reducing the onset and progression of neurogenerative diseases and also in the preservation of sperm health and functionality during cryopreservation. This paper provides the first integrated assessment of ALA-induced hormetic dose responses. Underlying mechanisms that mediated the occurrence of ALA-induced hormetic effects involved the induction of low levels of ROS that activate key cell signaling antioxidant (e.g. Nrf2) pathways.

Hormesis: wound healing and fibroblasts.

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Association Between Beta-Carotene Supplementation and Mortality: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: Aging is a phenomenon universally involving all organisms, genetically determined, and epigenetically influenced by the environment. Numerous observational studies have shown the positive impact of non-pharmacological approaches started in younger age on chronic conditions affecting the elderly health and survival. This meta-analysis aimed to investigate the effect of beta-carotene on the total and cause-specific mortality as reported by randomized controlled trials (RCTs). Methods: We searched Medline, Scopus, Web of Science, and CENTRAL Cochrane from inception to September 2021. Studies were eligible if enrolled adults with any health condition, compared beta-carotene supplements at any dose with placebo or no intervention, provided information on deaths from any cause, and were RCTs, in English. The risk of bias was assessed by the Cochrane risk of bias tool and the GRADE. Risk ratios and their 95% confidence intervals were used and a P-value less than 0.05 was considered statistically significant. Results: Among 3,942 articles searched, 44 articles on 31 RCTs, which included 216,734 total subjects, 108,622 in beta-carotene supplement groups, and 108,112 in the placebo or no-intervention groups, were involved in the final analyses. In a random-effects meta-analysis of all 31 trials, beta-carotene supplements were found to have no preventive effect on mortality (risk ratio 1.02, 95% confidence interval 0.98-1.05, I 2 = 42%). Further, the analysis showed no preventive effect on cancer, cardiovascular, cerebrovascular, and other mortality causes. Instead, beta-carotene supplementation significantly increased the risk of lung cancer mortality (RR 1.14, 95% CI 1.02, 1.27, I 2 = 3%) but decreased the risk of human immunodeficiency virus-related mortality (RR 0.55, 95% CI 0.33, 0.92, I 2 = 0). Conclusion: More studies should be performed to better define the role of beta-carotene on survival, to confirm or deny our results. Therefore, the possible beneficial or harmful effects of the beta-carotene supplementation on mortality must not be overstated. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=259354], identifier [CRD42021259354].

Enhancing health span: muscle stem cells and hormesis.

Sarcopenia is a significant public health and medical concern confronting the elderly. Considerable research is being directed to identify ways in which the onset and severity of sarcopenia may be delayed/minimized. This paper provides a detailed identification and assessment of hormetic dose responses in animal model muscle stem cells, with particular emphasis on cell proliferation, differentiation, and enhancing resilience to inflammatory stresses and how this information may be useful in preventing sarcopenia. Hormetic dose responses were observed following administration of a broad range of agents, including dietary supplements (e.g., resveratrol), pharmaceuticals (e.g., dexamethasone), endogenous ligands (e.g., tumor necrosis factor α), environmental contaminants (e.g., cadmium) and physical agents (e.g., low level laser). The paper assesses both putative mechanisms of hormetic responses in muscle stem cells, and potential therapeutic implications and application(s) of hormetic frameworks for slowing muscle loss and reduced functionality during the aging process.

Human dental pulp stem cells and hormesis.

This paper represents the first assessment of hormetic dose responses by human dental pulp stem cells (hDPSCs) with particular emphasis on cell renewal (proliferation) and differentiation. Hormetic dose responses were commonly reported in this model, encompassing a broad range of chemicals, including principally pharmaceuticals (e.g., metformin and artemisinin), dietary supplements/extracts from medicinal plants (e.g., berberine, N-acetyl-L-cysteine, and ginsenoside Rg1) and endogenous agents (e.g., ATP, TNF-α). The paper assesses mechanistic foundations of the hDPSCs hormetic dose responses for both cell proliferation and cell differentiation, study design considerations, and therapeutic implications.

Redox modulation by plant polyphenols targeting vitagenes for chemoprevention and therapy: Relevance to novel anti-cancer interventions and mini-brain organoid technology.

The scientific community, recently, has focused notable attention on the chemopreventive and therapeutic effects of dietary polyphenols for human health. Emerging evidence demonstrates that polyphenols, flavonoids and vitamins counteract and neutralize genetic and environmental stressors, particularly oxidative stress and inflammatory process closely connected to cancer initiation, promotion and progression. Interestingly, polyphenols can exert antioxidant or pro-oxidant cytotoxic effects depending on their endogenous concentration. Notably, polyphenols at high dose act as pro-oxidants in a wide type of cancer cells by inhibiting Nrf2 pathway and the expression of antioxidant vitagenes, such as NAD(P)H-quinone oxidoreductase (NQO1), glutathione transferase (GT), GPx, heme oxygenase-1 (HO-1), sirtuin-1 (Sirt1) and thioredoxin (Trx) system which play an essential role in the metabolism of reactive oxygen species (ROS), detoxification of xenobiotics and inhibition of cancer progression, by inducing apoptosis and cell cycle arrest according to the hormesis approach. Importantly, mutagenesis of Nrf2 pathway can exacerbate its "dark side" role, representing a crucial event in the initiation stage of carcinogenesis. Herein, we review the hormetic effects of polyphenols and nanoincapsulated-polyphenols in chemoprevention and treatment of brain tumors via activation or inhibition of Nrf2/vitagenes to suppress carcinogenesis in the early stages, and thus inhibit its progression. Lastly, we discuss innovative preclinical approaches through mini-brain tumor organoids to study human carcinogenesis, from basic cancer research to clinical practice, as promising tools to recapitulate the arrangement of structural neuronal tissues and biological functions of the human brain, as well as test drug toxicity and drive personalized and precision medicine in brain cancer.

Hormesis and neural stem cells.

This paper provides a detailed identification and assessment of hormetic dose responses in neural stem cells (NSCs) as identified in a number of animal models and human tissues, with particular emphasis on cell proliferation and differentiation. Hormetic dose responses were commonly observed following administration of a number of agents, including dietary supplements [e.g., berberine, curcumin, (-)-epigallocatechin-3-gallate (EGCG), Ginkgo Biloba, resveratrol], pharmaceuticals (e.g., lithium, lovastatin, melatonin), endogenous ligands [e.g., hydrogen sulfide (H2S), magnesium, progesterone, taurine], environmental contaminants (e.g., arsenic, rotenone) and physical agents [e.g., hypoxia, ionizing radiation, electromagnetic radiation (EMF)]. These data indicate that numerous agents can induce hormetic dose responses to upregulate key functions of such as cell proliferation and differentiation in NSCs, and enhance resilience to inflammatory stresses. The paper assesses both putative mechanisms of hormetic responses in NSCs, and the potential therapeutic implications and application(s) of hormetic frameworks in clinical approaches to neurological injury and disease.

Redox modulation of vitagenes via plant polyphenols and vitamin D: Novel insights for chemoprevention and therapeutic interventions based on organoid technology.

Polyphenols are chemopreventive through the induction of nuclear factor erythroid 2 related factor 2 (Nrf2)-mediated proteins and anti-inflammatory pathways. These pathways, encoding cytoprotective vitagenes, include heat shock proteins, such as heat shock protein 70 (Hsp70) and heme oxygenase-1 (HO-1), as well as glutathione redox system to protect against cancer initiation and progression. Phytochemicals exhibit biphasic dose responses on cancer cells, activating at low dose, signaling pathways resulting in upregulation of vitagenes, as in the case of the Nrf2 pathway upregulated by hydroxytyrosol (HT) or curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Here, the importance of vitagenes in redox stress response and autophagy mechanisms, as well as the potential use of dietary antioxidants in the prevention and treatment of multiple types of cancer are discussed. We also discuss the possible relationship between SARS-CoV-2, inflammation and cancer, exploiting innovative therapeutic approaches with HT-rich aqueous olive pulp extract (Hidrox®), a natural polyphenolic formulation, as well as the rationale of Vitamin D supplementation. Finally, we describe innovative approaches with organoids technology to study human carcinogenesis in preclinical models from basic cancer research to clinical practice, suggesting patient-derived organoids as an innovative tool to test drug toxicity and drive personalized therapy.

Moringa oleifera Protects SH-SY5YCells from DEHP-Induced Endoplasmic Reticulum Stress and Apoptosis.

Moringa oleifera (MO) is a medicinal plant that has been shown to possess antioxidant, anticarcinogenic and antibiotic activities. In a rat model, MO extract (MOe) has been shown to have a protective effect against brain damage and memory decline. As an extending study, here, we have examined the protective effect of MOe against oxidative stress and apoptosis caused in human neuroblastome (SH-SY5Y) cells by di-(2-ethylhexyl) phthalate (DEHP), a plasticizer known to induce neurotoxicity. Our data show that MOe prevents oxidative damage by lowering reactive oxygen species (ROS) formation, restoring mitochondrial respiratory chain complex activities, and, in addition, by modulating the expression of vitagenes, i.e., antioxidant proteins Nrf2 and HO-1. Moreover, MOe prevented neuronal damage by partly inhibiting endoplasmic reticulum (ER) stress response, as indicated by decreased expression of CCAAT-enhancer-binding protein homologous protein (CHOP) and Glucose-regulated protein 78 (GRP78) proteins. MOe also protected SH-SY5Y cells from DEHP-induced apoptosis, preserving mitochondrial membrane permeability and caspase-3 activation. Our findings provide insight into understanding of molecular mechanisms involved in neuroprotective effects by MOe against DEHP damage.

Hericium Erinaceus Prevents DEHP-Induced Mitochondrial Dysfunction and Apoptosis in PC12 Cells.

Hericium Erinaceus (HE) is a medicinal plant known to possess anticarcinogenic, antibiotic, and antioxidant activities. It has been shown to have a protective effect against ischemia-injury-induced neuronal cell death in rats. As an extending study, here we examined in pheochromocytoma 12 (PC12) cells, whether HE could exert a protective effect against oxidative stress and apoptosis induced by di(2-ethylhexyl)phthalate (DEHP), a plasticizer known to cause neurotoxicity. We demonstrated that pretreatment with HE significantly attenuated DEHP induced cell death. This protective effect may be attributed to its ability to reduce intracellular reactive oxygen species levels, preserving the activity of respiratory complexes and stabilizing the mitochondrial membrane potential. Additionally, HE pretreatment significantly modulated Nrf2 and Nrf2-dependent vitagenes expression, preventing the increase of pro-apoptotic and the decrease of anti-apoptotic markers. Collectively, our data provide evidence of new preventive nutritional strategy using HE against DEHP-induced apoptosis in PC12 cells.

Healthy Effects of Plant Polyphenols: Molecular Mechanisms.

The increasing extension in life expectancy of human beings in developed countries is accompanied by a progressively greater rate of degenerative diseases associated with lifestyle and aging, most of which are still waiting for effective, not merely symptomatic, therapies. Accordingly, at present, the recommendations aimed at reducing the prevalence of these conditions in the population are limited to a safer lifestyle including physical/mental exercise, a reduced caloric intake, and a proper diet in a convivial environment. The claimed health benefits of the Mediterranean and Asian diets have been confirmed in many clinical trials and epidemiological surveys. These diets are characterized by several features, including low meat consumption, the intake of oils instead of fats as lipid sources, moderate amounts of red wine, and significant amounts of fresh fruit and vegetables. In particular, the latter have attracted popular and scientific attention for their content, though in reduced amounts, of a number of molecules increasingly investigated for their healthy properties. Among the latter, plant polyphenols have raised remarkable interest in the scientific community; in fact, several clinical trials have confirmed that many health benefits of the Mediterranean/Asian diets can be traced back to the presence of significant amounts of these molecules, even though, in some cases, contradictory results have been reported, which highlights the need for further investigation. In light of the results of these trials, recent research has sought to provide information on the biochemical, molecular, epigenetic, and cell biology modifications by plant polyphenols in cell, organismal, animal, and human models of cancer, metabolic, and neurodegenerative pathologies, notably Alzheimer's and Parkinson disease. The findings reported in the last decade are starting to help to decipher the complex relations between plant polyphenols and cell homeostatic systems including metabolic and redox equilibrium, proteostasis, and the inflammatory response, establishing an increasingly solid molecular basis for the healthy effects of these molecules. Taken together, the data currently available, though still incomplete, are providing a rationale for the possible use of natural polyphenols, or their molecular scaffolds, as nutraceuticals to contrast aging and to combat many associated pathologies.

Hormesis and Ginkgo biloba (GB): Numerous biological effects of GB are mediated via hormesis.

Ginkgo biloba (GB) extracts have been shown to commonly induce biphasic dose responses in a range of cell types and endpoints (e.g., cochlea neural stem cells, cell viability, cell proliferation). The magnitude and width of the low dose stimulation of these biphasic dose responses are similar to those reported for hormetic dose responses. These hormetic dose responses occur within direct stimulatory responses as well as in preconditioning experimental protocols, displaying acquired resistance within an adaptive homeodynamic and temporal framework and repeated measurement protocols. The demonstrated GB dose responses further reflect the general occurrence of hormetic dose responses that consistently appear to be independent of the biological model, endpoint, inducing agent, and/or mechanism. These findings have important implications for consideration(s) of study designs involving dose selection, dose spacing, sample size, and statistical power. This illustrates and strengthens the need to characterize the low dose stimulatory response range and optimal dose in order to explore potential public health and clinical applications of plant-derived agents, such as GB.

Nutritional Mushroom Treatment in Meniere's Disease with Coriolus versicolor: A Rationale for Therapeutic Intervention in Neuroinflammation and Antineurodegeneration.

Meniere's disease (MD) represents a clinical syndrome characterized by episodes of spontaneous vertigo, associated with fluctuating, low to medium frequencies sensorineural hearing loss (SNHL), tinnitus, and aural fullness affecting one or both ears. To date, the cause of MD remains substantially unknown, despite increasing evidence suggesting that oxidative stress and neuroinflammation may be central to the development of endolymphatic hydrops and consequent otholitic degeneration and displacement in the reuniting duct, thus originating the otolithic crisis from vestibular otolithic organs utricle or saccule. As a starting point to withstand pathological consequences, cellular pathways conferring protection against oxidative stress, such as vitagenes, are also induced, but at a level not sufficient to prevent full neuroprotection, which can be reinforced by exogenous nutritional approaches. One emerging strategy is supplementation with mushrooms. Mushroom preparations, used in traditional medicine for thousands of years, are endowed with various biological actions, including antioxidant, immunostimulatory, hepatoprotective, anticancer, as well as antiviral effects. For example, therapeutic polysaccharopeptides obtained from Coriolus versicolor are commercially well established. In this study, we examined the hypothesis that neurotoxic insult represents a critical primary mediator operating in MD pathogenesis, reflected by quantitative increases of markers of oxidative stress and cellular stress response in the peripheral blood of MD patients. We evaluated systemic oxidative stress and cellular stress response in MD patients in the absence and in the presence of treatment with a biomass preparation from Coriolus. Systemic oxidative stress was estimated by measuring, in plasma, protein carbonyls, hydroxynonenals (HNE), and ultraweak luminescence, as well as by lipidomics analysis of active biolipids, such as lipoxin A4 and F2-isoprostanes, whereas in lymphocytes we determined heat shock proteins 70 (Hsp72), heme oxygenase-1 (HO-1), thioredoxin (Trx), and γ-GC liase to evaluate the systemic cellular stress response. Increased levels of carbonyls, HNE, luminescence, and F2-isoprostanes were found in MD patients with respect to the MD plus Coriolus-treated group. This was paralleled by a significant (p < 0.01) induction, after Coriolus treatment, of vitagenes such as HO-1, Hsp70, Trx, sirtuin-1, and γ-GC liase in lymphocyte and by a significant (p < 0.05) increase in the plasma ratio-reduced glutathione (GSH) vs. oxidized glutathione (GSSG). In conclusion, patients affected by MD are under conditions of systemic oxidative stress, and the induction of vitagenes after mushroom supplementation indicates a maintained response to counteract intracellular pro-oxidant status. The present study also highlights the importance of investigating MD as a convenient model of cochlear neurodegenerative disease. Thus, searching innovative and more potent inducers of the vitagene system can allow the development of pharmacological strategies capable of enhancing the intrinsic reserve of vulnerable neurons, such as ganglion cells to maximize antidegenerative stress responses and thus providing neuroprotection.

Melaleuca styphelioides Sm. Polyphenols Modulate Interferon Gamma/Histamine-Induced Inflammation in Human NCTC 2544 Keratinocytes.

Melaleuca styphelioides, known as the prickly-leaf tea tree, contains a variety of bioactive compounds. The purposes of this study were to characterize the polyphenols extracted from Melaleuca styphelioides leaves and assess their potential antioxidant and anti-inflammatory effects. The polyphenol extracts were prepared by maceration with solvents of increasing polarity. The LC/MS-MS technique was used to identify and quantify the phenolic compounds. An assessment of the radical scavenging activity of all extracts was performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS⁺), and ferric reducing antioxidant power (FRAP) assays. The anti-inflammatory activity was determined on interferon gamma (IFN-γ)/histamine (H)-stimulated human NCTC 2544 keratinocytes by Western blot and RT-PCR. Compared to other solvents, methanolic extract presented the highest level of phenolic contents. The most frequent phenolic compounds were quercetin, followed by gallic acid and ellagic acid. DPPH, ABTS⁺, and FRAP assays showed that methanolic extract exhibits strong concentration-dependent antioxidant activity. IFN-γ/H treatment of human NCTC 2544 keratinocytes induced the secretion of high levels of the pro-inflammatory mediator inter-cellular adhesion molecule-1 (ICAM-1), nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor kappa B (NF-κB), which were inhibited by extract. In conclusion, the extract of Melaleuca styphelioides leaves is rich in flavonoids, and presents antioxidant and anti-inflammatory proprieties. It can be proposed as a useful compound to treat inflammatory skin diseases.