Hydroxytyrosol attenuates diquat-induced oxidative stress by activating Nrf2 pathway and modulating colonic microbiota in mice

The role of Nrf2 signaling pathways in nerve damage repair

The protein, Nuclear factor-E2-related factor 2 (Nrf2), is a transitory protein that acts as a transcription factor and is involved in the regulation of many cytoprotective genes linked to xenobiotic metabolism and antioxidant responses. Based on the existing clinical and experimental data, it can be inferred that neurodegenerative diseases are characterized by an excessive presence of markers of oxidative stress (OS) and a reduced presence of antioxidant defense systems in both the brain and peripheral tissues. The presence of imbalances in the homeostasis between oxidants and antioxidants has been recognized as a substantial factor in the pathogenesis of neurodegenerative disorders. The dysregulations include several cellular processes such as mitochondrial failure, protein misfolding, and neuroinflammation. These dysregulations all contribute to the disruption of proteostasis in neuronal cells, leading to their eventual mortality. A noteworthy component of Nrf2, as shown by recent research undertaken over the last decade, is to its role in the development of resistance to OS. Nrf2 plays a pivotal role in regulating systems that defend against OS. Extant research offers substantiation for the protective and defensive roles of Nrf2 in the context of neurodegenerative diseases. The purpose of this study is to provide a comprehensive analysis of the influence of Nrf2 on OS and its function in regulating antioxidant defense systems within the realm of neurodegenerative diseases. Furthermore, we evaluate the most recent academic inquiries and empirical evidence about the beneficial and potential role of certain Nrf2 activator compounds within the realm of therapeutic interventions.

Hydroxytyrosol Alleviates Intestinal Oxidative Stress by Regulating Bile Acid Metabolism in a Piglet Model

Infants and young animals often suffer from intestinal damage caused by oxidative stress, which may adversely affect their overall health. Hydroxytyrosol, a plant polyphenol, has shown potential in decreasing intestinal oxidative stress, but its application and mechanism of action in infants and young animals are still inadequately documented. This study selected piglets as a model to investigate the alleviating effects of hydroxytyrosol on intestinal oxidative stress induced by diquat and its potential mechanism. Hydroxytyrosol improved intestinal morphology, characterized by higher villus height and villus height/crypt depth. Meanwhile, hydroxytyrosol led to higher expression of Occludin, MUC2, Nrf2, and its downstream genes, and lower expression of cytokines IL-1β, IL-6, and TNF-α. Both oxidative stress and hydroxytyrosol resulted in a higher abundance of Clostridium_sensu_stricto_1, and a lower abundance of Lactobacillus and Streptococcus, without a significant effect on short-chain fatty acids levels. Oxidative stress also led to disorders in bile acid (BA) metabolism, such as the lower levels of primary BAs, hyocholic acid, hyodeoxycholic acid, and tauroursodeoxycholic acid, which were partially restored by hydroxytyrosol. Correlation analysis revealed a positive correlation between these BA levels and the expression of Nrf2 and its downstream genes. Collectively, hydroxytyrosol may reduce oxidative stress-induced intestinal damage by regulating BA metabolism.

Unlocking the effective alliance of β-lapachone and hydroxytyrosol against triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is characterised by its aggressiveness and resistance to chemotherapy, demanding the development of effective strategies against its unique characteristics. Derived from lapacho tree bark, β-lapachone (β-LP) selectively targets cancer cells with elevated levels of the detoxifying enzyme NQO1. Hydroxytyrosol (HT) is a phenolic compound derived from olive trees with important anticancer properties that include the inhibition of cancer stem cells (CSCs) and metastatic features in TNBC, as well as relevant antioxidant activities by mechanisms such as the induction of NQO1. We aimed to study whether these compounds could have synergistic anticancer activity in TNBC cells and the possible role of NQO1. For this pourpose, we assessed the impact of β-LP (0.5 or 1.5 μM) and HT (50 and 100 μM) on five TNBC cell lines. We demonstrated that the combination of β-LP and HT exhibits anti-proliferative, pro-apoptotic, and cell cycle arrest effects in several TNBC cells, including docetaxel-resistant TNBC cells. Additionally, it effectively inhibits the self-renewal and clonogenicity of CSCs, modifying their aggressive phenotype. However, the notable impact of the β-LP-HT combination does not appear to be solely associated with the levels of the NQO1 protein and ROS. RNA-Seq analysis revealed that the combination's anticancer activity is linked to a strong induction of endoplasmic reticulum stress and apoptosis through the unfolded protein response. In conclusion, in this study, we demonstrated how the combination of β-LP and HT could offer an affordable, safe, and effective approach against TNBC.

Effects of sn-2 Palmitic Triacylglycerols and the Ratio of OPL to OPO in Human Milk Fat Substitute on Metabolic Regulation in Sprague-Dawley Rats

In this study, the influence of total sn-2 palmitic triacylglycerols (TAGs) and ratio of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) to 1,3-dioleoyl-2-palmitoylglycerol (OPO) in human milk fat substitute (HMFS) on the metabolic changes were investigated in Sprague-Dawley rats. Metabolomics and lipidomics profiling analysis indicated that increasing the total sn-2 palmitic TAGs and OPL to OPO ratio in HMFS could significantly influence glycine, serine and threonine metabolism, glycerophospholipid metabolism, glycerolipid metabolism, sphingolipid metabolism, bile acid biosynthesis, and taurine and hypotaurine metabolism pathways in rats after 4 weeks of feeding, which were mainly related to lipid, bile acid and energy metabolism. Meanwhile, the up-regulation of taurine, L-tryptophan, and L-cysteine, and down-regulations of lysoPC (18:0) and hypoxanthine would contribute to the reduction in inflammatory response and oxidative stress, and improvement of immunity function in rats. In addition, analysis of targeted biochemical factors also revealed that HMFS-fed rats had significantly increased levels of anti-inflammatory factor (IL-4), immunoglobulin A (IgA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), and decreased levels of pro-inflammatory factors (IL-6 and TNF-α) and malondialdehyde (MDA), compared with those of the control fat-fed rats. Collectively, these observations present new in vivo nutritional evidence for the metabolic regulatory effects of the TAG structure and composition of human milk fat substitutes on the host.

Hormetic Nutrition and Redox Regulation in Gut-Brain Axis Disorders

The antioxidant and anti-inflammatory effects of hormetic nutrition for enhancing stress resilience and overall human health have received much attention. Recently, the gut-brain axis has attracted prominent interest for preventing and therapeutically impacting neuropathologies and gastrointestinal diseases. Polyphenols and polyphenol-combined nanoparticles in synergy with probiotics have shown to improve gut bioavailability and blood-brain barrier (BBB) permeability, thus inhibiting the oxidative stress, metabolic dysfunction and inflammation linked to gut dysbiosis and ultimately the onset and progression of central nervous system (CNS) disorders. In accordance with hormesis, polyphenols display biphasic dose-response effects by activating at a low dose the Nrf2 pathway resulting in the upregulation of antioxidant vitagenes, as in the case of heme oxygenase-1 upregulated by hidrox® or curcumin and sirtuin-1 activated by resveratrol to inhibit reactive oxygen species (ROS) overproduction, microbiota dysfunction and neurotoxic damage. Importantly, modulation of the composition and function of the gut microbiota through polyphenols and/or probiotics enhances the abundance of beneficial bacteria and can prevent and treat Alzheimer's disease and other neurological disorders. Interestingly, dysregulation of the Nrf2 pathway in the gut and the brain can exacerbate selective susceptibility under neuroinflammatory conditions to CNS disorders due to the high vulnerability of vagal sensory neurons to oxidative stress. Herein, we aimed to discuss hormetic nutrients, including polyphenols and/or probiotics, targeting the Nrf2 pathway and vitagenes for the development of promising neuroprotective and therapeutic strategies to suppress oxidative stress, inflammation and microbiota deregulation, and consequently improve cognitive performance and brain health. In this review, we also explore interactions of the gut-brain axis based on sophisticated and cutting-edge technologies for novel anti-neuroinflammatory approaches and personalized nutritional therapies.

Dietary selenomethionine reduced oxidative stress by resisting METTL3-mediated m6A methylation level of Nrf2 to ameliorate LPS-induced liver necroptosis in laying hens

Selenomethionine (SeMet) as the main form of daily dietary selenium, occupies essential roles in providing antioxidant and anti-inflammatory properties, which alleviates inflammatory liver damage. N6-methyladenosine (m6A) is one of the most prevalent and abundant internal transcriptional modifications that regulate gene expression. To investigate the protective mechanism of SeMet on liver injury and the regulatory effect of m6A methylation modification, we established the model by supplementing dietary SeMet, and LPS as stimulus in laying hens. LMH cells were intervened with SeMet (0.075 µM) and/or LPS (60 µg/mL). Subsequently, histopathology and ultrastructure of liver were observed. Western Blot, qRT-PCR, colorimetry, MeRIP-qPCR, fluorescent probe staining and AO/EB were used to detect total m6A methylation level, m6A methylation level of Nrf2, ROS, inflammatory and necroptosis factors. Studies showed that SeMet suppressed LPS-induced upregulation of total m6A methylation levels and METTL3 expression. Interestingly, SeMet reduced the m6A methylation level of Nrf2, activated antioxidant pathways and alleviated oxidative stress. LMH cells were transfected with 50 µm siMETTL3. SeMet/SiMETTL3 reversed the LPS-induced reduction in Nrf2 mRNA stability, slowed down its degradation rate. Moreover, LPS induced oxidative stress, led to necroptosis and activated NF-κB to promote the expression of inflammatory factors. SeMet/SiMETTL3 alleviated LPS-induced necroptosis and inflammation. Altogether, SeMet enhanced antioxidant and anti-inflammatory capacity by reducing METTL3-mediated m6A methylation levels of Nrf2, ultimately alleviating liver damage. Our findings provided new insights and therapeutic target for the practical application of dietary SeMet in the treatment and prevention of liver inflammation, and supplied a reference for comparative medicine.

ECHOPvir: A Mixture of Echinacea and Hop Extracts Endowed with Cytoprotective, Immunomodulatory and Antiviral Properties

Respiratory viral infections continue to pose significant challenges, particularly for more susceptible and immunocompromised individuals. Nutraceutical strategies have been proposed as promising strategies to mitigate their impact and improve public health. In the present study, we developed a mixture of two hydroalcoholic extracts from the aerial parts of Echinacea purpurea (L.) Moench (ECP) and the cones of Humulus lupulus L. (HOP) that can be harnessed in the prevention and treatment of viral respiratory diseases. The ECP/HOP mixture (named ECHOPvir) was characterized for the antioxidant and cytoprotective properties in airway cells. Moreover, the immunomodulating properties of the mixture in murine macrophages against antioxidant and inflammatory stimuli and its antiviral efficacy against the PR8/H1N1 influenza virus were assayed. The modulation of the Nrf2 was also investigated as a mechanistic hypothesis. The ECP/HOP mixture showed a promising multitarget bioactivity profile, with combined cytoprotective, antioxidant, immunomodulating and antiviral activities, likely due to the peculiar phytocomplexes of both ECP and HOP, and often potentiated the effect of the single extracts. The Nrf2 activation seemed to trigger these cytoprotective properties and suggest a possible usefulness in counteracting the damage caused by different stressors, including viral infection. Further studies may strengthen the interest in this product and underpin its future nutraceutical applications.

Maternal Supplementation of Vitamin E or Its Combination with Hydroxytyrosol Increases the Gut Health and Short Chain Fatty Acids of Piglets at Weaning

An adequate intestinal environment before weaning may contribute to diarrhea predisposition and piglet development. This study evaluates how the dietary supplementation of vitamin E (VE) (100 mg/kg), hydroxytyrosol (HXT) (1.5 mg/kg) or the combined administration (VE + HXT) given to Iberian sows from gestation affects the piglet's faecal characteristics, short chain fatty acids (SCFAs), fatty acid profile or intestinal morphology as indicators of gut health; and quantify the contribution of the oxidative status and colostrum/milk composition to the piglet's SCFAs content and intestinal health. Dietary VE increased isobutyric acid (iC4), butyric acid (C4), isovaleric acid (iC5), and ∑SCFAs, whereas HXT increased iC4 and tended to decrease ∑SCFAs of faeces. Piglets from HXT-supplemented sows also tended to have higher faecal C20:4n-6/C20:2 ratio C22:6 proportion and showed lower occludin gene expression in the duodenum. The combination of both antioxidants had a positive effect on iC4 and iC5 levels. Correlation analyses and regression equations indicate that faecal SCFAs were related to oxidative status (mainly plasma VE) and colostrum and milk composition (mainly C20:2, C20:3, C20:4 n-6). This study would confirm the superiority of VE over HXT supplementation to improve intestinal homeostasis, gut health, and, consequently piglet growth.

Caffeic acid supplementation ameliorates intestinal injury by modulating intestinal microbiota in LPS-challenged piglets

During weaning, piglets are susceptible to intestinal injuries caused by a range of infections, which result in serious economic losses for pig producers. Caffeic acid (CA) is a plant-derived phenolic acid that exhibits potential as a dietary supplement for enhancing intestinal health. There is, however, limited information available about the potential benefits of CA supplementation on intestinal injury and growth performance in piglets. A 28-day study was conducted to examine the effectiveness of CA supplementation in protecting against intestinal injury induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) in piglets. Twenty-four piglets (7.43 ± 0.79 kg body weight; Duroc × Landrace × Large White; barrows) were randomly divided into 4 groups: the control group, the LPS group, the LPS + CA group, and the CA group. Piglets were administered with LPS or saline on d21 and d28 of the experiment. Supplementation with CA improved intestinal barrier function in LPS-challenged piglets by enhancing intestinal morphology and integrity, as well as increasing the expression of Claudin-1 and ZO-1. Meanwhile, CA supplementation improved the systemic and colonic inflammation responses, oxidative stress, and apoptosis induced by LPS. CA supplementation improved the alpha diversity and structure of the intestinal microbiota by increasing the abundance of beneficial microbiota. Additionally, it was found that it improves metabolic disorders of colonic bile acids (BAs) and short-chain fatty acids (SCFAs) in LPS-challenged piglets, including an increase in primary BAs and isovalerate. In conclusion, CA supplementation could enhance intestinal integrity and barrier function by modifying intestinal microbiota and its metabolites, which could lead to a reduction in inflammatory responses and oxidative stress and ultimately enhanced growth performance in piglets.

Role of Hydroxytyrosol and Oleuropein in the Prevention of Aging and Related Disorders: Focus on Neurodegeneration, Skeletal Muscle Dysfunction and Gut Microbiota

Aging is a multi-faceted process caused by the accumulation of cellular damage over time, associated with a gradual reduction of physiological activities in cells and organs. This degeneration results in a reduced ability to adapt to homeostasis perturbations and an increased incidence of illnesses such as cognitive decline, neurodegenerative and cardiovascular diseases, cancer, diabetes, and skeletal muscle pathologies. Key features of aging include a chronic low-grade inflammation state and a decrease of the autophagic process. The Mediterranean diet has been associated with longevity and ability to counteract the onset of age-related disorders. Extra virgin olive oil, a fundamental component of this diet, contains bioactive polyphenolic compounds as hydroxytyrosol (HTyr) and oleuropein (OLE), known for their antioxidant, anti-inflammatory, and neuroprotective properties. This review is focused on brain, skeletal muscle, and gut microbiota, as these systems are known to interact at several levels. After the description of the chemistry and pharmacokinetics of HTyr and OLE, we summarize studies reporting their effects in in vivo and in vitro models of neurodegenerative diseases of the central/peripheral nervous system, adult neurogenesis and depression, senescence and lifespan, and age-related skeletal muscle disorders, as well as their impact on the composition of the gut microbiota.

Hydroxytyrosol and Its Potential Uses on Intestinal and Gastrointestinal Disease

In recent years, the phytoconstituents of foods in the Mediterranean diet (MD) have been the subject of several studies for their beneficial effects on human health. The traditional MD is described as a diet heavy in vegetable oils, fruits, nuts, and fish. The most studied element of MD is undoubtedly olive oil due precisely to its beneficial properties that make it an object of interest. Several studies have attributed these protective effects to hydroxytyrosol (HT), the main polyphenol contained in olive oil and leaves. HT has been shown to be able to modulate the oxidative and inflammatory process in numerous chronic disorders, including intestinal and gastrointestinal pathologies. To date, there is no paper that summarizes the role of HT in these disorders. This review provides an overview of the anti-inflammatory and antioxidant proprieties of HT against intestinal and gastrointestinal diseases.