Hydroxytyrosol inhibits hydrogen peroxide-induced apoptotic signaling via labile iron chelation

Influence of Oleacein, an Olive Oil and Olive Mill Wastewater Phenolic Compound, on Caenorhabditis elegans Longevity and Stress Resistance

Oleacein, a bioactive compound of olive oil and olive mill wastewater, has one of the strongest antioxidant activities among olive phenolics. However, few reports explore the in vivo antioxidant activity of oleacein, with no clear identification of the biological pathway involved. Earlier studies have demonstrated a link between stress resistance, such as oxidative stress, and longevity. This study presents the effects of oleacein on Caenorhabditis elegans mean lifespan and stress resistance. A significant lifespan extension was observed with an increase of 20% mean lifespan at 5 µg/mL with a hormetic-like dose-dependent effect. DAF-16 and SIR-2.1 were involved in the effects of oleacein on the longevity of C. elegans, while the DAF-2 receptor was not involved. This study also shows the capacity of oleacein to significantly enhance C. elegans resistance to oxidative and thermal stress and allows a better understanding of the positive effects of olive phenolics on health.

Beneficial Effect of Olive Oil and Its Derivates: Focus on Hematological Neoplasm

Olive oil (Olea europaea) is one of the major components of the Mediterranean diet and is composed of a greater percentage of monounsaturated fatty acids, such as oleic acid; polyunsaturated fatty acids, such as linoleic acid; and minor compounds, such as phenolic compounds, and particularly hydroxytyrosol. The latter, in fact, are of greater interest since they have found widespread use in popular medicine. In recent years, it has been documented that phenolic acids and in particular hydroxytyrosol have anti-inflammatory, antioxidant, and antiproliferative action and therefore interest in their possible use in clinical practice and in particular in neoplasms, both solid and hematological, has arisen. This work aims to summarize and analyze the studies present in the literature, both in vitro and in vivo, on the possible use of minor components of olive oil in some hematological neoplasms. In recent years, in fact, interest in nutraceutical science has expanded as a possible adjuvant in the treatment of neoplastic pathologies. Although it is worth underlining that, regarding the object of our study, there are still few preclinical and clinical studies, it is, however, possible to document a role of possible interest in clinical practice.

Anti-Cancer, Anti-Angiogenic, and Anti-Atherogenic Potential of Key Phenolic Compounds from Virgin Olive Oil

The Mediterranean diet, renowned for its health benefits, especially in reducing cardiovascular risks and protecting against diseases like diabetes and cancer, emphasizes virgin olive oil as a key contributor to these advantages. Despite being a minor fraction, the phenolic compounds in olive oil significantly contribute to its bioactive effects. This review examines the bioactive properties of hydroxytyrosol and related molecules, including naturally occurring compounds (-)-oleocanthal and (-)-oleacein, as well as semisynthetic derivatives like hydroxytyrosyl esters and alkyl ethers. (-)-Oleocanthal and (-)-oleacein show promising anti-tumor and anti-inflammatory properties, which are particularly underexplored in the case of (-)-oleacein. Additionally, hydroxytyrosyl esters exhibit similar effectiveness to hydroxytyrosol, while certain alkyl ethers surpass their precursor's properties. Remarkably, the emerging research field of the effects of phenolic molecules related to virgin olive oil on cell autophagy presents significant opportunities for underscoring the anti-cancer and neuroprotective properties of these molecules. Furthermore, promising clinical data from studies on hydroxytyrosol, (-)-oleacein, and (-)-oleocanthal urge further investigation and support the initiation of clinical trials with semisynthetic hydroxytyrosol derivatives. This review provides valuable insights into the potential applications of olive oil-derived phenolics in preventing and managing diseases associated with cancer, angiogenesis, and atherosclerosis.

Yucca schidigera purpurea-sourced arabinogalactan polysaccharides augments antioxidant capacity facilitating intestinal antioxidant functions

This study isolated and purified a novel homogeneous arabinogalactan polysaccharide from Yucca schidigera extract (YSE), unveiled its unique structure and explored its antioxidant function. Firstly, the antioxidant potential of YSE was demonstrated in piglet trials. A homogeneous polysaccharide with a molecular weight of 24.2 kDa, designated as Yucca schidigera polysaccharide B (YPB), was isolated and purified from YSE. The monosaccharide composition of YPB was Rha, Araf, Galp, and Glcp, whose molar percentages were 2.8 %, 11.6 %, 45.5 %, and 40.0 %, respectively. Methylation analysis combined with 1D and 2D nuclear magnetic resonance showed that YPB was a complex polysaccharide with a main glycosidic linkage pattern of →2)-α-ʟ-Rha-(1 → 3)-β-ᴅ-Galp-(1→3)-β-ᴅ-Galp-(1 → 3)-β-ᴅ-Galp-(1 → 3)-β-ᴅ-Glcp-(1→, and branched Araf and Galp fragments were connected with the main chain through →3,6)-β-ᴅ-Galp-(1→, →3,4)-β-ᴅ-Glcp-(1→, and →2,4)-α-ʟ-Rha-(1→ linkages. Following the in vitro biochemical assays of bioactive components, YPB should be the contributor to the antioxidant activity in YSE. Based on the establishment of oxidative stress model, YPB exhibited strong antioxidant capacity and activated NRF2 pathway, and then provided protection against the damage induced oxidative stress in IPEC-J2 cells and rats. Further analysis with inhibitors found that this antioxidant effect was attributed to its interaction with epidermal growth factor receptor and mannose receptor, and stimulating PI3K/AKT pathway.

Protective effects of macromolecular polyphenols, metals (zinc, selenium, and copper) - Polyphenol complexes, and different organs with an emphasis on arsenic poisoning: A review

For the potential health benefits and nutritional value, polyphenols are one of the secondary metabolites of plants that have received extensive research. It has anti-inflammatory and cytotoxicity-reducing properties in addition to a high antioxidant content. Macromolecular polyphenols and polysaccharides are biologically active natural polymers with antioxidant and anti-inflammatory potential. Arsenic is an ecologically toxic metalloid. Arsenic in drinking water is the most common way people come into contact with this metalloid. While arsenic is known to cause cancer, it is also used to treat acute promyelocytic leukemia (APL). The treatment's effectiveness is hampered by the adverse effects it can cause on the body. Oxidative stress, inflammation, and the inability to regulate cell death cause the most adverse effects. Polyphenols and other macromolecules like polysaccharides act as neuroprotectants by mitigating free radical damage, inhibiting nitric oxide (NO) production, lowering A42 fibril formation, boosting antioxidant levels, and controlling apoptosis and inflammation. To prevent the harmful effects of toxins, polyphenols and pectin lower oxidative stress, boost antioxidant levels, improve mitochondrial function, control apoptosis, and suppress inflammation. Therefore, it prevents damage to the heart, liver, kidneys, and reproductive system. This review aims to identify the effects of the polyphenols in conjugation with polysaccharides as an ameliorative strategy for arsenic-induced toxicity in various organs.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

Hydroxytyrosol Counteracts Triple Negative Breast Cancer Cell Dissemination via Its Copper Complexing Properties

Polyphenols have gained increasing attention for their therapeutic potential, particularly in conditions like cancer, due to their established antioxidant and anti-inflammatory properties. Recent research highlights their ability to bind to transition metals, such as copper. This is particularly noteworthy given the key role of copper both in the initiation and progression of cancer. Copper can modulate the activity of kinases required for the epithelial-mesenchymal transition (EMT), a process fundamental to tumor cell dissemination. We have previously demonstrated the copper-binding capacity of oleuropein, a secoiridoid found in Olea europaea. In the present study, we investigated the effect of hydroxytyrosol, the primary oleuropein metabolite, on the metastatic potential of three triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-468, and SUM159). We found that hydroxytyrosol modulated the intracellular copper levels, influencing both the epithelial and mesenchymal markers, by downregulating copper-dependent AKT phosphorylation, a member of the EMT signaling cascade, through Western blot, RT-qPCR, and immunofluorescence. Indeed, by optical spectra, EPR, and in silico approaches, we found that hydroxytyrosol formed a complex with copper, acting as a chelating agent, thus regulating its homeostasis and affecting the copper-dependent signaling cascades. While our results bring to light the copper-chelating properties of hydroxytyrosol capable of countering tumor progression, they also provide further confirmation of the key role of copper in promoting the aggressiveness of triple-negative breast cancer cells.

The Impact of Hydroxytyrosol on the Metallomic-Profile in an Animal Model of Alzheimer's Disease

It is undeniable that as people get older, they become progressively more susceptible to neurodegenerative illnesses such as Alzheimer's disease (AD). Memory loss is a prominent symptom of this condition and can be exacerbated by uneven levels of certain metals. This study used inductively coupled plasma mass spectrometry (ICP-MS) to examine the levels of metals in the blood plasma, frontal cortex, and hippocampus of Wistar rats with AD induced by streptozotocin (STZ). It also tested the effects of the antioxidant hydroxytyrosol (HT) on metal levels. The Barnes maze behavior test was used, and the STZ group showed less certainty and greater distance when exploring the Barnes maze than the control group. The results also indicated that the control group and the STZ + HT group exhibited enhanced learning curves during the Barnes maze training as compared to the STZ group. The ICP-MS analysis showed that the STZ group had lower levels of cobalt in their blood plasma than the control group, while the calcium levels in the frontal cortex of the STZ + HT group were higher than in the control group. The most important finding was that copper levels in the frontal cortex from STZ-treated animals were higher than in the control group, and that the STZ + HT group returned to equivalent levels to the control group. The antioxidant HT can restore copper levels to their basal physiological state. This finding may help explain HT's potential beneficial effect in AD-patients.

Immunomodulatory and Antioxidant Drugs in Glaucoma Treatment

Glaucoma, a group of diseases characterized by progressive retinal ganglion cell loss, cupping of the optic disc, and a typical pattern of visual field defects, is a leading cause of severe visual impairment and blindness worldwide. Elevated intraocular pressure (IOP) is the leading risk factor for glaucoma development. However, glaucoma can also develop at normal pressure levels. An increased susceptibility of retinal ganglion cells to IOP, systemic vascular dysregulation, endothelial dysfunction, and autoimmune imbalances have been suggested as playing a role in the pathophysiology of normal-tension glaucoma. Since inflammation and oxidative stress play a role in all forms of glaucoma, the goal of this review article is to present an overview of the inflammatory and pro-oxidant mechanisms in the pathophysiology of glaucoma and to discuss immunomodulatory and antioxidant treatment approaches.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

Anti-Inflammatory Effects of Nutritionally Relevant Concentrations of Oleuropein and Hydroxytyrosol on Peripheral Blood Mononuclear Cells: An Age-Related Analysis

Immunosenescence and inflammaging facilitate the insurgence of chronic diseases. The Mediterranean diet is a non-invasive intervention to improve the chronic low-grade inflammatory status associated with aging. Olive oil oleuropein (OLE) and hydroxytyrosol (HT) demonstrated a controversial modulatory action on inflammation in vitro when tested at concentrations exceeding those detectable in human plasma. We studied the potential anti-inflammatory effects of OLE and HT at nutritionally relevant concentrations on peripheral blood mononuclear cells (PBMCs) as regards cell viability, frequency of leukocyte subsets, and cytokine release, performing an age-focused analysis on two groups of subjects: Adult (age 18-64 years) and Senior (age ≥ 65 years). OLE and HT were used alone or as a pre-treatment before challenging PBMCs with lipopolysaccharide (LPS). Both polyphenols had no effect on cell viability irrespective of LPS, but 5 µM HT had an LPS-like effect on monocytes, reducing the intermediate subset in Adult subjects. OLE and HT had no effect on LPS-triggered release of TNF-α, IL-6 and IL-8, but 5 µM HT reduced IL-10 secretion by PBMCs from Adult vs. Senior group. In summary, nutritionally relevant concentrations of OLE and HT elicit no anti-inflammatory effect and influence the frequency of immune cell subsets with age-related different outcomes.

The Role of Oxidative Stress and Cellular Senescence in the Pathogenesis of Metabolic Associated Fatty Liver Disease and Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents a worryingly increasing cause of malignancy-related mortality, while Metabolic Associated Fatty Liver Disease (MAFLD) is going to become its most common cause in the next decade. Understanding the complex underlying pathophysiology of MAFLD-related HCC can provide opportunities for successful targeted therapies. Of particular interest in this sequela of hepatopathology is cellular senescence, a complex process characterised by cellular cycle arrest initiated by a variety of endogenous and exogenous cell stressors. A key biological process in establishing and maintaining senescence is oxidative stress, which is present in multiple cellular compartments of steatotic hepatocytes. Oxidative stress-induced cellular senescence can change hepatocyte function and metabolism, and alter, in a paracrine manner, the hepatic microenvironment, enabling disease progression from simple steatosis to inflammation and fibrosis, as well as HCC. The duration of senescence and the cell types it affects can tilt the scale from a tumour-protective self-restricting phenotype to the creator of an oncogenic hepatic milieu. A deeper understanding of the mechanism of the disease can guide the selection of the most appropriate senotherapeutic agent, as well as the optimal timing and cell type targeting for effectively combating HCC.

Oxidative Stress-Induced Cellular Senescence: Is Labile Iron the Connecting Link?

Cellular senescence, a cell state characterized by a generally irreversible cell cycle arrest, is implicated in various physiological processes and a wide range of age-related pathologies. Oxidative stress, a condition caused by an imbalance between the production and the elimination of reactive oxygen species (ROS) in cells and tissues, is a common driver of cellular senescence. ROS encompass free radicals and other molecules formed as byproducts of oxygen metabolism, which exhibit varying chemical reactivity. A prerequisite for the generation of strong oxidizing ROS that can damage macromolecules and impair cellular function is the availability of labile (redox-active) iron, which catalyzes the formation of highly reactive free radicals. Targeting labile iron has been proven an effective strategy to counteract the adverse effects of ROS, but evidence concerning cellular senescence is sparse. In the present review article, we discuss aspects of oxidative stress-induced cellular senescence, with special attention to the potential implication of labile iron.

Cytoprotective Role of Heme Oxygenase-1 in Cancer Chemoresistance: Focus on Antioxidant, Antiapoptotic, and Pro-Autophagy Properties

Chemoresistance remains the foremost challenge in cancer therapy. Targeting reactive oxygen species (ROS) manipulation is a promising strategy in cancer treatment since tumor cells present high levels of intracellular ROS, which makes them more vulnerable to further ROS elevation than normal cells. Nevertheless, dynamic redox evolution and adaptation of tumor cells are capable of counteracting therapy-induced oxidative stress, which leads to chemoresistance. Hence, exploring the cytoprotective mechanisms of tumor cells is urgently needed to overcome chemoresistance. Heme oxygenase-1 (HO-1), a rate-limiting enzyme of heme degradation, acts as a crucial antioxidant defense and cytoprotective molecule in response to cellular stress. Recently, emerging evidence indicated that ROS detoxification and oxidative stress tolerance owing to the antioxidant function of HO-1 contribute to chemoresistance in various cancers. Enhanced HO-1 expression or enzymatic activity was revealed to promote apoptosis resistance and activate protective autophagy, which also involved in the development of chemoresistance. Moreover, inhibition of HO-1 in multiple cancers was identified to reversing chemoresistance or improving chemosensitivity. Here, we summarize the most recent advances regarding the antioxidant, antiapoptotic, and pro-autophagy properties of HO-1 in mediating chemoresistance, highlighting HO-1 as a novel target for overcoming chemoresistance and improving the prognosis of cancer patients.

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.

Effects of Hydroxytyrosol in Endothelial Functioning: A Comprehensive Review

Pharmacologists have been emphasizing and applying plant and herbal-based treatments in vascular diseases for decades now. Olives, for example, are a traditional symbol of the Mediterranean diet. Hydroxytyrosol is an olive-derived compound known for its antioxidant and cardioprotective effects. Acknowledging the merit of antioxidants in maintaining endothelial function warrants the application of hydroxytyrosol in endothelial dysfunction salvage and recovery. Endothelial dysfunction (ED) is an impairment of endothelial cells that adversely affects vascular homeostasis. Disturbance in endothelial functioning is a known precursor for atherosclerosis and, subsequently, coronary and peripheral artery disease. However, the effects of hydroxytyrosol on endothelial functioning were not extensively studied, limiting its value either as a nutraceutical supplement or in clinical trials. The action of hydroxytyrosol in endothelial functioning at a cellular and molecular level is gathered and summarized in this review. The favorable effects of hydroxytyrosol in the improvement of endothelial functioning from in vitro and in vivo studies were scrutinized. We conclude that hydroxytyrosol is capable to counteract oxidative stress, inflammation, vascular aging, and arterial stiffness; thus, it is beneficial to preserve endothelial function both in vitro and in vivo. Although not specifically for endothelial dysfunction, hydroxytyrosol safety and efficacy had been demonstrated via in vivo and clinical trials for cardiovascular-related studies.

Multiscale Modeling Unravels the Influence of Biomembranes on the Photochemical Properties of Embedded Anti-Oxidative Polyphenolic and Phenanthroline Chelating Dyes

The embedding of caffeate methyl ester, the flavonoids luteolin and quercetin, and the o-phenanthroline and neocuproine in a liquid disordered lipid bilayer has been studied through extensive atomistic calculations. The location and the orientation of these bio-active antioxidants are explained and analyzed. While the two phenanthrolines strongly associate with the lipid tail region, the other three compounds are rather found among the head groups. The simulations showcase conformational changes of the flavonoids. Through the use of a hybrid quantum mechanics-molecular mechanics scheme and supported by a profound benchmarking of the electronic excited-state method for these compounds, the influence of the anisotropic environment on the compounds' optical properties is analyzed. Influences of surrounding water molecules and of the polar parts of the lipids on the transition dipole moments and excited-state dipole moments are weighted with respect to a change in conformation. The current study highlights the importance of the mapping of molecular interactions in model membranes and pinpoints properties, which can be biomedically used to discriminate and detect different lipid environments.

Effects of Oleuropein and Hydroxytyrosol on Inflammatory Mediators: Consequences on Inflammaging

Aging is associated with a low-grade, systemic inflammatory state defined as "inflammaging", ruled by the loss of proper regulation of the immune system leading to the accumulation of pro-inflammatory mediators. Such a condition is closely connected to an increased risk of developing chronic diseases. A number of studies demonstrate that olive oil phenolic compound oleuropein and its derivative hydroxytyrosol contribute to modulating tissue inflammation and oxidative stress, thus becoming attractive potential candidates to be used in the context of nutraceutical interventions, in order to ameliorate systemic inflammation in aging subjects. In this review, we aim to summarize the available data about the anti-inflammatory properties of oleuropein and hydroxytyrosol, discussing them in the light of molecular pathways involved in the synthesis and release of inflammatory mediators in inflammaging.

Combined administration of membrane-permeable and impermeable iron-chelating drugs attenuates ischemia/reperfusion-induced hepatic injury

BACKGROUND

The underlying pathophysiological mechanisms of hepatic ischemia-reperfusion (I/R) injury have not been completely elucidated. However, it is well known that oxidative stress, caused by a burst of reactive oxygen species (ROS) production during the reperfusion phase, plays a crucial role. A growing body of evidence indicates that the intracellular availability of free iron represents a requirement for ROS-induced adverse effects, as iron catalyzes the generation of highly reactive free radicals. The aim of this study was to examine whether a combination of iron chelators with varying lipophilicity could offer enhanced protection against I/R by diminishing the conversion of weak oxidants, like H₂O₂, to extremely reactive ones such as hydroxyl radicals (HO^.).

METHODS

HepG2 cells (hepatocellular carcinoma cell line) were exposed to oxidative stress conditions after pre-treatment with the iron chelators desferrioxamine (DFO) and deferiprone (DFP) alone or in combination. Labile iron pool was estimated using the calcein-acetoxymethyl ester (calcein-AM) method and DNA damage with the comet assay. We subsequently used a rabbit model (male New Zealand white rabbits) of hepatic I/R-induced injury to investigate, by measuring biochemical (ALT, ALT, ALP, γGT) and histological parameters, whether this may be true for in vivo conditions.

RESULTS

The combination of a membrane-permeable iron chelator (DFP) with a strong membrane-impermeable one (DFO) raises the level of protection in both hepatic cell lines exposed to oxidative stress conditions and hepatic I/R rabbit model.

CONCLUSIONS

Our results show that combinations of iron chelators with selected lipophilicity and iron-binding properties may represent a valuable strategy to protect against tissue damage during reperfusion after a period of ischemia.

Shigella iron-binding proteins: An insight into molecular physiology, pathogenesis, and potential target vaccine development

Shigella is a well-known etiological agent responsible for intestinal infection among children, the elderly, and immunocompromised people ranging from mild to severe cases. Shigellosis remains endemic in Malaysia and yet there is no commercial vaccine available to eradicate the disease. Iron is an essential element for the survival of Shigella within the host. Hence, it is required for regulating metabolic mechanisms and virulence determinants. Alteration of iron status in the extracellular environment directly triggers the signal in enteropathogenic bacterial, providing information that they are in a hostile environment. To survive in an iron-limited environment, molecular regulation of iron-binding proteins plays a vital role in facilitating the transportation and utilization of sufficient iron sources. Given the importance of iron molecules for bacterial survival and pathogenicity, this review summarizes the physiological role of iron-binding proteins in bacterial survival and their potential use in vaccine and therapeutic developments.

Involvement of the PI3K/AKT Intracellular Signaling Pathway in the AntiCancer Activity of Hydroxytyrosol, a Polyphenol from Olea europaea, in Hematological Cells and Implication of HSP60 Levels in Its Anti-Inflammatory Activity

Hydroxytyrosol (HT), the main representative of polyphenols of olive oil, has been described as one of the most powerful natural antioxidants, also showing anti-inflammatory, antimicrobial, cardioprotective and anticancer activity in different type of cancers, but has been little studied in hematological neoplasms. The objective of this work was to evaluate the anticancer potential of HT in acute human leukemia T cells (Jurkat and HL60) and the anti-inflammatory potential in murine macrophages (Raw264.7). For this, cytotoxicity tests were performed for HT, showing IC₅₀ values, at 24 h, for Jurkat, HL60 and Raw264.7 cells, of 27.3 µg·mL⁻¹, 109.8 µg·mL⁻¹ and 45.7 µg·mL⁻¹, respectively. At the same time, HT caused cell arrest in G₀/G₁ phase in both Jurkat and HL60 cells by increasing G₀/G₁ phase and significantly decreasing S phase. Apoptosis and cell cycle assays revealed an antiproliferative effect of HT, decreasing the percentage of dividing cells and increasing apoptosis. Furthermore, HT inhibited the PI3K signaling pathway and, consequently, the MAPK pathway was activated. Inflammation tests revealed that HT acts as an anti-inflammatory agent, reducing NO levels in Raw264.7 cells previously stimulated by lipopolysaccharide (LPS). These processes were confirmed by the changes in the expression of the main markers of inflammation and cancer. In conclusion, HT has an anticancer and anti-inflammatory effect in the cell lines studied, which were Raw264.7, Jurkat, and HL60, and could be used as a natural drug in the treatment of liquid cancers, leukemias, myelomas and lymphomas.

Hydroxytyrosol Prevents Doxorubicin-Induced Oxidative Stress and Apoptosis in Cardiomyocytes

Doxorubicin (Dox) is a highly effective chemotherapeutic agent employed in the handling of hematological and solid tumors. The effective use of Dox in cancer therapy has been seriously limited due to its well-known cardiotoxic side effects, mainly mediated by oxidative damage. Therefore, the identification of an effective and safe antagonist against Dox-induced cardiotoxicity remains a challenge. In this respect, as plant polyphenols have attracted considerable interest due to their antioxidant properties and good safety profile, hydroxytyrosol (HT), the major phenolic compound in olive oil, could be a potential candidate due to its remarkable antioxidant and anticancer powers. In this study, the effect of HT was tested on Dox-induced cardiotoxicity by using a combination of biochemical and cellular biology techniques. Interestingly, HT was able to counteract Dox-induced cytotoxicity in cardiomyocytes by acting on the SOD2 level and the oxidative response, as well as on apoptotic mechanisms mediated by Bcl-2/Bax. At the same time, HT did not to interfere with the antitumorigenic properties of Dox in osteosarcoma cells. This study identifies new, beneficial properties for HT and suggests that it might be a promising molecule for the development of additional therapeutic approaches aimed at preventing anthracycline-related cardiotoxicity and improving long-term outcomes in antineoplastic treatments.

Production of biologically active hydroxytyrosol rich extract via catalytic conversion of tyrosol

An effective and economical process was established to produce hydroxytyrosol, a naturally occurring orthodiphenolic antioxidant molecule found in olive oil from its monophenolic precursor tyrosol. The approach proposed in the present work presents an environment-friendly method based on wet hydrogen peroxide catalytic oxidation with montmorillonite KSF as an inexpensive and environmentally benign solid acid at room temperature. The influence of the principal operating parameters including concentration of tyrosol, H₂O₂, and catalyst used were studied. The antioxidant activity was realized by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. High antioxidant activity was detected according to the high hydroxytyrosol production (IC₅₀ = 0.7 μg mL⁻¹). The bactericidal and fungicidal properties of hydroxytyrosol rich extract were investigated using the NCCLS broth dilution and EN 1276 standard methods. Positive bactericidal and fungicidal effects of concentrations ranging between 1–0.5 g L⁻¹ and 4–2 g L⁻¹ were obtained.

An effective and economical process was established to produce hydroxytyrosol, a natural antioxidant molecule.

Potential of Olive Oil Mill Wastewater as a Source of Polyphenols for the Treatment of Skin Disorders: A Review

Current trends toward naturally occurring compounds of therapeutic interest have contributed to an increasing number of studies on olive oil phenolics in the treatment of diseases with oxidative and inflammatory origins. Recent focus has been on olive oil wastewater, which is richer in phenolic compounds than olive oil itself. In this review, we present findings demonstrating the potential use of olive mill wastewater in dermatology. Particular attention is given to compounds with proven benefits in topical pharmacology: caffeic and ferulic acids, tyrosol and hydroxytyrosol, verbascoside, and oleuropein. The review is divided into different sections: inflammatory skin diseases, microbial effects, wound healing in addition to the antimelanoma properties of olive mill waste phenolics, and their potential in sun protection agents. There is strong evidence to support further studies into the valorization of this abundant and sustainable source of phenolic compounds for use in dermatology and dermo-cosmetic preparations.

Micellar Nanocarriers of Hydroxytyrosol Are Protective against Parkinson's Related Oxidative Stress in an In Vitro hCMEC/D3-SH-SY5Y Co-Culture System

Hydroxytyrosol (HT) is a natural phenolic antioxidant which has neuroprotective effects in models of Parkinson’s disease (PD). Due to issues such as rapid metabolism, HT is unlikely to reach the brain at therapeutic concentrations required for a clinical effect. We have previously developed micellar nanocarriers from Pluronic F68^® (P68) and dequalinium (DQA) which have suitable characteristics for brain delivery of antioxidants and iron chelators. The aim of this study was to utilise the P68 + DQA nanocarriers for HT alone, or in combination with the iron chelator deferoxamine (DFO), and assess their physical characteristics and ability to pass the blood–brain barrier and protect against rotenone in a cellular hCMEC/D3-SH-SY5Y co-culture system. Both HT and HT + DFO formulations were less than 170 nm in size and demonstrated high encapsulation efficiencies (up to 97%). P68 + DQA nanoformulation enhanced the mean blood–brain barrier (BBB) passage of HT by 50% (p < 0.0001, n = 6). This resulted in increased protection against rotenone induced cytotoxicity and oxidative stress by up to 12% and 9%, respectively, compared to the corresponding free drug treatments (p < 0.01, n = 6). This study demonstrates for the first time the incorporation of HT and HT + DFO into P68 + DQA nanocarriers and successful delivery of these nanocarriers across a BBB model to protect against PD-related oxidative stress. These nanocarriers warrant further investigation to evaluate whether this enhanced neuroprotection is exhibited in in vivo PD models.

Molecular Action of Hydroxytyrosol in Attenuation of Intimal Hyperplasia: A Scoping Review

Objective: Hydroxytyrosol (HT), a polyphenol of olive plant is well known for its antioxidant, anti-inflammatory and anti-atherogenic properties. The aim of this systematic search is to highlight the scientific evidence evaluating molecular efficiency of HT in halting the progression of intimal hyperplasia (IH), which is a clinical condition arises from endothelial inflammation.

Methods: A systematic search was performed through PubMed, Web of Science and Scopus, based on pre-set keywords which are Hydroxytyrosol OR 3,4-dihydroxyphenylethanol, AND Intimal hyperplasia OR Neointimal hyperplasia OR Endothelial OR Smooth muscles. Eighteen in vitro and three in vitro and in vivo studies were selected based on a pre-set inclusion and exclusion criteria.

Results: Based on evidence gathered, HT was found to upregulate PI3K/AKT/mTOR pathways and supresses inflammatory factors and mediators such as IL-1β, IL-6, E-selectin, P-selectin, VCAM-1, and ICAM-1 in endothelial vascularization and functioning. Two studies revealed HT disrupted vascular smooth muscle cells (SMC) cell cycle by dephosphorylating ERK1/2 and AKT pathways. Therefore, HT was proven to promote endothelization and inhibit vascular SMCs migration thus hampering IH development. However, none of these studies described the effect of HT collectively in both vascular endothelial cells (EC) and SMCs in IH ex vivo model.

Conclusions: Evidence from this concise review provides an insight on HT regulation of molecular pathways in reendothelization and inhibition of VSMCs migration. Henceforth, we propose effect of HT on IH prevention could be further elucidated through in vivo and ex vivo model.

Implication of Dietary Iron-Chelating Bioactive Compounds in Molecular Mechanisms of Oxidative Stress-Induced Cell Ageing

One of the prevailing perceptions regarding the ageing of cells and organisms is the intracellular gradual accumulation of oxidatively damaged macromolecules, leading to the decline of cell and organ function (free radical theory of ageing). This chemically undefined material known as "lipofuscin," "ceroid," or "age pigment" is mainly formed through unregulated and nonspecific oxidative modifications of cellular macromolecules that are induced by highly reactive free radicals. A necessary precondition for reactive free radical generation and lipofuscin formation is the intracellular availability of ferrous iron (Fe²⁺) ("labile iron"), catalyzing the conversion of weak oxidants such as peroxides, to extremely reactive ones like hydroxyl (HO^•) or alcoxyl (RO^•) radicals. If the oxidized materials remain unrepaired for extended periods of time, they can be further oxidized to generate ultimate over-oxidized products that are unable to be repaired, degraded, or exocytosed by the relevant cellular systems. Additionally, over-oxidized materials might inactivate cellular protection and repair mechanisms, thus allowing for futile cycles of increasingly rapid lipofuscin accumulation. In this review paper, we present evidence that the modulation of the labile iron pool distribution by nutritional or pharmacological means represents a hitherto unappreciated target for hampering lipofuscin accumulation and cellular ageing.

Application of Hydroxytyrosol in the Functional Foods Field: From Ingredient to Dietary Supplements

Hydroxytyrosol (HT) is an amphipathic functional phenol found in the olive tree, both in its leaves and fruits, in free or bound forms, as well as in olive oil and by-products of olive oil manufacture. The European Food Safety Authority recommends regular consumption of HT due to its several beneficial effects on human health, which are closely associated to its antioxidant activity. These reasons make HT an excellent candidate for application as a functional ingredient in the design of novel food products. Patents already exist for methodologies of extraction, purification, and application of HT in supplements and food products. The present review discusses the impact of HT incorporation on food properties and its effects on consumers, based on relevant data related to the use of HT as a functional ingredient, both as a pure compound or in the form of HT-rich extracts, in various food products, namely in edible oils, beverages, bakery products, as well animal-based foods such as meat, fishery and dairy products.

Bioinspired tailoring of fluorogenic thiol responsive antioxidant precursors to protect cells against H2O2-induced DNA damage

Natural antioxidants, like phenolic acids, possess a unique chemical space that can protect cellular components from oxidative stress. However, their polar carboxylic acid chemotype reduces full intracellular antioxidant potential due to limited diffusion through biological membranes. Here, we have designed and developed a new generation of hydrophobic turn-on fluorescent antioxidant precursors that upon penetration of the cell membrane, reveal a more polar and more potent antioxidant core and simultaneously become fluorescent allowing their intracellular tracking. Their activation is stimulated by polarity alteration by sensing intracellular signals and specifically biothiols. In our design, the carboxylic group of phenolic acids that originally restricts cell entrance is derivatized and conjugated through Copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) to a coumarin derivative that its fluorescence properties are quenched with a biothiol activatable element. This more hydrophobic precursor readily penetrates cell membrane and once inside the cell the antioxidant core is revealed upon sensing glutathione, its fluorescence is restored in a turn-on manner and the generation of a more polar character traps the molecule inside the cell. This turn-on fluorescent antioxidant precursor that can be applied to phenolic acids, was developed for rosmarinic acid and the conjugate was named as RCG. The selectivity and responsiveness of RCG towards the most abundant biothiols was monitored through a variety of biophysical techniques including UV-Vis, fluorescence and NMR spectroscopy. The electrochemical behavior and free radical scavenging capacity of the precursor RCG and the active compound (RC) was evaluated and compared with the parent compound (rosmarinic acid) through cyclic voltammetry and EPR spectroscopy, respectively. The stability of the newly synthesized bioactive conjugate RC was found significantly higher than the parent rosmarinic acid when exposed to oxygen. Cell uptake experiments were conducted and revealed the internalization of RCG. The degree of intracellular DNA protection offered by RCG and its active drug (RC) on exposure to H₂O₂ was also evaluated in Jurkat cells.

Delivery Systems for Hydroxytyrosol Supplementation: State of the Art

This review aims to highlight the benefits and limitations of the main colloid-based available delivery systems for hydroxytyrosol. Hydroxytyrosol is a phenolic compound with clear biological activities for human wellness. Olive fruits, leaves and extra-virgin oil are the main food sources of hydroxytyrosol. Moreover, olive oil mill wastewaters are considered a potential source to obtain hydroxytyrosol to use in the food industry. However, recovered hydroxytyrosol needs adequate formulations and delivery systems to increase its chemical stability and bioavailability. Therefore, the application of hydroxytyrosol delivery systems in food sector is still a fascinating challenge. Principal delivery systems are based on the use of colloids, polymers able to perform gelling, thickening and stabilizing functions in various industrial sectors, including food manufacturing. Here, we review the recipes for the available hydroxytyrosol systems and their relative production methods, as well as aspects relative to system characteristics and hydroxytyrosol effectiveness.

Implications of Oxidative Stress and Cellular Senescence in Age-Related Thymus Involution

The human thymus is a primary lymphoepithelial organ which supports the production of self-tolerant T cells with competent and regulatory functions. Paradoxically, despite the crucial role that it exerts in T cell-mediated immunity and prevention of systemic autoimmunity, the thymus is the first organ of the body that exhibits age-associated degeneration/regression, termed “thymic involution.” A hallmark of this early phenomenon is a progressive decline of thymic mass as well as a decreased output of naïve T cells, thus resulting in impaired immune response. Importantly, thymic involution has been recently linked with cellular senescence which is a stress response induced by various stimuli. Accumulation of senescent cells in tissues has been implicated in aging and a plethora of age-related diseases. In addition, several lines of evidence indicate that oxidative stress, a well-established trigger of senescence, is also involved in thymic involution, thus highlighting a possible interplay between oxidative stress, senescence, and thymic involution.

Deferasirox protects against hydrogen peroxide-induced cell apoptosis by inhibiting ubiquitination and degradation of p21WAF1/CIP1

Deferasirox (DFX) is an iron chelator approved for the treatment of iron overload diseases. However, the role of DFX in oxidative stress-induced cell apoptosis and the exact molecular mechanisms underlying these processes remain poorly understood and require further investigation. In this study, we found that DFX rendered resistant to H₂O₂-induced apoptosis in HEK293T cells, reduced the intracellular levels of the labile iron pool (LIP) and oxidative stress induced by H₂O₂. Furthermore, DFX inhibited the ubiquitination and degradation of the cyclin-dependent kinase inhibitor p21^WAF1/CIP1 (p21) via modulation of the interaction of p21 with SCF-Skp2. DFX also showed the inhibition effect on the activation of c-Jun N-terminal kinase (JNK), pro-caspase-3 and related mitochondrial apoptosis pathway induced by H₂O₂. These results provide novel insights into the molecular mechanism underpinning iron-mediated oxidative stress and apoptosis, and they may represent a promising target for therapeutic interventions in related pathological conditions.

Extra-Virgin Olive Oil Modifies the Changes Induced in Non-Nervous Organs and Tissues by Experimental Autoimmune Encephalomyelitis Models

This study reveals the existence of oxidative stress (reactive oxygen species (ROS)) in non-nervous organs and tissues in multiple sclerosis (MS) by means of a model of experimental autoimmune encephalomyelitis (EAE) in rats. This model reproduces a similar situation to MS, as well as its relationship with intestinal microbiota starting from the changes in bacterial lipopolysaccharide levels (LPS) in the outer wall of the gram-negative bacteria. Finally, the administration of extra-virgin olive oil (EVOO), hydroxytirosol (HT), and oleic acid (OA) exert beneficial effects. Twenty-five Dark Agouti two-month-old male rats, weighing around 190 g, were distributed into the following groups: Control, EAE (experimental autoimmune encephalomyelitis group), EAE + EVOO, EAE + HT, and EAE + OA. The glutathione redox system with the EAE was measured in heart, kidney, liver, and small and large intestines. The LPS and the correlation with oxidative stress in the small and large intestines were also investigated. The results showed that (1) the oxidative damage in the EAE model affects non-nervous organs and tissues; (2) The LPS is related to inflammatory phenomena and oxidative stress in the intestinal tissue and in other organs; (3) The administration of EVOO, HT, and OA reduces the LPS levels at the same time as minimizing the oxidative damage; (4) EVOO, HT, and OA improve the disease's clinical score; and (5) on balance, EVOO offers a better neuroprotective effect.

AKT-GSK3β Signaling Pathway Regulates Mitochondrial Dysfunction-Associated OPA1 Cleavage Contributing to Osteoblast Apoptosis: Preventative Effects of Hydroxytyrosol

Oxidative stress (OS) induces osteoblast apoptosis, which plays a crucial role in the initiation and progression of osteoporosis. Although OS is closely associated with mitochondrial dysfunction, detailed mitochondrial mechanisms underlying OS-induced osteoblast apoptosis have not been thoroughly elucidated to date. In the present study, we found that mitochondrial abnormalities largely contributed to OS-induced osteoblast apoptosis, as evidenced by enhanced production of mitochondrial reactive oxygen species; considerable reduction in mitochondrial respiratory chain complex activity, mitochondrial membrane potential, and adenosine triphosphate production; abnormality in mitochondrial morphology; and alteration of mitochondrial dynamics. These mitochondrial abnormalities were primarily mediated by an imbalance in mitochondrial fusion and fission through a protein kinase B- (AKT-) glycogen synthase kinase 3β- (GSK3β-) optic atrophy 1- (OPA1-) dependent mechanism. Hydroxytyrosol (3,4-dihydroxyphenylethanol (HT)), an important compound in virgin olive oil, significantly prevented OS-induced osteoblast apoptosis. Specifically, HT inhibited OS-induced mitochondrial dysfunction by decreasing OPA1 cleavage and by increasing AKT and GSK3β phosphorylation. Together, our results indicate that the AKT-GSK3β signaling pathway regulates mitochondrial dysfunction-associated OPA1 cleavage, which may contribute to OS-induced osteoblast apoptosis. Moreover, our results suggest that HT could be an effective nutrient for preventing osteoporosis development.

The protective effect of extra-virgin olive oil in the experimental model of multiple sclerosis in the rat

This study has evaluated the effect of EVOO (Extra-Virgin olive oil), OA (oleic acid) and HT (hydroxytyrosol) in an induced model of MS through experimental autoimmune encephalomyelitis (EAE).Dark Agouti 2-month old rats (25 males) were divided into five groups: (i) control group, (ii) EAE group, (iii) EAE+EVOO, (iv) EAE+HT, and (v) EAE+OA. At 65 days, the animals were sacrificed and the glutathione redox system and bacterial lipopolysaccharide (LPS) and LPS-binding protein (LBP) products of the microbiota in brain, spinal cord, and blood were evaluated.Gastric administration of EVOO, OA, and HT reduced the degree of lipid and protein oxidation, and increased glutathione peroxidase, making it a diet-based mechanism for enhancing protection against oxidative damage. In addition, it reduced the levels of LPS and LBP, which appeared as being increased in the EAE correlated with the oxidative stress produced by the disease.

Ripk3 regulates cardiac microvascular reperfusion injury: The role of IP3R-dependent calcium overload, XO-mediated oxidative stress and F-action/filopodia-based cellular migration

Ripk3-mediated cellular apoptosis is a major contributor to the pathogenesis of myocardial ischemia reperfusion (IR) injury. However, the mechanisms by which Ripk3 influences microvascular homeostasis and endothelial apoptosis are not completely understood. In this study, loss of Ripk3 inhibited endothelial apoptosis, alleviated luminal swelling, maintained microvasculature patency, reduced the expression of adhesion molecules and limited the myocardial inflammatory response. In vitro, Ripk3 deficiency protected endothelial cells from apoptosis and migratory arrest induced by HR injury. Mechanistically, Ripk3 had the ability to migrate onto the endoplasmic reticulum (ER), leading to ER damage, as evidenced by increased IP3R and XO expression. The higher IP3R content was associated with cellular calcium overload, and increased XO expression was involved in cellular oxidative injury. Furthermore, IP3R-mediated calcium overload and XO-dependent oxidative damage were able to initiate cellular apoptosis. More importantly, IP3R and XO also caused F-actin degradation into G-actin via post-transcriptional modification of cofilin, impairing the formation of the filopodia and limiting the migratory response of endothelial cells. Altogether, our data confirmed that Ripk3 was involved in microvascular IR injury via regulation of IP3R-mediated calcium overload, XO-dependent oxidative damage and filopodia-related cellular migration, ultimately leading to endothelial apoptosis and migratory inhibition. These findings provide a potential target for treating cardiac microcirculatory IR injury.

Lipophilic ester and amide derivatives of rosmarinic acid protect cells against H2O2-induced DNA damage and apoptosis: The potential role of intracellular accumulation and labile iron chelation

Phenolic acids represent abundant components contained in human diet. However, the negative charge in their carboxylic group limits their capacity to diffuse through biological membranes, thus hindering their access to cell interior. In order to promote the diffusion of rosmarinic acid through biological membranes, we synthesized several lipophilic ester- and amide-derivatives of this compound and evaluated their capacity to prevent H2O2-induced DNA damage and apoptosis in cultured human cells. Esterification of the carboxylic moiety with lipophilic groups strongly enhanced the capacity of rosmarinic acid to protect cells. On the other hand, the amide-derivatives were somewhat less effective but exerted less cytotoxicity at high concentrations. Cell uptake experiments, using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), illustrated different levels of intracellular accumulation among the ester- and amide-derivatives, with the first being more effectively accumulated, probably due to their extensive hydrolysis inside the cells. In conclusion, these results highlight the hitherto unrecognized fundamental importance of derivatization of diet-derived phenolic acids to unveil their biological potential.

Yap regulates gastric cancer survival and migration via SIRT1/Mfn2/mitophagy

Gastric cancer is the fifth most common cancer worldwide and Hippo-Yap is the novel signaling pathway which plays an important role in gastric cancer tumor development and progression. However, little insight is available to date regarding the specific role of Yes-associated protein (Yap) in gastric cancer. In the present study, we identified the mechanism through which Yap sustains gastric cancer viability and migration. Yap was greatly upregulated in gastric cancer cells and its expression promoted cellular migration and survival. Functional studies found that knockdown of Yap reduced the mitophagy activity, which subsequently caused mitochondrial apoptosis and cellular oxidative stress. The latter impaired adhesive protein expression, alleviated F-actin expression, blunted lamellipodium formation, leading to inhibition of cancer cell motility. Mechanistically, Yap preserved Sirtuin 1 (SIRT1) activity which manipulated mitofusin 2 (Mfn2) expression and subsequent mitophagy. Loss of Yap reduced SIRT1 expression and inhibited Mfn2-mediated mitophagy. Collectively, our results identified Hippo-Yap as a tumor promoter in gastric cancer that was mediated via activation of the SIRT1/Mfn2/mitophagy axis, with potential applications to gastric cancer therapy involving cancer survival and migration.