Free radical-scavenging properties of olive oil polyphenols

Oleuropein Relieves Pancreatic Ischemia Reperfusion Injury in Rats by Suppressing Inflammation and Oxidative Stress through HMGB1/NF-κB Pathway

Oleuropein (OLP) is a naturally occurring phenolic compound in olive plant with antioxidant and anti-inflammatory potential and can possibly be used in treating pancreatic injuries. This investigation aimed to follow the molecular mechanism behind the potential therapeutic effect of OLP against pancreatic injury persuaded by ischemia-reperfusion (I/R). Pancreatic I/R injury was induced by splenic artery occlusion for 60 min followed by reperfusion. Oral administration of OLP (10 and 20 mg/kg) for 2 days significantly alleviated I/R-persuaded oxidative damage and inflammatory responses in pancreatic tissue as indicated by the decreased malondialdehyde (MDA) content and increased glutathione peroxidase (GPx) activity, accompanied by the suppression of myeloperoxidase (MPO) activity and reduced levels of interleukin-1beta (IL-1β), nuclear factor kappa B (NF-κB), and tumor necrosis factor alpha (TNF-α) in pancreatic tissues. Furthermore, OLP treatment markedly restored the serum levels of amylase, trypsinogen-activated peptide (TAP), and lipase, with concurrent improvement in pancreatic histopathological alterations. Moreover, treatment with OLP regulated the pancreatic expression of inducible nitric oxide synthase (iNOS) and high-mobility group box 1 (HMGB1) relative to rats of the pancreatic IR group. Thus, OLP treatment significantly alleviates the I/R-induced pancreatic injury by inhibiting oxidative stress and inflammation in rats through downregulation of HMGB1 and its downstream NF-κB signaling pathway.

Pretreatment with oleuropein protects the neonatal brain from hypoxia-ischemia by inhibiting apoptosis and neuroinflammation

Hypoxic-ischemic (HI) encephalopathy is a cerebrovascular injury caused by oxygen deprivation to the brain and remains a major cause of neonatal mortality and morbidity worldwide. Therapeutic hypothermia is the current standard of care but it does not provide complete neuroprotection. Our aim was to investigate the neuroprotective effect of oleuropein (Ole) in a neonatal (seven-day-old) mouse model of HI. Ole, a secoiridoid found in olive leaves, has previously shown to reduce damage against cerebral and other ischemia/reperfusion injuries. Here, we administered Ole as a pretreatment prior to HI induction at 20 or 100 mg/kg. A week after HI, Ole significantly reduced the infarct area and the histological damage as well as white matter injury, by preserving myelination, microglial activation and the astroglial reactive response. Twenty-four hours after HI, Ole reduced the overexpression of caspase-3 and the proinflammatory cytokines IL-6 and TNF-α. Moreover, using UPLC-MS/MS we found that maternal supplementation with Ole during pregnancy and/or lactation led to the accumulation of its metabolite hydroxytyrosol in the brains of the offspring. Overall, our results indicate that pretreatment with Ole confers neuroprotection and can prevent HI-induced brain damage by modulating apoptosis and neuroinflammation.

Cardioprotective effect of oleuropein in a cisplatin-induced cardiotoxicity model in rats

This study investigated the cardioprotective effect of oleuropein against cisplatin-induced cardiac damage in terms of inflammatory, oxidative stress and cardiac parameters. In this study, 40 female Wistar albino rats were divided into four groups: control, cisplatin, oleuropein and cisplatin+oleuropein. To establish the experimental model, oleuropein (200 mg/kg) was administered for 14 days and cisplatin (7 mg/kg) was administered as a single dose on the seventh day. Cisplatin increased MDA cardiac parameters (CK, CK-MB and cTnI) and inflammatory cytokines (TNF-α, IL-1β and IL-6) in cardiac tissue and decreased GSH, GSH-Px and catalase levels. On the other hand, oleuropein improved cardiac parameters and decreased inflammatory cytokine and oxidative stress levels in cardiac tissue.

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.

Evaluation of the effects of hydroxytyrosol on human sperm parameters during cryopreservation

Human sperm cryopreservation is a routine procedure in assisted reproductive technology, but it has detrimental effects on different sperm parameters due to oxidative stress. Our objective was to assess the impacts of hydroxytyrosol (HT), as an antioxidant, on human sperm parameters following cryopreservation. In the first phase, 20 normal human semen samples were cryopreserved using the rapid freezing method with different concentrations of HT including 0, 50, 100, 150, and 200 μg/mL. In the second phase, 20 normal semen samples were collected and cryopreserved with 50 and 100 μg/mL HT. The beneficial effects of HT were determined by evaluation of motility (computer-assisted sperm analysis; CASA), viability (Eosin-nigrosine stain), DNA integrity (sperm chromatic dispersion test, SCD), reactive oxygen species (DCF and DHE staining by flowcytometry) lipid peroxidation (malondialdehyde, MDA test) and mitochondrial membrane potential (JC1 staining by flowcytometry) of sperm after cryopreservation. After thawing, sperm motility had an increasing trend in 50 and 100 μg/mL HT groups in comparison with other groups, althought the difference was not significant. However, sperm viability was significantly increased at 50 and 100 μg/mL HT. Our data also showed that sperm DNA fragmentation was significantly decreased after thawing at 100 μg/mL in comparison with 0 and 50 μg/mL HT. However, the level of intracellular reactive oxygen species, lipid peroxidation and mitochondrial membrane potential were not significantly different between groups. Our results showed that HT may have protective effects on the viability and DNA integrity of human sperm during the freezing-thawing process.

Drought-Adapted Mediterranean Diet Plants: A Source of Bioactive Molecules Able to Give Nutrigenomic Effects per sè or to Obtain Functional Foods

The Mediterranean diet features plant-based foods renowned for their health benefits derived from bioactive compounds. This review aims to provide an overview of the bioactive molecules present in some representative Mediterranean diet plants, examining their human nutrigenomic effects and health benefits as well as the environmental advantages and sustainability derived from their cultivation. Additionally, it explores the facilitation of producing fortified foods aided by soil and plant microbiota properties. Well-studied examples, such as extra virgin olive oil and citrus fruits, have demonstrated significant health advantages, including anti-cancer, anti-inflammatory, and neuroprotective effects. Other less renowned plants are presented in the scientific literature with their beneficial traits on human health highlighted. Prickly pear's indicaxanthin exhibits antioxidant properties and potential anticancer traits, while capers kaempferol and quercetin support cardiovascular health and prevent cancer. Oregano and thyme, containing terpenoids like carvacrol and γ-terpinene, exhibit antimicrobial effects. Besides their nutrigenomic effects, these plants thrive in arid environments, offering benefits associated with their cultivation. Their microbiota, particularly Plant Growth Promoting (PGP) microorganisms, enhance plant growth and stress tolerance, offering biotechnological opportunities for sustainable agriculture. In conclusion, leveraging plant microbiota could revolutionize agricultural practices and increase sustainability as climate change threatens biodiversity. These edible plant species may have crucial importance, not only as healthy products but also for increasing the sustainability of agricultural systems.

Olea europaea L-derived secoiridoids: Beneficial health effects and potential therapeutic approaches

Over the years, health challenges have become increasingly complex and global and, at the beginning of the 21st century, chronic diseases, including cardiovascular, neurological, and chronic respiratory diseases, as well as cancer and diabetes, have been identified by World Health Organization as one of the biggest threats to human health. Recently, antimicrobial resistance has also emerged as a growing problem of public health for the management of infectious diseases. In this scenario, the exploration of natural products as supplementation or alternative therapeutic options is acquiring great importance, and, among them, the olive tree, Olea europaea L, specifically leaves, fruits, and oil, has been increasingly investigated for its health promoting properties. Traditionally, these properties have been largely attributed to the high concentration of monounsaturated fatty acids, although, in recent years, beneficial effects have also been associated to other components, particularly polyphenols. Among them, the most interesting group is represented by Olea europaea L secoiridoids, comprising oleuropein, oleocanthal, oleacein, and ligstroside, which display anti-inflammatory, antioxidant, cardioprotective, neuroprotective and anticancer activities. This review provides an overview of the multiple health beneficial effects, the molecular mechanisms, and the potential applications of secoiridoids from Olea europaea L.

Olive Leaf Extract (OLE) as a Novel Antioxidant That Ameliorates the Inflammatory Response in Cystic Fibrosis

The deletion of phenylalanine at position 508 (F508del) produces a misfolded CFTR protein that is retained in the ER and degraded. The lack of normal CFTR channel activity is associated with chronic infection and inflammation which are the primary causes of declining lung function in Cystic Fibrosis (CF) patients. Moreover, LPS-dependent oxidative stress downregulates CFTR function in airway epithelial cells. Olive leaf extract (OLE) is used in traditional medicine for its effects, including anti-oxidant and anti-inflammatory ones. We found that OLE decreased the intracellular ROS levels in a dose-response manner in CFBE cells. Moreover, OLE attenuates the inflammatory response to LPS or IL-1β/TNFα stimulation, mimicking the infection and inflammatory status of CF patients, in CFBE and primary nasal epithelial (HNE) cells. Furthermore, we demonstrated that OLE restored the LPS-mediated decrease of TrikfaftaTM-dependent F508del-CFTR function in CFBE and HNE cultures. These findings provide strong evidence of OLE to prevent redox imbalance and inflammation that can cause chronic lung damage by enhancing the antioxidant activity and attenuating inflammation in CF airway epithelial cells. Additionally, OLE might be used in combination with CFTR modulators therapy to improve their efficacy in CF patients.

An Overview of Bioactive Phenolic Molecules and Antioxidant Properties of Beer: Emerging Trends

Beer is one of the oldest and most common beverages worldwide. The phenolic contents and antioxidant properties of beer are crucial factors in evaluating its nutritional quality. Special beers brewed with the addition of adjuncts are gaining in consumer preference, in response to demands for healthy food and new gustatory and olfactory stimuli. Many studies recently dealt with functional beers brewed with the addition of adjuncts. This review focuses on bioactive molecules, particularly the composition of phenolic compounds, and the antioxidant activity of beer. The current knowledge concerning the effect of the addition of adjuncts in the form of fruit, vegetables, herbs, and natural foods on the polyphenol content, antioxidant properties, and phenolic profile of beer is reviewed, with an outline of the emerging trends in brewing processes. Future studies need to complete the identification and characterization of the bioactive molecules in beer, as well as studying their absorption and metabolic fate in humans.

Exploring Olive Pomace for Skincare Applications: A Review

The cosmetic industry is continuously searching for new active ingredients in an effort to attend to consumer demands which, in recent years, are focused on more natural and environmentally friendly products, obtained from sustainable resources. Nevertheless, they are required to provide cosmetologically appealing skincare products, ultimately with the purpose of improving skin appearance. The olive oil industry generates a large amount of liquid and semi-solid by-products such as olive pomace. Their phytotoxicity impairs safe disposal, so valorization strategies that promote by-product reuse are needed, which may include skincare products. Hydroxytyrosol is the main phenolic compound present in olive pomace and possesses biological effects that make it a desirable active compound for cosmetic formulations such as antioxidant and anti-aging activities as well as photoprotector, depigmenting, antimicrobial and anti-inflammatory actions. Other compounds present in olive pomace can also have functional properties and skin-related benefits. However, the application of this by-product can be a challenge in terms of formulation’s design, stability, and proven efficacy, so appropriate methodologies should be used to validate its incorporation and may include extraction and further encapsulation of bioactive compounds in order to achieve effective and aesthetic appealing skincare products.

Hydroxytyrosol oleate: A promising neuroprotective nanocarrier delivery system of oleuropein and derivatives

Olive Phenols (OPs) are known to be potent antioxidants and possess various bioactivities and health benefits. Epidemiological studies suggested that consumption of olive oil reduces the risk of different diseases exerting a protective effect against certain malignant tumors (prostate, breast, digestive tract, endothelium, etc.). However, extremely low absorption rate of olive phenolic compounds restricts their bioactivity. In this context, solid lipid nanoparticles (SLNs) are a promising solution because they provide higher drug stability and can incorporate both lipophilic and hydrophilic drugs. Interesting experimental results have been obtained using hydroxytyrosol oleate (HtyOle) as a main component of a nanoparticle delivery system containing oleuropein (OL), oleuropein aglycone (3,4-DHPEA-EA), or hydroxytyrosol itself (Hty). In this work, hydroxytyrosol oleate (HtyOle) and hydroxytyrosol oleate (HtyOle)-based solid lipid nanoparticles were prepared and characterized. In addition, we evaluatedin vitro their antioxidant activity by DPPH assays and by ROS formation using the SH-SY5Y cell line.

Enhancement of Lipid Stability and Acceptability of Canned Seafood by Addition of Natural Antioxidant Compounds to the Packing Medium-A Review

Seafoods are known to include high contents of valuable constituents. However, they are reported to be highly perishable products, whose quality rapidly declines post-mortem, thus demanding efficient processing and storage. Among the traditional technologies, canning represents one of the most important means of marine species preservation. However, owing to the thermal sensitivity of the chemical constituents of marine species, remarkable degradative mechanisms can be produced and lead to important quality losses. The demand for better quality food makes the need for advanced preservation techniques a topic to be addressed continually in the case of seafood. One such strategy is the employment of preservative compounds obtained from natural resources. The current review provides an overview of the research carried out concerning the effect of the addition of bioactive compounds to the packing medium on the thermal stability of canned seafood. This review addresses the preservative effect of polyphenol-rich oils (i.e., extra virgin olive oil) and different kinds of products or extracts obtained from plants, algae and seafood by-products. In agreement with the great incidence of lipid damage on the nutritional and acceptability values during high-temperature seafood processing, this work is especially focussed on the inhibitory effect of lipid oxidation development.

The Impact of a Natural Olive-Derived Phytocomplex (OliPhenolia®) on Exercise-Induced Oxidative Stress in Healthy Adults

The role of natural polyphenols in reducing oxidative stress and/or supporting antioxidant mechanisms, particularly relating to exercise, is of high interest. The aim of this study was to investigate OliPhenolia® (OliP), a biodynamic and organic olive fruit water phytocomplex, rich in hydroxytyrosol (HT), for the first time within an exercise domain. HT bioavailability from OliP was assessed in fifteen healthy volunteers in a randomized, double-blind, placebo controlled cross-over design (age: 30 ± 2 yrs; body mass: 76.7 ± 3.9 kg; height: 1.77 ± 0.02 m), followed by a separate randomized, double-blinded, cohort trial investigating the short-term impact of OliP consumption (2 × 28 mL∙d−1 of OliP or placebo (PL) for 16-days) on markers of oxidative stress in twenty-nine recreationally active participants (42 ± 2 yrs; 71.1 ± 2.1 kg; 1.76 ± 0.02 m). In response to a single 28 mL OliP bolus, plasma HT peaked at 1 h (38.31 ± 4.76 ng∙mL−1), remaining significantly elevated (p < 0.001) until 4 h. Plasma malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and HT were assessed at rest and immediately following exercise (50 min at ~75% V˙O2max then 10 min intermittent efforts) and at 1 and 24 h post-exercise, before and after the 16-day supplementation protocol. Plasma HT under resting conditions was not detected pre-intervention, but increased to 6.3 ± 1.6 ng·mL−1 following OliP only (p < 0.001). OliP demonstrated modest antioxidant effects based on reduced SOD activity post-exercise (p = 0.016) and at 24 h (p ≤ 0.046), and increased GSH immediately post-exercise (p = 0.009) compared with PL. No differences were reported for MDA and CAT activity in response to the exercise protocol between conditions. The phenolic compounds within OliP, including HT, may have specific antioxidant benefits supporting acute exercise recovery. Further research is warranted to explore the impact of OliP following longer-term exercise training, and clinical domains pertinent to reduced oxidative stress.

Multifaceted role of polyphenols in the treatment and management of neurodegenerative diseases

Neurodegenerative diseases (NDDs) are conditions that cause neuron structure and/or function to deteriorate over time. Genetic alterations may be responsible for several NDDs. However, a multitude of physiological systems can trigger neurodegeneration. Several NDDs, such as Huntington's, Parkinson's, and Alzheimer's, are assigned to oxidative stress (OS). Low concentrations of reactive oxygen and nitrogen species are crucial for maintaining normal brain activities, as their increasing concentrations can promote neural apoptosis. OS-mediated neurodegeneration has been linked to several factors, including notable dysfunction of mitochondria, excitotoxicity, and Ca²⁺ stress. However, synthetic drugs are commonly utilized to treat most NDDs, and these treatments have been known to have side effects during treatment. According to providing empirical evidence, studies have discovered many occurring natural components in plants used to treat NDDs. Polyphenols are often safer and have lesser side effects. As, epigallocatechin-3-gallate, resveratrol, curcumin, quercetin, celastrol, berberine, genistein, and luteolin have p-values less than 0.05, so they are typically considered to be statistically significant. These polyphenols could be a choice of interest as therapeutics for NDDs. This review highlighted to discusses the putative effectiveness of polyphenols against the most prevalent NDDs.

Effects of intestinal bacteria on cardiovascular disease

In the long process of human evolution, the Intestinal Bacteria has become intimately related to human health, producing many metabolites in the intestines that can affect cardiovascular disease. Today, the incidence of cardiovascular disease is rising, its treatment is becoming increasingly important, and new therapeutic targets are needed. Here we describe the effects of trimethylamine oxide (TMAO), lipid metabolism, phenolic compounds, indole sulfate (IS), oleuropein (OL), and hydroxytyrosol (HT) on atherosclerosis, heart failure, hypertension, and other cardiovascular diseases, as well as their mechanism of action. This study provides new ideas, new methods, and new directions for the treatment of cardiovascular disease.

Valorization of an Underutilized Waste from Olive Oil Production by Recovery of Hydroxytyrosol

Hydroxytyrosol (HT) is one of the most powerful natural antioxidants, mainly contained in olive oil and its by-products. Here, a procedure for the preparation of an HT-enriched sample is described. An acidic aqueous extract (pH 1.25) from Olive Oil Dregs (OOD), a by-product from oil mills, was prepared by incubation at 37 °C for 1 h. The total phenolic content and HT amount were 6.24 ± 0.10 mg gallic acid equivalent/g OOD and 532.98 ± 5.78 μg/g OOD, respectively. Amberlite XAD16N and XAD7HP resins were used for the recovery of HT from the raw extract. Several elution conditions were tested with both resins, and elution with 25% ethanol provided the highest HT recovery (92.50% from XAD7HP). Antioxidant activities were assessed in the pool containing the highest quantity of HT. The results were compared with those of the raw extract. Ferric reducing antioxidant power values were comparable (95.71 ± 2.50 and 96.64 ± 13.47 μg ascorbic acid equivalent/mg for HT-enriched pool and raw extract, respectively), while the radical scavenging activity was higher for the pool (92.83% ± 0.44 and 44.12% ± 1.82, respectively). The results reported here demonstrate that HT can be recovered with a high yield from OOD, providing a preparation with high radical scavenging power. In addition, it is proved that this by-product, poorly considered up to now, can be usefully exploited.

Dietary olive oil intake aggravates psoriatic skin inflammation in mice via Nrf2 activation and polyunsaturated fatty acid imbalance

Psoriasis is a chronic inflammatory skin disease, which does not have effective treatment options. However, olive oil has been suggested as an alternative to treat psoriasis, but no study has evaluated the mechanisms involved in the effects of olive oil on psoriasis. Thus, the current study investigated whether olive oil could ameliorate psoriasiform skin inflammation. To test this, mice received topical application of imiquimod to induce inflammation and were treated orally with olive oil. Human immortalized keratinocytes were also treated with imiquimod and olive oil. Epidermal thickness and keratinocyte proliferation were increased in imiquimod-induced lesions of olive-oil-treated animals. In both in vitro and in vivo studies, protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) were elevated following imiquimod and olive oil administration. Inhibition of Nrf2 abolished the increased proliferation of keratinocytes treated with imiquimod and olive oil, demonstrating the role of Nrf2 in olive oil-mediated exacerbation of psoriasiform skin inflammation. In addition, lower levels of linoleic acid and higher levels of oleic acid were observed in imiquimod- and olive-oil-treated animals, which may also contribute to the adverse effects of olive oil on psoriasis. In conclusion, dietary intake of olive oil aggravates the symptoms of psoriatic skin lesions through the overexpression of Nrf2 and an imbalance in oleic and linoleic acids levels, suggesting that a diet rich in olive oil may have significant negative effects on psoriasis.

Nutraceutical Role of Polyphenols and Triterpenes Present in the Extracts of Fruits and Leaves of Olea europaea as Antioxidants, Anti-Infectives and Anticancer Agents on Healthy Growth

There is currently a worldwide consensus and recognition of the undoubted health benefits of the so-called Mediterranean diet, with its intake being associated with a lower risk of mortality. The most important characteristics of this type of diet are based on the consumption of significant amounts of fruit, vegetables, legumes, and nuts, which provide, in addition to some active ingredients, fiber and a proportion of vegetable protein, together with extra virgin olive oil (EVOO) as the main sources of vegetable fat. Fish and meat from poultry and other small farm animals are the main sources of protein. One of the main components, as already mentioned, is EVOO, which is rich in monounsaturated fatty acids and to a lesser extent in polyunsaturated fatty acids. The intake of this type of nutrient also provides an important set of phytochemicals whose health potential is widely spread and agreed upon. These phytochemicals include significant amounts of anthocyanins, stilbenes, flavonoids, phenolic acids, and terpenes of varying complexities. Therefore, the inclusion in the diet of this type of molecules, with a proven healthy effect, provides an unquestionable preventive and/or curative activity on an important group of pathologies related to cardiovascular, infectious, and cancerous diseases, as well as those related to the metabolic syndrome. The aim of this review is therefore to shed light on the nutraceutical role of two of the main phytochemicals present in Olea europaea fruit and leaf extracts, polyphenols, and triterpenes, on healthy animal growth. Their immunomodulatory, anti-infective, antioxidant, anti-aging, and anti-carcinogenic capabilities show them to be potential nutraceuticals, providing healthy growth.

Anti-Inflammatory Effects Induced by a Polyphenolic Granular Complex from Olive (Olea europaea, Mainly Cultivar coratina): Results from In Vivo and Ex Vivo Studies in a Model of Inflammation and MIA-Induced Osteoarthritis

MOMAST^® GR25 is a polyphenolic granular complex from olive pressing juice with high total content in polyphenols. In this work, we evaluated the possible anti-inflammatory effects of MOMAST^® GR25 in both acute and chronic inflammatory models. MOMAST^® GR25 decreased the levels of prostaglandin (PG) E₂ and 8-iso-PGF_2α in isolated rat colon, liver, and heart specimens stimulated with lipopolysaccharide (LPS). In vivo, compared to controls, rats treated with MOMAST^® GR25 (100 mg/kg to 1 g/kg) showed a significant reduction in both licking/biting time in the formalin test. In a rat model of osteoarthritis by monoiodoacetate (MIA) injection, MOMAST^® GR25 showed pain-relieving properties when acutely administered, reducing mechanical hyperalgesia and spontaneous pain. Moreover, a repeated daily treatment with MOMAST^® GR25 (300 mg/kg) fully counteracted osteoarticular pain without the development of tolerance to the antinociceptive effect. Taken together, our present findings showed that MOMAST^® GR25 could represent a potential strategy for the treatment of inflammation and pain.

XENOHORMESIS UNDERLYES THE ANTI-AGING AND HEALTHY PROPERTIES OF OLIVE POLYPHENOLS

The paper provides a comprehensive and foundational mechanistic framework of hormesis that establishes its centrality in medicine and public health. This hormetic framework is applied to the assessment of olive polyphenols with respect to their capacity to slow the onset and reduce the magnitude of a wide range of age-related disorders and neurodegenerative diseases, including Alzheimer's Disease and Parkinson's Disease. It is proposed that olive polyphenol-induced anti-inflammatory protective effects are mediated in large part via the activation of AMPK and the upregulation of Nrf2 pathway. Consistently, herein we also review the importance of the modulation of Nrf2-related stress responsive vitagenes by olive polyphenols, which at low concentration according to the hormesis theory activates this neuroprotective cascade to preserve brain health and its potential use in the prevention and therapy against aging and age-related cognitive disorders in humans.

Synergistic Effect of Squalene and Hydroxytyrosol on Highly Invasive MDA-MB-231 Breast Cancer Cells

Several studies relate Mediterranean diet and virgin olive oil (VOO) intake with lower risk of several chronic diseases, including breast cancer. Many of them described antitumor properties of isolated minor compounds present in VOO, but beneficial properties of VOO arise from the effects of all its compounds acting together. The aim of the present study was to test the antitumor effects of two minor compounds from VOO (hydroxytyrosol (HT) and squalene (SQ)) on highly metastatic human breast tumor cells (MDA-MB-231) when acting in combination. Both isolated compounds were previously analyzed without showing any antitumoral effect on highly invasive MDA-MB-231 breast cancer cells, but the present results show that HT at 100 µM, combined with different concentrations of SQ, could exert antitumor effects. When they are combined, HT and SQ are able to inhibit cell proliferation, promoting apoptosis and DNA damage in metastatic breast cancer cells. Therefore, our results suggest that the health-promoting properties of VOO may be due, at least in part, to the combined action of these two minor compounds.

Herbal Oils for Treatment of Chronic and Diabetic Wounds: A Systematic Review

BACKGROUND

In the present scenario, diabetes is a growing health challenge, and its occurrence is growing across the globe. Diabetes, with its complications like diabetic wounds, vasculopathy, neuropathy, wound infections, and oxidative stress, is a serious cause of mortality worldwide.

INTRODUCTION

Among the various complications, treatment of diabetic foot and ulcers is one of the major concerns in patients who are suffering from diabetes. The causative factors for this condition include increased oxidative stress, high blood glucose levels, vascular insufficiency, and microbial infections, and many a time, if left untreated, it may even lead to amputations of the lower extremities. The present therapy for the treatment of diabetic wounds mainly involves the use of synthetic moieties and other biotechnology-derived biomolecules, including growth factors. Few plant products are also useful in the treatment of wounds.

METHODS

Essential oils derived from various herbs are reported to possess significant wound healing potential and promote blood clotting, help to fight infections, and accelerate the wound healing process. Hence, the present review is a systematic analysis of all the available data on the use of the natural oils with their biological source, active phytochemical constituents present, and the probable mechanism of action for the treatment of chronic and diabetic wounds in suitable animal models. A methodical collection of data was performed, and information was searched up to April 2020 in entirety. Key phrases used for the data search include the pathophysiology of wounds, diabetic foot wound and its complications, natural oils for chronic and diabetic wound treatment.

RESULTS

This review summarizes the natural oils which are reported in the literature to be beneficial in the treatment of chronic wounds, while some oils have been specifically also studied against wounds in diabetic rats. Essential oils are said to interact with the body pharmacologically, physiologically and psychologically and help in rapid wound healing. However, the majority of the literature studies have demonstrated wound healing activity only in animal models (preclinical data), and further clinical studies are necessary.

CONCLUSION

This review provides a platform for further studies on the effective utilization of natural oils in the treatment of chronic and diabetic wounds, especially if oils are to receive credibility in the management of chronic wounds.

Multielement Characterization and Antioxidant Activity of Italian Extra-Virgin Olive Oils

Food product safety and quality are closely related to the elemental composition of food. This study combined multielement analysis and chemometric tools to characterize 237 extra-virgin olive oil (EVOO) samples from 15 regions of Italy, and to verify the possibility of discriminating them according to different quality factors, such as varietal or geographical origin or whether they were organically or traditionally produced. Some elements have antioxidant properties, while others are toxic to humans or can promote oxidative degradation of EVOO samples. In particular, the antioxidant activity of oils’ hydrophilic fraction was estimated and the concentrations of 45 elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). At first, univariate and multivariate analyses of variance were used to compare the element concentrations, and statistically significant differences were found among samples from different regions. Successively, discriminant classification approaches were used to build a model for EVOO authentication, considering, in turn, various possible categorizations. The results have indicated that chemometric methods coupled with ICP-MS have the potential to discriminate and characterize the different types of EVOO, and to provide “typical” elemental fingerprints of the various categories of samples.

Ethanol Extract of Myrtle (Myrtus communis L.) Berries as a Remedy for Streptozotocin-Induced Oxidative Stress in Rats

Streptozotocin (STZ) is an antitumor antibiotic indicating in the treatment of metastatic islet cell carcinoma of the pancreas. It is also used as a tool to create experimental diabetes models. The STZ exposure at a high dose causes severe damage to cells of humans and other mammals. The goal of the present study was to assess the protective effects of the ethanol extract of the Myrtle (Myrtus communis L.) berries, which is a well-known medicinal plant due to its rich phenolic content and beneficial effects on health, against STZ-induced oxidative stress in the diabetic rats.Diabetes was induced by STZ (40 mg/kg, i.p.) in the rats. After diabetes induction, a significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and blood glucose levels as well as a significant decrease in superoxide dismutase (SOD) activities and glutathione (GSH) levels was observed. The rats were treated to three different ethanol extracts of Myrtle berries (0.25, 0.5, and 1 g/kg) by oral gavage for 14 days. At the end of the experiment, ALT, AST, MDA, and blood glucose levels of the rats significantly decreased while significant increases in GSH levels and SOD activities were observed.We believe that our findings may contribute to the development of new drugs in the treatment of many global disorders due to the antioxidant activity of the ethanol extract of Myrtus communis L. berries.

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.

Antioxidant Effect of Hydroxytyrosol, Hydroxytyrosol Acetate and Nitrohydroxytyrosol in a Rat MPP+ Model of Parkinson's Disease

3,4-Dihydroxyphenyl ethanol, known as hydroxytyrosol (HTy), is a phenylpropanoid found in diverse vegetable species. Several studies have demonstrated that HTy is a potent antioxidant. Thus, our study is aimed to evaluate the antioxidant effect of HTy and its derivatives, hydroxytyrosol acetate (HTyA) and nitrohydroxytyrosol (HTyN), in a model of oxidative stress induced by 1-methyl-4-phenylpyridinium (MPP⁺) in rats. Rats were administered intravenously (i.v.) in the tail with 1 mL saline solution or polyphenol compound (1.5 mg/kg) 5 min before intrastriatal infusion of 10 µg MPP⁺/8 µL. We found that rats injured with MPP⁺, pretreatment with HTy, HTyA or HTyN significantly decreased ipsilateral turns. This result was consistent with a significant preservation of striatal dopamine levels and decreased lipid fluorescence products (LFP), a marker of oxidative stress. Brain GSH/GSSG ratio, from rats pretreated with HTy or HTyN showed a significant preservation of that marker, decreased as a consequence of MPP⁺-induced oxidative damage. These results show an antioxidant effect of HTy, HTyA and HTyN in the MPP⁺ model of Parkinson's disease in the rat.

Olive Polyphenols: Antioxidant and Anti-Inflammatory Properties

Oxidative stress and inflammation triggered by increased oxidative stress are the cause of many chronic diseases. The lack of anti-inflammatory drugs without side-effects has stimulated the search for new active substances. Plant-derived compounds provide new potential anti-inflammatory and antioxidant molecules. Natural products are structurally optimized by evolution to serve particular biological functions, including the regulation of endogenous defense mechanisms and interaction with other organisms. This property explains their relevance for infectious diseases and cancer. Recently, among the various natural substances, polyphenols from extra virgin olive oil (EVOO), an important element of the Mediterranean diet, have aroused growing interest. Extensive studies have shown the potent therapeutic effects of these bioactive molecules against a series of chronic diseases, such as cardiovascular diseases, diabetes, neurodegenerative disorders and cancer. This review begins from the chemical structure, abundance and bioavailability of the main EVOO polyphenols to highlight the effects and the possible molecular mechanism(s) of action of these compounds against inflammation and oxidation, in vitro and in vivo. In addition, the mechanisms of inhibition of molecular signaling pathways activated by oxidative stress by EVOO polyphenols are discussed, together with their possible roles in inflammation-mediated chronic disorders, also taking into account meta-analysis of population studies and clinical trials.

Olive Oil Dregs as a Novel Source of Natural Antioxidants: Extraction Optimization towards a Sustainable Process

Olive oil dregs (OOD), which are an underutilized by-product from oil mills, were used for the extraction of antioxidant compounds. The residues from three oil mills located in Campania (Southern Italy) were extracted with acidified methanol, and hydroxytyrosol (HT) was the main phenolic compound detected. Total phenolic content (TPC) and HT amount were measured. EVO Campania oil mill provided the residue with the highest TPC and HT quantities: 6.801 ± 0.159 mg Gallic Acid Equivalents (GAE)/g OOD and 519.865 ± 9.082 μg/g OOD, respectively. Eco-friendly extractions at different temperatures and times were performed on EVO Campania OOD, obtaining 9.122 ± 0.104 mg GAE/g OOD and 541.330 ± 64.087 μg/g OOD for TPC and HT, respectively, at 121 °C for 60 min. Radical Scavenging Activity (RSA), Superoxide Scavenging Activity (SSA), and Ferric Reducing Antioxidant Power (FRAP) were measured in OOD aqueous extracts. Extract prepared at 37 °C for 60 min showed the greatest RSA and SSA values (44.12 ± 1.82 and 75.72 ± 1.78, respectively), whereas extract prepared at 121 °C for 60 min exhibited the highest FRAP value (129.10 ± 10.49 μg Ascorbic Acid Equivalents (AAE)/mg). OOD extracts were able to protect sunflower oil from oxidation for 4 weeks at 65 °C. The overall results suggest that this novel residue can be usefully valorized by providing HT-rich extracts to use as antioxidant agents.

Concentration of Bioactive Phenolic Compounds in Olive Mill Wastewater by Direct Contact Membrane Distillation

Olive mill wastewater (OMW), generated as a by-product of olive oil production, is considered one of the most polluting effluents produced by the agro-food industry, due to its high concentration of organic matter and nutrients. However, OMW is rich in several polyphenols, representing compounds with remarkable biological properties. This study aimed to analyze the chemical profile as well as the antioxidant and anti-obesity properties of concentrated fractions obtained from microfiltered OMW treated by direct contact membrane distillation (DCMD). Ultra-high performance liquid chromatography (UHPLC) analyses were applied to quantify some phenols selected as phytochemical markers. Moreover, α-Amylase, α-glucosidase, and lipase inhibitory activity were investigated together with the antioxidant activity by means of assays, namely β-carotene bleaching, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) diammonium salts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and Ferric Reducing Activity Power (FRAP) tests. MD retentate—which has content of about five times greater of hydroxytyrosol and verbascoside and about 7 times greater of oleuropein than the feed—was more active as an antioxidant in all applied assays. Of interest is the result obtained in the DPPH test (an inhibitory concentration 50% (IC₅₀) of 9.8 μg/mL in comparison to the feed (IC₅₀ of 97.2 μg/mL)) and in the ABTS assay (an IC₅₀ of 0.4 μg/mL in comparison to the feed (IC₅₀ of 1.2 μg/mL)).

Keratinocytes Migration Promotion, Proliferation Induction, and Free Radical Injury Prevention by 3-Hydroxytirosol

3-hydroxytyrosol (HT) is the main phenolic compound found in olive oil with known antioxidant, anti-inflammatory, and antimicrobial properties in several dermatological conditions, both when taken in the form of olive oil or pure in cosmeceutical formulations. To date, its direct effect on the wound healing process and the molecular mechanisms involved have not yet been elucidated. Thus, in the present study, we aimed to explore its effects in vitro in epidermal keratinocyte cultures focusing on the molecular mechanism implied. HT was able to induce keratinocyte proliferation in the low micromolar range, increasing the expression of cyclin dependent kinases fundamental for cell cycle progression such as CDK2 and CDK6. Furthermore, it increased cell migration through the activation of tissue remodeling factors such as matrix metalloproteinase-9 (MMP-9) protein. Then, we evaluated whether HT also showed antioxidant activity at this concentration range, protecting from H₂O₂-induced cytotoxicity. The HT prevented the activation of ATM serine/threonine kinase (ATM), Checkpoint kinase 1 (Chk1), Checkpoint kinase 2 (Chk2), and p53, reducing the number of apoptotic cells. Our study highlighted novel pharmacological properties of HT, providing the first evidence of its capability to induce keratinocyte migration and proliferation required for healing processes and re-epithelialization.

Enhanced full-thickness wound healing via Sophora gibbosa extract delivery based on a chitosan/gelatin dressing incorporating microemulsion

There are many synthetic drugs in literature have been utilized in healing of the wounds although the natural product specially antioxidants can offer similar if not better biological activity in that regard. Genus Sophora is well known to contain flavonoids and phenolic compounds which have antioxidant and inflammatory effects. So, the aim of the current study was to develop and evaluate chitosan/gelatin based Sophora gibbosa extract-loaded microemulsion as wound dressing. Sophora gibbosa extract (SGE) contained 16 major compounds which have reasonable antioxidant activity. The developed microemulsion showed that Tween 80 produced significant (p < 0.05) lower particle size than Pluronic F127 at the same SGE concentration whereas high concentration of extract results in large particle size. Thermodynamic stability studies showed that using higher concentration of the extract produced less stable formulations. The selected formulation was impregnated in the dressing base (chitosan/gelatin; 2:1 w/w ratio) which exhibited more water absorption. In vivo evaluation revealed that the dressing displayed superior wound repair compared to the control in terms histological examination and determination of alpha smooth muscle actin (α-SMA) and proliferating cell nuclear antigen (PCNA). Thus, SGE-loaded microemulsion-impregnated gelatin/chitosan could be a potential candidate for the wound healing.

Antioxidant Efficacy of Olive By-Product Extracts in Human Colon HCT8 Cells

The production of olive oil is accompanied by the generation of a huge amount of waste and by-products including olive leaves, pomace, and wastewater. The latter represents a relevant environmental issue because they contain certain phytotoxic compounds that may need specific treatments before the expensive disposal. Therefore, reducing waste biomass and valorizing by-products would make olive oil production more sustainable. Here, we explore the biological actions of extracts deriving from olive by-products including olive pomace (OP), olive wastewater (OWW), and olive leaf (OLs) in human colorectal carcinoma HCT8 cells. Interestingly, with the same phenolic concentration, the extract obtained from the OWW showed higher antioxidant ability compared with the extracts derived from OP and OLs. These biological effects may be related to the differential phenolic composition of the extracts, as OWW extract contains the highest amount of hydroxytyrosol and tyrosol that are potent antioxidant compounds. Furthermore, OP extract that contains a higher level of vanillic acid than the other extracts displayed a cytotoxic action at the highest concentration. Together these findings revealed that phenols in the by-product extracts may interfere with signaling molecules that cross-link several intracellular pathways, raising the possibility to use them for beneficial health effects.

Gender differences in the antioxidant response of oral administration of hydroxytyrosol and oleuropein against N-ethyl-N-nitrosourea (ENU)-induced glioma

Brain tumorigenesis has been associated not only with oxidative stress, but also with a reduced response of non-enzyme and enzyme antioxidant defense systems. In fact, the imbalance between free-radical production and the efficiency of the antioxidant defense systems triggers the process because the central nervous system (CNS) is very sensitive to free-radical damage. Phenolic compounds, mainly oleuropein and its major metabolite hydroxytyrosol, derived from olives and virgin olive oil, have been shown to exert important anticancer activities both in vitro and in vivo due to their antioxidant properties. The present study analyzes the effects of the oral administration of oleuropein, hydroxytyrosol and the mixture of both phenolic compounds in rats with transplacental N-ethyl-N-nitrosourea (ENU)-induced brain tumors to analyze their potential effect against brain tumorigenesis through the modification of redox system components. Oxidative stress parameters, non-enzyme and enzyme antioxidant defense systems and blood chemistry were assayed in the different experimental groups. The treatment with oleuropein, hydroxytyrosol and/or the mixture of both phenolic compounds promotes a limited beneficial effect as anticancer compounds in our ENU-induced animal model of brain tumor. These effects occur via redox control mechanisms involving endogenous enzymatic and non-enzymatic antioxidant defense systems, and are highly dependent on the gender of the animals.

Semi-synthesis as a tool for broadening the health applications of bioactive olive secoiridoids: a critical review

Covering: 2005 up to 2020Olive bioactive secoiridoids are recognized as natural antioxidants with multiple beneficial effects on human health. Nevertheless, the study of their biological activity has also disclosed some critical aspects associated with their application. Firstly, only a few of them can be extracted in large amounts from their natural matrix, namely olive leaves, drupes, oil and olive mill wastewater. Secondly, their application as preventive agents and drugs is limited by their low membrane permeability. Thirdly, the study of their biological fate after administration is complicated by the absence of pure analytical standards. Accordingly, efficient synthetic methods to obtain natural and non-natural bioactive phenol derivatives have been developed. Among them, semi-synthetic protocols represent efficient and economical alternatives to total synthesis, combining efficient extraction protocols with efficient catalytic conversions to achieve reasonable amounts of active molecules. The aim of this review is to summarize the semi-synthetic protocols published in the last fifteen years, covering 2005 up to 2020, which can produce natural olive bioactive phenols scarcely available by extractive procedures, and new biophenol derivatives with enhanced biological activity. Moreover, the semi-synthetic protocols to produce olive bioactive phenol derivatives as analytical standards are also discussed. A critical analysis of the advantages offered by semi-synthesis compared to classical extraction methods or total synthesis protocols is also performed.

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.

Do nutrients and other bioactive molecules from foods have anything to say in the treatment against COVID-19?

The repositioning of therapeutic agents already approved by the regulatory agencies for the use of drugs is very interesting due to the immediacy of their use; similarly, the possibility of using molecules derived from foods, whether nutrients or not, is of great importance, also because of their immediate therapeutic applicability. Candidates for these natural therapies against COVID-19 should show certain effects, such as restoring mitochondrial function and cellular redox balance. This would allow reducing the susceptibility of risk groups and the cascade of events after SARS-CoV-2 infection, responsible for the clinical picture, triggered by the imbalance towards oxidation, inflammation, and cytokine storm. Possible strategies to follow through the use of substances of food origin would include: a) the promotion of mitophagy to remove dysfunctional mitochondria originating from free radicals, proton imbalance and virus evasion of the immune system; b) the administration of transition metals whose redox activity would lead to their own oxidation and the consequent generation of a reduced environment, which would normalize the oxidative state and the intracellular pH; c) the administration of molecules with demonstrated antioxidant capacity; d) the administration of compounds with anti-inflammatory and vasodilatory activity; e) the administration of immunomodulatory compounds.

Dietary Fatty Acid Factors in Alzheimer's Disease: A Review

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by brain function disorder and chronic cognitive function impairment. The onset of AD is complex and is mostly attributed to interactions between genetic factors and environmental factors. Lifestyle, dietary habits, and food consumption are likely to play indispensable functions in aged-related neurodegenerative diseases in elderly people. An increasing number of epidemiological studies have linked dietary fatty acid factors to AD, raising the point of view that fatty acid metabolism plays an important role in AD initiation and progression as well as in other central nervous system disorders. In this paper, we review the effects of the consumption of various dietary fatty acids on AD onset and progression and discuss the detrimental and beneficial effects of some typical fatty acids derived from dietary patterns on the pathology of AD. We outline these recent advances, and we recommend that healthy dietary lifestyles may contribute to preventing the occurrence and decreasing the pathology of AD.

Food-derived antioxidants and COVID-19

SARS-CoV-2 (previously 2019-nCoV), the pathogenic agent of COVID-19 disease, started to expand from Wuhan, China, on December 2019 and in 2 months, it spread worldwide giving origin to a pandemic. COVID-19 has a stronger transmission capacity by inhalation of infectious aerosols and after an incubation time of 3-14 days, it may be responsible for diseases ranging from the asymptomatic to fatal consequences. COVID-19 has emerged as a multifaceted, multisystem, multi-organ disorder, which produces its pathogenic effects through a quite ubiquitous target at the level of multiple organs and in which oxidative stress and inflammatory process play relevant roles. Thus, besides the development of a pharmacological therapy, in the field of alternative and coadjutant therapeutic, the use of dietary supplements or nutraceuticals for the prevention or treatment of SARS-CoV-2 infection may be a useful strategy. Herein, we specifically comment on some literature evidences, which link the food-derived antioxidants and metal-chelating agents with treatment and prevention of oxidative stress and inflammation that play a key role in the progression of COVID-19. PRACTICAL APPLICATIONS: Oxidative stress and inflammation are key factors increasing COVID-19 severity especially in the presence of chronic diseases associated with the antioxidant system fragility. These evidences support the recommendation of antioxidants supplementation as useful strategies against COVID-19. In light with these observations, herein, a comment which describes the major antioxidants and metal-chelating agents from food sources that might be useful for the treatment and prevention of oxidative stress and inflammation during COVID-19.

Drought stress improved the capacity of Rhizophagus irregularis for inducing the accumulation of oleuropein and mannitol in olive (Olea europaea) roots

Olive trees are often subjected to a prolonged dry season with low water availability, which induces oxidative stress. Arbuscular mycorrhizal (AM) symbioses can improve olive plant tolerance to water deficit. This study investigated several aspects related to drought tolerance in AM fungi olive plants. Non-AM and AM plants were grown under well-watered or drought-stressed conditions, and mycorrhizal growth response, neutral lipid fatty acid (NLFA)16:1ω5 and phospholipid fatty acid (PLFA) 16:1ω5 in roots (intraradical mycelium) and in soil (extraradical mycelium), carbohydrates (monosaccharides, disaccharides and polyols) and phenolic compounds (phenolic alcohols, flavonoids, lignans, secoiridoids and hydroxycinnamic acid derivatives) were determined. Results showed that the amounts of PLFA 16:1ω5 and NLFA 16:1ω5 were significantly influenced by drought stress conditions. The NLFA 16:1ω5/PLFA 16:1ω5 ratio showed a dramatic decrease (-62%) with the application of water deficit stress, indicating that AM fungi allocated low carbon to storage structures under stress conditions. Mannitol and verbascoside are the main compounds detected in the roots of well-watered plants, whereas oleuropein and mannitol are the main compounds differentially accumulated in the roots of water-stressed plants. The oleuropein/verbascoside ratio increased in the case of drought-stressed AM plants by 30%, while the mannitol/oleuropein ratio was decreased by 46%, when compared to the non-AM stressed plants. Mycorrhization therefore oriented the flux toward the biosynthetic pathway of oleuropein and the data suggest that sugar and phenolic compound metabolism may have been redirected to the formation of oleuropein in roots of AM stressed plants, that may underlie their enhanced tolerance to drought stress.

Effects of Hydroxytyrosol on Expression of Apoptotic Genes and Activity of Antioxidant Enzymes in LS180 Cells

Purpose

Colorectal cancer is the third–most commonly occurring cancer in developed countries. Hydroxytyrosol is a potent antioxidant that has several activities, such as oxidative-stress control, inhibition of cell proliferation, and induction of apoptosis. In this study, the effect of hydroxytyrosol on the expression of genes effective in apoptosis — BAX, BCL2, CASP3, P53, PPARG, and NFE2L2 — and antioxidant-enzyme activity in LS180 cells of human colorectal cancer was investigated.

Methods

The human colorectal cancer cell line LS180 was treated with different concentrations of hydroxytyrosol for 24 hours. Expression of BAX, BCL2, CASP3, NFE2L2, PPARG, and P53 was investigated using real-time PCR. The activity of antioxidant and malondialdehyde enzymes was measured by calorimetric methods.

Results

Analysis of gene expression showed that hydroxytyrosol significantly increased the expression of CASP3 and the BAX:BCL2 ratio in treatment groups compared to the control (P<0.05). Also, hydroxytyrosol significantly reduced the expression of the NFE2L2 gene (P<0.05). Calorimetric analysis showed that hydroxytyrosol increased activity of the antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase in treatment groups significantly more than the control group and reduced thiobarbituric acid–reactive substances on an oxidative stress index (P<0.05).

Conclusion

Hydroxytyrosol may induce apoptosis in colorectal cancer cells by increasing the expression of CASP3 gene and increasing the BAX:BCL2 ratio. Also, hydroxytyrosol may increase the activity of antioxidant enzymes and reduce the proliferation of LS180 cells by changing the antioxidant-defense system in cancer cells.

Antioxidant and Antibacterial Properties of Carbosilane Dendrimers Functionalized with Polyphenolic Moieties

A new family of polyphenolic carbosilane dendrimers functionalized with ferulic, caffeic, and gallic acids has been obtained through a straightforward amidation reaction. Their antioxidant activity has been studied by different techniques such as DPPH (2,2′-diphenyl-1-picrylhydrazyl) radical scavenging assay, FRAP assay (ferric reducing antioxidant power), and cyclic voltammetry. The antioxidant analysis showed that polyphenolic dendrimers exhibited higher activities than free polyphenols in all cases. The first-generation dendrimer decorated with gallic acid stood out as the best antioxidant compound, displaying a correlation between the number of hydroxyl groups in the polyphenol structure and the antioxidant activity of the compounds. Moreover, the antibacterial capacity of these new systems has been screened against Gram-positive (+) and Gram-negative (−) bacteria, and we observed that polyphenolic dendrimers functionalized with caffeic and gallic acids were capable of decreasing bacterial growth. In contrast, ferulic carbosilane dendrimers and free polyphenols showed no effect, establishing a correlation between antioxidant activity and antibacterial capacity. Finally, a viability assay in human skin fibroblasts cells (HFF-1) allowed for corroborating the nontoxicity of the polyphenolic dendrimers at their active antibacterial concentration.

Dietary Antioxidants and Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative disorder caused by the depletion of dopaminergic neurons in the basal ganglia, the movement center of the brain. Approximately 60,000 people are diagnosed with PD in the United States each year. Although the direct cause of PD can vary, accumulation of oxidative stress-induced neuronal damage due to increased production of reactive oxygen species (ROS) or impaired intracellular antioxidant defenses invariably occurs at the cellular levels. Pharmaceuticals such as dopaminergic prodrugs and agonists can alleviate some of the symptoms of PD. Currently, however, there is no treatment to halt the progression of PD pathology. Due to the nature of PD, a long and progressive neurodegenerative process, strategies to prevent or delay PD pathology may be well suited to lifestyle changes like dietary modification with antioxidant-rich foods to improve intracellular redox homeostasis. In this review, we discuss cellular and genetic factors that increase oxidative stress in PD. We also discuss neuroprotective roles of dietary antioxidants including vitamin C, vitamin E, carotenoids, selenium, and polyphenols along with their potential mechanisms to alleviate PD pathology.