Comparison survey of EVOO polyphenols and exploration of healthy aging-promoting properties of oleocanthal and oleacein

Oleacein: A comprehensive review of its extraction, purification, absorption, metabolism, and health effects

Extra virgin olive oil (EVOO) consumption reduces the risk of cardiovascular disease in high-risk groups and the polyphenols in EVOO play an important health effect on it. As one of the most abundant polyphenols in EVOO, oleacein (OLEA) has many health benefits. However, there is no review article that focus comprehensively on OLEA, and most articles have limited data and information on OLEA. The purpose of this review is to summarize the results of all available studies, to present and compare the main traditional and novel techniques for the extraction and isolation and purification of OLEA, to elucidate the absorption and metabolic pathways of OLEA, and finally, to illustrate the health-promoting properties. Hopefully, this review can promote the use of OLEA in functional foods and therapeutic fields.

The role of Caenorhabditis elegans in the discovery of natural products for healthy aging

Covering: 2012 to 2023The human population is aging. Thus, the greatest risk factor for numerous diseases, such as diabetes, cancer and neurodegenerative disorders, is increasing worldwide. Age-related diseases do not typically occur in isolation, but as a result of multi-factorial causes, which in turn require holistic approaches to identify and decipher the mode of action of potential remedies. With the advent of C. elegans as the primary model organism for aging, researchers now have a powerful in vivo tool for identifying and studying agents that effect lifespan and health span. Natural products have been focal research subjects in this respect. This review article covers key developments of the last decade (2012-2023) that have led to the discovery of natural products with healthy aging properties in C. elegans. We (i) discuss the state of knowledge on the effects of natural products on worm aging including methods, assays and involved pathways; (ii) analyze the literature on natural compounds in terms of their molecular properties and the translatability of effects on mammals; (iii) examine the literature on multi-component mixtures with special attention to the studied organisms, extraction methods and efforts regarding the characterization of their chemical composition and their bioactive components. (iv) We further propose to combine small in vivo model organisms such as C. elegans and sophisticated analytical approaches ("wormomics") to guide the way to dissect complex natural products with anti-aging properties.

Bioactive compounds in Spanish extra virgin olive oils: Migration and stability according to the culinary technique used

Extra virgin olive oil (EVOO) is a basic food of the Mediterranean diet and an important source of bioactive compounds, especially phenolic substances. The culinary techniques to which the oil is subjected before consumption cause the migration of these compounds, hence the importance of studying their stability before and after culinary treatment. We determined the behaviour of the phenols present in EVOO and its total antioxidant capacity before and after the use of various culinary techniques such as deep frying, boiling (in a water/oil mixture (W/O) and sauteing, observing that the study parameters varied according to the variety of oil and the culinary technique used. Significant statistical differences were observed between the different varieties of EVOO according to the culinary technique used. But this was not the case with respect to polyphenol content, for which no statistically significant differences were observed among the different varieties of EVOO according to the culinary techniques employed (p > 0.05), except with the Arbequina variety (p < 0.05). With respect to the individual polyphenols - tyrosol, p-vainillin, vanillic acid, gallic acid, trans-caffeic acid, ferulic acid and luteolin - our analysis shows that although there were differences in content between raw EVOO and EVOO treated with each of the culinary techniques, these differences were not statistically significant (p > 0.05). There were significant losses of oleocanthal with the W/O boiling technique, but content increases were observed following sauteing and deep frying with respect to raw EVOO. Total antioxidant capacity presented a similar pattern in all samples, with increases after sauteing and decreases after W/O boiling and deep frying. ABTS was the most suitable technique for determining antioxidant capacity in EVOO. In short, the behaviour of the bioactive compounds in EVOO depends on the temperature and the cooking medium used.

Insights into the Antioxidant/Antiradical Effects and In Vitro Intestinal Permeation of Oleocanthal and Its Metabolites Tyrosol and Oleocanthalic Acid

(1) Background: In recent years, numerous studies have highlighted the beneficial effects of extra virgin olive oil (EVOO) as an active ingredient against chronic diseases. The properties of EVOO are due to its peculiar composition, mainly to its rich content of polyphenols. In fact, polyphenols may contribute to counteract oxidative stress, which often accompanies chronic diseases. In this work, the antioxidant effects of high-value polyphenol oleocanthal (OC) and its main metabolites, tyrosol (Tyr) and oleocanthalic acid (OA), respectively, have been investigated along with their impact on cell viability. (2) Methods: OC, Tyr, and OA have been evaluated regarding antiradical properties in term of scavenging capacity towards biologically relevant reactive species, including O2●-, HOCl, and ROO●, as well as their antioxidant/antiradical capacity (FRAP, DPPH●, ABTS●+). Moreover, the ability to permeate the intestinal membrane was assessed by an intestinal co-culture model composed by Caco-2 and HT29-MTX cell lines. (3) Results: The capacity of OC and Tyr as radical oxygen species (ROS) scavengers, particularly regarding HOCl and O2●-, was clearly demonstrated. Furthermore, the ability to permeate the intestinal co-culture model was plainly proved by the good permeations (>50%) achieved by all compounds. (4) Conclusions: OC, OA, and Tyr revealed promising properties against oxidative diseases.

Oleocanthal - Characterization, production, safety, functionality and in vivo evidences

Oleocanthal, OC, 2-(4-Hydroxyphenyl)ethyl(3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate, is a natural organic compound exclusively found in Olea europaea L. (Oleoaceae), such as extra virgin olive oil (EVOO). Chemically, it is considered a monophenolic secoiridoid, taking part of the validated antioxidants naturally occurring in some plant-based foods. In this review, the aim is to summarize the identity and characteristics of this molecule, where it can be obtained (isolation from the natural source or chemical synthesis), as well as the use as food component. Then, the bioavailability, safety and studies aiming to demonstrate the potential health benefits, including in vitro and in vivo animal and human studies were also discussed.

Co-Extraction Technique Improves Functional Capacity and Health-Related Benefits of Olive Oils: A Mini Review

Olive oil, a fundamental component of the Mediterranean diet, is recognized as a functional food due to its health-promoting composition. The concentration of phenolic compounds in olive oil is influenced by various factors such as genetics, agro-climatic conditions, and technological processes. Therefore, to ensure an ideal intake of phenolics through the diet, it is recommended to produce functional enriched olive oil that contains a high concentration of bioactive compounds. The co-extraction technique is used to create innovative and differentiated products that promote the sensory and health-related composition of oils. To enrich olive oil, various natural sources of bioactive compounds can be used, including raw materials derived from the same olive tree such as olive leaves, as well as other compounds from plants and vegetables, such as herbs and spices (garlic, lemon, hot pepper, rosemary, thyme, and oregano). The development of functional enriched olive oils can contribute to the prevention of chronic diseases and improve consumers' quality of life. This mini-review compiles and discusses relevant scientific information related to the development of enriched olive oil using the co-extraction technique and its positive effects on the health-related composition of oils.

Synthesis, DFT study, theoretical and experimental spectroscopy of fatty amides based on extra-virgin olive oil and their antibacterial activity

Medication products from natural materials are preferred due to their minimal side effects. Extra-virgin olive oil (EVOO) is a highly acclaimed Mediterranean diet and a common source of lipids that lowers morbidity and disease severity. This study synthesised two fatty amides from EVOO: hydroxamic fatty acids (FHA) and fatty hydrazide hydrate (FHH). The Density Functional Theory (DFT) was applied to quantum mechanics computation. Nuclear magnetic resonance (NMR), Fourier transforms infrared (FTIR), and element analysis were used to characterise fatty amides. Likewise, the minimum inhibitory concentration (MIC) and timing kill assay were determined. The results revealed that 82 % for FHA and 80 % for FHH conversion were achieved. The amidation reagent/EVOO ratio (mmol: mmol) was 7:1, using the reaction time of 12 h and hexane as an organic solvent. The results further revealed that fatty amides have high antibacterial activity with low concentration at 0.04 μg/mL during eight h of FHA and 0.3 μg/mL during ten h of FHH. This research inferred that FHA and FHH could provide an alternative and effective therapeutic strategy for bacterial diseases. Current findings could provide the basis for the modernisation/introduction of novel and more effective antibacterial drugs derived from natural products.

NMR-Based Metabolite Profiling and the Application of STOCSY toward the Quality and Authentication Assessment of European EVOOs

Extra virgin olive oil (EVOO) possesses a high-value rank in the food industry, thus making it a common target for adulteration. Hence, several methods have been essentially made available over the years. However, the issue of authentication remains unresolved with national and food safety organizations globally struggling to regulate and control its market. Over the course of this study, the aim was to determine the origin of EVOOs suggesting a high-throughput, state-of-the-art method that could be easily adopted. A rapid, NMR-based untargeted metabolite profiling method was applied and complemented by multivariate analysis (MVA) and statistical total correlation spectroscopy (STOCSY). STOCSY is a valuable statistical tool contributing to the biomarker identification process and was employed for the first time in EVOO analysis. Market samples from three Mediterranean countries of Spain, Italy, and Greece, blended samples from these countries, as well as monocultivar samples from Greece were analyzed. The NMR spectra were collected, with the help of chemometrics acting as "fingerprints" leading to the discovery of certain chemical classes and single biomarkers that were related to the classification of the samples into groups based on their origin.

Direct In Vitro Comparison of the Anti-Leishmanial Activity of Different Olive Oil Total Polyphenolic Fractions and Assessment of Their Combined Effects with Miltefosine

The bioactive compounds present in the edible products of the olive tree have been extensively studied and their favorable effects on various disease risk factors have been demonstrated. The aim of this study was to perform a comparative analysis of the anti-leishmanial effects of total phenolic fractions (TPFs) derived from extra virgin olive oil with different phenolic contents and diverse quantitative patterns. Moreover, the present study investigated their association with miltefosine, a standard anti-leishmanial drug, against both extracellular promastigotes and intracellular amastigotes of a viscerotropic and a dermotropic Leishmania strain. The chemical compositions of TPFs were determined by high performance liquid chromatography with diode array detection (HPLC-DAD). Analysis of parasite growth kinetics, reactive oxygen species production and apoptotic events were determined by microscopy and flow cytometry. Our results revealed that the presence of oleacein (OLEA) and oleocanthal (OLEO) secoiridoids enhances the anti-leishmanial effect of TPF. The association between TPFs and miltefosine was suggested as being additive in Leishmania infantum and Leishmania major promastigotes, and as antagonistic in intracellular amastigotes, as was evaluated with the modified isobologram method. The obtained data verified that TPFs are bioactive dietary extracts with a strong anti-leishmanial activity and highlighted that fractions that are richer in OLEA and OLEO phenolic compounds possess stronger inhibitory effects against parasites. This study may contribute to improving the therapeutic approaches against leishmaniasis.

Oxidized Forms of Olive Oil Secoiridoids: Semisynthesis, Identification and Correlation with Quality Parameters

Secoiridoids is the prominent chemical class of olive oil polar constituents and are characterized by significant biological properties. They are abundant in different chemical forms and relatively high concentrations compared to other components, while prone to oxidation due to their chemical motif. In recent years, oxidized derivatives of secoiridoids have been reported, either as natural constituents of olive oil or as components which are gradually formed in all stages of its production and storage. The mono-oxidized forms of oleocanthal and oleacein named as the respective acids have been recently isolated from olive oil and unambiguously structurally characterized. Other oxidized forms of elenolic acid or more complex secoiridoids, such as those of oleuropein and ligstroside aglycones are also sporadically mentioned in the literature. No further information is provided since they have not been isolated in pure form in order to be accurately identified. Most of the time, they are generally referred as oxidized forms of the parent compounds and commonly identified based on mass spectrometric data. In the current study, the semi-synthesis of the main oxidized olive oil secoiridoids, i.e., oleocanthalic acid, oleaceinic acid, EDA acid, carboxylic form of elenolic acid, carboxylic form of ligstroside aglycon, and carboxylic form of oleuropein aglycon is described starting from the corresponding aldehydic derivatives, using SeO₂/H₂O₂ as oxidative agents. Furthermore, their presence in a number of Greek olive oils was investigated as well, as possible correlation thereof with quality parameters.

miR-129 Promotes the Proliferation of Alzheimer’s Neuronal Cells by Binding the 3′ Untranslated Regions (3′ UTR) of Amyloid Precursor Protein (APP)

Alzheimer’s disease (AD) is a neurodegenerative disease with memory loss and cognitive impairment. Short non-coding RNAs (miRNAs) are potential biomarkers and therapeutic targets for AD. This study aims to investigate miR-129’s role in AD. miR-129 and amyloid precursor protein (APP) expression was measured by Q-PCR, and LC3, p62, ATG5, Bcl-2, p-Tau and Caspase3 protein was detected by Western blot. Hydrogenase kits and DCFH-DA detected cell apoptosis, cytotoxicity and ROS generation. The interaction between APP and miR-129 was assessed by luciferase report experiment. HE staining and TUNEL assay evaluated hippocampal neuron damage. In AD patient serum, AD transgenic (TG) mouse brain tissue, and AB1-42-treated SH-SY5Y cells, miR-129 was downregulated but autophagy was increased. Overexpression of miR-129 reduced cell damage induced by AB1-42, and miR-129 can directly regulate APP expression by binding APP 3′-UTR. miR-129 inhibitors reversed the protective effect of shAPP on AB1-42-induced cell damage. In addition, miR-129 overexpression reduced neuronal damage through inhibiting autophagy in vivo. APP expression in AD patient and AD cell model was significantly increased compared to controls. Aβ-42 treatment caused up-regulation of APP expression, while APP knockdown inhibited neurons through autophagy. In conclusion, miR-129 overexpression can regulate autophagy by targeting APP5, thereby reducing neuronal damage in AD. These findings provide a new perspective for treating AD.

From Low-Quality Olive Oils to Valuable Bioactive Compounds: Obtaining Oleacein and Oleocanthal from Olive Oils Intended for Refining

The aim of this work was to recover phenolic compounds such as oleacein and oleocanthal from low commercial value olive oils destined for refining [lampante olive oil (LOO)]. For this, the ability of three extraction systems of phenols from oils was evaluated. A new quick and simple extraction method (NM) for obtaining phenols was developed, consisting of the acidified mixture MeOH/H₂O (50:50) (v/v) 0.1% formic acid, and it was compared to a conventional method (CM) widely used for the analytical determination of phenolic compounds in olive oil using MeOH: H₂O (80:20) (v/v). NM showed a higher yield for the extraction of oleacein with an increase of 14% compared to CM; no significant differences were observed in the extraction of oleocanthal between the two methods. The third method, using two formulations of deep eutectic solvents (DESs) based on ChCl, showed higher extractive efficiency for the two secoiridoids than CM and NM when DES consisted of ChCl and xylitol. On the other hand, the concentrations of oleacein and oleocanthal were determined in 14 samples of blended oils that were previously classified as extra virgin olive oil and LOO according to EU regulation. LOO contained amounts up to 109.89 and 140.16 mg/kg of oleacein and oleocanthal, respectively. Oleacein (>98%) and oleocanthal (>95%) were successfully recovered from phenolic extracts obtained from LOO oils through chromatographic separation and purification by semipreparative high-performance liquid chromatography. Therefore, these low-quality oils are an inexpensive source of bioactive substances.

Extra virgin olive oil-based phospholipid complex/self-microemulsion enhances oral absorption of salvianolic acid B through inhibition of catechol-O-methyltransferase-mediated metabolism

The oral bioavailability of many phenolic acid drugs is severely limited due to the high hydrophilicity and extensive first-pass effect induced by catechol-O-methyltransferase (COMT) metabolism. The present study investigated the inhibitory activity of the pharmaceutical excipients of extra virgin olive oil (EVOO) against COMT and evaluated the potential of a self-microemulsion loaded with a phospholipid complex containing EVOO for oral absorption enhancement of salvianolic acid B (SAB), a model phenolic acid. In vitro COMT assay showed that EVOO could effectively inhibit enzyme activity in the rat liver cytosol. Next, the SAB phospholipid complex/self-microemulsion containing EVOO (named SP-SME1) was prepared and characterized (particle size, 243.60 ± 6.96 nm and zeta potential, -23.67 ± -1.36 mV). The phospholipid complex/self-microemulsion containing ethyl oleate (EO) (named SP-SME2) was taken as the control group. Compared with free SAB, the apparent permeability coefficient (P_app value) of the two SP-SMEs significantly increased (12.0-fold and 10.90-fold). Pharmacokinetic study demonstrated that the AUC_0-∞ value of SAB for the SP-SME1 group significantly increased by 4.72 and 2.82 times compared to those for free SAB (p < 0.001) and SP-SME2 (p < 0.01), respectively. Moreover, the AUC_0-∞ value of monomethyl-SAB (metabolite of SAB, MMS) for the SP-SME1 group decreased by 0.83 times compared to that for SP-SME2. In conclusion, the EVOO-based phospholipid complex/self-microemulsion greatly enhanced the oral absorption of SAB, which was mainly attributed to the inhibition of COMT activity induced by EVOO.

Isolation of an Extract from the Soft Coral Symbiotic Microorganism Salinispora arenicola Exerting Cytoprotective and Anti-Aging Effects

Cells have developed a highly integrated system responsible for proteome stability, namely the proteostasis network (PN). As loss of proteostasis is a hallmark of aging and age-related diseases, the activation of PN modules can likely extend healthspan. Here, we present data on the bioactivity of an extract (SA223-S2BM) purified from the strain Salinispora arenicola TM223-S2 that was isolated from the soft coral Scleronephthya lewinsohni; this coral was collected at a depth of 65 m from the mesophotic Red Sea ecosystem EAPC (south Eilat, Israel). Treatment of human cells with SA223-S2BM activated proteostatic modules, decreased oxidative load, and conferred protection against oxidative and genotoxic stress. Furthermore, SA223-S2BM enhanced proteasome and lysosomal-cathepsins activities in Drosophila flies and exhibited skin protective effects as evidenced by effective inhibition of the skin aging-related enzymes, elastase and tyrosinase. We suggest that the SA223-S2BM extract constitutes a likely promising source for prioritizing molecules with anti-aging properties.

A Study on the Clustering of Extra Virgin Olive Oils Extracted from Cultivars Growing in Four Ionian Islands (Greece) by Multivariate Analysis of Their Phenolic Profile, Antioxidant Activity and Genetic Markers

Background: The phenolic fraction of extra virgin olive oil (EVOO) has disease preventive and health-promoting properties which are supported by numerous studies. As such, EVOO is defined as a functional food. The aim of the present study was to characterize the phenolic profile of olive oil from cultivars farmed in the Ionian Islands (Zakynthos, Kefalonia, Lefkada, and Kerkyra) and to investigate the association of phenols to antioxidant activity, which is central to its functionality. Furthermore, the study investigates whether multivariate analyses on the concentration of individual biophenolic compounds and genetic population diversity could classify the olive oil samples based on their geographic origin. Methods: Phenols were determined in 103 samples from different Ionian Island tree populations by ¹H nuclear magnetic resonance (NMR), and sample antioxidant activity was measured by their capacity to reduce the free radical 2,2-diphenyl-1-picrylhydrazyl) (DPPH). Genetic diversity was measured by estimating Nei’s population genetic distance using 15 reproducible bands from random amplified polymorphic DNA (RAPD) genotyping. Results: Principal component analysis (PCA) of the secoiridoid concentrations clustered samples according to cultivar. Clustering based on genetic distances is not concordant with phenolic clustering. A cultivar effect was also demonstrated in the association between the concentration of individual phenols with DPPH reducing activity. Conclusions: Taken together, the study shows that the olive oil phenolic content defines “cultivar-specific phenolic profiles” and that environmental factors other than agronomic conditions contribute more to phenotype variance than genetics.

Activation of specific bitter taste receptors by olive oil phenolics and secoiridoids

Extra-virgin olive oil (EVOO) is a critical component of the Mediterranean diet, which has been found beneficial to human health. Bitterness is often positively associated with the presence of phenolic compounds in EVOO. There are twenty-five bitter taste receptors (TAS2Rs) in humans, each of which responds to specific bitter tastants. The identity of phenolic compounds and the bitter taste receptors they stimulate remain unknown. In this study, we isolated 12 phenolic and secoiridoid compounds from the olive fruit and the oil extracted from it, and tested their ability to stimulate bitter taste receptor activity, using a calcium mobilization functional assay. Our results showed that seven out of twelve studied compounds activated TAS2R8, and five of them activated TAS2R1, TAS2R8, and TAS2R14. The phenolic compounds oleuropein aglycon and ligstroside aglycon were the most potent bitter tastants in olive oil. TAS2R1 and TAS2R8 were the major bitter taste receptors activated most potently by these phenolic compounds. The results obtained here could be utilized to predict and control the bitterness of olive oil based on the concentration of specific bitter phenolics produced during the milling process of olives.

LC-ESI-LTQ-Orbitrap-MS for Profiling the Distribution of Oleacein and Its Metabolites in Rat Tissues

The purpose of this work was to study the distribution of oleacein (OLEA) and its metabolites in rat plasma and different tissues, namely brain, heart, kidney, liver, lung, small intestine, spleen, stomach, skin, and thyroid, following the acute intake of a refined olive oil containing 0.3 mg/mL of OLEA. For this purpose, a distribution kinetics study was carried out. The plasma and tissues were collected at 1, 2, and 4.5 h after the intervention, and analyzed by LC-ESI-LTQ-Orbitrap-MS. Unmetabolized OLEA was detected in the stomach, small intestine, liver, plasma and, most notably, the heart. This finding may be useful for the development of new applications of OLEA for cardiovascular disease prevention. Noteworthy are also the high levels of hydroxytyrosol (OH-TY) and OLEA + CH₃ found in the small intestine, liver, and plasma, and the detection of nine OLEA metabolites, five of them arising from conjugation reactions. Liver, heart, spleen, and lungs were the target tissues where the metabolites were most distributed. However, it is important to note that OH-TY, in our experimental conditions, was not detected in any target tissue (heart, spleen, thyroids, lungs, brain, and skin). These results shed further light on the metabolism and tissue distribution of OLEA and contribute to understanding the mechanisms underlying its effect in human health.

Tissue Distribution of Oleocanthal and Its Metabolites after Oral Ingestion in Rats

Claims for the potential health benefits of oleocanthal (OLC), a dietary phenolic compound found in olive oil, are based mainly on in vitro studies. Little is known about the tissue availability of OLC, which is rapidly metabolized after ingestion. In this study, the distribution of OLC and its metabolites in rat plasma and tissues (stomach, intestine, liver, kidney, spleen, lungs, heart, brain, thyroid and skin) at 1, 2 and 4.5 h after the acute intake of a refined olive oil containing 0.3 mg/mL of OLC was examined by LC-ESI-LTQ-Orbitrap-MS. OLC was only detected in the stomach and intestine samples. Moreover, at 2 and 4.5 h, the concentration in the stomach decreased by 36% and 74%, respectively, and in the intestine by 16% and 33%, respectively. Ten OLC metabolites arising from phase I and phase II reactions were identified. The metabolites were widely distributed in rat tissues, and the most important metabolizing organs were the small intestine and liver. The two main circulating metabolites were the conjugates OLC + OH + CH₃ and OLC + H₂O + glucuronic acid, which may significantly contribute to the beneficial health effects associated with the regular consumption of extra virgin olive oil. However, more studies are necessary to determine the concentrations and molecular structures of OLC metabolites in human plasma and tissues when consumed with the presence of other phenolic compunds present in EVOO.

Antioxidant Properties and Fatty Acid Profile of Cretan Extra Virgin Bioolive Oils: A Pilot Study

Olive oil is considered a valuable ingredient of human diet. It is a good source of mono- and polyunsaturated fatty acids, as well as other bioactive compounds, especially polyphenols. The composition of olive oil depends mainly on the variety of plant, cultivation practices, and manufacturing conditions. Traditional processing methods may ensure better quality and health benefits. Therefore, the aim of the study was the evaluation of antioxidant properties and fatty acid profile of Cretan extra virgin bioolive oils. These ones were compared with commercial Spanish, Italian, and Greek extra virgin olive oils. Obtained results showed that sample Cretan 1 had about 15% higher antioxidant capacity and about 60% higher total polyphenol content than commercial counterparts. This one had also a favorable profile of fatty acids, especially 20% more linoleic acid. We concluded that traditional production methods, using millstones, cold pressing, and without centrifugation and filtration ensure better olive oil quality and related health benefits.

The Impact of Formulation on the Content of Phenolic Compounds in Snacks Enriched with Dracocephalum moldavica L. Seeds: Introduction to Receiving a New Functional Food Product

A new type of multigrain snack has been designed containing varied additions of Moldavian dragonhead (Dracocephalum moldavica L.) seeds. The antioxidant properties and the general health benefits of this plant material have already been widely acknowledged. The research discussed herein aimed to investigate the influence of the formulation and expansion method (frying) on the content of polyphenolic compounds, individual phenolic acids, and antiradical properties of innovative snacks enriched with dragonhead seeds. The highest content of polyphenols (0.685 mg GAE/mL), free phenolic acids (47.052 µg/g of dry matter), and highest radical scavenging activity (96.23% towards DPPH) were found in the fried snacks enriched with 22% of seeds. In these samples, 11 phenolic acids were detected. Strong positive correlations were seen between the addition of dragonhead and the polyphenol content (r = 0.989) and between the quantity of the enriching additive and the content of free phenolic acids (r = 0.953). The research has shown that such innovative snacks have the potential to supply health-benefiting free phenolic acids, e.g., salicylic, isoferulic, ferulic, p-coumaric, vanillic. Our studies provide an introduction to the development of a new range of functional foods.

A New Definition of the Term "High-Phenolic Olive Oil" Based on Large Scale Statistical Data of Greek Olive Oils Analyzed by qNMR

In the last few years, a new term, “High-phenolic olive oil”, has appeared in scientific literature and in the market. However, there is no available definition of that term regarding the concentration limits of the phenolic ingredients of olive oil. For this purpose, we performed a large-scale screening and statistical evaluation of 5764 olive oil samples from Greece coming from >30 varieties for an eleven-year period with precisely measured phenolic content by qNMR. Although there is a large variation among the different cultivars, the mean concentration of total phenolic content was 483 mg/kg. The maximum concentration recorded in Greece reached 4003 mg/kg. We also observed a statistically significant correlation of the phenolic content with the harvest period and we also identified varieties affording olive oils with higher phenolic content. In addition, we performed a study of phenolic content loss during usual storage and we found an average loss of 46% in 12 months. We propose that the term high-phenolic should be used for olive oils with phenolic content > 500 mg/kg that will be able to retain the health claim limit (250 mg/kg) for at least 12 months after bottling. The term exceptionally high phenolic olive oil should be used for olive oil with phenolic content > 1200 mg/kg (top 5%).

Bioactive Secoiridoids in Italian Extra-Virgin Olive Oils: Impact of Olive Plant Cultivars, Cultivation Regions and Processing

In the last two decades, phenolic compounds occurring in olive oils known as secoiridoids have attracted a great interest for their bioactivity. Four major olive oil secoiridoids, i.e., oleuropein and ligstroside aglycones, oleacin and oleocanthal, were previously characterized in our laboratory using reversed-phase liquid chromatography with electrospray ionization-Fourier transform-mass spectrometry (RPLC-ESI-FTMS). The same analytical approach, followed by multivariate statistical analysis (i.e., Principal Component Analysis), was applied here to a set of 60 Italian extra-virgin olive oils (EVOO). The aim was to assess the secoiridoid contents as a function of olive cultivars, place of cultivation (i.e., different Italian regions) and olive oil processing, in particular two- vs. three-phase horizontal centrifugation. As expected, higher secoiridoid contents were generally found in olive oils produced by two-phase horizontal centrifugation. Moreover, some region/cultivar-related trends were evidenced, as oleuropein and ligstroside aglycones prevailed in olive oils produced in Apulia (Southern Italy), whereas the contents of oleacin and oleocanthal were relatively higher in EVOO produced in Central Italy (Tuscany, Lazio and Umbria). A lower content of all the four secoiridoids was generally found in EVOO produced in Sicily (Southern Italy) due to the intrinsic low abundance of these bioactive compounds in cultivars typical of that region.

Olive Oil Quality and Authenticity Assessment Aspects Employing FIA-MRMS and LC-Orbitrap MS Metabolomic Approaches

Edible vegetable oils comprise integral components of humans' daily diet during the lifetime. Therefore, they constitute a central part of dietary-exposome, which among other factors regulates human health. In particular, the regular consumption of olive oil (OO) has been largely accepted as a healthy dietary pattern. Responsible for its recognition as a superior edible oil is its exceptional aroma and flavor. Its unique composition is characterized by high levels of monounsaturated fatty acids and the presence of minor constituents with important biological properties, such as the so-called OO polyphenols. Being a high added value product, OO suffers from extensive fraud and adulteration phenomena. However, its great chemical complexity, variability, and the plethora of parameters affecting OO composition hamper significantly the selection of the absolute criteria defining quality and authenticity, and a reliable and robust methodology is still unavailable. In the current study, Flow Injection Analysis-Magnetic Resonance Mass Spectrometry (FIA-MRMS) was investigated under a metabolic profiling concept for the analysis of Greek Extra Virgin Olive Oils (EVOO). More than 200 monovarietal (Koroneiki) EVOO samples were collected from the main Greek OO producing regions and investigated. Both intact oil and the corresponding polyphenols were analyzed in fast analysis time of 2 and 8 min, respectively. In parallel, an LC-Orbitrap MS platform was used to verify the efficiency of the method as well as a tool to increase the identification confidence of the proposed markers. Based on the results, with FIA-MRMS, comparable and improved projection and prediction models were generated in comparison to those of the more established LC-MS methodology. With FIA-MRMS more statistically significant compounds and chemical classes were identified as quality and authenticity markers, associated with specific parameters, i.e. geographical region, cultivation practice, and production procedure. Furthermore, it was possible to monitor both lipophilic and hydrophilic compounds with a single analysis. To our knowledge, this approach is among the few studies in which two FT-MS platforms combining LC and FIA methods were integrated to provide solutions to quality control aspects of OO. Moreover, both lipophilic and hydrophilic components are analyzed together, providing a holistic quality control workflow for OO.

Structure-Biological Activity Relationships of Extra-Virgin Olive Oil Phenolic Compounds: Health Properties and Bioavailability

Extra-virgin olive oil is regarded as functional food since epidemiological studies and multidisciplinary research have reported convincing evidence that its intake affects beneficially one or more target functions in the body, improves health, and reduces the risk of disease. Its health properties have been related to the major and minor fractions of extra-virgin olive oil. Among olive oil chemical composition, the phenolic fraction has received considerable attention due to its bioactivity in different chronic diseases. The bioactivity of the phenolic compounds could be related to different properties such as antioxidant and anti-inflammatory, although the molecular mechanism of these compounds in relation to many diseases could have different cellular targets. The aim of this review is focused on the extra-virgin olive oil phenolic fraction with particular emphasis on (a) biosynthesis, chemical structure, and influence factors on the final extra-virgin olive oil phenolic composition; (b) structure–antioxidant activity relationships and other molecular mechanisms in relation to many diseases; (c) bioavailability and controlled delivery strategies; (d) alternative sources of olive biophenols. To achieve this goal, a comprehensive review was developed, with particular emphasis on in vitro and in vivo assays as well as clinical trials. This report provides an overview of extra-virgin olive oil phenolic compounds as a tool for functional food, nutraceutical, and pharmaceutical applications.

Bioactive Compounds and Quality of Extra Virgin Olive Oil

(1) Background: Extra virgin olive oil (EVOO) is responsible for a large part of many health benefits associated to Mediterranean diet as it is a fundamental ingredient of this diet. The peculiarities of this golden, highly valued product are in part due to the requirements that must be met to achieve this title, namely, it has to be obtained using exclusively mechanical procedures, its free acidity cannot be greater than 0.8%, it must not show sensory defects, and it has to possess a fruity taste. (2) Methods: All these characteristics are key factors to EVOO quality, thus the chemical composition of these many health-promoting compounds, such as unsaturated fatty acids (which are also the major compounds, especially oleic acid), as well as minor components such as tocopherols or phenolic compounds (which behave as natural antioxidants) must be preserved. (3) Results: Due to the presence of all these compounds, the daily consumption of EVOO entails health benefits such as cardioprotective, antioxidant, anti-inflammatory, anti-tumor properties or acting as regulator of the intestinal microbiota, among others. (4) Conclusions: Taking all together, conserving EVOO chemical composition is essential to preserve its properties, so it is worth to control certain factors during storage like exposure to light, temperature, oxygen presence or the chosen packaging material, to maintain its quality and extend its shelf-life until its consumption.

Influence of Horizontal Centrifugation Processes on the Content of Phenolic Secoiridoids and Their Oxidized Derivatives in Commercial Olive Oils: An Insight by Liquid Chromatography-High-Resolution Mass Spectrometry and Chemometrics

Reversed-phase liquid chromatography with electrospray ionization-high-resolution/accuracy Fourier transform mass spectrometry (RPC-ESI-FTMS) and chemometrics were exploited to evaluate the influence of horizontal centrifugation by two- or three-phase decanters on the content of major phenolic secoiridoids in extravirgin olive oils (EVOOs). Despite the occurrence of other potential sources of variability typical of commercial olive oils, horizontal centrifugation was found to play a primary role, with a general increase of secoiridoid content occurring when two-phase decanters were used. As emphasized by principal component analysis (PCA), the increase involved preferentially oleacin and oleocanthal, when oxidative deterioration was purposely minimized during and/or after production, and oleuropein and ligstroside aglycones, when no vertical centrifugation was performed at the end of the productive cycle. The influence of the type of horizontal centrifugation was also emphasized by the elaboration of RPC-ESI-FTMS data based on hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA).

Potential Protective Role Exerted by Secoiridoids from Olea europaea L. in Cancer, Cardiovascular, Neurodegenerative, Aging-Related, and Immunoinflammatory Diseases

Iridoids, which have beneficial health properties, include a wide group of cyclopentane [c] pyran monoterpenoids present in plants and insects. The cleavage of the cyclopentane ring leads to secoiridoids. Mainly, secoiridoids have shown a variety of pharmacological effects including anti-diabetic, antioxidant, anti-inflammatory, immunosuppressive, neuroprotective, anti-cancer, and anti-obesity, which increase the interest of studying these types of bioactive compounds in depth. Secoiridoids are thoroughly distributed in several families of plants such as Oleaceae, Valerianaceae, Gentianaceae and Pedialaceae, among others. Specifically, Olea europaea L. (Oleaceae) is rich in oleuropein (OL), dimethyl-OL, and ligstroside secoiridoids, and their hydrolysis derivatives are mostly OL-aglycone, oleocanthal (OLE), oleacein (OLA), elenolate, oleoside-11-methyl ester, elenoic acid, hydroxytyrosol (HTy), and tyrosol (Ty). These compounds have proved their efficacy in the management of diabetes, cardiovascular and neurodegenerative disorders, cancer, and viral and microbial infections. Particularly, the antioxidant, anti-inflammatory, and immunomodulatory properties of secoiridoids from the olive tree (Olea europaea L. (Oleaceae)) have been suggested as a potential application in a large number of inflammatory and reactive oxygen species (ROS)-mediated diseases. Thus, the purpose of this review is to summarize recent advances in the protective role of secoiridoids derived from the olive tree (preclinical studies and clinical trials) in diseases with an important pathogenic contribution of oxidative and peroxidative stress and damage, focusing on their plausible mechanisms of the action involved.

Changes in the Antioxidant Properties of Extra Virgin Olive Oil after Cooking Typical Mediterranean Vegetables

Extra virgin olive oil (EVOO), water, and a water/oil mixture (W/O) were used for frying, boiling and sautéeing Mediterranean vegetables (potato, pumpkin, tomato and eggplant). Differences in antioxidant capacity (AC) (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric iron (FRAP), 2,2-azinobis-(3-ethylbensothiazoline)-6-sulphonic acid (ABTS)), total phenolic content (TPC) and individual phenols (high-performance liquid chromatography (HPLC)) in unused and used EVOO and water were determined. The water used to boil tomatoes showed the highest TPC value, whilst the lowest was found in the EVOO from the W/O used for boiling potatoes. After processing, the concentrations of phenols exclusive to EVOO diminished to different extents. There was a greater transfer of phenols from the vegetable to the oil when eggplant, tomato and pumpkin were cooked. W/O boiling enriched the water for most of the phenols analysed, such as chlorogenic acid and phenols exclusive to EVOO. The values of AC decreased or were maintained when fresh oil was used to cook the vegetables (raw > frying > sautéing > boiling). The water fraction was enriched in 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid (Trolox) equivalents following boiling, though to a greater extent when EVOO was added. Phenolic content and AC of EVOO decreased after cooking Mediterranean diet vegetables. Further, water was enriched after the boiling processes, particularly when oil was included.

Nutrigenomics as a tool to study the impact of diet on aging and age-related diseases: the Drosophila approach

Aging is a complex phenomenon caused by the time-dependent loss of cellular homeodynamics and consequently of physiological organismal functions. This process is affected by both genetic and environmental (e.g., diet) factors, as well as by their constant interaction. Consistently, deregulation of nutrient sensing and signaling pathways is considered a hallmark of aging. Nutrigenomics is an emerging scientific discipline that studies changes induced by diet on the genome and thus it considers the intersection of three topics, namely health, diet, and genomics. Model organisms, such as the fruit fly Drosophila melanogaster, have been successfully used for in vivo modeling of higher metazoans aging and for nutrigenomic studies. Drosophila is a well-studied organism with sophisticated genetics and a fully annotated sequenced genome, in which ~ 75% of human disease-related genes have functional orthologs. Also, flies have organs/tissues that perform the equivalent functions of most mammalian organs, while discrete clusters of cells maintain insect carbohydrate homeostasis in a way similar to pancreatic cells. Herein, we discuss the mechanistic connections between nutrition and aging in Drosophila, and how this model organism can be used to study the effect of different diets (including natural products and/or their derivatives) on higher metazoans longevity.

The extra virgin olive oil phenolic oleacein is a dual substrate-inhibitor of catechol-O-methyltransferase

Catechol-containing polyphenols present in coffee and tea, while serving as excellent substrates for catechol-O-methyltransferase (COMT)-catalyzed O-methylation, can also operate as COMT inhibitors. However, little is known about the relationship between COMT and the characteristic phenolics present in extra virgin olive oil (EVOO). We here selected the EVOO dihydroxy-phenol oleacein for a computational study of COMT-driven methylation using classic molecular docking/molecular dynamics simulations and hybrid quantum mechanical/molecular mechanics, which were supported by in vitro activity studies using human COMT. Oleacein could be superimposed onto the catechol-binding site of COMT, maintaining the interactions with the atomic positions involved in methyl transfer from the S-adenosyl-L-methionine cofactor. The transition state structure for the meta-methylation in the O5 position of the oleacein benzenediol moiety was predicted to occur preferentially. Enzyme analysis of the conversion ratio of catechol to O-alkylated guaiacol confirmed the inhibitory effect of oleacein on human COMT, which remained unaltered when tested against the protein version encoded by the functional Val¹⁵⁸Met polymorphism of the COMT gene. Our study provides a theoretical determination of how EVOO dihydroxy-phenols can be metabolized via COMT. The ability of oleacein to inhibit COMT adds a new dimension to the physiological and therapeutic utility of EVOO secoiridoids.