Pinoresinol and 1-acetoxypinoresinol, two new phenolic compounds identified in olive oil

Characterization of Olive Oil Phenolic Extracts and Their Effects on the Aggregation of the Alzheimer's Amyloid-β Peptide and Tau

The dietary consumption of extra virgin olive oil (EVOO) is believed to slow the progression of Alzheimer's disease (AD) symptoms. Its protective mechanisms are unclear, but specific EVOO phenolic compounds can individually impede the aggregation of amyloid-β (Aβ) peptides and the microtubule-associated protein tau, two important pathological manifestations of AD. It is unknown, however, whether the numerous and variable phenolic compounds that are consumed in dietary EVOO can collectively alter tau and Aβ aggregation as effectively as the individual compounds. The activity of these complex mixtures against Aβ and tau may be moderated by competition between active and nonactive phenolic components and by extensive derivatizations and isomerization. Here, phenolic mixtures extracted from two different EVOO sources are characterized and tested for how they modulate the aggregation of Aβ40 peptide and tau peptides in vitro. The chromatographic and NMR analysis of Greek and Saudi Arabian EVOO phenolic extracts reveals that they have different concentration profiles, and over 30 compounds are identified. Thioflavin T fluorescence and circular dichroism measurements show that relatively low concentrations (<20 μg/mL) of the Greek and Saudi extracts reduce the rate of Aβ40 aggregation and fibril mass, despite the extracts having different phenolic profiles. By contrast, the Greek extract reduces the rate of tau aggregation only at very high phenolic concentrations (>100 μg/mL). Most compounds in the extracts bind to preformed Aβ40 fibrils and release soluble Aβ oligomers that are mildly toxic to SH-SY5Y cells. Much higher (500 μg/mL) extract concentrations are required to remodel tau filaments into oligomers, and a minimal binding of phenolic compounds to the preformed filaments is observed. It is concluded that EVOO extracts having different phenol profiles are similarly capable of modulating Aβ40 aggregation and fibril morphology in vitro at relatively low concentrations but are less efficient at modulating tau aggregation. Over 2 M tonnes of EVOO are consumed globally each year as part of the Mediterranean diet, and the results here provide motivation for further clinical interrogation of the antiaggregation properties of EVOO as a potential protective mechanism against AD.

Usefulness of the 1H NMR Multisuppression Approach for the Global Characterization of Monovarietal Extra-Virgin Olive Oils

Extra-virgin olive oil (EVOO) is one of the most appreciated vegetable oils worldwide, but its high price makes it prone to suffer adulteration with lower quality oils. Therefore, it is important to have methodologies able to study EVOO composition as a whole in a simple and fast way, in order to guarantee its quality and safety. For this purpose, in this study, commercial samples of five Spanish olive cultivars (Arbequina, Arroniz, Cornicabra, Hojiblanca, Picual) were studied by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, using standard and multisuppression pulses. The aim was to explore the possibility of 1H NMR use to characterize in a single run and in a global way the composition of these monocultivar oils, regarding not only their main components (fatty acids supported on triglycerides) but also minor ones (squalene, sterols, diterpenic wax esters of phytol and geranylgeraniol, phenolic and secoiridoid derivatives, like tyrosol, hydroxytyrosol, oleacein, oleocanthal, and lignans, among others, and aldehydes). The use of univariate and multivariate statistical analyses confirmed the presence of compositional features that were specific to some olive varieties. The Arbequina and Arroniz oils showed the most characteristic features that allowed for clearly differentiating them from the others. In contrast, the discrimination between the Cornicabra, Hojiblanca and Picual oils was not so easily achieved.

1-Acetoxypinoresinol, a Lignan from Olives: Insight into Its Characterization, Identification, and Nutraceutical Properties

Extra virgin olive oil (EVOO) is a symbol of the Mediterranean diet, constituting its primary source of fat. The beneficial effect of EVOO is strictly related to the presence of fatty acids and polyphenols, bioactive compounds endowed with nutraceutical properties. Among EVOO polyphenols, lignans possess a steroid-like chemical structure and are part of the phytoestrogen family, which is renowned for its health properties. The natural lignans (+)-pinoresinol and 1-acetoxypinoresinol (1-AP) are commonly present in olives and in EVOO. Although (+)-pinoresinol is found in different edible plants, such as flaxseed, beans, whole-grain cereals, sesame seeds, and certain vegetables and fruit, 1-AP was exclusively identified in olives in 2000. So far, the scientific literature has extensively covered different aspects of (+)-pinoresinol, including its isolation and nutraceutical properties. In contrast, less is known about the olive lignan 1-AP. Therefore, this review aimed to comprehensively evaluate the more important aspects of 1-AP, collecting all the literature from 2016 to the present, exploring its distribution in different cultivars, analytical isolation and purification, and nutraceutical properties.

EFSA Health Claims-Based Virgin Olive Oil Shelf-Life

The consumption of extra virgin olive oil (EVOO) has been linked to various health benefits, including a reduced risk of cardiovascular disease. EVOO contains triglycerides and unsaturated fatty acids, as well as minor compounds, such as polar phenols and tocopherols, which play a crucial nutritional and biological role. The composition of these minor compounds is affected by various factors that distinguish EVOOs from lower-quality olive oils. The European Parliament approved Regulation 1924/2006 that governs the use of health claims on food products based on EFSA reports. Currently, there are several authorized health claims related to unsaturated fatty acids, vitamin E, and polyphenol content that can be used for commercial reasons on EVOO labels. Consumers can easily take enough grams of EVOO per day to receive the beneficial effects of the nutrient in question; nevertheless, the use of these health claims is subject to a required concentration of specific nutrients throughout the shelf life of olive oil. Few studies have examined the evolution of these compounds along the shelf life of EVOO to meet health claims. This work aims to evaluate the nutritional profile of several EVOOs with potential health claims and the evolution of related nutrients during storage in darkness at different temperatures. This study proposes an accelerated method to determine the end of the EVOO shelf life based on the loss of its nutraceutical capacity and the inability to comply with the stated health claims.

Bio-phenols determination in olive oils: Recent mass spectrometry approaches

Extra virgin olive oil (EVOO) is largely used in Mediterranean diet, and it is also worldwide apprised not only for its organoleptic properties but also for its healthy effects mainly attributed to the presence of several naturally occurring phenolic and polyphenolic compounds (bio-phenols). These compounds are characterized by the presence of multiple phenolic groups in more or less complex structures. Their content is fundamental in defining the healthy qualities of EVOO and consequently the analytical methods for their characterization and quantification are of current interest. Traditionally their determination has been conducted using a colorimetric assay based on the reaction of Folin-Ciocalteu (FC) reagent with the functional hydroxy groups of phenolic compounds. Identification and quantification of the bio-phenols in olive oils requires certainly more performing analytical methods. Chromatographic separation is now commonly achieved by HPLC, coupled with spectrometric devices as UV, FID, and MS. This last approach constitutes an actual cutting-edge application for bio-phenol determination in complex matrices as olive oils, mostly on the light of the development of mass analyzers and the achievement of high resolution and accurate mass measurement in more affordable instrument configurations. After a short survey of some rugged techniques used for bio-phenols determination, in this review have been described the most recent mass spectrometry-based methods, adopted for the analysis of the bio-phenols in EVOOs. In particular, the sample handling and the results of HPLC coupled with low- and high-resolution MS and MS/MS analyzers, of ion mobility mass spectrometry and ambient mass spectrometry have been reported and discussed.

Elemane-Type Sesquiterpene, Acetonide Derived Polyacetylene and Other Constituents from the Whole Plant of Gymnanthemum theophrastifolium (Schweinf. ex Oliv. & Hiern) H.Rob. and Their Chemophenetic Significance

The chemical investigation of the methanol extract of the whole plant of Gymnanthemum theophrastifolium (Schweinf. ex Oliv. & Hiern) H.Rob. (Asteraceae) led to the isolation of a new elemane-type sesquiterpene (1), a new acetonide derived polyacetylene (2) and a naturally occurring compound (3) from the plant kingdom along with sixteen known compounds (4-19). Their structures were elucidated by extensive NMR and MS analysis. This is the first report on the chemical constituents of G. theophrastifolium. Furthermore, compounds 12, 13, and 14 are reported for the first time from the family Asteraceae, while compound 9 is reported for the first time from the genus Gymnanthemum. Thus, the present results provide valuable insights to the chemophenetic knowledge of G. theophrastifolium, which is also discussed in this work.

Phenolic Compounds from Virgin Olive Oil: Approaches for Their Synthesis and Analogues

Virgin olive oil (VOO) is the main fat consumed by populations in the Mediterranean basin, and phenolic compounds, minor components of this fat, are known to be responsible for diverse health benefits when consumed in a regular diet. According to numerous investigations, these benefits are mostly related to phenols such as tyrosol and hydroxytyrosol and secoiridoid derivatives such as ligstroside, oleuropein, oleocanthal and oleacein. These compounds are present in low concentrations, and for some of them, standards are not commercially available, hampering studies on the mechanisms underlying their biological activity. In order to contribute to a better knowledge of the bioactivity of these compounds and their metabolites, they must be available with high purity and in sufficient amounts for the assays. Chemical synthesis has been considered a convenient way to obtain these compounds. This Review will focus on the synthesis of representative VOO compounds, namely, ligstroside, oleuropein, oleocanthal, oleacein and analogues.

Separation and Determination of Biophenols in Olive Oil Samples Based on the Official Method of the International Olive Council and Commission Regulation (EU) No. 432/2012

The purpose of this study was to evaluate the key quality characteristics of olive oil with a main focus on the biophenolic content, its beneficial effects on health and the contribution of various quality characteristics to its health claims, as well as its influence from various parameters. Samples from different traditional oil-producing regions of Greece were initially examined for the most important quality parameters, such as the percentage of free acidity, the number of peroxides and the spectrophotometric investigation in the ultraviolet. The samples were then tested for their biophenolic content, expressed in milligrams of tyrosol, and its derivatives per 20 g of olive oil using the analytical technique high-performance liquid chromatography (HPLC). Then, the biophenol contents of the analyzed samples were compared based on the presented intensities in terms of the variety and the area of cultivation, the altitude, the type of cultivation, the extraction system in the mill and the time interval from olive harvest to oiling. Finally, according to the results, the content of biophenols in olive oil and its health claims were found to be influenced by the various parameters with which they were compared.

Evaluation of Selected Quality Parameters of “Agristigna” Monovarietal Extra Virgin Olive Oil and Its Apple Vinegar-Based Dressing during Storage

This study aimed to investigate the quality parameters and the oxidative stability (180 days of storage) of a water–oil emulsion formulated with Calabrian (Italy) monovarietal Agristigna extra virgin olive oil and apple vinegar. The best extra virgin olive oil/apple vinegar ratio was found to be 85/15 (v/v) and lecithin (2% w/v) was the best additive to reach proper stability and viscosity over time. An increase of lightness parameters was evidenced in both products in a storage time-dependent manner. During storage, both oil and dressing showed a free acidity level beyond the accepted limit for extra virgin olive oil, whereas a slight increase of the peroxide value was observed only for Glasoil at the end of the observation time without affecting sensory attributes. A general decrease of phytochemicals was observed for extra virgin olive oil and Glasoil, with different reduction trends and degrees depending on the chemical class. A lower stability of Glasoil during shelf-life was confirmed by the worsening of the rheological features and by the polyunsaturated fatty acids reduction (up to −21.71%) with a corresponding increase of the monounsaturated fatty acids/polyunsaturated fatty acids ratio (about +25.69%).

The impact of chitosan on the early metabolomic response of wheat to infection by Fusarium graminearum

BACKGROUND

Chitosan has shown potential for the control of Fusarium head blight (FHB) disease caused by Fusarium graminearum. The objective of this study was to compare the effect of chitosan hydrochloride applied pre- or post-fungal inoculation on FHB and to better understand its' mode of action via an untargeted metabolomics study.

RESULTS

Chitosan inhibited fungal growth in vitro and, when sprayed on the susceptible wheat cultivar Remus 24 hours pre-inoculation with F. graminearum, it significantly reduced the number of infected spikelets at 7, 14 and 21 days post-inoculation. Chitosan pre-treatment also increased the average grain weight per head, the number of grains per head and the 1000-grain weight compared to the controls sprayed with water. No significant impact of chitosan on grain yield was observed when the plants were sprayed 24 hours post-inoculation with F. graminearum, even if it did result in a reduced number of infected spikelets at every time point. An untargeted metabolomic study using UHPLC-QTOF-MS on wheat spikes revealed that spraying the spikes with both chitosan and F. graminearum activated known FHB resistance pathways (e.g. jasmonic acid). Additionally, more metabolites were up- or down-regulated when both chitosan and F. graminearum spores were sprayed on the spikes (117), as compared with chitosan (51) or F. graminearum on their own (32). This included a terpene, a terpenoid and a liminoid previously associated with FHB resistance.

CONCLUSIONS

In this study we showed that chitosan hydrochloride inhibited the spore germination and hyphal development of F. graminearum in vitro, triggered wheat resistance against infection by F. graminearum when used as a pre-inoculant, and highlighted metabolites and pathways commonly and differentially affected by chitosan, the pathogen and both agents. This study provides insights into how chitosan might provide protection or stimulate wheat resistance to infection by F. graminearum. It also unveiled new putatively identified metabolites that had not been listed in previous FHB or chitosan-related metabolomic studies.

Trapped Ion Mobility Incorporated in LC-HRMS Workflows as an Integral Analytical Platform of High Sensitivity: Targeted and Untargeted 4D-Metabolomics in Extra Virgin Olive Oil

Trapped ion mobility spectrometry (TIMS) is a promising technique for the separation of isomers based on their mobility. In the present work, TIMS coupled to liquid chromatography (LC) and high-resolution mass spectrometry (HRMS) was applied as a comprehensive analytical platform to address authenticity challenges, focusing on extra virgin olive oil (EVOO). Isomers detected in EVOO's phenolic fraction, classified into secoiridoids group, were successfully separated. Thanks to parallel accumulation serial fragmentation (PASEF) acquisition mode, high-quality spectra were obtained, facilitating identification. Moreover, a four-dimensional (4D) untargeted metabolomics approach was implemented to evaluate EVOO's global profile in cases of both variety and geographical origin discrimination. Potential authenticity markers, attributed to isomers, were successfully identified through the proposed workflow that incorporates ion mobility information along with LC-HRMS analytical evidence (i.e., mass accuracy, retention time, isotopic pattern, MS/MS fragmentation). Our study establishes LC-TIMS-HRMS in food authenticity and highlights mobility-enhanced metabolomics in four dimensions.

Geographical Characterization of Olive Oils from the North Aegean Region Based on the Analysis of Biophenols with UHPLC-QTOF-MS

Olive oil is famous due to the nutritional properties and beneficial health effects. The exceptional properties of virgin (VOO) and extra virgin olive oil (EVOO) are credited to the bioactive constituents of their polar fraction, the phenolic compounds. The concentration and composition of biophenols can be influenced by the geographical origin, the cultivar, as well as several agronomic and technological parameters. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole-time of flight tandem mass spectrometry (UHPLC-QTOF-MS) method was used to determine biophenols in Greek EVOOs from five islands originating from the North Aegean Region (Chios, Fournoi, Ikaria, Lesvos, and Samos) through target and suspect screening. In total, 14 suspect and 5 target compounds were determined in the analyzed EVOOs. The quantitative and semiquantitative results were compared to investigate discriminations between different regions. Significant differences were found between the islands based on the overall phenolic content and the concentration levels of individual compounds, as well. In the case of Lesvos, the territory was separated in subdivisions (zones), and each zone was studied individually.

Potential Effects of Phenolic Compounds That Can Be Found in Olive Oil on Wound Healing

The treatment of tissue damage produced by physical, chemical, or mechanical agents involves considerable direct and indirect costs to health care systems. Wound healing involves a series of molecular and cellular events aimed at repairing the defect in tissue integrity. These events can be favored by various natural agents, including the polyphenols in extra virgin olive oil (EVOO). The objective of this study was to review data on the potential effects of different phenolic compounds that can also be found in EVOO on wound healing and closure. Results of in vitro and animal studies demonstrate that polyphenols from different plant species, also present in EVOO, participate in different aspects of wound healing, accelerating this process through their anti-inflammatory, antioxidant, and antimicrobial properties and their stimulation of angiogenic activities required for granulation tissue formation and wound re-epithelialization. These results indicate the potential usefulness of EVOO phenolic compounds for wound treatment, either alone or in combination with other therapies. Human studies are warranted to verify this proposition.

Tunisian Olea europaea L. leaf extract suppresses Freund's complete adjuvant-induced rheumatoid arthritis and lipopolysaccharide-induced inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L. (olive) is traditionally used as a folk remedy and functional food in Europe and Mediterranean countries to treat inflammatory diseases. O. europaea contains phenolic compounds and have been reported to prevent cartilage degradation. However, the function and mechanism of O. europaea in rheumatoid arthritis are not known.

AIM OF THE STUDY

In this study, we aimed to examine anti-inflammatory and anti-arthritic effects of Tunisian O. europaea L. leaf ethanol extract (Oe-EE).

MATERIALS AND METHODS

To do this, we employed an in vitro macrophage-like cell line and an in vivo Freund's complete adjuvant (AIA)-induced arthritis model. Levels of inflammatory genes and mediators were determined from in vivo samples.

RESULTS

The Oe-EE clearly reduced the production of the lipopolysaccharide-mediated inflammatory mediators, nitric oxide (NO) and prostaglandin E₂ (PGE₂), in RAW264.7 cells. The results of HPLC showed that Oe-EE contained many active compounds such as oleuropein and flavonoids. In AIA-treated rats, swelling of paws, pain, and cartilage degeneration were alleviated by oral Oe-EE administration. Correlating with in vitro data, PGE₂ production was significantly reduced in paw samples. Furthermore, the molecular mechanism of Oe-EE was dissected, and Oe-EE regulated the gene expression of interleukin (IL)-6, inducible NO synthase (iNOS), and MMPs and inflammatory signaling activation.

CONCLUSION

Consequently, Oe-EE possesses anti-inflammatory and anti-rheumatic effects and is a potential effective treatment for rheumatoid arthritis.

Antioxidant quantification in different portions obtained during olive oil extraction process in an olive oil press mill

BACKGROUND

Different antioxidant compounds are generally transferred from olives to olive oil during the production process. This work characterized the principal total bioactive compounds (tocopherols and phenols) in olives, olive oil and by-products of four cultivars grown in Calabrian areas (southern Italy), considering the effect of harvesting period. Antioxidant capacity, total and individual phenolic compounds were also analysed.

RESULTS

Drupes, olive paste, pomace and olive wastewater showed similar phenolic compounds, while olive oil possessed a different composition, suggesting that phenols are not only transferred from drupe to oil, but also they change during oil production. Tocopherols varied among cultivars and harvesting period: generally, they were more abundant in samples produced in the first harvesting period. Qualitative and quantitative differences in phenolic composition and antioxidant activity were significantly found among cultivars in all the matrices.

CONCLUSION

The highest amount of total phenolic antioxidants ended up in olive wastewater with variability due to the olive cultivar, while only a small part of them finished in the oil. This work shows evidence that the availability of bioactive compounds in different portions from the olive oil extraction belong to different varietal origins. In particular, new information was acquired on Ottobratica Calipa, a new olive clone, that produced an olive oil with an interesting antioxidant amount. © 2020 Society of Chemical Industry.

Novel Treatments and Preventative Strategies Against Food-Poisoning Caused by Staphylococcal Species

Staphylococcal infections are a widespread cause of disease in humans. In particular, S. aureus is a major causative agent of infection in clinical medicine. In addition, these bacteria can produce a high number of staphylococcal enterotoxins (SE) that may cause food intoxications. Apart from S. aureus, many coagulase-negative Staphylococcus spp. could be the source of food contamination. Thus, there is an active research work focused on developing novel preventative interventions based on food supplements to reduce the impact of staphylococcal food poisoning. Interestingly, many plant-derived compounds, such as polyphenols, flavonoids, or terpenoids, show significant antimicrobial activity against staphylococci, and therefore these compounds could be crucial to reduce the incidence of food intoxication in humans. Here, we reviewed the most promising strategies developed to prevent staphylococcal food poisoning.

Anti-Inflammatory and Photoaging-Protective Effects of Olea europaea through Inhibition of AP-1 and NF-[Formula: see text] B Pathways

Olea europaea is a beneficial edible plant with a number of biological activities like anti-inflammatory, anti-oxidant, antithrombic, antihyperglycemic, and anti-ischemic activities. The mechanisms behind the antiphotoaging and anti-inflammatory effects of Olea europaea are not fully understood. To investigate how an ethanol extract of Olea europaea (Oe-EE) exerts these effects, we explored its activities in human keratinocytes and dermal fibroblasts. We assessed the anti-oxidant effects of Oe-EE via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2[Formula: see text]-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays and measured the expression levels of matrix metalloproteinases (MMPs), cyclooxygenase-2, interleukin (IL)-6, tumor necrosis factor (TNF)-[Formula: see text], and moisturizing factors. Antiphotoaging and anti-inflammatory mechanisms of Oe-EE were explored by assessing signaling molecule activation via immunoblotting. Oe-EE treatment decreased the mRNA expression level of MMPs, cyclooxygenase-2, IL-6, and TNF-[Formula: see text] and restored type I collagen, filaggrin, and sirtuin 1 expression in UVB-irradiated cells. Furthermore, Oe-EE inhibited the activities of several activator protein 1 regulatory enzymes, including extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK), and inhibited nuclear factor (NF)-[Formula: see text]B pathway signaling proteins. Therefore, our results indicate that Oe-EE has photoaging-protective and anti-inflammatory effects.

Evaluating Quality Parameters, the Metabolic Profile, and Other Typical Features of Selected Commercial Extra Virgin Olive Oils from Brazil

The production of extra virgin olive oil (EVOO) in Brazil developed quite recently, and information on commercial Brazilian EVOO's typical features is very scarce. In just one of the previously published works on Brazilian olive oil, the assessed samples were commercially available. In this study, a comprehensive characterization of EVOO samples acquired at local stores (at Rio de Janeiro and Rio Grande do Sul, from the two most prevalent cultivars, Arbequina and Koroneiki) was carried out considering the most relevant quality parameters, antioxidant capacity, oxidative stability, total phenolic content, fatty acid composition, and minor component metabolic profiling. The latter included: (1) the determination of individual phenolic compounds (belonging to four diverse chemical classes) and triterpenic acids by means of a powerful multi-class reversed-phase LC-MS method; (2) the quantitative profiling of tocopherols, phytosterols, and pigments by normal-phase LC-DAD/fluorescence; and (3) the quantitative appraisal of the volatile pattern of the oils by solid-phase microextraction (SPME)-gas chromatography (GC)-MS. By applying these methods, the concentrations of approximately 70 minor compounds were determined in commercial EVOOs from Brazil. To the best of our knowledge, the content of a very large number of phenolic compounds of those determined in the current report (mainly secoiridoids), the three triterpenic acids (maslinic, betulinic, and oleanolic acids), and the individual chlorophyll derivatives had not been previously evaluated in Brazilian EVOOs. The present work provides a broad picture of the compositional profile and other parameters of relevance of selected commercial Brazilian EVOOs available on local markets, describing their typicity and most particular features, some of which are known to have potential impacts on consumers' health.

Chemical Profile and Antibacterial Activity of a Novel Spanish Propolis with New Polyphenols also Found in Olive Oil and High Amounts of Flavonoids

Propolis is a natural product obtained from hives. Its chemical composition varies depending on the flora of its surroundings, but nevertheless, common for all types of propolis, they all exhibit remarkable biological activities. The aim of this study was to investigate the chemical composition and antimicrobial activity of a novel Spanish Ethanolic Extract of Propolis (SEEP). It was found that this new SEEP contains high amounts of polyphenols (205 ± 34 mg GAE/g), with unusually more than half of this of the flavonoid class (127 ± 19 mg QE/g). Moreover, a detailed analysis of its chemical composition revealed the presence of olive oil compounds (Vanillic acid, 1-Acetoxypinoresinol, p-HPEA-EA and 3,4-DHPEA-EDA) never detected before in propolis samples. Additionally, relatively high amounts of ferulic acid and quercetin were distinguished, both known for their important therapeutic benefits. Regarding the antimicrobial properties of SEEP, the minimal inhibitory and bactericidal concentrations (MIC and MBC) against Staphylococcus epidermidis strains were found at the concentrations of 240 and 480 µg/mL, respectively. Importantly, subinhibitory concentrations were also found to significantly decrease bacterial growth. Therefore, the results presented here uncover a new type of propolis rich in flavonoids with promising potential uses in different areas of human health.

A Metabolomics Coupled With Chemometrics Strategy to Filter Combinatorial Discriminatory Quality Markers of Crude and Salt-Fired Eucommiae Cortex

Eucommiae Cortex is commonly used for treating various diseases in a form of the crude and salt-fired products. Generally, it is empirical to distinguish the difference between two types of Eucommiae Cortex. The metabolomics coupled with chemometrics strategy was proposed to filter the combinatorial discriminatory quality markers for precise distinction and further quality control of the crude and salt-fired Eucommiae Cortex. The metabolomics data of multiple batches of Eucommiae Cortex samples was obtained by ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS). Orthogonal partial least-squares discriminant analysis was utilized to filter candidate markers for characterizing the obvious difference of the crude and salt-fired Eucommiae Cortex. The accuracy of combinatorial markers was validated by random forest and partial least squares regression. Finally, eleven combinatorial discriminatory quality markers from 67 identified compounds were rapidly screened, identified, and determined for distinguishing the difference between crude and salt-fired Eucommiae Cortex. It was demonstrated that UHPLC-MS based metabolomics with chemometrics was a powerful strategy to screen the combinatorial discriminatory quality markers for distinguishing the crude and salt-fired Eucommiae Cortex and to provide the reference for precise quality control of Eucommiae Cortex.

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil

Extra virgin olive oil (EVOO), a key component of the Mediterranean diet, has aroused interest in recent years due to its health properties. Nuclear magnetic resonance (NMR) spectroscopy is an appropriate tool for the accurate quantification of minor compounds in complex food matrices, such as polyphenols in olive oil. Flavonoids, lignans, secoiridoids and phenolic acids and alcohols in EVOO have been identified and quantified by NMR. This review provides an overview of the major developments in the structural elucidation of polyphenol compounds in EVOO. © 2019 Society of Chemical Industry.

Epigynumgenane-type pregnane glycosides from Epigynum cochinchinensis and their immunosuppressive activity

Five undescribed C₂₁ pregnane glycosides, epigycosides D-H, together with four known analogues, two lignans, and a flavonoid have been isolated from the stems of Epigynum cochinchinensis. The structures of pregnane glycosides were elucidated using spectroscopic techniques and acid hydrolysis. The in vitro immunological activities were assessed against Con A-stimulated proliferation of mice splenocytes. The C₂₁ pregnane glycosides showed immunosuppressive activity in a concentration-dependent manner. Moreover, epigycoside E exhibited a potent immunosuppressive effect, and the IC₅₀ value on Con A-stimulated mice splenocytes was 22.1 ± 6.4 μM. Epigycoside E also caused G₀/G₁ arrest, and inhibited TNF-α and IL-2 production.

The EFSA Health Claim on Olive Oil Polyphenols: Acid Hydrolysis Validation and Total Hydroxytyrosol and Tyrosol Determination in Italian Virgin Olive Oils

The health claims of olive oil represent an important marketing lever in raising the willingness to pay for a product, but world producers of extra virgin olive oil (EVOO) do not take advantage of it because there are still obstacles to their use. Among these, one issue is the lack of an official method for determination of all free and linked forms derived from secoiridoidic structures of hydroxytyrosol and tyrosol. In this study, different acidic hydrolytic procedures for analyzing the linked forms were tested. The best method was validated and then applied to more than 100 EVOOs. The content of oleuropein and ligstroside derivatives in EVOOs was indirectly evaluated comparing the amount of phenols before and after hydrolysis. After acidic hydrolysis, a high content of total tyrosol was found in most of the EVOOs. The use of a suitable corrective factor for the evaluation of hydroxytyrosol allows an accurate determination only using pure tyrosol as a standard. Further knowledge on the concentration of total hydroxytyrosol will assist in forecasting the resistance of oils against aging, its antioxidant potential and to better control its quality over time.

LC-DAD-ESI-MS/MS-based phenolic profiling and antioxidant activity in Turkish cv. Nizip Yaglik olive oils from different maturity olives

The current study was designed to find out how olive maturity indices (2.5, 3.5, and 4.5) affect the individual phenolic compounds and antioxidant potencies of olive oils produced from cv. Nizip Yaglik olives. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode was utilized for the determination of phenolic composition qualitatively and quantitatively. Findings asserted a quite similar phenolic profile (14 phenols) depending on the various phenolic groups in all oils, while the concentration of total and individual phenolic compounds revealed significant differences between the samples statistically (p < 0.05). Among the individual phenolic classes in all samples, secoiridoids were the most prevailing group and their total content showed a clear significant decline as the olive fruits get ripened. Antioxidant potency values showed a clear diminution attitude during the maturation of the olives. The principal component analysis revealed that oils were discriminated from each other according to phenolic compounds and antioxidant potencies. Moreover, oils obtained from the unripe and medium-ripe fruits possessed a very good quality marked by their elevated phenolic levels.

Olive pomace as a valuable source of bioactive compounds: A study regarding its lipid- and water-soluble components

Olive pomace is a major output of olive oil processing. This by-product is a valuable source of bioactive compounds with well-recognized benefits for human health and well-being. In this work, the proximate composition and the profiles of vitamin E (HPLC-DAD-FLD), fatty acids (GC-FID) and phenolics (HPLC-DAD-FL/MSⁿ) were determined. Additionally, a sustainable process for antioxidants extraction - Multi-frequency Multimode Modulated (MMM) ultrasonic technique - was compared to a conventional solid-liquid extraction. The total phenolics content and antioxidant activity (ferric reducing antioxidant power and DPPH scavenging ability) of the extracts were analysed to assess the efficacy of both extraction methodologies. The vitamin E profile of the olive pomace comprised the vitamers α-tocopherol, β-tocopherol, α-tocotrienol and γ-tocopherol. α-Tocopherol was the major form (2.63 mg/100 g), while the other vitamers were present in amounts lower than 0.1 mg/100 g. The lipid fraction was especially rich in oleic acid (75%), followed by palmitic (10%), linoleic (9%), and stearic (3%) acids. Hydroxytyrosol and comsegoloside represented ≈79% of the total phenolics present in olive pomace. Hydroxytyrosol content was 83.6 mg/100 g, while tyrosol was present in lower amounts (3.4 mg/100 g). Concerning the antioxidants extraction, the MMM technique allowed a faster and higher recovery (p < 0.05) of the compounds, compared to the conventional solid-liquid extraction. By this way, it seems to be a very promising eco-friendly and effective methodology to extract antioxidants from this and other matrices.

Current Disease-Targets for Oleocanthal as Promising Natural Therapeutic Agent

The broad number of health benefits which can be obtained from the long-term consumption of olive oil are attributed mainly to its phenolic fraction. Many olive oil phenolics have been studied deeply since their discovery due to their bioactivity properties, such as Hydroxytyrosol. Similarly, in the last decade, the special attention of researchers has been addressed to Oleocanthal (OC). This olive oil phenolic compound has recently emerged as a potential therapeutic agent against a variety of diseases, including cancer, inflammation, and neurodegenerative and cardiovascular diseases. Recently, different underlying mechanisms of OC against these diseases have been explored. This review summarizes the current literature on OC to date, and focuses on its promising bioactivities against different disease-targets.

Chemical Constituents of the Seed Cake of Camellia oleifera and Their Antioxidant and Antimelanogenic Activities

There is a growing interest in the exploitation of agricultural byproducts. This study explored the potential beneficial health effects from the main biowaste, tea seed pomace of Camellia oleifera Abel (Theaceae), produced when tea seed is processed. Eighteen compounds were isolated from the 70% EtOH extract of the seed cake of C. oleifera. Their structures were determined by ESI-MS, ¹ H- and ¹³ C-NMR together with literature data. All fractions and compounds were evaluated for the antioxidant and melanogenesis inhibitory activities. As the result, AcOEt fraction has the best in vitro antioxidant and antimelanogenesis activities, compounds 7 - 12 and 15 showed remarkable antioxidant activity, compounds 4, 6, 8, and 15 - 17 exhibited superior inhibitory activities against melanogenesis. Furthermore, tyrosinase inhibitory activity assay suggested that compound 8 could suppress melanogenesis by inhibiting the expression of tyrosinase.

Critical Review on the Significance of Olive Phytochemicals in Plant Physiology and Human Health

Olive oil displays remarkable organoleptic and nutritional features, which turn it into a foodstuff appreciated by consumers, and a basic component of the Mediterranean diet. Indeed, the noticed benefits of including olive oil in the diet have been assigned to the presence of diverse bioactive compounds with different molecular structures. These compounds confer a wide range of biological properties to this food matrix, including the prevention of distinct human diseases as well as the modulation of their severity. The most relevant bioactive compounds present in olive oil correspond to benzoic and cinnamic acids, phenolic alcohols and secoiridoids, and also flavonoids. Over the last decades, several studies, devoted to gaining a further insight into the relative contribution of the separate groups and individual compounds for their biological activities, have been conducted, providing relevant information on structure-activity relationships. Therefore, this paper critically reviews the health benefits evidenced by distinct phenolic compounds found in olive oils, thus contributing to clarify the relationship between their chemical structures and biological functions, further supporting their interest as essential ingredients of wholesome foods.

The Compounds Responsible for the Sensory Profile in Monovarietal Virgin Olive Oils

Monovarietal virgin olive oils (VOOs) are very effective to study relationships among sensory attributes, the compounds responsible for flavour, and factors affecting them. The stimulation of the human sensory receptors by volatile and non-volatile compounds present in monovarietal virgin olive oils gives rise to the sensory attributes that describe their peculiar delicate and fragrant flavours. The formation of these compounds is briefly illustrated and the influence of the agronomic and technological factors that affect their concentrations in the oil is examined. The relationships between compounds responsible for the olive oil flavour and sensory attributes are discussed. Several approaches for the varietal differentiation of monovarietal virgin olive oils are also overviewed.

Phenolic Compounds Profiling of Virgin Olive Oils from Different Varieties Cultivated in Mendoza, Argentina, by Using Liquid Chromatography-Mass Spectrometry

The aim of this work was to achieve a preliminary characterization of the profile of the phenolic fraction of virgin olive oils (VOOs) from Maipú (Mendoza, Argentina). Thus, 25 commercial VOO samples from Arauco, Arbequina, Picual, Frantoio, Changlot, Empeltre, Nevadillo, Manzanilla, and Coratina (both monovarietals and blends) were analyzed using LC-ESI-QTOF MS and LC-ESI-IT MS for identification and quantification purposes, respectively. A rapid LC method (15 min) accomplished quantitative information about a total of 40 phenolic compounds, including secoiridoid derivatives, which have not been evaluated before in samples coming from the subregion so-called Maipú (Mendoza province, Argentina). The results make evident that olive oils coming from Mendoza can be considered as important sources of phenolic bioactive compounds, exhibiting similar phenolic compound levels to those shown by oils from other typical world production regions. Moreover, some distinctive features of the Arauco variety (Argentinean autochthonous variety) were pointed out; indeed, a correlation between flavonoids content and botanical variety was established herewith.

Engineering design and prototype development of a full scale ultrasound system for virgin olive oil by means of numerical and experimental analysis

The aim of the virgin olive oil extraction process is mainly to obtain the best quality oil from fruits, by only applying mechanical actions while guaranteeing the highest overall efficiency. Currently, the mechanical methods used to extract virgin oils from olives are basically of two types: the discontinuous system (obsolete) and the continuous one. Anyway the system defined as "continuous" is composed of several steps which are not all completely continuous, due to the presence of the malaxer, a device that works in batch. The aim of the paper was to design, realize and test the first full scale sono-exchanger for the virgin olive oil industry, to be placed immediately after the crusher and before the malaxer. The innovative device is mainly composed of a triple concentric pipe heat exchanger combined with three ultrasound probes. This mechanical solution allows both the cell walls (which release the oil droplets) along with the minor compounds to be destroyed more effectively and the heat exchange between the olive paste and the process water to be accelerated. This strategy represents the first step towards the transformation of the malaxing step from a batch operation into a real continuous process, thus improving the working capacity of the industrial plants. Considering the heterogeneity of the olive paste, which is composed of different tissues, the design of the sono-exchanger required a thorough fluid dynamic analysis. The thermal effects of the sono-exchanger were monitored by measuring the temperature of the product at the inlet and the outlet of the device; in addition, the measurement of the pigments concentration in the product allowed monitoring the mechanical effects of the sono-exchanger. The effects of the innovative process were also evaluated in terms of extra virgin olive oil yields and quality, evaluating the main legal parameters, the polyphenol and tocopherol content. Moreover, the activity of the polyphenol oxidase enzyme in the olive paste was measured.

From Olive Fruits to Olive Oil: Phenolic Compound Transfer in Six Different Olive Cultivars Grown under the Same Agronomical Conditions

Phenolic compounds are responsible of the nutritional and sensory quality of extra-virgin olive oil (EVOO). The composition of phenolic compounds in EVOO is related to the initial content of phenolic compounds in the olive-fruit tissues and the activity of enzymes acting on these compounds during the industrial process to produce the oil. In this work, the phenolic composition was studied in six major cultivars grown in the same orchard under the same agronomical and environmental conditions in an effort to test the effects of cultivars on phenolic composition in fruits and oils as well as on transfer between matrices. The phenolic fractions were identified and quantified using high-performance liquid chromatography-diode array detector-time-of-flight-mass spectrometry. A total of 33 phenolic compounds were determined in the fruit samples and a total of 20 compounds in their corresponding oils. Qualitative and quantitative differences in phenolic composition were found among cultivars in both matrices, as well as regarding the transfer rate of phenolic compounds from fruits to oil. The results also varied according to the different phenolic groups evaluated, with secoiridoids registering the highest transfer rates from fruits to oils. Moreover, wide-ranging differences have been noticed between cultivars for the transfer rates of secoiridoids (4.36%–65.63% of total transfer rate) and for flavonoids (0.18%–0.67% of total transfer rate). ‘Picual’ was the cultivar that transferred secoiridoids to oil at the highest rate, whereas ‘Changlot Real’ was the cultivar that transferred flavonoids at the highest rates instead. Principal-component analysis confirmed a strong genetic effect on the basis of the phenolic profile both in the olive fruits and in the oils.

Extraction, Separation, and Identification of Phenolic Compounds in Virgin Olive Oil by HPLC-DAD and HPLC-MS

The aim of this study was to evaluate the recovery of individual phenolic compounds extracted from virgin olive oil (VOO), from different Greek olive varieties. Sufficient recoveries (90%) of all individual phenolic compounds were obtained using methanol as an extraction solvent, acetonitrile for residue solubilization, and two washing steps with hexane. Moreover, in order to elucidate structural characteristics of phenolic compounds in VOO, high performance liquid chromatography with a diode array detector (HPLC-DAD) at 280 and 340 nm and HPLC coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) in the negative-ion mode were performed. The most abundant phenolic compounds were oleuropein derivatives with m/z 319 and 377 and ligstroside derivatives with m/z 303, 361. Lignans, such as 1-acetoxypinoresinol and pinoresinol were also present in substantial quantities in the phenolic fraction. However, pinoresinol was co-eluted with dialdehydic form of ligstroside aglycone (DAFLA) and it was not possible to be quantified separately. The phenolic extracts, obtained from different VOO samples, yielded similar HPLC profiles. Differences, however, were observed in the last part of the chromatogram, corresponding to isomers of the aldehydic form of ligstroside aglycone. Oxidized phenolic products, originating from secoiridoids, were also detected.