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Antioxidants
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Olive Antioxidants: Extraction, Biological Activity and Practical Applications
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Olive Antioxidants: Extraction, Biological Activity and Practical Applications

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Natural and Synthetic Antioxidants".

Deadline for manuscript submissions: closed (31 May 2022) | Viewed by 51926

Special Issue Editors

Prof. Dr. Juan Fernández-Bolaños

E-Mail Website
Guest Editor
Department of Food Phytochemistry, Fat Institute, The Spanish National Research Council (CSIC), Pablo de Olavide University Campus - Building 46, 41013 Seville, Spain
Interests: food analysis; bioactive molecules; alperujo; phenolic compounds; extraction processes; phenol–polysaccharide complex; modified pectin; antioxidant activities; anti-inflammatory activity
Special Issues, Collections and Topics in MDPI journals
Dr. Alejandra Bermudez-Oria

E-Mail Website
Guest Editor
Department of Food Phytochemistry, Fat Institute, The Spanish National Research Council (CSIC), Pablo de Olavide University Campus - Building 46, 41013 Seville, Spain
Interests: bioactive molecules; alperujo; extraction processes; phenol–polysaccharide complex; antioxidant dietary fiber; phenolic compounds; modified pectin; flow cytometry; antiproliferative activity; anti-inflammatory activity; cancer
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Olive extracts obtained from oil, fruit, leaves, wood, or waste are responsible for many health benefits, such as the reduction of hypertension and diabetes or the prevention of cardiovascular diseases and cancer. These effects are due, at least in part, to the high amount of antioxidants present in olive products, especially polyphenols (phenolic acid, flavonoids, lignans, secoiridoids derivatives), carotenoids (xanthophyll and β-carotene), chlorophylls, pheophytins, and tocopherol α (vitamin E), since they ameliorate the oxidative stress produced by free radicals and subsequently cellular damage. In recent years, studies have also focused on cell wall polysaccharides-polyphenols complexes that occur during crushing and malaxation of the olive paste before the extraction of the oil, containing nutritional, health, and antioxidant benefits. Thus, olive extracts have received considerable attention and have been increasingly investigated in relation to health effects, analytical approaches, extraction efficiency, and applications. We invite you to contribute your latest findings to this Special Issue that will include all aspects of the extracts from olive material; papers including the development and optimization of new extraction procedures from conventional extraction methods with solvent systems (hot water, organic solvents, maceration, Soxhlet extraction,) to green non-conventional methods (deep eutectic solvent, ultrasound-, microwave-, enzymatic-assisted extraction, supercritical fluid, subcritical water extraction, or pressurized liquid extraction). This information could be complemented with recent developments in the application of these extracts in the cosmetic, pharmaceutical, and food industries.

Prof. Dr. Juan Fernández-Bolaños
Dr. Alejandra Bermudez-Oria
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antioxidants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Antioxidant effect
  • Olive oil
  • Olive by-products
  • Olive leaves
  • Polyphenols
  • Carotenoids
  • Polysaccharides-polyphenols complexes
  • Vitamin E
  • Health
  • Mediterranean diet

Published Papers (22 papers)

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Research

12 pages, 2048 KiB  
Article
Ozonated Olive Oil: Enhanced Cutaneous Delivery via Niosomal Nanovesicles for Melanoma Treatment
by Sherif Ashraf Fahmy, Asmaa Ramzy, Amany M. Sawy, Mohamed Nabil, Mohamed Z. Gad, Mohamed El-Shazly, Mourad A. M. Aboul-Soud and Hassan Mohamed El-Said Azzazy
Antioxidants 2022, 11(7), 1318; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11071318 - 04 Jul 2022
Cited by 21 | Viewed by 2659
Abstract
Ozonated olive oil (OL) combines the therapeutic effects of both ozone and olive oil. However, it suffers from limited water solubility and poor transdermal permeation, which hinder its application in melanoma treatment. Nanocarrier host molecules, such as niosomes, were used to improve the [...] Read more.
Ozonated olive oil (OL) combines the therapeutic effects of both ozone and olive oil. However, it suffers from limited water solubility and poor transdermal permeation, which hinder its application in melanoma treatment. Nanocarrier host molecules, such as niosomes, were used to improve the water solubility, transdermal permeation, and anticancer effect of hydrophobic compounds. This study aims to design and optimize a niosomal vesicular nanoplatform loaded with OL (OL/NSs) to improve OL’s skin permeation and anti-melanoma effect. In this regard, OL was prepared and characterized by evaluating its chemical properties (acid, peroxide, and iodine values) and fatty acid composition using gas chromatography. Then, OL/NSs were developed using the thin film hydration method employing cholesterol, Span 60, and Tween 60 at five different molar ratios. The optimized niosomes had an average diameter of 125.34 ± 13.29 nm, a surface charge of −11.34 ± 4.71 mV, and a spherical shape. They could entrap 87.30 ± 4.95% of the OL. OL/NSs showed a 75% sustained oil release over 24 h. The skin permeation percentage of OL/NSs was 36.78 ± 3.31 and 53.44 ± 6.41% at 12 and 24 h, respectively, three times higher than that of the free OL (11.50 ± 1.3 and 17.24 ± 2.06%, at 12 and 24 h, respectively). Additionally, the anticancer activity of the developed niosmal formulation, when tested on human melanoma cells (A375), was double that of the free OL; the IC50 of the OL/NSs was 8.63 ± 2.8 μg/mL, and that of the free OL was 17.4 ± 3.7 μg/mL. In conclusion, the encapsulation of ozonated olive oil in niosomes enhanced its water solubility, skin permeation, and anticancer activity and thus may represent potent natural chemotherapy in treating melanoma. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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22 pages, 1411 KiB  
Article
Singular Olive Oils from a Recently Discovered Spanish North-Western Cultivar: An Exhaustive 3-Year Study of Their Chemical Composition and In-Vitro Antidiabetic Potential
by María Figueiredo-González, Lucía Olmo-García, Patricia Reboredo-Rodríguez, Irene Serrano-García, Glenda Leuyacc-del Carpio, Beatriz Cancho-Grande, Alegría Carrasco-Pancorbo and Carmen González-Barreiro
Antioxidants 2022, 11(7), 1233; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11071233 - 23 Jun 2022
Cited by 3 | Viewed by 1501
Abstract
In this work, the quality and physicochemical parameters, phenolic composition, and antidiabetic potential of olive oils obtained from olives belonging to centenarian olive trees of the so-called ‘Mansa de Figueiredo’ cultivar were evaluated during three consecutive crop seasons (2017–2019). The oils produced during [...] Read more.
In this work, the quality and physicochemical parameters, phenolic composition, and antidiabetic potential of olive oils obtained from olives belonging to centenarian olive trees of the so-called ‘Mansa de Figueiredo’ cultivar were evaluated during three consecutive crop seasons (2017–2019). The oils produced during the three crop years were classified as extra virgin based on the quality-related indices, sensory analysis, and the genuineness-related parameters. In addition, LC-ESI-TOF MS was used to get a comprehensive characterisation of the phenolic fraction while LC-ESI-IT MS was applied for quantitation purposes. The content of phenolic compounds (ranging from 1837 to 2434 mg/kg) was significantly affected by the harvest year due to the environmental conditions and ripening index. Furthermore, although significant differences in the inhibitory effects against the α-glucosidase enzyme for the EVOOs extracted throughout the three successive years were detected, all the studied EVOOs exhibited a stronger inhibitor effect than that found for acarbose. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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20 pages, 5146 KiB  
Article
Screening of the Supercritical Impregnation of Olea europaea Leaves Extract into Filaments of Thermoplastic Polyurethane (TPU) and Polylactic Acid (PLA) Intended for Biomedical Applications
by Noelia D. Machado, Cristina Cejudo-Bastante, María L. Goñi, Nicolás A. Gañán, Lourdes Casas-Cardoso and Casimiro Mantell-Serrano
Antioxidants 2022, 11(6), 1170; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11061170 - 14 Jun 2022
Cited by 5 | Viewed by 1804
Abstract
The leaves of Olea europaea as agricultural waste represent a convenient source of antioxidants. In combination with supercritical CO2 (scCO2), assisted impregnation is an interesting strategy for the preparation of biomedical devices with specific bioactivity. For this purpose, 3D-printable filaments [...] Read more.
The leaves of Olea europaea as agricultural waste represent a convenient source of antioxidants. In combination with supercritical CO2 (scCO2), assisted impregnation is an interesting strategy for the preparation of biomedical devices with specific bioactivity. For this purpose, 3D-printable filaments of thermoplastic polyurethane (TPU) and polylactic acid (PLA) were employed for the supercritical impregnation of ethanolic olive leaves extract (OLE) for biomedical application. The extraction of OLE was performed using pressurized liquids. The effect of pressure (100–400 bar), temperature (35–55 °C), and the polymer type on the OLE impregnation and the swelling degree were studied including a morphological analysis and the measurement of the final antioxidant activity. All the studied variables as well as their interactions showed significant effects on the OLE loading. Higher temperatures favored the OLE loading while the pressure presented opposite effects at values higher than 250 bar. Thus, the highest OLE loadings were achieved at 250 bar and 55 °C for both polymers. However, TPU showed c.a. 4 times higher OLE loading and antioxidant activity in comparison with PLA at the optimal conditions. To the best of our knowledge, this is the first report using TPU for the supercritical impregnation of a natural extract with bioactivity. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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15 pages, 2497 KiB  
Article
Valorization and Potential Antimicrobial Use of Olive Mill Wastewater (OMW) from Italian Olive Oil Production
by Eleonora Russo, Andrea Spallarossa, Antonio Comite, Marcello Pagliero, Patrizia Guida, Vittorio Belotti, Debora Caviglia and Anna Maria Schito
Antioxidants 2022, 11(5), 903; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11050903 - 04 May 2022
Cited by 13 | Viewed by 3068
Abstract
The production of olive oil generates olive mill wastewater (OMW) which essentially derives from the processing, treatment and pressing of olives in mills. Traditional milling processes require a quantity of water varying between 40 and 120 L per quintal of pressed olives, generating [...] Read more.
The production of olive oil generates olive mill wastewater (OMW) which essentially derives from the processing, treatment and pressing of olives in mills. Traditional milling processes require a quantity of water varying between 40 and 120 L per quintal of pressed olives, generating a considerable amount of wastewater. It is thus necessary to reduce process water and enhance its use to implement the concept of a circular economy. To this end, our preliminary work was dedicated to water purification by means of suitable and efficient filtration systems. The microfiltered OMW was firstly concentrated through reverse osmosis. Then, an additional concentration step was carried out via vacuum membrane distillation using hydrophobic hollow fiber membranes. The application of the membrane-based processes allowed the recovery of a purified water and the concentration of valuable polyphenols in a smaller volume. The different fractions obtained from the purification have been tested for the determination of the antioxidant power (DPPH assay) and dosage of polyphenols (Folin–Ciocalteu assay) and were characterized using IR spectroscopy. All samples showed relevant antioxidant activity (percentage range: 10–80%) and total phenolic content in the 1.5–15 g GAE/L range. The obtained fractions were tested for their antimicrobial effect on numerous clinical isolates of Gram-positive and Gram-negative species, resistant and multi-resistant to current antibiotic drugs. OMW samples showed widespread activity against the considered (phyto)pathogens (MIC range 8–16 mg/mL) thus supporting the value of this waste material in the (phyto)pharmaceutical field. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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19 pages, 2221 KiB  
Article
The Impact of Mild Frost Occurring at Different Harvesting Times on the Volatile and Phenolic Composition of Virgin Olive Oil
by Catalina Pino, Betsabet Sepúlveda, Francisco Tapia, Jorge Saavedra, Diego L. García-González and Nalda Romero
Antioxidants 2022, 11(5), 852; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11050852 - 27 Apr 2022
Cited by 6 | Viewed by 1777
Abstract
The organoleptic characteristics of virgin olive oil (VOO), together with its nutritional and health properties, have led the olive tree to be cultivated beyond the Mediterranean basin, reaching latitudes with colder climates, with minimum temperatures below 0 °C and with a higher probability [...] Read more.
The organoleptic characteristics of virgin olive oil (VOO), together with its nutritional and health properties, have led the olive tree to be cultivated beyond the Mediterranean basin, reaching latitudes with colder climates, with minimum temperatures below 0 °C and with a higher probability of early frosts. The freezing of olives generates destruction within the tissues and promotes degradation reactions. In this study, the impact of mild frost occurring at different harvesting times on the composition of volatiles and phenolic compounds in VOO were investigated. Arbequina variety olives were harvested at different stages of ripening. Half of the olives were subjected to oil extraction and the other half were frozen at −3 ± 1 °C for 12 h prior to oil extraction. A significant decrease of phenolic compounds with harvesting time was observed in both types of oils (fresh and frozen olives). Oils from frozen olives presented a slightly higher content of total phenols, except in the advanced ripening stage (September), and a slightly lower content of volatile compounds at all harvesting times. In addition, a higher content of 3,4-DHPEA-EDA was observed in oils from frozen olives, which is attributed to an early action of the endogenous β-glucosidase enzyme on oleuropein in freeze-damaged olive fruits. Principal component analysis and Discriminant Partial Least Square Regression allowed the oils to be classified according to the type of fruit (fresh and frozen) and the month of harvest. This study would indicate that mild frost would have a low impact on the chemical composition of virgin olive oil, although, this depends on the ripening stage. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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22 pages, 3100 KiB  
Article
Polyphenols Extracts from Oil Production Waste Products (OPWPs) Reduce Cell Viability and Exert Anti-Inflammatory Activity via PPARγ Induction in Colorectal Cancer Cells
by Manuela Leo, Livio Muccillo, Laura Dugo, Roberta Bernini, Luca Santi and Lina Sabatino
Antioxidants 2022, 11(4), 624; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11040624 - 24 Mar 2022
Cited by 10 | Viewed by 2168
Abstract
Olive oil production is associated with the generation of oil production waste products (OPWPs) rich in water-soluble polyphenols that represent serious environmental problems. Yet OPWPs can offer new opportunities by exploiting their bioactive properties. In this study, we chemically characterized OPWPs polyphenolic extracts [...] Read more.
Olive oil production is associated with the generation of oil production waste products (OPWPs) rich in water-soluble polyphenols that represent serious environmental problems. Yet OPWPs can offer new opportunities by exploiting their bioactive properties. In this study, we chemically characterized OPWPs polyphenolic extracts and investigated their biological activities in normal and colorectal cancer cells. Hydroxytyrosol (HTyr), the major constituent of these extracts, was used as the control. We show that both HTyr and the extracts affect cell viability by inducing apoptosis and cell cycle arrest. They downregulate inflammation by impairing NF-κB phosphorylation and expression of responsive cytokine genes, as TNF-α and IL-8, at both mRNA and protein levels, and prevent any further increase elicited by external challenges. Mechanistically, HTyr and the extracts activate PPARγ while hampering pro-inflammatory genes expression, acting as a specific agonist, likely through a trans-repression process. Altogether, OPWPs polyphenolic extracts show stronger effects than HTyr, conceivably due to additive or synergistic effects of all polyphenols contained. They display anti-inflammatory properties and these results may pave the way for improving OPWPs extraction and enrichment methods to reduce the environmental impact and support their use to ameliorate the inflammation associated with diseases and tumors. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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19 pages, 1159 KiB  
Article
Effects of Erythrodiol on the Antioxidant Response and Proteome of HepG2 Cells
by Juan Luis Peñas-Fuentes, Eva Siles, Eva E. Rufino-Palomares, Amalia Pérez-Jiménez, Fernando J. Reyes-Zurita, José A. Lupiáñez, Carlos Fuentes-Almagro and Juan Peragón-Sánchez
Antioxidants 2022, 11(1), 73; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11010073 - 29 Dec 2021
Cited by 3 | Viewed by 1620
Abstract
Erythrodiol (EO) is a pentacyclic triterpenic alcohol found in olive tree leaves and olive oil, and it has important effects on the health properties and quality of olive oil. In this study, we characterized the cytotoxic effects of EO on human hepatocarcinoma (HepG2) [...] Read more.
Erythrodiol (EO) is a pentacyclic triterpenic alcohol found in olive tree leaves and olive oil, and it has important effects on the health properties and quality of olive oil. In this study, we characterized the cytotoxic effects of EO on human hepatocarcinoma (HepG2) cells by studying changes in cell viability, reactive oxygen species (ROS) production, antioxidant defense systems, and the proteome. The results reveal that EO markedly decreased HepG2 cell viability without changing ROS levels. The concentrations of glutathione and NADPH were significantly reduced, with selective changes in the activity of several antioxidant enzymes: glutathione peroxidase, glutathione reductase, glucose 6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. Proteomic data reveal that EO led to the complete elimination or decreased abundance of 41 and 3 proteins, respectively, and the abundance of 29 proteins increased. The results of functional enrichment analysis show that important metabolic processes and the nuclear transport of mature mRNA were impaired, whereas AMP biosynthesis and cell cycle G2/M phase transition were induced. The transcription factors and miRNAs involved in this response were also identified. These potent antiproliferative effects make EO a good candidate for the further analysis of its hepatic antitumor effects in in vivo studies. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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14 pages, 324 KiB  
Article
Olive-Leaf Extracts Modulate Inflammation and Oxidative Stress Associated with Human H. pylori Infection
by Jose Manuel Silvan, Esperanza Guerrero-Hurtado, Alba Gutiérrez-Docio, Teresa Alarcón-Cavero, Marin Prodanov and Adolfo J. Martinez-Rodriguez
Antioxidants 2021, 10(12), 2030; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10122030 - 20 Dec 2021
Cited by 11 | Viewed by 3974
Abstract
Helicobacter pylori (H. pylori) is one of the major human pathogens and the main cause of pathological damages that can progress from chronic gastritis to gastric cancer. During the colonization of gastric mucosa, this bacterium provokes a strong inflammatory response and [...] Read more.
Helicobacter pylori (H. pylori) is one of the major human pathogens and the main cause of pathological damages that can progress from chronic gastritis to gastric cancer. During the colonization of gastric mucosa, this bacterium provokes a strong inflammatory response and subsequent oxidative process, which are associated with tissue damage. Therefore, the objective of this research was to evaluate the ability of two olive-leaf extracts (E1 and E2) to modulate the inflammatory response and oxidative stress in H. pylori-infected human gastric AGS cells. The obtained results showed that both extracts significantly decreased interleukin-8 (IL-8) secretion and reactive oxygen species (ROS) production in human gastric AGS cells. Both extracts also showed antibacterial activity against different H. pylori strains. HPLC-PAD-MS characterization demonstrated that extract E1 was mainly composed of highly hydrophilic compounds, such as hydroxytyrosol (HT) and its glucosides, and it was the most effective extract as an antibacterial agent. In contrast, extract E2 was composed mostly of moderately hydrophilic compounds, such as oleuropein (OLE), and it was more effective than extract E1 as an anti-inflammatory agent. Both extracts exhibited similar potential to decrease ROS production. These results show the importance of standardizing the extract composition according to the bioactive properties that should be potentiated. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
12 pages, 463 KiB  
Article
Synergistic Effect of 3′,4′-Dihidroxifenilglicol and Hydroxytyrosol on Oxidative and Nitrosative Stress and Some Cardiovascular Biomarkers in an Experimental Model of Type 1 Diabetes Mellitus
by José Pedro De La Cruz Cortés, Leticia Vallejo-Carmona, María Monsalud Arrebola, Esther Martín-Aurioles, María Dolores Rodriguez-Pérez, Laura Ortega-Hombrados, Cristina Verdugo, María África Fernández-Prior, Alejandra Bermúdez-Oria and José Antonio González-Correa
Antioxidants 2021, 10(12), 1983; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121983 - 13 Dec 2021
Cited by 5 | Viewed by 2228
Abstract
The objective of this study was to assess a possible synergistic effect of two extra-virgin olive oil polyphenols, 3,4,-dyhydroxyphenylglycol (DHPG) and hydroxytyrosol (HT), in an experimental model of type 1 diabetes. Seven groups of animals were studied: (1) Nondiabetic rats (NDR), (2) 2-month-old [...] Read more.
The objective of this study was to assess a possible synergistic effect of two extra-virgin olive oil polyphenols, 3,4,-dyhydroxyphenylglycol (DHPG) and hydroxytyrosol (HT), in an experimental model of type 1 diabetes. Seven groups of animals were studied: (1) Nondiabetic rats (NDR), (2) 2-month-old diabetic rats (DR), (3) DR treated with 5 mg/kg/day p.o. HT, (4) DR treated with 0.5 mg/kg/day p.o. DHPG, (5) DR treated with 1 mg/kg/day p.o. DHPG, (6) DR treated with HT + DHPG (0.5), (7) DR treated with HT + DHPG (1). Oxidative stress variables (lipid peroxidation, glutathione, total antioxidant activity, 8-isoprostanes, 8-hydroxy-2-deoxyguanosine, and oxidized LDL), nitrosative stress (3-nitrotyrosine), and some cardiovascular biomarkers (platelet aggregation, thromboxane B2, prostacyclin, myeloperoxidase, and vascular cell adhesion protein 1 (VCAM-1)) were analyzed. The diabetic animals showed an imbalance in all of the analyzed variables. HT exerted an antioxidant and downregulatory effect on prothrombotic biomarkers while reducing the fall of prostacyclin. DHPG presented a similar, but quantitatively lower, profile. HT plus DHPG showed a synergistic effect in the reduction of oxidative and nitrosative stress, platelet aggregation, production of prostacyclin, myeloperoxidase, and VCAM-1. This synergism could be important for the development of functional oils enriched in these two polyphenols in the proportion used in this study. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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22 pages, 1178 KiB  
Article
Improved Oxidative Stability and Sensory Quality of Beef Hamburgers Enriched with a Phenolic Extract from Olive Vegetation Water
by Sara Barbieri, Dario Mercatante, Stefania Balzan, Sonia Esposto, Vladimiro Cardenia, Maurizio Servili, Enrico Novelli, Agnese Taticchi and Maria Teresa Rodriguez-Estrada
Antioxidants 2021, 10(12), 1969; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121969 - 09 Dec 2021
Cited by 15 | Viewed by 2477
Abstract
This study aims at evaluating the effect of a phenol-rich extract obtained from the concentration and purification of olive mill wastewaters (added at a ratio of 87.5 and 175 mg of phenols/kg meat) on the stability and sensory quality of beef hamburgers packed [...] Read more.
This study aims at evaluating the effect of a phenol-rich extract obtained from the concentration and purification of olive mill wastewaters (added at a ratio of 87.5 and 175 mg of phenols/kg meat) on the stability and sensory quality of beef hamburgers packed under modified atmosphere and stored under alternating exposure to fluorescent light at 4 ± 2 °C for 9 days. The hamburgers were sampled at different times (0, 6, and 9 days) and grilled at 200 °C. After 9 days, more than 56% of the added phenols in the raw burgers and more than 20% the grilled ones were retained. The results show that both concentrations of phenolic extract proved to effectively reduce primary and secondary lipid oxidation, as well as cholesterol oxidation products (COPs), during the shelf-life of raw hamburgers. Peroxide value, thiobarbituric acid reactive substances, and total COPs were up to 1.4-, 4.5-, and 8.8-fold lower in phenol-enriched raw hamburgers, respectively, than in the control samples; a similar trend was noted also in phenol-enriched cooked hamburgers (1.3-, 5.7-, and 4-fold lower). The sensory analysis also confirmed the effectiveness of the addition of phenolic extract, resulting in a positive effect on the red color intensity (raw product) and thus reducing browning during storage. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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11 pages, 1393 KiB  
Article
Oleuropein Degradation Kinetics in Olive Leaf and Its Aqueous Extracts
by María Esther Martínez-Navarro, Cristina Cebrián-Tarancón, José Oliva, María Rosario Salinas and Gonzalo L. Alonso
Antioxidants 2021, 10(12), 1963; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121963 - 08 Dec 2021
Cited by 12 | Viewed by 2679
Abstract
Although olives leaves are currently considered a waste material from oil mills, they have great potential to be transformed into by-products due to their high oleuropein content. Oleuropein is a glycoside precursor of hydroxytyrosol, which is the phenolic compound with the highest antioxidant [...] Read more.
Although olives leaves are currently considered a waste material from oil mills, they have great potential to be transformed into by-products due to their high oleuropein content. Oleuropein is a glycoside precursor of hydroxytyrosol, which is the phenolic compound with the highest antioxidant capacity in nature and which is associated with multiple health benefits. For this reason, the demand for oleuropein is growing in the pharmaceutical, cosmetic and food sectors. The objective of this study is to determine the stability of oleuropein in olive leaves from oil mills in solid and aqueous forms under different conditions of temperature, relative humidity and lighting. The results indicate that the degradation of oleuropein conforms well to first-order kinetics. The rate constants at the temperatures tested in the aqueous extracts indicate activation energies from RTl to 80 °C and from 7 °C to 14 °C, as the degradation reactions were different in these ranges. Furthermore, olive leaf powder stored at any temperature with an RH ≥ 57% showed greater stability after six months, which is an encouraging result for the storage and transformation of this waste in oil mills. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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18 pages, 30086 KiB  
Article
An In Vitro and In Silico Study of the Enhanced Antiproliferative and Pro-Oxidant Potential of Olea europaea L. cv. Arbosana Leaf Extract via Elastic Nanovesicles (Spanlastics)
by Taghreed S. Alnusaire, Ahmed M. Sayed, Abeer H. Elmaidomy, Mohammad M. Al-Sanea, Sarah Albogami, Mha Albqmi, Bassam F. Alowaiesh, Ehab M. Mostafa, Arafa Musa, Khayrya A. Youssif, Hesham Refaat, Eman M. Othman, Thomas Dandekar, Eman Alaaeldin, Mohammed M. Ghoneim and Usama Ramadan Abdelmohsen
Antioxidants 2021, 10(12), 1860; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121860 - 23 Nov 2021
Cited by 8 | Viewed by 1819
Abstract
The olive tree is a venerable Mediterranean plant and often used in traditional medicine. The main aim of the present study was to evaluate the effect of Olea europaea L. cv. Arbosana leaf extract (OLE) and its encapsulation within a spanlastic dosage form [...] Read more.
The olive tree is a venerable Mediterranean plant and often used in traditional medicine. The main aim of the present study was to evaluate the effect of Olea europaea L. cv. Arbosana leaf extract (OLE) and its encapsulation within a spanlastic dosage form on the improvement of its pro-oxidant and antiproliferative activity against HepG-2, MCF-7, and Caco-2 human cancer cell lines. The LC-HRESIMS-assisted metabolomic profile of OLE putatively annotated 20 major metabolites and showed considerable in vitro antiproliferative activity against HepG-2, MCF-7, and Caco-2 cell lines with IC50 values of 9.2 ± 0.8, 7.1 ± 0.9, and 6.5 ± 0.7 µg/mL, respectively. The encapsulation of OLE within a (spanlastic) nanocarrier system, using a spraying method and Span 40 and Tween 80 (4:1 molar ratio), was successfully carried out (size 41 ± 2.4 nm, zeta potential 13.6 ± 2.5, and EE 61.43 ± 2.03%). OLE showed enhanced thermal stability, and an improved in vitro antiproliferative effect against HepG-2, MCF-7, and Caco-2 (IC50 3.6 ± 0.2, 2.3 ± 0.1, and 1.8 ± 0.1 µg/mL, respectively) in comparison to the unprocessed extract. Both preparations were found to exhibit pro-oxidant potential inside the cancer cells, through the potential inhibitory activity of OLE against glutathione reductase and superoxide dismutase (IC50 1.18 ± 0.12 and 2.33 ± 0.19 µg/mL, respectively). These inhibitory activities were proposed via a comprehensive in silico study to be linked to the presence of certain compounds in OLE. Consequently, we assume that formulating such a herbal extract within a suitable nanocarrier would be a promising improvement of its therapeutic potential. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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12 pages, 1530 KiB  
Article
Effect of the Olive Oil Extraction Process on the Formation of Complex Pectin–Polyphenols and Their Antioxidant and Antiproliferative Activities
by Alejandra Bermúdez-Oria, Elisa Rodríguez-Juan, Guillermo Rodríguez-Gutiérrez, África Fernández-Prior and Juan Fernández-Bolaños
Antioxidants 2021, 10(12), 1858; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121858 - 23 Nov 2021
Cited by 9 | Viewed by 1701
Abstract
The aim of this research was to investigate the interaction of phenols and pectic polysaccharides during the olive oil extraction process. For this, pectin was extracted from fresh olive fruits and compared to the pectin isolated from the paste resulting from the extraction [...] Read more.
The aim of this research was to investigate the interaction of phenols and pectic polysaccharides during the olive oil extraction process. For this, pectin was extracted from fresh olive fruits and compared to the pectin isolated from the paste resulting from the extraction of the olive oil after milling with malaxation at 30 °C/30 min and subsequent centrifugation of the olive paste from the same lot of olive fruits in a system called ABENCOR (AB). The results indicate that these interactions were enhanced during the olive oil extraction process. In addition, the resulting AB extracts exhibited high antioxidant activity (ORAC) and strong antiproliferative activity in vitro against colon carcinoma Caco-2 cell lines compared to olive fruit extracts. The polyphenols associated mainly with the acidic pectin substance, with a higher content in AB extracts, seem to be responsible for these activities, and appear to maintain their activities in part after complexation. However, even in olive fruit extracts with smaller amounts of phenols in their compositions, pectic polysaccharides may also be involved in antioxidant and antiproliferative activities. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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15 pages, 707 KiB  
Article
Antioxidant Capacity of Free Volatile Compounds from Olea europaea L. cv. Oblica Leaves Depending on the Vegetation Stage
by Renata Jurišić Grubešić, Marija Nazlić, Tina Miletić, Elma Vuko, Nenad Vuletić, Ivica Ljubenkov and Valerija Dunkić
Antioxidants 2021, 10(11), 1832; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10111832 - 18 Nov 2021
Cited by 6 | Viewed by 1973
Abstract
Previous research on specialized metabolites of olive leaves has focused on the phenolic components and their biological role. The research in this article focuses on the metabolites that form free volatile compounds (FVCs). The composition of FVCs is divided into compounds isolated in [...] Read more.
Previous research on specialized metabolites of olive leaves has focused on the phenolic components and their biological role. The research in this article focuses on the metabolites that form free volatile compounds (FVCs). The composition of FVCs is divided into compounds isolated in the oil phase (essential oils; EO) and in the aqueous phase (hydrosols; Hy) from leaves of Olea europaea L. cultivar Oblica. Plant material was collected from the same olive tree over a six-month period, from December to May, and analyzed by gas chromatography–mass spectrometry (GC–MS). The compounds β-caryophyllene, α-humulene, allo-aromadendrene, docosane, hexadecanoic acid and oleic acid were identified in all EO study periods. In the Hy in all studied periods, the major compounds are α-pinene, β-ionone, myristicin, docosane, 1-hexanol, oleic acid and (E)-β-damascenone. The differences in the qualitative composition of FVC are directly related to the phenological development of the leaves. Antioxidant capacity of the EOs and hydrosols was measured with two methods, ORAC and DPPH. Hydrosol extracts showed higher capacity than the EOs in all methods. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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17 pages, 877 KiB  
Article
Optimizing the Malaxation Conditions to Produce an Arbequina EVOO with High Content of Bioactive Compounds
by Alexandra Olmo-Cunillera, Julián Lozano-Castellón, Maria Pérez, Eleftherios Miliarakis, Anna Tresserra-Rimbau, Antònia Ninot, Agustí Romero-Aroca, Rosa Maria Lamuela-Raventós and Anna Vallverdú-Queralt
Antioxidants 2021, 10(11), 1819; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10111819 - 17 Nov 2021
Cited by 12 | Viewed by 1981
Abstract
To meet the growing demand for high-quality extra-virgin olive oil (EVOO) with health-promoting properties and pleasant sensory properties, studies are needed to establish optimal production parameters. Bioactive components of EVOO, including phenolic compounds, carotenoids, chlorophylls, tocopherols, and squalene, contribute to its organoleptic properties [...] Read more.
To meet the growing demand for high-quality extra-virgin olive oil (EVOO) with health-promoting properties and pleasant sensory properties, studies are needed to establish optimal production parameters. Bioactive components of EVOO, including phenolic compounds, carotenoids, chlorophylls, tocopherols, and squalene, contribute to its organoleptic properties and beneficial health effects. The aim of this study was to develop an Arbequina EVOO with high phenol content, particularly oleocanthal and oleacein, on a laboratory scale by analyzing the effects of different temperatures (20, 25, and 30 °C) and times (30 and 45 min) of malaxation. Higher temperatures decreased the levels of the phenolic compounds, secoiridoids, tocopherols, and squalene, but increased the pigments. EVOO with the highest quality was produced using malaxation parameters of 20 °C and 30 min, although oleocanthal and oleacein were higher at 30 and 25 °C, respectively. Overall, 20 °C and 30 min were the processing conditions that most favored the physiological and chemical processes that contribute to higher levels of bioactive compounds in the oil and diminished their degradation and oxidation processes. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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13 pages, 2025 KiB  
Article
Nephroprotective Effect of the Virgin Olive Oil Polyphenol Hydroxytyrosol in Type 1-like Experimental Diabetes Mellitus: Relationships with Its Antioxidant Effect
by María Dolores Rodríguez-Pérez, Juan Antonio López-Villodres, María Monsalud Arrebola, Esther Martín-Aurioles, África Fernández-Prior, Alejandra Bermúdez-Oria, María Carmen Ríos, José Pedro De La Cruz and José Antonio González-Correa
Antioxidants 2021, 10(11), 1783; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10111783 - 08 Nov 2021
Cited by 7 | Viewed by 2099
Abstract
The aim of this study was to determine whether hydroxytyrosol administration prevented kidney damage in an experimental model of type 1 diabetes mellitus in rats. Hydroxytyrosol was administered to streptozotocin-diabetic rats: 1 and 5 mg/kg/day p.o. for two months. After hydroxytyrosol administration, proteinuria [...] Read more.
The aim of this study was to determine whether hydroxytyrosol administration prevented kidney damage in an experimental model of type 1 diabetes mellitus in rats. Hydroxytyrosol was administered to streptozotocin-diabetic rats: 1 and 5 mg/kg/day p.o. for two months. After hydroxytyrosol administration, proteinuria was significantly reduced (67–73%), calculated creatinine clearance was significantly increased (26–38%), and the glomerular volume and glomerulosclerosis index were decreased (20–30%). Hydroxytyrosol reduced oxidative and nitrosative stress variables and thromboxane metabolite production. Statistical correlations were found between biochemical and kidney function variables. Oral administration of 1 and 5 mg/kg/day of hydroxytyrosol produced an antioxidant and nephroprotective effect in an experimental model of type 1-like diabetes mellitus. The nephroprotective effect was significantly associated with the systemic and renal antioxidant action of hydroxytyrosol, which also influenced eicosanoid production. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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19 pages, 2893 KiB  
Article
Sequential Extraction of Hydroxytyrosol, Mannitol and Triterpenic Acids Using a Green Optimized Procedure Based on Ultrasound
by Irene Gómez-Cruz, María del Mar Contreras, Inmaculada Romero and Eulogio Castro
Antioxidants 2021, 10(11), 1781; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10111781 - 07 Nov 2021
Cited by 9 | Viewed by 2732
Abstract
Olive-derived biomasses contain bioactive compounds with health promoting effects as well as antioxidant and sweet-tasting properties. However, their sequential extraction has not been attained. In the present study, firstly antioxidants and mannitol were extracted from exhausted olive pomace (EOP) by an eco-friendly method, [...] Read more.
Olive-derived biomasses contain bioactive compounds with health promoting effects as well as antioxidant and sweet-tasting properties. However, their sequential extraction has not been attained. In the present study, firstly antioxidants and mannitol were extracted from exhausted olive pomace (EOP) by an eco-friendly method, ultrasound-assisted water extraction (UAWE). The amplitude (20–80%), extraction time (2–18 min) and solid loading (2–15%, w/v) were evaluated according to a Box–Behnken experimental design. Using the response surface methodology, the optimal conditions for extraction were obtained: 80% amplitude, 11.5% solid loading and 16 min. It enabled the multi-response optimization of the total phenolic content (TPC) (40.04 mg/g EOP), hydroxytyrosol content (6.42 mg/g EOP), mannitol content (50.92 mg/g EOP) and antioxidant activity (ferric reducing power or FRAP, 50.95 mg/g EOP; ABTS, 100.64 mg/g EOP). Moreover, the phenolic profile of the extracts was determined by liquid chromatography-UV and mass spectrometry, identifying hydroxytyrosol as the main phenolic compound and other minor derivatives could be characterized. Scanning electron microscopy was used to analyze the morphological changes produced in the cellular structure of EOP after UAWE. In addition, the chemical composition of the extracted EOP solid was characterized for further valorization. Then, a second extraction step was performed in order to extract bioactive triterpenes from the latter solid. The triterpenes content in the extract was determined and the effect of the previous UAWE step on the triterpenes extraction was evaluated. In this case, the use of ultrasound enhanced the extraction of maslinic acid and oleanolic acid from pelletized EOP with no milling requirement. Overall, UAWE can be applied to obtain antioxidant compounds and mannitol as first extraction step from pelletized EOP while supporting the subsequent recovery of triterpenic acids. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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11 pages, 1148 KiB  
Article
An Easy-to-Use Procedure for the Measurement of Total Phenolic Compounds in Olive Fruit
by Pilar Luaces, Mar Pascual, Ana G. Pérez and Carlos Sanz
Antioxidants 2021, 10(11), 1656; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10111656 - 21 Oct 2021
Cited by 7 | Viewed by 2039
Abstract
Virgin olive oil (VOO) is one of the most emblematic products of the Mediterranean diet. Its content in phenolic compounds is strongly associated with the antioxidant and health-promoting properties of this diet. VOO’s phenolic profile is determined mainly by the phenolic compounds present [...] Read more.
Virgin olive oil (VOO) is one of the most emblematic products of the Mediterranean diet. Its content in phenolic compounds is strongly associated with the antioxidant and health-promoting properties of this diet. VOO’s phenolic profile is determined mainly by the phenolic compounds present in the olive fruit, so knowing their content allows for a fairly precise estimate of the antioxidant and functional properties of the corresponding oil. In this sense, a convenient, green, and sensitive spectrophotometric method was developed for the quantitative determination of total phenolic compounds in olive fruits. The method is based on an easy-to-use extraction procedure of olive fruit phenolics using dimethyl sulfoxide and quantification with the Folin–Ciocalteu reagent. Oleuropein proved to be a suitable reference compound for quantification, displaying a good linear response (r = 0.9996) over the concentration range of 0.58–6.48 mg/mL, with a variation coefficient of 0.42% and limits of detection and quantification of 0.0492 and 0.1490 mg/mL, respectively. The method was validated using a wide array of fruit samples representative of the Olea europaea L. genetic diversity. The results obtained with this spectrophotometric method, expressed as mg/mL of oleuropein, showed a good correlation with those obtained with the fruit samples analyzed by high performance liquid chromatography, with an r value of 0.9930 and a slope value of 1.022, confirming its reliability. Thus, this method can become a very useful simple tool to estimate the total phenolic content of olive fruits, especially when working with numerous samples such as in olive breeding programs or in commercial olive production, in which it is especially useful to know the phenolic state of the fruit and thus determine the optimal harvest date or the most appropriate agronomic treatment to increase the functional properties of the olive fruit and the olive oil. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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15 pages, 1262 KiB  
Article
Exploiting Food-Grade Mesoporous Silica to Preserve the Antioxidant Properties of Fresh Olive Mill Wastewaters Phenolic Extracts
by Federica Ianni, Andrea Gagliardi, Agnese Taticchi, Maurizio Servili, Nicola Pinna, Aurélie Schoubben, Roccaldo Sardella and Stefano Bruscoli
Antioxidants 2021, 10(9), 1361; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10091361 - 26 Aug 2021
Cited by 6 | Viewed by 1695
Abstract
Fresh olive mill wastewaters phenolic extracts are of great interest as preservatives or fortifying ingredients but are characterized by limited stability. The purpose of this study was to use mesoporous silica to enhance their stability and preserve their antioxidant properties. The phenolic extracts [...] Read more.
Fresh olive mill wastewaters phenolic extracts are of great interest as preservatives or fortifying ingredients but are characterized by limited stability. The purpose of this study was to use mesoporous silica to enhance their stability and preserve their antioxidant properties. The phenolic extracts were characterized for their composition by HPLC-DAD and included in a mesoporous matrix with or without a lipid coating. The inclusion complexes were characterized in terms of total phenolic content, radical scavenging capacity and in vitro antioxidative activity and cell compatibility. Besides, inclusion complex stability under different storage conditions (22 and 37 °C, 75% relative humidity, 1 month) was evaluated. The inclusion process was nearly quantitative and modified neither the total phenolic content nor the total antioxidant capacity. None of the inclusion complex concentrations assayed on the HT29 cell line showed toxicity. Moreover, HT29 cells treated with the inclusion complex exhibited a significant antioxidant effect, while the lipid coating impaired the antioxidant activity. The complexes without lipid were stable under all the investigated conditions, while the lipid-coated products were less stable under the more drastic conditions. Overall, inclusion complexes in mesoporous silica have suitable characteristics to be used for different applications, including food supplementation. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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13 pages, 1332 KiB  
Article
Inhibitory Effect of Olive Phenolic Compounds Isolated from Olive Oil By-Product on Melanosis of Shrimps
by Antonio Lama-Muñoz, Antonio Gómez-Carretero, Fátima Rubio-Senent, Alejandra Bermúdez-Oria, Inés Maya, José G. Fernández-Bolaños, Blanca Vioque and Juan Fernández-Bolaños
Antioxidants 2021, 10(5), 728; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10050728 - 05 May 2021
Cited by 3 | Viewed by 2127
Abstract
Melanosis is an unsolved problem of the crustacean industry and the cause of great loss of value. This study investigates the effect of two potent, natural antioxidants isolated from olive waste (hydroxytyrosol, HT and 3,4-dihydroxyphenylglycol, DHPG) and three novel HT-derivatives containing selenium and [...] Read more.
Melanosis is an unsolved problem of the crustacean industry and the cause of great loss of value. This study investigates the effect of two potent, natural antioxidants isolated from olive waste (hydroxytyrosol, HT and 3,4-dihydroxyphenylglycol, DHPG) and three novel HT-derivatives containing selenium and sulfur (dihydroxytyrosyl diselenide, N-hydroxytyrosyl selenourea, and N-hydroxytyrosyl thiourea) on the prevention of melanosis in Atlantic ditch shrimp (Palaemonetes varians) during refrigerated storage. These results clearly demonstrate the positive inhibitory effect of DHPG and dihydroxytyrosyl diselenide on delaying melanosis in vivo, although this effect was not dose dependent. The effect was associated with a concomitant-inhibitory effect on tyrosinase activity in vitro. To our knowledge, so far no studies on the prevention of melanosis have been conducted on this small specie of shrimp which is available in large quantities at any time of the year at low cost. Studies with these promising compounds could then be extended to other more economically important species with a greater guarantee of success. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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17 pages, 13909 KiB  
Article
Antiulcer Potential of Olea europea L. cv. Arbequina Leaf Extract Supported by Metabolic Profiling and Molecular Docking
by Arafa Musa, Nourhan Hisham Shady, Shaimaa R. Ahmed, Taghreed S. Alnusaire, Ahmed M. Sayed, Bassam F. Alowaiesh, Ibrahim Sabouni, Mohammad M. Al-Sanea, Ehab M. Mostafa, Khayrya A. Youssif, Dalia H. Abu-Baih, Mahmoud A. Elrehany and Usama Ramadan Abdelmohsen
Antioxidants 2021, 10(5), 644; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10050644 - 22 Apr 2021
Cited by 18 | Viewed by 3260
Abstract
Gastric ulceration is among the most serious humanpublic health problems. Olea europea L. cv. Arbequina is one of the numerous olive varieties which have scarcely been studied. The reported antioxidant and anti-inflammatory potential of the olive plant make it a potential prophylactic natural [...] Read more.
Gastric ulceration is among the most serious humanpublic health problems. Olea europea L. cv. Arbequina is one of the numerous olive varieties which have scarcely been studied. The reported antioxidant and anti-inflammatory potential of the olive plant make it a potential prophylactic natural product against gastric ulcers. Consequently, the main goal of this study is to investigate the gastroprotective effect of Olea europea L. cv. Arbequina leaf extract. LC-HRMS-based metabolic profiling of the alcoholic extract of Olea europea L. cv. Arbequina led to the dereplication of 18 putative compounds (1–18). In vivo indomethacin-induced gastric ulcer in a rat model was established and the Olea europea extract was tested at a dose of 300 mg kg−1 compared to cimetidine (100 mg kg−1). The assessment of gastric mucosal lesions and histopathology of gastric tissue was done. It has been proved that Olea europea significantly decreased the ulcer index and protected the mucosa from lesions. The antioxidant potential of the extract was evaluated using three in vitro assays, H2O2 scavenging, xanthine oxidase inhibitory, and superoxide radical scavenging activities and showed promising activities. Moreover, an in silico based study was performed on the putatively dereplicated compounds, which highlighted that 3-hydroxy tyrosol (4) and oleacein (18) can target the 5-lipoxygenase enzyme (5-LOX) as a protective mechanism against the pathogenesis of ulceration. Upon experimental validation, both compounds 3-hydroxy tyrosol (HT) and oleacein (OC) (4 and 18, respectively) exhibited a significant in vitro 5-LOX inhibitory activity with IC50 values of 8.6 and 5.8 µg/mL, respectively. The present study suggested a possible implication of O. europea leaves as a potential candidate having gastroprotective, antioxidant, and 5-LOX inhibitory activity for the management of gastric ulcers. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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11 pages, 1918 KiB  
Article
Looking for Minor Phenolic Compounds in Extra Virgin Olive Oils Using Neutron and Raman Spectroscopies
by Roberto Senesi, Carla Andreani, Piero Baglioni, Luis A. E. Batista de Carvalho, Silvia Licoccia, Maria P. M. Marques, Giulia Moretti, Annalisa Noce, Roberto Paolesse, Stewart F. Parker, Enrico Preziosi, Giovanni Romanelli, Annalisa Romani and Nicola Di Daniele
Antioxidants 2021, 10(5), 643; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10050643 - 22 Apr 2021
Cited by 5 | Viewed by 2275
Abstract
Extra virgin olive oil (EVOO) is defined as a functional food as it contains numerous phenolic components with well-recognized health-beneficial properties, such as high antioxidant and anti-inflammatory capacity. These characteristics depend on their structural/conformational behavior, which is largely determined by intra- and intermolecular [...] Read more.
Extra virgin olive oil (EVOO) is defined as a functional food as it contains numerous phenolic components with well-recognized health-beneficial properties, such as high antioxidant and anti-inflammatory capacity. These characteristics depend on their structural/conformational behavior, which is largely determined by intra- and intermolecular H-bond interactions. While the vibrational dynamics of isolated compounds have been studied in a number of recent investigations, their signal in a real-life sample of EVOO is overwhelmed by the major constituent acids. Here, we provide a full characterization of the vibrational spectroscopic signal from commercially available EVOO samples using Inelastic Neutron Scattering (INS) and Raman spectroscopies. The spectra are dominated by CH2 vibrations, especially at about 750 cm−1 and 1300 cm−1. By comparison with the spectra from hydroxytyrosol and other minor phenolic compounds, we show that the best regions in which to look for the structure–activity information related to the minor polar compounds is at 675 and 1200 cm−1 for hydroxytyrosol, and around 450 cm−1 for all minor polar compounds used as reference, especially if a selectively deuterated sample is available. The regional origin of the EVOO samples investigated appears to be related to the different amount of phenolic esters versus acids as reflected by the relative intensities of the peaks at 1655 and 1747 cm−1. Full article
(This article belongs to the Special Issue Olive Antioxidants: Extraction, Biological Activity and Practical Applications)
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