Olive Extract Research Articles

Enhancing physical and chemical stability of hygroscopic hydroxytyrosol by cocrystal formation

Hydroxytyrosol (HT) is a natural phenolic compound with potent antioxidant activity extracted from olive trees. It is generally a slightly hydrated viscous liquid at ambient conditions, and it is highly susceptible to oxygen due to the presence of catechol moiety. Although encapsulation technique provides HT in powder form, it does not improve its chemical stability. Herein, we propose an efficient solution to the high hygroscopicity and poor stability of HT. Four cocrystals were first reported, and their intermolecular interactions were analyzed in detail. After cocrystallization, the melting point is increased and the hygroscopicity is significantly decreased. HT cocrystals are thus solid at room temperature. Moreover, hydroxytyrosol cocrystals with betaine (HT-BET) and nicotinamide (HT-NIC) demonstrate superior chemical stability than pure HT, olive extract, and HT encapsulation material. Therefore, cocrystallization can be considered as a promising approach to overcome the application obstacles of HT.

Novel biosynthesis of gold nanoparticles for multifunctional applications: Electrochemical detection of hydrazine and treatment of gastric cancer

In this work, an environmentally friendly strategy was used to synthesize gold nanoparticles (Au NPs) using Olea europaea (olive) fruit. Transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) were used to characterize the physicochemical properties of the synthesized NPs. An Au NPs modified glassy carbon electrode was used to investigate the direct electrochemical oxidation of hydrazine. The suggested hydrazine sensor has good performance, such as a wide linear range (2.5–275 μM), low limit of detection (0.09 μM), notable selectivity and excellent reproducibility (RSD = 2.2%). The in-vitro cytotoxicity of three human cancer cell lines (KATOIII, NCI-N87, and SNU-16) was also explored with various concentrations of Au NPs prepared from olive fruit extract. Bio-synthesized Au NPs were found to have cytotoxic properties against gastric cancer in humans based on MTT assay protocol. The obtained results show that green synthesized Au NPs can be successfully employed in electrochemical sensing and cancer treatment applications.

Phytoconstituent Profiles Associated with Relevant Antioxidant Potential and Variable Nutritive Effects of the Olive, Sweet Almond, and Black Mulberry Gemmotherapy Extracts.

The extracts of whole plants or specific organs from different plant species are gaining increasing attention for their phytotherapy applications. Accordingly, we prepared standardized gemmotherapy extracts (GTEs) from young shoots/buds of olive (Olea europaea), sweet almond (Prunus amygdalus), and black mulberry (Morus nigra), and analyzed the corresponding phytonutrient profiles. We identified 42, 103, and 109 phytonutrients in the olive, almond, and black mulberry GTEs, respectively, containing amino acids, vitamins, polyphenols, flavonoids, coumarins, alkaloids, iridoids, carboxylic acids, lignans, terpenoids, and others. In order to assess the physiological effects generated by the GTEs, we developed a translational nutrition model based on Drosophila melanogaster and Cyprinus carpio. The results indicate that GTEs could influence, to a variable extent, viability and ATP synthesis, even though both are dependent on the specific carbohydrate load of the applied diet and the amino acid and polyphenol pools provided by the GTEs. It seems, therefore, likely that the complex chemical composition of the GTEs offers nutritional properties that cannot be separated from the health-promoting mechanisms that ultimately increase viability and survival. Such an approach sets the paves the way for the nutritional genomic descriptions regarding GTE-associated health-promoting effects.

Olive Mill Wastewater as Source of Polyphenols with Nutraceutical Properties.

Agrifood waste products are often considered rich sources of bioactive compounds that can be conveniently recovered. Due to these peculiar characteristics, the study of these waste products is attracting great interest in nutraceutical research. Olive mill wastewaters (OMWWs) are generated by extra virgin olive oil (EVOO) production, and they pose environmental challenges due to their disposal. This study aimed to characterize the polyphenolic profile and to evaluate the nutraceutical properties of OMWW extracts from two Tuscan olive cultivars, Leccino (CL) and Frantoio (CF), collected during different time points in EVOO production. After a liquid-liquid extraction, the HPLC and LC-MS/MS analysis of OMWW extracts confirmed the presence of 18 polyphenolic compounds. The polyphenol composition varied between the cultivars and during maturation stages. Notably, oleacein was detected at remarkably high levels in CL1 and CF1 extracts (314.628 ± 19.535 and 227.273 ± 3.974 μg/mg, respectively). All samples demonstrated scavenging effects on free radicals (DPPH and ABTS assays) and an anti-inflammatory potential by inhibiting cyclooxygenase (COX) enzymes. This study highlights the nutraceutical potential of OMWW extracts, emphasizing their antioxidant, antiradical, and anti-inflammatory activities. The results demonstrate the influence of olive cultivar, maturation stage, and extraction process on the polyphenolic composition and the bioactivity of OMWW extracts. These findings support a more profitable reuse of OMWW as an innovative, renewable, and low-cost source of dietary polyphenols with potential applications as functional ingredients in the development of dietary supplements, as well as in the pharmaceutical and cosmetics industries.

Modeling the antimicrobial effects of olive mill waste extract, rich in hydroxytyrosol, on the growth of lactic acid bacteria using response surface methodology.

The objective of this study is to assess the inhibitory effects of an aqueous extract from olive oil mill waste (alperujo) on the growth of a lactic acid bacteria (LAB) cocktail consisting of various strains of Lactiplantibacillus pentosus and Lactiplantibacillus plantarum species. For this purpose, response surface methodology was employed using two independent variables (pH levels 3.5-5.55; hydroxytyrosol concentration ranging from 0.93-2990ppm). The response variable was the average inhibition per treatment on the LAB cocktail (expressed as a percentage). The developed model identified significant terms, including the linear effect of hydroxytyrosol and pH, their interaction, and the quadratic effect of pH. Maximum inhibition of the LAB cocktail was observed at progressively higher concentrations of hydroxytyrosol and lower pH values. Therefore, complete inhibition of LAB in the synthetic culture medium could only be achieved for concentrations of 2984ppm hydroxytyrosol at a pH of 3.95. These findings suggest that extracts derived from "alperujo" could be utilized as a natural preservative in acidified foods with a bitter flavor and antioxidant requirements.

Allergy to cypress and olive pollen: Clinical phenotypes and allergen recognition.

Cypress and olive pollen are the most prevalent sensitizer trees in the Mediterranean area. Some patients exhibit a dual sensitization which has not been well documented yet. To identify the allergens involved in the dual cypress and olive allergy (C+O) and study the relationship between phenotype and allergen sensitization. C+O patients were selected. Monosensitized subjects to olive or cypress were used as reference. Specific IgE to whole extracts and purified allergens from olive and cypress were performed. Immunoblotting was done to analyze IgG and IgE-binding using olive polyclonal antibodies and patients' sera, respectively. Mutual immunoblotting inhibition of olive and cypress extracts, and inhibition of cypress extract immunoblotting with olive allergens were performed. Multiple correspondence analysis and hierarchical cluster classifications were conducted to analyze the relationships between C+O clinical presentation (symptoms, seasonality) and allergen profile. C+O patients were clustered in 4 phenotypes. The most frequent one (58.4%) was rhinoconjunctivitis in winter (February) and spring (May), with asthma in 38% of subjects. Ole e 1 and Cup s 1 were the major allergens. Homologous proteins to Ole e 1, Ole e 9 and Ole e 11 in cypress pollen were identified and these olive allergens inhibit IgE-binding to cypress extract. The exclusive C+O allergy results from co-sensitization to Cup s 1 and Ole e 1, and to cross-reactivity due to Ole e 1-like, Ole e 9-like and Ole e 11-like allergens not described previously, and translates into 4 clinical phenotypes of winter and/or spring or perennial rhinoconjunctivitis with and without asthma.

Solvent-resistant ultrafiltration to recover bioactive compounds from wet olive pomace extracts

To contribute to the circular economy in olive mills, wet olive pomace can be employed as a source of valuable phenolic compounds. These compounds are efficiently extracted with ethanol/water 50:50 (v/v), at 40 °C. Here, the ultrafiltration membranes UF010104, UF010801v3 (from SolSep BV), and UP005 (Microdyn Nadir) have been tested to purify the phenolic compounds present in the hydroalcoholic extracts of the pomace. Several membrane conditioning protocols were explored, being the most adequate a short pre-treatment consisting of soaking the membrane in the working solvent for 2 h. All the considered membranes permitted the recovery of the biophenols of interest in the permeate stream, being most of the organic matter retained. A powerful analytical methodology based on liquid chromatography coupled to mass spectrometry (LC-ESI-QToF-MS) allowed the evaluation of the individual rejection of 43 compounds. The UF010104 membrane displayed the highest permeate flux (15 L h−1·m−2, at 2.5 bar) and high rejection of the total solids (67 ± 3%, at 2.5 bar), thus achieving the purification of the phenolic compounds in the permeate stream. The cleaning of the membranes used in organic solvent media was also investigated.

Effects of maslinic acid supplementation on exercise-induced inflammation and oxidative stress in water polo athletes: A randomized, double-blind, crossover, and placebo-controlled trial.

Olive fruit is rich in bioactive pentacyclic triterpenoids, primarily maslinic acid (MA). Previous studies have demonstrated that MA exhibits anti-inflammatory and anti-oxidative effects; however, it is unclear whether MA intake during training inhibits perceptual fatigue and muscle soreness in athletes. This study analyzed the effects of MA supplementation during athletic training on perceptual fatigue and muscle soreness. This randomized, double-blind, cross-over, and placebo-controlled trial involved 12 young, healthy male water polo athletes. After daily training for seven days, they ingested either olive fruit extract, containing 60 mg/day MA, or a placebo. We measured perceptual fatigue and muscle soreness during the intervention using a visual analog scale and inflammatory and oxidative stress-related proteins. Perceptual fatigue and muscle soreness and the area under the curve during the training period were significantly lower (main effect of MA; P < 0.05) following MA supplementation than those for the placebo. MA supplementation during training lowered perceptual fatigue and muscle soreness by decreasing inflammatory factors in water polo athletes. Additionally, we examined the detailed mechanism of MA, added the participant's serum to the culture medium at a 10% concentration to determine inflammation- and oxidative stress-related intracellular signals. Skeletal muscle cells (C2C12) cultured with MA-conditioned serum before and after intervention also suppressed expression of inflammation and oxidative stress-related proteins. These findings suggest that MA intake not only reduces perceptual fatigue and muscle soreness but also decreases inflammation and oxidative stress in the blood and skeletal muscle.

Use of olive pomace extract as a pollinator attractant to increase onion (Allium cepa L.) seed crop production

Onion is an allogamous species with protandry, as anthers release pollen before the stigma is receptive. Thus, insect pollination is needed to produce seeds. When male sterile lines are used, an efficient pollinator is important to ensure pollen transfer to the stigma. Therefore, increasing seed yield depends on increasing bee activity. Seed yield is variable in hybrid lines and lower than open-pollinated varieties, with a decrease of up to 60%. Bee attractants sometimes are used to influence worker bees towards flowers for pollination. The objective of this work is to use a food industry waste, such as olive pomace, as bee attractant upon application of the water extract on onion umbels. The effectiveness of this by-product in enhancing pollination efficiency was evaluated and compared to untreated controls. Male-sterile lines, as well as a fertile line, were used in commercial fields and environmental variables were registered. Pollination effectiveness was measured by seed yield. Olive pomace water extracts (OPWE), rich in bioactive compounds, from local industries were evaluated. Some compounds present in the OPWE were analyzed, identified and quantified. The OPWEs were applied during flowering, at different times and correlated with seed yield and the frequency of bee visits. After 3 years of study, we can assert that the application of OPWE enhances honeybee pollination efficiency, and as consequence improves onion seed yield.

White rice enrichment with phenols upon cooking in olive leaf infusion: a preliminary study.

White rice is poor in health-promoting phytochemicals; therefore, the production of a phenol-enriched commodity is highly desirable. Recent findings on its enrichment via cooking in plant extracts are promising, yet studies employing aqueous extracts of olive leaves (OLs), containing well-recognized bioactive phenols (e.g. oleuropein) are absent. In addition, little is known about the levels of phenols that are maintained after rice drying and rehydration, an important aspect for the future design of 'ready-to-eat' functional rice. The examination, for the first time, of white rice adsorption capacity of phenols from OLs upon cooking in infusions containing different levels of phenols, after freeze-drying and rehydration, showed the following: (i) the total phenol content, the antioxidant activity (assessed via 2,2-diphenyl-1-picrylhydrazyl radical and ferric reducing antioxidant power assays), the oleuropein and luteolin-7-O-glucoside levels increased dose dependently; (ii) upon rehydration, the average decrease of total phenol content and antioxidant activity values was significantly lower when an exact volume of water was used compared with an excess (~10% versus 63%). A similar trend was observed for oleuropein (36% versus 83%) and the luteolin-7-O-glucoside (24 versus 82%) levels; (iii) the dried enriched kernels were less bright with a hay-yellow hue (CIELab coordinates). White rice enrichment with biophenols from OLs, a by-product of olive tree cultivation, was successful using a simple approach. Despite leaching upon freeze-drying/rehydration, sufficient amounts were maintained to obtain a functional rice that could serve as an alternative dietary source of OLs phenols to non-traditional olive tree product consumers or those refraining from sodium and fats. © 2023 Society of Chemical Industry.

Development of Gluten-Free Functional Bread Adapted to the Nutritional Requirements of Celiac Patients

Celiac patients suffer from nutritional deficiencies before and during the maintenance of a gluten-free diet; this is due to non-fortified, mostly processed foods that are high in saturated fat and deficient in minerals typically present in wheat. A literature search was carried out to determine the deficiencies of these patients in calcium, iron, fiber, folic acid, omega-3, vitamin B12 and vitamin D. Different formulations of gluten-free bread enriched with olive extract (hydroxytyrosol of natural (HXTO) and synthetic (HXTS) origin), acerola extract, citrus extract, spinach extract, calcium, iron and linseed were used. Antioxidant capacity, nutritional composition, folates, minerals, color and pH were studied, and a microbiological study and sensory analysis were conducted to assess organoleptic quality. These studies were carried out on days 0, 4, 7 and 11 to study their evolution. The results of the HXTS bread showed a higher antioxidant capacity, higher antimicrobial capacity and higher fiber content, as well as higher amounts of minerals. It also showed higher consumer acceptability, even relative to commercial gluten-free bread. The HXTO bread showed higher antimicrobial capacity than the control (C), higher fiber content and higher mineral content, but had lower antimicrobial capacity than HTXS bread. It also had better sensory acceptability than C but was worse than HXTS bread. Taking into account the physicochemical and organoleptic characteristics, the HXTS sample is the most suitable for enriching the diet of celiac patients.

Olive extract enriched with hydroxytyrosol improves cardiac and vascular function in patients with stable coronary artery disease: a double-blind, placebo-controlled trial

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Olive Heart Operational Programme Competitiveness, Entrepreneurship and Innovation 2014–2020 (EPAnEK) Aims We investigated the effect of olive extract enriched with hydroxytyrosol, on vascular and myocardial function markers in patients with stable coronary artery disease (SCAD). Methods In a prospective, cross-over, double-blind, placebo-controlled, clinical trial, 30 patients with stable CAD were randomly assigned to an oral supplement containing olive oil extract enriched with hydroxytyrosol (OOHT) or placebo for one month and then were crossed over to the alternate treatment (placebo or OOHT for one more month). We measured a) perfused boundary region (PBR) of the sublingual arterial microvessels (increased PBR indicates reduced endothelial glycocalyx thickness), b) flow-mediated dilation (FMD), c) Coronary Flow Reserve (CFR) and markers of LV diastolic function by Doppler echocardiography d) Pulse Wave Velocity (PWV) e) oxidative/nitrosative stress and inflammatory biomarkers and blood lipids at baseline and after one month treatment. Results Treatment with OOHT improved PBR, FMD, CFR and PWV compared to baseline (1.81±0.35 vs 1.77±0.40 μm p = 0.04 3.71±2.12 vs 6.51±2.31%, p&amp;lt;0.001;2.37±0.40 vs 2.45±0.41, p = 0.030 and 11.03±1.81 vs 11.78±2.34 m/sec, p = 0.002), while there was no effect after placebo (p&amp;gt;0.05). Compared to baseline, treatment with OOHT reduced malondialdehyde (MDA) a marker of lipid peroxidation (2.10±1.37 vs 1.69±0.83 mmol/lt, p = 0.045), oxidized LDL, triglycerides, PCSK9 and CRP blood levels (p&amp;lt;0.05) in contrast to placebo. There was a parallel improvement of E’ of the mitral annulus and deceleration time of the E wave of mitral inflow after OOHT (p&amp;lt;0.05) but not after placebo. Conclusions Olive extract enriched with hydroxytyrosol improves endothelial and arterial function likely by reducing oxidative and inflammatory burden leading to improved LV diastolic function after one month of treatment in patients with stable CAD.

Oxidative Stability of Avocado Snacks Formulated with Olive Extract as an Active Ingredient for Novel Food Production.

Analysis of the oxidative stability of novel avocado chips with added natural extracts was carried out with the aim of reducing the chemical additive content in their formulation. Two different natural extracts were initially evaluated and characterized: one obtained from olive pomace (OE) and other from pomegranate seed waste. OE was selected due to its better antioxidant potential according to FRAP, ABTS, and DPPH assays as well as its higher total phenolic content. The formulations used were 0, 1.5 wt.%, and 3 wt.% of OE. A gradual disappearance of the band found around 3009 cm-1 and related to unsaturated fatty acids was observed in the control sample in contrast to formulations with added OE. The band observed near 3299 cm-1 widened and intensified with time due to the oxidation degree of samples, with this effect being higher in the control chips. The observed changes in fatty acid and hexanal content with storage time underlined the higher extent of oxidation in the control samples. This fact could suggest an antioxidant protectant action of OE in avocado chips during thermal treatment, which was attributed to the presence of phenolic compounds. The obtained chips incorporating OE represent a viable option for the development of a natural, healthy, and clean-label avocado snack at competitive cost and with low environmental impacts.

Biological activities and related phenolic compounds content of olive and plum stones ethanolic extract

Biological activities and related phenolic compounds content of olive and plum stones ethanolic extract

Green Synthesis of ZnO-TiO2 Nano-Photocatalyst Doped with Fe(III) Ions Using Bitter Olive Extract to Treat Textile Wastewater Containing Reactive Dyes

Green Synthesis of ZnO-TiO2 Nano-Photocatalyst Doped with Fe(III) Ions Using Bitter Olive Extract to Treat Textile Wastewater Containing Reactive Dyes

Biosynthesis of phyto-functionalized silver nanoparticles using olive fruit extract and evaluation of their antibacterial and antioxidant properties.

The green synthesis of nanomaterials is of utmost interest as it offers an eco-friendly approach over chemical synthetic routes. However, the reported biosynthesis methods are often time-consuming and require heating or mechanical stirring. The current study reports a facile one-pot biosynthesis of silver nanoparticles (AgNPs) mediated by olive fruit extract (OFE) and sunlight irradiation of only 20s. OFE acts as both a reducing and a capping agent for the formation of OFE-capped AgNPs (AgNPs@OFE). The as-synthesized NPs were systematically characterized by UV-vis spectrometry, Fourier transform infrared (FTIR) spectroscopy, scanning electrochemical microscopy with energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), dynamic light scattering (DLS), and cyclic voltammetry. SEM images confirmed the successful formation of monodispersed spherical AgNPs@OFE of approximately 77nm. FTIR spectroscopy suggested the involvement of functional groups of phytochemicals from the OFE in the capping and reduction of Ag+ to Ag. The particles revealed excellent colloidal stability as evidenced from the high zeta potential (ZP) value (-40mV). Interestingly, using the disk diffusion method, AgNPs@OFE revealed higher inhibition efficiency against Gram-negative bacteria (Escherichia coli, Klebsiella oxytoca, and extensively drug-resistant (XDR) Salmonella typhi) than Gram-positive bacteria (Staphylococcus aureus), with Escherichia coli showing the highest inhibition zone of 27mm. In addition, AgNPs@OFE exhibited maximum potent antioxidant scavenging potential against H2O2, followed by DPPH, O2 -, and OH- free radicals. Overall, OFE can be considered an effective source for the sustainable production of stable AgNPs with potential antioxidant and antibacterial activities for biomedical applications.

A Systematic Ex-Vivo Study of the Anti-Proliferative/Cytotoxic Bioactivity of Major Olive Secoiridoids' Double Combinations and of Total Olive Oil Phenolic Extracts on Multiple Cell-Culture Based Cancer Models Highlights Synergistic Effects.

Several individual olive oil phenols (OOPs) and their secoiridoid derivatives have been shown to exert anti-proliferative and pro-apoptotic activity in treatments of human cancer cell lines originating from several tissues. This study evaluated the synergistic anti-proliferative/cytotoxic effects of five olive secoiridoid derivatives (oleocanthal, oleacein, oleuropein aglycone, ligstroside aglycone and oleomissional) in all possible double combinations and of total phenolic extracts (TPEs) on eleven human cancer cell lines representing eight cell-culture-based cancer models. Individual OOPs were used to treat cells for 72 h in half of their EC50 values for each cell line and their synergistic, additive or antagonistic interactions were evaluated by calculating the coefficient for drug interactions (CDI) for each double combination of OOPs. Olive oil TPEs of determined OOPs' content, originating from three different harvests of autochthonous olive cultivars in Greece, were evaluated as an attempt to investigate the efficacy of OOPs to reduce cancer cell numbers as part of olive oil consumption. Most combinations of OOPs showed strong synergistic effect (CDIs < 0.9) in their efficacy, whereas TPEs strongly impaired cancer cell viability, better than most individual OOPs tested herein, including the most resistant cancer cell lines evaluated.

Biosynthesis of Zinc Oxide Nanoparticles using Fermented Table Olive Extract: A Novel and Green Approach with Potential Applications

Biosynthesis of Zinc Oxide Nanoparticles using Fermented Table Olive Extract: A Novel and Green Approach with Potential Applications

L’olivier, une richesse méditerranéenne au prix d’une allergie complexe

The olive tree (Olea europea L.) is a characteristic tree of Mediterranean basin countries, responsible for the most frequent pollinosis. This pollinosis is influenced by climate change, which can anticipate flowering dates, increase the quantity of pollen produced, and the pollen season length. The occurrence of olive pollinosis mainly depends on HLA class II, IL-13 and IL-4RA genes; and environment factors, such as socioeconomic and nutritional status, physical activity and exposure to different stimuli. Among deferent categories of molecular allergens involved in olive pollinosis, Ole e 1 is the main allergen, and the presence of homology between these allergens, and those of other species from the Oleaceae family and other different taxons (Poaceae), is responsible for cross-reactions. Polysensitization is a major challenge in the diagnostic and therapeutic approach and highlights the importance of using molecular allergens in the pollinosis diagnostic. Furthermore, allergy to the olive tree has nowadays benefited from progress in specific immunotherapy, thanks in particular to the development of a strategy based on allergenic peptides as an alternative to whole olive tree pollen extracts.

Plasma fatty acid profile in Italian Holstein-Friesian dairy cows supplemented with natural polyphenols from the olive plant Olea Europaea L.

This study evaluated the effects of supplementing with natural functional feed on the plasma fatty acid profile of lactating Italian Holstein-Friesian dairy cows. Thirty cows in mid-lactation received the natural olive extract PHENOFEED DRY (500 mg/cow/day) which mainly comprises hydroxytyrosol, tyrosol and verbascoside. The total content of polyphenols and the antioxidant power of standard feed, enriched feed and pure extract was evaluated respectively by Folin-Ciocalteu and DPPH assay, and a characterization in HPLC-UV (High-Performance Liquid Chromatography-Ultraviolet) of bioactive molecules present in the extract PHENOFEED DRY was performed. PHENOFEED DRY was provided for 60 days, and the plasma profile of fatty acids was determined by Gas Chromatography. The administration of enriched feed resulted in an increase in the ratio of Omega-6 to Omega-3 polyunsaturated fatty acids from 3:1 to 4:1 (p<0.001). This was not influenced by the calving order. The addition of polyphenols helped to keep monounsaturated (MUFA) and saturated (SFA) levels constant and results in a significant increase in polyunsaturated (PUFA) fatty acid after 15 days of administration. The Omega-6/Omega-3 ratio was in the optimal range. The findings show that inclusion of natural functional food such as plant polyphenols helps to maintain a healthy blood fatty acid profile in lactating dairy cows.