Auswahl der wissenschaftlichen Literatur zum Thema „Oleocanthalic acid“

The health benefits of extra-virgin olive oil (EVOO) are strictly linked to the presence of phenolic compounds, which exhibit numerous nutraceutical properties. In EVOO, the most important class of phenolic compounds is represented by secoiridoids (oleacein and oleocanthal). EVOO is constantly subjected to degradation processes, including hydrolytic and oxidative reactions that influence its phenolic composition. In particular, the hydrolytic reactions determine the transformation of oleocanthal and oleacein into the corresponding phenyl-alcohols, tyrosol, and hydroxytyrosol. Furthermore, oleocanthal by oxidation processes can be converted to oleocanthalic acid. In this study, we evaluated the phenolic composition of three EVOO samples kept at different storage conditions for 15 months, focusing on the variation of oleocanthalic acid content. Specifically, the samples were stored at 4 °C in darkness and at 25 °C with light exposure. The results of our analyses highlighted that in EVOOs exposed to light and maintained at 25 °C, the degradation was more marked than in EVOO stored in dark and at 4 °C, due to the greater influence of external factors on storage conditions. Although chemical–physical characteristics of EVOOs are slightly different depending on provenience and treatment time, the results of this study reveal that storage conditions are fundamental to controlling phenol concentration.

Olive oil phenols (OOPs) are associated with the prevention of many human cancers. Some of these have been shown to inhibit cell proliferation and induce apoptosis. However, no systematic comparative study exists for all the investigated compounds under the same conditions, due to difficulties in their isolation or synthesis. Herein are presented innovative methods for large-scale selective extraction of six major secoiridoids from olive oil or leaves enabling their detailed investigation. The cytotoxic/antiproliferative bioactivity of these six compounds was evaluated on sixteen human cancer cell lines originating from eight different tissues. Cell viability with half-maximal effective concentrations (EC50) was evaluated after 72 h treatments. Antiproliferative and pro-apoptotic effects were also assessed for the most bioactive compounds (EC50 ≤ 50 μΜ). Oleocanthal (1) showed the strongest antiproliferative/cytotoxic activity in most cancer cell lines (EC50: 9–20 μΜ). The relative effectiveness of the six OOPs was: oleocanthal (1) > oleuropein aglycone (3a,b) > ligstroside aglycone (4a,b) > oleacein (2) > oleomissional (6a,b,c) > oleocanthalic acid (7). This is the first detailed study comparing the bioactivity of six OOPs in such a wide array of cancer cell lines, providing a reference for their relative antiproliferative/cytotoxic effect in the investigated cancers.

Reversed-phase liquid chromatography and electrospray ionization with Fourier-transform single and tandem mass spectrometry (RPLC-ESI-FTMS and FTMS/MS) were employed for the structural characterization of oleocanthal (OLEO) and oleacin (OLEA), two of the most important bioactive secoiridoids occurring in extra virgin olive oils (EVOOs). The existence of several isoforms of OLEO and OLEA was inferred from the chromatographic separation, accompanied, in the case of OLEA, by minor peaks due to oxidized OLEO recognized as oleocanthalic acid isoforms. The detailed analysis of the product ion tandem MS spectra of deprotonated molecules ([M-H]−) was unable to clarify the correlation between chromatographic peaks and specific OLEO/OLEA isoforms, including two types of predominant dialdehydic compounds, named Open Forms II, containing a double bond between carbon atoms C8 and C10, and a group of diasteroisomeric closed-structure (i.e., cyclic) isoforms, named Closed Forms I. This issue was addressed by H/D exchange (HDX) experiments on labile H atoms of OLEO and OLEA isoforms, performed using deuterated water as a co-solvent in the mobile phase. HDX unveiled the presence of stable di-enolic tautomers, in turn providing key evidence for the occurrence, as prevailing isoforms, of Open Forms II of OLEO and OLEA, different from those usually considered so far as the main isoforms of both secoiridoids (having a C=C bond between C8 and C9). It is expected that the new structural details inferred for the prevailing isoforms of OLEO and OLEA will help in understanding the remarkable bioactivity exhibited by the two compounds.

Olive oil is an important product in the Mediterranean diet, due to its health benefits and sensorial characteristics. Picholine marocaine is the most cultivated variety in Morocco. The present research aims to evaluate the phenolic compounds, vitamin E and fatty acids of commercial Picholine marocaine virgin olive oils (VOOs) from five different North Moroccan provinces (Chefchaouen, Taounate, Errachidia, Beni Mellal and Taza), using HPLC-photodiode array (PDA)/electrospray ionization (ESI)-MS, normal phase (NP)-HPLC/ fluorescence detector (FLD) and GC-flame ionization detector (FID)/MS, respectively. The obtained results showed an average content of 130.0 mg kg−1 of secoiridoids (oleuropein aglycone, 10-hydroxy-oleuropein aglycone and ligstroside aglycone, oleocanthal and oleacein), 108.1 mg kg−1 of phenolic alcohols (tyrosol and hydroxytyrosol), 34.7 mg kg−1 of phenolic acids (caffeic acid, ferulic acid and elenolic acid), and 8.24 mg kg−1 of flavonoids (luteolin, luteolin glucoside, apigenin). With regard to vitamin E, α-tocopherol was the most abundant vitamin E (57.9 mg kg−1), followed by α-tocotrienol (2.5 mg kg−1), γ-tocopherol (4.5 mg kg−1) and β-tocopherol (1.9 mg kg−1), while δ-tocopherol was not detected. Moreover, 14 fatty acids were found and, among them, oleic acid (76.1%), linoleic acid (8.1%) palmitic acid (8.7%) and stearic acid (2.5%) were the major fatty acids detected. Finally, heat map and principal component analysis allowed us to classify the studied provinces in terms of VOO chemical composition: Chefchaouen (tyrosol and hydroxytyrosol), Taounate (oleuropein aglycone), Errachidia (ferulic acid, w-3 and w-6), Beni Mellal (oleocanthal) and Taza (luteolin and oleic acid).

Four olive oils with varying amounts of total phenols were exposed to four different heating conditions. Chemical parameters such as free fatty acid, peroxide values, UV absorbency, total phenols, individual phenols, α-tocopherol, squalene, oleocanthal, fatty acid profile and smoke point were measured before and after heating to evaluate the impact of heating conditions on the oils. We found olive oils have reasonably high smoke point that is suitable for typical home-cooking conditions and fresh olive oil with low FFA and high phenolics are important for the conservation of olive oil quality and health benefits. A larger degree of oxidation occurred as with increase of heating time and temperature, oils with high level of phenols produced less polar compounds than oils with lower levels of phenols, including refined oils. A significant amount of total phenols and individual phenols such as oleocanthal remained after heating at 121 °C for 10 and 20 minutes, most of squalene stay intact even after heating at 220 °C.

Extra-virgin olive oil (EVOO) and virgin olive oil (VOO) are valuable natural products of great economic interest for their producing countries, and therefore, it is necessary to establish methods capable of proving the authenticity of these oils on the market. This work presents a methodology for the discrimination of olive oil and extra-virgin olive oil from other vegetable oils based on targeted and untargeted high-resolution mass spectrometry (HRMS) profiling of phenolic and triterpenic compounds coupled with multivariate statistical analysis of the data. Some phenolic compounds (cinnamic acid, coumaric acids, apigenin, pinocembrin, hydroxytyrosol and maslinic acid), secoiridoids (elenolic acid, ligstroside and oleocanthal) and lignans (pinoresinol and hydroxy and acetoxy derivatives) could be olive oil biomarkers, whereby these compounds are quantified in higher amounts in EVOO compared to other vegetable oils. The principal component analysis (PCA) performed based on the targeted compounds from the oil samples confirmed that cinnamic acid, coumaric acids, apigenin, pinocembrin, hydroxytyrosol and maslinic acid could be considered as tracers for olive oils authentication. The heat map profiles based on the untargeted HRMS data indicate a clear discrimination of the olive oils from the other vegetable oils. The proposed methodology could be extended to the authentication and classification of EVOOs depending on the variety, geographical origin, or adulteration practices.

Physical parameters (i.e., extraction yield, oil content), chemicals (i.e., fatty acids, phenolics) and oxidative stability associated with virgin olive oil (VOO) from ten varieties in Wudu, China, were analyzed as a function of maturity index and variety by multivariate analysis models. Most of the analytical parameters were significantly affected by the variety and maturity index, and the former was more influential than the latter. Phenolics were the principal factor dividing the ten varieties into four groups. High phenolic levels were observed in the ‘Koroneiki’ group and ‘Manzanilla’ group, but the oil extractability index differentiated between them, being the highest and lowest, respectively. The ‘Koroneiki’ group demonstrated high oil productivity and oil quality, which was worthy of promotion in large-scale cultivation. High amounts of linoleic enhanced the VOO health benefits of ‘Ascolana tenera, Arbequina and Zhongshan24’ group, but brought the risk of shortening the shelf-life. The ‘Ulliri Bardhe, Empeltre, Ezhi8, Yuntai14 and Picual’ group clustered for the higher relative value of oleic acid. The maturity index had significant negative effects on the content of total phenolics, oleacein, oleocanthal, and oleic acid, but had a positive effect on the extractability index, which suggested that varieties with low phenolics and oleic acid levels should be harvested early.

L’olio extravergine d’oliva (Extra-Virgin Olive Oil, EVOO) e l’estratto di foglie d’ulivo (Olive Leaves Extract, OLE) rappresentano un'importante fonte di composti nutraceutici, tra cui si annoverano composti a struttura fenolica e polifenolica come i fenil alcoli, gli acidi fenolici, i lignani, i flavoni, i flavonoli ed i secoiridoidi, una classe di composti esclusivi della famiglia delle Oleaceae. I secoiridoidi principalmente presenti nell’EVOO sono l’oleaceina e l’oleocantale, mentre nelle foglie si ritrova l’oleuropeina. Questi composti possiedono proprietà nutraceutiche, quali quelle antiproliferative, cardioprotettive, antiossidanti ed antinfiammatorie. Il progetto di ricerca della mia tesi di dottorato è stato focalizzato sullo studio dei composti fenolici e polifenolici presenti nell’EVOO e nell’OLE e si è articolato in varie direttrici:  Sviluppo di metodi efficienti per l'estrazione e la purificazione di oleocantale ed oleaceina da EVOOs Durante il dottorato sono state messe a punto delle procedure che hanno permesso di ottimizzare le precedenti metodiche di estrazione e purificazione ottenendo quantità significative di oleaceina ed oleocantale con buona purezza, partendo da EVOO fresco.  Studio delle proprietà nutraceutiche di oleocantale ed oleaceina L’oleocantale e l’oleaceina estratti e purificati dagli EVOOs sono stati sottoposti a studi farmacologici al fine di investigare le loro proprietà nutraceutiche. Questi studi hanno evidenziato il ruolo dei due secoiridoidi nell'infiammazione degli adipociti associata all'obesità e nella via di segnale NF-κB. È stato possibile evidenziare la capacità dell'oleaceina di inibire la proliferazione delle cellule di melanoma cutaneo in vitro (cellule 501Mel). Inoltre, è stato provato che l'oleocantale esercita un effetto anti-fibrotico, sia su modelli in vitro che in vivo di fibrosi epatica.  Studio delle variazioni della composizione fenolica e polifenolica degli EVOOs nel tempo Queste ricerche sono state condotte analizzando differenti EVOOs mediante metodiche HPLC sviluppate in questo dottorato. I risultati di queste analisi hanno confermato che i composti fenolici presenti nell’EVOO subiscono nel tempo un processo idrolitico, che differisce in ciascun campione di EVOO ed è fortemente correlato alle condizioni di conservazione.  Studio di nuovi componenti negli EVOOs e delle loro potenziali proprietà nutraceutiche Tra i pochi studi relativi ai processi ossidativi subiti dai composti fenolici e polifenolici presenti nell’EVOO, recentemente è stato individuato un nuovo prodotto di ossidazione dell’oleocantale, l’acido oleocantalico, che da studi preliminari è risultato essere particolarmente interessante per le sue potenziali proprietà neuroprotettive. La mia attenzione si è quindi focalizzata sull’acido oleocantalico al fine di ottenerlo ad alto grado di purezza, per poterlo poi sottoporre ad ulteriori studi per investigare le sue proprietà nutraceutiche. È stata valutata per la prima volta la sua attività antiossidante, dimostrando che l’acido oleocantalico possiede un’attività radical scavenging di specie reattive dell’ossigeno.  Studio della composizione di EVOOs toscani per la determinazione della loro tracciabilità geografica Questa parte della mia attività è stata svolta nell’ambito di un progetto che si propone di sviluppare un modello che permetta di verificare e garantire l’origine dell’olio, legandolo indissolubilmente al suo territorio di produzione. In particolare, mi sono dedicata allo studio delle caratteristiche di quaranta EVOOs toscani (acidità totale, contenuto dei composti fenolici e dei principali acidi grassi) al fine di correlarle con dati relativi ad altri parametri, quali la concentrazione di macroelementi, microelementi, elementi in traccia essenziali e non essenziali, nonché terre rare, presenti sia nei campioni di EVOOs che in quelli di suolo dove gli ulivi sono stati coltivati.  Sviluppo di device utili nel campo della rigenerazione tissutale a partire da fitoestratti di foglie d’ulivo (OLEs) ottenute da ulivi di Cultivar autoctone toscane Questa parte dell’attività di ricerca è stata svolta nell’ambito di un progetto che ha come obiettivo quello di studiare fibre biocompatibili che incorporano OLEs per lo sviluppo di dispositivi biomedicali utili nel processo di rigenerazione tissutale. Nell’ambito di questo progetto mi sono dedicata all’analisi di diversi OLEs al fine di selezionare quello più appropriato in termini di composizione fenolica e polifenolica, che è stato quindi incorporato nei biopolimeri. Ho quindi confermato l’avvenuta incorporazione dell’OLE nei biopolimeri e verificato che questi fossero in grado di rilasciare i fenoli ed i polifenoli dell’OLE. Inoltre, è stato dimostrato che i biopolimeri che incorporano l’OLE possiedono promettenti proprietà anti-infiammatorie ed immunomodulatorie, utili per il possibile sviluppo dei device.
Extra-virgin olive oil (EVOO) and olive leaves extract (OLE) represent an important source of nutraceutical compounds, including phenolic and polyphenolic compounds such as phenyl alcohols, phenolic acids, lignans, flavones, flavonols and secoiridoids. Secoiridoids are a class of compounds exclusive of Oleaceae family. Oleocanthal and oleacein are the most important secoiridoids present in EVOO, while oleuropein is the main representative in OLE. These compounds possess nutraceutical properties, such as antiproliferative, cardioprotective, antioxidant and anti-inflammatory properties. My PhD project was focused on the study of the phenolic and polyphenolic compounds in EVOO and in OLE and it was aimed to several parallel objectives:  Development of efficient methods for the extraction and the purification of oleocanthal and oleacein from EVOOs During this PhD, new procedures were developed by improving previous extraction and purification methods, obtaining significant quantities of oleacein and oleocanthal from fresh EVOO, with good purity.  Study of the nutraceutical properties of oleocanthal and oleacein Oleocanthal and oleacein extracted and purified from EVOOs were then submitted to pharmacological studies to investigate their nutraceutical properties. The results of these studies highlighted the role of the two secoiridoids in obesity-associated adipocytes inflammation and in the NF-κB pathway. The ability of oleacein to inhibit the proliferation of skin melanoma cells in vitro (501Mel cells) was demonstrated. Moreover, the antifibrotic effect of oleocanthal, in both in vitro an in vivo models of liver fibrosis, was proved.  Study of the variations in the phenolic and polyphenolic composition of EVOOs during storage This study was conducted by analysing several EVOOs using HPLC methods developed during this PhD thesis. The results of these analyses confirmed that the phenolic compounds present in EVOO underwent a hydrolytic process during storage. However, the evolution of this pathway differs in each EVOO sample, and it is strongly related to storage condition.  Study of novel components in EVOOs and their potential nutraceutical properties The oxidative process involving phenolic and polyphenolic compounds in EVOO are poorly investigated. A new oleocanthal oxidation product, named oleocanthalic acid, has been recently identified and preliminary studies showed the potential neuroprotective properties of this compound. My attention was therefore focused on obtaining oleocanthalic acid with high purity in order to submit it to further studies for its nutraceutical properties investigation. A detailed assessment of its in vitro radicals quenching activity was performed for the first time, demonstrating its scavenging capacity against reactive oxygen species.  Study of composition of Tuscan EVOOs for the determination of their geographical traceability This part of my PhD work was carried out as a part of a project aimed to develop a model that would allow to verify and guarantee the origin of the oil, indissolubly linking it to its production area. In particular, I studied the characteristics of forty Tuscan EVOOs (free acidity, phenolic compounds content and main fatty acids content). The results of these analyses will be correlated with other parameters studied, such as the concentration of macro-elements, micro-elements, essential and non-essential trace elements, as well as rare earth elements, present both in the samples of EVOOs and in those of soil where the olive trees were cultivated.  Development of devices useful in tissue regeneration fields from olive leaves phytoextracts (OLEs) obtained from autochthonous Tuscan olive trees Cultivars This part of my research was carried out under a project that aims to study biocompatible fibers incorporating OLEs for the development of biomedical devices useful in the tissue regeneration field. In particular, I analysed the phenolic and polyphenolic composition of several OLEs in order to select the most appropriate one to incorporate into the biopolymers. I therefore confirmed the incorporation of the OLE into the biopolymers and their capability to release the OLE phenols and polyphenols. Furthermore, the biopolymers incorporating OLE showed promising anti-inflammatory and immunomodulatory properties, useful for the development of devices.

The Mediterranean Diet contains fruits, vegetables, nuts, whole grains, fish and virgin olive oil (VOO) as a key component. It is well explained that those consumption has a number of positive health effects. It has been accepted for a long time that the leading compound in olive was oleic acid as a monounsaturated fatty acid. However, the latter researches were figured out that VOO rich in natural phenolics have multifaceted influence on major diseases including cancer, diabetes, cardiovascular diseases, neurodegenerative disease, and metabolic disorders. Recent medical studies proved that oleocanthal and oleacein, characteristic bioactive biophenol-secoiridoids in VOO, success in the anti-inflammatory and in the antioxidant properties, respectively. It has more recently investigated that oleocanthal and hydroxytyrosol (HT) kills cancer cells (CCs). HT and oleuropein reduces breast cancer and cutaneous melanoma cancer cells both in number and aggressiveness, and inhibits CCs multiplying. It has been declared too many times that nutrition type is the strongest factor can be caused acute and chronic diseases. However, at the same time, nutrition can also prevent some of those heavy symptoms. The main purpose of presented chapter is to meet olive’s bioactive molecules and to examine how to improve our health with diet.