Tyrosol, the major extra virgin olive oil compound, restored intracellular antioxidant defences in spite of its weak antioxidative effectiveness

Nutraceutical Valorization of Exhausted Olive Pomace from Olea europaea L. Using Advanced Extraction Techniques

Exhausted olive pomace (EOP) represents the principal residue of olive pomace. Several studies have optimized the extraction of specialized metabolites from the EOP of Olea europaea L., but a comparison between different extractive methods has not been made. For this reason, the present investigation aims to compare four different extractive methods by using water and 15% ethanol/water as extractive solvents. Specifically, based on extract antioxidant activity, the methods compared were maceration (MAC), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and Accelerated Solvent Extraction (ASE). Between these, the UAE and ASE hydroalcoholic EOP extracts were demonstrated to have the highest antioxidant activity. Subsequently, these extracts were investigated for their hypoglycemic and antiradical activity using in vitro cell-free and cell-based assays, respectively. ASE hydroalcoholic EOP extract demonstrated the greatest ability to inhibit the α-amylase enzyme and an in vitro antioxidant activity comparable to N-acetyl cysteine in HepG2 cells. UAE and ASE extracts' phytochemical characterization was also performed, identifying seven phenolic compounds, including 3-hydroxytyrosol, tyrosol, and, for the first time, salidroside. The ASE hydroalcoholic EOP extract was the richest from a phytochemical point of view, thus confirming its major biological activity. Therefore, ASE and 15% ethanol/water may represent the best extractive method for EOP nutraceutical valorization.

Tyrosol blocks E. coli anaerobic biofilm formation via YbfA and FNR to increase antibiotic susceptibility

Bacteria within mature biofilms are highly resistant to antibiotics than planktonic cells. Oxygen limitation contributes to antibiotic resistance in mature biofilms. Nitric oxide (NO) induces biofilm dispersal; however, low NO levels stimulate biofilm formation, an underexplored process. Here, we introduce a mechanism of anaerobic biofilm formation by investigating the antibiofilm activity of tyrosol, a component in wine. Tyrosol inhibits E. coli and Pseudomonas aeruginosa biofilm formation by enhancing NO production. YbfA is identified as a target of tyrosol and its downstream targets are sequentially determined. YbfA activates YfeR, which then suppresses the anaerobic regulator FNR. This suppression leads to decreased NO production, elevated bis-(3'-5')-cyclic dimeric GMP levels, and finally stimulates anaerobic biofilm formation in the mature stage. Blocking YbfA with tyrosol treatment renders biofilm cells as susceptible to antibiotics as planktonic cells. Thus, this study presents YbfA as a promising antibiofilm target to address antibiotic resistance posed by biofilm-forming bacteria, with tyrosol acting as an inhibitor.

Synthesis of lipophilic antioxidant tyrosol laurate using imidazolium ionic liquid [Bmim]HSO4 as a catalyst

Tyrosol is a natural phenolic compound with potent antioxidant properties in the field of food manufacturing. However, the low lipophilicity of tyrosol limited its application. Therefore, the construction of tyrosol laurate (Tyr-L) could effectively overcome the limitations of tyrosol. In this work, four ionic liquids (ILs) were applied for TYr-L preparation. Among them, the 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO4) showed the best catalytic performance. The maximum TYr-L yield was achieved (94.24 ± 1.23 %) under the optimal conditions (reaction temperature 119 °C, substrate ratio 1:6.7, IL dosage 9.2 %, and reaction time 12 h). The kinetic and thermodynamic parameters were also evaluated and it was found that Ea, ΔH, ΔS, and ΔG were 80.81 kJ·mol-1, 77.63 kJ·mol-1, -82.08 J·(mol·K)-1, and 109.89 kJ·mol-1, respectively. The acidic [Bmim]HSO4 demonstrated excellent reusability and stability, even after 6 cycles. Furthermore, TYr-L showed superior ABTS radical scavenging ability, which could be further applied in various industrial processes.

Anti-Cancer, Anti-Angiogenic, and Anti-Atherogenic Potential of Key Phenolic Compounds from Virgin Olive Oil

The Mediterranean diet, renowned for its health benefits, especially in reducing cardiovascular risks and protecting against diseases like diabetes and cancer, emphasizes virgin olive oil as a key contributor to these advantages. Despite being a minor fraction, the phenolic compounds in olive oil significantly contribute to its bioactive effects. This review examines the bioactive properties of hydroxytyrosol and related molecules, including naturally occurring compounds (-)-oleocanthal and (-)-oleacein, as well as semisynthetic derivatives like hydroxytyrosyl esters and alkyl ethers. (-)-Oleocanthal and (-)-oleacein show promising anti-tumor and anti-inflammatory properties, which are particularly underexplored in the case of (-)-oleacein. Additionally, hydroxytyrosyl esters exhibit similar effectiveness to hydroxytyrosol, while certain alkyl ethers surpass their precursor's properties. Remarkably, the emerging research field of the effects of phenolic molecules related to virgin olive oil on cell autophagy presents significant opportunities for underscoring the anti-cancer and neuroprotective properties of these molecules. Furthermore, promising clinical data from studies on hydroxytyrosol, (-)-oleacein, and (-)-oleocanthal urge further investigation and support the initiation of clinical trials with semisynthetic hydroxytyrosol derivatives. This review provides valuable insights into the potential applications of olive oil-derived phenolics in preventing and managing diseases associated with cancer, angiogenesis, and atherosclerosis.

Total transcriptome response for tyrosol exposure in Aspergillus nidulans

Although tyrosol is a quorum-sensing molecule of Candida species, it has antifungal activity at supraphysiological concentrations. Here, we studied the effect of tyrosol on the physiology and genome-wide transcription of Aspergillus nidulans to gain insight into the background of the antifungal activity of this compound. Tyrosol efficiently reduced germination of conidia and the growth on various carbon sources at a concentration of 35 mM. The growth inhibition was fungistatic rather than fungicide on glucose and was accompanied with downregulation of 2199 genes related to e.g. mitotic cell cycle, glycolysis, nitrate and sulphate assimilation, chitin biosynthesis, and upregulation of 2250 genes involved in e.g. lipid catabolism, amino acid degradation and lactose utilization. Tyrosol treatment also upregulated genes encoding glutathione-S-transferases (GSTs), increased specific GST activities and the glutathione (GSH) content of the cells, suggesting that A. nidulans can detoxify tyrosol in a GSH-dependent manner even though this process was weak. Tyrosol did not induce oxidative stress in this species, but upregulated "response to nutrient levels", "regulation of nitrogen utilization", "carbon catabolite activation of transcription" and "autophagy" genes. Tyrosol may have disturbed the regulation and orchestration of cellular metabolism, leading to impaired use of nutrients, which resulted in growth reduction.

Spontaneous fermentation of Maraština wines: The correlation between autochthonous mycobiota and phenolic compounds

Understanding fungal community dynamics during fermentation is important for assessing their influence on wine's phenolic content. The present study represents the first effort to explore the correlation between the autochthonous mycobiota of Maraština grapes collected from Dalmatian winegrowing sub-regions in Croatia and the phenolic composition, as well as the physicochemical parameters of wines produced through spontaneous fermentation. The metataxonomic approach revealed Metschnikowia pulcherrima, Metschnikowia fructicola and Hanseniaspora uvarum as the core mycobiota detected at the initial phase of fermentation. By contrast, Saccharomyces cerevisiae took over the dominance starting from the middle stage of fermentation. The wine's phenolic compounds were revealed by high-performance liquid chromatography, with tyrosol being the most abundant. Rhodotorula babjevae and Botrytis cinerea showed a positive correlation with p-hydroxybenzoic acid, gentisic acid, caffeic acid and cinnamic acid, while demonstrating a negative correlation with protocatechuic acid and chlorogenic acid. Heterophoma novae-verbascicola exhibited the opposite behaviour regarding the same phenolic compounds. The concentration of lactic acid was positively correlated with B. cinerea and negatively correlated with Het. novae-verbascicola. These findings serve as a foundation for in-depth investigations into the role of autochthonous grape mycobiota in phenolic transformation during spontaneous fermentation, potentially leading to the production of high-quality wines with unique terroir characteristics. Future studies should aim to explore the specific role played by individual yeast isolates in the formation of phenolic compounds.

Optimization of tyrosol-producing pathway with tyrosine decarboxylase and tyramine oxidase in high-tyrosine-producing Escherichia coli

Tyrosol (4-hydroxyphenylethanol) is a phenolic compound used in the pharmaceutical and chemical industries. However, current supply methods, such as extraction from natural resources and chemical synthesis, have disadvantages from the viewpoint of cost and environmental protection. Here, we developed a tyrosol-producing Escherichia coli cell factory from a high-tyrosine-producing strain by expressing selected tyrosine decarboxylase-, tyramine oxidase (TYO)-, and medium-chain dehydrogenase/reductase (YahK)-encoding genes. The genes were controlled by the strong T7 promoter and integrated into the chromosome because of the advantages over plasmid-based systems. The strain produced a melanin-like pigment as a by-product, which is suggested to be formed from 4-hydroxyphenylacetaldehyde (a TYO product/YahK substrate). By using a culture medium containing a high concentration of glycerol, which was reported to enhance NADH supply required for YahK activity, the final titer of tyrosol reached 2.42 g/L in test tube-scale cultivation with a concomitant decrease in the amount of pigment. These results indicate that chromosomally integrated and T7 promoter-controlled gene expression system in E. coli is useful for high production of heterologous enzymes and might be applied for industrial production of useful compounds including tyrosine and tyrosol.

The anticancer, anti-oxidant, and antibacterial activities of chitosan-lecithin-coated parthenolide/tyrosol hybrid nanoparticles

Tyrosol (TYR) and parthenolide (PLT) have been used as synthetic antioxidant and natural anticancer compounds. In the current study, we aimed to synthesize an encapsulated complex of both PLT and TYR in a hybrid coating layer consisting of lecithin and chitosan molecules, a proper biocompatible drug delivery system to evaluate its antibacterial and anticancer potentials on human liver HepG2 and pancreatic Panc cancer cell lines. The chitosan-lecithin-coated PLT/TYR nanoparticles (clPT-NPs) were synthesized applying an auto-self-assembling method. The clPT-NPs were characterized utilizing DLS, FTIR, zeta potential, and TEM analysis. The clPT-NPs' antioxidant activity was measured by running ABTS and DPPH antioxidant assays. Moreover, the antibacterial potential of clPT-NPs was evaluated by applying disk diffusion, MIC, and MBC assays. Finally, the nanoparticles' cytotoxicity and apoptotic activity were studied by conducting MTT, Flow cytometry, AO/PI cell staining, and real-time PCR techniques. The clPT-NPs (38 nm) exhibited significant antioxidant activity by inhibiting ABTS and DPPH radicals at 187 and 290 μg/mL IC50 concentrations, respectively. Also, the nanoparticles induced a notable antibacterial activity against Staphylococcus aureus at 0.0625 mg/mL MIC and 0.125 mg/mL MBC concentrations. The clPT-NPs selectively decreased the cancer cells' survival and increased the apoptotic dead cells by up-regulating apoptotic gene expression (BAX and Cas-8) and down-regulating BCL-2 anti-apoptotic gene expression. The PLT toxicity has been merged with improved TYR antioxidant activity, which has been functionalized in a safe, biocompatible hybrid nano-delivery system.

Role of Olive Bioactive Compounds in Respiratory Diseases

Respiratory diseases recently became the leading cause of death worldwide, due to the emergence of COVID-19. The pathogenesis of respiratory diseases is centred around inflammation and oxidative stress. Plant-based alongside synthetic drugs were considered as therapeutics due to their proven nutraceutical value. One such example is the olive, which is a traditional symbol of the MedDiet. Olive bioactive compounds are enriched with antioxidant, anti-inflammatory, anticancer and antiviral properties. However, there are few studies relating to the beneficial effect of olive bioactive compounds on respiratory diseases. A vague understanding of its molecular action, dosage and bioavailability limits its usefulness for clinical trials about respiratory infections. Hence, our review aims to explore olive bioactive compound's antioxidant, anti-inflammatory and antiviral properties in respiratory disease defence and treatment. Molecular insight into olive compounds' potential for respiratory system protection against inflammation and ensuing infection is also presented. Olive bioactive compounds mainly protect the respiratory system by subsiding proinflammatory cytokines and oxidative stress.

The Brain-Gut-Microbiota Interplay in Depression: a key to design innovative therapeutic approaches

Depression is the most prevalent mental disorder in the world associated with huge socio-economic consequences. While depressive-related symptoms are well known, the molecular mechanisms underlying disease pathophysiology and progression remain largely unknown. The gut microbiota (GM) is emerging as a key regulator of the central nervous system homeostasis by exerting fundamental immune and metabolic functions. In turn, the brain influences the intestinal microbial composition through neuroendocrine signals, within the so-called gut microbiota-brain axis. The balance of this bidirectional crosstalk is important to ensure neurogenesis, preserve the integrity of the blood-brain barrier and avoid neuroinflammation. Conversely, dysbiosis and gut permeability negatively affect brain development, behavior, and cognition. Furthermore, although not fully defined yet, changes in the GM composition in depressed patients are reported to influence the pharmacokinetics of common antidepressants by affecting their absorption, metabolism, and activity. Similarly, neuropsychiatric drugs may shape in turn the GM with an impact on the efficacy and toxicity of the pharmacological intervention itself. Consequently, strategies aimed at re-establishing the correct homeostatic gut balance (i.e., prebiotics, probiotics, fecal microbiota transplantation, and dietary interventions) represent an innovative approach to improve the pharmacotherapy of depression. Among these, probiotics and the Mediterranean diet, alone or in combination with the standard of care, hold promise for clinical application. Therefore, the disclosure of the intricate network between GM and depression will give precious insights for innovative diagnostic and therapeutic approaches towards depression, with profound implications for drug development and clinical practice.

Olea europaea Leaf Phenolics Oleuropein, Hydroxytyrosol, Tyrosol, and Rutin Induce Apoptosis and Additionally Affect Temozolomide against Glioblastoma: In Particular, Oleuropein Inhibits Spheroid Growth by Attenuating Stem-like Cell Phenotype

The effects of Olea europaea leaf extract (OLE) phenolics, including oleuropein (OL), hydroxytyrosol (HT), tyrosol (TYR), and rutin against glioblastoma (GB), independently and in combination with temozolomide (TMZ), were investigated in T98G and A172 cells. Cell growth was assessed by WST-1, real-time cell analysis, colony formation, and cell cycle distribution assays. A dual acridine orange propidium iodide (AO/PI) staining and annexin V assay determined cell viability. A sphere-forming assay, an intracellular oxidative stress assay, and the RNA expression of CD133 and OCT4 investigated the GB stem-like cell (GSC) phenotype. A scratch wound-healing assay evaluated migration capacity. OL was as effective as OLE in terms of apoptosis promotion (p < 0.001) and GSC inhibition (p < 0.001). HT inhibited cell viability, GSC phenotype, and migration rate (p < 0.001), but its anti-GB effect was less than the total effect of OLE alone. Rutin decreased reactive oxygen species production and inhibited colony formation and cell migration (p < 0.001). TYR demonstrated the least effect. The additive effects of OL, HT, TYR and rutin with TMZ were significant (p < 0.001). Our data suggest that OL may represent a novel therapeutic approach against GB cells, while HT and rutin show promise in increasing the efficacy of TMZ therapy.

Neuroprotective Panel of Olive Polyphenols: Mechanisms of Action, Anti-Demyelination, and Anti-Stroke Properties

Neurological diseases such as stroke and multiple sclerosis are associated with high morbidity and mortality, long-term disability, and social and economic burden. Therefore, they represent a major challenge for medical treatment. Numerous evidences support the beneficial effects of polyphenols from olive trees, which can alleviate or even prevent demyelination, neurodegeneration, cerebrovascular diseases, and stroke. Polyphenols from olive oils, especially extra virgin olive oil, olive leaves, olive leaf extract, and from other olive tree derivatives, alleviate inflammation and oxidative stress, two major factors in demyelination. In addition, they reduce the risk of stroke due to their multiple anti-stroke effects, such as anti-atherosclerotic, antihypertensive, antioxidant, anti-inflammatory, hypocholesterolemic, hypoglycemic, and anti-thrombotic effects. In addition, olive polyphenols have beneficial effects on the plasma lipid profiles and insulin sensitivity in obese individuals. This review provides an updated version of the beneficial properties and mechanisms of action of olive polyphenols against demyelination in the prevention/mitigation of multiple sclerosis, the most common non-traumatic neurological cause of impairment in younger adults, and against cerebral insult with increasing incidence, that has already reached epidemic proportions.

Dietary EVOO Polyphenols and Gut Microbiota Interaction: Are There Any Sex/Gender Influences?

Accumulating evidence indicates that regular consumption of extra virgin olive oil (EVOO), the main source of fat in the Mediterranean diet, is associated with beneficial health effects and a reduced risk of developing chronic degenerative disorders. The beneficial effects of EVOO can be attributed to its unique composition in monounsaturated fats and phenolic compounds that provide important antioxidant, anti-inflammatory, and immune-modulating activities. On the other hand, it is well known that the gut microbiota has several important roles in normal human physiology, and its composition can be influenced by a multitude of environmental and lifestyle factors, among which dietary components play a relevant role. In the last few years, the two-way interaction between polyphenols, including those in EVOO, and the gut microbiota, i.e., the modulation of the microbiota by polyphenols and that of polyphenol metabolism and bioavailability by the microbiota, has attracted growing attention, being potentially relevant to explain the final effects of polyphenols, as well as of the microbiota profile. Furthermore, sex and gender can affect dietary habits, polyphenol intake, and nutrient metabolism. Lastly, it has been recently suggested that differences in gut microbiota composition could be involved in the unequal incidence of metabolic diseases observed between women and men, due to sex-dependent effects on shaping gut microbiota profiles according to diet. This review summarizes the most recent studies on the relationship between EVOO polyphenols and the gut microbiota, taking into account possible influences of sex and gender in modulating such an interaction.

Ferulic Acid, Pterostilbene, and Tyrosol Protect the Heart from ER-Stress-Induced Injury by Activating SIRT1-Dependent Deacetylation of eIF2α

Disturbances in Endoplasmic Reticulum (ER) homeostasis induce ER stress, which has been involved in the development and progression of various heart diseases, including arrhythmias, cardiac hypertrophy, ischemic heart diseases, dilated cardiomyopathy, and heart failure. A mild-to-moderate ER stress is considered beneficial and adaptative for heart functioning by engaging the pro-survival unfolded protein response (UPR) to restore normal ER function. By contrast, a severe or prolonged ER stress is detrimental by promoting cardiomyocyte apoptosis through hyperactivation of the UPR pathways. Previously, we have demonstrated that the NAD⁺-dependent deacetylase SIRT1 is cardioprotective in response to severe ER stress by regulating the PERK pathway of the UPR, suggesting that activation of SIRT1 could protect against ER-stress-induced cardiac damage. The purpose of this study was to identify natural molecules able to alleviate ER stress and inhibit cardiomyocyte cell death through SIRT1 activation. Several phenolic compounds, abundant in vegetables, fruits, cereals, wine, and tea, were reported to stimulate the deacetylase activity of SIRT1. Here, we evaluated the cardioprotective effect of ten of these phenolic compounds against severe ER stress using cardiomyoblast cells and mice. Among the molecules tested, we showed that ferulic acid, pterostilbene, and tyrosol significantly protect cardiomyocytes and mice heart from cardiac alterations induced by severe ER stress. By studying the mechanisms involved, we showed that the activation of the PERK/eIF2α/ATF4/CHOP pathway of the UPR was reduced by ferulic acid, pterostilbene, and tyrosol under ER stress conditions, leading to a reduction in cardiomyocyte apoptosis. The protection afforded by these phenolic compounds was not directly related to their antioxidant activity but rather to their ability to increase SIRT1-mediated deacetylation of eIF2α. Taken together, our results suggest that ferulic acid, pterostilbene, and tyrosol are promising molecules to activate SIRT1 to protect the heart from the adverse effects of ER stress.

Olive Oil Phenols Prevent Mercury-Induced Phosphatidylserine Exposure and Morphological Changes in Human Erythrocytes Regardless of Their Different Scavenging Activity

Phosphatidylserine (PS) translocation to the external membrane leaflet represents a key mechanism in the pathophysiology of human erythrocytes (RBC) acting as an "eat me" signal for the removal of aged/stressed cells. Loss of physiological membrane asymmetry, however, can lead to adverse effects on the cardiovascular system, activating a prothrombotic activity. The data presented indicate that structurally related olive oil phenols prevent cell alterations induced in intact human RBC exposed to HgCl₂ (5-40 µM) or Ca²⁺ ionophore (5 µM), as measured by hallmarks including PS exposure, reactive oxygen species generation, glutathione depletion and microvesicles formation. The protective effect is observed in a concentration range of 1-30 µM, hydroxytyrosol being the most effective; its in vivo metabolite homovanillic alcohol still retains the biological activity of its dietary precursor. Significant protection is also exerted by tyrosol, in spite of its weak scavenging activity, indicating that additional mechanisms are involved in the protective effect. When RBC alterations are mediated by an increase in intracellular calcium, the protective effect is observed at higher concentrations, indicating that the selected phenols mainly act on Ca²⁺-independent mechanisms, identified as protection of glutathione depletion. Our findings strengthen the nutritional relevance of olive oil bioactive compounds in the claimed health-promoting effects of the Mediterranean Diet.

Engineering a Synthetic Pathway for Tyrosol Synthesis in Escherichia coli

Tyrosol is an aromatic compound with great value that is widely used in the food and pharmaceutical industry. In this study, we reported a synthetic pathway for converting p-coumaric acid (p-CA) into tyrosol in Escherichia coli. We found that the enzyme cascade comprising ferulic acid decarboxylase (FDC1) from Saccharomyces cerevisiae, styrene monooxygenase (SMO), styrene oxide isomerase (SOI) from Pseudomonas putida, and phenylacetaldehyde reductase (PAR) from Solanum lycopersicum could efficiently synthesize tyrosol from p-CA with a conversion rate over 90%. To further expand the range of substrates, we also introduced tyrosine ammonia-lyase (TAL) from Flavobacterium johnsoniae to connect the synthetic pathway with the endogenous l-tyrosine metabolism. We found that tyrosol could be efficiently produced from glycerol, reaching 545.51 mg/L tyrosol in a tyrosine-overproducing strain under shake flasks. In summary, we have established alternative routes for tyrosol synthesis from p-CA (a potential lignin-derived biomass), glucose, and glycerol.

Polyphenols Targeting MAPK Mediated Oxidative Stress and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune disorder, predominantly symmetric, which causes joint inflammation, cartilage degeneration and bone erosion, resulting in deformity and the loss of physical function. Although the management of RA has steadily improved, the pathophysiological mechanism is incompletely elucidated, and therapeutic options are still limited. Due to shortcomings in the efficacy or safety profiles of conventional RA therapies, therapeutic alternatives have been considered. Therefore, natural extracts containing polyphenolic compounds can become promising adjuvant agents for RA global management, due to their antioxidant, anti-inflammatory and apoptotic properties. Polyphenols can regulate intracellular signaling pathways in RA and can generate different immune responses through some key factors (i.e., MAPK, interleukins (ILs 1 and 6), tumor necrosis factor (TNF), nuclear factor light k chain promoter of activated receptor (NF-κB), and c-Jun N-terminal kinases (JNK)). The critical function of the Toll like-receptor (TLR)-dependent mitogen-activating protein kinase (MAPK) signaling pathway in mediating the pathogenic characteristics of RA has been briefly discussed. Oxidative stress can trigger a change in transcription factors, which leads to the different expression of some genes involved in the inflammatory process. This review aims to provide a comprehensive perspective on the efficacy of polyphenols in mitigating RA by inhibiting signaling pathways, suggesting future research perspectives in order to validate their use.

Metabolic profiling and biological activities of the aerial parts of Micromeria imbricata Forssk. growing in Saudi Arabia

The hydroalcoholic extract (MIT) of Micromeria imbricata (Forssk.) growing in Saudi Arabia in addition to the chloroform (MIC) and n-butanol (MIB) fractions were investigated for the first time using UPLC-ESI-MS/MS. The analysis revealed the tentative identification of fifty-eight compounds including three organic acids, twenty-five phenolic compounds, three coumarins, two anthocyanins, twenty-one flavonoids, three terpenes, and one miscellaneous. Moreover, the therapeutic potential of M. imbricata (MIT) and its fractions (MIC and MIB) were determined by in vitro evaluation of their cytotoxic, antioxidant, and anti-obesity characteristics. The MIT extract showed the highest phenolic (125.23 ± 0.87 mg gallic acid equivalent/100 gm extract) and flavonoid (112.24 ± 2.45 mg quercetin equivalent/100 gm extract) contents followed by n-butanol and chloroform fractions. The MIT extract revealed a potent cytotoxic activity against HepG-2 (Hepatocellular carcinoma) and MCF-7 (Breast carcinoma) with IC₅₀ 28.5 ± 2.0 and 35.2 ± 1.2 µg/mL, respectively. Additionally, the tested hydroalcoholic extract exhibited a significant DPPH scavenging activity with SC₅₀ 28.4 ± 1.2 µg/mL and a remarkable lipase inhibitory activity with IC₅₀ 54.2 ± 1.2 µg/mL. In conclusion, the current study presents the first insights into the phytochemical constituents and pharmacological properties of M. imbricata extract and its chloroform and n-butanol fractions. The results revealed that M. imbricata hydroalcoholic extract might be a prolific source of bioactive constituents with potent antioxidant, cytotoxic and anti-obesity potential. It might be a natural alternative therapy and nutritional strategy for obesity treatment.

Tyrosol improves ovalbumin (OVA)-induced asthma in rat model through prevention of airway inflammation

Asthma is an inflammatory disease that affects many people around the world, especially persons at paediatric age group. The effectiveness of tyrosol, a natural phenolic compound, was examined in the asthma model induced by ovalbumin (OVA). For this purpose, four groups, each consisting of eight rats, were arranged. For 21 days, physiological saline solution was treated to the control group and OVA was treated to the groups of OVA, OVA + dexamethasone (Dexa) and OVA + tyrosol groups, intraperitoneally and through inhalation. Additionally, 0.25 mg/kg Dexa was treated to the OVA + Dexa group and 20 mg/kg tyrosol to the OVA + tyrosol group by oral gavage. Serum, blood, bronchoalveolar lavage fluid (BALF) and lung tissues of the rats were examined. It was observed that MDA level decreased, GSH level and GPx activity increased, and there was no change in CAT activity in lung tissues of the tyrosol treatment groups. It was also observed that NF-κB, TNF-α, IL-4, IL-5, IL-13, IFN-γ and IgE levels decreased compared to the OVA group in lung tissue and serum samples except for serum NF-κB and IL-4. However, no effect on IL-1 β level was observed. In addition, it was determined that tyrosol treatment increased the IL-10 level on both tissue samples. The results of the histopathological investigation of lung tissue showed that tyrosol significantly ameliorated OVA-induced histopathological lesions. Additionally, PAS staining showed that mucus hypersecretion was significantly reduced with the use of tyrosol. In addition, it was determined that the number of eosinophils decreased significantly in blood and BALF samples. The obtained results showed that tyrosol possessed antioxidant and anti-inflammatory features on OVA-induced rats and preserved tissue architecture.

Enzymatic oxidation of oleuropein and 3-hydroxytyrosol by laccase, peroxidase, and tyrosinase

The oxidation of oleuropein and 3-hydroxytyrosol by oxidases laccase, tyrosinase, and peroxidase has been studied. The use of a spectrophotometric method and another spectrophotometric chronometric method has made it possible to determine the kinetic parameters Vmax and KM for each enzyme. The highest binding affinity was shown by laccase. The antioxidant capacities of these two molecules have been characterized, finding a very similar primary antioxidant capacity between them. Docking studies revealed the optimal binding position, which was the same for the two molecules and was a catalytically active position. PRACTICAL APPLICATIONS: One of the biggest environmental problems in the food industry comes from olive oil mill wastewater with a quantity of approximately 30 million tons per year worldwide. In addition, olive pomace, the solid residue obtained from the olive oil production, is rich in hydroxytyrosol and oleuropein and the action of enzymatic oxidases can give rise to products in their reactions that can lead to polymerization. This polymerization can have beneficial effects because it can increase the antioxidant capacity with potential application on new functional foods or as feed ingredients. Tyrosinase, peroxidase, and laccase are the enzymes degrading these important polyphenols. The application of a spectrophotometric method for laccase and a chronometric method, for tyrosinase and peroxidase, allowed us to obtain the kinetic information of their reactions on hydroxytyrosol and oleuropein. The kinetic information obtained could advance in the understanding of the mechanism of these important industrial enzymes.

Harnessing the Endogenous 2μ Plasmid of Saccharomyces cerevisiae for Pathway Construction

pRS episomal plasmids are widely used in Saccharomyces cerevisiae, owing to their easy genetic manipulations and high plasmid copy numbers (PCNs). Nevertheless, their broader application is hampered by the instability of the pRS plasmids. In this study, we designed an episomal plasmid based on the endogenous 2μ plasmid with both improved stability and increased PCN, naming it p2μM, a 2μ-modified plasmid. In the p2μM plasmid, an insertion site between the REP1 promoter and RAF1 promoter was identified, where the replication (ori) of Escherichia coli and a selection marker gene of S. cerevisiae were inserted. As a proof of concept, the tyrosol biosynthetic pathway was constructed in the p2μM plasmid and in a pRS plasmid (pRS423). As a result, the p2μM plasmid presented lower plasmid loss rate than that of pRS423. Furthermore, higher tyrosol titers were achieved in S. cerevisiae harboring p2μM plasmid carrying the tyrosol pathway-related genes. Our study provided an improved genetic manipulation tool in S. cerevisiae for metabolic engineering applications, which may be widely applied for valuable product biosynthesis in yeast.

Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Neuroprotective effects of ethanolic extract from dry Rhodiola rosea L. rhizomes

Rhodiola rosea L. rhizome has been used as a traditional medicine to treat fatigue, depression, and cognitive dysfunction. We aimed to authenticate R. rosea L. rhizome using the DNA barcoding technique and to quantify its main compounds, total phenolics, total flavonoids, and antioxidant capacity, and then to investigate their neuroprotective effects. The sequences of internal transcribed spacer and trnH-psbA of R. rosea L. rhizomes showed a 99% identity with those of NCBI GenBank database according to BLAST searches. Analysis using reversed-phase HPLC revealed five main compounds in R. rosea L. rhizome. Rhodiola rosea L. rhizome and two bioactive compounds, salidroside and tyrosol, showed free radical scavenging activity. Rhodiola rosea L. rhizome and its identified compounds protected neuronal PC-12 cells against oxidative stress and showed moderate acetylcholinesterase inhibition. Taken together, these results suggest that R. rosea L. rhizomes with bioactives can be used as a functional ingredient with potential for neuroprotection.

Supplementary information

The online version of this article (doi:10.1007/s10068-020-00868-7) contains supplementary material, which is available to authorized users.

Encapsulation of the Natural Product Tyrosol in Carbohydrate Nanosystems and Study of Their Binding with ctDNA

Tyrosol, a natural product present in olive oil and white wine, possesses a wide range of bioactivity. The aim of this study was to optimize the preparation of nanosystems encapsulating tyrosol in carbohydrate matrices and the investigation of their ability to bind with DNA. The first encapsulation matrix of choice was chitosan using the ionic gelation method. The second matrix was β-cyclodextrin (βCD) using the kneading method. Coating of the tyrosol-βCD ICs with chitosan resulted in a third nanosystem with very interesting properties. Optimal preparation parameters of each nanosystem were obtained through two three-factor, three-level Box-Behnken experimental designs and statistical analysis of the results. Thereafter, the nanoparticles were evaluated for their physical and thermal characteristics using several techniques (DLS, NMR, FT-IR, DSC, TGA). The study was completed with the investigation of the impact of the encapsulation on the ability of tyrosol to bind to calf thymus DNA. The results revealed that tyrosol and all the studied systems bind to the minor groove of ctDNA. Tyrosol interacts with ctDNA via hydrogen bond formation, as predicted via molecular modeling studies and corroborated by the experiments. The tyrosol-chitosan nanosystem does not show any binding to ctDNA whereas the βCD inclusion complex shows analogous interaction with that of free tyrosol.

Cellular Antioxidant Activity of Olive Pomace Extracts: Impact of Gastrointestinal Digestion and Cyclodextrin Encapsulation

Olive pomace is a valuable secondary raw material rich in polyphenols, left behind after the production of olive oil. The present study investigated the protective effect of a polyphenolic extract from olive pomace (OPE) on cell viability and antioxidant defense of cultured human HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (tBOOH). The investigation considered possible matrix effects, impact of gastrointestinal digestion and cyclodextrin (CD) encapsulation. Pre-treatment of cells with OPE prevented cell damage and increased intracellular glutathione but did not affect the activity of glutathione peroxidase and superoxide dismutase. OPE matrix significantly enhanced cell protective effects of major antioxidants, such as hydroxytyrosol (HTS), while cyclodextrin encapsulation enhanced activity of OPE against intracellular reactive oxygen species (ROS) accumulation. The obtained results show that OPE is more potent antioxidant in comparison to equivalent dose of main polyphenols (HTS and TS) and that increasing solubility of OPE polyphenols by CD encapsulation or digestion enhances their potential to act as intracellular antioxidants. Antioxidative protection of cells by OPE was primarily achieved through direct radical-scavenging/reducing actions rather than activation of endogenous defense systems in the cell.

Polar Head Modified Phospholipids by Phospholipase D-Catalyzed Transformations of Natural Phosphatidylcholine for Targeted Applications: An Overview

This review describes the use of phospholipase D (PLD) to perform the transphosphatidylation of the most common natural phospholipid (PL), phosphatidylcholine (PC) to obtain polar head modified phospholipids with real targeted applications. The introduction of different polar heads with distinctive physical and chemical properties such as charge, polarity and dimensions allows the obtainment of very different PLs, which can be exploited in very diverse fields of application. Moreover, the inclusions of a bioactive moiety in the PL polar head constitutes a powerful tool for the stabilization and administration of active ingredients. The use of this biocatalytic approach allows the preparation of compounds which cannot be easily obtained by classical chemical methods, by using mild and green reaction conditions. PLD is a very versatile enzyme, able to catalyze both the hydrolysis of PC to choline and phosphatidic acid (PA), and the transphosphatidylation reaction in the presence of an appropriate alcohol. The yield of production of the desired product and the ratio with the collateral PA formation is highly dependent on parameters such as the nature and concentration of the alcohol and the enzymatic source. The application of PLD catalyzed transformations for the production of a great number of PLs with important uses in medical, nutraceutical and cosmetic sectors will be discussed in this work.

Tyrosol 1,2,3-triazole analogues as new acetylcholinesterase (AChE) inhibitors

The present work proposed the preparation of triazolic analogues of tyrosol, a biophenol found in olive oil and whose wide range of bioactivities has been the target of many studies. We obtained fifteen novel tyrosol derivatives and the compounds of the series were later evaluated as acetylcholinesterase (AChE) inhibitors. The study of AChE inhibition is important for the development of new drugs and pesticides, and especially the research for managing Alzheimer's disease. The most active compound, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (30), showed IC₅₀ value of 14.66 ± 2.29 μmol L^-1. Docking experiments corroborated by kinetic assay are suggestive of a competitive inhibition mechanism. Derivatives interacted with amino acids from the AChE active site associated to the development of Alzheimer's disease. The results indicate that the compounds synthesized have a high potential as prototypes for the development of new acetylcholinesterase inhibitors.

Green Route for the Isolation and Purification of Hyrdoxytyrosol, Tyrosol, Oleacein and Oleocanthal from Extra Virgin Olive Oil

Extra virgin olive oil (EVOO) phenols represent a significant part of the intake of antioxidants and bioactive compounds in the Mediterranean diet. In particular, hydroxytyrosol (HTyr), tyrosol (Tyr), and the secoiridoids oleacein and oleocanthal play central roles as anti-inflammatory, neuro-protective and anti-cancer agents. These compounds cannot be easily obtained via chemical synthesis, and their isolation and purification from EVOO is cumbersome. Indeed, both processes involve the use of large volumes of organic solvents, hazardous reagents and several chromatographic steps. In this work we propose a novel optimized procedure for the green extraction, isolation and purification of HTyr, Tyr, oleacein and oleocanthal directly from EVOO, by using a Natural Deep Eutectic Solvent (NaDES) as an extracting phase, coupled with preparative high-performance liquid chromatography. This purification method allows the total recovery of the four components as single pure compounds directly from EVOO, in a rapid, economic and ecologically sustainable way, which utilizes biocompatible reagents and strongly limits the use or generation of hazardous substances.

High-Level Production of Tyrosol with Noninduced Recombinant Escherichia coli by Metabolic Engineering

Tyrosol is a pharmacologically active phenolic compound widely used in the pharmaceutical and chemical industries. Microbial fermentation has potential value as an environmentally friendly approach to tyrosol production, but suffers from low tyrosol yields and the need for expensive media additives. In this study, Escherichia coli MG1655 was modified by integrating an E. coli codon-optimized version of the Saccharomyces cerevisiae phenylpyruvate decarboxylase gene, named ARO10*, into the lacI locus. The resulting strain (YMGA*) produced 0.14 mM tyrosol from 2% glucose without the need for expensive media supplements. Subsequent deletion of E. coli genes designed to eliminate competing metabolic pathways (feaB, pheA, tyrB) or undesirable gene regulation (tyrR) produced a strain (YMGA*R) that produced 3.11 mM tyrosol. Tyrosol production was then increased to 10.92 mM by increasing the ARO10* copy number to five copies (strain YMG5A*R). Finally, tyrosol production was increased to 28 mM (ca. 3.9 g/L) by optimizing fermentation conditions in a 5 L fermenter. Engineering a productive E. coli strain with high tyrosol titer from glucose using a medium that does not require added amino acids, inducer, or antibiotic provides a solid basis to produce tyrosol through microbial fermentation.

Extra virgin olive oil enhances the hepatic antioxidant defense and inhibits cytogenotoxic effects evoked by 5-hydroxymethylfurfural in mice

This study was performed to assess the ability of the food genotoxicant 5-hydroxymethylfurfural (5-HMF) to induce DNA damage and oxidative injuries in the liver of mice as a possible mechanism of toxic action and to evaluate the role of extra virgin olive oil (EVOO) in inhibiting these injuries. For this purpose, 80 mice were assigned into four equal groups of 20 mice each. Group 1 was kept as control and group 2 was given 5-HMF (250 mg/kg bw) by intraperitoneal (IP) injection 3 times weekly for 4 weeks. Group 3 received EVOO (300 μl/kg bw) orally daily for 4 weeks. Group 4 was co-treated with both 5-HMF (250 mg/kg bw) with IP injection and EVOO (300 μl/kg bw) orally 3 times weekly for 4 weeks. IP injection of 5-HMF resulted in a significant decrease in albumin, globulin, and total protein contents and significant increases in alanine transaminase, aspartate transaminase, and alkaline phosphatase activities. Administration of EVOO alone or with 5-HMF reduced the 5-HMF-induced alterations and restored the liver function biomarkers, antioxidant defense system, and histoarchitecture of the liver to normal values. EVOO also inhibited the genotoxic and apoptotic effects of 5-HMF suggesting that EVOO could provide liver protection through its powerful antioxidant and confirm its good nutriceutical and pharmacological properties.

Influence of Pomace Matrix and Cyclodextrin Encapsulation on Olive Pomace Polyphenols' Bioaccessibility and Intestinal Permeability

Olive pomace is a rich source of biologically active compounds, mainly polyphenols. Recently, an efficient and sustainable cyclodextrin (CD)-enhanced extraction was developed. It enabled a relatively simple formulation of high-quality olive pomace extracts (OPEs) that can be used as alternative sources of olive-derived polyphenols in the nutrition and pharma industries. However, biological effects and nutraceutical potential of OPEs are primarily limited by generally low oral bioavailability of major polyphenols (hydroxytyrosol and its derivatives) that can be significantly influenced by OPE matrix and the presence of CDs in formulation. The major goal of this research was to investigate the impact of complex matrix and different types of CDs on gastrointestinal stability and intestinal permeability of major OPE polyphenols, and provide additional data about mechanisms of absorption and antioxidant activity in gut lumen. Obtained results showed high bioaccessibility but relatively low permeability of OPE polyphenols, which was negatively affected by OPE matrix. CDs improved antioxidant efficiency of tested OPEs and tyrosol gastrointestinal stability. Effects of CDs on permeability and the metabolism of particular OPE polyphenols were CD- and polyphenol-specific.

Extra Virgin Olive Oil Polyphenols: Modulation of Cellular Pathways Related to Oxidant Species and Inflammation in Aging

The olive-oil-centered Mediterranean diet has been associated with extended life expectancy and a reduction in the risk of age-related degenerative diseases. Extra virgin olive oil (EVOO) itself has been proposed to promote a "successful aging", being able to virtually modulate all the features of the aging process, because of its great monounsaturated fatty acids content and its minor bioactive compounds, the polyphenols above all. Polyphenols are mostly antioxidant and anti-inflammatory compounds, able to modulate abnormal cellular signaling induced by pro-inflammatory stimuli and oxidative stress, as that related to NF-E2-related factor 2 (Nrf-2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which have been identified as important modulators of age-related disorders and aging itself. This review summarizes existing literature about the interaction between EVOO polyphenols and NF-κB and Nrf-2 signaling pathways. Reported studies show the ability of EVOO phenolics, mainly hydroxytyrosol and tyrosol, to activate Nrf-2 signaling, inducing a cellular defense response and to prevent NF-κB activation, thus suppressing the induction of a pro-inflammatory phenotype. Literature data, although not exhaustive, indicate as a whole that EVOO polyphenols may significantly help to modulate the aging process, so tightly connected to oxidative stress and chronic inflammation.

Hydroxytyrosol, Tyrosol and Derivatives and Their Potential Effects on Human Health

The Mediterranean diet and olive oil as its quintessential part are almost synonymous with a healthy way of eating and living nowadays. This kind of diet has been highly appreciated and is widely recognized for being associated with many favorable effects, such as reduced incidence of different chronic diseases and prolonged longevity. Although olive oil polyphenols present a minor fraction in the composition of olive oil, they seem to be of great importance when it comes to the health benefits, and interest in their biological and potential therapeutic effects is huge. There is a growing body of in vitro and in vivo studies, as well as intervention-based clinical trials, revealing new aspects of already known and many new, previously unknown activities and health effects of these compounds. This review summarizes recent findings regarding biological activities, metabolism and bioavailability of the major olive oil phenolic compounds—hydroxytyrosol, tyrosol, oleuropein, oleocanthal and oleacein—the most important being their antiatherogenic, cardioprotective, anticancer, neuroprotective and endocrine effects. The evidence presented in the review concludes that these phenolic compounds have great pharmacological potential, however, further studies are still required.

Modular Engineering of Tyrosol Production in Escherichia coli

In this study, we investigated the effects of the different critical genes in the three modules on tyrosol production in Escherichia coli. Coexpression of the yahK and ARO10 genes increased the yield of tyrosol by 10% compared to that of the control. Tyrosol production by E. coli BFPT1 and E. coli BFPA1 was higher by 15.0% and 17.8% than that by the control, respectively, via coordinated expression of key genes from modules 2 and 3. The tyrosol yield of E. coli BFPE2 was 58.3% higher than that of the control (reaching 5.72 mM) when the expression levels of the key genes aroA and tyrA* from module 2 were balanced. The tyrosol yield of E. coli BFPG1 was increased by 52.6% (reaching 5.8 mM) compared to the control via coexpression of modules 1, 2, and 3. This work suggested that microbial production of tyrosol in E. coli has potential for industrial applications.

The Polyphenolic Composition of Extracts Derived from Different Greek Extra Virgin Olive Oils Is Correlated with Their Antioxidant Potency

Olive oil possesses a predominant role in the diet of countries around the Mediterranean basin, whereas it is a known constituent of several sectors of human culture. The polyphenolic composition of olive oil seems to be a key factor in its beneficial biological properties. Based on the above, the aim of this study was to correlate the polyphenolic composition of five extracts derived from a Greek olive oil variety with their antioxidant potency and antimutagenic activities in vitro with chemical-based techniques and cell culture-based assays. According to the results obtained, the polyphenol samples with higher concentration of hydroxytyrosol (HT) were more potent in antioxidant and antimutagenic activity in vitro, as indicated by their ability to scavenge ABTS^·+ radical and to protect the strand of plasmid DNA from free radical-induced breaking compared to the corresponding samples with higher levels of tyrosol (T) and its derivatives. However, this observation was not evident in the cell culture model (i.e., the HeLa cervical cancer cell line) to which the tested extracts were administered. Specifically, the T-rich extracts more effectively increased endogenous GSH levels measured by flow cytometry than did the HT-rich compounds. Also, olive oil compounds contributed variously to the expression of genes implicated in the cell antioxidant machinery, as indicated by quantitative PCR. Therefore, the relationship between structure and function in redox regulation is complex and merits the combination of tests. Given that factors like the production and storage regimen of the plants are major determinants of the composition of the generated extracts, we propose that specific conditions should be adopted in order to achieve their maximum biological activity. These results followed by others in the same direction could provide a solid basis for the production of functional foods enriched in olive oil extracts with potential antioxidant action in vivo.

Wine and Olive Oil Phenolic Compounds Interaction in Humans

Extra virgin olive oil (EVOO) and red wine (RW) are two basic elements that form part of the so-called Mediterranean diet. Both stand out because of their high phenolic compound content and their potential related health benefits. The present study is focused on the metabolic disposition of resveratrol (RESV), tyrosol (TYR), and hydroxytyrosol (HT) following the consumption of EVOO, RW, and a combination of both. In this study, 12 healthy volunteers consumed a single dose of 25 mL of EVOO, 150 mL of RW, and a combination of both in a crossover randomized clinical trial. Urinary recovery of RESV, TYR, and HT was analysed in urine samples collected over a 6-h period following the intake of each treatment. Higher HT levels were observed following EVOO compared to RW (3788 ± 1751 nmols and 2308 ± 847 nmols respectively). After the combination of EVOO and RW, the recovery of TYR and HT metabolites increased statistically compared to their separate consumption (4925 ± 1751 nmols of TYR and 6286 ± 3198 nmols of HT). EVOO triggered an increase in glucuronide conjugates, while RW intake raised sulfate metabolites. Marginal effects were observed in RESV increased bioavailability after the combination of RW with the fat matrix provided by EVOO.

Modulation of intestinal epithelium homeostasis by extra virgin olive oil phenolic compounds

Extra virgin olive oil polyphenols concentrate at the intestinal level and, by modulating the microbiota, oxidative status and inflammation, contribute to prevent the onset or delay the progression of inflammatory/degenerative diseases.

Mediterranean Diet, Food Consumption and Risk of Late-Life Depression: The Mugello Study

OBJECTIVES

To investigate eating habits and adherence to Mediterranean Diet (MD) in relation to the risk of depression in a cohort of nonagenarians enrolled within the Mugello Study, an epidemiological study aimed at investigating both clinically relevant geriatric items and various health issues, including those related to nutritional status.

DESIGN

Cross-sectional study.

SETTING

Homes and nursing homes in the Mugello area, Florence, Italy.

PARTICIPANTS

Subjects aged 90-99 years [N=388 (271F; 117M) mean age: 92.7±3.1].

MEASUREMENTS

All subjects were evaluated through questionnaires and instrumental examinations. Adherence to MD was assessed through the Mediterranean Diet Score. A shorter version of the Geriatric Depression Scale (GDS) was used to detect the possible presence of depressive symptoms. In addition, cognitive and functional status was assessed using the Mini-Mental State Examination, the Clock Drawing Test, as well as the Basic and Instrumental Activities of Daily Living test.

RESULTS

Depressed subjects (DS) (GDS score≥5, 43.8%) were older, females and widows, than non-depressed subjects (NDS). DS reported a slightly but not statistically significant lower MD score than NDS (33.9±3.9 vs. 34.6±3.3, p=0.149). Subjects who reported to consume a greater amount of olive oil and fruit were associated with a lower risk of depression (OR=0.35, 95%CI=0.20-0.59, p<0.001 and OR=0.46, 95%CI=0.26-0.84, p=0.011, respectively) after adjustment for many possible confounders. Similar results were obtained for women, while no statistically significant differences emerged for men.

CONCLUSION

Our results support the hypothesis that a diet rich in olive oil and fruit, characteristics of MD, may protect against the development of depressive symptoms in older age.

Enzymatic Synthesis of a Novel Neuroprotective Hydroxytyrosyl Glycoside

The eco-friendly synthesis of non-natural glycosides from different phenolic antioxidants was carried out using a fungal β-xylosidase to evaluate changes in their bioactivities. Xylosides from hydroquinone and catechol were successfully formed, although the best results were obtained for hydroxytyrosol, the main antioxidant from olive oil. The formation of the new products was followed by thin-layer chromatography, liquid chromatography, and mass spectrometry. The hydroxytyrosyl xyloside was analyzed in more detail, to maximize its production and evaluate the effect of glycosylation on some hydroxytyrosol properties. The synthesis was optimized up to the highest production reported for a hydroxytyrosyl glycoside. The structure of this compound was solved by two-dimensional nuclear magnetic resonance and identified as 3,4-dihydroxyphenyl-ethyl-O-β-d-xylopyranoside. Evaluation of its biological effect showed an enhancement of both its neuroprotective capacity and its ability to ameliorate intracellular levels of reactive oxygen species.

Enzymatic alkylsuccinylation of tyrosol: Synthesis, characterization and property evaluation as a dual-functional antioxidant

This work reports a novel approach to generate a new group of tyrosol-based amphiphilic lipid alkylsuccinylated tyrosol by lipase-catalyzed succinylation of tyrosol with alkylsuccinic anhydrides of varying alkyl chain lengths, in high yields (80-95%). The structures of the compounds were confirmed by MS, FTIR &¹H NMR; and their properties were characterized by Temperature-Ramp FTIR, DSC & CMC measurements. The synthesized compounds integrate water-soluble phenylethanoid and hydrophobic alkyl into one molecule thus are endowed with dual functions: retaining the antioxidant property of tyrosol and entailing tyrosol with new surface-active property. The DPPH activity of tyrosol (13.77%) was significantly enhanced by 2-dodecen-1-ylsuccinylated tyrosol (16.01%). Compared to tyrosol-based emulsions (76.63%), the lipid oxidation is reduced to 21.57% and 42.32% in 2-octen-1-ylsuccinylated/2-dodecen-1-ylsuccinylated tyrosol emulsions, respectively. This work brings new members to the library of functional lipid excipients and open a novel and effective synthetic pathway for derivation of phenyl alcohols.