The huge interest in the health-related properties of foods to improve health has brought about the development of sensitive analytical methods for the characterization of natural products with functional ingredients. Greek olive leaves and drupes constitute a valuable source of biophenols with functional properties. A novel ultra-high-performance liquid chromatography-quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS) analytical method was developed to identify biophenols through target and suspect screening in Greek olive leaves and drupes of the varieties: Koroneiki, Throumbolia, Konservolia, Koutsourelia, Kalamon, Petrolia, Amigdalolia, Megaritiki, Mastoeidis, Agouromanakolia, Agrilia, Adramitiani and Kolovi. The method's performance was evaluated using the target compounds: oleuropein, tyrosol and hydroxytyrosol. The analytes demonstrated satisfactory recovery efficiency for both leaves (85.9-90.5%) and drupes (89.7-92.5%). Limits of detection (LODs) were relatively low over the range 0.038 (oleuropein)-0.046 (hydroxytyrosol) and 0.037 (oleuropein)-0.048 (hydroxytyrosol) for leaves and drupes, respectively For leaves, the precision limit ranged between 4.7 and 5.8% for intra-day and between 5.8 and 6.5% for inter-day experiments, and for drupes, it ranged between 3.8 and 5.2% for intra-day and between 5.1 and 6.2% for inter-day experiments, establishing the good precision of the method. The regression coefficient (r²) was above 0.99 in all cases. Furthermore, the preparation of herbal tea from olive leaves is suggested after investigating the optimum infusion time of dried leaves in boiling water. Overall, 10 target and 36 suspect compounds were determined in leaves, while seven targets and thirty-three suspects were identified in drupes, respectively.

Keywords: Greek; LC-QTOF-MS; biomarkers; drupes; metabolomics; oleuropein; olive leaves; phenolics; suspect.

Subsequent inflammation in stroke plays an important role in the damage of neurons in the perilesional area. Therapeutic intervention targeting inflammation may be a promising complementary strategy to current treatments of stroke. Here, we explored the possible beneficial effects of tyrosol, a derivative of phenethyl alcohol and natural antioxidant, playing an anti-inflammatory role in astrocyte culture and in vitro oxygen glucose deprivation (OGD) model. MTT, western blot, ELISA and EMSA assays were carried out to investigate cell viability, protein expression level, cytokine expression and NF-κB activity. We found tyrosol protected cultured astrocytes against OGD-induced cell viability loss in MTT test. Meanwhile, tyrosol attenuated the released TNF-α and IL-6 level from astrocyte via regulating Janus N-terminal kinase (JNK). The reduction of cytokines from astrocyte might be due to its inhibition of astrocyte activation and regulation of STAT3 signaling pathway since tyrosol attenuated the expression level of GFAP (glial fibrillary acidic protein) and the phosphorylation of STAT3. Additionally, we demonstrated that tyrosol prevented the degradation of IκBα and the increase of IκBα phosphorylation in astrocytes exposed to OGD, which led to the suppression of NF-κB function during ischemia. Collectively, our results showed that tyrosol may be a promising complementary treatment compound for stroke via modulating the inflammatory response in astrocytes during ischemia.

The current management of alperujo as the main solid by-product from the two-phase olive oil extraction system has led to the appearance of a new liquid effluent that until now was treated together with the alperujo itself. The composition and antioxidant properties of its bioactive components at different depths of the pond were studied using colorimetric and HPLC with UV and MS detectors, DPPH, reducing power and rancimat. The concentration of suspended solids varied between 1.71 and 8.49 g/L, total fat was between 0.74 and 1.47 g/L, and total phenols were found between 3.74 and 4.11 g/L, which included hydroxytyrosol, 3,4-dihydroxyphenylglycol and tyrosol as the main phenols. Two types of extracts were obtained through two industrial systems with ethyl acetate and by chromotography, with an average content in total sugars of 2.1% and 3.16%, total phenols of 17.9% and 28.6% and hydroxytyrosol of 51.5 and 79.0 mg/g of extract, respectively. The activity presented by the chromatographic extract was higher in terms of free radical sequestering capacity, reducing power and the inhibition of lipid oxidation. Obtaining bioactive extracts would improve the formulation of food with natural components and at the same time would be the first step in a biorefinery to improve the management of the new effluent.

Keywords: 3,4-dihydroxyphenylglycol; alperujo; antioxidant; functional foods; hydroxytyrosol; olive oil; phenolic extracts.

Meat lipids oxidation during digestion gives rise to a post-prandial oxidative stress condition, which negatively affects human health. Mediterranean Diet vegetables contain high amount of phenolic compounds, which potentially may reduce the oxidative phenomena during digestion. In vitro co-digestion of turkey meat with a typical Mediterranean Diet salad containing tomato, onion, black olives, extra-virgin olive oil (EVOO) and basil, dose-dependently reduced lipid peroxidation. Onion and EVOO were more effective in limiting oxidation than the other foods, resulting in negligible concentrations of lipid hydroperoxides after digestion. Specific phenolic classes dominated the phenolic profile of the different foods, such as flavonols and anthocyanins in onion, phenolic acids in tomato and basil, and tyrosol-derivatives in black olives and EVOO. The correlation between lipid peroxidation inhibition, phenolic constituents and antioxidant properties was evaluated by principal component analysis (PCA). Flavonols and anthocyanin were the major contributors to the bioactive response of vegetable foods.

OBJECTIVE

To study the chemical constituents from the husk of Xanthoceras sorbifolia Bunge. Repeated column chromatography on silica gel and preparative TLC were used to isolate the compounds whose structures were elucidated based on spectroscopic data (ESIMS, EIMS, 1D and 2D NMR).

RESULTS

A new alkaloid was isolated and identified as: 2-methyl-6-(2', 3', 4'-trihydroxybutyl)-pyrazine (I), along with nine known compounds: cleomiscosin D (II), naringenin (III), eriodictyol (IV), kaempferol (V), quercetin (VI), rutin (VII), 5,7-dihydroxychromone (VIII), tyrosol (IX), 1-O-methyl-myo-inositol (X).

CONCLUSIONS

Compound I is a new alkaloid, compounds II, IV, V, VII - X were isolated from this genus for the first time.

Virgin olive oil is a characteristic component and the main source of fat of the Mediterranean diet. It is a mix of high-value health compounds, including monounsaturated fatty acids (mainly oleic acid), simple phenols (such as hydroxytyrosol and tyrosol), secoiridoids (such as oleuropein, oleocanthal), flavonoids, and terpenoids (such as squalene). Olive oil consumption has been shown to improve different aspects of human health and has been associated with a lower risk of cancer. However, the underlying cellular mechanisms involved in such effects are still poorly defined, but seem to be related to a promotion of apoptosis, modulation of epigenetic patterns, blockade of cell cycle, and angiogenesis regulation. The aim of this review is to update the current associations of cancer risk with the Mediterranean diet, olive oil consumption and its main components. In addition, the identification of key olive oil components involved in anticarcinogenic mechanisms and pathways according to experimental models is also addressed.

Keywords: cancer; fatty acids; mediterranean diet; olive oil; phenolic compounds.

The extent of phenolic compounds' biodegradation was assessed utilizing un-treated olive mill wastewater (OMWW) fed to a high-rate thermophilic (55 ^οC) anaerobic upflow packed bed reactor (UPBR) and digester effluents (DEs) collected in different hydraulic retention times (HRTs) under steady-state operating conditions. In parallel, the toxicity of each sample was evaluated by performing the microbiotest Thamnotoxkit F™. The outcomes indicate complete biodegradation of 6 phenolic compounds-vanillic acid (VA), caffeic acid (CA), syringic acid (SA), o-coumaric acid (o-CA), oleuropein (OLEU), 4-ethylphenol (4-EP)-and notable removals of hydroxytyrosol (HT) and tyrosol (TYR), reaching up to 94.87 ± 0.04% and 93.92 ± 0.33%, respectively. 4-hydroxybenzoic acid (PHBA), p-coumaric acid (p-CA) and 3,4-dihydroxybenzoic acid (DBA) were recognized as the most recalcitrant and persistent compounds in the anaerobic effluents, being capable of modulating the toxic potential of DEs.

Phenolic compounds occur in a variety of plants and can be used as model compounds for investigating the fate of organic wastewater, lignin, or soil organic matter in the environment. The aim of this study was to better understand and differentiate mechanisms associated with photo- and biodegradation of tyrosol, vanillin, vanillic acid, and coumaric acid in soil. In a 29 d incubation experiment, soil spiked with these phenolic compounds was either subjected to UV irradiation under sterile conditions or to the native soil microbial community in the dark. Changes in the isotopic composition (δ¹³C) of phenolic compounds were determined by gas chromatography-isotope ratio mass spectrometry and complemented by concentration measurements. Phospholipid-derived fatty acid and ergosterol biomarkers together with soil water repellency measurements provided information on soil microbial and physical properties. Biodegradation followed pseudo-first-order dissipation kinetics, enriched remaining phenolic compounds in ¹³C, and was associated with increased fungal rather than bacterial biomarkers. Growing mycelia rendered the soil slightly water repellent. High sample variation limited the reliable estimation of apparent kinetic isotope effects (AKIEs) to tyrosol. The AKIE of tyrosol biodegradation was 1.007 ± 0.002. Photooxidation kinetics were of pseudo-zero- or first-order with an AKIE of 1.02 ± 0.01 for tyrosol, suggesting a hydroxyl-radical mediated degradation process. Further research needs to address δ¹³C variation among sample replicates potentially originating from heterogeneous reaction spaces in soil. Here, nuclear magnetic resonance or nanoscopic imaging could help to better understand the distribution of organic compounds and their transformation in the soil matrix.

The European food legislation authorizes the use of certain health claims based on a scientific basis. This study aimed to evaluate the fatty acid, tocopherol, and polar phenol composition of virgin olive oil (VOO) from cv. Chondrolia Chalkidikis and Chalkidiki regarding the fulfillment of official requirements for the health claims of 'oleic acid', 'vitamin E', and 'olive oil polyphenols'. The examination of representative industrial VOOs from 15 olive mills of the Chalkidiki regional unit showed that the two cultivars yield oils contained the necessary concentrations of the responsible bioactive compounds. This evidence was further substantiated by a four harvest study whereby olives from different maturity stages were sampled from three olive groves. Oils were extracted at a laboratory scale and examined for their content in the above-mentioned three categories of constituents. Oils produced at industrial scale from olives harvested on the 'technological optimum' stage according to the olive grove proprietor were also analyzed. Extra virgin olive oil of the studied cultivars can safely bear the generic claims for 'oleic acid' and 'vitamin E'. The cultivars present great potential regarding the total hydroxytyrosol and tyrosol content of the extracted oil required to attain the third health claim that may be influenced negatively by manufacturing practices.

Keywords: Chalkidiki cultivar; Chondrolia Chalkidikis cultivar; health claims; maturity index; oleic acid; olive oil phenols; total hydroxytyrosol and tyrosol content; virgin olive oil; vitamin E.

The higher alcohols 2-phenylethanol, tryptophol, and tyrosol are a group of yeast-derived compounds that have been shown to affect the aroma and flavour of fermented beverages. Five variants of the industrial wine strain AWRI796, previously isolated due to their elevated production of the 'rose-like aroma' compound 2-phenylethanol, were characterised during pilot-scale fermentation of a Chardonnay juice. We show that these variants not only increase the concentration of 2-phenylethanol but also modulate the formation of the higher alcohols tryptophol, tyrosol, and methionol, as well as other volatile sulfur compounds derived from methionine, highlighting the connections between yeast nitrogen and sulfur metabolism during fermentation. We also investigate the development of these compounds during wine storage, focusing on the sulfonation of tryptophol. Finally, the sensory properties of wines produced using these strains were quantified at two time points, unravelling differences produced by biologically modulating higher alcohols and the dynamic changes in wine flavour over aging.

Keywords: QDA; aging; amino acid; aroma; sulfur; wine; yeast.

Consumption of rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the poly(phenolic) profile and in vitro antioxidant capacity of infusions prepared from red ('fermented', oxidized) and green ('unfermented', unoxidized) rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green rooibos and boiled-brewed red rooibos. However, boiling green and red rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of rooibos tea.

BACKGROUND

The aim of this work was to find the effect of polyphenolic compounds in Basque ciders on the following parameters: antioxidant activity, browning, protein-precipitating capacity, turbidity and reduction potential. These five parameters are highly important, as they affect the taste, the visual aspect and the preservation of cider, and are mainly related to polyphenolic compounds.

RESULTS

Procyanidin B1 and procyanidin B2 showed a significant positive effect on antioxidant activity. p-Coumaric acid, (-)-epicatechin and hyperin had a significant positive effect on protein-precipitating capacity. Tyrosol had a significant negative effect on reduction potential.

CONCLUSIONS

Procyanidin B1 and procyanidin B2 are the most powerful antioxidants in Basque cider, while p-coumaric acid, (-)-epicatechin and hyperin are those with greatest capacity to precipitate proteins. Ciders with higher tyrosol concentration will have less reduction potential and higher antioxidant reservoir.

Theoretical and experimental studies on the energetic, structural and some other relevant physicochemical properties of the antioxidant tyrosol (1), hydroxytyrosol (1OH) molecules and the corresponding radicals 1rad• and 1Orad• are reported in this work. The experimental values of the gas-phase enthalpy of formation, Δf Hm0(g), in kJ·mol-1, of 1 (-302.4 ± 3.4) and 1OH (-486.3 ± 4.1) have been determined. Quantum chemical calculations, at DFT (M05-2X) and composite ab initio G3 and G4 levels of theory, provided results that served to (i) confirm the excellent consistency of the experimental measurements performed, (ii) establish that the stabilizing effect of H-bond of hydroxyethyl chain and aromatic ring (OH···π interaction) is smaller in radicals than in parent molecules, (iii) deduce-combining experimental data in isodesmic reactions-Δf Hm0(g) of radicals 1rad• (-152.3 ± 4.4 kJ·mol-1) and 1Orad• (-370.6 ± 3.8 kJ·mol-1), (iv) estimate a reliable O-H bond dissociation enthalpy, BDE of 1 (368.1 ± 5.6 kJ·mol-1) and of 1OH (333.7 ± 5.6 kJ·mol-1), and (v) corroborate-using "BDE criteria"-than 1OH is a more effective antioxidant than 1.

Roseroot (Rhodiola rosea L.) is a medicinal plant with adaptogenic properties and several pharmaceutically important metabolites. In this study, a full length cDNA encoding a UDPG gene of roseroot was identified, cloned and characterized. Its ORF (1425 bp) was transferred into E. coli, where the expression of the recombinant enzyme was confirmed. To monitor the enzyme activity, 3 precursors (tyramine, 4-hydroxyphenylpyruvate & tyrosol) of salidroside biosynthesis pathway were added to roseroot callus cultures and samples were harvested after 1, 6, 12, 24, 48 & 96 h. Along with the controls (without precursor feeding), each sample was subjected to HPLC and qRT-PCR for phytochemical and relative UDP-glycosyltransferase gene expression analysis, respectively. The HPLC analysis showed that the salidroside content significantly increased; reaching 0.5% of the callus dry weight (26-fold higher than the control) after 96 h when 2 mM tyrosol was given to the media. The expression of the UDP-glycosyltransferase increased significantly being the highest at 12 h after the feeding. The effect of tyramine and 4-hydroxyphenylpyruvate was not as pronounced as of tyrosol. Here, we introduce a R. rosea specific UDPG gene and its expression pattern after biotransformation of intermediate precursors in in vitro roseroot callus cultures.

The indiscriminate use of biocides for general disinfection has contributed to the increased incidence of antimicrobial tolerant microorganisms. This study aims to assess the potential of seven phytochemicals (tyrosol, caffeic acid, ferulic acid, cinnamaldehyde, coumaric acid, cinnamic acid and eugenol) in the control of planktonic and sessile cells of Staphylococcus aureus and Escherichia coli. Cinnamaldehyde and eugenol showed antimicrobial properties, minimum inhibitory concentrations of 3-5 and 5-12 mM and minimum bactericidal concentrations of 10-12 and 10-14 mM against S. aureus and E. coli, respectively. Cinnamic acid was able to completely control adhered bacteria with effects comparable to peracetic acid and sodium hypochlorite and it was more effective than hydrogen peroxide (all at 10 mM). This phytochemical caused significant changes in bacterial membrane hydrophilicity. The observed effectiveness of phytochemicals makes them interesting alternatives and/or complementary products to commonly used biocidal products. Cinnamic acid is of particular interest for the control of sessile cells.

Gastric ulceration is among the most serious humanpublic health problems. <i>Olea europea</i> L. cv. Arbequina is one of the numerous olive varieties which have scarcely been studied. The reported antioxidant and anti-inflammatory potential of the olive plant make it a potential prophylactic natural product against gastric ulcers. Consequently, the main goal of this study is to investigate the gastroprotective effect of <i>Olea europea</i> L. cv. Arbequina leaf extract. LC-HRMS-based metabolic profiling of the alcoholic extract of <i>Olea europea</i> L. cv. Arbequina led to the dereplication of 18 putative compounds (<b>1</b>-<b>18</b>). In vivo indomethacin-induced gastric ulcer in a rat model was established and the <i>Olea europea</i> extract was tested at a dose of 300 mg kg^-1 compared to cimetidine (100 mg kg^-1). The assessment of gastric mucosal lesions and histopathology of gastric tissue was done. It has been proved that <i>Olea europea</i> significantly decreased the ulcer index and protected the mucosa from lesions. The antioxidant potential of the extract was evaluated using three in vitro assays, H₂O₂ scavenging, xanthine oxidase inhibitory, and superoxide radical scavenging activities and showed promising activities. Moreover, an in silico based study was performed on the putatively dereplicated compounds, which highlighted that 3-hydroxy <em>tyrosol</em> (<b>4</b>) and oleacein (<b>18</b>) can target the 5-lipoxygenase enzyme (5-LOX) as a protective mechanism against the pathogenesis of ulceration. Upon experimental validation, both compounds 3-hydroxy <em>tyrosol</em> (HT) and oleacein (OC) (<b>4</b> and <b>18</b>, respectively) exhibited a significant in vitro 5-LOX inhibitory activity with IC₅₀ values of 8.6 and 5.8 µg/mL, respectively. The present study suggested a possible implication of <i>O. europea</i> leaves as a potential candidate having gastroprotective, antioxidant, and 5-LOX inhibitory activity for the management of gastric ulcers.

Keywords: 5-lipoxygenase; Olea europea; antioxidant; gastro-protective; metabolic profiling.

A rapid analytical method for the determination of phenylethanoids content in extra virgin olive oil has been developed. The method intends to address the European regulation EU 432/2012 on health claims, which allows to report on the front label of olive oil, the positive health effects due to the consumption of this food. The innovative method is based on paper spray tandem mass spectrometry using deuterated standards. It relies on a two-step analysis, needed to assess the free form of tyrosol and hydroxytyrosol and their ester conjugates after hydrolysis treatment. Different olive oil samples have been analyzed and the classical analytical parameters such as accuracy, LOQ and LOD were calculated from fortified samples. The good values of the latters show the reliability of the new approach, that limits the time of analysis and sample preparation to few minutes.

Chitosan is receiving increasing attention from the food industry for being a biodegradable, non-toxic, antimicrobial biopolymer able to extend the shelf life of, and preserve the quality of, fresh food. However, few studies have investigated the ability of chitosan-based coatings to allow the diffusion of bioactive compounds into the food matrix to improve its nutraceutical quality. This research is aimed at testing whether a hydrophilic molecule (tyrosol) could diffuse from the chitosan-tyrosol coating and cross the tomato peel. To this end, in vitro permeation tests using excised tomato peel and an in vivo application of chitosan-tyrosol coating on tomato fruit, followed by tyrosol quantification in intact fruit, peel and flesh during a seven-day storage at room temperature, were performed. Both approaches demonstrated the ability of tyrosol to permeate across the fruit peel. Along with a decreased tyrosol content in the peel, its concentration within the flesh was increased, indicating an active transfer of tyrosol into this tissue. This finding, together with the maintenance of constant tyrosol levels during the seven-day storage period, is very promising for the use of chitosan formulations to produce functional tomato fruit.

Keywords: antioxidants; carotenoids; chitosan; edible coatings; phenolic compounds; tomato fruit; tyrosol.

Aim: Tyrosol, a quorum sensing molecule in yeasts, was reported to reduce lag phase and induces hyphae formation during cell proliferation. However, evidence of any enhancing effect of tyrosol in cellular proliferation within fermentative environment is unclear. In this investigation, selected yeast cells were assessed for their ability to synthesize tyrosol followed by examining the role of the molecule during fermentation.

Methods and results: Tyrosols were characterized in four fermentative yeasts viz., Saccharomyces cerevisiae, Wickerhamomyces anomalous, Candida glabrata and Candida tropicalis isolated from traditional fermentative cakes of northeast India. All the isolates synthesized tyrosol while C. tropicalis exhibited filamentous growth in response to tyrosols retrieved from other isolates. Purified tyrosols showed protective behaviour in C. tropicalis and S. cerevisiae under ethanol mediated oxidative stress. During fermentation, tyrosol significantly enhanced growth of W. anomalus in starch medium while C. tropicalis exhibited growth enhancement in starch and glucose sources. The chief fermentative yeast S. cerevisiae showed notable enhancement in fermentative capacity in starch medium under the influence of tyrosol con-commitment of ethanol production.

Conclusion: The study concludes that tyrosol exerts unusual effect in cellular growth and fermentative ability of both Saccharomyces and non-Saccharomyces yeasts.

Significance and impact of the study: This is the first report of expression of tyrosol by non-conventional yeasts, where the molecule was found to exert enhancing effect during fermentation thereby augmenting the process of metabolite production during traditional fermentation.

Keywords: Yeast; ethanol fermentation; morphogenesis; quorum sensing; tyrosol.

The Mediterranean diet (MD) is a combination of foods mainly rich in antioxidants and anti-inflammatory nutrients that have been shown to have many health-enhancing effects. Extra-virgin olive oil (EVOO) is an important component of the MD. The importance of EVOO can be attributed to phenolic compounds, represented by phenolic alcohols, hydroxytyrosol, and tyrosol, and to secoiridoids, which include oleocanthal, oleacein, oleuropein, and ligstroside (along with the aglycone and glycosidic derivatives of the latter two). Each secoiridoid has been studied and characterized, and their effects on human health have been documented by several studies. Secoiridoids have antioxidant, anti-inflammatory, and anti-proliferative properties and, therefore, exhibit anti-cancer activity. This review summarizes the most recent findings regarding the pharmacological properties, molecular targets, and action mechanisms of secoiridoids, focusing attention on their preventive and anti-cancer activities. It provides a critical analysis of preclinical, in vitro and in vivo, studies of these natural bioactive compounds used as agents against various human cancers. The prospects for their possible use in human cancer prevention and treatment is also discussed.

Keywords: cancer; ligstroside; oleacein; oleocanthal; oleuropein; secoiridoids.

Soluble amyloid-β (Aβ) oligomers (AβOs), which elicit neurotoxicity and synaptotoxicity, are thought to play an initiating role in the pathology of Alzheimer's disease (AD). Since AβOs are a key therapeutic target, we attempted to identify natural agents that reduce AβO neurotoxicity. Using an assay system in which primary cultured neurons are treated with AβOs, we found that Rhodiola rosea extracts and one of its main constituents, tyrosol, significantly inhibited AβO-induced caspase-3 activation. We then assessed the in vivo efficacy of tyrosol by oral administration of the compound into AD model (5XFAD) transgenic and non-transgenic mice from either 2 or 4 to 7 months of age. In both paradigms, tyrosol treatment did not affect body weights of mice. Immunohistochemical analysis revealed that the immunoreactivity of spinophilin, a dendritic synaptic protein, was significantly reduced in three hippocampal subregions of vehicle-treated AD mice compared with non-transgenic mice, which was reversed in tyrosol-treated AD mice. Tyrosol treatment also prevented the enhancement of 4-hydroxy-2-nonenal immunoreactivity in the hippocampal CA3 region of AD mice. By contrast, tyrosol administration did not affect Aβ accumulation, as evaluated by immunohistochemical and biochemical analyses. Moreover, the Barnes maze test showed that tyrosol administration modestly mitigated spatial memory impairment in AD mice. These findings collectively indicate that the natural agent tyrosol protects neurons against AβO neurotoxicity in vitro and ameliorates synaptic disturbance, oxidative stress responses, and cognitive impairment in vivo. We thus suggest that tyrosol is potentially an effective, safe, and unique drug candidate for AD.

Gastrodigenin rhamnopyranoside (GR) is a hepatoprotective compound that exists in Moringa oleifera seeds. However, the UPLC-MS/MS method for the determination of GR (in-vitro/in-vivo) is lacking clarification. Herein, this study established the UPLC-MS/MS technique, which was effective and sensitive for the investigation of the pharmacokinetics and biodistribution of GR in rats and mice. The separation was achieved with a Shim-pack XR-ODS III C₁₈ column (2.0 × 75 mm, 1.6 μm) at 40 °C, while the mobile phase (Acetonitrile/0.1% Formic acid =12:82, v/v) was at an eluting rate of 0.2 mL/min. The Multiple Reaction Monitoring (MRM) was selected for quantification, i.e., m/z [M + HCOO]^- 314.9 → 269 for GR and m/z [M + HCOO] ^- 182.85 → 137 for Tyrosol as the internal standard. The calibration curves were linearly ranged from 10 to 2500 ng/mL (r ≥ 0.999) with a lower-limit-of-quantification (LLOQ) of 10 ng/mL in the various biological samples (plasma, liver, heart, lung, spleen, brain, kidney). The intra- and inter-day precision was within 5%, while accuracy ranged from -11.4% - 8.33%. Recovery and matrix effect were with 80.32 to 101.31% and 90.36 to 103.76%, respectively, in a reasonable range. After oral and intravenous administration, GR was detected within 3 h but decreased rapidly in plasma, indicating fast elimination. Also, GR was quickly distributed in the various tissues, particularly in the kidney and spleen. The results demonstrated that the established UPLC-MS/MS method was highly linear, precise and accurate with the potential to be used for the quantitative analysis of GR in-vivo.

Sulfated phenolic polymers have extensively been investigated as anticoagulant agents in view of their higher bioavailability and resistance to degradation compared to heparins, allowing for increased half-lives. In this frame, we report herein the preparation of sulfated derivatives of tyrosol, one of the most representative phenolic constituents of extra virgin olive oil, by different approaches. Mild sulfation of OligoTyr, a mixture of tyrosol oligomers, that has been reported to possess antioxidant properties and osteogenic activity, afforded OligoTyrS I in good yields. Elemental analysis, NMR, and MALDI-MS investigation provided evidence for an almost complete sulfation at the OH on the phenylethyl chain, leaving the phenolic OH free. Peroxidase/H₂O₂ oxidation of tyrosol sulfated at the alcoholic group (TyrS) also provided sulfated tyrosol oligomers (OligoTyrS II) that showed on structural analysis highly varied structural features arising likely from the addition of oxygen, derived from water or hydrogen peroxide, to the intermediate quinone methides and substantial involvement of the phenolic OH group in the oligomerization. In line with these characteristics, OligoTyrS I proved to be more active than OligoTyrS II as antioxidant in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays and as anticoagulant in the classical clotting times, mainly in prolonging the activated partial thromboplastin time (APTT). After intraperitoneal administration in mice, OligoTyrS I was also able to significantly decrease the weight of an induced thrombus. Data from chromogenic coagulation assays showed that the anticoagulant effect of OligoTyrS I was not dependent on antithrombin or factor Xa and thrombin direct inhibition. These results clearly highlight how some structural facets of even closely related phenol polymers may be critical in dictating the anticoagulant activity, providing the key for the rationale design of active synthetic nonsaccharidic anticoagulant agents alternative to heparin.

In the present work, a rapid, accurate and cost-effective method has been developed for the simultaneous quantification of phenolic compounds in oil using mixed-mode solid-phase extraction (SPE) coupled with chemical labeling UHPLC-MS/MS. Mix-mode SPE weak cation cartridges were selected to enrich and purify phenolic compounds in oil, and hydroxyl moiety was dansylation as stable-isotope internal standard. The major parameters that affected the extraction and chemical labeling efficiency were investigated, and the method was fully validated. The limit of quantifications and the limit of detections were 0.002 µg kg^-1 ~ 0.10 µg kg^-1 and 0.006 µg kg^-1 ~ 0.30 µg kg^-1, respectively. The recoveries were 61.2% ~ 129.3% with intra-day and inter-day precision less than 12%. The results for 38 rapeseed oils revealed that 14 phenolic compounds, including canolol, phenolic acids, phenolic alcohols, tyrosol and vanillin from trace levels to relatively high content.

Keywords: Chemical labeling; Mixed-mode solid-phase extraction (SPE); Phenolic compounds; Quantification; Rapeseed oil; Ultra-performance liquid chromatography-mass spectrometry (UHPLC-MS/MS).