Availability and Metabolic Fate of Olive Phenolic Alcohols Hydroxytyrosol and Tyrosol in the Human GI Tract Simulated by the In Vitro GIDM-Colon Model.

Hydroxytyrosol (HTyr) and tyrosol (Tyr) are the most well studied phenolic alcohols of olive oil and olive products demonstrating numerous and significant beneficial health effects. However, their activity in the human organism as food bioactives is strongly associated with their bioavailability and metabolism, while manifested through their metabolites. Nevertheless, there are limited studies investigating their biotransformation and mainly catabolism by gut microflora under a holistic interpretation close to the human organism. Thus, in the present study, the GastroIntestinal Dialysis (GIDM)-colon model, a continuous flow in vitro dialysis system mimicking physiological conditions during human gastrointestinal digestion, was used to explore the metabolism of HTyr and Tyr as pure compounds. The GIDM-colon model simulates absorption from the lumen to the mucosa, followed by the colon phase using pooled human fecal suspensions. Samples were collected at different time points and analyzed via LC-Orbitrap MS. An integrated approach combining Multivariate Data Analysis (MVA) and thorough dereplication procedures led to the identification of HTyr and Tyr metabolites in different phases (gastric, small intestine, and colon), yielding also valuable information about metabolites kinetics. To our knowledge, this is the first study reporting full spectrometric data of HTyr and Tyr metabolites along with possible transformation mechanisms in the GI tract.

Structure and organization of the secretion apparatus of the mastic tree (Pistacia lentiscus L.) and LC-HRMS analysis of leaf extracts.

MAIN CONCLUSION: The quantitative profile of the biochemicals secreted by summer and winter leaves, present noticeable differences and appear to be qualitatively different from the biochemical profile of the commercially valuable mastic. The anatomy of the root and the primary and secondary shoot as well as that of the summer and winter leaves of P. lentiscus was thoroughly investigated. The secreting network was tracked throughout the plant axis, from the root to the leaves, and the active secreting cells of the duct epithelium were localized, while the secondary metabolites produced within the cells of the summer and winter leaf tissues were identified histochemically. Numerous phytochemicals were identified in the leaf extracts with UHPLC-qTOF MS analysis. The analyzed extracts from summer and winter leaves displayed similar qualitative profile, although quantitative differences were evident, since, during the summer, the leaves tend to synthesize the more complex amongst the identified compounds. The phytochemical profile of the leaf extracts turns to be completely different compared to that of the valuable mastic harvested from the injured trunks. Many of the compounds common in mastic were not detected in the analyzed leaves samples. The numerous secreting ducts either fail to form a unified network, so composition of the secreted material varies in the different organs of the plant or they compose a continuous network, but the biochemical profile of the secreted material differs along the plant axis. Such a detailed investigation of the secretion network of the mastic tree may assist the improvement of the yield and promote the production of valuable phytochemicals through in vitro cultures.

Isotopic Traceability (13C and 18O) of Greek Olive Oil.

In recent years, isotopic analysis has been proven a valuable tool for the determination of the origin of various materials. In this article, we studied the 18O and 13C isotopic values of 210 olive oil samples that were originated from different regions in Greece in order to verify how these values are affected by the climate regime. We observed that the δ18O isotopic values range from 19.2 ‱ to 25.2 ‱ and the δ13C values range from -32.7 ‱ to -28.3 ‱. These differences between the olive oils' isotopic values depended on the regional temperature, the meteoric water, and the distance from the sea. Furthermore, we studied the 13C isotopic values of biophenolic extracts, and we observed that they have same capability to differentiate the geographic origin. Finally, we compared the isotopic values of Greek olive oils with samples from Italy, and we concluded that there is a great dependence of oxygen isotopes on the climatic characteristics of the different geographical areas.

Olive Oil Quality and Authenticity Assessment Aspects Employing FIA-MRMS and LC-Orbitrap MS Metabolomic Approaches.

Edible vegetable oils comprise integral components of humans' daily diet during the lifetime. Therefore, they constitute a central part of dietary-exposome, which among other factors regulates human health. In particular, the regular consumption of olive oil (OO) has been largely accepted as a healthy dietary pattern. Responsible for its recognition as a superior edible oil is its exceptional aroma and flavor. Its unique composition is characterized by high levels of monounsaturated fatty acids and the presence of minor constituents with important biological properties, such as the so-called OO polyphenols. Being a high added value product, OO suffers from extensive fraud and adulteration phenomena. However, its great chemical complexity, variability, and the plethora of parameters affecting OO composition hamper significantly the selection of the absolute criteria defining quality and authenticity, and a reliable and robust methodology is still unavailable. In the current study, Flow Injection Analysis-Magnetic Resonance Mass Spectrometry (FIA-MRMS) was investigated under a metabolic profiling concept for the analysis of Greek Extra Virgin Olive Oils (EVOO). More than 200 monovarietal (Koroneiki) EVOO samples were collected from the main Greek OO producing regions and investigated. Both intact oil and the corresponding polyphenols were analyzed in fast analysis time of 2 and 8 min, respectively. In parallel, an LC-Orbitrap MS platform was used to verify the efficiency of the method as well as a tool to increase the identification confidence of the proposed markers. Based on the results, with FIA-MRMS, comparable and improved projection and prediction models were generated in comparison to those of the more established LC-MS methodology. With FIA-MRMS more statistically significant compounds and chemical classes were identified as quality and authenticity markers, associated with specific parameters, i.e. geographical region, cultivation practice, and production procedure. Furthermore, it was possible to monitor both lipophilic and hydrophilic compounds with a single analysis. To our knowledge, this approach is among the few studies in which two FT-MS platforms combining LC and FIA methods were integrated to provide solutions to quality control aspects of OO. Moreover, both lipophilic and hydrophilic components are analyzed together, providing a holistic quality control workflow for OO.

UPLC-MS/MS-based molecular networking and NMR structural determination for the untargeted phytochemical characterization of the fruit of Crescentia cujete (Bignoniaceae).

The fruit pulp of Crescentia cujete is traditionally used in folk medicine for the treatment of a variety of respiratory conditions and gastrointestinal disorders. Due to the lack of a comprehensive phytochemical description of the fruit of this plant, its active compounds and rational quality control parameters have not yet been described. An untargeted metabolomics approach combining UPLC-MS/MS-based molecular networking with conventional isolation and NMR methods was carried out for the phytochemical profiling of the fruit pulp of Crescentia cujete. Sixty-six metabolites, including nine n-alkyl glycosides, twenty-three phenolic acid derivatives (such as cinnamoyl and benzoyl derivatives), fifteen flavonoids, four phenylethanoid derivatives and fifteen iridoid glycosides were identified at different levels of confirmation: eighteen confirmed structures (Level 1), six probable structures (Level 2) and forty two tentative candidates (Level 3). Among these, all four phenylethanoid derivatives were described for the first time within this species. In addition, 8-epi-eranthemoside, crescentiol A and crescentiol B were reported as three undescribed iridoid glucosides. The use of molecular networking has resulted in a detailed phytochemical overview of this species. This work provides a useful tool for further development and validation of appropriate analytical methods for routine quality control assessment of commercially available products containing the fruit of this species and further interpretation of their related pharmacological effects.

Selective cytotoxicity of the herbal substance acteoside against tumor cells and its mechanistic insights.

Natural products are characterized by extreme structural diversity and thus they offer a unique source for the identification of novel anti-tumor agents. Herein, we report that the herbal substance acteoside being isolated by advanced phytochemical methods from Lippia citriodora leaves showed enhanced cytotoxicity against metastatic tumor cells; acted in synergy with various cytotoxic agents and it sensitized chemoresistant cancer cells. Acteoside was not toxic in physiological cellular contexts, while it increased oxidative load, affected the activity of proteostatic modules and suppressed matrix metalloproteinases in tumor cell lines. Intraperitoneal or oral (via drinking water) administration of acteoside in a melanoma mouse model upregulated antioxidant responses in the tumors; yet, only intraperitoneal delivery suppressed tumor growth and induced anti-tumor-reactive immune responses. Mass-spectrometry identification/quantitation analyses revealed that intraperitoneal delivery of acteoside resulted in significantly higher, vs. oral administration, concentration of the compound in the plasma and tumors of treated mice, suggesting that its in vivo anti-tumor effect depends on the route of administration and the achieved concentration in the tumor. Finally, molecular modeling studies and enzymatic activity assays showed that acteoside inhibits protein kinase C. Conclusively, acteoside holds promise as a chemical scaffold for the development of novel anti-tumor agents.