Yield and Composition of the Essential Oil of Clinopodium nepeta subsp. spruneri as Affected by Harvest Season and Cultivation Method, i.e., Outdoor, Greenhouse and In Vitro Culture.

Clinopodium nepeta subsp. spruneri is an aromatic herb with a mint-oregano flavor, used in Mediterranean regions in traditional medicine. The aerial parts of the plant are rich in essential oil that has antioxidant, antimicrobial and anti-inflammatory properties as well as insecticidal activity. The aim of our work was to determine the yield and composition of the essential oil of the plant, in relation to the harvest season and cultivation method, i.e., outdoor, greenhouse and in vitro culture, using gas chromatography-mass spectrometry (GC-MS) as an analytical tool. Essential oil yield fluctuated similarly in outdoor and greenhouse plants during the year (0.9-2.6%), with higher percentages (2.1-2.6%) in the hottest periods June-October (flowering stage) and April (vegetative stage), and was similar to the yield in in vitro plants (1.7%). More compounds were identified in the oil of outdoor and greenhouse plants (35) compared to that of in vitro plants (21), while the main compounds were the same, i.e., pulegone (13.0-32.0%, highest in February-April, 15.0% in vitro), piperitenone oxide (3.8-31.8%, lowest in February, 34.2% in vitro), piperitone epoxide (4.6-16.4%, highest in February, 15.5% in vitro), D-limonene (2.1-8.8%, lowest in February, 10.0% in vitro), isomenthone (2.3-23.0%, highest in February, 4.6% in vitro), germacrene D (1.9-6.5% highest in December-April, 2.9% in vitro) and dicyclogermacrene (2.1-5.3%, highest in December-April, 5.2% in vitro). Therefore, greenhouse and in vitro cultures were equally efficient in yielding essential oil and its constituents as outdoor cultivation, while in outdoor and greenhouse cultivations, the harvest season, mainly due to the prevailing ambient temperatures, affected the essential oil yield and its percentage composition.

Chemical Composition of the Essential Oils of Three Popular Sideritis Species Cultivated in Greece Using GC-MS Analysis.

(1) Background: The essential oils (EOs) of Sideritis L. have attracted great interest due to their pharmacological activities and potential applications in the cosmetic and perfume industries. The aim of this work was to study the EO chemical composition of three of the most popular, in Greece, mountain tea species: namely, these include Sideritis scardica, Sideritis raeseri, and Sideritis syriaca. (2) Methods: The EOs were obtained from the aerial parts of three Sideritis species that were cultivated in various regions of Greece by hydrodistillation, and the chemical composition was studied by gas chromatography-mass spectrometry (GC-MS) analysis. (3) Results: The EOs of the Sideritis species-S. scardica (SSC1, SSC2, SSC3), S. raeseri (SR1, SR2, SR3), and S. syriaca (SS1, SS2, SS3)-were analyzed by GC-MS, and they showed both qualitatively and quantitatively high variation in their chemical composition. (4) Conclusions: The EOs of S. scardica and S. raeseri from three different regions of Greece, and the S. syriaca from three different localities of Crete Island in Southern Greece, showed high chemical variability. Although 165 different components were found to be present in the nine samples through GC-MS analysis, only 7 (1-octen-3-ol, linalool, trans-pinocarveol, p-mentha-1,5-dien-8-ol, α-terpineol, myrtenol, and verbenone) were common components in the nine EOs, which were identified to be highly variable in different percentages among the samples. Even the EOs of SS1 and SS2, which were cultivated nearby, showed different GC profiles. The composition variation observed might be attributed to differentiations in the soil and climatic conditions.

Determining the Nutrient Content of Hydroponically-Cultivated Microgreens with Immersible Silicon Photonic Sensors: A Preliminary Feasibility Study.

Microgreens have gained attention for their exceptional culinary characteristics and high nutritional value. The present study focused on a novel approach for investigating the easy extraction of plant samples and the utilization of immersible silicon photonic sensors to determine, on the spot, the nutrient content of microgreens and their optimum time of harvest. For the first time, it was examined how these novel sensors can capture time-shifting spectra caused by the molecules' dynamic adhesion onto the sensor surface. The experiment involved four types of microgreens (three types of basil and broccoli) grown in a do-it-yourself hydroponic installation. The sensors successfully distinguished between different plant types, showcasing their discriminative capabilities. To determine the optimum harvest time, this study compared the sensor data with results obtained through standard analytical methods. Specifically, the total phenolic content and antioxidant activity of two basil varieties were juxtaposed with the sensor data, and this study concluded that the ideal harvest time for basil microgreens was 14 days after planting. This finding highlights the potential of the immersible silicon photonic sensors for potentially replacing time-consuming analytical techniques. By concentrating on obtaining plant extracts, capturing time-shifting spectra, and assessing sensor reusability, this research paves the way for future advancements in urban farming.

Studying the metabolic factors that may impact the growth of co-cultured Listeria monocytogenes strains at low temperature.

The simultaneous presence of more than one strains of Listeria monocytogenes in the same food product may affect the growth capacity of each strain. The present study evaluated the metabolites composition that may potentially influence the growth of individual L. monocytogenes strains in a dual strain composite. Based on previous studies, L. monocytogenes strains, C5 (4b) and 6179 (1/2a) were selected due to the remarkable interaction, which was observed during their co-culture. The selected strains were inoculated (2.0 - 3.0 log CFU/mL) in Tryptic Soy Broth with 0.6% Yeast Extract (TSB-YE) in single and two-strain cultures (1:1 strain ratio). Bacterial growth was assessed during storage at 7 °C, under aerobic conditions (AC). Their resistance to different antibiotics enabled the selective enumeration of each strain in the co-culture. After reaching stationary phase, single and dual cultures were centrifuged and filtered. The cell-free spent medium (CFSM) was either characterized by Fourier transform infrared (FTIR-ATR) spectrometry or re-inoculated, after the addition of concentrated TSB-YE (for nutrient replenishment), with single and two-strain cultures for the evaluation of growth under the influence of metabolites produced from the same singly and co-cultured strains in the different combinations of strains and CFSM origin (7 °C/AC) (n = 2x3). By the end of storage, singly-cultured C5 and 6179 had reached 9.1 log CFU/mL, while in dual culture, 6179 was affected by the presence of C5 attaining only 6.4 ± 0.8 log CFU/mL. FTIR-ATR spectra of CFSM produced by singly-cultured 6179 and the co-culture were almost identical. Characteristic peaks in FTIR-ATR spectrum of CFSM of singly-cultured C5 at 1741, 1645 and 1223 cm-1 represent functional groups which were not present in the CFSM of the co-culture. These molecules may be located intracellularly or mounted on bacterial cell surface and removed from the supernatant during cell filtration of the co-culture. Both singly- and co-cultured 6179 managed to grow similarly regardless of CFSM origin. Contrarily, both singly- and co-cultured C5 managed to outgrow 6179 in CFSM which contained high concentration of C5 metabolites, while in CFSM produced by singly-cultured 6179, C5 did not grow, suggesting that the produced metabolites of strain 6179 appears to be harmful to strain C5. However, during co-culture, C5 may produce molecules that counteract the inhibitory effect of 6179. The findings shed more light on the mechanism behind the inter-strain interactions of L. monocytogenes indicating that both contact of cells and extracellular metabolites may influence the behavior of the different co-existing strains.

Chemical Characterization and Antioxidant Activity of Nine Hypericum Species from Greece.

Hypericum L. comprises about 500 species distributed almost worldwide. Research has mainly focused on H. perforatum with confirmed biological activity on the alleviation of depression symptoms, among others. The compounds responsible for such activity are considered naphthodianthrones and acylphloroglucinols. Other Hypericum species are less studied or not studied, and further research is needed to complete the characterization of the genus. In this study we evaluated the qualitative and quantitative phytochemical profile of nine Hypericum species native to Greece, namely H. perforatum, H. tetrapterum, H. perfoliatum, H. rumeliacum subsp. apollinis, H. vesiculosum, H. cycladicum, H. fragile, H. olympicum and H. delphicum. Qualitative analysis was performed using the LC/Q-TOF/HRMS technique, while quantitative data were calculated with the single point external standard method. Additionally, we estimated the antioxidant activity of the extracts using DPPH and ABTS assays. Three species endemic to Greece (H. cycladicum, H. fragile, H. delphicum) were studied for the first time. Our results indicated that all studied species are rich in secondary metabolites, mainly of the flavonoids family, with strong antioxidant activity.

Origanum majorana Essential Oil-A Review of Its Chemical Profile and Pesticide Activity.

Origanum majorana is a medicinal and aromatic plant that belongs to the Lamiaceae family. It is cultivated in several parts of the world and, due to its splendid aroma and taste, is widely used for culinary purposes and in perfumes. The essential oil of the plant, to which is attributed its aroma, contains many secondary metabolites with valuable biological activity. One of them is the pesticide activity, which has attracted much interest. Given the necessity of replacing synthetic pesticides, essential oils are studied in an attempt to find naturally derived products. Thus, the aim of this review paper is to discuss the chemical profile of O. majorana essential oil and to present data regarding its insecticidal, repellent and fumigant activity. Data were collected from 1992 to 2022. Databases, including PubMed, Google Scholar, ScienceDirect and Scopus, were used for the research, and keywords, including O. majorana, sweet marjoram, essential oil, volatiles, pesticide, insecticide and repellent activity, were used. The results of this review paper indicate that O. majorana essential oil can be an alternative agent to manage pests. However, still, much research should be conducted to evaluate its toxicity against beneficial insects and to ensure its safety for human health.

Cytotoxic Effect of Rosmarinus officinalis Extract on Glioblastoma and Rhabdomyosarcoma Cell Lines.

Rosmarinus officinalis is a well-studied plant, known for its therapeutic properties. However, its biological activity against several diseases is not known in detail. The aim of this study is to present new data regarding the cytotoxic activity of a hydroethanolic extract of Rosmarinus officinalis on glioblastoma (A172) and rhabdomyosarcoma (TE671) cancer cell lines. The chemical composition of the extract is evaluated using liquid chromatography combined with time-of-flight mass spectrometry, alongside its total phenolic content and antioxidant activity. The extract showed a promising time- and dose-dependent cytotoxic activity against both cell lines. The lowest IC50 values for both cell lines were calculated at 72 h after treatment and correspond to 0.249 ± 1.09 mg/mL for TE671 cell line and 0.577 ± 0.98 mg/mL for A172 cell line. The extract presented high phenolic content, equal to 35.65 ± 0.03 mg GAE/g of dry material as well as a strong antioxidant activity. The IC50 values for the antioxidant assays were estimated at 12.8 ± 2.7 µg/mL (DPPH assay) and 6.98 ± 1.9 µg/mL (ABTS assay). The compound detected in abundance was carnosol, a phenolic diterpene, followed by the polyphenol rosmarinic acid, while the presence of phenolic compounds such as rhamnetin glucoside, hesperidin, cirsimaritin was notable. These preliminary results suggest that R. officinalis is a potential, alternative source of bioactive compounds to further examine for abilities against glioblastoma and rhabdomyosarcoma.

An In Vitro Study of Saffron Carotenoids: The Effect of Crocin Extracts and Dimethylcrocetin on Cancer Cell Lines.

Crocus sativus L. has various pharmacological properties, known for over 3600 years. These properties are attributed mainly to biologically active substances, which belong to the terpenoid group and include crocins, picrocrocin and safranal. The aim of the current work was to examine the effects of crocins (CRCs) and their methyl ester derivate dimethylcrocetin (DMCRT) on glioblastoma and rhabdomyosarcoma cell lines, in terms of cytotoxicity and gene expression, implicated in proapoptotic and cell survival pathways. Cell cytotoxicity was assessed with Alamar Blue fluorescence assay after treatment with saffron carotenoids for 24, 48 and 72 h and concentrations ranging from 22.85 to 0.18 mg/mL for CRCs and 11.43 to 0.09 mg/mL for DMCRT. In addition, BAX, BID, BCL2, MYCN, SOD1, and GSTM1 gene expression was studied by qRT-PCR analysis. Both compounds demonstrated cytotoxic effects against glioblastoma and rhabdomyosarcoma cell lines, in a dose- and time-dependent manner. They induced apoptosis, via BAX and BID upregulation, MYCN and BCL-2, SOD1, GSTM1 downregulation. The current research denotes the possible anticancer properties of saffron carotenoids, which are considered safe phytochemicals, already tested in clinical trials for their health promoting properties.

Chemical Characterization, Antioxidant and Antimicrobial Properties of Different Types of Tissue of Cedrus brevifolia Henry Extracts.

This study aimed to determine the chemical composition of different types of tissue of Cedrus brevifolia Henry (Pinaceae) methanolic extracts, namely needles, twigs, branches, and bark. Cedrus brevifolia is a narrow endemic coniferous tree species of Cyprus, growing in a sole population in the mountainous area of Paphos Forest. Chemical analysis of the extracts was performed using liquid chromatography combined with time-of-flight high-resolution mass spectrometry (LC/Q-TOF/HRMS). The majority of the 36 compounds tentatively identified belonged to the flavonoids family. The extract of needles was the richest extract in terms of secondary metabolites. The extracts were studied for their antioxidant activity using the DPPH free radical scavenging assay. Additionally, the antibacterial activity was evaluated by determining both the minimum inhibitory concentration and the minimum bactericidal concentration against Staphylococcus aureus and Escherichia coli. All extracts demonstrated antioxidant property, while bark gave the highest antioxidant capacity (IC50 value of 0.011 mg/mL) compared to the other tissues. Antibacterial activity was observed against both types of bacteria, with the extract of branches presenting the strongest activity against S. aureus (MIC, 0.097 mg/mL and MBC, 0.195 mg/mL). This is the first time that extracts of needles, twigs, branches, and bark of C. brevifolia are compared regarding their chemical composition as well as their antimicrobial and antioxidant properties.

The application of right-angle fluorescence spectroscopy as a tool to distinguish five autochthonous commercial Greek white wines.

White wine is among the most widely consumed alcoholic beverages. Varietal discrimination of wines has received increasing attention. Today's consumers require a sense of authenticity and are deterred by falsehood or misrepresentation in product marketing. However, wine can involve various types of frauds, which directly affects the distribution of wine in national and international markets. Right-angle fluorescence spectroscopy is a simple and rapid analytical technique that in combination with chemometric algorithms, constitutes a novel method for wine authentication. In this study, the stepwise-Linear Discriminant Analysis algorithm was applied in three representative spectral regions related to phenolic compounds for the purpose of distinguishing white wines according to the grape variety. The wavelength at 310 nm attributed to the hydroxycinnamic acids and stilbene provided a higher classification rate (95.5%) than the λex 280 and 295 nm regions (79.8%), suggesting that these compounds are highly related to the botanical origin of samples. The chemometric models were validated utilizing cross-validation and an external validation set to enhance the robustness of the proposed methodology. The above-mentioned methodology constitutes a powerful tool for the varietal discrimination of white wines and can be used in industrial setting. The ultimate goal of this study is to contribute to the efforts towards the authentication of Greek white wine which will eventually support producers and suppliers to remain competitive and simultaneously protect the consumers from fraudulent practices.

Unifloral Autumn Heather Honey from Indigenous Greek Erica manipuliflora Salisb.: SPME/GC-MS Characterization of the Volatile Fraction and Optimization of the Isolation Parameters.

For long heather honey has been a special variety due to its unique organoleptic characteristics. This study aimed to characterize and optimize the isolation of the dominant volatile fraction of Greek autumn heather honey using solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The described approach pointed out 13 main volatile components more closely related to honey botanical origin, in terms of occurrence and relative abundance. These volatiles include phenolic compounds and norisoprenoids, with benzaldehyde, safranal and p-anisaldehyde present in higher amounts, while ethyl 4-methoxybenzoate is reported for the first time in honey. Then, an experimental design was developed based on five numeric factors and one categorical factor and evaluated the optimum conditions (temperature: 60 °C, equilibration time: 30 min extraction time: 15 min magnetic stirrer velocity: 100 rpm sample volume: 6 mL water: honey ratio: 1:3 (v/w)). Additionally, a validation test set reinforces the above methodology investigation. Honey is very complex and variable with respect to its volatile components given the high diversity of the floral source. As a result, customizing the isolation parameters for each honey is a good approach for streamlining the isolation volatile compounds. This study could provide a good basis for future recognition of monofloral autumn heather honey.

Authentication of the Botanical and Geographical Origin and Detection of Adulteration of Olive Oil Using Gas Chromatography, Infrared and Raman Spectroscopy Techniques: A Review.

Olive oil is among the most popular supplements of the Mediterranean diet due to its high nutritional value. However, at the same time, because of economical purposes, it is also one of the products most subjected to adulteration. As a result, authenticity is an important issue of concern among authorities. Many analytical techniques, able to detect adulteration of olive oil, to identify its geographical and botanical origin and consequently guarantee its quality and authenticity, have been developed. This review paper discusses the use of infrared and Raman spectroscopy as candidate tools to examine the authenticity of olive oils. It also considers the volatile fraction as a marker to distinguish between different varieties and adulterated olive oils, using SPME combined with gas chromatography technique.

Response Surface Methodology to Optimize the Isolation of Dominant Volatile Compounds from Monofloral Greek Thyme Honey Using SPME-GC-MS.

This study aimed at an experimental design of response surface methodology (RSM) in the optimization of the dominant volatile fraction of Greek thyme honey using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). For this purpose, a multiple response optimization was employed using desirability functions, which demand a search for optimal conditions for a set of responses simultaneously. A test set of eighty thyme honey samples were analyzed under the optimum conditions for validation of the proposed model. The optimized combination of isolation conditions was the temperature (60 °C), equilibration time (15 min), extraction time (30 min), magnetic stirrer speed (700 rpm), sample volume (6 mL), water: honey ratio (1:3 v/w) with total desirability over 0.50. It was found that the magnetic stirrer speed, which has not been evaluated before, had a positive effect, especially in combination with other factors. The above-developed methodology proved to be effective in the optimization of isolation of specific volatile compounds from a difficult matrix, like honey. This study could be a good basis for the development of novel RSM for other monofloral honey samples.

Chemometric Study of Fatty Acid Composition of Virgin Olive Oil from Four Widespread Greek Cultivars.

Virgin olive oil (VOO) is one of the key components of the Mediterranean diet owing to the presence of monounsaturated fatty acids and various bioactive compounds. These beneficial traits, which are usually associated with the cultivar genotype, are highlighting the demand of identifying characteristics of olive oil that will ensure its authenticity. In this work, the fatty acid (FA) composition of 199 VOO samples from Koroneiki, Megaritiki, Amfissis, and Manaki cultivars was determined and studied by chemometrics. Olive cultivar greatly influenced the FA composition, namely, oleic acid (from 75.36% for Amfissis to 65.81% for Megaritiki) and linoleic acid (from 13.35% for Manaki to 6.70% for Koroneiki). Spearman's rho correlation coefficients revealed differences and similarities among the olive oil cultivars. The use of the forward stepwise algorithm identified the FAs arachidonic acid, gadoleic acid, linoleic acid, α-linolenic acid, palmitoleic acid, and palmitic acid as the most significant for the differentiation of samples. The application of linear and quadratic cross-validation discriminant analysis resulted in the correct classification of 100.00% and 99.37% of samples, respectively. The findings demonstrated the special characteristics of the VOO samples derived from the four cultivars and their successful botanical differentiation based on FA composition.

Nutraceuticals-based therapeutic approach: recent advances to combat pathogenesis of Alzheimer's disease.

Introduction: Alzheimer's disease (AD) is a progressive neurodegenerative disease accompanying memory deficits. The available pharmaceutical care has some limitations mostly entailing side effects, shelf-life, and patient's compliance. The momentous implications of nutraceuticals in AD have attracted scientists. Several preclinical studies for the investigation of nutraceuticals have been conducted.Areas covered: This review focuses on the potential use of a nutraceuticals-based therapeutic approach to treat and prevent AD. Increasing knowledge of AD pathogenesis has led to the discovery of new therapeutic targets including pathophysiological mechanisms and various cascades. Hence, the present contribution will attend to the most popular and effective nutraceuticals with proposed brief mechanisms entailing antioxidant, anti-inflammatory, autophagy regulation, mitochondrial homeostasis, and more. Therefore, even though the effectiveness of nutraceuticals cannot be dismissed, it is essential to do further high-quality randomized clinical trials.Expert opinion: According to the potential of nutraceuticals to combat AD as multi-target directed drugs, there is critical importance to assess them as feasible lead compounds for drug discovery and development. To the best of the authors' knowledge, modification of blood-brain barrier permeability, bioavailability, and features of randomized clinical trials should be considered in prospective studies.

Crocins, the Bioactive Components of Crocus sativus L., Counteract the Disrupting Effects of Anesthetic Ketamine on Memory in Rats.

Consistent experimental evidence suggests that anesthetic doses of the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist ketamine cause severe memory impairments in rodents. Crocins are among the various bioactive ingredients of the plant Crocus sativus L., and their implication in memory is well-documented. It has not yet been elucidated if crocins are able to attenuate the memory deficits produced by anesthetic ketamine. The present study was undertaken aiming to clarify this issue in the rat. For this aim, the object recognition, the object location and the habituation tests, reflecting non-spatial recognition memory, spatial recognition memory and associative memory, respectively, were utilized. A post-training challenge with crocins (15-30 mg/kg, intraperitoneally (i.p.), acutely) counteracted anesthetic ketamine (100 mg/kg, i.p.)-induced performance impairments in all the above-mentioned behavioral memory paradigms. The current findings suggest that crocins modulate anesthetic ketamine's amnestic effects.

Rapid screening on aflatoxins' presence in Pistachia vera nuts using diffuse reflectance infrared Fourier transform spectroscopy and chemometrics.

Aflatoxin contamination in pistachios has been analyzed in this work, using Diffuse Reflectance Infrared Spectroscopy (DRIFTS) with chemometrics. Forty-nine Greek pistachio samples of different aflatoxin concentrations were classified into aflatoxin and non-aflatoxin groups using the 3035-2821, 1770-1721, 1570-1481 and 1260-1061 cm-1 spectral regions in Kubelka-Munk conversion and first derivative form. A chemometric model was developed using twenty-eight samples as calibration, 11 as validation and 10 as test set. The discrimination analysis separated correctly the 100% of the calibration and the validation set and the 80% of the test set. The proposed chemometric model is simple, rapid, economical and environmentally friendly since it does not require chemical pre-treatment of the samples. It is expected that the present method may be proved useful in food industry and the inspection authorities as a rapid decision-making tool to detect batches that must be rejected and enhance consumers' protection from aflatoxin contaminated pistachios.

Tantalizing role of p53 molecular pathways and its coherent medications in neurodegenerative diseases.

Neurodegenerative diseases are incongruous, commonly age-related disorders characterized by progressive neuronal loss, comprising the most prevalent being Alzheimer's disease, Parkinson's disease, and Huntington's disease. Perilous health states are anticipated following the neurodegeneration. Their etiology remains largely ambiguous, while various mechanisms are ascribed to their pathogenesis. A recommended conception is regarding the role of p53, as a transcription factor regulating numerous cellular pathways comprising apoptosis. Neuronal fates are a feasible occurrence that contributes to all neurodegenerative diseases. In this work, we review the research investigated the potential role of p53 in the pathogenesis of these diseases. We put special emphasis on intricate We not only describe aberrant changes in p53 level/activity observed in CNS regions affected by particular diseases but, most importantly, put special attention to the complicated reciprocal tuning connections prevailing between p53 and molecules considered in pathological hallmarks of these disorders. Natural and synthetic medications regulating p53 expression are regarded as well.

Quantitative determination of aloin, antioxidant activity, and toxicity of Aloe vera leaf gel products from Greece.

BACKGROUND: Aloe vera is a popular medicinal plant used widely by the cosmetic, pharmaceutical, and food industries. The A. vera leaf gel, which is used mostly for its positive effects on human health, contains over 75 different bioactive compounds, including aloin. Aloin is a toxic compound, and its content in A. vera leaf gel products depends on the different cultivation conditions and especially on leaf processing. RESULTS: In this study, A. vera leaf gel products, varied in terms of leaf processing, were analyzed using liquid chromatography for their aloin content, their antioxidant activity by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS·+ ) and the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH· ) antioxidant activity assays and their toxicity against Aliivibrio fisheri and SH-SY5Y cells. In the samples processed with industrial methods and in those filtered in the lab, the content of aloin was found below the limit (0.1 mg L-1 ) of the EU legislation however, the unprocessed and unfiltered samples were found to contain more than 10 mg L-1 . Antioxidant activity was estimated to vary from 1.64 to 9.21 µmol Trolox mL-1 for DPPH· and from 0.73 to 5.14 µmol Trolox mL-1 for ABTS·+ . Toxicity values on A. fisheri, expressed as the concentration at 50% loss of initial luminescence, ranged from 0.03 to 0.09 mg mL-1 . The cytotoxic study indicated that aloin A at low concentrations (1 and 10 µg mL-1 ) protects SH-SY5Y cells from toxicity induced by hydrogen peroxide. CONCLUSIONS: Consequently, the filtration process of A. vera leaf gels, either laboratory or industrial, resulted in aloin A content below the EU legislation detection limits. © 2020 Society of Chemical Industry.

Discrimination of botanical origin of olive oil from selected Greek cultivars by SPME-GC-MS and ATR-FTIR spectroscopy combined with chemometrics.

BACKGROUND: Consumers today wish to know the botanical origin of the olive oil they purchase. The objective of the present study was the development of robust chemometric models based on gas chromatography-mass spectrometry (GC-MS) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for the purpose of botanical differentiation of three commercial Greek olive oil cultivars. RESULTS: Using the solid-phase microextraction technique (SPME), volatile compounds (VC) were obtained and analyzed by GC-MS. Five hydrocarbons and one ester were selected by the forward stepwise algorithm, which best discriminated the olive oil samples. From ATR-FTIR analysis, the spectral regions chosen from the forward stepwise algorithm were associated with CO stretching vibration of the esters of triglycerides and the CH bending vibrations of the CH2 aliphatic group and double bonds. Application of the supervised methods of linear and quadratic discriminant cross-validation analysis, based on VC data, provided a correct classification score of 97.4% and 100.0%, respectively. Corresponding statistical analyses were used in the mid-infrared spectra, by which 96.1% of samples were discriminated correctly. CONCLUSION: ATR-FTIR and SPME-GC-MS techniques in conjunction with the appropriate feature selection algorithm and classification methods proved to be powerful tools for the authentication of Greek olive oil. The proposed methodology could be used in an industrial setting for determination of the botanical origin of Greek olive oil. © 2020 Society of Chemical Industry.