Comparative elucidation of phenolic compounds in Albanian olive oils using LC-DAD-ESI-MS/MS

Abstract

Olive oils may provide health benefits, including the prevention of coronary heart diseases, cancers, and the modification of immune and inflammatory responses. These benefits mainly originate from the phenolic compounds found in olive oil. There has been no study on the advanced characterization of Albanian olive oils from various cultivars regarding phenolic compounds. Hence, a comprehensive characterization of phenolic compounds is carried out in Albanian monocultivar virgin olive oils from five different cultivars, including Kalinjot, Bardhi Tirana, Ulliri-i-Zi Tirana, Krips Kruja, and Bardhi Kruja for the first time. Liquid chromatography coupled to diode array detection and electrospray ?onization tandem mass spectrometry (LC-DAD-ESI-MS/MS) is employed for the determination of phenolic compounds. In total, 18 compounds were identified in all samples, including phenolic alcohols, phenolic acids, secoiridoids, flavonoids, and phenolic aldehydes. Significant quantitative differences were detected among the cultivars, with the highest concentrations detected in virgin olive oil (VOO) from cv. Ulli-i-Zi. Secoiridoids were found in abundance, in general, followed by phenolic alcohols, and in this group, 3,4-DHPEA-EDA and p-HPEA-EDA stood out as dominant compounds, especially in Kalinjot virgin olive oils. Regarding phenolic alcohols, 3,4-DHPEA-AC was determined as the main phenolic compound. Phenolic profiles were found to be significantly different among the olive oil samples of different cultivars. Principal component analyses (PCA) displayed the differentiation of samples in terms of phenolic compounds.     

Gas chromatography-atmospheric pressure chemical ionization-time of flight mass spectrometry for profiling of phenolic compounds in extra virgin olive oil

A new analytical approach based on gas chromatography coupled to atmospheric pressure chemical ionization-time of flight mass spectrometry was evaluated for its applicability for the analysis of phenolic compounds from extra-virgin olive oil. Both chromatographic and MS parameters were optimized in order to improve the sensitivity and to maximize the number of phenolic compounds detected. We performed a complete analytical validation of the method with respect to its linearity, sensitivity, precision, accuracy and possible matrix effects. The LODs ranged from 0.13 to 1.05ppm for the different tested compounds depending on their properties. The RSDs for repeatability test did not exceed 6.07% and the accuracy ranged from 95.4% to 101.5%. To demonstrate the feasibility of our method for analysis of real samples, we analyzed the extracts of three different commercial extra-virgin olive oils. We have identified unequivocally a number of phenolic compounds and obtained quantitative information for 21 of them. In general, our results show that GC-APCI-TOF MS is a flexible platform which can be considered as an interesting tool for screening, structural assignment and quantitative determination of phenolic compounds from virgin olive oil.     

The Infestation of Olive Fruits by Bactrocera oleae (Rossi) Modifies the Expression of Key Genes in the Biosynthesis of Volatile and Phenolic Compounds and Alters the Composition of Virgin Olive Oil

Bactrocera oleae, the olive fruit fly, is one of the most important pests affecting the olive fruit, causing serious quantitative and qualitative damage to olive oil production. In this study, the changes induced by B. oleae infestation in the biosynthesis of volatile and phenolic compounds in olive (cvs. Picual, Manzanilla, and Hojiblanca) have been analyzed. Despite cultivar differences, the oils obtained from infested fruits showed a significant increase in the content of certain volatile compounds such as (E)-hex-2-enal, ethanol, ethyl acetate, and β-ocimene and a drastic decrease of the phenolic contents. The impact of those changes on the inferred quality of the oils has been studied. In parallel, the changes induced by the attack of the olive fly on the expression of some key genes in the biosynthesis of volatile and phenolic compounds, such as lipoxygenase, β-glucosidase, and polyphenol oxidase, have been analyzed. The strong induction of a new olive polyphenol oxidase gene (OePPO2) explains the reduction of phenolic content in the oils obtained from infested fruits and suggest the existence of a PPO-mediated oxidative defense system in olives.     

Chemical changes in virgin olive oils as a function of crushing systems: Stone mill and hammer crusher

Olive oils were tested for their chemical composition in polyphenols, free fatty acids and volatile compounds as a function of the crushing systems, i.e. the stone mill and hammer crusher. The qualitative and quantitative HPLC/DAD analyses of the olive oils showed that luteolin and tyrosol were the most abundant identified phenolic compounds. The olive oil obtained by the hammer crusher had the highest concentration of phenolic compounds and ultimately the strongest antioxidant activity. Olives treated by the two crushing systems were observed by scanning electronic microscopy. Micrographs provide more evidence of the better cell cuts of olive fruits treated by hammer crushing, in contrast to stone mill where olive cell layers have been broken and damaged.     

Processing Effect and Characterization of Olive Oils from Spanish Wild Olive Trees (Olea europaea var. sylvestris)

Wild olive trees have important potential, but, to date, the oil from wild olives has not been studied significantly, especially from an analytical point of view. In Spain, the wild olive tree is called “Acebuche” and its fruit “Acebuchina”. The objective of this work is to optimize the olive oil production process from the Acebuchina cultivar and characterize the oil, which could be marketed as healthy and functional food. A Box–Behnken experimental design with five central points was used, along with the Response Surface Methodology to obtain a mathematical experimental model. The oils from the Acebuchina cultivar meet the requirements for human consumption and have a good balance of fatty acids. In addition, the oils are rich in antioxidants and volatile compounds. The highest extraction yield, 12.0 g oil/100 g paste, was obtained at 90.0 min and the highest yield of phenolic compounds, 870.0 mg/kg, was achieved at 40.0 °C, and 90.0 min; but the maximum content of volatile compounds, 26.9 mg/kg, was obtained at 20 °C and 30.0 min. The oil yield is lower than that of commercial cultivars, but the contents of volatile and phenolic compounds is higher.     

Analytical determination of polyphenols in olive oils

The increasing popularity of olive oil is mainly attributed to its high content of oleic acid, which may affect the plasma lipid/lipoprotein profiles, and its richness in phenolic compounds, which act as natural antioxidants and may contribute to the prevention of human disease. An overview of analytical methods for the measurement of polyphenols in olive oil is presented. In principle, the analytical procedure for the determination of individual phenolic compounds in virgin olive oil involves three basic steps: extraction from the oil sample, analytical separation, and quantification. A great number of procedures for the isolation of the polar phenolic fraction of virgin olive oil, utilizing two basic extraction techniques, LLE or SPE, have been included. The reviewed techniques are those based on spectrophotometric methods, as well as analytical separation (gas chromatography (GC), high-performance liquid chromatography (HPLC), and capillary electrophoresis (CE)). Many reports in the literature determine the total amount of phenolic compounds in olive oils by spectrophometric analysis and characterize their phenolic patterns by capillary gas chromatography (CGC) and, mainly, by reverse phase high-performance liquid chromatography (RP-HPLC); however, CE has recently been applied to the analysis of phenolic compound of olive oil and has opened up great expectations, especially because of the higher resolution, reduced sample volume, and analysis duration. CE might represent a good compromise between analysis time and satisfactory characterization for some classes of phenolic compounds of virgin olive oils.     

Essential Oil Volatile Fingerprint Differentiates Croatian cv. Oblica from Other Olea europaea L. Cultivars

Olive leaves are a highly available by-product from table olive and olive oil production. They are nowadays strongly valuable for their major bioactive compounds and their beneficial effects. To determine the differences between two Croatian domestic (Lastovka, Oblica) and two introduced (Leccino, Frantoio) cultivars, physical and chemical analysis of olive leaves were performed: surface area, color variability, total phenolic amounts, and essential oil volatile profiles were analyzed at three harvest periods. All cultivars greatly differed in surface area, with cv. Lastovka being the smallest. Color variability resulted in an overall decrease in darkness and amounts of green and yellow that could be attributed to a decrease in photosynthetic demand and chlorophyll content. The highest amount of total phenolic content occurred in the summer months, followed by a reduction until October. Essential oils volatiles were determined by GC-MS and showed great diversity not only amongst cultivars but also between harvest periods, with overall 45 compounds identified. Principal component analysis distinguished domestic cultivar Oblica from the other observed cultivars, mainly due to its essential oil volatile fingerprint. Compounds that differentiated cv. Oblica were aldehydes ((E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal, decanal), ketones ((E)-β-damascone, dihydrodehydro-β-ionone), sesquiterpenes (cyclosativene, α-copaene, α-muurolene) and saturated hydrocarbons (tetradecane, hexadecane). Essential oil volatile fingerprint attributed the highest to the biodiversity of domestic cv. Oblica through all three harvest periods.     

Simple and fast determination of phenolic compounds from different varieties of olive oil by nonaqueous capillary electrophoresis with UV‐visible and fluorescence detection

In this article, we proposed very simple procedures to analyze important phenolic compounds in olive oil samples from different olive varieties. A nonaqueous CE method has been employed. The main phenolic alcohols in virgin olive oil (tyrosol and hydroxytyrosol) and some among the most abundant secoiridoid aglycone derivatives (dialdehydic form of decarboxymethyl elenoic acid linked to hydroxytyrosol, an isomer of oleuropein aglycone and the dialdehydic form of decarboxymethyl elenoic acid linked to tyrosol) were determined by a direct injection into the capillary of the olive oil dissolved in 1‐propanol 1:1 v/v. For the determination of compounds present at lower concentrations, a very simple liquid–liquid extraction method with ethanol has been proposed. The extraction was performed using a relationship 5:1 w/v olive oil/ethanol to achieve the necessary preconcentration of the analytes and the ethanolic extracts were directly injected into the capillary to obtain a very important time reduction. Good recoveries were obtained with both the procedures, using an internal standard. Finally, these procedures were applied to the analysis of these compounds in extra virgin olive oil samples from different varieties of olive.     

Presence of virgin olive oil phenolic metabolites in human low density lipoprotein fraction: determination by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

The biological benefits of olive oil in preventing the oxidation of low density lipoprotein (LDL) would seem to be linked to its high monounsaturated fatty acid contents, but also to its respective phenolic compounds contents. One prerequisite to assess the in vivo physiological significance of phenolic compounds is to determine their presence in human LDL following the ingestion of virgin olive oil.In this work, olive oil phenolic metabolites were identified using high-performance liquid chromatography in tandem with electrospray mass spectrometry (HPLC-ESI-MS/MS) detection, after solid phase extraction (SPE). Quantitative methods were developed in carrying out linearity, precision, sensitivity and recovery tests. The results from two methods of LDL separation were compared and shorter LDL isolation procedure showed a better recovery for antioxidants compounds in LDL. The metabolites identified in LDL were: hydroxytyrosol monoglucuronide, hydroxytyrosol monosulfate, tyrosol glucuronide, tyrosol sulfate and homovanillic acid sulfate. The fact that olive oil phenolic metabolites are able to bind LDL strengthens claims that these compounds act as in vivo antioxidants.     

Effects of conventional heating on the stability of major olive oil phenolic compounds by tandem mass spectrometry and isotope dilution assay

The quality of olive oils is sensorially tested by accurate and well established methods. It enables the classification of the pressed oils into the classes of extra virgin oil, virgin oil and lampant oil. Nonetheless, it would be convenient to have analytical methods for screening oils or supporting sensorial analysis using a reliable independent approach based on exploitation of mass spectrometric methodologies. A number of methods have been proposed to evaluate deficiencies of extra virgin olive oils resulting from inappropriate technological treatments, such as high or low temperature deodoration, and home cooking processes. The quality and nutraceutical value of extra virgin olive oil (EVOO) can be related to the antioxidant property of its phenolic compounds. Olive oil is a source of at least 30 phenolic compounds, such as oleuropein, oleocanthal, hydroxytyrosol, and tyrosol, all acting as strong antioxidants, radical scavengers and NSAI-like drugs. We now report the efficacy of MRM tandem mass spectrometry, assisted by the isotope dilution assay, in the evaluation of the thermal stability of selected active principles of extra virgin olive oil.     

Novel Processes for the Extraction of Phenolic Compounds from Olive Pomace and Their Protection by Encapsulation

Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. This study aimed to point out a new approach for the integrated valorization of olive pomace by extracting the phenolic compounds and protecting them by encapsulation or incorporation in nanoemulsions. Innovative assisted extraction methods were evaluated such as microwave (MAE), homogenization (HAE), ultrasound (UAE), and high hydrostatic pressure (HHPAE) using various solvent systems including ethanol, methanol, and natural deep eutectic solvents (NADESs). The best extraction efficiency of phenolic compounds was achieved by using NADES as extraction solvent and in particular the mixture choline chloride-caffeic acid (CCA) and choline chloride-lactic acid (CLA); by HAE at 60 °C/12,000 rpm and UAE at 60 °C, the total phenolic content (TPC) of extracts was 34.08 mg gallic acid (GA)/g dw and 20.14 mg GA/g dw for CCA, and by MAE at 60 °C and HHPAE at 600 MPa/10 min, the TPC was 29.57 mg GA/g dw and 25.96 mg GA/g dw for CLA. HAE proved to be the best method for the extraction of phenolic compounds from olive pomace. Microencapsulation and nanoemulsion formulations were also reviewed for the protection of the phenolic compounds extracted from olive pomace. Both encapsulation techniques exhibited satisfactory results in terms of encapsulation stability. Thus, they can be proposed as an excellent technique to incorporate phenolic compounds into food products in order to enhance both their antioxidative stability and nutritional value.     

Detection of refined olive oil adulteration with refined hazelnut oil by employing NMR spectroscopy and multivariate statistical analysis

NMR spectroscopy was employed for the detection of adulteration of refined olive oil with refined hazelnut oil. Fatty acids and iodine number were determined by ¹H NMR, whereas ³¹P NMR was used for the quantification of minor compounds including phenolic compounds, diacylglycerols, sterols, and free fatty acids (free acidity). Classification of the refined oils based on their fatty acids content and the concentration of their minor compounds was achieved by using the forward stepwise canonical discriminant analysis (CDA) and the classification binary trees (CBTs). Both methods provided good discrimination between the refined hazelnut and olive oils. Different admixtures of refined olive oils with refined hazelnut oils were prepared and analyzed by ¹H NMR and ³¹P NMR spectroscopy. Subsequent application of CDA to the NMR data allowed the detection of the presence of refined hazelnut oils in refined olive oils at percentages higher than 5%. Application of the non-linear classification method of the binary trees offered better possibilities of measuring adulteration of the refined olive oils at a lower limit of detection than that obtained by the CDA method.     

A New Definition of the Term “High-Phenolic Olive Oil” Based on Large Scale Statistical Data of Greek Olive Oils Analyzed by qNMR

In the last few years, a new term, “High-phenolic olive oil”, has appeared in scientific literature and in the market. However, there is no available definition of that term regarding the concentration limits of the phenolic ingredients of olive oil. For this purpose, we performed a large-scale screening and statistical evaluation of 5764 olive oil samples from Greece coming from >30 varieties for an eleven-year period with precisely measured phenolic content by qNMR. Although there is a large variation among the different cultivars, the mean concentration of total phenolic content was 483 mg/kg. The maximum concentration recorded in Greece reached 4003 mg/kg. We also observed a statistically significant correlation of the phenolic content with the harvest period and we also identified varieties affording olive oils with higher phenolic content. In addition, we performed a study of phenolic content loss during usual storage and we found an average loss of 46% in 12 months. We propose that the term high-phenolic should be used for olive oils with phenolic content > 500 mg/kg that will be able to retain the health claim limit (250 mg/kg) for at least 12 months after bottling. The term exceptionally high phenolic olive oil should be used for olive oil with phenolic content > 1200 mg/kg (top 5%).     

A Review of the Effects of Olive Oil-Cooking on Phenolic Compounds

The fate of phenolic compounds in oil and food during cooking vary according to the type of cooking. From a nutritional point of view, reviews largely suggest a preference for using extra-virgin olive oil at a low temperature for a short time, except for frying and microwaving, for which there appears to be no significant advantages compared to olive oil. However, due to the poorly pertinent use of terminology, the different protocols adopted in studies aimed at the same objective, the different type and quality of oils used in experiments, and the different quality and quantity of PC present in the used oils and in the studied vegetables, the evidence available is mainly contradictory. This review tries to reanalyse the main experimental reports on the fate, accessibility and bioavailability of phenolic compounds in cooking oils and cooked vegetables, by considering different cooking techniques and types of oil and foods, and distinguishing experimental findings obtained using oil alone from those in combination with vegetables. The re-analysis indicates that incomplete and contradictory observations have been published in the last few years and suggests that further research is necessary to clarify the impact of cooking techniques on the phenolic compounds in oil and vegetables during cooking, especially when considering their nutritional properties.     

Nutraceutical Potential of Leaf Hydro-Ethanolic Extract of the Edible Halophyte Crithmum maritimum L.

Aromatic halophytes represent an exceptional source of natural bioactive compounds for the food industry. Crithmum maritimum L., also known as sea fennel, is a halophyte plant colonizing cliffs and coastal dunes along Mediterranean and Atlantic coasts. It is well known to produce essential oils and polyphenols endowed with antioxidant and biological effects. The present work reports the phytochemical profile, as well as antioxidant, antimicrobial and antimutagenic properties of C. maritimum leaf hydro-alcoholic extract. From LC-ESI-MS analysis, eighteen phenolic compounds were depicted in sea fennel extract and the amount of total phenolic content exceeds 3% DW. Accordingly, C. maritimum extract showed strong antioxidant activities, as evidenced by in vitro (DPPH, ORAC, FRAP) and ex vivo (CAA-RBC and hemolysis) assays. An important antimicrobial activity against pathogenic strains was found as well as a strong capacity to inhibit Staphylococcus aureus (ATCC 35556) biofilm formation. Sea fennel extracts showed a significant decrease of mutagenesis induced by hydrogen peroxide (H₂O₂) and menadione (ME) in Saccharomyces cerevisiae D7 strain. In conclusion, our results show that C. maritimum is an exceptional source of bioactive components and exert beneficial effects against oxidative or mutagenic mechanisms, and pathogenic bacteria, making it a potential functional food.     

Extra Virgin Olive Oil Secoiridoids Modulate the Metabolic Activity of Dacarbazine Pre-Treated and Treatment-Naive Melanoma Cells

Nowadays, many individuals, whether healthy or diagnosed with disease, tend to expose themselves to various easily accessible natural products in hopes of benefiting their health and well-being. Mediterranean populations have traditionally used olive oil not only in nutrition but also in cosmetics, including skincare. In this study, the phenolic profile—composed of twelve compounds altogether, including the secoiridoids oleocanthal (OCAL) and oleacein (OCEIN)—of extra virgin olive oil (EVOO) from autochthonous cultivars from Croatia was determined using ¹H qNMR spectroscopy and HPLC-DAD analysis, and its biological activity was investigated in melanoma cell lines. The EVOO with the highest OCEIN content had the strongest anti-cancer activity in A375 melanoma cells and the least toxic effect on the non-cancerous keratocyte cell line (HaCaT). On the other hand, pure OCAL was shown to be more effective and safer than pure OCEIN. Post-treatment with any of the EVOO phenolic extracts (EVOO-PEs) enhanced the anti-cancer effect of the anti-cancerous drug dacarbazine (DTIC) applied in pre-treatment, while they did not compromise the viability of non-cancerous cells. The metastatic melanoma A375M cell line was almost unresponsive to the EVOO-PEs themselves, as well as to pure OCEIN and OCAL. Our results demonstrate that olive oils and/or their compounds may have a potentially beneficial effect on melanoma treatment. However, their usage can be detrimental or futile, especially in healthy cells, due to inadequately applied concentrations/combinations or the presence of resistant cells.     

LC‐DAD‐ESI‐MS/MS–based phenolic profiling and antioxidant activity in Turkish cv. Nizip Yaglik olive oils from different maturity olives

The current study was designed to find out how olive maturity indices (2.5, 3.5, and 4.5) affect the individual phenolic compounds and antioxidant potencies of olive oils produced from cv. Nizip Yaglik olives. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode was utilized for the determination of phenolic composition qualitatively and quantitatively. Findings asserted a quite similar phenolic profile (14 phenols) depending on the various phenolic groups in all oils, while the concentration of total and individual phenolic compounds revealed significant differences between the samples statistically (p < 0.05). Among the individual phenolic classes in all samples, secoiridoids were the most prevailing group and their total content showed a clear significant decline as the olive fruits get ripened. Antioxidant potency values showed a clear diminution attitude during the maturation of the olives. The principal component analysis revealed that oils were discriminated from each other according to phenolic compounds and antioxidant potencies. Moreover, oils obtained from the unripe and medium‐ripe fruits possessed a very good quality marked by their elevated phenolic levels.     

New possibilities for the valorization of olive oil by-products

In this contribution, the capabilities of pressurized liquid extraction (PLE) using food-grade solvents, such as water and ethanol, to obtain antioxidant extracts rich on polyphenolic compounds from olive leaves are studied. Different extraction conditions were tested, and the PLE obtained extracts were characterized in vitro according to their antioxidant capacity (using the DPPH radical scavenging and the TEAC assays) and total phenols amounts. The most active extracts were obtained with hot pressurized water at 200 °C (EC(50) 18.6 μg/mL) and liquid ethanol at 150 °C (EC(50) 27.4 μg/mL), attaining at these conditions high extraction yields, around 40 and 30%, respectively. The particular phenolic composition of the obtained extracts was characterized by LC-ESI-MS. Using this method, 25 different phenolic compounds could be tentatively identified, including phenolic acids, secoiridoids, hydroxycinnamic acid derivatives, flavonols and flavones. Among them, hydroxytyrosol, oleuropein and luteolin-glucoside were the main phenolic antioxidants and were quantified on the extracts together with other minor constituents, by means of a UPLC-MS/MS method. Results showed that using water as extracting agent, the amount of phenolic compounds increased with the extraction temperature, being hydroxytyrosol the main phenolic component on the water PLE olive leaves extracts, reaching up to 8.542 mg/g dried extract. On the other hand, oleuropein was the main component on the extracts obtained with ethanol (6.156-2.819 mg/g extract). Results described in this work demonstrate the good possibilities of using PLE as a useful technique for the valorization of by-products from the olive oil industry, such as olive leaves.     

A Potential Valorization Strategy of Wine Industry by-Products and Their Application in Cosmetics—Case Study: Grape Pomace and Grapeseed

Grape pomace and grapeseed are agro-industrial by-products, whose inadequate treatment generates socioeconomic and environmental concerns. Nevertheless, it is possible to valorize them by extracting their bioactive compounds, such as antioxidants (phenolic compounds), vitamin E and fatty acids. The bioactive compounds were extracted using solid-liquid extraction. The yields for phenolic compounds were 18.4 ± 0.4% for grape pomace, and 17.4 ± 0.4%, for grapeseed. For the oil, the yields were 13.3 ± 0.2% and 14.5 ± 0.3% for grape pomace and grapeseed. Antioxidant capacity was assessed by the assay with 2,2-diphenyl-1-picrylhydrazyl (DPPH), and showed that phenolic extract has higher antioxidant capacity than the oils. Grape pomace and grapeseed extracts exhibit, correspondingly, values of 90.8 ± 0.8 and 87.5 ± 0.5 of DPPH inhibition and IC₅₀ of 48.9 ± 0.5 and 55.9 ± 0.7 μg_extract·mL_DPPH⁻¹. The antimicrobial capacity was assessed by the disk diffusion test, and revealed that, phenolic extracts inhibit the growth of Staphylococcus aureus and Staphylococcus epidermidis. The obtained extracts were incorporated in 10 face cream formulations, with slight modifications in quantities of formulation stabilizers. Their stability was studied for 35 days, and this revealed the possibility of incorporating extracts and oils obtained from by-products as antioxidants in cosmetics, and replacing synthetic ones. As a future recommendation, microencapsulation of the extracts should be performed, in order to increase their stability.     

Liquid-liquid and solid-phase extractions of phenols from virgin olive oil and their separation by chromatographic and electrophoretic methods

The high oxidative stability of virgin olive oil is related to its high monounsaturated/polyunsaturated ratio and to the presence of antioxidant compounds, such as tocopherols and phenols. In this paper, the isolation of phenolic compounds from virgin olive oil, by different methods, was tested and discussed. Particularly liquid-liquid and solid-phase extraction methods were compared, assaying, for the latter, three stationary phases (C8, C18 and Diol) and several elution mixtures. Quantification of phenolic and o-diphenolic substances in the extracts was performed by the traditional Folin-Ciocalteau method and the sodium molybdate reaction, respectively. Furthermore, the quantification of phenolic compounds in the extracts and in a standard mixture was carried out both with diode array and mass spectrometric detection and capillary zone electrophoresis.