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Flavonoids, secondary plant metabolites with many health-promoting properties, including antioxidant, are a valuable component of food products, especially functional foods. In the latter, plant extracts are commonly used, the properties of which are attributed to the characteristic main ingredients. However, in a mixture the antioxidant properties of the individual ingredients do not always show an additive effect. This paper presents and discusses the antioxidant properties of naturally occurring flavonoid aglycones and their binary mixtures. In the experiments, model systems were used that differed in the volume of the alcoholic antioxidant solution in the measuring system and its concentration in the range in which it occurs in nature. Antioxidant properties were determined by ABTS and DPPH methods. The presented data proved that the dominant resultant effect in the mixtures is antioxidant antagonism. The magnitude of the observed antagonism depends on the mutual relations of individual components, their concentrations and the method used to assess antioxidant properties. It was shown that the observed non-additive antioxidant effect of the mixture results from the formation of intramolecular hydrogen bonds between phenolic groups of the antioxidant molecule. The presented results may be useful in the context of proper design of functional foods. [ABSTRACT FROM AUTHOR]

Nature is a valuable source of anti-oxidants that have a health-promoting effect by inhibiting various undesirable changes leading to cell degradation and, consequently, potential disease ailments. One of them is gallic acid which has been used as a healing agent since ancient times. Currently, due to various beneficial properties, this compound is considered to be one of the main phenolic acids of great importance in numerous industries. It is commonly used as a substance protecting against the harmful effects of UV radiation, an astringent in cosmetic preparations, and a preservative in food products. Therefore, gallic acid is now deemed essential for both human health and industry. Increasingly better methods of its isolation and analysis are being developed, and new solutions are being sought to increase its production. This review, presenting a concise characterization of gallic acid, updates the knowledge about its various biological activities and methods used for its isolation and determination, including chromatographic and non-chromatographic methods. [ABSTRACT FROM AUTHOR]

Abstract Vitamin K is one of the many health-promoting substances whose impact on the human body has been underestimated until recently. However, recently published research results have changed this situation, prompting some researchers to consider it a new panacea for diseases of old age. The result is a significant increase in interest in the accurate analysis of vitamin K in various types of samples, ranging from food, through dietary supplements, to biological matrices and clinical trials, both observational and interventional. This review summarizes the current state of knowledge about the proven and speculated biological activity of vitamin K and its importance for the world’s aging societies, including the methods used for its isolation and analysis in various matrices types. Of all the analytical methods, the currently preferred methods of choice for the direct analysis of vitamin K are chromatographic methods, in particular liquid chromatography-tandem mass spectrometry. This technique, despite its sensitivity and selectivity, requires an appropriate stage of sample preparation. As there is still room for improvement in the efficiency of these methods, especially at the sample preparation stage, this review shows the directions that need to be taken to make these methods faster, more efficient and more environmentally friendly. [ABSTRACT FROM AUTHOR]

Chlorogenic acid (CQA) is one of phenolics commonly found in higher plants, possessing numerous health-promoting effects on humans. Unfortunately, it is easily degraded/transformed into other substances during extraction. Therefore, its reliable analysis requires a special approach that does not involve high temperatures. This paper presents a very simple method of CQA isolation using the sea sand disruption method with subsequent purification of the extract using the ion-pair solid-phase extraction process, followed by HPLC–DAD detection. It was found that control of the ion pairing reagent concentration and sample pH is crucial to improve purification, and that the best results, with recovery exceeding 98%, were obtained for 0.05 M tetrabutylammonium bisulfate at pH 7 when the ion pairs were formed directly in the extract and eluted from the C18 sorbent using an acidified methanol–water mixture. The practical potential of the developed procedure was verified by using it for CQA isolation from different plants. The approach represents one of the contemporary analytical trends and current advances in the solid phase extraction, in which several sorption extraction techniques are combined to ensure high-quality analytical results. [ABSTRACT FROM AUTHOR]

In this study, to increase the content of quercetin in the isolates obtained from the white and red onion scales, in accordance with the zero waste philosophy, using water as an environmentally and healthy friendly extractant, a mathematical model was constructed, based on the Central Composite Design. The suitability of the model for the accurate and quick study of complex relationships was demonstrated by obtaining a statistically insignificant difference in the yield predicted by the model and that determined experimentally under optimal extraction conditions, i.e., 44.14 mg/g (33.57 mg/g) and 45.54 mg/g (33.31 mg/g) for white (red) onion scales, respectively. To present the obtained isolates applicability, their biological activity was assessed in terms of antioxidant activity and antifungal activity against various fungi, showing properties that are sufficient to encourage the use of this material, previously treated as worthless waste, for the production of various functional ingredients, including functional food additives. Moreover, they can be also used to produce safe and effective protectants meeting the GRAS criteria. [ABSTRACT FROM AUTHOR]

Introduction: Effective diagnosis of cardiovascular diseases requires the right tools to be used enabling selective and sensitive analysis of their biomarkers. One of them is homocysteine (Hcy), nowadays determined by immunoassays and chromatographic methods. This study aims to compare the results obtained by direct chemiluminescence immunoassay (CLIA) and high performance liquid chromatography with fluorescent detection (HPLC-FD) using commercial kits. Materials and methods: Homocysteine concentration was determined in serum samples obtained from 101 individuals, using Atellica IM HCY (Siemens Healthineers, Erlangen, Germany) and HCY in plasma/serum - HPLC-FD (Chromsystems Instruments & Chemicals GmbH, Gräfelfing, Germany) tests validated for routine analysis. The latter was applied as a reference method. The comparability and agreement between the tested methods were evaluated using the Passing-Bablok (PB) regression analysis and the Bland-Altman (BA) method of the differences analysis. Results: Studies showed that CLIA gives higher Hcy concentrations (15.7 ± 4.14 µmol/L). Passing-Bablok regression analysis of the results obtained with CLIA (y) compared with HPLC-FD (x) yielded an intercept of 0.22 (95%CI: - 2.16 to 2.46) and slope of 1.58 (95%CI: 1.33 to 1.87). Bland-Altman analysis demonstrated a systematic positive bias for CLIA of 5.85 ± 2.77 µmol/L. Conclusions: Methods disagreement precludes their interchangeability. Lower Hcy values by HPLC-FD result from its greater selectivity. High performance liquid chromatography with fluorescent detection should be considered as preferential method for analysing Hcy in blood serum as well as the recommended reference method for routine clinical analysis. This fact, however, imposes the need to establish new reference ranges. [ABSTRACT FROM AUTHOR]

The green husk is one of the major wastes produced during the walnut (Juglans regia L.) cultivation. However, the results presented in this article may contribute to extension of their usefulness as new and safe plant protection products. The results confirmed the activity of the walnut green husk extracts against plant (Alternaria alternata, Rhizoctonia solani, Botrytis cinerea, Fusarium culmorum, Phytophthora cactorum) and bee (Ascosphaera apis) pathogenic fungi, and showed that the extraction conditions differentiate the properties of the obtained isolates. The increase in the isolation temperature leads to a significant reduction in the antifungal activity of the extracts. The change of the extractant type modifies the resistance of individual fungi. The observed variations in the properties are consistent with the change of juglone content in these extracts. However, considering the juglone concentration provided 50% inhibition of the growth of individual mycelia, the observed differentiation of the antifungal properties of extracts should not be associated only with the juglone content. This observation, supported by the results obtained using gas chromatography coupled to mass spectrometry (GC-MS) and liquid chromatography coupled to mass spectrometry (LC-MS), suggests a synergistic effect of the other components on the antifungal activity of walnut green husk extracts. [ABSTRACT FROM AUTHOR]

One of the most important issues considered in ecotoxicology is the elevated accumulation of different elements in soil as a consequence of anthropogenic activities. In this paper, determination of nine elements in soil obtained from three different forest complexes (sycamore, beech, and spruce) in urbanized and non-urbanized regions of Tatra National Park is presented. Additionally, a comprehensive presentation of detailed results of correlation analyses between individual elements in accordance to each valley, as well as to selected species of trees, is shown. Speciation studies included chemical forms of the following elements: Fe, Mn, Zn, Cu, Pb, Cd, Ni, Cr, Co. Soil extracts were obtained in accordance with Rudd’s methodology and all species were determined using atomic absorption spectrophotometry (AAS). The study compares the content of selected chemical forms (exchangeable and adsorbed, organic solutions and carbonates) of chosen metals in soil of four valleys of Tatra National Park: Chochołowska, Strążyska, Mała Łąka, and Kościeliska. The first three (group A) are considered as non-urbanized areas, whereas the last four (group B), on the account of many home fireplaces located there, as urbanized areas. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present in the most comprehensive way the facts about the application of PLE in the analysis of secondary metabolites in plants. It is true that due to its specific extraction conditions, PLE is one of the most effective and versatile techniques of plant constituents isolation. It is also true that it has popularized the use of aqueous organic mixtures, and even water alone, for the extraction of nonpolar compounds. Yet, the same specific extraction conditions can lead to erroneous results of plant constituent content analysis. Disclosure of new facts about the application of PLE in the analysis of secondary plant metabolites provides an insight into an often overlooked aspect of extraction of active compounds from plants. • This review updates knowledge about the applicability of PLE. • It discusses the effectiveness and usefulness of PLE in the context of its achievements. • It discloses the limitations of PLE in the plant constituents content analysis. • Knowing all these facts can lead to the creation of a perfect method with a good method. [ABSTRACT FROM AUTHOR]

Abstract The aim of this paper was to present the diversity of analytical challenges in which the MSPD technique is useful and the variety of sorbents that are currently applied to meet these challenges with particular emphasis on new research areas in which the MSPD process started to be applied. In addition, the paper presents new tools to improve both the MSPD yields using the MSPD processes supported by centrifugation, ultrasound, microwave and magnetism and its selectivity combining MSPD with other extraction techniques in particular, with microextraction ones, such as liquid-liquid microextraction dispersion or homogeneous liquid-liquid microextraction. Facing the problem of the increased urgency for further reduction of sample preparation costs and organic solvent usage, alternative MSPD approaches such as the solventless MSPD mode and MSPD with sand used as a dispersing material in the so-called sea sand dispersion method were discussed. Highlights • This review updates knowledge about the applicability of MSPD. • It discuss the versatility and flexibility of MSPD in the context of its achievements and limitations. • Indicates new research areas in which MSPD began to be applied. • In addition, indicates those that in the near future should use this simple process. [ABSTRACT FROM AUTHOR]

Reliable plant analysis is a challenging task due to the physical character and chemical complexity of plant matrices. First of all, it requires the application of a proper sample preparation procedure to fully isolate the analyzed substances from the plant matrix. The high-temperature liquid-solid extraction is commonly applied for this purpose. In the light of recently published results, however, the application of high-temperature extraction for polyphenolics analysis in plants is disputable as it causes their transformation leading to erroneous quantitative estimations of these compounds. Experiments performed on different plants show that the transformation/degradation of quercetin and its glycosides is not induced by sea sand disruption method (SSDM) and prove the method to be most appropriate for the estimation of quercetin and its derivatives in plants. What is more, the application of SSDM in plant analysis allows the researcher, to determine which quercetin derivatives are native plant components and what is their true concentration. In other word, the application of SSDM in plant analysis eliminates errors in the study of plant metabolism involving quercetin and its derivatives. [ABSTRACT FROM AUTHOR]

Chlorogenic acids (CQAs), the esters of caffeic acid and quinic acid, are biologically important phenolic compounds present in many plant species. Nowadays much is known from their prohealth properties, including anti-cancer activity. Yet, the supposition that they may be helpful in fighting obesity and modify glucose-6-phosphatase involved in glucose metabolism have led to a revival of research on CQAs properties and their natural occurrence. Much attention is also paid to the proper analysis of CQAs content in plants and plant products due to the fact that the main CQAs representative in nature i.e. 5-O-caffeoylquinic acid (5-CQA) is commonly employed as a quality marker in the control of various natural products. The common procedures used so far for CQAs determination in plants involve conventional long lasting solvent extraction realized at higher temperatures prior to chromatographic analysis. The drawbacks associated to the conventional extraction techniques have led to the search for new alternative extraction processes that additionally could improve extracts quality. The latter is particularly important as regards CQAs applications, and the fact that these compounds easily transform/degrade to others. According to reports, the conventional heating of 5-CQA in the presence of water causes its isomerization and transformation. The reports prove that 5-CQA not only isomerizes to 3- and 4-O-caffeoylquinic acid, but also undergoes other transformations such as esterification and reactions with water. Hence, in the attempt to improve the process of chlorogenic acids extraction and to make it more effective and environmentally friendly, innovative so-called "enhanced" techniques of extraction have been recently developed and applied. To guarantee the proper analysis of compounds with very similar properties forming the chlorogenic acids family and their numerous transformation/degradation products, hyphenated techniques, in particular LC-MS, are currently being used. The purpose of this review is to summary and overview of the sources, properties, and methods which have been developed to improve the extraction and analysis of chlorogenic acids in plants and plant products, with particular reference to 5-CQA and 1,3-di- CQA as these compounds of the CQAs family with many beneficial effects on human health. [ABSTRACT FROM AUTHOR]

This paper proposes and shows the analytical capabilities of a new variant of matrix solid phase dispersion (MSPD) with the solventless blending step in the chromatographic analysis of plant volatiles. The obtained results prove that the use of a solvent is redundant as the sorption ability of the octadecyl brush is sufficient for quantitative retention of volatiles from 9 plants differing in their essential oil composition. The extraction efficiency of the proposed simplified MSPD method is equivalent to the efficiency of the commonly applied variant of MSPD with the organic dispersing liquid and pressurized liquid extraction, which is a much more complex, technically advanced and highly efficient technique of plant extraction. The equivalency of these methods is confirmed by the variance analysis. The proposed solventless MSPD method is precise, accurate, and reproducible. The recovery of essential oil components estimated by the MSPD method exceeds 98%, which is satisfactory for analytical purposes. [ABSTRACT FROM AUTHOR]

Pressurized liquid extraction (PLE) is considered as an effective and quick sample preparation method, especially in plant analysis. This quick extraction process favors the isolation of compounds for which long exposure time in high temperatures is undesirable. However, despite this advantage, the application of PLE for plant compounds extraction involves certain problems, such as instability of the compounds. The obtained data proved that even in short-lasting PLE, quercetin 4'-glucoside undergoing the hydrolytical degradation process produces the corresponding aglycon quercetin when water is a component of the applied extractant. The increase of water content in methanol-water extractant mixture heightens the transformation degree of quercetin 4'-glucoside into quercetin and increases its concentration in the PLE extracts. The degradation is accelerated by increased extraction temperature and time. In plant samples, the degradation of quercetin 4'-glucoside is much higher because of the plant matrix effects. The presented results explain why extraction of quercetin from plants by pure methanol is less efficient than by water containing alcohol solutions. More importantly, they prove that the application of water-alcohol extractant during sample preparation leads to the hydrolytical degradation of glycosides to aglycones, and, as a consequence, to false conclusions in plant analysis. [ABSTRACT FROM AUTHOR]

The analytical procedures for determining plant constituents involve the application of sample preparation methods to fully isolate and/or pre-concentrate the analyzed substances. High-temperature liquid extraction is still applied most frequently for this purpose. The present paper shows that high-temperature extraction cannot be applied for the analysis of chlorogenic acids (CQAs) and their derivatives in plants as it causes the CQAs transformation leading to erroneous quantitative estimations of these compounds. Experiments performed on different plants (black elder, hawthorn, nettle, yerba maté, St John’s wort and green coffee) demonstrate that the most appropriate method for the estimation of CQAs/CQAs derivatives is sea sand disruption method (SSDM) because it does not induce any transformation and/or degradation processes in the analyzed substances. Owing to the SSDM method application we found that the investigated plants, besides four main CQAs, contain sixteen CQAs derivatives, among them three quinic acids. The application of SSDM in plant analysis not only allows to establish a true concentration of individual CQAs in the examined plants but also to determine which chlorogenic acids derivatives are native plant components and what is their concentration level. What is even more important, the application of SSDM in plant analysis allows to eliminate errors that may arise or might have arisen in the study of chlorogenic acids and their derivatives in plant metabolism. [ABSTRACT FROM AUTHOR]

This study deals with the sea sand disruption method (SSDM) in sample preparation for chromatographic analysis of quercetin in different plants. Several SSDM variables were tested in relation to quercetin recovery: sample to sand mass ratio, type of dispersing liquid, volume of the solvent applied for analyte elution, and the time of grinding. The optimized procedure has been applied for the extraction of quercetin from the edible and inedible parts of different varieties of onion, apples, and tea. The SSDM results are comparable with those obtained by pressurized liquid extraction, regarded as one of the most effective sample preparation techniques. The presented results show that the hydrolysis of quercetin glycoside form in SSDM conditions does not occur or is negligible. Hence, the method is especially useful when the estimation of the real amount of aglycones in plants is required. [ABSTRACT FROM AUTHOR]

Chlorogenic acids (CQAs) are phenolic compounds naturally occurring in all higher plants. They are potentially useful in pharmaceuticals, foodstuffs, food additives, and cosmetics due to their recently suggested biomedical activity. Hence, research interest in CQA properties, their isomers, and natural occurrence has been growing. Pressurized liquid extraction (PLE) is regarded as an effective and quick sample preparation method in plant analysis. The short time of PLE decreases the risk of chemical degradation of extracted compounds, thus increasing the attractiveness of its application. However, PLE applied for plant sample preparation is not free from limitations. We found that fr-ans-5-O-caffeoylquinic acid (trans-5-CQA), the main CQA isomer, isomerizes to 3- and 4-O-caffeoylquinic acids and undergoes transesterification, hydrolysis, and reaction with water even in rapid PLE. Moreover, the number and concentration of trans-5-CQA derivatives formed in PLE strongly depends on extractant composition, its pH, and extraction time and temperature. It was not possible to find the PLE conditions in which the transformation process of trans-5-CQA would be eliminated. [ABSTRACT FROM AUTHOR]

Silymarin, a mixture of flavonolignans exhibiting many pharmacological activities, is obtained from the fruits of milk thistle (Silybum marianum L. Gaertner). Due to the high lipid content in thistle fruits, the European Pharmacopoeia recommends a two-step process of its extraction. First, the fruits are defatted for 6 h, using n-hexane; second, silymarin is extracted with methanol for 5 more hours. The presented data show that this extremely long traditional Soxhlet extraction process can be shortened to a few minutes using pressurized liquid extraction (PLE). PLE also allows to eliminate the defatting stage required in the traditional procedure, thus simplifying the silymarin extraction procedure and preventing silymarin loss caused by defatting. The PLE recoveries obtained under the optimized extraction conditions are clearly better than the ones obtained by the Pharmacopoeia-recommended Soxhlet extraction procedure. The PLE yields of silychristin, silydianin, silybin A, silybin B, isosilybin A and isosilybin B in acetone are 3.3, 6.9, 3.3, 5.1, 2.6 and 1.5 mg/g of the non-defatted fruits, respectively. The 5-h Soxhlet extraction with methanol on defatted fruits gives only ∼72% of the silymarin amount obtained in 10 min PLE at 125°C. [ABSTRACT FROM AUTHOR]

The influence of different purge times on the yield of the main essential oil constituents of rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and chamomile (Chamomilla recutita L.) was investigated. The pressurized liquid extraction process was performed by applying different extraction temperatures and solvents. The results presented in the paper show that the estimated yield of essential oil components extracted from the plants in the pressurized liquid extraction process is purge time-dependent. The differences in the estimated yields are mainly connected with the evaporation of individual essential oil components and the applied solvent during the purge; the more volatile an essential oil constituent is, the greater is its loss during purge time, and the faster the evaporation of the solvent during the purge process is, the higher the concentration of less volatile essential oil components in the pressurized liquid extraction receptacle. The effect of purge time on the estimated yield of individual essential oil constituents is additionally differentiated by the extraction temperature and the extraction ability of the applied solvent. [ABSTRACT FROM AUTHOR]

Hydroxyanthraquinones represent a group of pharmacologically active compounds characteristic for plants of the Rumex and Rheum genera. These compounds in the human intestine act as laxative compounds. As they cause the greatest side effects and are often abused by the public, their accurate analysis in plants and plant-derived laxatives is much needed. To isolate compounds from plants, pressurized liquid extraction (PLE) is frequently applied. The technique has been regarded, so far, as very effective, even in isolation of sensitive compounds for which exposure time in high temperature has a negative impact. This work demonstrates some interesting and surprising results accompanying PLE of hydroxyanthraquinones from the Rumex crispus L. root using methanol/water mixtures as extractant. The presented results demonstrate that glycoside forms of hydroxyanthraquinones (emodin -8 -O-β-D-glucopyranoside, chrysophanol -8 -O-β-D-glucopyranoside, and physcion -8 -O-β-D-glucopyranoside) are hydrolytically unstable even in the short-lasting PLE. The increase of water concentration in the extractant leads to the increase of the transformation degree of the glycoside forms to the corresponding aglycones (emodin, chrysophanol, and physcion), increasing the concentration of the latter. The rise in the PLE temperature accelerates the hydrolytical degradation of the glycoside forms. The extension of the extraction time also intensifies this process. The presented results show that extraction of glycosides using extractants containing water can lead to false conclusions about the chemical composition of plants. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this study it was shown that the fungistatic and antioxidant activities of onion extracts are related to the type of liquid used as the extractant and the technique of its preparation. A change in the antioxidant properties of white and red onion extracts was demonstrated with the change of the temperature of the pressurized hot water extraction process, which can be easily related to the changes accompanying the process of thermal processing of vegetables and fruits during cooking. Owing to the experimental and mathematical approaches concerning both the main and characteristic components of onions, i.e., quercetin and phenols, respectively, with the biological activity of the extracts, it was possible to demonstrate the significant share of these compounds in the antifungal and antioxidant properties of the extracts. Considering that the research was carried out, inter alia, on onion husks, demonstrating a very high potential of biological properties of this waste material from agricultural production, the research results presented in the paper should encourage the popularization of the use of this so far underestimated raw material for the production of various functional materials. [ABSTRACT FROM AUTHOR]

Abstract: 2,2′-Diphenyl-1-picrylhydrazyl (DPPH ) method is commonly applied for the estimation of antioxidant activity of single compounds and their mixtures. The method is based on the spectrophotometric measurement of DPPH concentration changes resulting from the DPPH reaction with an antioxidant. The amount of remaining DPPH in the examined system is a measure of the antioxidative activity of compounds. The study shows that the type and amount of solvent used for the antioxidant dissolution, water content, and hydrogen or metal ion concentration in the measuring system significantly influence the differences in the amount of unreacted DPPH . The presence of ethyl acetate or dioxane or metal ions in the system decreases the kinetics of the reaction between DPPH and butylohydroxytoluene in relation to its kinetics in the system containing only methanolic solutions. The opposite effect is observed for water, low concentration of chloroform or hydrogen ions. The presented relationships confirm the necessity of standardising the DPPH method and show the complexity of the problem, even in very simple DPPH /antioxidant systems. [Copyright &y& Elsevier]

Four types of solvent extraction methods (ultrasound and microwave assisted extraction, pressurized liquid extraction, and extraction in the Soxhlet apparatus) for paclitaxel, cephalomannine, and 10-deacetylbaccatin, taxoids recovered from common yew twigs, were compared. By use of pressurised liquid extraction (PLE), the most effective extractant of taxoids was determined. HPLC was used for the analysis of the extracts. Comparison of the obtained results revealed differences in the extraction power of the applied methods. The greatest yields were obtained by multiple PLE, which can be recommended as the best sample preparation method for taxoids analysis in yew twigs. [ABSTRACT FROM AUTHOR]

Abstract: The antioxidant properties of alcoholic extracts from the leaves, berries and flowers of Sambucus nigra L. are estimated by means of DPPH and β-carotene/linoleic acid methods, and considered in relation to the extraction temperature (in the range 20–200°C) and to the level of flavonoids most representative for this plant. The extracts of S. nigra act as antioxidants neutralizing the activities of free radicals and inhibiting the co-oxidation reactions of linoleic acid and β-carotene. There is no direct correlation between the level of flavonoids in the extracts and their antioxidant activity. The data presented show that the extraction temperature strongly influences the antioxidant properties of the extracts, especially in the case of leaves. [Copyright &y& Elsevier]

Summary: The effect of heavy metal stress as a potent abiotic elicitor for triggering an accumulation of jasmonic acid (JA) was investigated. Copper and cadmium in in vivo conditions induced accumulation of jasmonates in mature leaves of Arabidopsis thaliana and in young and oldest Phaseolus coccineus plants. The dynamics of jasmonate accumulation showed a biphasic character in both plants. In the first phase, after 7 (A. thaliana) or 14h (P. coccineus) of exposure to Cu or Cd, a rapid increase of JA level occurred, followed by a rapid decrease observed during 7 successive hours. In the next phase, a repeated but slow increase of JA content occurred. The heavy metal stress induced in particular a more stable (3R,7R) form of jasmonates. These results indicate that JA is connected with the mechanism of toxic action of both heavy metals in plants, differentially reacting to exogenous JA and possessing variable dynamics depending on the plants studied as well as their growth stage. [Copyright &y& Elsevier]

Abstract: Pressurised liquid extraction (PLE) is recognised as one of the most effective sample preparation methods. Despite the enhanced extraction power of PLE, the full recovery of an analyte from plant material may require multiple extractions of the same sample. The presented investigations show the possibility of estimating the true concentration value of an analyte in plant material employing one-cycle PLE in which plant samples of different weight are used. The performed experiments show a linear dependence between the reciprocal value of the analyte amount (E*), extracted in single-step PLE from a plant matrix, and the ratio of plant material mass to extrahent volume (m p/V s). Hence, time-consuming multi-step PLE can be replaced by a few single-step PLEs performed at different (m p/V s) ratios. The concentrations of rutin in Sambucus nigra L. and caffeine in tea and coffee estimated by means of the tested procedure are almost the same as their concentrations estimated by multiple PLE. [Copyright &y& Elsevier]

Abstract: A broad spectrum of sample preparation methods is currently used for the isolation of pharmacologically active compounds from plant and herbal materials. The paper compares the effectiveness of infusion, microwave assisted solvent extraction (MASE), matrix solid-phase dispersion (MSPD) and pressurised liquid extraction (PLE) as sample preparation methods for the isolation of caffeine from green tea leaves. The effect of PLE variables, such as extraction temperature, pressure and time, on the yield of caffeine from the investigated matrix is discussed. The obtained results revealed that PLE, in comparison with other sample preparation methods applied, has significantly lower efficacy for caffeine isolation from green tea leaves. The evaluation of PLE conditions leads to the conclusion that elevated pressure applied in the PLE process is the factor hindering the extraction. [Copyright &y& Elsevier]

The paper presents the results of calorimetric measurements and surface excess adsorption isotherms for adsorption process of n-butanol from n-hexane on controlled porosity glasses of different mean pore diameters. The pore diameter was found to have very small effect on the adsorption heat, while it affects the desorption heat recorded by the flow microcalorimeter. Moreover, in the region of very low alcohol concentration in solution, the heat of adsorption exhibits sharp maximum for both narrow and wide pore diameters. This rather puzzling result is attributed to the effect of molecular association of alcohol molecules in the solution. [Copyright &y& Elsevier]

The accelerated solvent extraction (ASE) procedure has been examined as a sample preparation method for the HPLC analysis of rutin and isoquercitrin in Sambucus nigra L. The experimental extraction parameters (solvent composition, temperature, operation pressure, and static extraction time) have been optimized in order to receive the best recovery of both analytes from the flowers, leaves, and berries of black elder. The ASE recoveries obtained under the optimal extraction conditions were compared with analogous ones obtained by means of the maceration technique. [ABSTRACT FROM AUTHOR]

Siliceous materials with polymer layers formed by crosslinking of polysaccharide–polyimine mixtures have been evaluated in terms of their acid–base properties and surface charge densities. It was demonstrated that in the investigated pH region (2

The paper presents the results of calorimetric measurements and surface excess adsorption isotherms for n-butanol adsorption from n-hexane on a series of controlled porosity glasses characterized by different mean pore diameters. It is demonstrated that, in the region of very low alcohol concentration in solution, the heat of adsorption exhibits sharp maximum, independently of the pore diameter of adsorbent. This rather puzzling result is explained by the heterogeneity of the surface and the effects of molecular association of alcohol molecules in the solution. A simple theoretical model that supports our predictions is presented. [Copyright &y& Elsevier]

Biological properties of menaquinone-7, one of the vitamin K2 vitamers (K2MK-7), both those proven and those that remain to be investigated, arouse extensive interest that goes beyond the strictly scientific framework. The most important of them is the prevention of age-related diseases, considering that we live in the times identified as the era of aging societies and many people are exposed to the vitamin K2MK-7 deficiency. Therefore, an effective analytical protocol that can be adopted as a diagnostic and preventive analytics tool is needed. Herein, a simple sample preparation method followed by the liquid chromatography-tandem mass spectrometry-based method (LC-MS/MS), was used for the selective and sensitive determination of K2MK-7 in serum samples. Under the optimized conditions, using 500 µL of serum and the same amount of n-hexane, the reproducibility and the accuracy were obtained in the ranges of 89–97% and 86–110%, respectively, and the limit of detection value was 0.01 ng/mL. This method was used for the routine analysis. Statistical interpretation of the data from 518 samples obtained during 2 years of practice allowed for obtaining information on the content and distribution of K2MK-7 in the Polish population, broken down by the sex and age groups. [ABSTRACT FROM AUTHOR]

Highlights • The transformation of curcumin during its extraction in different systems. • The influence of extraction method on curcumin transformation was examined. • The influence of extractant type and pH on curcumin transformation was examined. • Formation of hydroxy and alkoxy adducts of different curcumin isomers. • MS2, HRMS and NMR analysis of curcumin transformation products. Abstract Curcumin is a phenolic compound produced by some plants, among which Curcuma longa is the reachest in this principal curcuminoid. Curcumin is known from its lability, however, the structural curcumin transformations and the formation of hydroxy and alkoxy adducts has not been reported yet. The formation of the mentioned derivatives is favoured by an alkaline environment. The presented results are important both from the analytical and food processing point of view as curcumin transformation products can be mistakenly treated as new components naturally present in turmeric, while in fact they may be formed during food products preparation, causing consumer misinformation about their bioactivity. In this context, an attempt has been made to investigate this problem. The present paper shows that curcumin easily transforms into ketonic/enolic structural isomers and forms adducts with water and alcohols. All structures of these compounds were confirmed by MS n , HRMS and partly also by NMR data. [ABSTRACT FROM AUTHOR]

In this article, we have presented the development and validation of a rapid and sensitive reversed-phase liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for the determination of vincristine (VCR) in patient serum samples. Chromatographic separation was achieved on a Kinetex® (Singapore) column using a mobile phase consisting of 25 mM acetic acid and 0.3% formic acid (A) and methanol (B) in a gradient elution mode at a flow rate of 0.3 mL/min. The VCR and internal standard (vinblastine) were monitored using the multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantification (LLOQ) was 0.67 ng/mL, and the upper limit of quantification (ULOQ) was 250 ng/mL for VCR. The calculated values of LOD and LOQ for VCR were 0.075 and 0.228 ng/mL, respectively. The calibration curve was linear over the VCR concentration range of 1.0–250 ng/mL in serum. The intra- and inter-day precision and precision were within the generally accepted criteria for the bioanalytical method (<15%). The method was successfully applied to the analysis of serum samples in clinical practice. [ABSTRACT FROM AUTHOR]

Abstract: The influence of different Purge Times on the effectiveness of Pressurized Liquid Extraction (PLE) of volatile oil components from cypress plant matrix (Cupressus sempervirens) was investigated, applying solvents of diverse extraction efficiencies. The obtained results show the decrease of the mass yields of essential oil components as a result of increased Purge Time. The loss of extracted components depends on the extrahent type – the greatest mass yield loss occurred in the case of non-polar solvents, whereas the smallest was found in polar extracts. Comparisons of the PLE method with Sea Sand Disruption Method (SSDM), Matrix Solid-Phase Dispersion Method (MSPD) and Steam Distillation (SD) were performed to assess the method''s accuracy. Independent of the solvent and Purge Time applied in the PLE process, the total mass yield was lower than the one obtained for simple, short and relatively cheap low-temperature matrix disruption procedures – MSPD and SSDM. Thus, in the case of volatile oils analysis, the application of these methods is advisable. [Copyright &y& Elsevier]

Abstract: Essential plants, due to their long presence in human history, their status in culinary arts, their use in medicine and perfume manufacture, belong to frequently examined stock materials in scientific and industrial laboratories. Because of a large number of freshly cut, dried or frozen plant samples requiring the determination of essential oil amount and composition, a fast, safe, simple, efficient and highly automatic sample preparation method is needed. Five sample preparation methods (steam distillation, extraction in the Soxhlet apparatus, supercritical fluid extraction, solid phase microextraction and pressurized liquid extraction) used for the isolation of aroma-active components from Thymus vulgaris L. are compared in the paper. The methods are mainly discussed with regard to the recovery of components which typically exist in essential oil isolated by steam distillation. According to the obtained data, PLE is the most efficient sample preparation method in determining the essential oil from the thyme herb. Although co-extraction of non-volatile ingredients is the main drawback of this method, it is characterized by the highest yield of essential oil components and the shortest extraction time required. Moreover, the relative peak amounts of essential components revealed by PLE are comparable with those obtained by steam distillation, which is recognized as standard sample preparation method for the analysis of essential oils in aromatic plants. [Copyright &y& Elsevier]

We compared the antioxidant activity of serum and plasma samples of a known glutathione content with the activity of glutathione, whilst determining to what extent various stress factors might change the activity of the tested samples. Copper ions and benzene were used as examples of environmental stress factors, and xenobiotics in the form of representatives of various groups of drugs, were used as examples of pharmacological stressors at therapeutic ranges. The activity was assessed by the ABTS, ORAC, FRAP and CUPRAC methods. Glutathione content was measured by the HPLC-FD method. During the experiments, plasma samples were shown to be more resistant to oxidative stress. Moreover, the important role of environmental xenobiotics in oxidative stress was revealed, as well as the differentiated influence of pharmaceutical xenobiotics. Among all pharmaceutical xenobiotics tested, including representatives of antiarrhythmic, antiepileptic, cytostatic and mucolytic drugs, the greatest stress was shown for antiarrhythmic drugs and cytostatics. [Display omitted] • Antioxidant activity (AA) of serum, plasma and glutathione samples was compared. • Differentiated impact of various exogenous stress factors on AA was presented. • The greatest impact of antiarrhythmic and cytostatics drugs was proved. • The highest resistance to stress factors was demonstrated for human plasma. • It was proved that Acethylocysteine evidently promotes the increase of AA. [ABSTRACT FROM AUTHOR]

Analysis of plant material is an important task in chemotaxonomical investigations, in search of plants with pharmacological activity or in standardisation of plant drugs. The choice of optimal conditions for the analysis of plant material and effect of extraction method on the yield of furanocoumarins from Pastinaca sativa fruits were examined. The following extraction methods were used in experiments: exhaustive extraction in Soxhlet apparatus, ultrasonification (USAE) at 25 and 60 °C, microwave-assisted solvent extraction in open and closed system (MASE) and accelerated solvent extraction (ASE). In most cases, the yield of furanocoumarins was highest by use of ASE method as well as by ultrasonification at 60 °C. [Copyright &y& Elsevier]

• It was proposed a detailed method for analysis of 11 compounds considered to be dysbiosis markers. • It involves direct derivatization of compounds in a small volume of urine sample followed by GC–MS/MS. • It is characterized by good linearity, low detection limits, and satisfactory precision and accuracy. • Its usefulness was proved during the analysis of authentic urine samples of children diagnosed with dysbiosis. Dysbiosis is a disorder of the bacterial flora of the human digestive tract. It is usually diagnosed clinically by direct detection of an abnormal pattern of the intestinal microbiota. The intermediate diagnosis based on determining the content of microflora metabolites, considered as chemical markers of this disorder, is still rarely used. This is, among others, due to the variety of properties of compounds recognised as dysbiosis markers and as a consequence, the use of different methods for their analysis. To the best of our knowledge, there is still no analytical procedure that would allow unambiguous determination of all compounds in one procedure. In the present study, we have established a detailed method for the quantitative analysis of hydrocinnamic, citramalic, p-hydroxybenzeneacetic, tartaric, hippuric, 4-hydroxybenzoic, indoxylsulfuric, tricarballylic, 3,4-dihydroxyhydrocinnamic and benzoic acids along with DL-arabitol that employs the direct derivatization of compounds in a small volume of urine sample followed by gas chromatography – tandem mass spectrometry (GC–MS/MS). To show that the optimised method is a useful tool for chemical diagnosis of dysbiosis, it was applied for determination of the dysbiosis markers in the authentic urine samples. [ABSTRACT FROM AUTHOR]