Polycommunin A, a dihydrocinnamoyl bibenzyl isolated from the moss Polýtrichum commúne, and its antioxidant activity.

A novel polyphenolic compound named Polycommunin A (1) was discovered in the aerial part of the common haircap moss (Polýtrichum commune) widely spread in boreal and temperate climate zones. Aqueous ethanol and extraction of the plant material with further isolation of polyphenolic fraction and preparative HPLC separation allowed obtaining individual compound and identifying it as dimeric dihydrocinnamoyl bibenzyl by NMR spectroscopy and high-resolution tandem mass spectrometry. Polycommunin A demonstrated high in vitro antioxidant activity determined by FRAP and PCL assays and comparable to that of Trolox and Quercetin.

Analysis of Softwood Lignans by Comprehensive Two-Dimensional Liquid Chromatography.

Lignans constitute a large group of phenolic plant secondary metabolites possessing high bioactivity. Their accurate determination in plant extracts with a complex chemical composition is challenging and requires advanced separation techniques. In the present study, a new approach to the determination of lignans in coniferous knotwood extracts as the promising industrial-scale source of such compounds based on comprehensive two-dimensional liquid chromatography separation and UV spectrophotometric detection is proposed. First and second-dimension column screening showed that the best results can be obtained using a combination of non-polar and polar hydroxy group embedded octadecyl stationary phases with moderate (~40%) "orthogonality". The optimization of LC × LC separation conditions allowed for the development of a new method for the quantification of the five lignans (secoisolariciresinol, matairesinol, pinoresinol, 7-hydroxymatairesinol, and nortrachelogenin) in knotwood extracts with limits of quantification in the range of 0.27-0.95 mg L-1 and a linear concentration range covering at least two orders of magnitude. Testing the developed method on coniferous (larch, fir, spruce, and pine) knotwood extracts demonstrated the high selectivity of the analysis and the advantages of LC × LC in the separation and accurate quantification of the compounds co-eluting in one-dimensional HPLC.

Fractionation of Arctic Brown Algae (Fucus vesiculosus) Biomass Using 1-Butyl-3-methylimidazolium-Based Ionic Liquids.

Arctic brown algae are considered a promising industrial-scale source of bioactive sub-stances as polysaccharides, polyphenols, and low-molecular secondary metabolites. Conventional technologies for their processing are focused mainly on the isolation of polysaccharides and involve the use of hazardous solvents. In the present study a "green" approach to the fractionation of brown algae biomass based on the dissolution in ionic liquids (ILs) with 1-butil-3-methylimidazolium (bmim) cation with further sequential precipitation of polysaccharides and polyphenols with acetone and water, respectively, is proposed. The effects of IL cation nature, temperature, and treatment duration on the dissolution of bladderwrack (Fucus vesiculosus), yields of the fractions, and their chemical composition were studied involving FTIR and NMR spectroscopy, as well as size-exclusion chromatography and monosaccharide analysis. It was shown that the use of bmim acetate ensures almost complete dissolution of plant material after 24 h treatment at 150 °C and separate isolation of the polysaccharide mixture (alginates, cellulose, and fucoidan) and polyphenols (phlorotannins) with the yields of ~40 and ~10%, respectively. The near-quantitative extraction of polyphenolic fraction with the weight-average molecular mass of 10-20 kDa can be achieved even under mild conditions (80-100 °C). Efficient isolation of polysaccharides requires harsh conditions. Higher temperatures contribute to an increase in fucoidan content in the polysaccharide fraction.

Comprehensive Characterization of Secondary Metabolites in Fruits and Leaves of Cloudberry (Rubus chamaemorus L.).

Cloudberry (Rubus chamaemorus L.) is a circumpolar boreal plant rich in bioactive compounds and is widely used in food and in folk medicine. In this study, a combination of two-dimensional NMR spectroscopy and liquid chromatography-high-resolution mass spectrometry was used for the comprehensive characterization of secondary metabolites in cloudberry lipophilic and hydrophilic extracts. Special attention was paid to the leaf extractives, which are highly enriched in polyphenolic compounds, the content of which reaches 19% in the extract (in gallic acid equivalent). The chemical composition of the polyphenolic fraction is represented mainly by the glycosylated derivatives of flavonoids, hydroxycinnamic (primarily caffeic), gallic (including the structure of galloyl ascorbate) and ellagic acids, catechin, and procyanidins. The contents of aglycones in the polyphenolic fraction were 64 and 100 mg g-1 for flavonoids and hydroxycinnamic acids, respectively, while the content of free caffeic acid was 1.2 mg g-1. This determines the exceptionally high antioxidant activity of this fraction (750 mg g-1 in gallic acid equivalent) and the ability to scavenge superoxide anion radicals, which is 60% higher than that of Trolox. The lower polar fractions consist mainly of glycolipids, which include polyunsaturated linolenic acid (18:3), pentacyclic triterpenic acids, carotenoid lutein, and chlorophyll derivatives, among which pheophytin a dominates. Along with the availability, the high antioxidant and biological activities of cloudberry leaf extracts make them a promising source of food additives, cosmetics, and pharmaceuticals.

Determination of Pentacyclic Triterpenoids in Plant Biomass by Porous Graphitic Carbon Liquid Chromatography-Tandem Mass Spectrometry.

Pentacyclic triterpenoids (PCTs), which possess a number of bioactive properties, are considered one of the most important classes of secondary plant metabolites. Their chromatographic determination in plant biomass is complicated by the need to separate a large number of structurally similar compounds belonging to several classes that differ greatly in polarity (monools, diols, and triterpenic acids). This study proposes a rapid, sensitive, and low-cost method for the simultaneous quantification of ten PCTs (3ß-taraxerol, lupeol, ß-amyrin, α-amyrin, betulin, erythrodiol, uvaol, betulinic, oleanolic, and ursolic acids) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using porous graphitic carbon (Hypercarb) as a stationary phase capable of hydrophobic retention and specific interactions with analytes. Revealing the effects of the mobile phase composition, pH, ionic strength, and column temperature on retention and selection of chromatographic conditions on this basis allowed for the effective separation of all target analytes within 8 min in gradient elution mode and attaining limits of detection in the range of 4-104 µg L-1. The developed method was fully validated and successfully tested in the determination of PCTs in common haircap (Polytrichum commune) and prairie sphagnum (Sphagnum palustre) mosses, and fireweed (Chamaenerion angustifolium) stems and leaves.

New Oligomeric Dihydrochalcones in the Moss Polytrichum commune: Identification, Isolation, and Antioxidant Activity.

One of the most widespread representatives of mosses in the temperate and boreal latitudes of the Northern Hemisphere is common haircap (Polytrichum commune), which is known as the largest moss in the world and widely used in traditional herbal medicine. Polyphenolic compounds constitute one of the most important groups of biologically active secondary metabolites of P. commune, however, the available information on their chemical composition is still incomplete and contradictory. In the present study, a group of dihydrochalcone polyphenolic derivatives that were not previously found in mosses was isolated from P. commune biomass using pressurized liquid extraction with aqueous acetone. The combination of two-dimensional NMR spectroscopy and high-performance liquid chromatography-high-resolution mass spectrometry allowed for identifying them as 3-hydroxyphloretin oligomers formed through a carbon-carbon bond between phloroglucinol and pyrocatechol moieties ("head-to-tail" coupling), with a polymerization degree of 2-5. The individual compounds isolated by preparative reverse-phase HPLC had a purity of 71 to 97% and demonstrated high radical scavenging activity (17.5-42.5% with respect to Trolox) determined by the photochemiluminescence method. Along with the low toxicity predicted by QSAR/QSTR algorithms, this makes 3-hydroxyphloretin oligomers a promising source for the production of biologically active food additives and pharmaceuticals.

Rapid determination of phthalates in paper products by supercritical fluid chromatography/tandem mass spectrometry.

Phthalic acid esters are widely used as components of industrial and consumer products including paper and cardboard packaging materials in contact with food or human skin. Being endocrine-disrupting chemicals, phthalic acid esters have a negative effect on human health and must be controlled in pulp and paper products. In the present study, supercritical fluid chromatography-tandem mass spectrometry in combination with pressurized liquid extraction was proposed for phthalic acid esters determination in such objects. Octadecyl stationary phase with non-endcapped silanol groups ensured rapid (4 min) separation of the 10 priority phthalic acid esters in isocratic elution mode and allowed for effective elimination of interferences from the trace impurities of phthalic acid esters in the mobile phase. The attained limits of quantitation are in the range of 0.7-10 µg/L in extracts and 0.02-0.3 µg/g in paper and cardboard samples. The developed method is distinguished by analysis rapidity, easy sample preparation procedure, high selectivity, low susceptibility to mobile phase contamination with analytes, low cost, and environmental friendliness due to the use of carbon dioxide as a main component of the mobile phase. The method was successfully tested on real samples of toilet paper and food packaging paper and cardboard in which eight analytes were found at the levels of 0.03-43.5 µg/g.

Comparative study of four Yucca species by 2D-NMR and LC-MS.

The present study was conducted to compare leaf extracts of Y. gloriosa, Y. treculeana, Y. filamentosa and Y. aloifolia. Plant extracts were obtained by sequential extraction with 50% and 100% methanol using the pressurized liquid extraction method. General comparative analysis of Yucca extracts was performed by 2 D-NMR. The presence of various biologically active components in the extracts was shown, among which steroid saponins predominate. The use of LC-MS and LC-HRMS methods with electrospray ionization made it possible to conduct a comparative analysis of Yucca steroidal saponins. The 33 steroidal saponins of various structures were found. The presence of three characteristic saponins in all Yucca species was shown: yuccaloeside C, yuccaloeside E and yuccaloeside B. The results obtained can be used to control the quality of plant materials and products.

Rapid Simultaneous Quantification of 1-Formyl-2,2-Dimethylhydrazine and Dimethylurea Isomers in Environmental Samples by Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

When released to the environment, the rocket fuel unsymmetrical dimethylhydrazine (UDMH) undergoes oxidative transformations, resulting in the formation of an extremely large number of nitrogen-containing transformation products, including isomeric compounds which are difficult to discriminate by common chromatography techniques. In the present work, supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) was proposed for resolving the problem of fast separation and simultaneous quantification of 1-formyl-2,2-dimethylhydrazine (FADMH) as one of the major UDMH transformation products, and its isomers-1,1-dimethylurea (UDMU) and 1,2-dimethylurea (SDMU). 2-Ethylpyridine stationary phase provided baseline separation of analytes in 1.5 min without the distortion of the chromatographic peaks. Optimization of SFC separation and MS/MS detection conditions allowed for the development of rapid, sensitive, and "green" method for the simultaneous determination of FADMH, UDMU, and SDMU in environmental samples with LOQs of 1-10 µg L-1 and linear range covering three orders of magnitude. The method was validated and successfully tested on the real extracts of peaty and sandy soils polluted with rocket fuel and UDMH oxidation products. It was shown that both UDMU and SDMU are formed in noticeable amounts during UDMH oxidation. Despite relatively low toxicity, UDMU can be considered one of the major UDMH transformation products and a potential marker of soil pollution with toxic rocket fuel.

Supercritical Fluid Chromatography-Tandem Mass Spectrometry for Rapid Quantification of Pentacyclic Triterpenoids in Plant Extracts.

Pentacyclic triterpenoids (PCTs) are a widely distributed class of plant secondary metabolites. These compounds have high bioactive properties, primarily antitumor and antioxidant activity. In this study, a method was developed for the quantitative analysis of pentacyclic triterpenoids in plants using supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS). Separation of ten major PCTs (friedelin, lupeol, ß-amyrin, α-amyrin, betulin, erythrodiol, uvaol, betulinic, oleanolic and ursolic acids) was studied on six silica-based reversed stationary phases. The best results (7 min analysis time in isocratic elution mode) were achieved on an HSS C18 SB stationary phase using carbon dioxide-isopropanol (8%) mobile phase providing decisive contribution of polar interactions to the retention of analytes. It was shown that the use of atmospheric pressure chemical ionization (APCI) is preferred over atmospheric pressure photoionization (APPI). The combination of SFC with APCI-MS/MS mass spectrometry made it possible to achieve the limits of quantification in plant extracts in the range of 2.3-20 µg·L-1. The developed method was validated and tested in the analyses of birch outer layer (Betula pendula) bark, and licorice (Glycyrrhiza glabra) root, as well as lingonberry (Vaccinium vitis-idaea), cranberry (Vaccinium oxycoccos), apple (Malus domestica "Golden Delicious" and Malus domestica "Red Delicious") peels.

Analysis of the functional group composition of the spruce and birch phloem lignin.

In this article, the functional group composition of the spruce (Pícea ábies) and birch (Bétula péndula) phloem lignin is described. The features of the chemical structure were studied by analyzing dioxane lignin using the elemental analysis, UV-Vis, FT-IR, and 1D NMR spectroscopy. For comparison, samples of xylem dioxane lignin isolated from the corresponding wood species were also analyzed. FT-IR spectroscopy data suggest that the lignins of birch phloem and xylem are similar in chemical structure. However, there are differences in absorption bands in the spectra of spruce dioxane lignin, which indicate the opposite. Quantitative analysis of the functional group composition was performed using 13C and 31P NMR data. It was found that free phenolic hydroxyl groups of catechol and p-hydroxyphenyl types are dominated in the composition of spruce phloem lignin. Birch phloem lignin has a qualitative and quantitative composition of functional groups characteristic of hardwood lignins. However, the content of G-units is greater than S-units, in contrast to the birch xylem lignin, where S-units predominate. The revealed differences are relevant from the point of view of plant physiology. The practical significance of the study is connected with understanding the reactivity of lignins when considering the chemical processing of tree bark.

Screening and semi-quantitative determination of pentacyclic triterpenoids in plants by liquid chromatography-tandem mass spectrometry in precursor ion scan mode.

INTRODUCTION: Pentacyclic triterpenoids (PCTs) are secondary plant metabolites. They are of exceptional interest as biologically active substances and raw materials for a wide range of medications. Thus, the development of a methodology for rapid screening of PCTs in plant biomass is an important task. OBJECTIVE: The goal of this work was to develop an approach for simultaneous screening and semi-quantitative determination of PCTs in plant tissues by liquid chromatography-tandem mass spectrometry with a precursor ion scan (PrecIS). MATERIALS AND METHODS: Pressurised liquid extraction (PLE) with methanol was used for the isolation of PCTs from plant biomass. Screening and semi-quantitative determination of PCTs in the obtained extracts were carried out by reversed phase high-performance liquid chromatography-tandem mass spectrometry in a PrecIS mode. RESULTS: The product ion at m/z 95 with collision energy of 40 V was used as a diagnostic ion to identify PCTs by the PrecIS mode. In plant materials, 26 PCTs and their derivatives, such as PCTs esters and glycosides, were detected and identified. Calculation of the relative response factor for nine available PCTs showed that using a betulin calibration curve allows us to estimate the semi-quantitative content of PCTs and their derivatives in plant PLE extracts. CONCLUSION: The developed approach can be applied for simultaneous untargeted screening and semi-quantitative determination of PCTs and their derivatives in various plants at sub-parts per million levels.

Data on the spatial distribution of 1,1-dimethylhydrazine and its transformation products in peat bog soil of rocket stage fall site in Russian North.

The data set covers the results of a study of 96 samples of peat bog soil from the fall place of the first stage of the Cyclone-3 launch vehicle contained unburned toxic rocket fuel 1,1-dimethylhydrazine (UDMH) in the European North of Russia. Soil samples were taken during a helicopter expedition to the "Koida" fall region of Plesetsk Cosmodrome operation zone in October 2015 at different distances from the center of the fall site and from different soil horizons. Samples were analyzed by liquid chromatography with amperometric detection and gas chromatography - tandem mass spectrometry. The contents of UDMH and the ten most important products of its transformations (methylhydrazine, hydrazine, 1,1,4,4-tetramethyltetrazene, formaldehyde, acetaldehyde and furaldehyde N,N-dimethylhydrazones, 1-formyl-2,2-dimethylhydrazine, N,N-dimethylformamide, N-nitrosodimethylamine, and 1-methyl-1H-1,2,4-triazole) were determined. The obtained data reflect the spatial distribution, migration and transformation of UDMH in the fall places of rocket stages under conditions of subarctic which is discussed in related research article "Migration and transformation of 1,1-dimethylhydrazine in peat bog soil of rocket stage fall site in Russian North" [1]. They can be further used for understanding the UDMH transformation pathways in soils rich in organic matter and assessment of environmental impact of space rocket activities in high latitudes.

Migration and transformation of 1,1-dimethylhydrazine in peat bog soil of rocket stage fall site in Russian North.

An ingress of highly toxic rocket fuel 1,1-dimethylhydrazine (UDMH) and its transformation products into environment represents a serious negative impact on the ecosystem, as well as human health. The present research demonstrates the first data on the spatial distribution and quantification of UDMH and its main transformation products (methylhydrazine, hydrazine, 1,1,4,4-tetramethyltetrazene, formaldehyde, acetaldehyde and furaldehyde N,N-dimethylhydrazones, 1-formyl-2,2-dimethylhydrazine, N,N-dimethylformamide, N-nitrosodimethylamine, and 1-methyl-1H-1,2,4-triazole) in the peat bog soil of the fall site in subarctic region. One hundred samples of peat bog soil and one sample of surface water were analyzed by the developed earlier methodology. The considerable amounts of UDMH and most of its transformation products were found at distances of not >10 m from the center of the fall site. The maximum concentration of UDMH was found near the center, where maximal permissible concentration (MPC) was exceeded 2400-fold. The greatest pollution was observed in the surface soil layer, while methylhydrazine, 1-methyl-1H-1,2,4-triazole, 1-formyl-2,2-dimethylhydrazine, formaldehyde and acetaldehyde N,N-dimethylhydrazones, and N,N-dimethylformamide were the major UDMH transformation products. With increasing distance from the center, the composition of the transformation products changes in favor of the last three compounds. Formaldehyde N,N-dimethylhydrazone and N,N-dimethylformamide are present in all soil samples and can be considered as reliable markers of contamination with rocket fuel. The surface water of the peat bog contained four UDMH transformation products in considerable concentrations, including extremely toxic N-nitrosodimethylamine. The processes of migration and transformation of UDMH in peat bog soil differ considerably from those in sandy soils. This is due to cold climate of subarctic zone, the reducing environment of peat bog, and strong binding of hydrazines to organic matter of peat, which prevents migration of pollutants and contributes to the long-term maintenance of high levels of soil pollution.

Rapid simultaneous determination of pentacyclic triterpenoids by mixed-mode liquid chromatography-tandem mass spectrometry.

Pentacyclic triterpenoids (PCTs) possess high biological activity, including antitumor, anti-inflammatory, antiviral and hepatoprotective properties and are widespread in a plant biomass. Due to significant differences in polarity and other physicochemical properties, the simultaneous determination of different classes of PCTs by the methods of reversed phase liquid chromatography is difficult. In the present study, we proposed a new approach to chromatographic separation of such compounds based on the use of a stationary phase with a mixed retention mechanism combining hydrophobic, weak anion exchange and hydrophilic interactions. The use of the Acclaim Mixed-Mode WAX-1 column and tuning the selectivity by changing the contributions of different types of analyte-stationary phase interactions allowed the separation of 10 PCTs (betulin, erythrodiol, uvaol, friedelin, lupeol, ß-amyrin, α-amyrin, betulinic, oleanolic and ursolic acids) belonging to four different classes (monools, diols, ketones and triterpenic acids) during 7.5 min in isocratic elution mode. The combination of this approach with atmospheric pressure chemical ionization tandem mass spectrometric detection and pressurized liquid extraction of analytes with methanol allowed to develop a rapid, accurate and highly sensitive method for analyzing PCTs in plant tissues with a total duration of the analytical cycle (including sample preparation steps) of not more than 40 min. It provides the detection limits in plant biomass extracts of 3-12 µg L-1 (44 µg L-1 for friedelin). The developed method was validated and successfully tested in the analyses of real birch bark and lingonberry peels.

Evaluation of temperature and pressure effects on retention in supercritical fluid chromatography on polar stationary phases.

Four polar stationary phases (ethylene-bridged hybrid silica, cyanopropyl, 2-ethylpyridine, and zwitterionic sulfobetaine) have been characterized in supercritical fluid chromatography (SFC) by linear free energy relationships (LFER) method with an extended set of Abraham's descriptors. Temperature (25-55 °C) and pressure (110-180 bar) effects on analyte retention, separation selectivity and LFER-coefficients of chromatographic systems have been studied using the 89 test compounds of various chemical classes and carbon dioxide - methanol (9:1 v/v) binary solvent as a mobile phase. It was found that for the selected stationary phases temperature and pressure had only moderate effects on selectivity. The retention times of all analytes decrease, as can be expected, if the pressure rises at the isothermal conditions due to the increase of the fluid density and its eluting power. The effect of temperature on retention is complicated and depends both on the chemical class of analyzed compounds and the stationary phase type. Temperature and pressure variations lead to small changes in the LFER-coefficients, and general trends observed do not depend much on the stationary phase type. It may be difficult to interpret the LFER-analysis results because of the evident, more significant chromatographic phenomena.