Spectroscopic, Spectrometric and Computational Studies of New Lasalocid Derivatives and Their Complexes with Selected Metal Cations.

A series of five esters of lasalocid with neopentyl alcohol (LasNeo), geraniol (LasGeran), 2-ethylhexanol (LasEtHex), eicosanol (LasEico) and vanillyl alcohol (LasVanil) were synthesized and studied by NMR, FT-IR and ESI-MS. Then, their complexes with lithium, sodium and potassium cations were obtained and examined using FT-IR. The analysis of the products confirmed the synthesis of new esters with good yields. The newly obtained compounds, as well as their complexes with monovalent cations, were proved to be stabilized by a strong system of intramolecular hydrogen bonds. The PM6 semiempirical calculations provided information on the heat of formation (HOF) and permitted the making of visual representations of the structures of the newly synthesized esters and their complexes with the investigated cations. All the computational outcomes were consistent with the spectroscopic data.

New Hydrophilic Derivatives of Lasalocid and Their Complexes with Selected Metal Cations.

Two new esters of lasalocid, that are more hydrophilic, with glucose (LasGlu) and xylitol (LasX), have been synthesized, and their complexation of monovalent cations has been studied by various spectrometric and spectroscopic methods, such as ESI mass spectrometry, 1H, 13C NMR and FT-IR. Analyses of the results confirmed the synthesis of new esters with good yields. In order to carry out further studies, it was necessary to purify them using "flash" liquid chromatography. It was confirmed that the newly obtained molecules, as well as their complexes with lithium, sodium and potassium cations, were stabilized by a strong system of intramolecular hydrogen bonds. It was found that the hydroxyl groups of esters derived from xylitol and glucose were also involved in the complexation of cations. The results of the PM6 semiempirical calculations permitted determination of the heat of formation (HOF), and visualization of the structure of the new esters and their complexes with the cations studied. All computation results are in agreement with the spectroscopic data.

Comparison of the Antioxidant Properties of Green Macroalgae from Diverse European Water Habitats by Use of Several Semi-Quantitative Assays.

Nowadays, algae are becoming more and more popular as a food group rich in nutrients, cosmetic raw materials full of antioxidants or valuable dietary supplements. They are of interest for the industry because they are found almost all over the world, in all climatic zones, both in fresh and salt waters. The aim of this study was to take a broad look at green algae (Chlorophyta) and to show how large the variability of the content of active compounds may depend on the species and the place and time of sample collection. Particular attention was paid to compounds with antioxidant activity, whose simplified profiles were created on the basis of complementary, semi-quantitative methods. Additionally, time-yield extraction optimizations were performed. Three different specimens of Ulva lactuca were compared: from the coastal zone of the Baltic Sea, from the open Baltic Sea area around Bornholm and Ulva spiralis (Ulva lactuca polymorph) from the Atlantic Ocean. The studied algae of the Cladophora genera were three different species of freshwater algae from various habitats: a lake (Cladophora glomerata), a river (Cladophora rivularis) and aquarium farming (Cladophora aegagropila, syn. Aegagropila linnaei). The content of antioxidants and the extraction efficiency varied significantly depending on the species.

Overview of Allelopathic Potential of Lemna minor L. Obtained from a Shallow Eutrophic Lake.

Allelopathy is an interaction that releases allelochemicals (chemicals that act allelopathically) from plants into the environment that can limit or stimulate the development, reproduction, and survival of target organisms and alter the environment. Lemna minor L. contains chemicals that are allelopathic, such as phenolic acids. Chemical compounds contained in L. minor may have a significant impact on the development and the rate of multiplication and lead to stronger competition, which may enhance the allelopathic potential. Allelopathic potential may exist between L. minor and C. glomerata (L) Kütz. because they occupy a similar space in the aquatic ecosystem, have a similar preference for the amount of light, and compete for similar habitat resources. L. minor and C. glomerata can form dense populations on the water surface. Allelopathy can be seen as a wish to dominate one of the plants in the aquatic ecosystem. By creating a place for the development of extensive mats, an interspecific interaction is created and one of the species achieves competitive success. It is most effective as a result of the release of chemicals by macrophytes into the aquatic environment. Therefore, allelopathy plays a significant role in the formation, stabilization, and dynamics of the structure of plant communities.

Phenol-rich alternatives for Rosa x damascena Mill. Efficient phytochemical profiling using different extraction methods and colorimetric assays.

Damask rose is a well-established, abundant source of phytochemicals, as well as economically important essential oil-however, its cultivation is demanding and costly. In this paper, extracts from four raw plant materials-Salvia officinalis, Sambucus nigra, Matricaria chamomilla, Calendula officinalis, known to be rich in phenolic compounds, but also far easier to cultivate-were directly compared to those obtained from Rosa × damascena Mill. By combining diverse extraction methodologies (in a Soxhlet apparatus, ultrawave-assisted and microwave-assisted, using supercritical CO2) and complementary in vitro assays (radical scavenging, iron reducing, Folin-Ciocalteau and Al3+ complexation), it was possible to conveniently approximate and compare the phytochemical portfolios of those diverse plants. By factoring in the crop yields of different species, economically important conclusions can be reached-with pot marigold (C. officinalis) seemingly the most viable substitute for damask rose as a source of phenolics. Fatty acid and microelement analyses were also performed, to further enrich the chemical profiles of plant extracts. The paper also aims to collate and redesign multiple colorimetric assays frequently used while studying plant extracts in vitro, but criticized for their lack of correlation to in vivo activity. We show that they remain a viable tool for direct comparison of extraction methodologies, while highlighting their shortcomings.

Seasonal differences in the content of phenols and pigments in thalli of freshwater Cladophora glomerata and its habitat.

Polyphenols are chemicals that primarily inhibit the growth of various autotrophic organisms. The presence of these metabolites greatly boosts the ecological dominance of eg. Cladophora, which creates large surface mats. The main goal of our work was to quantify the phenol and polyphenols (allelopathic substances) secreted by the macroalgae as a result of exposure to biotic stress caused by competition. The research was carried out on the Cladophora glomerata biomass collected from two freshwater ecosystems located in Wielkopolska Region (Poland, Fig. 1): Oporzynskie Lake (N52° 55', E 17° 9') and Nielba River (N52˚48', E 17° 12'). Seasonal variability (May-October 2015) in the properties of C. glomerata mats in the river and lake ecosystem was also analyzed in relation to the physicochemical parameters of water. In addition, the content of pigments in the analyzed biomass was determined during the appearance of algae mats in water reservoirs. Biomass extraction was performed to determine the phenolic and carotenoid contents (chlorophyll and carotenoids) by using two extraction methods: microwave-assisted extraction (MAE) and supercritical fluid extraction (SFE). After isolation of the phenols from the thalli (mats) and the habitat, they were analyzed using the Folin-Ciocalteu method with some modifications, while the pigment content (chlorophyll and carotenoids) was evaluated by the spectrophotometric method Liechtenthaler (1987) with some variations. Analysis of the content of these components in algae extracts indicates that the tendency of changes in their contents was similar or the same. Growth and decrease of phenolic content (Cladophora T MAE and Cladophora T SFE) and pigments (MAE chlorophyll, SFE and MAE carotenoids) at the same time were independent of the insulation method used. The mats formed by C. glomerata on the surface of Lake Oporzynskie were more stable and larger surface area than those on the Nielba River, which could explain differences in polyphenol concentrations in these two aquatic ecosystems. The results suggest a reduction in the secretion of phenolic compounds with an aging population of algae.

Disiloxanes and Functionalized Silica Gels: One Route, Two Complementary Outcomes-Guanidinium and Pyridinium Ion-Exchangers.

Five novel disiloxane compounds comprising guanidinium and pyridinium moieties were obtained with high yields and purity. The verified synthetic pathways were then applied for modification of pre-functionalized silica gel, producing materials with the analogous organic side-chains. These halide-containing compounds and materials were then compared as to their ion-exchange properties: two disiloxanes proved to be effective in leaching different anions (nitrate, benzoate and ascorbate) from solid to organic phase, and pyridinium-functionalized silica gels showed selectivity towards perchlorate ion, removing it from methanolic solutions with preference to other singly charged anions. The results presented demonstrate that both compounds and materials containing silicon-carbon bonds can be produced using the same methodology, but offer strikingly different application opportunities. Comparison of their properties provides additional insight into the binding mode of different anions and hints at how the transition from a flexible siloxane bridge to immobilization on solid surface influences anion-binding selectivity. Additionally, one of the siloxane dipodands was found to form a crystalline and poorly soluble nitrate salt (1.316 g/L, water), although it was miscible with a wide range of solvents as a hydrochloride. A possible explanation is given with the help of semi-empirical calculations. A simple, time- and cost-efficient automated potentiometric titration methodology was used as a viable analytical tool for studying ion-exchange processes for both compounds and materials, in addition to standard NMR, FT-IR and ESI-MS methods.

Influence of stage of lactation and year season on composition of mares' colostrum and milk and method and time of storage on vitamin C content in mares' milk.

BACKGROUND: Mares' milk is becoming increasingly popular in Western Europe. This study was thus aimed at investigating the impact of stage of lactation and season on chemical composition, somatic cell count and some physicochemical parameters of mares' colostrum and milk, and at developing a method for the determination of vitamin C (ascorbic acid) in mares' milk and to determine its content in fresh and stored milk. RESULTS: The analysis conducted showed an effect of the stage of lactation on contents of selected chemical components and physicochemical parameters of mares' milk. In successive lactation periods levels of fat, cholesterol, energy value, citric acid and titratable acidity decreased, whereas levels of lactose and vitamin C, as well as the freezing point, increased. Analysis showed that milk produced in autumn (September, October, November) had a higher freezing point and lower concentrations of total solids, protein, fat, cholesterol, citric acid and energy value in comparison to milk produced in summer (June, July, August). Mares' milk was characterised by low somatic cell count throughout lactation. In terms of vitamin C stability the most advantageous method of milk storage was 6-month storage of lyophilised milk. CONCLUSION: In general, the results confirmed that mares' milk is a raw material with a unique chemical composition different from that produced by other farm animals.

17O NMR studies of substituted 1,3,4-oxadiazoles.

Three series of substituted 1,3,4-oxadiazoles were studied by (17)O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values.

The diffusion NMR studies of crown ethers-cyclodextrin complexation process.

Formation of complexes between crown ethers and cyclodextrins has been studied using diffusion measurements. The structures of the complexes have been proposed on the basis of the theoretical calculations and the results obtained. Relation between the structural parameters (rings' diameter and symmetry) and the tendency of molecules' interactions are discussed.

(E)-4-alkoxycarbonylalkylthiochalcones: differentiation of isomeric derivatives by electron ionization mass spectrometry.

The principal fragmentation pathways of the molecular ions of 18 new (E)-4-alkoxycarbonylalkylthiochalcones have been investigated. It has been shown that the data derived from electron ionization mass spectra (the relative abundance of the fragment ions and values of coefficients micro) can be used to differentiate the isomers. The fragmentation rules deduced here could help in the characterization of other chalcones of these types.

Multinuclear NMR and FTIR studies of new polyoxaalkyl esters of lasalocid and their complexes with lithium and sodium cations.

Three new polyoxaalkyl esters of lasalocid are synthesized. Their ability to form complexes with Li(+) and Na(+) cations is studied using multinuclear NMR methods, FTIR spectroscopy in the middle and far IR regions, and mass spectrometry. It is found that lasalocid esters form only 1:1 complexes with the metal cations. The results of the NMR study in pyridine show that the polyoxaalkyl chain of the ester does not influence the complex formation of the lasalocid part of the esters. The reason for this is the competition of the pyridine molecules in the complexation process of metal cations. In chloroform the properties of the complex formation have changed and the oxaalkyl chain plays an important role within the complexation process, as demonstrated by the dependence of the respective continuous absorptions in the far IR region on the length of the oxaalkyl chain (i.e., on the number of the oxygen atoms in the chain). The modifications of the lasalocid molecule influences the complexation of the metal cation and probably the interactions with the membrane. An increase in antibiotic activity is found as a consequence of these changed interactions.