Identification of potential sources of thymoquinone and related compounds in Asteraceae, Cupressaceae, Lamiaceae, and Ranunculaceae families

In this study, forty-seven plant species belonging to seven families were analysed by GC and GC-MS for the contents of pharmacologically effective quinones: dithymoquinone (DTQ), thymohydroquinone (THQ), and thymoquinone (TQ). The results showed that detectable amounts (??1 mg kg^?1) of at least one of these compounds have been found in three species of both Monarda (M. didyma, M. media, and M. menthifolia) and Thymus (T. pulegioides, T. serpyllum, and T. vulgaris) genera, two Satureja (S. hortensis and S. montana) species, and in single representatives of Eupatorium (E. cannabinum), Juniperus (J. communis), and Nigella (N. sativa) genera. The maximum contents of THQ and TQ were found in M. media aerial parts and M. didyma inflorescences (2674 and 3564 mg kg^?1 of dried weight, respectively) in amounts significantly exceeding their maximum contents in N. sativa seeds (THQ = 530 mg kg^?1 and TQ = 1881 mg kg^?1), which are generally considered as the main natural source of both of these compounds. As a conclusion, M. didyma (bergamot) and M. media (purple bergamot) can be recommended as new prospective natural sources of THQ and TQ for pharmaceutical or food industries.      

Solution and solid-state studies of a new supramolecular proton transfer salt and its VO<Subscript>2</Subscript> complex constructed with chelidamic acid and 3,4-diaminopyridine

The proton transfer compound (Hdap)(chelH)·2H₂O (1) and its related anionic complex (Hdap) [VO₂(chel)] (2), where chelH₂ = 4-hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid) and dap = 3,4-diaminopyridine, were synthesized and characterized by elemental analysis, spectroscopy (IR, UV–Vis), thermal (TG/DTG) analysis and single-crystal X-ray diffraction. Compound 1 resulted from proton transfer between chelH₂ and dap in aqueous solution. In 1, two carboxylic acids of chelH₂ were deprotonated and the protons transferred to the nitrogen atoms of one chelidamate anion and one dap moiety. Compound 2 resulted from complexation of 1 and vanadyl sulfate. In the crystal structure of 2, the metal ion is five coordinated by one tridentate ligand (chel)^2? and two O^2? anions, with (Hdap)⁺ as a counter cation. In both structures, a complicated hydrogen-bonding network accompanied with π–π, C–O···π and C–H···π stacking interactions leads to formation of a 3D supramolecular network. In the following, solution studies have been performed by means of pH potentiometric titrations method as a power technique. This method was used for determination of protonation constants of chelH₂ and dap in their probable protonated forms and for calculation of equilibrium constants for the chelH₂–dap proton transfer system and the stoichiometry and stability constants of binary and ternary complexes of this system with VO²⁺ ion in aqueous solution. The stoichiometries of the most complex species in solution were compared with the corresponding crystalline complexes in the solid state.     

Silver-ion reversed-phase comprehensive two-dimensional liquid chromatography combined with mass spectrometric detection in lipidic food analysis

The triacylglycerol (TAG) profiles present in real world lipidic samples are usually quite complex and, as such, monodimensional high-performance liquid chromatographic (HPLC) techniques are inadequate when challenged with such matrices. In this respect, the complementary use of silver-ion (Ag) and non-aqueous (NA) reversed-phase (RP) HPLC can be exploited if thorough TAG separations are required. The present investigation reports the employment of a newly developed comprehensive LC (LC x LC) system, based on the different separation mechanisms of the aforementioned techniques, and applied to a rice oil sample. The approach was successful in the separation of a high number of solutes, otherwise unachievable through monodimensional LC. Furthermore, the use of atmospheric pressure chemical ionization mass spectrometry (APCI-MS), as detection system, provided a third analytical dimension boosting the identification power of the comprehensive chromatographic method.     

Selective transport of ATP across a phospholipid bilayer by a molecular umbrella

Acylation of each primary group of spermidine with cholic acid, followed by acylation of the secondary amino group using an activated form of Nalpha,Ndelta,Nomega-tri-CBZ-l-arginine, and subsequent hydrogenolysis, afforded a conjugate (i.e., 1) which readily transports adenosine 5-triphosphate, but not glutathione, across phospholipid bilayers made from 1-palmitoyl-2-oleyol-sn-glycero-3-phosphocholine and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol.     

Glued Langmuir-Blodgett bilayers from porous versus nonporous surfactants

Poly(4-styrenesulfonate) (PSS) has been used to ionically cross-link (glue together) single Langmuir-Blodgett bilayers derived from 1,2,4,5-tetrakis[N,N-dimethyl-N-(1-hexadecyl)-ammoniummethyl]benzene (2a) and tris(N,N-dimethyl-N-hexadecylammoniummethyl)mesitylene (3). The resulting films are of high quality as judged by He/N2 permeation selectivities of ca. 100. Such selectivity is well in excess of the Knudsen diffusion limit of 2.6 and approaches that which has been found for glued bilayers of 5,11,17,23,29,35-hexakis[(N,N,N-trimethylamonium)-N-methyl-37,38,39,40,41,42-hexakis-n-hexamedecyloxy-calix[6]arene hexachloride (1). The significance of these findings to LB technology, in general, is briefly discussed.     

Endomorphism monoids of bands

Communicated by Boris M. Schein