Comparison of the structure of (E)-2-(2-benzylidenehydrazinylidene)quinoxaline with those of its chloro- and bromobenzylidene analogues.

(E)-2-(2-Benzylidenehydrazinylidene)quinoxaline, C15H12N4, crystallized with two molecules in the asymmetric unit. The structures of six halogen derivatives of this compound were also investigated: (E)-2-[2-(2-chlorobenzylidene)hydrazinylidene]quinoxaline, C15H11ClN4; (E)-2-[2-(3-chlorobenzylidene)hydrazinylidene]quinoxaline, C15H11ClN4; (E)-2-[2-(4-chlorobenzylidene)hydrazinylidene]quinoxaline, C15H11ClN4; (E)-2-[2-(2-bromobenzylidene)hydrazinylidene]quinoxaline, C15H11BrN4; (E)-2-[2-(3-bromobenzylidene)hydrazinylidene]quinoxaline, C15H11BrN4; (E)-2-[2-(4-bromobenzylidene)hydrazinylidene]quinoxaline, C15H11BrN4. The 3-Cl and 3-Br compounds are isomorphous, as are the 4-Cl and 4-Br compounds. In all of these compounds, it was found that the supramolecular structures are governed by similar predominant patterns, viz. strong intermolecular N-H...N(pyrazine) hydrogen bonds supplemented by weak C-H∙∙∙N(pyrazine) hydrogen-bond interactions in the 2- and 3-halo compounds and by C-H∙∙∙Cl/Br interactions in the 4-halo compounds. In all compounds, there are π-π stacking interactions.

Determination by ICP-MS of Essential and Toxic Trace Elements in Gums and Carrageenans Used as Food Additives Commercially Available in the Portuguese Market.

Gums and carrageenans are food additives widely used in food preparations to improve texture and as viscosifiers. Although they are typically added in small amounts, nowadays people tend to use more and more pre-prepared food. In this work, the content of a wide panel of trace elements in commercial products were analyzed. Carrageenans and gums (n = 13) were purchased in the Portuguese market and were from European suppliers. Samples were solubilized by closed-vessel microwave-assisted acid digestion and analyzed by ICP-MS. Globally, the content of essential trace elements decreased in the following order: Fe (on average, on the order of several tens of µg/g) > Mn > Zn > Cr > Cu > Co > Se > Mo (typically < 0.1 µg/g), while the content of non-essential/toxic trace elements decreased in the following order: Al > Sr > Rb > As > Li > Cd > Pb > Hg. The consumption of these food additives can significantly contribute to the daily requirements of some essential trace elements, namely Cr and Mo. The toxic trace elements Cd, As, Pb, and Hg were below the EU regulatory limits in all analyzed samples. Additional research is needed to define the potential risk of introducing toxic trace elements into food products through the use of these additives.

1,3-Bis(propan-2-yl)naphthalene.

In the title compound, C(16)H(20), one of the isopropyl groups shows almost equal displacements [1.252 (1) and -1.270 (1) Å] of its methyl-C atoms from the mean plane of the naphthalene ring system, while the other shows asymmetric displacements [1.586 (2) and -0.315 (1) Å]. In the crystal, the mol-ecules are linked into sheets lying in the ab plane by three C-H⋯π contacts, two involving donors belonging to the isopropyl groups and the third a donor atom from the naphthalene ring system. The different orientations of the isopropyl groups might be attributed to the fact that the C-H⋯π inter-action involving one of them is enhanced by the C-H⋯π inter-action involving the aromatic ring.

Recent Approaches on Signal Transduction and Transmission in Acupuncture: A Biophysical Overview for Medical Sciences.

Acupuncture is one of the areas among the alternative therapies that arise high curiosity in the biomedical scientific community. It is particularly popular for treatment of chronic diseases and addictions. However, contrasting with its evidence-based effectiveness, the lack of reasonable explanations for its mode of action divides that scientific community. Difficulties also arise to those responsible for providing information for clinicians and professionals who wish to acquire competencies leading to the acupuncture practice and have a background based on biochemistry and physiology. The classic theories of nerve conduction do not fully explain how information is read and transmitted during the acupuncture treatment. Other theories have been proposed, but they are based on concepts such as biophotonic waves and quantum biochemistry that are difficult to read and understand by those who do not have knowledge in physics. It is the main objective of this review to provide a summary of the main theories and explanatory approaches to the signal transduction and conduction in acupuncture and to describe them in terms of their explanatory hypotheses, limitations, and weaknesses. The most of the literature found support theories for neural conduction, including gate control. They explain the effects of acupuncture in pain relief; few studies have been conducted concerning the conduction based on biophotons. The primo vascular system has been referred as a possible anatomic support for conduction of information during an acupuncture treatment, which could be connected to biophoton transmission.

Structural characterization of some N-phenyl-4-oxo-4H-2-chromone carboxamides.

N-phenyl-4-oxo-4H-2-chromone carboxamides were found to be inactive as MAO inhibitors in contrast with their N-phenyl-4-oxo-4H-3-chromone carboxamide isomers. In order to obtain a close insight into the docking mechanism for this family of compounds, the molecular and supramolecular structures of nine N-phenyl-4-oxo-4H-2-chromone carboxamides were determined. It was found that, in most of the secondary structures, the N(amido) and the O(carboxyl) of the carboxamide residue participate in strong intramolecular interactions, with the O atom of the chromene ring and with the H(ortho)-C (phenyl), respectively. When the phenyl ring had accessible acceptors as substituents a third intramolecular hydrogen bond was also observed. As a consequence, rotations of the chromone and phenyl rings around the N-C(alpha) and C(alpha')-C=O are constrained and the compounds were found to be more planar than would otherwise be expected. The deviation from planarity of the whole molecule can be quantified by the dihedral angles between mean planes of the aromatic rings and it was found that they were mainly affected by the degree of torsion of the phenyl ring with respect to the amide residue. The molecular conformations assumed by the secondary amides clearly contrast with that of a related tertiary amide that was also determined in this study. The unavailability of the N in this compound as a donor strongly influences the molecular isomerism and conformation. This analysis demonstrates that the molecules can be classified into four groups depending on the types of interactions formed as described above. If the secondary N(amido) of the carboximide is involved in two intramolecular interactions then this atom does not form any intermolecular contacts. In all other cases it does and the supramolecular structure formed is in most cases supplemented by weak C-H···O interactions.

Ethnopharmacological notes about ancient uses of medicinal plants in Trás-os-Montes (northern of Portugal).

AIM OF THE STUDY: In order to preserve the ancestral knowledge, an ethnopharmacological study has been carried out in two councils belonging to Trás-os-Montes region a small area located in the northern of Portugal. In that area, medicinal plants, most of the species wild, are still in use among farmers, shepherds and other people who live far from villages and built-up areas. MATERIALS AND METHODS: Among the 46 people that were interviewed (mean age of 66 years old), 88 species belonging to 42 families of vascular plants were identified for treatment of various human ailments. An ethnopharmacological report is made consisting of species names, vernacular names, popular uses of the plants and their pharmacological properties. RESULTS AND CONCLUSION: The most dominant family is Lamiaceae (18%) and the most frequently part of the plant used for the treatment of diseases are leaves (37.9%). The largest number of taxa is used to treat gastrointestinal disorders (73.9%).