1,721,294 research outputs found
The 23(rd) National Meeting of the Medicinal Chemistry Division of the Italian Chemical Society (DCF-SCI) in Salerno (NMMC 2015)
No full textTop-notch Italian medicinal chemistry: Guest editors Pietro Campiglia and Gianluca Sbardella look back at the 2015 National Meeting of the Medicinal Chemistry Division of the Italian Chemical Society. They recall the history of the society and this annual conference and provide highlights of last year's events, as well as key papers and posters presented, which are now collected in this Special Issue
Unraveling the Active Conformation of Urotensin II
No full textUrotensin II (U-II) is a disulfide-bridged undecapeptide recently identified as the ligand of an orphan G-protein-coupled receptor. Human U-II (H-Glu-Thr-Pro-Asp-cyclo[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH) has been described as the most potent vasoconstrictor compound identified to date. With the aim of elucidating the active conformation of hU-II, we have performed a spectroscopic analysis of hU-II minimal active fragment hU-II(4-11) in different environmental conditions. The analysis indicated that hU-II(4-11) was highly structured in the anisotropic membrane mimetic SDS solution, showing a type II′ β-turn structure, which is almost unprecedented for L-amino acid peptides. Micelle bound structure of hU-II(4-11) was then compared with those of four synthetic analogues recently synthesized in our lab, bearing modified Cys residues at position 5 and/or position 10 and characterized by different levels of agonist activity. The structures of the active compounds were found to be very similar to that of hU-II(4-11), while a barely active compound does not show any propensity to β-turn formation. Furthermore, distances among putative pharmacophoric points in the structures of the active compounds obtained in SDS solution are in good agreement with those found in a recently described non-peptide agonist of the hU-II receptor. A type II′ β-turn structure was already found for the somatostatin analogue octreotide. On the basis of the similarity of the primary and 3D structures of U-II and somatostatin analogues and on the basis of the sequence homology between the GPR14/UT-II receptor and members of the somatostatin receptor family, a common evolutionary pathway for the signal transmission system activated by these peptide can be hypothesized
Aloe gel-base food products: Chemical, toxicological, and regulatory aspects
No full textAloe products are increasingly valued as ingredients in food supplements and flavoring agents. In early March 2020, the European Commission drafted a ban on the use of Aloe products that contain hydroxyanthracene derivatives (HADs) in food, following the opinion on concerns about the toxicity of vegetable extracts containing HADs carried out by the European Food Safety Authority (EFSA). Aloe gel preparation is characterized by minimal amounts of HADs, only present as contaminants during extraction, compared to other sold Aloe preparations such as Aloe latex and Aloe whole leaf extract. This review provides a comprehensive account of the toxicological aspects of Aloe gel, and briefly discusses the chemical profile of other Aloe preparations. Unlike these other preparations, pure Aloe gel shows no toxic effects. However, further toxicological studies remain necessary to establish the maximum permissible limit of HAD contaminants in Aloe gel, considering daily doses and maximum duration of treatments. Finally, officially validated analytical methods for determination of HADs are required, in the form of tools for use by Companies and Competent Authorities to ensure the absence of HAD contamination in raw materials or in finished products
Highly efficient synthesis and chemical separation of 5-amino- and 7-amino-4-hydroxy-2-naphthoic acids
No full textNutraceutical potential of monofloral honeys produced by the Sicilian black honeybees (Apis mellifera ssp. sicula)
No full textIn the light of the growing interest in food and food products obtained through organic and environmentally friendly techniques, the present work represents the first approach to the evaluation of the biological profile of some Sicilian honeys produced in purity by the local black honeybees. Samples exhibited up to 10 times more total phenolics and higher antioxidant capacity than what already reported for the same variety of honeys produced by other honeybee subspecies from Sicily, other Italian regions and abroad. Noteworthy, the gallic acid contents in medlar and almond honeys represented the highest level of single phenolic acid reported in honey so far. A broad antimicrobial spectrum was showed by all of the honey samples and a good correlation between their inhibition capacity and polyphenolic contents was measured. Experimental results highlighted samples among the honeys characterised by the highest nutraceutical added value and most excellent quality
Cycloaddition reactions of thiazolidine derivatives. An approach to the synthesis of new functionalized heterocyclic systems
No full textA one-pot procedure for the synthesis of two functionalized tricyclic systems having structures of benzo[g]isoquinoline-5,10-dione and dihydrothieno[2,3-b]naphto-4,9-dione (DTNQ) is described. These new series were synthesized from cycloaddition reactions between naphthoquinone and arylthiazolidine derivatives, the latter acting, respectively, as highly reactive N-aryl-idenedehydroalanine ethyl esters (2-AD) or as amino ester nucleophilic species. (C) 2001 Elsevier Science Ltd. All rights reserved
Unraveling the active conformation of urotensin II
No full textUrotensin II (U-II) is a disulfide-bridged undecapeptide recently identified as the ligand of an orphan G-protein-coupled receptor. Human U-II (H-Glu-Thr-Pro-Asp-cyclo[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH) has been described as the most potent vasoconstrictor compound identified to date. With the aim of elucidating the active conformation of hU-II, we have performed a spectroscopic analysis of hU-II minimal active fragment hU-II(4-11) in different environmental conditions. The analysis indicated that hU-II(4-11) was highly structured in the anisotropic membrane mimetic SDS solution, showing a type II' beta-turn structure, which is almost unprecedented for L-amino acid peptides. Micelle bound structure of hU-II(4-11) was then compared with those of four synthetic analogues recently synthesized in our lab, bearing modified Cys residues at position 5 and/or position 10 and characterized by different levels of agonist activity. The structures of the active compounds were found to be very similar to that of hU-II(4-11), while a barely active compound does not show any propensity to beta-turn formation. Furthermore, distances among putative pharmacophoric points in the structures of the active compounds obtained in SDS solution are in good agreement with those found in a recently described non-peptide agonist of the hU-II receptor. A type II' beta-turn structure was already found for the somatostatin analogue octreotide. On the basis of the similarity of the primary and 3D structures of U-II and somatostatin analogues and on the basis of the sequence homology between the GPR14/UT-II receptor and members of the somatostatin receptor family, a common evolutionary pathway for the signal transmission system activated by these peptide can be hypothesized
Ultrasonic assisted production of nanoliposomes as peptide delivery vectors
No full textIn this work, preparation and characterization of liposomal Small Unilamellar Vesicles (SUVs), loaded with a cationic peptide, purposely designed for cardiovascular diseases treatment, are presented. In particular, the attention has been focused on vesicles size and peptide load achievable by a protocol based on duty cycle sonication to form loaded SUVs starting from large vesicles. The applied technique gives the possibility to obtain liposomal vesicles-protecting peptides of tunable size according to the route of administration chosen for the delivery of peptid
- …
