N‐ and O‐linked glycosylation site profiling of the human basic salivary proline‐rich protein 3M

In the present study, we show that the heterogeneous mixture of glycoforms of the basic salivary proline‐rich protein 3M, encoded by PRB3‐M locus, is a major component of the acidic soluble fraction of human whole saliva in the first years of life. Reversed‐phase high‐performance liquid chromatography with high‐resolution electrospray ionization mass spectrometry analysis of the intact proteoforms before and after N‐deglycosylation with Peptide‐N‐Glycosidase F and tandem mass spectrometry sequencing of peptides obtained after Endoproteinase GluC digestion allowed the structural characterization of the peptide backbone and identification of N‐ and O‐glycosylation sites. The heterogeneous mixture of the proteoforms derives from the combination of 8 different neutral and sialylated glycans O‐linked to Threonine 50, and 33 different glycans N‐linked to Asparagine residues at positions 66, 87, 108, 129, 150, 171, 192, and 213.     

Isolation of Crithmum maritimum L. volatile oil by supercritical carbon dioxide extraction and biological assays

The chemical composition of the volatile concentrate obtained by supercritical CO2 extraction of aerial parts of Crithmum maritimum L. growing spontaneously in one area of Mediterranean coast (Buggerru, Sardinia Island, Italy) and in two areas of the Atlantic coast (Figueira da Foz and S. Pedro de Moel, Portugal) was investigated by GC and GC-MS. The major oil components identified were p-cymene, beta-phellandrene, gamma-terpinene, thymol methyl ether and dillapiole. The results showed the presence of two chemotypes of C. maritimum with different dillapiole contents, ranging from 0.2 to 64.2% in Portuguese and Italian plants, respectively. The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against yeasts and dermatophyte strains. All the oils exhibited significant antifungal activity against dermatophyte strains. The oil with the higher amount of dillapiole (64.2%) was the most active with MIC values ranging from 0.08-0.32 microL mL(-1).     

Comparative analysis of the oil and supercritical CO(2) extract of Schinus molle L. growing in Yemen

In this study, we report the preliminary data on the chemical composition of Yemeni Schinus molle L. volatile oil obtained by supercritical extraction with carbon dioxide (40°C and 90?bar), SFE, and by hydrodistillation (HD). The composition of the volatile oil has been analysed by GC and GC-MS. The content of the major constituents in the oils from leaves varied in the following ranges: germacrene D 3.7% in SFE and 16.7% in HD; β-caryophyllene 19.1% in SFE and 13.5% in HD. The amount of monoterpenes constituted 4%, in all the analysed samples, while the number of sesquiterpenes was 44% in supercritical and 67% in HD oil. Some compounds were not identified by GC-MS and it will require further analysis using other analytical techniques.     

Chemical composition and biological activity of the volatile extracts of Achillea millefolium

In this study, flowering aerial parts of wild Achillea millefolium growing on the Mediterranean coast (Sardinia Island, Italy) and on the Atlantic coast (Portugal- Serra de Montemuro) were used as a matrix for supercritical extraction of volatile oil with CO2 (SFE). The collected extracts were analyzed by GC-FID and GC-MS methods and their composition were compared with that of the essential oil isolated by hydrodistillation. A strong chemical variability in essential oils depending on the origin of the samples was observed. The results showed the presence of two type oils. The Italian volatile extracts (SFE and essential oil) are predominantly composed by alpha-asarone (25.6-33.3%, in the SFE extract and in the HD oil, respectively), beta-bisabolene (27.3-16.6%) and alpha-pinene (10.0-17.0%); whereas the main components of the Portuguese extracts are trans-thujone (31.4-29.0%), trans-crhysanthenyl acetate (19.8-15.8%) and beta-pinene (1.2-11.1%). The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, C. tropicalis, C. krusei, C. guillermondii, C. parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, T. mentagrophytes, T. mentagrophytes var. interdigitale, T. verrucosum, Microsporum canis, M. gypseum, Epidermophyton floccosum, Aspergillus niger, A. fumigatus and A. flavus. The oils showed the highest activity against dermatophyte strains, with MIC values ranging from 0.32-1.25 microL mL(-1).     

Chemoselective C-4 aerobic oxidation of catechin derivatives catalyzed by the Trametes villosa laccase/1-hydroxybenzotriazole system: synthetic and mechanistic aspects

Catechin derivatives were oxidized in air in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system in buffered water/1,4-dioxane as reaction medium. The oxidation products, flavan-3,4-diols and the corresponding C-4 ketones, are bioactive compounds and useful intermediates for the hemisynthesis of proanthocyanidins, plant polyphenols which provide beneficial health properties for humans. Determinations of oxidation potentials excluded that catechin derivatives could be directly oxidized by laccase Cu(II), while it resulted in the H-abstraction from benzylic positions being promptly promoted by the enzyme in the presence of the mediator HBT, the parent species producing in situ the reactive intermediate benzotriazole-N-oxyl (BTNO) radical. A remarkable and unexpected result for the laccase/HBT oxidative system has been the chemoselective insertion of the oxygen atom into the C-4-H bond of catechin derivatives. Mechanistic aspects of the oxidation reaction have been investigated in detail for the first time in order to corroborate these results. Since the collected experimental findings could not alone provide information useful to clarify the origin of the observed chemoselectivity, these data were expressly supplemented with information derived by suitable molecular modeling investigations. The integrated evaluation of the dissociation energies of the C-H bonds calculated both by semiempirical and DFT methods and the differential activation energies of the process estimated by a molecular modeling approach suggested that the observed selective oxidation at the C-4 carbon has a kinetic origin.     

Organocatalytic asymmetric tandem condensation-intramolecular rearrangement-protonation: an approach to optically active α-amino thioester derivatives

An unprecedented and conceptually novel chiral Br?nsted base/Br?nsted acid catalytic method for the enantioselective synthesis of α-amino thioesters through a tandem condensation-intramolecular rearrangement-protonation has been developed which provides a number of important synthetic building blocks in good yield and with moderate to good enantioselectivities.     

Reaction of 5-(1-bromo-2-aryl-vinyl)-3-methyl-4-nitro-isoxazoles and 1,3-dicarbonyl compounds

The preparation of E-5-(1-bromo-2-aryl-vinyl)-3-methyl-4-nitro-isoxazoles and their reaction with 1,3-dicarbonyl compounds to give cyclopropanes or dihydrofurans is described.     

Double diffusion for the programmable spatiotemporal patterning of multi-domain supramolecular gels

To achieve spatial resolution of a multi-component gel, a double diffusion approach is used which enables the precise programming of self-assembled patterned domains with well-defined shapes and sizes. The low-molecular-weight gelators (LMWGs) used in this study are pH-responsive DBS-CO₂H and thermally-responsive DBS-CONHNH₂ (both based on 1,3:2,4-dibenzylidenesorbitol, DBS). A DBS-CONHNH₂ gel was initially assembled in a tray, and then loaded at carefully-selected positions with either basified DBS-CO₂H (i.e. DBS-carboxylate) or an acid. These soluble components subsequently diffuse through the pre-formed gel matrix, and in the domains when/where they mix, protonation of the DBS-carboxylate induces self-assembly of the DBS-CO₂H network, leading to a patterned gel-in-gel object with well-defined shape and dimensions. Using a strong acid achieves fast gelation kinetics, creating smaller, better-defined macroscale objects but with less nanoscale order. Using a weak acid source with slow kinetics, gives slightly larger objects, but on the nanoscale the DBS-CO₂H network formation is better controlled, giving more homogeneous nanoscale structures and stiffer objects. The patterned objects can be further reinforced by the presence of agarose polymer gelator. The shape of the patterning is programmed by both the shape of the central reservoir and the starting geometry in which the reservoirs are organised, with the balance between factors depending on assembly kinetics, as dictated by the choice of acid. This simple methodology therefore enables programming of patterned gels with spatiotemporal control and emergent patterning characteristics.

To achieve spatial resolution of a multi-component gel, a double diffusion approach is used which enables the precise programming of emergent self-assembled patterned domains with well-defined shapes and sizes.     

Biological Effects on μ-Receptors Affinity and Selectivity of Arylpropenyl Chain Structural Modification on Diazatricyclodecane Derivatives

Opioid analgesics are clinically used to relieve severe pain in acute postoperative and cancer pain, and also in the long term in chronic pain. The analgesic action is mediated by μ-, δ-, and κ-receptors, but currently, with few exceptions for k-agonists, μ-agonists are the only ones used in therapy. Previously synthesized compounds with diazotricyclodecane cores (DTDs) have shown their effectiveness in binding opioid receptors. Fourteen novel diazatricyclodecanes belonging to the 9-propionyl-10-substituted-9,10-diazatricyclo[4.2.1.1^2,5]decane (compounds 20–23, 53, 57 and 59) and 2-propionyl-7-substituted-2,7-diazatricyclo[4.4.0.0^3,8]decane (compounds 24–27, 54, 58 and 60) series, respectively, have been synthesized and their ability to bind to the opioid μ-, δ- and κ-receptors was evaluated. Five of these derivatives, compounds 20, 21, 24, 26 and 53, showed μ-affinity in the nanomolar range with a negligible affinity towards δ- and κ-receptors and high μ-receptor selectivity. The synthesized compounds showed μ-receptor selectivity higher than those of previously reported methylarylcinnamyl analogs.