Langmuir-Blodgett films incorporating redox mediators for molecular recognition of NADH

We focused our studies on the fabrication of nano-organized systems incorporating redox mediators for NADH. We fabricated gold-modified electrodes of phospholipid layers containing a redox mediator for NADH by means of the Langmuir-Blodgett (LB) technique. We chose tetramethylbenzidine (TMB) which is known to decrease the very large overvoltage involved in the direct oxidation of NADH. The electrochemical characterisation of the films allowed to determine the presence and the electrochemical activity of the mediator in the LB layers. The response of the sensing layer in solutions containing NADH was investigated by means of cyclic voltammetry and fluorescence spectroscopy. We observed that NADH has a strong affinity with the film, and it interacts with the TMB-containing phospholipid layers. In fact, we found that TMB molecules mediate the NADH oxidation reaction, even if the surrounding matrix relatively hinders their mobility.     

2,2-dimethyl cyclopentanones by acid catalyzed ring expansion of isopropenylcyclobutanols. A short synthesis of (+/-)-alpha-cuparenone and (+/-)-herbertene

2,2-dimethyl cyclopentanones are readily prepared by acid catalyzed ring expansion of isopropenylcyclobutanols; the method allows ready access to the family of sesquiterpenes cuparanes and herbertanes, as demonstrated by the synthesis of (+/-)-alpha-cuparenone and the direct precursor of (+/-)-herbertene.     

Chemical composition of the essential oils of the berries of Juniperus oxycedrus L. ssp. rufescens (L. K.) and Juniperus oxycedrus L. ssp. macrocarpa (S. & m.) Ball. and their antioxidant activities

This study is outlined to probe the chemical composition of essential oil and in vitro antioxidant activity of Juniperus oxycedrus ssp. macrocarpa (S. & m.) Ball. and Juniperus oxycedrus L. ssp. rufescens (L. K.) berries, collected from four sites, according to their maturity phase. The chemical composition of the hydrodistilled essential oil was analysed by GC-MS. Forty-eight compounds were identified, accounting for approximately 79.8-98.9% of the oil. The main constituents were α-pinene, germacrene D, myrcene, abietadiene and cis-calamenene, their mean percentage vary according to their phenological stage. The antioxidant activity of the samples was determined by the ABTS and DPPH radical scavenging activities. Hawaria essential oil extracted from mature berries showed the highest antioxidant capacity.     

Sequential Assembly of Mutually Interactive Supramolecular Hydrogels and Fabrication of Multi-Domain Materials

A two-component self-sorting hydrogel based on acylhydrazide and carboxylic acid derivatives of 1,3:2,4-dibenzylidene-d -sorbitol (DBS-CONHNH₂ and DBS-COOH) is reported. A heating–cooling cycle induces the self-assembly of DBS-CONHNH₂, followed by the self-assembly of DBS-COOH induced by decreasing pH. Although the networks are formed sequentially, there is spectroscopic evidence of interactions between them, which impact on the mechanical properties and significantly enhance the ability of these low-molecular-weight gelators (LMWGs) to form gels when mixed. The DBS-COOH network can be switched “off” and “on” within the two-component gel through a pH change. By using a photo-acid generator, the two-component gel can be prepared combining the thermal trigger with photo-irradiation. Photo-patterned self-assembly of DBS-COOH within a pre-formed DBS-CONHNH₂ gel under a mask yields spatially controlled multi-domain gels. Different gel domains can have different functions, for example, controlling the rate of release of heparin incorporated into the gel, or directing gold nanoparticle assembly. Such photo-patterned multi-component hydrogels have potential applications in regenerative medicine or bio-nano-electronics.     

Chemical composition and biological assays of essential oils of Calamintha nepeta (L.) Savi subsp. nepeta (Lamiaceae)

Aerial parts of wild Calamintha nepeta (L.) Savi subsp. nepeta growing spontaneously on the Mediterranean coast (Sardinia Island, Italy) and on the Atlantic coast (Portugal) were used as a matrix for the supercritical extraction of volatile oil with CO(2). The collected extracts were analysed by GC-FID and GC-MS methods and their compositions were compared with that of the essential oil isolated by hydrodistillation, but the differences were not relevant. A strong chemical variability was observed in the essential oils depending on the origin of the samples. The results showed the presence of two chemotypes of C. nepeta. In all Italian samples, pulegone, piperitenone oxide and piperitenone were the main components (64.4-39.9%; 2.5-19.1%; 6.4-7.7%); conversely, the oil extracted from Portuguese C. nepeta is predominantly composed of isomenthone (35.8-51.3%), 1,8-cineole (21.1-21.4%) and trans-isopulegone (7.8-6.0%). The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The Italian oil, rich in pulegone, exhibited significant antifungal activity against Aspergillus and dermatophyte strains, with MIC values of 0.32-1.25 μL mL(-1).     

Anti-inflammatory activity of Pistacia lentiscus essential oil: involvement of IL-6 and TNF-alpha

The topical anti-inflammatory activity of essential oil of Pistacia lentiscus L. was studied using carrageenan induced rat paw edema and cotton pellet induced granuloma. The effect on serum tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in rats inserted with cotton pellet was also investigated. On topical application, the oil exhibited a significant decrease in paw edema. The oil also inhibited cotton pellet-induced granuloma, and reduced serum TNF-alpha and IL-6. It can be concluded that the essential oil of Pistacia lentiscus reduces leukocyte migration to the damaged tissue and exhibits anti-inflammatory activity.     

Chemical polymorphism of essential oils from populations of Laurus nobilis grown on Tunisia, Algeria and France

The compositions of the essential oils isolated from the aerial parts of tree Mediterranean populations of Laurus nobilis L. collected during the flowering phase on Tunisia, Algeria and France, were studied by GC and GC-MS. The analysis has allowed identifying 54 components. The main components were 1,8-cineole, alpha-terpinyl acetate (10-18.6%), methyl eugenol (10-22.1%), sabinene (1.2-8%), eugenol (1.2-11.7%) alpha-pinene (tr-4.5%) and beta-pinene (0.4-4.2%). The monoterpene fraction was dominant in all the oils analysed and consisted mainly of oxygenated monoterpenes. The oils from the tree populations studied showed a clear chemical polymorphism. The principal component and the hierarchical cluster analyses separated the Laurus nobilis leaf essential oils into three groups.     

A facile synthesis of 3,5-diaminopyrazole-4-carbothioamides and 3,5-diaminopyrazole-4-carboxylates

Simple and convenient synthesis of hitherto unknown 3,5-diaminopyrazole-4-carbothioamides 3 as well as new ethyl 3,5-diaminopyrazole-4-carboxylates 7 is reported. The key intermediates were 2-cyano-propenethioamides 2 and 2-(ethoxycarbonyl)propenethioamides 5 which were readily obtained by reaction of phenyl isothiocyanate with 3-(2-acylhydrazino)-3-aminopropenenitriles 1 and ethyl 3-(2-acylhydrazino)-3-aminopropenoates 4 respectively. Intramolecular cyclization of compounds 2 afforded pyrazole-4-carbothioamides 3 while propenethioamides 5 gave pyrazole-4-carboxylates 7 .