Analisi di oli essenziali di <i>Citrus</i> durante il periodo di maturazione del frutto

Gli oli essenziali del genere Citrus costituiscono un’importante classe di prodotti il cui utilizzo è molteplice. Nel campo alimentare sono utilizzati come aromatizzanti, nella profumeria per la formulazione di profumi con particolari “note di testa”, in campo farmaceutico come aromatizzanti. Vista l’importanza di questi oli abbiamo ritenuto interessante valutare la variabilità del loro contenuto in rapporto al grado di maturazione del frutto. La nostra indagine ha riguardato gli oli essenziali di due cultivar pigmentate: Moro e tarocco ed una cultivar bionda locale: San vito

Idroformilazione selettiva del 1,3-diisopropenilbenzene per la sintesi del Florhydral®

Il Florhydral®, 3-(3'-isopropenilfenil)butanal, è una fragranza di sintesi commercializzata a partire dal m-diisopropenilbenzene I ed il passaggio chiave dello schema di sintesi è rappresentato dall'idroformilazione di questa di olefina catalizzata da complessi di rodio. L'oxosintesi, anche se altamente chemioselettiva, presenta però una selettività piuttosto bassa verso la desiderata monoaldeide II, precursore del Florhydral®, fornendo anche il prodotto dialdeidico III. Abbiamo pertanto effettuato uno studio più approfondito di idroformilazione in presenza di vari sistemi catalitici sia omogenei che eterogenei con lo scopo di ottenere selettivamente la monoaldeide, che viene convertita nel desiderato Florhydral® IV tramite idrogenazione catalitica del doppio legame alchilico utilizzando 10 atm di H2 e Pd/C al 5% come catalizzatore

Interactions of GFAP with ceftriaxone and phenytoin: SRCD and molecular docking and dynamic simulation

Abstract Background GFAP is the major intermediate filament protein in mature astrocytes. Its increased expression and aggregation was firstly associated to Alexander's disease, and successively in different neurological diseases including scrapie, Alzheimer's and Creutzfeld–Jacob diseases. Recently, ceftriaxone a multi-potent β-lactam antibiotic able to overcome the blood–brain barrier, successfully eliminated the cellular toxic effects of misfolded mutated GFAP, similarly to phenytoin sodium, in a cellular model of Alexander's disease and inhibited α-synuclein aggregation protecting PC12 cells from the exposure to 6-hydroxydopamine. Methods In this study, synchrotron radiation circular dichroism spectroscopy has been used to obtain structural information about the GFAP-ceftriaxone (phenytoin) interactions, while computational methods allowed the identification of the relevant putative binding site of either ceftriaxone or phenytoin on the dimer structure of GFAP, permitting to rationalize the spectroscopic experimental results. Results We found that GFAP exhibited enhanced stability upon the addition of two equivalents of each ligands with ceftriaxone imparting a more spontaneous interactions and a more ordered complex system than phenytoin. Conclusions SRCD data and MD models indicate a stronger protective effect of ceftriaxone in neurological disorders characterized by an increased production and polymerization of GFAP. General significance This result, in addition to our previous works in which we documented that ceftriaxone interacts with α-synuclein inhibiting its pathological aggregation and that a cyclical treatment with this molecule in a patient with adult-onset Alexander's disease halted, and partly reversed, the progression of neurodegeneration, suggests the possibility of a chaperone-like effect of ceftriaxone on protein involved in specific neurodegenerative diseases

Rosmarinus officinalis L.: chemical modifications of the essential oil and evaluation of antioxidant and antimicrobial activity.

Rosmarinus officinalis essential oil was separated into its hydrocarbon and oxygenated fractions. The major compounds in the hydrocarbon fraction were α-pinene (44.2%), camphene (24.5%), and limonene (11.7%), while in the oxygenated fraction they were 1,8-cineole (37.6%), camphor (16.5%), and bornyl acetate (21.4%). The hydrocarbon fraction was submitted to a hydroformylation process and the antioxidant activity of the product was screened by the DPPH and β-carotene/linoleic acid tests. The hydroformylated fraction maintained the antioxidant activity of the whole oil. The MIC (minimal inhibitory concentration) and the MBC (minimal bactericidal concentration) of the essential oil, hydrocarbon, oxygenated and hydroformylated fractions were also tested on several microorganisms. Aeromonas sobria and Candida strains were the most susceptible micro-organisms. The hydroformylated fraction exhibited a MBC against Candida strains resistant to the other fractions

Comparative enantioseparation of planar chiral ferrocenes on polysaccharide-based chiral stationary phases.

Planar chiral ferrocenes are well-known compounds that have attracted interest for application in synthesis, catalysis, material science, and medicinal chemistry for several decades. In spite of the fact that asymmetric synthesis procedures for obtaining enantiomerically enriched ferrocenes are available, sometimes, the accessible enantiomeric excess of the chiral products is unsatisfactory. In such cases and for resolution of racemic planar chiral ferrocenes, enantioselective high-performance liquid chromatography (HPLC) on polysaccharide-based chiral stationary phases (CSPs) has been used in quite a few literature articles. However, although moderate/high enantioselectivities have been obtained for planar chiral ferrocenes bearing polar substituents, the enantioseparation of derivatives containing halogens, or exclusively alkyl groups, remains rather challenging. In this study, the enantioseparation of ten planar chiral 1,2- and 1,3-disubstituted ferrocenes was explored by using five polysaccharide-based CSPs under multimodal elution conditions. Baseline enantioseparations were achieved for nine analytes with separation factors (α) ranging from 1.20 to 2.92. The presence of π-extended systems in the analyte structure was shown to impact affinity of the most retained enantiomer toward amylose-based selectors, observing retention times higher than 80 min with methanol-containing mobile phases (MPs). Electrostatic potential (V) analysis and molecular dynamics (MD) simulations were used in order to study interaction modes at the molecular level

Exploring interaction modes between polysaccharide-based selectors and biologically active 4,4′-bipyridines by experimental and computational analysis

In the last few years, chiral 4,4′-bipyridine derivatives have been developed for different applications in catalysis, enantioseparation science, supramolecular and theoretical chemistry by modulating the activity of the molecular system through the introduction of specific substituents in the heteroaromatic scaffold. More recently, the biological activity of 2′-substituted-3,3′,5,5′-tetrachloro-2-iodo-4,4′-bipyridines has been explored in the field of transthyretin (TTR) fibrillogenesis inhibition, and the anticancer cytotoxicity of some derivatives is currently under systematic investigation. In this frame, the high-performance liquid chromatography (HPLC) enantioseparation of four atropisomeric 2,2′-disubstituted-4,4′-bipyridines (R, R’ = Ar, I), which contain multiple interaction sites, such as hydrogen bonding (HB) donors and acceptors, halogen bond (XB) donors, and -extended electronic clouds, was explored by using n-hexane (Hex)/2-propanol (2-PrOH) 90:10 v/v as a mobile phase (MP), and eight chiral columns with coated and immobilized amylose- and cellulose-based relectors. The impact of subtle structural variations of analytes and selectors on their mutual intermolecular interactivity was evaluated in terms of retention (k) and selectivity () factors. On this basis, chromatographic analysis based on systematic screening of analytes and selectors was integrated with electrostatic potential (V) analysis and molecular dynamics (MD) simulations as computational techniques. The effect of temperature on retention, selectivity, and enantiomer elution order (EEO) of the analytes with coated and immobilized amylose tris(3,5-dimethylphenylcarbamate) was also considered by comparing the variation of the thermodynamic profile associated with each enantioseparation. Chromatographic responses proved to be strictly dependent on specific regions within the analyte, and functions of different interactions sites of the analytes as the structure of the chiral selector changes were significantly disclosed

Enantioseparation of 5,5'-Dibromo-2,2'-Dichloro-3-Selanyl-4,4'-Bipyridines on Polysaccharide-Based Chiral Stationary Phases: Exploring Chalcogen Bonds in Liquid-Phase Chromatography

he chalcogen bond (ChB) is a noncovalent interaction based on electrophilic features of regions of electron charge density depletion (σ-holes) located on bound atoms of group VI. The σ-holes of sulfur and heavy chalcogen atoms (Se, Te) (donors) can interact through their positive electrostatic potential (V) with nucleophilic partners such as lone pairs, π-clouds, and anions (acceptors). In the last few years, promising applications of ChBs in catalysis, crystal engineering, molecular biology, and supramolecular chemistry have been reported. Recently, we explored the high-performance liquid chromatography (HPLC) enantioseparation of fluorinated 3-arylthio-4,4-bipyridines containing sulfur atoms as ChB donors. Following this study, herein we describe the comparative enantiosepa-ration of three 5,5-dibromo-2,2-dichloro-3-selanyl-4,4-bipyridines on polysaccharide-based chiral stationary phases (CSPs) aiming to understand function and potentialities of selenium σ-holes in the enantiodiscrimination process. The impact of the chalcogen substituent on enantioseparation was explored by using sulfur and non-chalcogen derivatives as reference substances for comparison. Our investigation also focused on the function of the perfluorinated aromatic ring as a π-hole donor recognition site. Thermodynamic quantities associated with the enantioseparation were derived from van't Hoff plots and local electron charge density of specific molecular regions of the interacting partners were inspected in terms of calculated V. On this basis, by correlating theoretical data and experimental results, the participation of ChBs and π-hole bonds in the enantiodiscrimination process was reasonably confirmed

Modificazioni semisintetiche dell'olio essenziale di <i>Myrtus communis</i> L. vegetante spontaneo in Sardegna e valutazione dell'attività antimicrobica

Il Myrtus communis, in Sardegna, e non solo, ha sempre rivestito un ruolo importante sia nel campo liquoristico alimentare che anche per le sue proprietà medicamentose. In questo lavoro è stato studiato l’olio essenziale di questa pianta, prendendolo come prodotto di partenza per effettuare delle modificazioni chimiche sulla componente terpenica portando alla formazione di specifici gruppi funzionali

Sintesi ed attività biologica di diossolo[4,5-f]indoli-3-beta-diketoacidi e studi di docking nel sito attivo dell'enzima HIV-1 integrasi

In precedenti comunicazioni stata riportata la sintesi di indoli 2-(3-)-β-diketoacidi 1a-f e 2a,c,e. In questo studio è riportata la sintesi, l'attività  biologica e gli studi di modellistica molecolare condotti sui derivati 2b,d a completamento delle precedenti ricerche

Graz Endocrine Causes of Hypertension (GECOH) study: a diagnostic accuracy study of aldosterone to active renin ratio in screening for primary aldosteronism

<p>Abstract</p> <p>Background</p> <p>Primary aldosteronism (PA) affects approximately 5 to 10% of all patients with arterial hypertension and is associated with an excess rate of cardiovascular complications that can be significantly reduced by a targeted treatment. There exists a general consensus that the aldosterone to renin ratio should be used as a screening tool but valid data about the accuracy of the aldosterone to renin ratio in screening for PA are sparse. In the Graz endocrine causes of hypertension (GECOH) study we aim to prospectively evaluate diagnostic procedures for PA.</p> <p>Methods and design</p> <p>In this single center, diagnostic accuracy study we will enrol 400 patients that are routinely referred to our tertiary care center for screening for endocrine hypertension. We will determine the aldosterone to active renin ratio (AARR) as a screening test. In addition, all study participants will have a second determination of the AARR and will undergo a saline infusion test (SIT) as a confirmatory test. PA will be diagnosed in patients with at least one AARR of ≥ 5.7 ng/dL/ng/L (including an aldosterone concentration of ≥ 9 ng/dL) who have an aldosterone level of ≥ 10 ng/dL after the saline infusion test. As a primary outcome we will calculate the receiver operating characteristic curve of the AARR in diagnosing PA. Secondary outcomes include the test characteristics of the saline infusion test involving a comparison with 24 hours urine aldosterone levels and the accuracy of the aldosterone to renin activity ratio in diagnosing PA. In addition we will evaluate whether the use of beta-blockers significantly alters the accuracy of the AARR and we will validate our laboratory methods for aldosterone and renin.</p> <p>Conclusion</p> <p>Screening for PA with subsequent targeted treatment is of great potential benefit for hypertensive patients. In the GECOH study we will evaluate a standardised procedure for screening and diagnosing of this disease.</p