Publications by authors named "Federico Pepi"

Chronic intestinal inflammation and neo-angiogenesis are interconnected in colorectal carcinoma (CRC) pathogenesis. Molecules reducing inflammation and angiogenesis hold promise for CRC prevention and treatment. N-Palmitoyl-d-glucosamine (PGA), a natural glycolipid analog with anti-inflammatory properties, has shown efficacy against acute colitis.

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Carbon dots (CDs) obtained from 5-(hydroxymethyl)furfural (5-HMF) were activated by a 365 nm-UV irradiation source and employed in the Knoevenagel condensation to investigate their photocatalytic mechanism. To this end, electrospray ionization mass spectrometry (ESI-MS) was used to monitor the time progress of the condensation and follow the formation of the final product in positive and negative ion modes at once. The intervention of the superoxide radical anion in the photocatalytic mechanism of CDs was highlighted.

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Improving clinical outcomes and delaying disease recrudescence in Ulcerative Colitis (UC) patients is crucial for clinicians. In addition to traditional and new pharmacological therapies that utilize biological drugs, the development of medical devices that can ameliorate UC and facilitate the remission phase should not be overlooked. Drug-based therapy requires time to be personalized and to evaluate the benefit/risk ratio.

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Article Synopsis
  • Researchers successfully achieved the asymmetric synthesis of warfarin using microdroplets and thin films created by an electrospray ionization (ESI) technique.
  • This study represents one of the first instances of an enantioselective organocatalyzed reaction taking place in confined spaces generated by electrospraying.
  • The team identified the best conditions necessary for performing this chemical reaction efficiently within the ESI system.
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  • - The study explores the esterification of amino acids with methanol using HSO as a catalyst, specifically in tiny thin films created by ESI microdroplet deposition.
  • - The reaction is most efficient at a thin film temperature of 70 °C, with essential factors like microdroplet size and film lifetime affecting the outcome.
  • - l-tyrosine and l-phenylalanine, with their aromatic side chains, exhibit the highest reactivity, achieving yields of about 40-50%, showing that this thin film method produces results not seen in bulk reactions.
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  • A study investigates the oxidative pathways of sulfur dioxide using different zinc compounds (ZnO, Zn(NO₃)₂, and Zn(NO₃)(NO₂)), employing mass spectrometry and theoretical calculations.
  • The reactions are driven by specific zinc-oxygen interactions or low-valence zinc, which transfers oxygen ions or electrons to sulfur dioxide.
  • Findings indicate that the presence of NO ligands becomes significant when sulfur dioxide is transformed into sulfur oxides (SO₂ and SO₃), resulting in the formation of zinc sulfate and sulfite, with the reactions happening quickly and through similar energy processes.
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  • The study focused on analyzing the oil extracted from pomegranate seeds of the "Granata" cultivar to uncover their chemical composition and potential value, often overlooked in conventional practices.
  • Using Soxhlet extraction with hexane and supercritical CO2 extraction with ethanol, researchers evaluated the oils using advanced techniques like NMR and AP-MALDI-MS, discovering that punicic acid was the dominant component in the oils, especially in the supercritical extract.
  • Additionally, solid phase extraction and HPLC-DAD analyses were used to isolate polyphenolics, revealing that the supercritical CO2 extract had a higher antioxidant activity compared to the Soxhlet extract.
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The peroxymonocarbonate anion, HCO, the covalent adduct between the carbon dioxide and hydrogen peroxide anion, effectively reacts with SO in the gas phase following three oxidative routes. Mass spectrometric and electronic structure calculations show that sulphur dioxide is oxidised through a common intermediate to the hydrogen sulphate anion, sulphur trioxide, and sulphur trioxide anion as primary products through formal HO, oxygen atom, and oxygen ion transfers. The hydrogen sulphite anion is also formed as a secondary product from the oxygen atom transfer path.

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The Maillard reaction kinetics in the confined volume of the thin film produced by ESI microdroplet deposition was studied by mass spectrometry. The almost exclusive formation of the Amadori product from the reaction of D-xylose and D-glucose toward L-glycine and L-lysine was demonstrated. The thin film Maillard reaction occurred at a mild synthetic condition under which the same process in solution was not observed.

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Rationale: The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry.

Methods: Three different Brønsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAI - H).

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Thin films derived by the deposition of charged microdroplets generated in the ESI source of a mass spectrometer act as highly concentrated reaction vessels in which the final products of an ion-molecule reaction can be isolated by their precipitation onto a solid surface under ambient conditions. In this study, the ESI Z-spray source supplied to a Q-TOF Ultima mass spectrometer was used to investigate the d-fructose acid-catalyzed reactions by microdroplets deposition onto a stainless-steel target surface. High conversion ratios of d-fructose into 5-hydroxymethylfuraldehyde (5-HMF), 5-methoxymethylfuraldehyde (5-MMF), and difructrose anhydrides (DFAs) were obtained with HCl and KHSO as metal-free catalysts by using synthetic conditions under which the same products in bulk are not formed.

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The reactivity of [NaL·ClO] cluster anions (L = ClO; x = 0-3) with sulphur dioxide has been investigated in the gas phase by ion-molecule reaction experiments (IMR) performed in an in-house modified Ion Trap mass spectrometer (IT-MS). The kinetic analysis revealed that SO is efficiently oxidised by oxygen-atom (OAT), oxygen-ion (OIT) and double oxygen transfer (DOT) reactions. The main difference from the previously investigated free reactive ClO is the occurrence of intracluster OIT and DOT processes, which are mediated by the different ligands of the chlorite anion.

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N-heterocyclic carbenes (NHCs) are key intermediates in a variety of chemical reactions. Owing to their transient nature, the interception and characterization of these reactive species have always been challenging. Similarly, the study of reaction mechanisms in which carbenes act as catalysts is still an active research field.

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Article Synopsis
  • A gas-phase study explored how d-fructose dehydrates in the presence of various bases using mass spectrometry and theoretical calculations.
  • Electrospray ionization produced protonated d-fructose addition products, allowing the investigation of intermediates and reaction pathways.
  • The study concluded that the final product, protonated 5-hydroxymethyl-2-furaldehyde (5-HMF), forms more effectively with specific bases that remain clustered throughout the dehydration process.
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A comprehensive study on essential oil samples extracted from Moris (Apiaceae) collected in Tarquinia (Italy) is reported. In this study, a 30-hour, fractionated, steam distillation procedure for essential oil preparation was applied. The gas chromatographic-mass spectrometry analysis showed monoterpene -cymene and phenylpropanoid dill-apiol as the major essential oil's constituents revealing a new chemotype dependent on extraction duration.

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Heparanase is the only mammalian endo-β-d-glucuronidase involved in a variety of major diseases. The up-regulation of heparanase expression increases tumor size, angiogenesis, and metastasis, representing a validated target in the anti-cancer field. To date, only a few small-molecule inhibitors have been described, but none have gotten through pre-clinical development.

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Furan derivatives, potentially carcinogenic to humans, can be formed, in addition to carbohydrates and other sources, from the degradation of ascorbic acid (AA). At present, the mechanisms involved in the ascorbic acid degradation are not yet fully understood. In this study, we reported a gas-phase investigation, performed using Triple Quadrupole (TQ/MS) and Ion Trap Mass Spectrometry (QIT/MS) together with quantum mechanical calculations at the B3LYP/6-31+G(d,p) level of theory, on the non-oxidative degradation mechanism of l-ascorbic acid (AA) to furan derivatives.

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is a ubiquitous organism and opportunistic pathogen that can cause persistent infections due to its peculiar antibiotic resistance mechanisms and to its ability to adhere and form biofilm. The interest in the development of new approaches for the prevention and treatment of biofilm formation has recently increased. The aim of this study was to seek new non-biocidal agents able to inhibit biofilm formation, in order to counteract virulence rather than bacterial growth and avoid the selection of escape mutants.

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A comprehensive study on essential oil samples of Foeniculum vulgare Miller from Tarquinia (Italy) is reported. A 24-h systematic steam distillation was performed on different harvested samples applying different extraction times. The GC-MS analysis of the residue outcome showed o-cymene, α-phellandrene, α-pinene and estragole as the major constituents.

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Steam distillation is known to be the most prevalent method of essential oil extraction. Despite many studies on extraction methods, there is no report about the impact of distillation process duration on the yield and oil quality. A new 24-h steam distillation process for extraction of plant essential oils is presented.

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Traditional cleaning methods with organic solvents often are not suitable for removal of aged resin so researchers have to find new formulations. In this work, a case study is reported in which new microemulsions were applied on the surface of a painting covered by some aged resin layers used during a previous restoration. Based on the quality of the intervention and the analysis of a sample of the varnish carried out with both MALDI-TOF and ATR-IR spectrometers, it was conjectured that this undesired material could be an acrylic polymer.

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In order to investigate the gas-phase mechanisms of the acid catalyzed degradation of ascorbic acid (AA) to furan, we undertook a mass spectrometric (ESI/TQ/MS) and theoretical investigation at the B3LYP/6-31 + G(d,p) level of theory. The gaseous reactant species, the protonated AA, [C H O ]H , were generated by electrospray ionization of a 10  M H O/CH OH (1 : 1) AA solution. In order to structurally characterize the gaseous [C H O ]H ionic reactants, we estimated the proton affinity and the gas-phase basicity of AA by the extended Cooks's kinetic method and by computational methods at the B3LYP/6-31 + G(d,p) level of theory.

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A series of N,N-dimethylcarbamates containing a N,N-dibenzylamino moiety was synthesized and tested to evaluate their ability to inhibit Acetylcholinesterase (AChE). The most active compounds 4 and 8, showed 85 and 69% of inhibition at 50 μM, respectively. Furthermore, some basic SAR rules were outlined: an alkyl linker of six methylene units is the best spacer between the carbamoyl and dibenzylamino moieties; electron-withdrawal substituents on aromatics rings of the dibenzylamino group reduce the inhibitory power.

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