Dipartimento di Chimica e Tecnologie Chimiche - Tesi di Dottorato

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Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Chimica e Tecnologie Chimiche dell'Università della Calabria.

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Author: search.filters.author.Sindona, GiovanniHas files: Yes

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    Eco-friendly extraction of bioactive compounds from olive (drupes and leaves), Stevia and Schizochytrium sp.
    (2017-04-13) Santoro, Ilaria; Andò, Sebastiano; Sindona, Giovanni; Nardi, Monica
    The use of nutraceutical compounds, as well as their extraction from natural sources, is now the subject of studies in various sectors. The research groups working in this field focus their attention on the optimization of extraction methods that combine the economic aspect with the ecological one. High-value active principles can be recovered from wastes of agri-food farms or industries. The purpose of this work was the evaluation of green extracting techniques and characterization of different bio-active compounds recovered from different matrices. The main goals were:  The development of an easy analytical approach for the identification and assay of Stevia sweeteners in commercially available soft drink based on liquid chromatography coupled to tandem mass spectrometry;  Extraction and characterization of active compounds from Olive (drupes and leaves) wastewaters, monitored by Liquid Chromatography (LC)-Electro Spray Ionization (ESI)-tandem mass spectrometry (MS/MS)  Extraction and characterization of lipids from alghe Schizochytrium sp. and identification of new adducts of fatty acids, monitored by Gas Chromatography/Liquid Chromatography (LC)-Electro Spray Ionization (ESI)-tandem mass spectrometry (MS/MS)
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    Advanced mass spectrometry-based strategies for the isolation and characterization of G protein-coupled estrogen receptor 1(GPR)
    (2014-11-28) Thangavel, Hariprasad; Gabriele, Bartolo; Sindona, Giovanni; Napoli, Anna
    Estrogen signaling plays a vital role in breast, ovarian and endometrial cancers. The actions of estrogen are mainly mediated by classical estrogen receptors, ERα and ERβ that belongs to the nuclear receptor superfamily. In recent years, a class of membrane-associated estrogen receptors are found to mimic the functions of classical ERs, including genomic as well as non-genomic signaling. These non-genomic signaling events include pathways that are usually thought of as arising from transmembrane growth factor receptors and G protein-coupled receptors (GPCRs). GPCRs belong to a superfamily of cell surface signaling proteins. GPCRs represent the most significant family of validated pharmacological targets in medical biology. A member of the GPCR family, named GPER, mediates rapid biological responses to estrogen in diverse normal and cancer cells, as well as transformed cell types. The identification and characterization of GPER will lead to understand the mechanisms underlying complex biological pathways and identify potentially new drug targets. Here, we proposed a novel gel-free method to isolate and enrich GPER from crude lysate using home-made hydroxyapatite column (HTP). The HTP eluate was subjected to cellulose acetate (CA) filteration, followed by on-membrane protein digestion with different proteases and analyzed by MALDI MS. GPER was identified by peptide mass fingerprinting (PMF) after intensive data analysis. Sequence analysis reports 3 potential N-glycosylation in GPER. We manually validated 2 out of 3 glycosylation sites in GPER from the obtained MS/MS data and also validated the glycan moieties predicted by Glycomod. This approach is the first of its kind to identify GPER and characterize post-translational modifications (PTMs) by MS-based proteomic analysis. The proposed method is simple, robust and unique with great reproducibility. Finally, we designed and synthesized polymer nanoparticles (NPs) in an effort to capture GPER with high affinity and selectivity from crude lysate. PNIPAm-based NPs were synthesized by a free radical precipitation polymerization method with no control over the functional monomer sequence. The NP binding affinity was evaluated against both truncated-GPER (short peptide epitopes) and GPER (whole protein). As the NPs were designed with complementary functionality against the peptides/protein, the NPspeptide/ protein binding will be through multipoint interactions. The initial qualitative results obtained by immunoblotting analysis revealed interesting hints on GPER’s competitive affinity towards NPs when probed against multiple antibodies. We anticipate to use this strategy as a sample purification step prior to MS-based proteomic analysis
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    New strategies for the synthesis of functionalized substituted bisphosphonates: chemistry and biological activity
    (2012-11-29) MULANI, Iqbal Mubarak; Sindona, Giovanni; Gabriele, Bartolo; Bartolino, Roberto
    The ever expanding cutting edge technologies in medicine for the benefit of society, the orthopedic branch is one among those significant branches in medicine pertaining to bone. Bisphosphonates (BPS) are being increasingly and successfully used to prevent bone fractures and the concerning problems of bone diseases such as Paget’s diseases, osteoporosis and tumour bone disease. In view of this specific problem, BPS are well established in the treatment of osteoclast -mediated resorbtive bone diseases including osteoporosis, Paget's disease and tumor-induced osteolysis. Recent studies suggest that, besides inhibiting bone resorbtion, BPS may also exert a direct antitumor effect, and this class of drugs has been shown to inhibit proliferation and to induce apoptosis in vitro in different human tumor cell lines. BPs are classified into two groups according to their chemical structure and mechanism of action: (i) non nitrogen containing BPS such as etidronate and clodronate that are of low potency and inhibit osteoclast function via metabolism into toxic ATPmetabolites and (ii) nitrogen-containing BPS (NBPS), such as pamidronate, alendronate, risedronate, ibandronate and zoledronate which is the most potent antiresorptive agent. Hence in present investigation we synthesized some several bisphosphonates bearing a substituted isoxazolidine ring by direct 1, 3- dipolar cyclization reaction in the absence of solvent and good yield under novel, promising and low cost microwaves catalysis. The method allows the simultaneous incorporation on the geminal position of the bisphosphonate framework, of basic nitrogen and of an oxygen atom, as third hook. The studies on the inhibitory potency of cyclic nitrogen containing bisphosphonates indicate that the presence of two geminal phosphonate groups is responsible for interaction with the molecular target. In addition, basic nitrogen in the heterocyclic side chain affects potency and its orientation is critical for effective inhibition of bone diseases. For the synthetic point of view, different aryl and alkyl substituents on the isoxazolidine ring prompt us to investigate the ring opening of these compounds through cleavage of the N-O bond. This strategy represents a novel access to new gem-hydroxyl bisphosphonates, bearing aryl substituents on the lateral chain. The reductive cleavage of the N-O bond in isoxazolidines represents a simple and direct access to N-substituted aminoalcohols, valuable intermediates in many synthetic strategies. Moreover, additional reaction path way have been envisaged leading to the formation of non-hydroxyl bisphosphonates.
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    Traceability of foodstuffs by high tech methodologies of mass spectrometry
    (2011-10-26) Naccarato, Attilio; Bartolino, Roberto; Gabriele, Bartolo; Sindona, Giovanni
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    Modern mass spectrometric applications in the structure and function evaluation of active principles
    (2011-10-26) Malaj, Naim; Gabriele, Bartolo; Sindona, Giovanni; Bartolino, Roberto
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    Qualita dell'olio e caratterizzazione molecolare di olea europea
    (2011-10-26) Bucci, Cristina; Sindona, Giovanni; Bartolo, Gabriele; Bartolino, Roberto
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    Different medicinal chemistry approaches towards the identification of novel targets in breast cancer
    (2013-12-02) Pisano, Assunta; Bartolino, Roberto; Gabriele, Bartolo; Sindona, Giovanni; Maggiolini, Marcello
    G protein-coupled receptors (GPCRs) belong to the largest family of cellsurface molecules representing the targets of approximately 40% of current medicinal drugs (Overington, J.P et al 2006). GPCRs are ubiquitous in mammalian (Bockaert, J. et al. 1999), regulate several physiological processes and play an important role in multiple diseases ranging from cardiovascular dysfunction, depression, pain, obesity to cancer (Rosenbaum D.M. et al. 2011). One member of this superfamily, named GPR30/GPER, mediates estrogen signaling in different cell contexts, leading to gene expression changes and relevant biological responses (Filardo E.J et al. 2000, Bologa C.G.et al. 2006, Maggiolini M. and Picard D. 2010). GPER acts by transactivating the Epidermal Growth Factor Receptor (EGFR), which thereafter induces the increase of intracellular cyclic AMP (cAMP), calcium mobilization and the activation of the phosphatidylinositol 3-kinase (PI3K) and the mitogen-activated protein kinases (MAPKs) (Maggiolini M. and Picard D. 2010). Moreover, the GPER-mediated transduction pathways activated by estrogens trigger the expression of a typical gene signature, including the expression of cfos and the gene encoding the connective tissue growth factor (CTGF), which are involved in the proliferation and migration of diverse cell types (Lappano R. et al 2012a, Madeo A. and Maggiolini M. 2010). On the basis of these findings, the first objective of the present study was the characterization of GPER from different points of view: GPERmediated signaling pathways and biological functions, selective ligands and molecular characterization of the receptors. In particular, the research project focused on:1. the transduction pathways by which the environmental contaminant Bisphenol A (BPA) influences cell proliferation and migration of human breast cancer cells and cancer-associated fibroblasts (CAFs); 2. the characterization of novel carbazole derivatives as GPER agonists in ER-negative breast cancer cells; 3. the isolation and characterization of GPER in estrogen-sensitive cancer cells by Mass Spectrometry. Additionally, the second section of this doctoral thesis was focused on the evaluation of the cytotoxic activity of novel synthesized compounds, given the interest and the need to discover new molecules against cancer. In particular, novel titanocene-complexes were studied evaluating their ability to elicit repressive effects on the growth of estrogen-sensitive breast cancer cells.
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    Synthesis of innovative material for food packaging
    (2013-06-30) Carchedi, Marisa; Bartolino, Roberto; Gabriele, Bartalo; Fazio, Alessia; Sindona, Giovanni
    Lo scopo del presente lavoro di tesi è la sintesi di materiali polimerici innovativi funzionalizzati con una porzione antiossidante legata alla catena laterale da utilizzare nella conservazione dei cibi, in particolar modo per prolungare la “shelf life” dei cibi della IV gamma cui appartengono frutta e verdura già lavata e tagliata, pronta all’uso. Generalmente questo genere di alimenti deperisce velocemente e ha una durata limitata a pochi giorni. L’ossidazione è una delle più importanti reazioni di degradazione dei cibi e poichè ne riduce la “shelf-life”, ne limita anche la conservazione con conseguente diminuzione delle vendite. L’active packaging prolunga la “shelf-life” dei cibi e allo stesso tempo ne migliora la sicurezza e le proprietà organolettiche. L’idea innovativa rispetto alle tecniche tradizionali è la preparazione di film bioattivi in cui la molecola antiossidante non è adsorbita sulla superficie del film con procedure di spraying, immersione o rivestimento, ma è legata covalentemente, tramite un linker, alla matrice polimerica. In questo studio è stata evidenziata la sintesi di un PET modificato innovato che reca una catena laterale funzionalizzata con una molecola antiossidante quale il ter-butilidrochinone (TBHQ) o l’idrossitirosolo (Tyr-OH). L’attività antiossidante dei monomeri di PET modificato funzionalizzati con il TBHQ e il Tyr-OH è stata testata tramite test del DPPH che ha confermato l’elevata capacità scavenger dei monomeri stessi. Un altro obiettivo del lavoro di ricerca è stata la caratterizzazione tramite spettrometria di massa di polimeri e copolimeri funzionalizzati. Questo studio è stato svolto in collaborazione con l’Università di Akron, Ohio, USA. Lo scopo del lavoro è stato sviluppare un protocollo di analisi di spettrometria di massa che fornisce informazioni riguardo la composizione dei poliesteri copolimeri, dei gruppi terminali, delle sequenze e della loro architettura. Più nello specifico, l’oggetto dello studio è stato il confronto tra il copolimero lineare poli(caprolattone)-poli(etilene glicole) (PCL-PEG) e l’omopolimero poli(caprolattone). Inoltre è stato condotto uno studio sull’energia di collisione necessaria alla frammentazione per il copolimero PCL-PEG, e gli omopolimeri PCL e PEG. Questo studio è stato condotto utilizzando spettrometri di massa MALDI Q/ToF e MALDI ToF/ToF/.Essendo questi polimeri ampiamente usati in moltissimi campi e per differenti applicazioni, in particolare applicazioni in campo biologico, è stato condotto uno studio di degradazione in mezzo acquoso per capire come e con quale velocità questi polimeri degradano e frammentano in presenza di acqua. Per effettuare questo studio i “frammenti” provenienti dalla degradazione sono stati separati per cromatografia liquida attraverso l’uso di uno strumento UPLC la cui uscita è accoppiata ad uno spettrometro di massa per poter facilmente individuare ed assegnare i vari frammenti.