Marine environment is the biggest still unknown source of chemicals of our Earth. Oceans and seas actually cover more than 70% of our planet’s surface and contain a huge bio- and chemical diversity just partially explored at the moment. The variety of marine-derived compounds can exert different bioactivities useful in pharmaceutical and nutraceutical fields to fight or support the therapies of human pathologies still considered incurable or rare, or new diseases. The first aim of this investigation was the isolation, purification and structure elucidation of secondary metabolites of the fungus Aspergillus elegans KUFA 0015, isolated from the marine sponge Monanchora unguiculata, collected from the coral reef in Kram Island, Chonburi Province, Thailand. The second aim was the evaluation of the biological properties of the isolated compounds starting from the antibacterial activity against Gram-positive and Gram-negative bacteria. The isolation and purification were carried out using several chromatographic techniques, as preparative thin layer chromatography (TLC) and liquid chromatography, and Mass Spectrometry and NMR Spectroscopy. This investigation led to the isolation from the crude EtOAc extract from the culture of the fungus, A. elegans KUFA 0015 five metabolites. The structures of the isolated compounds were established on the basis of extensive analysis of the 1D and 2D NMR spectra and High Resolution Electrospray Ionization Mass Spectra (HRESIMS) data as well as by comparison of their 1H and 13C NMR data and other physical data with those reported in literature. The instrumental analysis led to the identification of five previously known compounds, including ochratoxin A methyl ester (I), ochratoxin B (II), viomellein (III), 6-hydroxy-3-methyl-3,4-dihydroisocumarin-5-carboxylic acid (IV) and rubrosulphin (V). The intended evaluation of the antibacterial activity against Gram-positive and Gram-negative bacteria has not been carried out due to the emergency of COVID-19 pandemia, as a result of which the faculty was closed and the work suspended.
L’ambiente marino è la più grande fonte di sostanze chimiche ancora sconosciuta della Terra. Gli oceani e i mari infatti coprono più del 70% della superficie del nostro pianeta e contengono una immensa bio- e chemo- diversità finora esplorata soltanto parzialmente. La varietà di composti che possono derivare dal mare può avere diverse attività biologiche utili nei campi farmaceutico e nutraceutico per combattere patologie umane ancora oggi considerate incurabili o rare, o nuove malattie. Il primo scopo di questa ricerca è stato l’isolamento, la purificazione e l’elucidazione delle strutture di metaboliti secondari del fungo A. elegans KUFA 0015, isolato dalla spugna marina Monanchora unguiculata, raccolta dalla barriera corallina nell’isola Kram, nella provincia Chonburi, in Tailandia. Il secondo scopo è stato quello di valutare le proprietà biologiche dei componenti isolati partendo dallo studio dell’attività antibatterica contro batteri Gram-positivi e Gram-negativi. L’isolamento e la purificazione sono stati svolti usando diverse tecniche cromatografiche, come la cromatografia su strato sottile (Thin Layer Chromatography, TLC) preparativa, la cromatografia liquida, e la spettrometria di massa o la spettroscopia NMR. Lo studio ha permesso di isolare dall’estratto grezzo di acetato di etile, dalla coltura del fungo A. elegans KUFA 0015, cinque metaboliti. Le strutture dei composti isolati sono state stabilite sulla base di una approfondita analisi degli spettri NMR 1D e 2D e di massa, ottenuti con ionizzazione elettronica ad alta risoluzione, e attraverso la comparazione dei dati 1H e 13C NMR e di altre caratteristiche fisiche a quelli riportati in letteratura. L’analisi strumentale ha portato a identificare cinque composti che sono già noti in letteratura, quali ochratossina A estere metilico, ochratossina B, viomelleina, 6-idrossi-3-metil-3,4-diidroisocumarin-5-acido carbossilico e rubrosulfina. Lo studio dell’attività antibatterica contro batteri Gram-positivi e Gram-negativi previsto non è stato portato a termine a causa dell’emergenza della pandemia COVID-19, a seguito della quale la facoltà è stata chiusa e il lavoro sospeso.
Metaboliti Secondari Biologicamente Attivi Estratti dalla Coltura del Fungo Marino Aspergillus elegans KUFA 0015
MARENGO, ALESSIA
2019/2020
Abstract
Marine environment is the biggest still unknown source of chemicals of our Earth. Oceans and seas actually cover more than 70% of our planet’s surface and contain a huge bio- and chemical diversity just partially explored at the moment. The variety of marine-derived compounds can exert different bioactivities useful in pharmaceutical and nutraceutical fields to fight or support the therapies of human pathologies still considered incurable or rare, or new diseases. The first aim of this investigation was the isolation, purification and structure elucidation of secondary metabolites of the fungus Aspergillus elegans KUFA 0015, isolated from the marine sponge Monanchora unguiculata, collected from the coral reef in Kram Island, Chonburi Province, Thailand. The second aim was the evaluation of the biological properties of the isolated compounds starting from the antibacterial activity against Gram-positive and Gram-negative bacteria. The isolation and purification were carried out using several chromatographic techniques, as preparative thin layer chromatography (TLC) and liquid chromatography, and Mass Spectrometry and NMR Spectroscopy. This investigation led to the isolation from the crude EtOAc extract from the culture of the fungus, A. elegans KUFA 0015 five metabolites. The structures of the isolated compounds were established on the basis of extensive analysis of the 1D and 2D NMR spectra and High Resolution Electrospray Ionization Mass Spectra (HRESIMS) data as well as by comparison of their 1H and 13C NMR data and other physical data with those reported in literature. The instrumental analysis led to the identification of five previously known compounds, including ochratoxin A methyl ester (I), ochratoxin B (II), viomellein (III), 6-hydroxy-3-methyl-3,4-dihydroisocumarin-5-carboxylic acid (IV) and rubrosulphin (V). The intended evaluation of the antibacterial activity against Gram-positive and Gram-negative bacteria has not been carried out due to the emergency of COVID-19 pandemia, as a result of which the faculty was closed and the work suspended.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/11510