Φυτοχημική μελέτη του ελληνικού ενδημικού φυτού Inula subfloccosa Rech. f. (Asteraceae)

Στα πλαίσια της παρούσας μεταπτυχιακής εργασίας, εξετάστηκε η χημική σύσταση του ενδημικού στην ανατολική Ελλάδα είδους Inula subfloccosa της οικογένειας Asteraceae. Υπέργεια τμήματα της I. subfloccosa, αποξηραμένα και αδρομερώς τεμαχισμένα, εκχυλίστηκαν εξαντλητικά με οργανικούς διαλύτες και το εκχύλισμα που προέκυψε υποβλήθηκε σε σειρά χρωματογραφικών διαχωρισμών. Απομονώθηκαν συνολικά δέκα μεταβολίτες από τους οποίους μέχρι τώρα έχουν ταυτοποιηθεί οι εννέα, οι οποίοι στο σύνολο τους ανήκουν στην κατηγορία των σεσκιτερπενικών λακτονών. Συγκεκριμένα, τέσσερις έχουν σκελετό ευδεσμανίου (ισοαλαντολακτόνη, ιβαλίνη, ασπεριλίνη, ισοτελεκίνη), τέσσερις γουαϊανίου (4α,5α-εποξυ-10α,14Η-1-επι-ινουβισκολίδιο, 1-επι-ινουβισκολίδιο, ινουβισκολίδιο και 1α-υδροξυ-γουαϊα-4(15),11(13)-διεν-8α,12-ολίδιο) και ένας ψευδογουαϊανίου (2-δεσοξυ-4,10-επι-πουλχελίνη). Ο μεταβολίτης 8,1α-υδροξυ-γουαϊα-4(15),11(13)-διεν-8α,12-ολίδιο απομονώθηκε για πρώτη φορά από εκπρόσωπο του γένους, ενώ ο μεταβολίτης 9,2-δεσοξυ-4,10-επι-πουλχελίνη αποτελεί νέο φυσικό προϊόν.The genus Inula L. (Asteraceae) comprises c. 90 species, about 19 of which are native to Europe. They are perennial herbs, rarely shrubs, sometimes with an unpleasant smell. Several Inula species are used as traditional herbal medicines to treat a broad spectrum of disorders, mainly respiratory, digestive, inflammatory, dermatological, as well as microbial infections. Sesquiterpenes, mostly sesquiterpene lactones including eudesmane, guaiane, pseudoguaiane and germacrane derivatives are characteristic components of Inula species, many of which have exhibited a wide range of biological activities, particularly anti-tumor and anti-inflammatory. The chemical profile of Inula subfloccosa Rech. f., an endemic plant of Greece that is restricted to cipolin and marbles, has not been previously studied. Aerial parts of I. subfloccosa were collected during the flowering period. The air-dried plant material was exhaustively extracted with CH2Cl2/MeOH at room temperature and the resulting crude extract was fractionated with a series of chromatographic separations. So far, 9 sesquiterpene lactones have been isolated from the aerial parts of I. subfloccosa. Detailed analyses of 1D and 2D NMR and MS data led to the identification of four eudesmanolides, four guaianolides, and one pseudoguaianolide. Among the isolated compounds, the bioactive metabolites 4α,5α-epoxy-10α,14H-1-epi-inuviscolide and isoalantolactone were the major constituents, whereas the pseudoguainolide derivative is a new natural product

New C15 Acetogenins from Two Species of Laurencia from the Aegean Sea

The chemical diversity of the approximately 1,200 natural products isolated from red algae of the genus Laurencia, in combination with the wide range of their biological activities, have placed species of Laurencia in the spotlight of marine chemists’ attention for over 60 years. The chemical investigation of the organic (CH2Cl2/MeOH) extracts of Laurencia microcladia and Laurencia obtusa, both collected off the coasts of Tinos island in the Aegean Sea, resulted in the isolation of 32 secondary metabolites, including 23 C15 acetogenins (1–23), 7 sesquiterpenes (24–30) and 2 diterpenes (31 and 32). Among them, six new C15 acetogenins, namely 10-acetyl-sagonenyne (2), cis-sagonenyne (3), trans-thuwalenyne C (4), tinosallene A (11), tinosallene B (12) and obtusallene XI (17), were identified and their structures were elucidated by extensive analysis of their spectroscopic data. Compounds 1–3, 5–11, 13 and 15–32 were evaluated for their antibacterial activity against Staphylococcus aureus and Escherichia coli