Phytochemical study (isolation and chemical structure determination) of compounds and their analogues from greek plants (families Boraginaceae, Myrtaceae, Punicaceae, Lamiaceae) and their biological activity
Φυτοχημική μελέτη (απομόνωση και καθορισμός χημικής δομής) πυσιών και αναλόγων τους από ελληνικά φυτά (οικογένειες Boraginaceae, Myrtaceae, Punicaceae, Lamiaceae) και βιολογικές δράσεις
In the 1st part of the present PhD Thesis, the extracts of four Boraginaceae plantshave been studied:• cyclohexane extracts of cell culture and callus culture of Arnebia euchroma(13 constituents isolated, including 9 alkannin/shikonin derivatives along withsome glyceride mixtures)• cyclohexane extracts of hairy root culture of Lithospermum canescens (8secondary metabolites isolated, including 4 alkannin derivatives, 2shikonofurans and 2 sterols)• methanolic extract of Onosma erecta (aerial part) (7 secondary metabolitesisolated, including 4 new pyrrolizidine alkaloids (PAs), 1 new trihydroxy acidand 1 new acyloin)• methanolic extracts of Cynoglossum columnae: aerial part (5 secondarymetabolites isolated, including 3 known PAs, 2 known phenolic acid derivatives)& in vitro root culture (1 new furanonaphthoquinone isolated).The former two plants (Arnebia euchroma (Royle) Jonst. and Lithospermumcanescens (Michx.) Lehm.) are well-known medicinal plants in traditional Chinesemedicine and of significant commercial value. Therefore an attempt has been made, toinvestigate the possibility of the production of various important alkannin/shikoninmetabolites, in a more efficient biotechnological approach (parts 1.A, 1.B). The lattertwo plants (Onosma erecta L. and Cynoglossum columnae L.) are endemic plants inGreece and are studied phytochemically herein for the first time (parts 1.Γ, 1.).In part 1.E are presented the results of the GC-MS investigation of the PA profile oftwo endemic Greek Boraginaceae plants (Cynoglossum columnae and Onosmaleptantha), applying an established method, incorporating sample preparation,temperature program and column conditions.In part 1.ΣT the biological activities of the isolated alkannins/shikonins arepresented. All extracts and isolated compounds have been assayed in vitro for theircytotoxic, antibacterial, fungicidal and antileismanial activities, as well as in vivo fortheir antimalarial activity, showing a very interesting profile.In the 2nd part, the isolation of selected major constituents of four well-known Greekplants (belonging to the plant families Myrtaceae, Punicaceae and Lamiaceae) is brieflydescribed, followed by the bioassay results of their antiageing activity. Finally, theshort synthetic route attempted towards some potential antiageing ursolic acidsaponins, is also presented.