Natural products isolation studies of Australian native plants

This thesis reports natural products isolation studies on a range of Australian native plant species. Pressurised hot water extraction (PHWE) utilising an unmodified household espresso machine was employed to facilitate the study of two Nothofagus species, sixteen fern species and three Myoporum species.
A review of secondary metabolites present in more than 100 fern species consumed in several countries in Asia was undertaken. Diplazium esculentum and Pteridium aquillinum are most widely consumed. A broad range of secondary metabolites have been isolated from these edible ferns. Several edible ferns have medicinal properties and most feature in traditional medicines.
Phytochemical screening of 16 native Australian fern species resulted in the isolation of 14 different natural products from 12 species. This included α- and γ-lactones, flavonoid glycosides, a dihydrobenzofuran neolignan, in addition to hydroxycinnamate/caffeic acid esters.
Natural products isolation studies of Nothofagus gunnii and N. cunninghamii were undertaken. The leaves of N. gunnii resulted in the isolation of stilbenes, flavonoids, sesquiterpenoids and chalcones. Four flavonoids were isolated from the leaves of N. cunninghamii. These natural products isolated were consistent with the respective subgenera Fucuspora and Lozophonia.
Natural products isolation study was undertaken of Myoporum insulare, M. parvifolium and M. montanum. As a result, two previously unreported furanosesquiterpenes and three γ-lactone-containing analogues, along with nine known furanosesquiterpenes and five other natural products were isolated. Overall, three distinct types of furanosesquiterpene structures were present in these three Myoporum species.
Four novel compounds, two prenylated flavonoids bearing unusual malonic acid groups, a prenylated flavonoid and an ent-labdane diterpenoid were isolated from Dodonaea filiformis and flowers of D. viscosa ssp. spatulata. An additional twelve known clerodane diterpenoids, ent-labdane diterpenoids and flavonoids were isolated. This study also revealed that the structure assigned to a compound previously isolated from D. viscosa was incorrect and that this molecule was actually a prenylated flavonoid containing a malonic acid moiety.