Natural Products Isolated from Endemic Tasmanian Vascular Plants

Abstract

Tasmania is the south-eastern island state of Australia. It is geographically isolated and is recognised for both its rich diversity of plant species and high degree of endemism. Although 530 endemic Tasmanian vascular plant species are known, natural products have only been isolated from 27 of these species (~5.1 %), representing 3 classes (Dicotyledonae, Monocotyledonae, and Gymnospermae), 12 families, and 14 genera. Terpenoids, flavonoids, and alkaloids are the major classes of compound that have been isolated from these species. This report provides the first review of the natural products isolated from endemic Tasmanian plant species and covers ~70 years of research in this area.

Development and Applications of Water‐based Extraction Methods in Natural Products Isolation Chemistry

“…It is also likely that p-hydroxyacetophenone (24), which was isolated from the related Proteaceae species Agastachys odorata via percolation with methanol is another possible artefact of isolation potentially resulting from hydrolysis and decarboxylation. [35,36] It should be noted that arbutin glycosides were not identified in either of these previous studies of B. montana and A. odorata. [34,35] However, the earlier work focusing on B. montana reported the isolation of various alkaloids, which were not found in the PHWE study.…”

“…[35,36] It should be noted that arbutin glycosides were not identified in either of these previous studies of B. montana and A. odorata. [34,35] However, the earlier work focusing on B. montana reported the isolation of various alkaloids, which were not found in the PHWE study. 33 This technique also enabled the study of three endemic Tasmanian Lomatia species (L. tasmanica and L. tinctoria, and L. polymorpha).…”

“…Earlier studies of B. montana reported the isolation of an unusual γ-lactone alkaloid (22), [34] however, this compound is likely an artefact of the isolation formed by the reaction of arbutin derivative 13 and ammonia present in the extraction solvent. [35] In addition, methyl benzoyl acetate 23 was isolated in earlier studies of B. montana that employed methanol as an extraction solvent ( Figure 7). [33] This appears to be an artefact resulting from transesterification during the long extraction times involved.…”

“…Notably, (-)-meranzin (33) (100 μM) showed NQO1 inhibitory activity comparable to the known potent NQO1 inhibitor dicoumarol. [38] PHWE (35% v/v EtOH/ H 2 O) was used to obtain bruceol (35), isobruceol (36), hydroxyeriobrucinol (37; 0.44% w/w), and isoimperatorin (38; 0.018% w/w) from Philotheca brucei (Figure 10). [39] Significant quantities of eucalyptol were also identified in the extract.…”

RACI and Academy of Science Awards 2017–18

“…Nonetheless, a wide variety of products, including furans, phenolics, pyrones, quinones, alkaloids, terpenoids, steroids, and polyynes have been characterised. [5] Martina Stenzel (UNSW) was awarded the 2017 H. G. Smith Medal of the RACI. In a Review, she describes how therapeutic proteins have made an impact in the drug market, but since proteins are subject to quick hydrolytic degradation or denaturation, they require a protective layer.…”