Oral Presentation Royal Australian Chemical Institute National Congress 2026

The hunt to uncover bioactives in Australian arid zone flora (136769)

Geordie M Thomson 1 , James J De Voss 1 , Craig M Williams 1 , Joanne T Blanchfield 1
  1. The University of Queensland, Brisbane, QLD, Australia

Natural products have been pivotal in the development of novel drug candidates, with nearly 70% of FDA-approved drugs from 1981-2019 being natural products, their derivatives, or mimics.1 Australian research in this field has led to the discovery of several promising drug candidates. Notable examples include ECB-23, an anticancer agent derived from the fruit of the rainforest tree Cinnamonum laubatii, and prostratin, an anti-HIV compound sourced from the tropical shrub Homalanthus nutans, which has been used by Samoan traditional healers.2,3 Despite the vast expanse of arid and semi-arid regions in Australia, which cover 70% of the country's land area, research has predominantly focused on tropical rainforests and coral reefs. The flora of these desert regions represent an underexplored reservoir of secondary metabolites with potential bioactivity. For instance, the diterpene stachyonic acid and the related basimarols A-C, isolated from the desert plant Basilicum polystachyon, have shown broad-spectrum antiviral activity against West Nile virus and human influenza viruses.4 To further investigate the phytochemistry of Australian desert plants, several species were collected from arid Central Queensland. These samples underwent ethanol maceration and were partitioned between chloroform and water. Various chromatographic techniques were employed for fractionation to isolate potential bioactive compounds. NMR spectroscopy, along with GC-MS and LC-MS, was utilised to identify compounds of interest. The iterative process of isolation, identification, and preliminary bioactivity testing is ongoing. To date, the desert shrub Nitraria billardierei has been investigated, yielding a number of rare flavonoid glycosides that have not previously been isolated from an Australian specimen. The isolation and structure elucidation of the flavonoid structures will be presented, along with progress toward both identifying the alkaloids present in the sample, and assessing potential bioactivity of the isolates.

  1. Newman, D. J.; Cragg, G. M. Natural Products as Sources of New Drugs over the Nearly Four Decades from 01/1981 to 09/2019. J. Nat. Prod. 2020, 83 (3), 770–803.
  2. Dong, L.; Gordon, V. A.; Grange, R. L.; Johns, J.; Parsons, P. G.; Porzelle, A.; Reddell, P.; Schill, H.; Williams, C. M. Structure and Absolute Stereochemistry of the Anticancer Agent EBC-23 from the Australian Rainforest. J. Am. Chem. Soc. 2008, 130 (46), 15262–15263.
  3. Gustafson, K. R.; Cardellina, J. H.; McMahon, J. B.; Gulakowski, R. J.; Ishitoya, J.; Szallasi, Z.; Lewin, N.; Blumberg, P.; Weislow, O. S.; Beutler, J. A.; Buckheit, R. W.; Cragg, G. M.; Cox, P. A.; Bader, J. P.; Boyd, M. R. A Nonpromoting Phorbol from the Samoan Medicinal Plant Homalanthus Nutans Inhibits Cell Killing by HIV-1. J. Med. Chem. 2002, 35 (11), 1978–1986.
  4. Tan, Y. P.; Houston, S. D.; Modhiran, N.; Savchenko, A. I.; Boyle, G. M.; Young, P. R.; Watterson, D.; Williams, C. M. Stachyonic Acid: A Dengue Virus Inhibitor from Basilicum Polystachyon. Chemistry - A European Journal 2019, 25 (22), 5664–5667.