Friday, 26 August 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4 and Online Zoom Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Prof. Joanne Blanchfield; University of Queensland

Host: Prof. Kate Jolliffe

Title: Exploring traditional medicinal plants from the Northern Territory

Abstract: This research stems from a collaborative endeavour between UQ, Integria Healthcare®, Menzies School of Health, Traditional Homeland Enterprises, Tiwi Resources and the Hewitt Family. This work seeks to characterised the phytochemical composition of traditional medicines used by Aboriginal and Torres Strait islander communities of the Northern Territory.

In this talk the phytochemical components of two native Australian plant species will be discuss, Denhamia obscura (A. Rich.) Meisn. Ex Walp. and Acacia auriculiformis A. Cunn. Ex. Benth.  Both plants were collected in the Northern Territory, D. obscura from Deleye Outstation and A. auriculiformis from Larrakeyah, Darwin.

The leaves of Denhamia obscura are reported to be used by Indigenous communities to treat respiratory ailments,¹ and the highly coloured root bark is used as an oral anaesthetic² and fibre dye.  The hitherto unreported phytochemical composition of the leaves, seeds and root bark were explored and the crude extract and the four most abundant compounds from the root bark, tested for antimicrobial, anti-inflammatory, and cytotoxic properties.  A series of di and triterpenes were isolated including highly coloured compounds, maytenoquinone and pristimerin, and two previously unreported natural products. The crude extract and two of the diterpene compounds exhibited significant antimicrobial activity against Staphylococcus aureus and anti-inflammatory activity.

A. auriculiformis, more commonly known as the ‘ear-pod wattle’, is used traditionally by Aboriginal communities to prepare an antiseptic, soapy skin wash to relieve itching of the skin,^3,4 and as a fish poison.⁴ While the triterpene saponins and flavonoids present in this plant have been well studied, our investigation has focused on the alkaloids present in this plant. We report the structure elucidation of a number of alkaloids, including some highly unusual N-acylurea compounds using high resolution mass spectrometry and 1D and 2D ¹H, ¹³C and ¹⁵N NMR techniques.

Reference:

1. Puruntatameri J, Puruntatameri R, Pangiraminni A, Burak L, Tipuamantymirri C, Tipakalippa M, et al. Tiwi Plants and Animals: aboriginal flora and fauna knowledge from Bathurst and Melville Islands, northern Australia. Tiwi Land Council; 2001.
2. Appetiti E. Treatment of common ailments. In: Yaniv Z, Bachrach U, editors. Handbook of Medicinal Plants 2005.
3. Barr, A., Traditional bush medicines: an Aboriginal pharmacopoeia: Aboriginal Communities of the Northern Territory of Australia. Greenhouse Publications: Richmond, Vic., 1988.
4. Smith, N.M. J. Adelaide Bot. Gard. 1991, 14 (1), 1-65.