Evaluation of the anti-cancer potential of extracts of desert plants traditionally used as medicines by aboriginal people

It is well established that the ethnopharmacological approach to drug discovery is a very worthwhile pursuit, yielding a much higher hit rate than choosing plants at random. Aboriginal Australians maintain the oldest continuous culture on earth, but their wealth of phytochemical knowledge is largely unknown to the Western world. This study seeks to explore that knowledge with the imprimatur of Aboriginal knowledge custodians, to find a compound that may be of therapeutic use to cancer patients outside the Aboriginal communities. Our goals were also to empower Aboriginal people by validating their traditional knowledge and through profiting financially if commercial drugs are discovered. To this end, plants* identified by Aboriginal people as having medical properties were screened for their ability to inhibit the proliferation of cultured cancer cells. A panel of human cell lines representing colorectal (Caco-2), breast (MCF-7 and MDA-MB-468), prostate (PC-3 and DU-145), skin (MM-253) and lung (A549) cancers, was exposed to varying concentrations of methanolic extracts of these plants. After 48h culture, the MTT assay was used to assess inhibition of proliferation. Preliminary results indicate that at 1mg/mL concentrations, over half of the 30 extracts tested were able to inhibit the proliferation of at least one cell line by more than 50%. Importantly, there were differences between cell lines, indicating selectivity. Several extracts had IC₅₀ values of under 150µg/mL, a promising value given these were crude extracts and not pure compounds.

*Confidentiality agreements preclude the identification of plant names and sources.

Acknowledgements: Desert Knowledge CRC, Craig James, General Manager Commercialisation and Communication (DKCRC)