Australia's marine environment offers a potential treasure trove of cures for human diseases, according to a University of Queensland researcher.
The Chemistry Department's Dr Mary Garson is currently investigating sponge chemicals known as alkaloids for potential anti-cancer, anti-malaria and anti-microbial applications.
The extracts are from sponge species found on the Great Barrier Reef near the University's Heron Island Research Station.
Dr Garson heads the Department's Marine Natural Products Group. Her Australian Research Council large grant-funded work focuses on isolating novel chemicals from marine invertebrates, determining the way atoms are arranged to make up the chemical structure and investigating how these chemicals are manufactured by the sponge.
The group has already identified many new species of marine invertebrates including sponges and flatworms in its search for novel chemicals.
Sponges have been targeted for investigation by the group because of their 'clean' nature - few organisms live or prey on them, and this suggests they produce chemicals to defend the sponge against larvae, algae and bacteria.
Because of these bioactive properties, the chemicals might also be useful to humans, Dr Garson said.
'Brightly coloured, soft-bodied, sessile invertebrates such as sponges, soft corals and molluscs would be an attractive food for fish and other carnivorous animals were it not for their ?chemical' defence,' Dr Garson said.
'They manufacture, or acquire from their diets, specific chemicals which are toxic or have anti-feedant or anti-fouling properties.'
Potentially useful compounds (small organic molecules) are isolated from the sponges collected under permit from the Great Barrier Reef Marine Park Authority. Using high-performance liquid chromatography to purify the chemicals followed by spectroscopic studies, sometimes in collaboration with the University's Centre for Magnetic Resonance, the researchers can determine the compounds' shapes and structures.
Compounds are refined into pure substances and their biological profile compared with compounds already known to be effective against disease or in other applications. This comparison helped researchers match compounds with particular applications, Dr Garson said.
Marine chemistry is a relatively new branch of chemistry, developed over the past 20 years. Dr Garson regularly works with scientists from other disciplines including biochemistry and marine biology.
Her group's work has also led to overseas collaborations with students from the United States, Philippines and Indonesia as well as Associate Professors Murray Munro and John Blunt from the University of Canterbury's Chemistry Department.
Dr Garson said a Fijian PhD graduate from the group had recently taken up a prestigious postdoctoral research fellowship at the National Cancer Institute in Washington DC.
World pharmaceutical, cosmetic and even paint companies are increasingly investigating natural environments for new substances beneficial to humans, a search known as 'bioprospecting'. The natural products also have potential applications in the paint, construction and cosmetic industries.
'Up to a quarter of the world's medicines derive from tropical plant products and microbes, including treatments for leukemia, heart disease, malaria and glaucoma,' she said.
'Life-saving immuno-suppressive, antibiotic and anti-parasitic drugs have also been developed from nature's materials.
'Nature is chemically innovative in a manner which makes synthetic organic chemists green with envy. The chemical structures of taxol, an anti-cancer drug from the Pacific yew tree, and of bryostatin, an anti-cancer compound developed from a moss-like marine animal, could never have been invented by medicinal chemists.'
Dr Garson said conservation was a very important consideration in bioprospecting marine environments because of the vast quantities of organisms which were sometimes required to extract tiny amounts of particular chemical compounds.
'A bioprospecting group based in the United States recently isolated 1mg of an anti-cancer compound from 450kgs of a 3 to 5mm-sized marine worm found in the Indian Ocean. I don't believe removing this amount of material, even for research purposes, can be justified,' Dr Garson said.
Further, the major biodiverse nations tended to be tropical developing nations which could be tempted to trade unrestricted access to natural products for large financial return, she said.
'Researchers from South-East Asia and Australia have worked together to develop protocols to prevent ?biopirating',' she said.
Consequently, research groups were investigating ways marine animals could be farmed (aquaculture) or grown in the laboratory.
'Large-scale harvesting of Australia's diverse marine resources is environmentally unfriendly. I believe that access to marine biodiversity must be regulated and that we need to find ways of growing marine organisms in the laboratory if the industry is to survive in the long term,' she said.
'We are trying to find ways of culturing sponges, and bacteria that live symbiotically with them, in the laboratory.
'In one of the sponges we study, the desired chemical is produced by microbes present in the sponge tissue. We are working on ways to separate the sponge and microbe cell types and grow the different types in the laboratory.
'In the future, it may also be possible to transfer genetic information from sponges into microbes, grow the microorganisms in the laboratory and isolate the sponge chemical from these.'
Dr Garson's group will stage a marine chemistry display as part of Expo Uni in room 220 of Chemistry Building at the University of Queensland, St Lucia, on May 17 and 18. For more information, contact Dr Garson (telephone 3365 3605). She will be overseas May 8-22.
