Taking medicine back to nature
greentea.jpg
Green tea is just one of the phytochemicals being
investigated by WA scientists.
Image by iStockphoto

Ancient cultures never doubted the healing powers of plants and animals. A sick person turned to their local medicine man, wise woman or witch doctor, who would mix a treatment made from local plants, bark, herbs and perhaps even parts of insects, amphibians, reptiles and birds.

For thousands of years before willow bark was used to create aspirin and the opium poppy to make morphine people knew about their pain-relieving properties.

Now phytochemicals are again high on medical science’s priority list.

You would have to live at the bottom of the ocean to have missed the glowing reports about the omega-3 fatty acids in fish oil. And don’t be too quick to recoil at early man’s reptile fascination: US scientists are studying the proteins in crocodile and alligator blood for their powerful infection-fighting properties.

Curcumin from tumeric, capsaicin from chillies, resveratrol from grapes, quercetin from strawberries and epigallocatechin gallate (EGCG) from green tea are among the thousands of compounds being investigated for their powerful therapeutic benefits – and Western Australian scientists are at the forefront of some of this research.

Dr Jonathan Hodgson from the Centre for Food and Genomic Medicine, based at the WA Institute for Medical Research, is internationally recognised for his population-based findings on the benefits of green tea.

“Drinking green tea to promote good health goes back 2,000 years,” he says.

“Ancient people recognised the efficacy of phytochemicals – those nutrients in plants that may not be essential for survival but certainly may be helpful in certain situations. But recently scientists have said, ‘Where is the evidence of these health benefits?’

“Our studies have certainly found evidence of the short-term cardiovascular benefits (of drinking green tea) and our latest study is looking for benefits in the longer-term.”

Renowned Alzheimer’s researcher Ralph Martins does not need to be convinced of the potential of certain natural compounds. He is about to launch a three-year study into the synergistic effects of a cocktail containing curcumin, fish oil, green tea and lipoic acid, which is found in liver, spinach and broccoli.

Importantly, he says, funding bodies are also becoming more open-minded about so-called “alternatives”.

“The benefits of certain plants and animals have been known for centuries, but this is now being acknowledged by the mainstream,” he says. “The fact that the NHMRC (National Health and Medical Research Council) has recognised this with a grant of nearly half a million dollars for our study is a sign that they are being accepted.”

Professor Martins, of Edith Cowan University, and collaborator Dr Matthew Sharman believe that, in combination, the powerful antioxidants in their study could help to suppress the toxic form of a protein called beta amyloid which causes Alzheimer’s disease.

“In my very first published paper in 1986 we were the first in the world to show that in the case of Alzheimer’s the brain was being oxidised,” he says.

“Over the years we have identified the best antioxidants, and these are it. Lipoic acid is metal-chelating and beta amyloid binds with copper and zinc. Fish oil we probably have the most excitement about. A high cholesterol diet has shown to be associated with a high level of beta amyloid and a high-fish diet is shown to suppress this build up.”

He says Dr Sharman had concluded a major study to find the “magic dose” that will ensure these phytochemicals cross the blood-brain barrier without toxic side-effects.

“We want to optimise beneficial effects. We want the results to be something that is really profound.”

At the University of Western Australia, too, researchers have been focusing on dosage of these natural compounds which, in their pure form, are often poorly absorbed by the body.

Nigel Clifford of the Centre for Strategic Nano-Fabrication, has come up with a novel method to deliver curcumin, the curry spice credited with lowered rates of certain cancers in Asia compared with the West.

Mr Clifford’s mesoporous silica capsules are impregnated with tiny pores through which the curcumin is released slowly, enabling it to remain in the body at a consistent level.

In the past month his paper on the nano-invention has become the most downloaded publication on the online version of the Materials Chemistry journal.

Professor Colin Raston, director of the centre, says the work could give doctors the ability to deliver curcumin and other drugs in a less toxic way with fewer side effects.

Growing bacterial resistance to antibiotics – resulting in the ‘superbugs’ affecting many hospitals – has also renewed medicine’s interest in natural antiseptics such as tea tree oil.

Numerous studies by Professor Tom Riley of UWA Microbiology have shown the traditional Aboriginal bush medicine has powerful anti-microbial qualities.

It is important, says Professor Riley, for the oil to be seen as “bona fide”, far removed from the “realms of quackery”.  

Ready acceptance of tea tree oil by medical science may not be far off.

But, Dr Hodgson says, it will take researchers many years to screen the hundreds of thousands of combinations of natural compounds – whether from spinach, sea sponges or snakes – that could benefit humankind.

“What is clear is that we are still only scratching the surface of the potential of plants and I’m sure there are many valuable bioactive compounds still to be discovered,” he says.


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