African tree compound patented in the US

AFRICAN ROOT COULD BE CURE FOR ATHLETE'S FOOT

Reports by Steve Connor, Science Editor in Washington

The Independent, London, 21 February 2000

Drug prospectors who explore the natural world for new medicines have discovered a potent substance in the roots of an African tree which could be used to treat fungal infections such as athlete's foot and thrush.

Studies have shown that the chemical derived from the tree is more powerful than current anti-fungal drugs. Clinical trials are expected to begin within the next year on patients suffering from serious microbial infections.

The discovery, announced at the annual meeting of the American Association for the Advancement of Science in Washington DC, is one of the first to emerge from a renewal of scientific interest in the extraction of new medicines from natural products.

Kurt Hostettmann, head of the school of pharmacology at the University of Lausanne in Switzerland, said an initial safety trial on about 20 volunteers with fungal infections of the skin, as well as tests on laboratory animals, have demonstrated the drug's potential.

"We have just got a patent in the United States and an American company is developing it. We hope it will come on the market in the next couple of years," Professor Hostettmann said.

Under the terms of an international treaty on biodiversity, a small percentage of the profits from new drugs extracted from the Third World has to be ploughed back into research within the country of origin. "We want to give back to the traditional healers the information we get from studying the plant," he said.

The emergence of drug-resistance fungal microbes and the difficulty of treating internal attacks, particularly in the eye, has made the development of new treatments increasingly important.

Six trees belong to the species Swartzia madagascariensis growing in Zimbabwe had to be destroyed to produce just 50g of the anti-fungal agent but Professor Hostettmann said it should soon be possible to synthesise the active ingredients in the laboratory. "We have done plenty of in vivo testing on mice and our compound was much more active than all existing compounds on the market. As well as Candida [thrush], it has been tested against 200 different fungi," he said. "We are also testing it for treating fungal infections of the eyes because there is almost no drug for treating eye infections. Many Aids patients suffer from such eye problems."

The scientists believe the substance, which is only found in the tree's roots, protects the plant from soil fungi which would otherwise rot the underground vegetable tissues.

Gordon Cragg, a scientist in the natural products division of America's National Cancer Institute, said the destruction of wild habitats both on land and in the oceans is rapidly eroding the range of natural sources of new drugs.

"We tend to forget the destruction going on in the marine environment which is a tremendous source of interesting chemical entities for drug discovery. The loss of biodiversity is a very real threat," Dr Cragg said.