November 15 2004 at 07:12PM

Johannesburg - An indigenous plant used for centuries as a tonic and cancer treatment has been scientifically shown to have medicinal properties, researchers said on Monday.

Two independent studies at South African universities have demonstrated the stress-relieving and anti-oxidant properties of Sutherlandia frutescens, otherwise known as Cancer Bush, and "the one that dispels darkness", said Phyto Nova, a company that produces medicines from the plant.

"The plant is very variable. It grows wild all over the country," said botany professor and medicinal plant expert Ben-Erik van Wyk.

He said the particular strain used in the research had been developed by his company from plants that had been cultivated for medicine for many generations.

'It grows wild all over the country'
This strain (Sutherlandia SU1) is already available at pharmacies and health stores, costing about R35 to R50 for a month's treatment.

It had been tested and shown to be safe by the Medical Research Council, Van Wyk said.

Medicines made from the small red-flowered legume are used by people from many different cultures, and there are several companies that produce, and even export Sutherlandia products.

However, until these two studies, and another study by Canadian researchers were accepted for publication earlier this year, there was no scientific evidence of the plant's curative effect.

PhD student Carine Smith, and Professor Kathy Myburgh at the University of Stellenbosch, demonstrated that kankerbos could control levels of stress hormones in rats.

'The one that dispels darkness'
"The results show that Sutherlandia can reduce some of the negative physiological effects of chronic stress," said Myburgh.

She said this would explain its common use as a treatment for hypertension, anxiety, and depression.

It is known in Zulu and Xhosa as Unwele (hair) because it is believed to stop you "pulling out you hair" from distress. San cultures call it Insisa: "the one that dispels darkness".

Research at the pharmacology department at the University of Pretoria showed that the plant was also a powerful anti-oxidant.

Anti-oxidants are used to fight allergies and infectious diseases.

"This study indicates there is some validity in the belief that it can treat allergic reactions, auto-immune diseases and chronic infectious diseases," said departmental Professor Connie Medlen. - Sapa