​Breast cancer is the most diagnosed form of cancer among women and also responsible for the most cancer-related deaths among women.

However, in the near future Fynbos could help curb it, says Dr Koch Visser of the Department of Biochemistry at Stellenbosch University (SU). In a recent doctoral study at SU, he found that the Fynbos plant, Cyclopia, used to make honey bush tea, may help stop the development of breast cancer. 

Visser specifically looked at the effect of Cyclopia extracts on breast cancer cells to figure out the possible molecular mechanism behind this effect. 

He used tissue culture techniques to test the effect of extracts obtained from dried plant material. With tissue culture, commercially available cancer cells, grown in a laboratory and able to multiply indefinitely, are used for testing. According to Visser, tissue culture is particularly useful to figure out molecular mechanisms because it is easier to manipulate. 

He adds that it also serves as a form of control because researchers at other institutions use the same cells and results are therefore comparable. 

"We found that Cyclopia extracts prevent the estrogen-induced growth of breast cancer cells by targeting and inhibiting estrogen receptor subtypes that promote the growth of these cells," says Visser. 

Estrogen, the female hormone, performs its physiological function through these receptor subtypes. 

"The fact that Cyclopia extracts target the receptor subtypes sheds light on the possible mechanism by which the extracts regulate the growth of breast cancer cells," says Visser. 

"I'm particularly excited about the discovery that Cyclopia extracts are absorbed through the digestive tract, while remaining nontoxic even at high concentrations. Also, the extracts do not stimulate the growth of the uterus." 

Visser says this finding is important because several studies have shown that certain drugs used to treat breast cancer increase the risk of cancer of the uterus. 

"There's a possibility that this research could offer respite to women who may be diagnosed with breast cancer in future, especially considering the global need to better understand the development and progression of this disease in order to treat it effectively." 

Visser says Cyclopia, which is freely available and sold commercially as Honeybush, contains active compounds or "plant estrogens" that can mimic or counter the effect of our own hormones. 

He emphasises the importance of identifying these active compound (s) so that intake can be regulated and consumers can know they are using the right dosage of the active ingredients. 

"At this stage it is still too early to say with certainty what the final form of the medicine made from Cyclopia will be and how often it will have to be used." 

Visser says women aged 50 and older may benefit from research on Cyclopia because they have a greater chance of developing breast cancer. They are also more likely to use hormone replacement therapy because the natural production of estrogen decreases dramatically during menopause, he adds. 

"While hormone replacement therapy is usually prescribed for the treatment of symptoms associated with menopause, it can contribute to the development of breast cancer." 

Visser notes that Cyclopia extracts may be used as an alternative to traditional hormone replacement therapy.

Although the results of his study seem promising, Visser says that this type of research is still in its infancy. 

"We are confident that we are on the right track and that we can contribute to the pool of knowledge about how breast cancer develops." 

Visser says research at other institutions such as the Medical Research Council, Cape Peninsula University of Technology, North-West University, and the University of the Western Cape has shown that Cyclopia extracts may also help against skin, liver and oesophagus cancer.

• Dr Koch Visser is a postdoctoral fellow in the Department of Biochemistry at Stellenbosch University. ​