Georgetown University Medical Centre scientists have unravelled mystery surrounding the leaf extract of Ginkgo biloba tree in reducing aggressive cancer in animals.
Anticancer Research journal (Jan-Feb) features the study. The investigators reported that treating mice with this extract before and after implanting human breast or brain (glioma) tumours decreased expression of a cell receptor associated with invasive cancer.
An 80 percent decreased incidence was observed as long as the extract was used, compared to untreated mice, and also reduced the size of the brain tumours, but temporarily, and to a lesser extent.
Ginkgo biloba extract is a popular supplement that comes from the leaves of the Gingko tree, which is indigenous to Japan, Korea and China but can be found all over the world.
In the words of senior author, Vassilios Papadopoulos, DPharm, PhD, Director, Biomedical Graduate Research Organization and Associate Vice President of Georgetown University Medical Centre, "It is very encouraging that Ginkgo biloba appeared to reduce the aggressiveness of these cancers, because it suggests that the leaves could be useful in some early stage diseases to prevent them from becoming invasive, or spreading. But I must stress that this is a study in mice, and so we cannot say what anticancer effects, if any, Gingko biloba might offer humans. In fact, we have found that most life forms, including plants, insects, and animals, have receptors like these that help regulate growth. Accelerated growth requires production of new cell membranes, and one of the main components of membranes is cholesterol."
The researchers also knew that steroids help regulate brain function, and they found over-expression of PBR is also associated with a variety of neurological disorders.
On stressing the need for this new study he said that one aim of this new study, then, was to find whether other cancer cell lines also over-express PBR. The other part of the research was to see if Ginkgo biloba would show any anticancer effects on these cancer cell lines, and concluded that the extract did nothing to cancers that were not invasive, but significantly slowed the growth of aggressive cancer cells.
The next step of Papadopoulos is to examine the notion that a cancer diagnosis might increase production of stress steroids such as corticosteroids through PBR over-expression, and it is this stress that, in effect, pushes a tumour to become invasive. He says, "Ginkgo biloba could possibly reduce this stress by tamping down PBR."