Ginkgo biloba helping fight cancer

What prompts a cancer to become invasive?

A Georgetown University Medical Center researcher believes that one of the factors that causes a cancer to spread aggressively into tissue may be the way a person reacts to a cancer diagnosis. Furthermore, research has already revealed how an herbal extract may help prevent certain cancers from becoming dangerously invasive.

Early evidence

We’ve already seen evidence that ginkgo biloba extract may be an effective agent in managing ovarian cancer.

In the e-Alert “Silence Not Golden” (11/21/05), I told you about a Harvard study that examined herbal usage among 1,200 female subjects, half of whom were ovarian cancer patients. Researchers found that women who used ginkgo were much more likely to be in the healthy group. In fact, it appeared that when ginkgo was used for six months or longer, ovarian cancer risk was cut by as much as 60 percent.

The Harvard team backed up this research with a lab study in which results showed that a small amount of ginkgolide (the biologically active component of ginkgo biloba) stopped the growth of ovarian cancer cells.

Two steps up

Obviously, further studies will be needed to confirm the Harvard findings. And recent research from Georgetown University may provide the next few steps toward confirmation.

For two decades, Georgetown researchers have been studying a molecule known as PBR. This protein molecule plays an important role in drawing cholesterol into a cell where it’s used to produce steroids. And for our purposes today, forget all the negative reports you’ve heard concerning steroid use in professional sports. Steroids are regulatory hormones that a cell needs for proper growth.

The Georgetown research showed that PBR is over-expressed by some highly invasive cancers, including certain brain cancers, breast, colon and prostate cancers. PBR over-expression is also linked to some neurological disorders, so Dr. Vassilios Papadopoulos (vice president of the Georgetown University Medical Center) decided to test ginkgo on PBR production.

Dr. Papadopoulos’ team took breast cancer cells that over-expressed PBR and implanted them in mice. After a 30-day treatment with ginkgo extract, tumor size was reduced by 35 percent compared to mice that didn’t receive ginkgo.

In a more recent lab study from the Georgetown team, ginkgo extract had no effect on non-invasive cell cancer lines, but the growth of aggressive cancer cells was significantly slowed by the extract.

A Georgetown press release states that Dr. Papadopoulos is currently examining a theory that a cancer diagnosis might boost the production of stress steroids through PBR over-production. He believes such stress may prompt a tumor to become invasive, and adds, “Ginkgo biloba could possibly reduce this stress by tamping down PBR.”

Acid test

All of these cancer studies that involve ginkgo are strictly preliminary, so it will be some time yet before a clear picture begins to emerge.

I expect that most HSI members are aware that ginkgo biloba is well known as a potential memory enhancer and an aid for cognitive function that might even be effective in treating the early symptoms of Alzheimer’s disease.

If you’re thinking of supplementing with ginkgo, keep in mind that many alternative practitioners believe the recommended daily dosage of 120 mg is too low, and that the dosage should be 240 mg or more per day. The optimal dosage for any individual should be determined by weighing other health factors, other supplements or drugs being used, and only after consulting a doctor or medical professional.

Also note that ginkgo may prompt gastrointestinal bleeding. Apparently this bleeding is slight, and usually happens when ginkgo is taken with other agents that are also known to prompt such bleeding, like aspirin or the anticoagulant drug warfarin. So for most people, bleeding shouldn’t be a problem. However, there are other ginkgo side effects, including headaches and skin irritations.

The culprit in these cases is ginkgolic acid, a toxic compound. It’s generally accepted that five ppm (parts per million) is a safe maximum level for this acid. But some supplement manufacturers don’t list ginkgolic acid on their labels, so be sure to read content labels carefully.

Sources:
“Ginkgo Biloba and Ginkgolides as Potential Agents for Ovarian Cancer Prevention” Abstract #3654, Presented 10/31/05, American Association for Cancer Research’s 4th annual Frontiers in Cancer Prevention Research, aacr.org
“Ginkgo Biloba Extract: More than Just for Memory?” Georgetown University Medical Center press release, 2/23/06, eurekalert.org