BALTIMORE-The herbal supplement gingko biloba appeared to lower the risk of ovarian cancer in an epidemiologic study, while laboratory studies showed that two of the herb's components caused ovarian cancer cells to stop growing. The studies were presented at the annual fall prevention meeting of the American Association for Cancer Research (abstract 3654).
Led by Bin Ye, MD and Daniel Cramer, MD, of Brigham and Women's Hospital, Boston, the researchers first examined the use of herbal and other supplements among 600 ovarian cancer patients and 640 healthy, matched controls. They found that about 10% of patients and 11.1% of controls had used a supplement, most frequently gingko biloba, echinacea, St. John's wort, ginseng, and chondroitin, at least weekly for 6 months or longer prior to their cancer diagnosis. The difference in overall use of these supplements was not significant. However, analysis of individual's herbal use showed that use of ginkgo biloba was significantly higher among women who did not have ovarian cancer. Those who took ginkgo had a 60% lower risk of developing the disease. The supplement appeared most effective in preventing ovarian cancers with the common, nonmucinous histology (65% to 70% risk reduction). "This suggests that women using gingko may be less likely to develop ovarian cancer," Dr. Ye said.
The investigators then conducted a series of in vitro studies with ovarian cancer cell lines. They found that among the tested flavonoids and terpenoids in gingko biloba, the compounds ginkgolide A and ginkgolide B caused significant cell cycle blockage in nonmucinous cells, inhibiting proliferation by up to 80%.