Ginkgo Prevents Ovarian CancerGinkgo Use in Ovarian Cancer Prevention
Ye B, Aponte M, Dai Y, et. al. Ginkgo biloba and ovarian cancer prevention: epidemiological and biological evidence. Cancer Lett. Jun 18, 2007;251(1):43-52.
Ginkgo (Ginkgo biloba) leaves contain flavonoids and terpenoids with antioxidant and anti-lipoperoxidative effects that are important in the chemoprevention of cancer. In vitro evidence suggests that ginkgo may reduce the growth of human breast cancer cells and has significant anti-proliferative and cytotoxic effects on human hepatocellular carcinoma cells. In vivo studies show that ginkgo may promote apoptosis through caspase-3 activation in oral cavity cancer cells and prevent benzo[a]pyrene-induced forestomach carcinogenesis. This study examines the possible role of ginkgo in the prevention of ovarian cancer through an examination of epidemiological and biological data.
The epidemiological portion of this study is part of a population-based case control study of ovarian cancer conducted in New Hampshire and eastern Massachusetts between July 1998 and July 2003. A total of 668 cases of epithelial ovarian cancer found in cancer registries and tumor boards and 721 controls found through town books in Massachusetts and driver's license lists in New Hampshire are included. The controls were matched to the cases in terms of age and residence. The subjects were asked about medical and family histories and dietary supplement use during interviews. The subjects also completed a dietary questionnaire and provided blood samples. For the in vitro portion of the study, various types of human ovarian cancer cell lines were used.
The regular use of over 30 separate dietary supplements was reported by the cases and controls. Ginkgo was one of the top five most-used dietary supplements. It was the only dietary supplement associated with influencing ovarian cancer risk. Thirty controls (4.2%) and 11 ovarian cancer cases (1.6%) regularly used ginkgo supplements for at least six months (95% CI and adjusted RR=0.41 [0.21, 0.84], P=0.01). The use of ginkgo by itself was associated with a decreased risk of ovarian cancer (95% CI and adjusted RR=0.36 [0.14, 0.91], P=0.03). The inverse association between ovarian cancer and ginkgo use was limited to non-mucinous types of ovarian cancer (95% CI and adjusted RR=0.33 (0.15, 0.74), P=0.007).
The standard ginkgo extract showed significant inhibition of OVCA429 ovarian cancer cells (P<0.01) and less significant inhibition of HOSE and RMUG-L (mucinous type) ovarian cancer cells. Ginkgolide A and ginkgolide B demonstrated significant inhibition of OVCA429 ovarian cancer cell proliferation (P<0.0001), reducing proliferation by about 60%, compared with controls. Ginkgolide A and ginkgolide B also inhibited the proliferation of other non-mucinous type ovarian cancer cell lines, including OVCA420 and OVCA433, showing about 30-40% inhibition, compared with controls. The compounds had very little effect on the proliferation of mucinous type RMUG-L and HOSE-E6E7 ovarian cancer cells. Treatment with ginkgolide B significantly increased the G0/G1 phase DNA in OVCA429 ovarian cancer cells (P<0.01) and reduced S-phase DNA (P<0.01). A reverse effect was observed in mucinous RMUG-L cells. Treatment with ginkgolide B significantly reduced G0/G1 phase DNA and increased S-phase DNA in RMUG-L ovarian cancer cells. Treatment of OVCA429 ovarian cells with ginkgolide A resulted in an increase in G0/G1 DNA and decreased S-phase DNA contents. The researchers found ginkgolide A and B in the blood sample of a woman who had taken ginkgo for 136 months.
The biological assay and epidemiological evidence show that the regular use of ginkgo supplements is associated with a decreased risk of developing ovarian cancer, particularly non-mucinous type ovarian cancer. This effect appears to be mediated through the anti-proliferative effects of ginkgolides A and B a