'Cancer Bush' May Cut Prostate Risk

CHICAGOSutherlandia, an African herb, could be the next best herb in prostate cancer prevention. Dennis Lubahn, Ph.D., professor of biochemistry and child health, National Institutes of Health (NIH) Botanical center, University of Missouri-Columbia, noted mice studies are promising, showing the herb can block prostate cancer formation.

In a talk he gave at the eighth annual Natural Health Research Institute (NHRI) symposium, Lubahn said Lessertia furtescens (Sutherlandia) is an adaptogen that has been know as "Cancer Bush" in traditional medicine to improve the immune system, manage stress, reduce symptoms of HIV infection, reduce cancer risk and treat diabetes symptoms. However, he noted no modern clinical evidence shows Suterlandia's benefits to human. A 2007 study did show it was safe for healthy adults at a 400-mg/d dose for three months (PLoS Clin Trials. 2007 Apr 27;2(4):e16).

While Lubahn noted few botanical compounds have been shown to affect prostate cancer, he said the NIH Botanical Center plans to continue study of Sutherlandia prostate cancer treatment.

NIH has previously found genistein, the major phytoestrogen in soy, to be a possible prostate cancer treatment. he said epidemiological studies show genistein lowers the incidence of breast and prostate cancer. In Asia, where the population eats 20 to 80 mg/d of genistein, they have four to five times lower incidence of breast cancer than in the United States, where the population eats 1 to 3 mg/d. The United States also has four to five times the prostate cancer mortality rate of Japan; perhaps this is due to genistein intake, Lubahn said. He also noted experimental evidence in both cell cultures and animal cancer models shows genistein has cancer protective effects.

Studies Lubahn participated in at the NIH found genistein prevented prostate cancer in mice whose estrogen receptor (ER) alpha gene was inactivated. This type of mice were fed 300 mg/kg/d of genistein compared to mice fed a similar amount of casein. The study suggested genistein exerts its cancer protective effects by interacting with ER-alpha genes. The mice in this study quickly got well-differentiated carcinoma (WDC), but had less incidence of poorly differentiated carcinoma (PDC).

Another study Lubahn and his team conducted found dietary genistein reduced the incidence of cancer in ER wild-type (WT)/transgenic adenocarcinoma of mouse prostate mice, but not in mice whose ER-alpha or  ER-beta genes were inactivated (Endocrinology. 2012 Sep;153(9):4160-70. DOI: 10.1210/en.2012-1030). In this study, genistein only affected the WDC incidence, but had no effect on PDC.

Taking these two studies together, Lubahn concluded that inhibiting ER-alpha and/or stimulating ER-beta will lower PDC incidence in mice.

Studies have shown botanicals of other types can also affect prostate cancer risk. Lubahn said studies have shown plant-based estrogen influences cancer through the hedgehog pathway, which helps regulate stem cells in the body. A 2010 study conducted by Lubahn and his team found seven phytoestrogens, at pharmacological concentrations, inhibited hedgehog signaling in prostate cancer cell lines (Cancer Res. 2010 Apr 15;70(8):3382-90).

Lubahn said the NIH is committed to future research on plant-based estrogen and how it affects prostate and breast cancers.

Learn of more natural ingredients that help reduce prostate cancer on INSIDER's Prostate Cancer Topic Page .