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Cancer Chemoprevention by Antioxidants in Berries

 
The Cancer Center recently was fortunate to appoint Dr. Gary Stoner to direct the Molecular Carcinogenesis and Chemoprevention Program. As Dr. Stoner’s academic home is the Division of Hematology and Oncology, I have been fortunate to be able to work with him on transferring his NIH R01 Grant to MCW. He graciously agreed to allow us to feature a brief glimpse into his fascinating research with Berry extracts as a means of Cancer Prevention.

Chemoprevention is defined as the administration of one or more chemical entities, either as individual drugs or as dietary supplements, to prevent the initiation of premalignant lesions and their progression to cancer. Prevention of cancer recurrence in patients who have received treatment for cancer is another objective of chemoprevention. For several years, Dr. Stoner’s laboratory has been evaluating the ability of lyophilized (freeze-dried) black raspberries (Rubus occidentalis, BRBs) and components extracted from BRBs to inhibit carcinogen-induced cancer in the rodent esophagus and colon. Inclusion of BRB powder in the rodent diet results in about a 60-80% inhibition of chemically-induced cancer in the esophagus and colon, respectively. Esophageal cancer ranks eighth in order of cancer occurrence in the U.S. and colon cancer ranks third. Some of the known chemopreventive agents in BRBs include vitamins A, C, E and folic acid; calcium and selenium; β-carotene, α-carotene, and lutein; polyphenols such as ellagic acid, ferulic acid, p-coumaric acid, quercetin, and several anthocyanins; and phytosterols such as β-sitosterol, stigmasterol, and kaempferol. For the non-researchers among us, the English translation: anthocyanins are water-soluble pigments that are responsible for the color of berries and other plants, and they are the most prevalent compounds in BRBs. Dr. Stoner’s laboratory has shown that BRBs and their component anthocyanins reduce cell proliferation, inflammation and angiogenesis (new blood vessel formation) and stimulate apoptosis (cell death) and cellular function (differentiation). They work by positively affecting genes associated with all of these cellular functions. Recent clinical trials by Dr. Stoner and his colleagues suggest that BRBs also have a protective effect on the development of cancer in the human esophagus and colon. Currently, he is working with colleagues at MCW to develop additional human trials.

By isolating and concentrating the bioactive compounds the possible benefits of BRBs and other berry types can be measured more precisely. To assure “standardized” berry preparations for studies, each berry type is of the same cultivar, picked at about the same degree of ripeness, washed and frozen within 2–4h of the time of picking, and freeze-dried under conditions that preserve the components in the berries. To obtain the anthocyanins needed for his RO1 studies, Dr. Stoner has been in collaboration with the University of Minnesota where the anthocyanins are isolated from berry powder. Very large quantities of berries are required and it was determined that he would need nearly 200 lbs of black raspberry powder (equivalent to 2,000 lbs of fresh BRBs) to provide the necessary anthocyanins for just Aim 1 of his grant.

As Dr. Stoner is new to MCW, if any researchers/investigators know of qualified Natural Product Chemists or Plant geneticists on campus, Dr. Stoner would be interested in collaborating with them to advance portions of his Research.

Article written by Bradley Condon, Financial Analyst II, Department of Medicine

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Page Updated 11/30/2011