18-9 |
Prospecting for cancer chemopreventive agents in foods |
K. L. PARKIN1, M. Wettasinghe1, B. W. Bolling1, H. Xiao1, D. M. Peterson2, L. C. Plhak1, and L. Liu1. (1) Dept. of Food Science, Univ. of Wisconsin, Madison, 1605 Linden Dr., A-119 Babcock Hall, Madison, WI 53706-1519, (2) Dept. of Agronomy, Univ. of Wisconsin, Madison, 501 Walnut St., 116 Barley & Malt Lab., Madison, WI 53726-2334 The development of a murine hepatoma (Hepa 1c1c7) cell line some 15 years ago for the isolation of phase II enzyme inducing agents by a group from Johns Hopkins University led to the identification of sulforaphane as a major cancer chemopreventive agent in broccoli. This general bioassay for phase II enzyme induction can employ different cell lines, and is advocated by NIH for use as an effective screening tool for cancer chemopreventive agents. We have found that choices among alternative methodological protocols using this bioassay can have profound impact on the ability to detect and isolate phase II enzyme inducing agents from botanical sources. These considerations include the nature of raw material preparation, the specific solvent used to extract the prospective bioactive agent(s), and the inclusion of even minor amounts of nonaqueous solvent as carrier of the agent or extract into the bioassay. The impact of these choices and considerations on the discovery and documentation of the phase II inducing effect of extracts or known compounds will be illustrated using examples from the authors’ laboratories involving the study of common fruits, vegetables and grains. This bioassay has been successfully used to isolate fractions enriched in potential cancer chemopreventive agents in table beets, green beans, green onion, soybeans, oats, and cranberry fruit. In some cases, the active agent has been purified and identified.
Session 18, Chemistry and analysis of phytochemicals or plant bioactive materials
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