Submitted to: Mutation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2001
Publication Date: N/A
Interpretive Summary: Byproducts from the processing of agricultural crops were analyzed for compounds that prevent cancer causing cell damage or inhibit cancer cell growth. We developed methods to separate the components of these byproducts into purified compounds and to assess their anti-cancer activity. A byproduct of ethanol production from corn (corn distiller's solids) was shown to contain components able to prevent the damage to cellular DNA caused by a potent carcinogen. Isoflavones and other compounds separated and identified from a low-value soy processing byproduct (soy molasses) were also shown by these methods to prevent cellular DNA damage caused by potent carcinogens. Further assessment showed that individual isoflavones have different effects; some prevent the DNA damage while others may enhance it. This research initiates studies to identify and assess components in foods that may be important for the prevention of certain types of cancers. Results will benefit consumers, food processors and producers, and health and nutrition researchers.
Technical Abstract: Commercial processing wastes or by-products of crops were found to be sources of antimutagens and human tumor cell growth suppressors. We developed a microplate method to measure genomic DNA damage in Chinese hamster ovary cells with a modified single cell gel electrophoresis (SCGE) assay. This allowed us to measure the repression of 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage by very small amounts of complex mixtures, fractions, or individual chemicals isolated from agricultural byproducts. Of the isoflavones isolated from soybean, daidzein expressed antimutagenic activity, however, genistin and genistein enhanced DNA damage. An antimutagenic response with as little as 50 ng per microplate well of fraction CDS40 isolated from corn distillate solids was observed. We developed a microplate assay to measure the suppression of the growth rate of human cancer cells in which the cytostatic/cytotoxic status at each concentration of the test sample was quantitatively determined. Genistein, genistin, daidzein and daidzin expressed a wide range of growth suppression of HT-29 human colon cancer cells. The biological assays were integrated with, and directed, the separation and analytical chemistry component of this project. Compounds were purified from biologically active fractions and the structure of individual chemicals was determined with analytical HPLC and HPLC-mass spectroscopy.