THE USE OF SINGLE-CELL GEL-ELECTROPHORESIS AND FLOW-CYTOMETRY TO IDENTIFY ANTIMUTAGENS FROM COMMERCIAL SOYBEAN BY-PRODUCTS

Single cell gel electrophoresis (alkaline Comet assay) and flow cytome tric methods were combined into an assay that enables the analysis of direct DNA damage and longer-term whole cell clastogenicity in mammali an cells. We employed these techniques to analyze the antimutagenic ac tivity of by-products of commercial soybean processing. At a concentra tion of 1 mg/ml, the soybean molasses by-product was found to repress 66% of the mutagenic capacity of the direct-acting mutagen 2-acetoxyac etylaminofluorene (2AAAF) in Chinese hamster lung (CHL) cells. At a co ncentration of 50 mu g/ml, fraction PCC (an ethanol extract of soybean molasses) repressed 70% of the genotoxic potency of 500 nM 2AAAF as m easured by the Comet assay. Fraction PCC was also effective in protect ing CHL cells from 2AAAF-induced clastogenic damage. Using a forward m utation assay in Chinese hamster ovary cells (line AS52), PCC protecte d the cells against 2AAAF-induced cytotoxicity and point mutation at a specific gene target. These data indicate that agronomic crops such a s soybean may yield a wealth of commercially available antimutagenic a gents that may be suitable as chemoprotective food supplements. (C) 19 98 Elsevier Science B.V. All rights reserved.