ANTIMUTAGENICITY OF POLYPHENOL-RICH FRACTIONS FROM SORGHUM-BICOLOR GRAIN

Polyphenols extracted from a bird-resistant sorghum (Sorghum bicolor (L) Moench) grain cultivar SSK30 were separated into three crude fractions: non-tannin polyphenols with small M(r) (F1); proanthocyanidins with M(r) values between 2000 and 10000 (F2); and proanthocyanidins with much larger M(r) values of around 10000 50000 (F3). Each fraction was tested for mutagenicity using mutants of Salmonella typhimurium (the Ames test) or the somatic mutation and recombination test (SMART) employing Drosophila melanogaster. None of the fractions was positive with either test. On the other hand the crude polyphenols all acted as antimutagens when coincubated with mutants of S typhimurium and standard mutagens (sodium azide, daunomycin and 2-aminofluorene). The order of antimutagenicity was F3 > F2 > F1, a decrease with decreasing M(r). It is possible that a different mechanism of polyphenol antimutagenicity occurs against the mutagen sodium azide when compared with the mutagens daunomycin and 2-aminofluorene.