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Theobromine (3,7-dimethylxanthine) was evaluated for genotoxic activity in a series of in vitro assays. Theobromine was not mutagenic in the Ames assay up to a maximum concentration of 5000 micrograms/plate either with or without S9 activation. The compound also failed to induce significant levels of chromosome aberrations in CHO cells (with and without S9 activation) or transformation in Balb/c-3T3 cells. At the maximum tolerated concentration theobromine increased the frequency of TK-/- mutants in mouse lymphoma L5178Y cells. Increased frequencies were observed both with and without S9 activation and they were reproducible in 2 independent experiments. Statistically significant increases in SCEs were obtained in human lymphocytes and in CHO cells under nonactivation test conditions. The spectrum of results in this battery of tests indicate that theobromine treatment results in the expression of genotoxic potential in some assays and the observed activity appears qualitatively and quantitatively similar to that of caffeine, a closely related methylxanthine.
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J Rundell, and
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February 1990,
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association,
D Brusick, and
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S Tarka
July 1989,
Mutation research,
D Brusick, and
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S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
March 2009,
Toxicological research,
D Brusick, and
B Myhr, and
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J Rundell, and
D R Jagannath, and
S Tarka
December 1991,
Mutation research,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
September 1989,
Mutation research,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
January 1991,
Environmental and molecular mutagenesis,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
August 1997,
Mutation research,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
January 1995,
Mutation research,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
January 1989,
Environmental and molecular mutagenesis,
D Brusick, and
B Myhr, and
S Galloway, and
J Rundell, and
D R Jagannath, and
S Tarka
October 1987,
Mutation research,
