We conducted genetic toxicity evaluations of 11 candidate chemopreventive agents with the potential for inhibiting
carcinogenesis in humans at increased risk of
cancer. The compounds were evaluated for bacterial mutagenesis in the Salmonella-E. coli assay, for mammalian mutagenesis in mouse
lymphoma cells, for
chromosome aberrations in Chinese Hamster Ovary (CHO) cells, and for micronucleus induction in mouse bone marrow. Tested agents were
indole 3-carbinol (I3C), bowman-birk inhibitor concentrate (BBIC),
black tea polyphenols (BTP),
farnesol,
geraniol, l-
Se-methylselenocysteine (SeMC), 5,6-dihydro-4H-cyclopenta[1,2]-
dithiol-3-
thione(DC-D3T),
4'-bromoflavone, 2,5,7,8-tetramethyl-(2R-[4R,8R,12-trimethyltridecyl] chroman-6-yloxy)
acetic acid (alpha-
TEA),
SR13668 (2,10-dicarbethoxy-6-methoxy-5,7-dihydro-indolo[2,3-b]
carbazole and
SR16157 (3-O-sulfamoyloxy-7alpha-methyl-21-(2-N,N-diethylaminoethoxy)-19-norpregna-1,3,5(10)-triene). All these agents, except I3C and BTP, were negative in the Salmonella-E. coli assay in the presence and absence of metabolic activation (S9). I3C and BTP induced a weak mutagenic response in the presence and absence of S9 with strains TA100 and TA98, respectively. Of the three compounds tested in the mouse
lymphoma assay (I3C, BBIC, and BTP), only BTP was mutagenic in the presence of S9. In the
chromosomal aberration assay, of the 8 compounds that were tested, 4'-bromoflavone elicited a positive response in the absence of S9 only, while
SR16157 was positive in the presence of S9. The results with
geraniol remain inconclusive. I3C, BBIC and BTP were not tested in the
chromosomal aberration assay. None of the 11 agents induced micronuclei in mouse bone marrow erythrocytes.