In vitro and in vivo mutagenicity studies on taurohyodeoxycolic acid.

The mutagenicity of a new biliary acid, taurohyodeoxycholic acid (THDCA, Io, Praxis, CAS 2958-04-5), was assayed by using 5 different tests. The Ames test (reverse mutation assay on Salmonella typhimurium) and the DNA damage and repair test (in Saccharomyces cerevisiae) allowed to study the genetic THDCA-induced mutations in prokaryotes and eukaryotes (doses of 100, 200 and 400 micrograms/plate or 100, 200 and 400 micrograms/ml, respectively). In vivo and in vitro chromosomal aberrations were studied by using micronucleus test in mice (doses of 100, 220 and 500 mg/kg in oral study and 50, 100 and 200 mg/kg in subcutaneous study) and human lymphocytes cytogenetic test (doses of 50, 100, 220 and 500 micrograms/ml of THDCA). At last the host-mediated assay was performed on THDCA-treated mice (following oral or subcutaneous administration) in order to test the potential mutagenic activity of its metabolites on a S. typhimurium strain. The results obtained in these studies showed that THDCA did not induce any signs of promutagenic, mutagenic or clastogenic direct or metabolite-mediated activity.