BIPHENYL COMPOUNDS ARE HYDROXYL RADICAL SCAVENGERS - THEIR EFFECTIVE INHIBITION FOR UV-INDUCED MUTATION IN SALMONELLA-TYPHIMURIUM TA102

In our previous study, we found several hydroxylated biphenyl compound s have a great scavenging effect for hydroxyl radicals ( .OH). In this study, to elucidate the relationship between generation of the .OH an d photo-mutagenesis, six biphenyl compounds such as dehydrodieugenol, dehydrodivanillyl alcohol, dehydrodidihydroeugenol, dehydrodicreosol, magnolol and honokiol, respectively, were examined for their ability t o inhibit UV-induced mutation in Salmonella typhimurium TA102. The rel ative mutagenic activities (RMA, %) indicated the mutation frequency o f treated cells divided by the mutation frequency of control cells tim es 100%. The RMA (%) are as follows: 28 +/- 1, 31 +/- 1, 33 +/- 1, 41 +/- 2, 62 +/- 1, and 62 +/- 4 at concentrations of 5 mu g per plate fo r dehydrodieugenol, dehydrodivanillyl alcohol, dehydrodidihydroeugenol , dehydrodicreosol, magnolol, and honokiol, respectively. These values indicate that low concentrations of these biphenyl compounds effectiv ely suppress UV-induced mutagenesis. Also, these compounds acted as ef fective antimutagens in a dose-dependent manner (0.00005-5 mu g per pl ate). These compounds are effective .OH scavengers. Consequently, the results obtained above suggest that these compounds could inhibit agai nst UV-induced mutations by scavenging of .OH generated by UV irradiat ion. The results also suggest that .OH are associated with UV-induced mutation in Salmonella typhimurium TA102.