The mutagenic activity of sodium perborate

Sodium perborate (CAS No. 1333-73-9, 10486-00-7, or 13517-20-9, depending on the structural formula given) is produced in huge amounts mainly for its use as a bleaching agent in laundry detergents. Its action involves the liberation of active oxygen species at elevated temperatures. In view of the widespread use of this compound it is surprising to note that no mutagenicity test data yet exist. The investigations reported in this paper have shown that sodium perborate is indeed capable of producing mutagenic changes in a number of in vitro test systems. Its potential for inflicting damage to DNA could be demonstrated in an assay which is tailored to probe for oxidative damage induced by a chemical agent. As expected, sodium perborate proved to be able to oxidize thymidine to an appreciable extent at an incubation temperature of 80 degrees C, but even at 40 degrees C thymidine oxidation was measurable. The compound induced point mutations in the Salmonella typhimurium strains TA100 and TA102, while TA98 did not respond. Also, incubation in the presence of a mammalian auxiliary metabolic system (rat liver S9) abolished the mutagenic activity completely. Finally, Chinese hamster ovary cells (strain CHO-K1) were shown to undergo extensive chromosomal damage when treated with sodium perborate. The rather unusual prevalence of chromosome rearrangements was especially noted. Sodium perborate is thus to be regarded as a direct-acting in vitro mutagen.