Effect of butylated hydroxyanisole on in vitro and in vivo nitrosation of dibutylamine

Toxicity to Chinese hamster ovary (CHO) cells of the products of reaction of butylated hydroxyanisole with nitrite at low pH

Butylated hydroxyanisole (BHA) was found to react readily with nitrite in acidified physiological saline. With low concentrations of reactants at pH 2, HPLC analysis demonstrated the formation of two products, tert-butylquinone (BQ) and a second, unidentified compound. Neutralized BHA/nitrite reaction mixtures were highly toxic to cultured Chinese hamster ovary (CHO) cells. At non-lethal concentrations, causing some cell cycle delay, there was a statistically significant but variable induction of endoreduplication and tetraploidy and a very weak induction of chromosome breakage. The effects were similar to those of pure BQ. It is suggested that the formation of toxic products from BHA, by an oxidative reaction such as that described with nitrite, might be involved in the mechanism of BHA carcinogenesis in the rat forestomach.

Butylated hydroxyanisole in perspective

Butylated hydroxyanisole (BHA) is a synthetic food antioxidant used to prevent oils, fats and shortenings from oxidative deterioration and rancidity. This review depicts the current knowledge on BHA. The physical and chemical characteristics of BHA are summarized and its function as a food antioxidant is made clear. The toxicological characteristics of BHA and its metabolic fate in man and animal are briefly reviewed. Special emphasis is laid on the carcinogenicity of BHA in the forestomach of rodents and to related events in the forestomach and other tissues in experimental animals. At present there is sufficient evidence for carcinogenicity of BHA, but there is hardly any indication that BHA is genotoxic. Therefore risk assessment for this epigenetic carcinogen is based on non-stochastic principles. However, the mechanism underlying the tumorigenicity of BHA is not known. In the last part of this review an attempt is made to unravel the unknown mechanism of carcinogenicity. It is hypothesized that BHA gives rise to tumor formation in rodent forestomach by inducing heritable changes in DNA. Evidence is being provided that reactive oxygen species, in particular hydroxylradicals, may play a crucial role. The key question with respect to risk assessment for BHA is whether or not the underlying mechanism is thresholded, which is important for the choice of the appropriate model to assess the risk, if any, for man and to manage any potential risk.