McCalla D R, Kaiser C, Lu C, Messier F, Quilliam M A
Mutat Res. 1981 Jul;82(2):201-11. doi: 10.1016/0027-5107(81)90150-0.
Addition of 1 mg amaranth (FD&C Red No. 2) to the top agar of Salmonella/S9 assay plates decreased the yield of revertants induced by 20 micrograms 2-acetylaminofluorene (AAF) by over 50% and additional amaranth completely eliminated the mutagenic response. Similar suppression of AAF mutagenicity was seen with sulfonazo III, another azo dye. The suppressive effect of amaranth was greatest at low S9 concentrations and decreased as the amount of S9 was increased. When N-hydroxyacetylaminofluorene (N-OH-AAF) was used as mutagen, amaranth had little or no effect on either the number of revertants obtained or the S9 optimum. Similarly, 1-naphthylamine-4-sulfonic acid (a reduction product of amaranth) did not significantly affect the mutagenicity of AAF. The rate of metabolism of [14C]AAF by the S9 preparations was shown to be markedly decreased by amaranth, as were the levels of both the phenolic metabolites and of N-OH-AAF. Thus, it appeared that amaranth acts by blocking the conversion of AAF to N-OH-AAF and that this effect is caused by the amaranth itself and not by its constituent amines. Further experiments indicated that amaranth greatly decreased the levels of NADPH formed in reaction mixtures comparable to S0 mix in top agar and that such reaction mixtures also metabolized amaranth to colourless compounds. It appears likely that in top agar, NADPH reacts with amaranth at a fast enough rate to limit severely the level of the reduced co-factor (which must be formed from NADPH+ by the action of endogenous glucose-6-phosphate dehydrogenase) and thus decreases the rate of activation of mutagens by other NADPH-dependent processes.
在沙门氏菌/ S9试验平板的顶层琼脂中添加1毫克苋菜红（FD＆C红2号），可使由20微克2-乙酰氨基芴（AAF）诱导的回复突变体产量降低50％以上，额外添加苋菜红则完全消除了诱变反应。另一种偶氮染料磺胺偶氮III对AAF致突变性也有类似的抑制作用。苋菜红的抑制作用在低S9浓度时最大，并随着S9量的增加而降低。当使用N-羟基乙酰氨基芴（N-OH-AAF）作为诱变剂时，苋菜红对获得的回复突变体数量或S9最佳值几乎没有影响。同样，1-萘胺-4-磺酸（苋菜红的还原产物）对AAF的致突变性也没有显著影响。苋菜红显著降低了S9制剂对[14C] AAF的代谢速率，酚类代谢产物和N-OH-AAF的水平也降低了。因此，苋菜红似乎是通过阻断AAF向N-OH-AAF的转化而起作用，并且这种作用是由苋菜红本身引起的，而不是由其组成胺引起的。进一步的实验表明，苋菜红大大降低了在顶层琼脂中与S0混合物相当的反应混合物中形成的NADPH水平，并且这种反应混合物还将苋菜红代谢为无色化合物。在顶层琼脂中，NADPH与苋菜红的反应速率可能足够快，以严重限制还原型辅酶因子的水平（其必须由内源性葡萄糖-6-磷酸脱氢酶的作用从NADPH +形成），从而降低其他NADPH依赖性过程对诱变剂的激活速率。
