4,8-DiMeIQx is an orally active mutagen, selective dopaminergic neurotoxicant, and DNA damaging agent. 4,8-DiMeIQx can be isolated from cooked beef, sausage, pork, and chicken. 4,8-DiMeIQx induces reverse mutations in *Salmonella typhimurium* TA98 in the presence or absence of S9 mix, and forms DNA adducts in vivo in rat liver. 4,8-DiMeIQx exhibits selective neurotoxicity toward dopaminergic neurons. 4,8-DiMeIQx shows no activity against non-dopaminergic neurons. 4,8-DiMeIQx can be used in studies related to Parkinson's disease and colorectal cancer [1] [2] [3] [4].
In Vivo, 4,8-DiMeIQx (50 mg/kg; p.o.; single dose) forms DNA adducts in rat liver in vivo, with N2-(2'-deoxyguanosin-8-yl)-4,8-DiMeIQx as the major adduct representing ~60% of total adducts and having a relative adduct level of 3.54×10-5 at 72 hours post-single 50 mg/kg oral dose[3]. 4,8-DiMeIQx (0.5 mg per rat; p.o.; single dose) oral administration to male AGUS rats results in predominant urinary excretion of radioactivity within 24 hours, with BNF-induced intestinal enzyme activity increasing fecal excretion; major metabolites include hydroxylated and acetylated forms, with varying mutagenic potency relative to the parent compound[4].
In Vitro, 4,8-DiMeIQx (1 μg per assay) is mutagenic to Salmonella typhimurium TA98 with S9 mix, inducing 206,000 revertants per μg, and accounts for 9% of the total mutagenicity of bacteriological-grade beef extract[1]. 4,8-DiMeIQx (100 nM-5 μM; 24 h) is selectively neurotoxic to dopaminergic neurons in E17 rat primary midbrain cultures, with a threshold dose of 100 nM and significant dopaminergic neuron loss observed across all tested concentrations from 100 nM to 5 μM, while non-dopaminergic neurons remain unaffected[2]. 4,8-DiMeIQx (100 nM-5 μM; 24 h) does not elicit significant neurite length changes in either dopaminergic or non-dopaminergic neurons in E17 rat primary midbrain cultures at concentrations from 100 nM to 5 μM after 24 h of incubation[2].
References:
[1]. Takahashi M, et al. Identification and quantification of 2-amino-3,4,8-trimethylimidazo- [4,5-f]quinoxaline (4,8-DiMeIQx) in beef extract. Carcinogenesis. 1985 Oct;6(10):1537-9.
[2]. Cruz-Hernandez A, et al. Selective dopaminergic neurotoxicity of three heterocyclic amine subclasses in primary rat midbrain neurons. Neurotoxicology. 2018 Mar;65:68-84.
[3]. Frandsen H, et al. Formation of DNA adducts by the food mutagen 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx) in vitro and in vivo. Identification of a N2-(2'-deoxyguanosin-8-yl)-4,8-DiMeIQx adduct. Carcinogenesis. 1994 Nov;15(11):2553-8.
[4]. Knize MG, et al. The metabolism of 4,8-DiMeIQx in conventional and germ-free rats. Carcinogenesis. 1989 Aug;10(8):1479-84.
In Vivo, 4,8-DiMeIQx (50 mg/kg; p.o.; single dose) forms DNA adducts in rat liver in vivo, with N2-(2'-deoxyguanosin-8-yl)-4,8-DiMeIQx as the major adduct representing ~60% of total adducts and having a relative adduct level of 3.54×10-5 at 72 hours post-single 50 mg/kg oral dose[3]. 4,8-DiMeIQx (0.5 mg per rat; p.o.; single dose) oral administration to male AGUS rats results in predominant urinary excretion of radioactivity within 24 hours, with BNF-induced intestinal enzyme activity increasing fecal excretion; major metabolites include hydroxylated and acetylated forms, with varying mutagenic potency relative to the parent compound[4].
In Vitro, 4,8-DiMeIQx (1 μg per assay) is mutagenic to Salmonella typhimurium TA98 with S9 mix, inducing 206,000 revertants per μg, and accounts for 9% of the total mutagenicity of bacteriological-grade beef extract[1]. 4,8-DiMeIQx (100 nM-5 μM; 24 h) is selectively neurotoxic to dopaminergic neurons in E17 rat primary midbrain cultures, with a threshold dose of 100 nM and significant dopaminergic neuron loss observed across all tested concentrations from 100 nM to 5 μM, while non-dopaminergic neurons remain unaffected[2]. 4,8-DiMeIQx (100 nM-5 μM; 24 h) does not elicit significant neurite length changes in either dopaminergic or non-dopaminergic neurons in E17 rat primary midbrain cultures at concentrations from 100 nM to 5 μM after 24 h of incubation[2].
References:
[1]. Takahashi M, et al. Identification and quantification of 2-amino-3,4,8-trimethylimidazo- [4,5-f]quinoxaline (4,8-DiMeIQx) in beef extract. Carcinogenesis. 1985 Oct;6(10):1537-9.
[2]. Cruz-Hernandez A, et al. Selective dopaminergic neurotoxicity of three heterocyclic amine subclasses in primary rat midbrain neurons. Neurotoxicology. 2018 Mar;65:68-84.
[3]. Frandsen H, et al. Formation of DNA adducts by the food mutagen 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx) in vitro and in vivo. Identification of a N2-(2'-deoxyguanosin-8-yl)-4,8-DiMeIQx adduct. Carcinogenesis. 1994 Nov;15(11):2553-8.
[4]. Knize MG, et al. The metabolism of 4,8-DiMeIQx in conventional and germ-free rats. Carcinogenesis. 1989 Aug;10(8):1479-84.