Benzo[a]pyrene (3,4-Benzopyrene)

Benzo[a]pyrene (3,4-Benzopyrene) (BaP, B[a]P) is a polycyclic aromatic hydrocarbon formed by a benzene ring fused to pyrene^[1]. The diol epoxide metabolites of Benzo[a]pyrene (3,4-Benzopyrene), BPDE, react with and bind to DNA, resulting in mutations and carcinogenesis^[2]. Benzo[a]pyrene (3,4-Benzopyrene) has toxicity on the nervous system, immune system, reproductive system, and carcinogenicity^[3].

In vitro Benzo[a]pyrene (3,4-Benzopyrene) (0.2µg/ml; 24h) induces the transformation of human mammary epithelial cells^[4]. Benzo[a]pyrene (3,4-Benzopyrene) (1,5, 10μM; up to 6 days) also confers enhanced susceptibility to bacterial infection^[5]. The carcinogenesis caused by Benzo[a]pyrene (3,4-Benzopyrene) (0.05-500μg/ml; 24h) can be restored by isoflavone biochanin A^[6].

In vivo Benzo[a]pyrene (3,4-Benzopyrene) (300μg/kg; 3 days; oral gavage) results in diminished mRNA expression of the NMDA NR2B receptor subunit to resulting in late-life deficits in cortical neuronal activity in the offspring^[7]. Benzo[a]pyrene (3,4-Benzopyrene) (150µg/kg; once per day for 30 days; oral gavage) also increases 7-ethoxyresorufin-O-deethylase activity in liver microsomal fraction^[8].

References:
[1] Bukowska, Bożena et al. “Benzo[*a*]pyrene-Environmental Occurrence, Human Exposure, and Mechanisms of Toxicity.” *International journal of molecular sciences* vol. 23,11 6348. 6 Jun. 2022, doi:10.3390/ijms23116348
[2] Matter, Brock et al. “Formation of diastereomeric benzo[a]pyrene diol epoxide-guanine adducts in p53 gene-derived DNA sequences.” *Chemical research in toxicology* vol. 17,6 (2004): 731-41. doi:10.1021/tx049974l
[3] Fu, Chenghao et al. “Benzo(a)pyrene and cardiovascular diseases: An overview of pre-clinical studies focused on the underlying molecular mechanism.” *Frontiers in nutrition* vol. 9 978475. 4 Aug. 2022, doi:10.3389/fnut.2022.978475
[4] Stampfer, M R, and J C Bartley. “Induction of transformation and continuous cell lines from normal human mammary epithelial cells after exposure to benzo[a]pyrene.” *Proceedings of the National Academy of Sciences of the United States of America*vol. 82,8 (1985): 2394-8. doi:10.1073/pnas.82.8.2394
[5] Clark, Ryan S et al. “Validation of research trajectory 1 of an Exposome framework: Exposure to benzo(a)pyrene confers enhanced susceptibility to bacterial infection.” *Environmental research* vol. 146 (2016): 173-84. doi:10.1016/j.envres.2015.12.027
[6] Cassady, J M et al. “Use of a mammalian cell culture benzo(a)pyrene metabolism assay for the detection of potential anticarcinogens from natural products: inhibition of metabolism by biochanin A, an isoflavone from Trifolium pratense L.” *Cancer research* vol. 48,22 (1988): 6257-61.
[7] McCallister, Monique M et al. “Prenatal exposure to benzo(a)pyrene impairs later-life cortical neuronal function.” *Neurotoxicology* vol. 29,5 (2008): 846-54. doi:10.1016/j.neuro.2008.07.008
[8]Kang, Hwan Goo et al. “Changes of biomarkers with oral exposure to benzo(a)pyrene, phenanthrene and pyrene in rats.” *Journal of veterinary science*vol. 8,4 (2007): 361-8. doi:10.4142/jvs.2007.8.4.361