Benzopyrene

Structurally speaking, the colorless isomers of benzopyrene are pentacyclic hydrocarbons and are fusion products of pyrene and a phenylene group.

[2] Benzopyrenes are harmful because they form carcinogenic and mutagenic metabolites (such as (+)-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide from benzo[a]pyrene) which intercalate into DNA, interfering with transcription.

The mechanism of action of benzo[a]pyrene-related DNA modification has been investigated extensively and relates to the activity of cytochrome P450 subclass 1A1 (CYP1A1).

[3] Seemingly, the high activity of CYP1A1 in the intestinal mucosa prevents major amounts of ingested benzo[a]pyrene from entering portal blood and systemic circulation.

[6] In February 2014, NASA announced a greatly upgraded database for tracking polycyclic aromatic hydrocarbons (PAHs), including benzopyrene, in the universe.