Mutagens formed from beta-carbolines with aromatic amines.

Area of Science:

• Environmental Science
• Toxicology
• Genetics

Background:

• Norharman, found in cigarette smoke and cooked foods, is not mutagenic alone.
• It becomes mutagenic to Salmonella strains in the presence of aromatic amines like aniline.
• This co-mutagenic property necessitates understanding its genotoxic effects in humans due to co-exposure.

Purpose of the Study:

• To elucidate the co-mutagenic mechanisms of norharman with aromatic amines.
• To investigate the genotoxicity and carcinogenicity of resulting aminophenyl-beta-carboline derivatives.
• To assess the potential endogenous formation and human health risks.

Main Methods:

• Investigated the interaction of norharman with aniline to form 9-(4 ahydroxyamino)-9H-pyrido[3,4-b]indole (APNH).
• Assessed mutagenic and clastogenic actions of APNH and related compounds in bacterial and mammalian cells.
• Administered APNH to F344 rats to evaluate in vivo toxicity and carcinogenicity, including liver preneoplastic lesions.

Main Results:

• Norharman and aniline interaction produces APNH, which forms DNA adducts (dG-C8-APNH), inducing mutations.
• Aminophenyl-beta-carboline derivatives, particularly APNH, exhibited potent mutagenic and clastogenic activities.
• APNH induced severe testicular toxicity and liver preneoplastic lesions in rats; it was detected in rat urine.

Conclusions:

• Aminophenyl-beta-carboline derivatives are formed from environmental exposure to norharman and aromatic amines.
• These derivatives possess significant mutagenic and carcinogenic potential.
• They represent a novel class of potential endogenous mutagens and carcinogens relevant to human health.