Table 1.

Selected chemical mutagens and their mechanisms of action

Mutagen	Kind of mutagen	Mechanism of action	Reference
N-acetyl-2-aminofluorene (AAF)	Indirect acting	- Reacts with guanines at the C8 position in DNA to form a structure that interferes with DNA replication	Gill and Romano (2005)
Acridine (AC)	Direct acting	- At low concentrations binds DNA tightly but reversibly by intercalation - At high concentrations induces DNA strand breaks	Ferguson and Denny (2007)
9-aminoacridine (9-AA)	Direct acting	- Induces frameshift mutations at hot spots where a single base, especially guanine, is repeated - Binds to DNA noncovalently by intercalation	Ferguson and Denny (2007) Hoffmann et al. (2003)
2-aminoanthracene (2-AA)	Indirect acting	- Its electrophilic reactive metabolites form DNA adducts	So et al. (2008) Sugamori et al. (2006)
2-aminofluorene (2-AF)	Indirect acting	- Is converted to reactive carcinogenic ester 2-acetylaminofluorene-N-sulfate, which can attack guanine residues in nucleic acids	DeBaun et al. (1970)
Aflatoxin B1 (AFB1)		- Stimulates the release of free radicals, which cause chromosomal aberrations	Alpsoy et al. (2009)
Benzo(α)pyrene (BP)	Indirect acting	- An active mutagen is benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) - Major adducts of BP-DNA are BPDE-deoxyguanosine (dG) and 9-OH-BP-dG-derived adducts	Smith and Gupta (1996)
Cyclophosphamide (CP)	Indirect acting	- Affects DNA through its alkylating properties and free radical production	Zhang et al. (2005)
Doxorubicin (DXN)	Direct acting	- Induces G:C–T:A transversions - Undergoes electron reduction and leads to the generation of free radical species	Koch et al. (1994) Singal et al. (2000)
Ethyl methanesulfonate (EMS)	Direct acting	- An alkylating agent - At low concentrations alters a base in DNA - Induces DNA strand breaks and lesions as a consequence of depurination	Guha and Khuda-Bukhsh (2003) Achary and Panda (2010)
Methyl methanesulfonate (MMS)	Direct acting	- An alkylating agent - Modifies guanine and adenine to cause base mispairing and replication blocks, respectively	Beranek (1990)
N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)	Direct acting	- Leads to the alkylation of purines and pyrimidines - One of the most important products of MNNG is O6-methylguanine	Koch et al. (1994) Kumaresan et al. (1995) Gulluce et al. (2010)
4-nitro-o-phenylenediamine (NPDA)	Direct acting	- Induces frameshift mutations	Koch et al. (1994)
1-nitropyrene (1-NP)	Direct acting	- Forms DNA adduct N-(deoxyguanosine-8-yl)-1-aminopyrene	Bacolod and Basu (2001)
4-nitroquinoline-N-oxide (NQNO)	Direct acting	- A base substitution agent, principally acting at G residues, inducing mainly GC to AT transitions	Fronza et al. (1992)
Sodium azide (NaN3)	Direct acting	- Mutagenicity is mediated through the production of an organic metabolite (L-azidoadenine) that enters the nucleus and then interacts with DNA and originates point mutations in the genome - Induces G:C→A:T transitions	Koch et al. (1994) Al-Qurainy and Khan (2009) Gulluce et al. (2010)