In vivo genotoxicity and DNA adduct levels in the liver of rats treated with safrole

Abstract

The induction of chromosome aberrations, sister chromatid exchanges (SCEs), and the formation of DNA adducts was studied in hepatocytes of F344 rats exposed in vivo to safrole. Hepatocytes were isolated 24 h after a single dose of safrole or five repeated doses (once a day) by gastric intubation and allowed to proliferate in Williams' medium E supplemented with epidermal growth factor. Cells were fixed after 48 h in culture. Safrole-DNA adducts were detected by a nuclease P1-enhanced 32P-post-labeling assay in isolated hepatocytes from the rats. While a single dose was not sufficient to induce detectable levels of chromosome aberrations at the time of assay, five repeated doses induced these changes with a maximum frequency of 13.4%, compared with the control value of 1.8%. Both a single dose and five repeated doses induced significant SCEs, to a maximum frequency of 0.81 SCEs per chromosome, while the control value was 0.59 SCEs per chromosome. Two major and two minor DNA adducts were detected after treatment with either a single dose or five repeated doses. The maximum amount of total DNA adducts was 89.8 DNA adducts/10(7) nucleotides. These results show that safrole is a genotoxic carcinogen in the rat liver in vivo and suggest that the cytogenetic effects of this compound may result from covalent DNA modification in the rat liver. This in vivo cytogenetic assay should provide a useful means of evaluation of the genotoxicity of hepatocarcinogens.

Assessment of Toxicity of Myristicin and 1’-Hydroxymyristicin in HepG2 Cell Line

“…While estragole, methyleugenol, safroleand anethole haveproved to be hepatotoxic, genotoxic and 312 carcinogenic, the genotoxic and possibly carcinogenic potential of myristicin at equivalent doses is 313 not to be expected .Dose-dependent formation of protein and DNA adducts in liver [22][23][24][25][26][27][28][29] was 314 observed with allyl alkoxy benzenes. Although DNA adducts in the liver of CD1 female mice were 315 isolated, the binding of myristicin to mouse-liver DNA was weaker than those of other compounds 316 such as safrole, estragole, and methyleugenol 10 .…”

Reduction of Safrole and Methyleugenol in Asari radix et rhizoma by Decoction

“…However, some toxicological studies on animals have revealed that safrole is a weak hepatocarcinogen, genotoxic, and a transplacental carcinogen [6][7][8]. In addition, methyleugenol has been demonstrated to be carcinogenic and genotoxic [9][10][11].…”

Joint FAO/WHO Expert Committee on Food Additives (JECFA)

“…The unstable sulfate ester is anticipated to hydrolyse to form a reactive electrophilic intermediate (carbonium ion or quinonium cation), which binds to proteins and DNA. The formation of protein and DNA adducts in liver is dose dependent (Drinkwater et al, 1976;Swanson et al, 1981;Miller et al, 1982Miller et al, , 1983Boberg et al, 1983;Gardner et al, 1995Gardner et al, , 1996Daimon et al, 1998). Sulfate inhibition studies and in vivo-in vitro unscheduled DNA synthesis (UDS) assays of myristicin, elemicin, estragole, methyl eugenol and the 1 -hydroxy metabolites of estragole and methyl eugenol (Boberg et al, 1983;Caldwell et al, 1992;Hasheminejad & Caldwell, 1994) provide additional evidence that the sulfate ester of the 1 -hydroxy metabolite is the principal intoxication metabolite in animals.…”

“…Dose-dependent formation of safrole-DNA adducts has been studied in rats (Daimon et al, 1998). Male Fischer rats were given either single oral doses of 0, 1, 10, 100, 250 or 500 mg safrole/kg bw or five successive daily doses of 62.5, 125 or 250 mg safrole/kg bw.…”