Inhibition of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline-mediated DNA-adduct formation by chlorophyllin in Drosophila.
The effect of chlorophyllin on 2-amino-3,8-dimethyimidazo[4,5-f]quinoxaline (MeIQx)-mediated DNA-adduct formation in Drosophila was studied. Third-instar larvae of Drosophila were fed MeIQx at 1 mg/6.5 g-feed/bottle, with or without chlorophyllin (100-300 mg). After a 6 h feeding exposure to MeIQx, the larvae were divided into 2 groups. The first group was examined for covalent DNA adducts by 32P-postlabeling assay. The second group was assayed for DNA damage by allowing the larvae to develop to adults and measuring the male/female ratio (males, DNA repair-deficient; females, DNA repair-proficient). The 32 P-postlabeling results indicated a significant decrease in DNA adduct levels in larvae treated with MeIQx and 300 mg chlorophyllin (1.7 +/- 0.7 adducts/10(7) nucleotides) as compared with MeIQx-treated larvae 6.5 +/- 2.1 adducts/10(7) nucleotides). The results on male/female sex ratios also indicated a chlorophyllin-induced decrease in DNA damage by exposure to MeIQx. The suppressive effect of chlorophyllin on the genotoxic actions of a polycyclic mutagen, MeIQx, may be a result of complex formation between chlorophyllin and the mutagen.
Sugiyama
C
C
Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Japan.
Shinoda
A
A
Hayatsu
H
H
Negishi
T
T
D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D001345:Autoradiography; D002735:Chlorophyllides / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D018736:DNA Adducts / Q000378:metabolism*; D004249:DNA Damage; D004330:Drosophila; D005260:Female; D008297:Male; D009153:Mutagens / Q000378:metabolism / Q000633:toxicity*; D010761:Phosphorus Radioisotopes; D011810:Quinoxalines / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000633:toxicity*
D016587:Antimutagenic Agents; D002735:Chlorophyllides; D018736:DNA Adducts; D009153:Mutagens; D010761:Phosphorus Radioisotopes; D011810:Quinoxalines; C036990:2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline; D004247:DNA; C007020:chlorophyllin