DNA adduct formation from quaternary benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine as revealed by the 32P-postlabeling technique.
Using the 32P-postlabeling assay, we investigated the ability of quaternary benzo[c]phenanthridine alkaloids, sanguinarine, chelerythrine and fagaronine, to form DNA adducts in vitro. Two enhanced versions of the assay (enrichment by nuclease P1 and 1-butanol extraction) were utilized in the study. Hepatic microsomes of rats pre-treated with beta-naphthoflavone or those of uninduced rats, used as metabolic activators, were incubated in the presence of calf thymus DNA and the alkaloids, with NADPH used as a cofactor. Under these conditions sanguinarine and chelerythrine, but not fagaronine, formed DNA adducts detectable by 32P-postlabeling. DNA adduct formation by both alkaloids was found to be concentration dependent. When analyzing different atomic and bond indices of the C11-C12 bond (ring B) in alkaloid molecules we found that fagaronine behaved differently from sanguinarine and chelerythrine. While sanguinarine and chelerythrine showed a preference for electrophilic attack indicating higher potential to be activated by cytochrome P450, fagaronine exhibited a tendency for nucleophilic attack. Our results demonstrate that sanguinarine and chelerythrine are metabolized by hepatic microsomes to species, which generate DNA adducts.
Stiborová
Marie
M
Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 2 Prague, Czech Republic. stiborov@natur.cuni.cz
Simánek
Vilím
V
Frei
Eva
E
Hobza
Pavel
P
Ulrichová
Jitka
J
D000470:Alkaloids / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism* / Q000494:pharmacology; D053119:Benzophenanthridines; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D018736:DNA Adducts / Q000096:biosynthesis*; D007364:Intercalating Agents / Q000378:metabolism* / Q000494:pharmacology; D007546:Isoquinolines; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D010617:Phenanthridines / Q000378:metabolism* / Q000494:pharmacology; D010761:Phosphorus Radioisotopes / Q000032:analysis; D011789:Quantum Theory; D051381:Rats; D017207:Rats, Sprague-Dawley
D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D053119:Benzophenanthridines; D018736:DNA Adducts; D007364:Intercalating Agents; D007546:Isoquinolines; D010617:Phenanthridines; D010761:Phosphorus Radioisotopes; C002066:fagaronine; D003577:Cytochrome P-450 Enzyme System; C005705:sanguinarine; C016299:chelerythrine