Metabolic activation of emodin in the reconstituted cytochrome P-450 system of the hepatic microsomes of rats.
Studies were undertaken to elucidate further the mechanism by which emodin, an anthraquinoid mycotoxin and constituent of rhubarb, was converted into a direct-acting mutagen to Salmonella typhimurium TA1537 by the hepatic microsomes and the reconstituted cytochrome P-450 system. Emodin was activated into a mutagenic principle(s) in the reconstituted cytochrome P-450 system, and its mutagenicity was significantly higher with the fraction II (P-448 type) than the fraction I (P-450 type) derived from the hepatic microsomes of PCB-induced rats. Thin-layer chromatographic analysis revealed that the purified cytochrome II-a (maximal CO-differential spectrum at 448.0 nm and high-spin form) activity converted emodin into 2-hydroxy-emodin, a direct-acting mutagen.
D000818:Animals; D000880:Anthraquinones / Q000378:metabolism*; D001711:Biotransformation / Q000187:drug effects; D002474:Cell-Free System; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004642:Emodin / Q000378:metabolism* / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D009153:Mutagens / Q000378:metabolism* / Q000494:pharmacology; D011078:Polychlorinated Biphenyls / Q000494:pharmacology; D051381:Rats; D012486:Salmonella typhimurium / Q000187:drug effects
D000880:Anthraquinones; D009153:Mutagens; D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D004642:Emodin