Inhibitory effect of lichen constituents on mutagenicity induced by heterocyclic amines.
Physodic acid, one of the main constituents of Hypogymnia enteromorpha, inhibited the mutagenicity of indirect mutagens, including benzo[a]pyrene and heterocyclic amines in Salmonella typhimurium TA 98. In contrast, it was not effective against direct mutagens such as 6-nitropiperonal and adriamycin. Its antimutagenicity was not associated with free-radical scavenging or antioxidative activities. Physodic acid seemed to inhibit the formation of reactive metabolites, such as N-hydroxy-Trp-P-2, by blocking the hepatic microsomal oxidation systems. Another component of H. enteromorpha, physodalic acid, also inhibited mutagenicity of a heterocyclic amine, Trp-P-2, in S. typhimurium TA 98, even though it was reportedly mutagenic in S. typhimurium TA 100.
Osawa
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Department of Environmental Toxicology, University of California, Davis, CA 95616.
Kumon
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H
Reece
C A
CA
Shibamoto
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T
D000818:Animals; D001711:Biotransformation; D002243:Carbolines / Q000494:pharmacology; D003990:Dibenzoxepins / Q000494:pharmacology*; D006571:Heterocyclic Compounds / Q000494:pharmacology*; D008011:Lichens; D008862:Microsomes, Liver / Q000378:metabolism; D009152:Mutagenicity Tests; D009153:Mutagens / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects; D014020:Tissue Extracts / Q000494:pharmacology*
D002243:Carbolines; D003990:Dibenzoxepins; D006571:Heterocyclic Compounds; D009153:Mutagens; D014020:Tissue Extracts; C019133:3-amino-1-methyl-5H-pyrido(4,3-b)indole; C043056:physodic acid