PYRETHROID METABOLISM - MICROSOMAL OXIDASE METABOLITES OF (S)-BIOALLETHRIN AND THE 6 NATURAL PYRETHRINS

Metabolism of the chrysanthemates (S)-bioallethrin, cinerin I, jasmolin I, and pyrethrin I by NADPH-dependent oxidases of mouse liver microsomes yields 13-18 metabolites in each case oxidized at the methyl, methylene, and alkenyl substituents to form alcohols, aldehydes, carboxylic acids, epoxides, and dihydrodiols. Rat microsomes are more specific than mouse microsomes in hydroxylating the (E)-methyl substituent of the 2-methylpropenyl moiety compared with other molecular sites. Metabolites in the urine of allethrin-treated rats include compounds modified in both the 2-methylprope-nyl and allyl moieties as free carboxylic acids and glucuronides. The pyrethrates cinerin II, jasmolin II, and pyrethrin II undergo microsomal hydrolysis of the methoxycarbonyl group and oxidation of the butenyl, pentenyl, and pentadienyl substituents to alcohols, epoxides, and dihydrodiols. Metabolites of these chrysanthemates and pyrethrates are tentatively identified by chemical ionization mass spectrometry following treatment with diazomethane or diazoethane and bis(trimethylsilyl)acet-amide and separation by high-resolution gas chromatography with hydrogen as the carrier gas. © 1990, American Chemical Society. All rights reserved.