Studies in detoxication. 67. The biosynthesis of the glucuronides of umbelliferone and 4-methylumbelliferone and their use in fluorimetric determination of β-glucuronidase

Abstract

Umbelliferone (7-hydroxycoumarin) and its con- jugates appear to be metabolites of coumarin in the rabbit (Mead, Smith & Williams, 1955). It was observed that, although umbelliferone fluoresced strongly in ultraviolet light at pH 9-10, its conjugates showed little or no fluorescence. The glucu- ronide and ethereal sulphate of umbelliferone were therefore made and the former was found to be practically non-fluorescent. The possibility that these conjugates could be used as substrates for the determination of ,-glucuronidase and arylsul- phatase was therefore investigated. Since umbelliferone is highly fluorescent it appeared likely that these conjugates could be used for the deternina- tion of the enzymes in very small amounts of material. The present communication deals with the use of the glucuronides of umbelliferone and the cheaper 4-methylumbelliferone (7-hydroxy-4-