Umbelliferone (7-hydroxycoumarin) and its conjugates 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 glucuronide 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 arylsulphatase was therefore investigated. Since umbelliferone is highly fluorescent it appeared likely that these conjugates could be used for the deternination 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-4methylcoumarin) for the determination of f,glucuronidase. (This work has been briefly reported by Mead, Smith & Williams, 1954.) The ethereal sulphates of -umbelliferone and 4-methylumbelliferone show a fluorescence which is considerably less than the corresponding hydroxycoumarins. We have attempted to use these compounds for the fluorimetric assay of arylsulphatase, but we do not consider them satisfactory because their fluorescence is sufficient to give relatively high blank values. The ,B-glucosides of umbelliferone and 4methylumbelliferone, however, have been found to be satisfactory for the determination of ,-glucosidase, and an account of these compounds will be given later. EXPERIMENTAL Materials. Umbelliferone, m.p. 224-226°, purchased from British Drug Houses Ltd., had a pale-reddish colour, and paper chromatography showed that it was not pure.In n-butanol-acetic acid-water (4:1:5 by vol.), besides a main fluorescent spot due to umbelliferone, three other much weaker fluorescent spots were present. As a standard for fluorescent purposes umbelliferone was purified by way of the sulphuric ester. The umbelliferone (4.5 g.) was * Part 66: Jondorf, Parke & Williams (1955).dissolved in pyridine (10 ml.) and a solution of chlorosulphonic acid (3 g.) in pyridine (10 ml.) added carefully with cooling. The mixture was then kept at room temp. for 24 hr. Water (100 ml.) was then added, followed by a slight excess of KHCO3. The precipitate which formed was collected by filtration, dissolved in the minimum of hot water (charcoal) and the solution filtered. On cooling the potassium umbeUiferone sulphate (potassium 2-oxo-1:2benzopyran-7-yl sulphate) separated and was recrystallized from 80 % (v/v) aqueous ethanol as colourless needles

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The lifespan of mice bearing ascitic leukemia L1210 could be prolonged by treatment with (-)-emetine dihydrochloride. Optimal dosage schedules required emetine administration daily for 5 days (QD, day 1–5) or intermittently on every 4th day. (Q4D, day 1, 5, 9). Compounds related to (-)-emetine which are active in other biological systems, having the correct stereospecific structure at the C-1′ position in the molecule, a secondary amine structure at N-2′ and an ethyl-group substituent at C-3 were also effective in prolonging the survival time of L1210 leukemic mice. The effective compounds were (-)-cephaeline, (±)-2,3-dehydroemetine, (-)-2,3-dehydroemetine, (-)-tubulosine and (-)-O-methyltubulosine. In contrast, (-)-isoemetine and several derivatives of (±)-2,3-dehydroemetine, lacking the critical configuration at C-1′ or substitution at the N-2′ and C-3 positions in the molecule, were inactive in the mouse leukemia system, when administered according to the Q4D, day 1, 5, 9 schedule.