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Extracts of Euphorbia esula L. and Croton tiglium L., two members of the Euphorbiaceae which have been used widely in folk medicine for treating cancers, showed antileukemic activity against the P-388 lymphocytic leukemia in mice. Systematic fractionation of the extract of Euphorbia esula L. led to characterization of a major antileukemic component as the(More)
Radiolabeled caffeine was administered orally at 5 mg/kg to adult, male volunteers. Blood, saliva, expired CO2, urine, and feces were collected and analyzed for total radiolabeled equivalents, caffeine, and its metabolites. High-performance liquid chromatography (HPLC) was the principal technique used to separate caffeine and the various metabolites with(More)
In an effort to determine the structural requirements for the significant antileukemic, cytotoxic, antitubulin, and antimitotic activity exhibited by the novel ansa macrolide, maytansine (1), four new C-3 ester and six new C-9 ether homologues were synthesized. The biological activities of these compounds were assayed and compared to the activities of(More)
The two major metabolites of ellipticine (NSC 71795) were isolated from rat bile by a combination of solvent extraction, partition column chromatography, and reverse phase high-performance liquid chromatography. Purification and structural elucidation of the bile products were aided by administration of the drug with a dual label (14C and 2H). The two(More)
N-(Phosphonacetyl)-L-aspartic acid (PALA) is an antitumor agent which is currently under clinical study. A gas chromatography--mass spectrometry--selected ion monitoring assay procedure using [13C]PALA as the internal standard has been developed for the quantitation of PALA in biological samples. Standard curves which related ion intensity peak height(More)
Methods are described for quantitating N-(phosphonacetyl)L-aspartic acid (PALA), a new antitumor agent presently undergoing clinical evaluation. These methods were developed to measure this compound in serum by gas chromatography using the selectivity of a nitrogen-phosphorus detector and in serum and urine by the gas chromatographic/mass spectrometric(More)
A major caffeine metabolite (A1) has been isolated from human urine by a combination of solvent extraction, reverse phase high-pressure liquid chromatography, and silica gel open column chromatography. The chromatographic and spectral properties of A1 are identical with an authentic sample of 5-acetylamino-6-amino-3-methyluracil. A stable isotope-labeling(More)