Mixture Of Metabolites Research Articles

High-performance liquid chromatographic method for simultaneous determination of [1-methyl- 14C]caffeine and its eight major metabolites in rat urine

A selective and sensitive reversed-phase liquid chromatographic method was developed for the simultaneous analysis of [1-Me- 14C]caffeine and its eight major radiolabelled metabolites in rat urine. The separation of the complex mixture of caffeine metabolites was achieved by gradient elution with a dual solvent system using an endcapped C 18 reversed-phase column, which in contrast to commonly used C 18 reversed-phase columns also allows the separation of the two isomers of 6-amino-5-( N-formylmethylamino)-1,3-dimethyluracil (1,3,7-DAU), a caffeine metabolite of quantitative importance predominantly occurring in rat. As caffeine is metabolised primarily by members of the cytochrome P450 1A (CYP1A) subfamiliy, determination of the pattern of caffeine metabolites in rat urine enables analysis of activities of this important enzyme subfamily in vivo. Since CYP1A is suggested to be involved in the detoxification of bilirubin, the assay may be applied to search for untoxic inducers of CYP1A which might be of pharmacological interest in the treatment of hyperbilirubinaemia.

Determination of 1,4-benzodiazepines and their metabolites by capillary electrophoresis and high-performance liquid chromatography using ultraviolet and electrospray ionisation mass spectrometry

A study is presented for the separation and determination of fifteen 1,4-benzodiazepine drugs and metabolites by capillary electrophoresis (CE) compared with high-performance liquid chromatography (HPLC). A comparison is made between the CE determination of the compounds by conventional UV detection and LC determination with electrospray ionisation (ESI) ion-trap mass spectrometry. CE is shown to provide superior separation to HPLC but the MS–MS capability of the ion-trap allows for the specific detection and determination of four of the compounds, diazepam, N′-desmethyldiazepam, oxazepam and temazepam in the hair of a patient under clinical treatment with diazepam and temazepam. Selected mixtures of drugs and metabolites are determined by CE and LC and the determination of diazepam and its metabolites by CE–UV–ESI-MS–MS is also presented.

Biodiversity and potentials of marine-derived microorganisms

The marine environment is a prolific resource for the isolation of less exploited microorganisms. As a matter of fact, in the sea, untapped habitats exist with unique characteristics. In addition, the potential contribution of marine sources to the discovery of new bioactive molecules was recently recognized. Biosearch Italia possesses a collection of about 40 000 microorganisms, isolated from different ecological niches. In the search of new bioactive entities, investigations were expanded to marine habitats including marine sediments and organisms. More then 800 microorganisms have been isolated. About half belong to fungal genera, the others being actinomycetes. The frequency of antibiotic activities produced by these marine strains has been determined. Initial data are encouraging: marine isolates produce antibiotic activities with frequencies comparable to terrestrial ones. These activities probably represent a mixture of novel metabolites and known products previously discovered from terrestrial isolates. Further investigations are ongoing to assess the novelty of these observed microbiological activities.

Microsomal metabolism of dictamnine: identification of metabolites and evaluation of their mutagenicity in Salmonella typhimurium.

Incubation of the furoquinoline alkaloid dictamnine with microsomal fractions from phenobarbital-induced rat liver resulted in a metabolite mixture from which demethyl-dictamnine and dictamnic acid were identified by a GCMS technique. The identity of the two compounds was confirmed by synthesis. Other metabolites were characterized by their mass spectra only. The pattern of the metabolites suggested a possible pathway of metabolism in vitro. We assume that the metabolism of dictamnine is analogous to the metabolism of the related 8-methoxypsoralen and takes place via an unstable epoxide and subsequent oxidative opening of the furan ring. Direct evidence for the formation of an epoxide was, however, not obtained. The identified compounds as well as some putative metabolites were shown to be non-mutagenic in Salmonella typhimurium TA98 except for 8-hydroxydictamnine, which, however, was not detected in the metabolite mixture.

Advances in separation science relating to clinical nutrition.

Advances in separation science are leading to more sensitive and more specific analysis of the complex mixtures of metabolites, vitamins and nutrients found in biofluids. Recent developments include capillary electrokinetic separations such as capillary electrophoresis, and the linking of separation methods to new forms of mass spectrometry.

Trilinear PARAFAC decomposition of synchronous fluorescence spectra of mixtures of the major metabolites of acetylsalicylic acid.

Mixtures of the three major metabolites of acetylsalicylic acid (salicylic, gentisic and salicyluric acid) were analyzed by synchronous molecular fluorescence spectroscopy. Three-way data matrices were generated by acquisition of spectra as a function of the pH (between 2 and 11) and of different relative concentrations of the three components. The PARAFAC trilinear model, without restrictions and using one factor per metabolite, was used in the data analysis. A full decomposition of the data matrices into the spectra, concentration and pH profiles was obtained. This result shows that molecular fluorescence spectroscopy can be used for the development of robust analytical methods for the simultaneous determination of the three major metabolites of acetylsalicylic acid in complex background samples.

Residues and metabolism of 19-nortestosterone laurate in steers.

The illegal use of 19-nortestosterone (19NT; 4-estren-17 beta-ol-3-one; nandrolone) and its esters in livestock, for growth promotion purposes, has been widely reported in the European Union. The target residues for surveillance of abuse in bovine urine and bile samples are 17 alpha- and 17 beta-19NT, although this choice of target residues is not based on in vivo radiotracer biotransformation data. In this study, four steers were administered [3H2]- and [2H3] 17 beta-19NT laurate (2 mg kg-1 body mass) by intramuscular injection and blood, urine, faeces and bile samples were taken for 30 d until slaughter, after which tissues were sampled for total residue analysis. Total plasma radiolabelled residues reached a maximum of 56.3 +/- 15.9 pmol ml-1 at 36 h and were still appreciable (13.3 +/- 1.6 pmol ml-1) 30 d after treatment. Throughout the study period, total residue concentrations in bile (about 2-16 nmol ml-1), urine and faeces (0.5-3 nmol ml-1 or g-1) were higher than in other tissues sampled at slaughter. At slaughter there was evidence of residue accumulation in pigmented eye tissue (33.1 +/- 6.1 pmol g-1) and in white (13.4 +/- 3.4 pmol g-1) and black hair (28.9 +/- 8.9 pmol g-1). Evaluation of radio-HPLC profiles of urine and bile extracts generally indicated that 19NT and 19NT laurate residues were present in relatively small amounts among a complex mixture of metabolites. GC-MS analysis of glucuronidase-hydrolysed bile extracts indicated that the major metabolites were 5 beta-estrane-3 alpha, 17 alpha-diol, 5 alpha-estrane-3 beta, 17 alpha-diol. 5 alpha-estran-3 alpha-ol-17-one (norandrosterone) and estra-1,3,5(10)-triene-3,17 alpha-diol (17 alpha-estradiol).

Gender- and age-specific cytotoxic susceptibility to benzene metabolites in vitro.

Benzene, a widely used compound, is a known carcinogen and hematopoietic toxicant. Several studies have shown gender and age differences in the responses to benzene-induced hematotoxicity. It is not known if these differences in response are due to age- or gender-associated metabolic differences or to age- or gender-associated differences in the susceptibilities of the target cells. In order to address this issue, mouse colony-forming units-erythroid (CFU-e, an erythroid precursor cell particularly susceptible to benzene toxicity) were cultured in the presence of either individual benzene metabolites or binary mixtures of these metabolites. CFU-e were obtained from unexposed age-matched adult male and female (both virgin and pregnant) Swiss Webster (SW) mice and from SW male and female 16-day fetuses. The metabolites used were phenol, hydroquinone, catechol, benzoquinone, and trans, trans-muconic acid. The concentrations of the individual metabolites used were 10, 20, and 40 microM. Binary mixtures of metabolites were prepared using the lowest concentrations of the individual metabolites that caused cytotoxicity. These concentrations were 10 microM for hydroquinone, catechol, and benzoquinone, and 40 microM for phenol and muconic acid. In general, the CFU-e from adult females (both virgin and pregnant) were more resistant to the toxic effects of the individual metabolites than CFU-e from other subjects. CFU-e from adult males were more susceptible to the cytotoxic effects of hydroquinone and benzoquinone than CFU-e from other subjects and CFU-e from both male and female fetuses were highly sensitive to the toxic effects of catechol. On the other hand, CFU-e from adult males were less susceptible to the cytotoxic effects of catechol than CFU-e from other subjects. Similar results were observed with binary mixtures of metabolites. CFU-e from adult males were more susceptible to the binary mixtures than CFU-e from virgin females and CFU-e from fetal males were more susceptible than CFU-e from fetal females. In addition, CFU-e from fetuses were more 'resistant than CFU-e from adults to the cytotoxic effects of those binary mixtures that did not contain catechol. In contrast, binary mixtures containing catechol were more toxic to fetal cells than to adult cells. These results suggest that differences in benzene hematotoxicity associated with gender and age may be due, at least in part, to intrinsic factors at the level of the target cell rather than solely to age- or gender-related differences in the metabolism of benzene.

Plant secondary metabolite diversity as a resistance trait against insects: a test with Sitophilus granarius (Coleoptera: Curculionidae) and seed secondary metabolites

A hypothesis is tested about the functioning of plant secondary metabolite diversity taking into account the role of concentration of mixtures or single compounds: a high diversity secondary metabolite mixture in high concentration provides a more effective protection against herbivores than single compounds or low diversity mixtures in both low and high concentrations. Additionally the role of two unusual secondary metabolites for a weevil when they are incorporated in its diet is explored. Number of eggs laid and diet consumption are measured in the granary weevil Sitophilus granarius exposed to cereal and non-cereal secondary metabolites incorporated in artificial diets to test the hypothesis. Artificial diets had one, two, four or six compounds. The mixtures or single compounds were offered simultaneously to the weevils in concentrations ranging from 0.05 to 5mg g−1 in a multiple choice experiment. Low oviposition in high concentration six compounds mixture supported the hypothesis. However, low oviposition in a low concentration mixture of four compounds suggests that a moderate diversity may be equally functional in low and high concentrations. Diet consumption by the weevil was not affected by concentration but an increasing number of compounds in the diet reduced it slightly but significantly. The unusual secondary metabolites for the weevil were less or equally effective reducing oviposition and consumption as usual compounds did.

Identification of Novel Metabolites of Prostaglandin E2Formed by Isolated Rat Hepatocytes

The metabolism of prostaglandin E2(PGE2) in isolated rat hepatocytes led to the formation of four major as well as several minor products which were structurally characterized using electrospray tandem mass spectrometry. The major metabolites identified included dinor-PGE1, dinor-PGE2, and tetranor-PGE1and the taurine conjugates of dinor-PGE1and dinor-PGE2. Several minor metabolites including the taurine conjugates of PGE2and tetranor PGE1along with a glucuronide conjugate of PGE2were also identified. These taurine conjugates had not been previously identified in studies of PGE2metabolism, yet comprised nearly 50% of the mixture of metabolites after 40-min incubations. Experiments carried out with deuterium-labeled PGE2([3,3,4,4-D4]PGE2) resulted in the complete loss of all deuterium atoms in dinor-PGE1, dinor-PGE2, and tetranor metabolites during incubation with hepatocytes. Metabolism via classic β-oxidation pathways would predict one deuterium atom retained by dinor-PGE1and two deuterium atoms retained by dinor-PGE2. When PGE2was incubated with isolated rat hepatocytes in buffer containing 30% D2O, substantial incorporation (30%) of one deuterium atom could be observed in the dinor metabolites along with 10% incorporation into the tetranor and residual PGE2. Deuterium-labeled PGE1([3,3,4,4-D4]PGE1) was metabolized to D2-dinor-PGE1, tetranor-PGE1, and the taurine conjugate of D2-dinor-PGE1by isolated rat hepatocytes. The loss of deuterium during metabolism of the deuterated substrates of PGE2, but not PGE1, as well as the incorporation of deuterium atoms from the aqueous solvent into PGE2metabolites suggested that the Δ5double bond and sequential isomerization reactions lead to eventual exchange of the protons from carbon atom 4 of PGE2with water.

ANALYSIS OF ANAEROBIC MICROORGANISMS METABOLITES

ABSTRACT This paper presents an overwiew of anaerobic bacterias metabolites and their effects on Microbially Improved oil recovery (MIOR). Chemical analysis methods for coexisting gas-, water-, and oil phases of MIOR field tests or laboratory experiments are described for mixtures of potential metabolites of anaerobic microorganisms. The obtained data are compared with literature values. The metabolites in the gas- and oil phases are determined qualitatively and quantitatively in the water phases. GC, HPLC, GC/MS measurements for metabolites and additionly biopolymer, biosurfactant, and sugar determinations were described. The accuracy of the several analysis methods and their application limits are critically discussed

Measurement of Benzo[A]Pyrene as a Surrogate for Total Human Exposure to PAH

ABSTRACT This is a brief overview of our use of benzo[a]pyrene (B[a]P) as a surrogate of human exposure starting with exploration of this “multi-media” pollutant in the THEES study and continuing with explorations of the monitoring of this substance as a metabolite in human urine. In the THEES pilot study the predominant pathway of exposure was usually the ingestion pathway. The analysis of urinary metabolites using the Becher/Bjørseth “reverse metabolism” technique provided very low yields (ca 5 % recovery) for B[a]P metabolites although it works well for lower molecular weight metabolites. Current interest focuses on the recovery of conjugates (Phase 2 metabolites) since deconjugation in workup involves loss of information. A study of rat urine and feces indicated that the metabolite mixture varied with installation pathway- i.e. gastric versus intratracheal installation of B[a]P. We are exploring new methods for the isolation and separation of individual conjugates such as the hydroxy-PAH sulfates.

Cytotoxicity, Accumulation, and Efflux of Cisplatin and Its Metabolites in Human Ovarian Carcinoma Cells

Cisplatin (CP) is one of the most useful antineoplastic drugs. When CP is dissolved in human plasma, different metabolites are formed. Using the OV 2008 human ovarian cancer cell line, we examined the relative cytotoxicities of CP and its metabolites (aquated CP [AP], monomethionine CP [MP], bismethionine CP [BP], and a mixture of CP metabolites in ultrafiltrated human plasma [UP])in vitro.By clonogenic assay, cell survival (percent of mean ± SE) of OV 2008 cells exposed for 1 hr to 6.7 μMof CP was 9.8 ± 0.7 and for its equal platinum contents of AP, MP, BP, and UP solutions were 3.3 ± 0.7, 9.8 ± 0.9, 15.9 ± 1.1, 76.8 ± 2.1, and 13.1 ± 0.7, respectively. AP was the most cytotoxic species, and BP was the least cytotoxic species. Cellular platinum uptake (ng/106cells) after addition of 0.33, 1.6, and 2.5 mMof each species for 1 hr was measured and a strong correlation was found between cytotoxicity of each CP metabolite and its corresponding cellular platinum (Pt) uptake (r= 0.997). There was a strong correlation between cytotoxicity of the CP metabolites and their DNA binding. With fractionation of these cells into DNA, nucleoplasm and cytoplasm, the highest platinum content was found on DNA. The most important factor that seems to be responsible for the cytotoxicities of the different CP metabolites is the amount of their associated intracellular accumulation, and particularly the degree of their binding to DNA.

Chemical defenses of the tropical green seaweed Neomeris annulata Dickie: effects of multiple compounds on feeding by herbivores

The calcareous green alga Neomeris annulata Dickie is widely distributed in shallow inshore waters of many reef habitats in the Caribbean and Pacific. We examined the effects of three brominated sesquiterpenes found in Neomeris annulata on Guam against three reef herbivores that are not strongly deterred by CaCO 3 in their diets: the parrotfishes Scarus sordidus Forsskål, S. schlegeli (Bleeker) and the sea urchin Diadema savignyi Michelin. The effects of each metabolite were examined separately to compare their effectiveness toward the different herbivores. The major brominated sesquiterpene (compound 1; ca. 1% dry mass in thallus tips) deterred feeding by all three herbivores at or below natural concentrations, as did the other two minor compounds. The terpene most effective at deterring feeding by all three herbivores was a closely related minor compound (compound 2: ca. 0.5% dry mass in thallus tips). We then tested for possible interactions among the three metabolites and synergistic effects by seeing whether natural combinations of the three metabolites enhanced their effectiveness as chemical defenses. The natural mixture of metabolites was never more effective than either compound 1 or compound 2 alone, suggesting no enhanced or synergistic effect of multiple metabolites. In fact, at higher concentrations approaching natural concentrations found in the thallus tips, compound 2 was more effective at deterring feeding by S. schlegeli by itself than in the naturally occurring mixture of terpenes.

Urinary Excretion Kinetics of Pyrene and Benzo(a)pyrene Metabolites Following Intravenous Administration of the Parent Compounds or the Metabolites

The detailed urinary excretion profiles of 1-hydroxypyrene (1-OHP) and benzo(a)pyrene (BaP) metabolites were studied following acute intravenous administration of pyrene and BaP, respectively, or after injection of the metabolites themselves. Male Sprague–Dawley rats were exposed to 4 μmol 1-OHP/kg or 15 μmol pyrene/kg. Other rats were exposed to 2 μmol/kg of a mixture of four BaP metabolites (3-hydroxyBaP (3-OHBaP), 9-hydroxyBaP (9-OHBaP), trans-4,5-dihydrodiolBaP (4,5-diolBaP), and trans-9,10-dihydrodiol (9,10-diolBaP)) or 40 μmol BaP/kg. Urine samples were collected at frequent intervals over 48 or 96 hr. Injection of both pyrene and 1-OHP produced similar biphasic excretion profiles. An apparent first order half life of 6.9 and 6.6 hr, respectively, could be calculated for the second phase of elimination. Comparable 3-OHBaP excretion profiles were obtained after injection of BaP or a mixture of BaP metabolites. Elimination kinetics showed at least two steps, the second step having a first order apparent half life of 8.1 and 7.6 hr following BaP and BaP metabolites injection, respectively. Time profiles of 4,5-diolBaP excretion following administration of BaP or a mixture of BaP metabolites were almost identical. Elimination was linear and a first order apparent half life of 3.1 and 3.6 hr could be calculated. Elimination of 4,5-diolBaP was much more rapid than that of 3-OHBaP and complete within 24 hr postdosing. Therefore, results suggest that (1) phase I biotransformation is not the rate-limiting step in the excretion of 1-OHP, and 3-OHBaP and 4,5-diolBaP following injection of pyrene and BaP, respectively, and (2) similarities in the first order apparent half life of 3-OHBaP and 1-OHP for the late phase of excretion suggest that 1-OHP could be a good surrogate for 3-OHBaP.

Application of capillary electrophoresis and related techniques to drug metabolism studies

The use of capillary electrophrosis (CE) for the separation of small organic molecules such as pharmaceutical agents and drug/xenobiotic metabolites has become increasingly popular. This has arisen, at least in part, from the complimentary mode of separation afforded by CE when compared to the more mature technique of HPLC. Other qualities of CE include relative ease of method of development, rapid analysis, and low solvent consumption. The recent introduction of a variety of detector systems (including UV diode array, laser-induced fluorescence, conductivity) and the demonstrated coupling of CE to MS have also aided acceptance of this technology. In the present report, we review the role of CE coupled to various detector systems including a mass spectrometer for the characterization of both in vitro and in vivo derived drug metabolite mixtures. Attributes of CE for this application are demonstrated by discussion of metabolism studies of the neuroleptic agent haloperidol. Various aspects of the development and use of CE and CE-MS for the characterization of haloperidol metabolites, including criteria for selection of parameters such as pH, ionic strength, extent of organic modification, and the use of nonaqueous capillary zone electrophoresis are discussed. We also consider potential limitations of CE and CE-MS for drug metabolism research and describe the introduction of membrane preconcentration-CE (mPC-CE) and mPC-CE-MS as a solution that overcomes the rather poor concentration limits of detection of CE methods without compromising the resolution of analytes or separation efficiency of this technique.

Sesquiterpenoids from a Cell Suspension Culture of the LiverwortPorella vernicosa Lindb

The liverwort Porella vernicosa Lindb. was cultured in vitro in Murashige and Skoog's medium. The pungent sesquiterpene dialdehyde, polygodial, was found as the major metabolite (20.3%). The second major metabolite was norpinguisone methyl ester (18.7%). In addition β-bisabolene (12.7%), drimenol (8.4%), cyclocolorenone (7.5%) and other drimane and pinguisane sesquiterpenoids were identified by GC-MS analysis. In the field-grown liverwort, the major metabolite was norpinguisone (24.5%) accompanied by polygodial (21.7%) and cyclocolorenone (13.4%). Thus the content of polygodial in the mixture of metabolites produced by P. vernicosa cultured in vitro was similar to that in the field-grown plant.

Detection and quantitation of phosphorus metabolites in crude tissue extracts by 1H and 31P NMR: use of gradient assisted 1H‐31P HMQC experiments, with selective pulses, for the assignment of less abundant metabolites

The analysis of crude tissue extracts by NMR has proven to be of use in the study of metabolism due to the non-destructive and non-selective character of the technique. Lists of 1H and 31P NMR assignments of phosphorus metabolites in water solution at specified pH and ionic composition are of large general value but their usefulness may be limited when analysing complex mixtures of metabolites at low concentrations. In this work we report on the use of gradient-assisted proton detected multiple quantum 1H and 31P coherence experiments with selective pulses for the rapid and unambiguous assignments of some crowded regions in 1H and 31P spectra of crude extracts from rat liver. The amplitudes of the gradient episodes were calibrated to optimize the coherence transfer pathway between proton and phosphorus, and the delay for the evolution of the long-range coupling was calculated from values of 3JPH and 4JPH ranging from 1.4 to 7.5 Hz. Moreover, a selective 90 degrees Gaussian pulse on the 31P channel was introduced to increase the resolution in the F1-domain and make the method even faster. The procedure was then applied to unambiguously assign the ID 31P and 1H spectra of perchloric acid extracts of rat livers that had been stimulated with phenylephrine, dBcAMP and glucagon and thus detect changes in the concentration of less abundant metabolites such as phosphoenolpyruvate, UDP-glucose and AMP. The fact that the quantification of these metabolites by either 31P and 1H methods lead to different results is discussed, and the use of 1H NMR spectroscopy for the quantification of phosphorus metabolites whose signal are too weak or poorly resolved in a 31P spectrum is proposed.

Human bone marrow toxicity of a non-nucleoside pyrrolo[2,3- d]pyrimidine : M. R. Nassiri, R. S. Taichman, T. E. Renan, S. G. Emerson, L. B. Townsend, and J. C. Drach. University of Michigan, Ann Arbor, Michigan, 48109-1078, USA

Benzene, a widely used compound, is a known carcinogen and hematopoietic toxicant. Several studies have shown gender and age differences in the responses to benzene-induced hematotoxicity. It is not known if these differences in response are due to age- or gender-associated metabolic differences or to age- or gender-associated differences in the susceptibilities of the target cells. In order to address this issue, mouse colony-forming units-erythroid (CFU-e, an erythroid precursor cell particularly susceptible to benzene toxicity) were cultured in the presence of either individual benzene metabolites or binary mixtures of these metabolites. CFU-e were obtained from unexposed age-matched adult male and female (both virgin and pregnant) Swiss Webster (SW) mice and from SW male and female 16-day fetuses. The metabolites used were phenol, hydroquinone, catechol, benzoquinone, andtrans,trans-muconic acid. The concentrations of the individual metabolites used were 10, 20, and 40 μM. Binary mixtures of metabolites were prepared using the lowest concentrations of the individual metabolites that caused cytotoxicity. These concentrations were 10 μM for hydroquinone, catechol, and benzoquinone, and 40 μM for phenol and muconic acid. In general, the CFU-e from adult females (both virgin and pregnant) were more resistant to the toxic effects of the individual metabolites than CFU-e from other subjects. CFU-e from adult males were more susceptible to the cytotoxic effects of hydroquinone and benzoquinone than CFU-e from other subjects and CFU-e from both male and female fetuses were highly sensitive to the toxic effects of catechol. On the other hand, CFU-e from adult males were less susceptible to the cytotoxic effects of catechol than CFU-e from other subjects. Similar results were observed with binary mixtures of metabolites. CFU-e from adult males were more susceptible to the binary mixtures than CFU-e from virgin females and CFU-e from fetal males were more susceptible than CFU-e from fetal females. In addition, CFU-e from fetuses were more resistant than CFU-e from adults to the cytotoxic effects of those binary mixtures that did not contain catechol. In contrast, binary mixtures containing catechol were more toxic to fetal cells than to adult cells. These results suggest that differences in benzene hematotoxicity associated with gender and age may be due, at least in part, to intrinsic factors at the level of the target cell rather than solely to age- or gender-related differences in the metabolism of benzene.

Identification of Microbial and Rat Metabolites of Triflusulfuron Methyl, A New Sugar Beet Herbicide

Triflusulfuron methyl (methyl 2-[[[[[4-(dimethylamino)-6-(2,2,2-trifluoroethoxy)-1,3,5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]-3-methylbenzoate) is a new selective low use rate sulfonylurea herbicide for the control of many broad-leaved weeds and grasses in sugar beets. Our studies show the compound undergoes rapid microbial metabolism using Streptomyces griseolus and that a mixture of similar metabolites is excreted by triflusulfuron methyl-dosed rats. Nine intact sulfonylurea metabolites were tentatively identified in microbial studies, and five of these were later identified in urine or feces of rats dosed with radiolabeled triflusulfuron methyl. Metabolic reactions include alkyl and/or aryl oxidation, N-dealkylation, and ester hydrolysis. All identifications were made using liquid chromatography/mass spectrometry (LC/MS) with fast atom bombardment (FAB) ionization. FAB mass spectra gave strong protonated molecular ions and structurally useful fragment ions of these extremely thermally labile metabolites