title: Metabolism of the mesoionic compound (MI-D) by mouse liver microsome, detection of its metabolite in vivo, and acute toxicity in mice.
abstract: The mesoionic derivative 4-phenyl-5-[4-nitrocinnamoyl]-1,3,4-thiadiazolyl-2-phenylamine chloride (MI-D) has antitumoral and anti-inflammatory effects. In this study, we present aspects of its metabolism and toxicity in mice. MI-D was metabolized in vitro by liver microsome, generating a main product with a much shorter retention time than MI-D in high-performance liquid chromatography (HPLC) analysis but with a spectrum similar to that of the original molecule. Mass spectrometry with electrospray ionization in positive mode analysis of the purified compound by HPLC indicated that the product of metabolism has four additional hydroxyl groups (m/z = 465) compared with MI-D (m/z = 401). The HPLC analyses of plasma and urine samples from mice treated with MI-D showed the presence of the metabolite product. The kinetic parameters K(m) (19.5 +/- 4.5 microM) and V(max) [1.5 +/- 0.4 units of fluorescence/(100 microg of microsomal protein/mL/s)] were estimated, confirming the metabolism of MI-D and indicating that the reaction follows Michaelis-Menten kinetics. Acute toxicity was established on the basis of an estimation of mean lethal dose (LD-50; 181.2 mg/kg) and histopathological analysis of animals that survived the LD-50 test. Abdominal adhesions, inflammatory foci, and formation of granulomas were observed. Altogether, the results contribute to the advancement of research in support of MI-D as a future chemotherapeutic drug.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Setor de Ciências Biológicas, Universidade Federal do Paraná, CP 19046 CEP 81531-990 Curitiba, Paraná, Brazil.
authors.forename: Silvia
authors.initials: S
authors.lastname: Romão
authors.forename: Silvia M S C
authors.initials: SM
authors.lastname: Cadena
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Amorim
authors.forename: Stelia C
authors.initials: SC
authors.lastname: Méndez-Sánchez
authors.forename: Aurea
authors.initials: A
authors.lastname: Echevarria
authors.forename: Edson F
authors.initials: EF
authors.lastname: Silva
authors.forename: Maria Eliane M
authors.initials: ME
authors.lastname: Rocha
authors.forename: Guilhermina R
authors.initials: GR
authors.lastname: Noleto
authors.forename: Eva G S
authors.initials: EG
authors.lastname: Carnieri
authors.forename: Glaucia R
authors.initials: GR
authors.lastname: Martinez
authors.forename: Maria Benigna M
authors.initials: MB
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002934:Cinnamates / Q000378:metabolism* / Q000633:toxicity; D007928:Lethal Dose 50; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism*; D013830:Thiadiazoles / Q000378:metabolism* / Q000633:toxicity
chemical_list: C116348:4-phenyl-5-(4-nitrocinnamoyl)-1,3,4-thiadiazolium-2-phenylamine; D002934:Cinnamates; D013830:Thiadiazoles