DNA topoisomerase inhibitors: biflavonoids from Ouratea species
Braz. j. med. biol. res
;
35(7): 819-822, July 2002. ilus
Artigo
em Inglês
| LILACS
| ID: lil-316736
RESUMO
Topoisomerase inhibitors are agents with anticancer activity. 7"-O-Methyl-agathisflavone (I) and amentoflavone (II) are biflavonoids and were isolated from the Brazilian plants Ouratea hexasperma and O. semiserrata, respectively. These biflavonoids and the acetyl derivative of II (IIa) are inhibitors of human DNA topoisomerases I at 200 æM, as demonstrated by the relaxation assay of supercoiled DNA, and only agathisflavone (I) at 200 æM also inhibited DNA topoisomerases II-alpha, as observed by decatenation and relaxation assays. The biflavonoids showed concentration-dependent growth inhibitory activities on Ehrlich carcinoma cells in 45-h culture, assayed by a tetrazolium method, with IC50 = 24 ± 1.4 æM for I, 26 ± 1.1 æM for II and 10 ± 0.7 æM for IIa. These biflavonoids were assayed against human K562 leukemia cells in 45-h culture, but only I showed 42 percent growth inhibitory activity at 90 æM. Our results suggest that biflavonoids are targets for DNA topoisomerases and their cytotoxicity is dependent on tumor cell type
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Plantas
/
Flavonoides
/
DNA Topoisomerases Tipo I
/
Inibidores Enzimáticos
/
Antineoplásicos Fitogênicos
Limite:
Animais
/
Humanos
País/Região como assunto:
América do Sul
/
Brasil
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2002
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Estadual Norte Fluminense/BR
/
Universidade Federal Rural do Rio de Janeiro/BR
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