DNA topoisomerase inhibitors: biflavonoids from Ouratea species
Braz. j. med. biol. res
; 35(7): 819-822, July 2002. ilus
Article
em En
| LILACS
| ID: lil-316736
Biblioteca responsável:
BR1.1
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:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Plantas
/
Flavonoides
/
DNA Topoisomerases Tipo I
/
Inibidores Enzimáticos
/
Antineoplásicos Fitogênicos
Limite:
Animals
/
Humans
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Braz. j. med. biol. res
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil