DNA topoisomerase inhibitors: biflavonoids from Ouratea species
Braz. j. med. biol. res
;
35(7): 819-822, July 2002. ilus
Article
in English
| 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
Full text:
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Index:
LILACS (Americas)
Main subject:
Plants
/
Flavonoids
/
DNA Topoisomerases, Type I
/
Enzyme Inhibitors
/
Antineoplastic Agents, Phytogenic
Limits:
Animals
/
Humans
Country/Region as subject:
South America
/
Brazil
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2002
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Universidade Estadual Norte Fluminense/BR
/
Universidade Federal Rural do Rio de Janeiro/BR
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