biflavonoid from Luxemburgia nobilis as inhibitor of DNA topoisomerases

Abstract The biflavonoid 2′′,3′′-diidroochnaflavone (1), isolated from the leaves of LUXEMBURGIA NOBILIS, was cytotoxic to murine Ehrlich carcinoma (IC 50 = 17.2 μM) and human leukemia K562 cells (IC 50 = 89.0 μM) in a concentration-dependent manner in 45 h cell culture. The acetyl (1A) and methyl (...

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Veröffentlicht in:	Planta medica 2005-06, Vol.71 (6), p.561-563
Hauptverfasser:	Oliveira, M.C, Carvalho, M.G. de, Grynberg, N.F, Brioso, P.S
Format:	Artikel
Sprache:	eng
Schlagworte:	2'',3''-diidroochnaflavone Animals anticarcinogenic activity Antineoplastic Agents, Phytogenic - administration & dosage Antineoplastic Agents, Phytogenic - pharmacology Antineoplastic Agents, Phytogenic - therapeutic use biflavonoids Biflavonoids - administration & dosage Biflavonoids - pharmacology Biflavonoids - therapeutic use Cell Line, Tumor - drug effects cultured cells cytotoxicity DNA topoisomerase Dose-Response Relationship, Drug enzyme inhibitors Enzyme Inhibitors - administration & dosage Enzyme Inhibitors - pharmacology Enzyme Inhibitors - therapeutic use flavonoids Humans Inhibitory Concentration 50 Letter Luxemburgia nobilis Mice Ochnaceae phytochemicals Phytotherapy plant extracts Plant Extracts - administration & dosage Plant Extracts - pharmacology Plant Extracts - therapeutic use Topoisomerase I Inhibitors
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Zusammenfassung:	Abstract The biflavonoid 2′′,3′′-diidroochnaflavone (1), isolated from the leaves of LUXEMBURGIA NOBILIS, was cytotoxic to murine Ehrlich carcinoma (IC 50 = 17.2 μM) and human leukemia K562 cells (IC 50 = 89.0 μM) in a concentration-dependent manner in 45 h cell culture. The acetyl (1A) and methyl (1B) derivatives of 1 were not cytotoxic to these tumour cells at 67.0 and 82.0 μM concentrations, respectively. Biflavonoid 1 as well 1A inhibit the activity of human DNA topoisomerases I and II-α as observed in relaxation and decatenation assays. In addition, we show that 1 is a DNA interacting agent, which causes DNA unwinding in an assay with topoisomerase I. Also, spectrophotometric titration of 1 with DNA resulted in a pronounced hypochromic effect.
ISSN:	0032-0943 1439-0221
DOI:	10.1055/s-2005-864159