Applicability of the OECD 455 in-vitro assay for determination of hERa agonistic activity of isoflavonoids.
Toxicol Appl Pharmacol
; 386: 114831, 2020 01 01.
Article
en En
| MEDLINE
| ID: mdl-31756431
ABSTRACT
The Organisation for Economic Co-operation and Development (OECD)-validated transactivation assay using the human estrogen receptor alpha (hERα) Hela9903 cell line is used for activity evaluation of hERα agonists and antagonists. Due to many advantages, this assay is broadly used as an initial screening process. However, response significantly higher from that of 17-ß estradiol (E2) was observed with phytoestrogens for concentrations commonly above 1 µM in previous studies. The main aim of this study was thus to ascertain the applicability of OECD protocol 455 for evaluation of estrogenic activity of natural flavonoids, including known phytoestrogens. The estrogenic activities of aglycones as well as of O-methylated and glycosylated flavonoids were evaluated. Supra-maximal luciferase activity was seen for most of the flavonoids tested at concentrations even below 1 µM. hERα-mediated luciferase expression was confirmed with the competition assay specified in OECD protocol 455. However, at concentrations above 1 µM, non-specific interactions were also observed. Instead of EC50 values, which could not be determined for most of the isoflavonoids tested, the concentrations corresponding to 10% (PC10) and 50% (PC50) of the maximum activity of the positive control, E2, were used for quantitative determination of estrogenic activities. Appropriate evaluation of the data obtained with the current OECD protocol 455 validated assay represents a valuable tool for initial screening of natural flavonoids for estrogenic activity.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Flavonoides
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Pruebas de Toxicidad
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Receptor alfa de Estrógeno
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Fitoestrógenos
Límite:
Humans
Idioma:
En
Revista:
Toxicol Appl Pharmacol
Año:
2020
Tipo del documento:
Article
País de afiliación:
Eslovenia