RESUMO
CONTEXT: Eythrina excelsa Baker (Fabaceae) is a medicinal plant used to treat various ailments including those of the female genital tract. OBJECTIVE: The objective of this study is to investigate the estrogenic and cytotoxic effects of the ethanol extract of the stem bark of E. excelsa. MATERIALS AND METHODS: Erythrina excelsa was evaluated in vitro using the yeast estrogen screen (YES). The extract was then tested in a 3-day uterotrophic assay on ovariectomised Wistar rats at doses of 50 and 100 mg/kg BW/d. Cytotoxic effects were assessed on breast (MCF-7) and colon (HT-29) cancer cell lines using the MTT cell viability assay. Additionally, a LC-PDA-ESI (+)-HRMS and HRMS/MS method was developed and applied for the identification of representative secondary metabolites scaffolds in the extract. RESULTS: In the YES, the extract stimulated the transactivation of the estrogen receptor in a dose-dependent manner with an EC50 value of 1.8 µg/mL. In rats, E. excelsa increased uterine wet weight, uterine epithelial height, and the mRNA expression of estrogen-responsive genes in the uterus and liver at 50 whereas at 100 mg/kg BW/d anti-estrogenic effects were observed. In the MTT-assay, a dose-dependent decrease of the viability of both cell lines was observed with EC50 values of 13.6 µg/mL (MCF-7) and 27.7 µg/mL (HT-29). The phytochemical analysis revealed that the extract is rich in isoflavonoids, mainly prenylated and pyran-derivatives thereof. CONCLUSION: Erythrina excelsa is rich in prenylated and pyran-substituted isoflavonoids, exhibits estrogenic/anti-estrogenic and cytotoxic effects and warrant sufficient interest for deeper investigations.
