Estrogenic activity of fermented soymilk extracts and soy compounds

To understand the complex mechanism of estrogen action, multiple assays based on different biological principles is important. Here, multiple assays based on cell, protein and transcription assays were used to evaluate estrogenic activity of soymilk extracts before and after fermentation, and four soy compounds, genistein and daidzein, and their glycosides, genistin and daidzin, respectively. The data obtained by a transcription assay, RNA-sequencing (RNA-seq), was further examined by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis to understand cell functions, i.e. biological processes and metabolic pathways. Among the cell functions identified, the sets of genes for cell division/cell cycle and DNA replication/DNA repair are significantly up-regulated, whereas those for autophagy are significantly down-regulated, which explains well the enhanced activity of cell proliferation by these materials. The applications of estrogenic activity of soymilk extracts and soy flavonoids, and the contribution of fermentation, include pharmacological benefits, such as bone protection/bone regeneration, cancer chemoprevention, neuroprotection and the treatment of menopausal syndromes. MCF-7 cells at a density of 1.0×106 cells per well were cultured in RPMI1640 supplemented with 10% DCC-FBS for 3 days under the conditions of 37°C in 5% CO2. The cells were treated in RPMI1640 supplemented with 10 nM E2, 10 µg/ml unfermented soymilk extracts (Yellow or Black Soybean), 10 µg/ml fermented soymilk extracts (Yellow or Black Soybean), 10 µM genistin, 10 µM genistein, 10 µM daidzin, 10 µM daidzein or 0.1% DMSO (vehicle) for 3 more days.