Immunostimulatory Activity of Isoflavone-Glycosides and Ethanol Extract from a Fermented Soybean Product in Human Primary Immune Cells

Sasang constitutional medicine is a major branch of Korean traditional oriental medicine. Constitutions of Sasang medicine are classified into Taeyangin, Taeumin, Soyangin, and Soumin. We investigated immunostimulatory activities of fermented soybean product (FSP) extracts and their major bioactive compounds, isoflavone glycosides in primary immune cells isolated from the blood of Soyangin, Taeumin, and Soeumin volunteers. Results showed that the cell proliferation, nitrite, tumor necrosis factor (TNF)-α mRNA, interleukin (IL)-6 mRNA, inducible nitric oxide synthase (iNOS) mRNA, cyclooxygenase-2 (COX-2) mRNA, TNF-α protein, and IL-6 protein production of immune cells treated with a 70% ethanol Doenjang extract (DJ), a 70% ethanol Kochujang extract (KCJ), and a 70% ethanol Cheonggukjang extract (CGJ), respectively, were significantly increased, and its immunostimulatory activities by both DJ and CGJ was higher than that of KCJ in primary immune cells isolated from the blood of Soyangin volunteers. However, the cell proliferation, nitrite, TNF-α mRNA, IL-6 mRNA, iNOS mRNA, COX-2 mRNA, TNF-α protein, and IL-6 protein production by both KCJ and CGJ was higher than that of DJ in primary immune cells isolated from the blood of Taeumin and Soeumin volunteers. The major bioactive compounds, isoflavone-glycosides, in FSP were daidzin, glycitin, and genistin. Daidzin, glycitin, and genistin were used to treat primary immune cells in the same condition, the cell proliferation; iNOS mRNA expression and nitrite concentration of daidzin, glycitin, or genistin-treated immune cells isolated from the blood of Soyangin volunteers was higher than that of Taeumin and Soeumin volunteers. The effect of DJ and isoflavone glycosides on immunostimulatory activities showed similar trends.