CTB glycoprotein (75 kDa) inhibits IgE releasing, TNF-α and IL-6 expressed by bisphenol A in vivo and in vitro

Cudrania tricuspidata Bureau (CTB) has been used to treat allergies and inflammatory disease as folk medicine in Korea. The objective of this study is to determine whether a glycoprotein isolated from CTB (75 kDa) has a preventive potential of allergic inflammation caused by bisphenol A (BPA) in BALB/c mice and RBL-2H3 cells. Production of immunoglobulin (Ig) E and releasing of β-hexosaminidase and histamine at treatment of CTB glycoprotein (5–10 mg/kg, BW) were evaluated in mice serum. Activation of extracellular signal-regulated kinases (ERK) and p38 mitogen-activated protein kinase (MAPK), activator protein (AP)-1, expressions of pro-inflammatory cytokines, nitric oxide (NO) production and cyclooxygenase (COX)-2 were assessed in RBL-2H3 cells. In the results, CTB glycoprotein (10 mg/kg, BW) inhibited the production of IgE and releasing of β-hexosaminidase and histamine. Also, the CTB glycoprotein (100 μg/ml) blocked phosphorylation of ERK1/2 and p38 MAPK, and the activation of AP-1, while it inhibited the NO production, activities of COX-2, tumor necrosis factor (TNF)-α, and interleukin (IL)-6, but not IL-1β. Taken together, the results of this study indicated that the CTB glycoprotein modulates the expression of allergic inflammation-related factors via the suppression of MAPK/AP-1 activation.