Inhibitory Effect of Alpiniae officinarum Rhizoma Extract on Degranulation in RBL-2H3 Cells

Abstract

Alpiniae officinarum Rhizoma (the rhizome of Alpinia officinarum Hance, known as lesser galangal), a family of Zingiberaceae, has been used to reduce pain of infection and inflammatory diseases in Asian countries. The present study was focused to evaluate the inhibitory degranulation effect of Alpiniae officinarum Rhizoma extract in RBL-2H3 rat basophilic leukemia cells. Cell viability was measured by MTT assay. RBL-2H3 cells were stimulated by phorbol 12-myristate 13-acetate and calcium ionophore A23187. Mast cell degranulation was analyzed by measuring release of β-hexosaminidase in RBL-2H3 cell. Gene expression was measured by qRT-PCR and signaling molecules were detected by immunoblotting. The Alpiniae officinarum Rhizoma extract suppressed β-hexosaminidase release in dose-dependent manner and inhibited cycloxygenase-2 and tumor necrosis factor-α gene expression. Furthermore, it was found that Alpiniae officinarum Rhizoma extract reduced mitogen-activated protein kinases, especially phosphorylated p38, at 0.75 ㎎/㎖ of Alpiniae officinarum Rhizoma extract concentrations. These data show that Alpiniae officinarum Rhizoma extract has immunosuppressive effect in mast cell induced allergic inflammation.