Anti-allergic and anti-inflammatory effects of aqueous extract of Pogostemon cablin

Abstract

Allergic disease is caused by exposure to normally innocuous substances that activate mast cells. Mast cell-mediated allergic inflammation is closely related to a number of allergic disorders, such as anaphylaxis, allergic rhinitis, asthma and atopic dermatitis. The discovery of drugs for treating allergic disease is an interesting subject and important to human health. The aim of the present study was to investigate the anti-allergic and anti-inflammatory effects of the aqueous extract of Pogostemon cablin (Blanco) Benth (AEPC) (a member of the Labiatae family) using mast cells, and also to determine its possible mechanisms of action. An intraperitoneal injection of compound 48/80 or a serial injection of immunoglobulin E and antigen was used to induce anaphylaxis in mice. We found that AEPC inhibited compound 48/80-induced systemic and immunoglobulin E-mediated cutaneous anaphylaxis in a dose-dependent manner. The release of histamine from mast cells was reduced by AEPC, and this suppressive effect was associated with the regulation of calcium influx. In addition, AEPC attenuated the phorbol 12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated expression of pro-inflammatory cytokines in mast cells. The inhibitory effects of AEPC on pro-inflammatory cytokines were dependent on the activation of nuclear factor (NF)-kappa B and p38 mitogen-activated protein kinase (MAPK). AEPC blocked the PMACI-induced translocation of NF-kappa B into the nucleus by hindering the degradation of I kappa B alpha and the phosphorylation of p38 MAPK. Our results thus indicate that AEPC inhibits mast cell-mediated allergic inflammation by suppressing mast cell degranulation and the expression of pro-inflammatory cytokines caused by reduced intracellular calcium levels and the activation of NF-kappa B and p38 MAPK.