Inhibition of IgE/antigen- and ionophore-induced mucosal mast cells degranulation by Alpinia galangal and acetoxychavicol acetate

Abstract

Background Many researches have now demonstrated the stimulation of mucosal mast cells by both allergic and nonallergic triggers and their inhibition as a potential therapeutic target in several diseases in which effective therapeutic agents have not been developed like food allergy and ulcerative colitis. Hence we screened medicinal plants from Pakistan against antigen and ionophore induced degranulation of mucosal mast cells.

Materials Aqueous ethanol extracts of Pakistani medicinal plants were prepared and screened in the assays. IgE and A23187 induced degranulation of mucosal type murine bone marrow derived mast cells (mBMMCs) were employed as screening assays and beta hexosaminidase released from degranulated mBMMCs was measured. Real time polymerase chain reaction was employed to examine the expression of tumor necrosis factor alpha and interleukin 4 mRNA. Acetoxychavicol acetate a major chemical constituent of Alpinia galangal was also examined by degranulation assay and real time PCR.

Results Among the ten plants screened against IgE stimulated degranulation only Alpinia galangal demonstrated significant suppression of the degranulation at both concentration of 32 microgram per ml and 100 microgram per ml. In A23187 induced degranulation all plants showed significant inhibition at 100 microgram per ml except Tamarix dioica while Alpinia galangal exhibited significant suppression at 32 microgram per ml. In a concentration dependent assay Alpinia galangal revealed significant suppression at 10 microgram per ml against A23187 stimulated degranulation. Acetoxychavicol acetate demonstrated significant inhibition at 3.2 micromole in IgE antigen treated cells and at 10 micromole in A23187 treated cells. Furthermore both Alpinia galangal and acetoxychavicol acetate significantly suppressed the IgE antigen and A23187 enhanced mRNA expression of inflammatory cytokines TNF alpha and IL4 in mBMMCs.

Conclusion Our findings revealed for the first time the suppressive effect of Alpinia galangal and acetoxychavicol acetate on degranulation of mBMMCs and expression of TNF alpha and IL4 induced by allergic and non allergic stimuli. Alpinia galangal and acetoxychavicol acetate may become lead candidates in the treatment of diseases caused by pathological activation of mucosal mast cells like food allergy and ulcerative colitis.