Anti-allergic activity of some selected plants in the Zingiberaceae family.

Ethanolic and water extracts, together with volatile oils from the rhizomes of six selected Zingiberaceous plants, including Curcuma mangga, Kaempferia galanga, Kaempferia parviflora, Zingiber cassumunar, Zingiber officinale and Zingiber zerumbet were investigated for their anti-allergic activities using a RBL-2H3 cell line. The ethanolic (EtOH) extract of Kaempferia parviflora exhibited the most potent anti-allergic effect against antigen-induced beta-hexosaminidase release as a marker of degranulation in RBL-2H3 cells, with an IC(50) value of 10.9 microg/ml, followed by Zingiber cassumunar (EtOH, IC(50)=12.9 microg/ml) and Curcuma mangga (water, IC(50)=36.1 microg/ml). The volatile oils of these six plants were apparently inactive (IC(50)>100 microg/ml). The crude extracts were also tested on beta-hexosaminidase activity to clarify whether their effects were due to the inhibition of enzyme activity or of degranulation. As a result, the plant extracts were inactive against the enzyme activity of beta-hexosaminidase. These findings support the use in Thai traditional medicine of these selected Zingiberaceous plants, especially Kaempferia parviflora and Zingiber cassumunar, for treatment of allergy and allergic-related diseases.