EFFECT OF THE AQUEOUS EXTRACT OF AQUILARIA-AGALLOCHA STEMS ON THE IMMEDIATE HYPERSENSITIVITY REACTIONS

We investigated the effects of the aqueous extract of Aquilaria agallo cha Roxb. (Thymelaeaceae) on the immediate hypersensitivity reactions. The aqueous extract of Aguilaria agallocha stems showed inhibitory ef fects on passive cutaneous anaphylaxis, anaphylaxis induced by compoun d 48/80, and histamine release from rat peritoneal mast cells (RPMC). The morphological examination also clearly showed that the extract pre vented the degranulation of RPMC in rats. The level of compound 48/80- induced intracellular cAMP in RPMC, when the extract was added, signif icantly increased about 8-fold at 10 s compared with that of basal cel ls. These results suggest that the aqueous extract of Aquilaria agallo cha stems inhibits the immediate hypersensitivity reaction by inhibiti on of histamine release from mast cells. (C) 1997 Elsevier Science Ire land Ltd.