Inhibition of mast cell-dependent anaphylactic reactions by the pigment of Polygonum tinctorium (Chung-Dae) in rats.

1. The effect of the pigment obtained from the stem and leaf of Polygonum tinctorium Loar (PtP) on anaphylactic reactions was studied in rats. 2. PtP totally inhibited compound 48/80-induced anaphylactic shock with doses of 10(2) and 10(3) mg/ kg. When PtP was pretreated at concentrations ranging from 10(-2) to 10(3) mg/kg, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. 3. We also investigated the effect of PtP on mast cell-dependent passive cutaneous anaphylaxis (PCA) activated by anti-dinitrophenyl (DNP) IgE antibody. PtP potently inhibited PCA when administered orally, topically, intraperitoneally and intradermally. However, it did not show inhibitory activity when administered intravenously. 4. PtP inhibited dose dependently histamine release from rat peritoneal mast cells (RPMCs) induced by compound 48/80 and anti-DNP IgE. Moreover, the level of cAMP in RPMC, when PtP was added, significantly increased about 12-fold at 4 min compared with that of basal cells. 5. These results indicate that PtP may possess strong antianaphylactic activity and suggest that differences in bioavailability may cause differential activity following different administration routes.