Stimulatory effects of ingenols from Euphorbia kansui on the expression of macrophage Fc receptor.

Immune complex binding to macrophages was enhanced by treatment with an E. kansui extract. Systematic fractionation of the extract led to the characterization of 3-O-(2'E,4'Z-decadienoyl)- and 3-O-(2,3-dimethylbutyryl)-13- O-n-dodecanoyl-13-hydroxyingenol as the active principles. Immune complex binding to macrophages by the action of these compounds increased in a dose-dependent manner. When each ingenol (10 nM) was added to the separated culture medium, the immune complex binding ability of macrophages increased up to 2-fold, respectively. Scatchard analysis showed the enhanced expression of the Fc-receptor for gamma-globulin by the action of each ingenol to macrophages. This Fc-receptor upregulation was dependent on RNA synthesis, suggesting a possible de novo synthesis.