Effects of 70% methanol extract obtained from Moutan Cortex (the root cortex of Paeonia moutan SIM., Paeoniaceae), which is one of the most important crude drugs in traditional Chinese medicine, on the phagocytic activity of the mouse resiculoendotherial system were studied by the carbon clearance method in vivo. Cell numbers of peritoneal exudate cells solution and phagocytosis of latex by peritoneal macrophage (Mφ) were also examined in vitro. The clearance-rate of carbon was significantly shortened 1 h after the administration of 70% methanol extract (400mg/kg, p.o.). Microscopically, carbon particles were internalized by Mφ of marginal zones between white and red pulp in the spleen, and in the liver, mainly by Kupffer cells. The 70% methanol extract activated the phagocytosis of carbon by Kupffer cells in the liver. Cell numbers of peritoneal exudate cells solution increased 24 h after the administration of 70% methanol extract (400mg/kg, p.o.). The incubation of 70% methanol extract (100μg/ml) with peritoneal Mφ promoted the phagocytosis of latex by peritoneal Mφ. These results suggest that 70% methanol extract obtained from Moutan Cortex promotes the phagocytic activity on the reticuloendotherial system in mice and that it has a stimulatory effect on Mφ because of an increase in cell numbers of peritoneal exudate cells solution and of phagocytic activity of peritoneal Mφ.
