The evaluation of the antianaphylactic effect of Oryza sativa L. subsp. hsien Ting in rats.

We studied the effect of the methanol extract of Oryza sativa L. subsp. hsien Ting (OSHT) on anaphylaxis. OSHT (0.001-1.0 mg g-1body weight (BW)) dose-dependently inhibited systemic anaphylaxis induced by compound 48/80 in rats. When OSHT was pretreated at concentrations ranging from 0.001 to 1.0 mg g-1BW, the serum histamine levels were reduced in a dose-dependent manner. OSHT (0. 001-1.0 mg g-1BW) also inhibited local anaphylaxis activated by anti-dinitrophenyl (DNP) IgE. Moreover, OSHT dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cAMP in RPMC, when OSHT was added, significantly increased approx. 20-fold compared with that of basal cells. These results indicate that OSHT possesses strong antianaphylactic activity by inhibition of histamine release from mast cells in vivo and in vitro.