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. hsi en Ting (OSI-IT) on anaphylaxis. OSHT (0.001-1.0 mg g(-1) body 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(-1) BW, the serum histamine levels were reduced in a dose-dependent manner. OSHT (0.001-1.0 mg g(-1) BW) also inhibited local anaphylaxis acti vated by anti-dinitrophenyl (DNP) IgE. Moreover, OSHT dose-dependently inhi bited 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 w as added, significantly increased approx. 20-fold compared with that of bas al cells. These results indicate that OSHT possesses strong antianaphylacti c activity by inhibition of histamine release from mast cells in vivo and i n vitro. (C) 1999 Academic Press.