Inhibition of histamine release from rat mast cells by the plant alkaloid tetrandrine.

The plant alkaloid tetrandrine was shown to have significant inhibitory effects on receptor-ligand-mediated histamine release from rat mast cells at concentrations similar to or lower than that observed with theophylline and sodium cromoglycate. Inhibition of histamine release did not occur when non-specific stimulants such as aspirin, A23187 or adenosine triphosphate were used. Inhibition of ovalbumin-IgE and concanavalin A-mediated histamine release was reversible by washing the cells, showing that tetrandrine does not bind tightly to the cell membrane or cytoplasmic components. These results, taken together with previous reports of its anti-phagocytic, anti-oxidant and immunosuppressive properties, suggest that tetrandrine may be a broad spectrum non-steroidal drug of potential value in the treatment of allergic diseases.