Anti-allergic and anti-anaphylactic activity of picroliv--a standardised iridoid glycoside fraction of Picrorhiza kurroa.

Picroliv, a standardised iridoid glycoside fraction from the root and rhizome of Picrorhiza kurroa at a dose of 25 mg kg-1 p.o. inhibited passive cutaneous anaphylaxis in mice (82%) and rats (50-85%) and protected mast cells from degranulation (60-80%) in a concentration-dependent manner. Its effect was also studied in sensitised guinea pig ileum preparation in vitro (Schultz-Dale study) and in normal guinea pigs in vivo (Konzett-Rossler, in preparation). There was inhibition of the Schultz-Dale response in sensitised guinea pig ileum, but the bronchospasm induced by histamine could not be antagonised or prevented by Picroliv, indicating the absence of a direct post-synaptic histamine receptor blocking activity.