Antianaphylactic and antipruritic effects of the flowers of Impatiens textori MIQ.

The anti-anaphylactic and anti-pruritic activities of a 35% EtOH extract (IT) of the flowers of Impatiens textori MIQ. were investigated by in vivo assay. IT and apigenin (1), apigenin 7-glucoside (2) and luteolin (3), principal compounds from IT, inhibited compound 48/80 (COM)-induced by blood pressure (BP) decrease, which was an immunoglobulin (Ig)E-independent anaphylaxis-like response. Compounds 1-3 all inhibited BP decrease induced by IgE-dependent anaphylaxis. Furthermore, IT also inhibited the blood flow (BF) decrease induced by antigen-induced anaphylaxis in actively sensitized mice. IT showed a significant inhibitory effect on scratching behavior induced by COM without a central depressant. IT also significantly inhibited platelet activating factor (PAF)- and serotonin (5-HT)-induced scratching behavior and mitigated protease (PA)-induced scratching behavior. These findings showed that the flowers of I. textori can be utilized as an anti-anaphylactic and anti-pruritic agent in addition to the traditional applications of this plant.