Preventive effects of Impatiens balsamina on the hen egg-white lysozyme (HEL)-induced decrease in blood flow.

Monitoring the blood flow of unanesthesized mice was found to be a reliable and effective method for studying their anaphylactic responses, in addition to the known method of monitoring blood pressure. Hen egg-white lysozyme (HEL)-specific anaphylaxis in mice was estimated by monitoring the decrease in blood flow with a Doppler blood flow meter. This method is convenient for searching for both anaphylaxis and anti-anaphylactic substances from natural products. Using this system, we estimated the anti-anaphylactic effects of the 35% ethanol extract (IB) of petals of Impatiens balsamina L., as well as those of anti-allergic agents currently used. Kaempferol 3-rutinoside and lawsone from IB significantly inhibited the decrease of blood flow. We also found that platelet-activating factor (PAF) and serotonin participate in decreasing the blood flow, but histamine does not.