NEW YORK (Reuters Health) – Xiao-qing-long-tang (XQLT), a traditional Chinese medicine used to treat bronchial asthma, appears to reduce bronchoconstriction and eosinophil infiltration of the airway, according to the results of an animal study by Taiwanese researchers.
Dr. Shung-Te Kao, from China Medical College, and colleagues studied the effect of XQLT in ovalbumin-sensitized guinea pigs. Both antigen-induced immediate asthmatic response and late asthmatic response were significantly inhibited by XQLT, Dr. Kao's team found.
Also, XQLT produced relaxation of isolated guinea pig trachea that had been precontracted with carbachol. This effect was reversed by a selective beta-2 antagonist.
When the investigators analyzed bronchoalveolar lavage fluid they found that XQLT significantly suppressed the increase in eosinophils in the airway and slowed the increase of eosinophils for up to 72 hours after antigen challenge, according to their report in the December issue of Allergy.
Dr. Kao and colleagues conclude that "we show for the first time that XQLT is effective against early and late phase airflow obstruction in conscious sensitized guinea pigs…and we associated these changes with the number of eosinophils in bronchoalveolar lavage fluid."
"We suggest that there may be two antiasthmatic mechanisms of XQLT, a bronchodilator effect resulting from its stimulation of beta-2-receptors on bronchial smooth muscles, and an ability to inhibit the eosinophil infiltration into the airway."