Abstract: In order to observe the relaxation effects of total Yulangsan water extract (TYLS),and three purified components of Yulangsan,namely flavonoid,saponin and polysaccharide on guinea pig tracheal smooth muscle,the fresh piece of guinea pig trachea was prepared.The contraction model of the isolated guinea pig trachea was induced by histamine (His) or acetylcholine (ACh) in the Krebs’ buffer solution.Different concentrations of TYLS and three components were then applied on the contractive tracheal model.The results showed that TYLS,saponin and polysaccharide markedly relieved the contraction of isolated tracheal smooth muscle of guinea pig induced by His or Ach and the concentration-response curves of His and ACh were shifted rightward.The presented data suggested that TYLS,saponin and polysaccharide can significantly relax the tracheal smooth muscle.

Key words: total Yulangsan water extract, flavonoid, saponin, polysaccharide, isolated trachea