Antiasthmatic potential of Zizyphus jujuba Mill and Jujuboside B. - Possible role in the treatment of asthma.

Zizyphus jujuba Mill, a famous oriental traditional medicine, has been reported to exhibit diverse activities in biological systems including the respiratory system. However, a little information is available on its antiasthmatic activity. Jujuboside B (JB) is a natural saponin and one of the active constituent of fruits of Zizyphus jujuba. In the present investigation, JB was isolated from ethanolic extracts of fruits of Zizyphus jujuba (EZJF). EZJF and JB were then evaluated for anti-asthmatic activity using various screening methods. JB was additionally evaluated using ovalbumin (OVA) -induced allergic asthma in mice. Results obtained in the present study showed that EZJF and JB significantly inhibited clonidine-induced catalepsy, milk-induced leucocytosis and eosinophilia, clonidine-induced mast cell degranulation, and passive paw anaphylaxis. The number of inflammatory cells in bronchoalveolar lavage (BAL) fluid was considerably lowered and the severity of pulmonary inflammation was alleviated in the mice pretreated with JB. The high-level expression of T-helper type 2 (TH2) cytokines was markedly reduced in the serum, BAL fluid, and lung homogenates. Thus EZJF and JB showed potent anti-asthmatic activity. Hence EZJF and JB possess a potential role in the treatment of asthma.