Protective Effects of Total Alkaloids from Menispermum dauricum against Airway Inflammation in Asthmatic Mice

Abstract

<i>Menispermum dauricum</i> is widely used to treat respiratory inflammation, including laryngopharyngitis, tonsillitis, tracheitis, and bronchitis. Total alkaloids isolated from <i>M. dauricum</i> have shown a variety of beneficial bioactivities. However, available data on the effects of <i>M. dauricum</i> total alkaloids against allergic asthma has not been reported. In present study, the protective effect of <i>M. dauricum</i> total alkaloids was evaluated by using an ovalbumin-induced <i>in vivo</i> model of asthma. The asthma model was prepared by sensitizing and challenging mice with ovalbumin, and <i>M. dauricum</i> total alkaloids (100, 200, and 400 mg/kg) were administrated to asthmatic mice by gavage. Histopathological analysis of pulmonary changes was detected by hematoxylin and eosin, and periodic acid-schiff staining. Inflammatory cell counts were determined in bronchoalveolar lavage fluid. Total immunoglobulin E and ovalbumin-specific immunoglobulin E levels in serum, and T-helper 2 cytokines and chemokine levels in bronchoalveolar lavage fluid were detected by an ELISA. Histological results demonstrated that <i>M. dauricum</i> total alkaloids significantly attenuated pulmonary inflammation in asthmatic mice. <i>M. dauricum</i> total alkaloid treatment exhibited marked effects on asthmatic mice in reducing inflammatory cell counts, decreasing interleukin-4, interleukin-5, and interleukin-13 concentrations, and downregulating TNF-<i>α</i> and eotaxin levels in bronchoalveolar lavage fluid. In addition, <i>M. dauricum</i> total alkaloids could also inhibit the elevated serum levels of total immunoglobulin E and ovalbumin-specific immunoglobulin E. These findings confirmed that <i>M. dauricum</i> total alkaloids could suppress airway inflammation in ovalbumin-induced asthma through regulating the T-helper 2 response and chemokine level. <i>M. dauricum</i> total alkaloids may be a potential ethnopharmacological agent for asthmatic patients.