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

Menispermum dauricum is widely used to treat respiratory inflammation, including laryngopharyngitis, tonsillitis, tracheitis, and bronchitis. Total alkaloids isolated from M. dauricum have shown a variety of beneficial bioactivities. However, available data on the effects of M. dauricum total alkaloids against allergic asthma has not been reported. In present study, the protective effect of M. dauricum total alkaloids was evaluated by using an ovalbumin-induced in vivo model of asthma. The asthma model was prepared by sensitizing and challenging mice with ovalbumin, and M. dauricum 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 M. dauricum total alkaloids significantly attenuated pulmonary inflammation in asthmatic mice. M. dauricum 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-α and eotaxin levels in bronchoalveolar lavage fluid. In addition, M. dauricum total alkaloids could also inhibit the elevated serum levels of total immunoglobulin E and ovalbumin-specific immunoglobulin E. These findings confirmed that M. dauricum total alkaloids could suppress airway inflammation in ovalbumin-induced asthma through regulating the T-helper 2 response and chemokine level. M. dauricum total alkaloids may be a potential ethnopharmacological agent for asthmatic patients.