Gynostemma pentaphyllum decreases allergic reactions in a murine asthmatic model

The increasing incidence of asthma in developing countries emphasizes the importance of identifying more effective treatments that have low cost. Gynostemma pentaphyllum (Thunb.) Makino (Cucurbitaceae), a common herbal tea in China, has been used to treat lung inflammation. Since the Th2 cytokines are the major mediators in the pathogenesis of asthma, Th1-biased immune responses caused by G. pentaphyllum might have the potential to relieve asthmatic symptoms. We hypothesized that oral administration of G. pentaphyllum extracts might suppress Th2 cytokine-induced airway inflammation responses in ovalbumin (OVA)-sensitive mice. BALB/c mice were sensitized with intraperitoneal injection and challenged 3 times with OVA inhalation (IH) (the IH3 model). G. pentaphyllum was orally administered for 7 consecutive days before the end of the OVA challenge. In the IH5 model, 2 more OVA challenges were administered to mimic the encounter with an allergen after drug treatment. G. pentaphyllum extracts significantly attenuated airway hyperresponsiveness (AHR) and inhibited eosinophil infiltration in mice in both models. Serum OVA-specific antibodies were also reduced with the treatment. Decreased Th2-type cytokines and increased IFN-gamma were detected in the cultures of OVA-activated splenocytes from treated mice. Our results suggest that G. pentaphyllum extracts might be beneficial for asthma airway inflammation through the suppression of Th2 activity.