Long-term oral administration of Gynostemma pentaphyllum extract attenuates airway inflammation and Th2 cell activities in ovalbumin-sensitized mice

Our previous report demonstrated that the oral administration of short-term high dose Gynostemma pentaphyllum extract (5 g/kg per day for 7 days) decreased allergic reactions in ovalbumin (OVA)-sensitized mice. The aim of this study was to determine whether long-term oral administration of G. pentaphyllum attenuated airway inflammation in OVA-sensitized mice.Mice were sensitized and challenged with normal saline or OVA. OVA-sensitized mice were fed with 1.75 g/kg (low dose, GPL) or 5 g/kg (high dose, GPH) G. pentaphyllum extract, five days a week for 4 weeks. The airway hyperresponsiveness (AHR) and eosinophilia in bronchoalveolar lavage fluid (BALF) were examined. The cytokine levels or antibodies in BALF, serum and spleen cell culture supernatants were also determined. Both high and low dose extracts reduced AHR, serum OVA–IgE, and Th2-associated cytokine levels in spleen cell supernatants and BALF in OVA-sensitized mice. These results show that long-term orally administered G. pentaphyllum extract reduced allergic reactions in OVA-sensitized mice.