Pistacia weinmannifolia root exerts a protective role in ovalbumin-induced lung inflammation in a mouse allergic asthma model

Pistacia weinmannifolia (Anacardiaceae) has been used in herbal medicine for the treatment of influenza, dysentery and enteritis in China. It was recently observed that P. weinmannifolia root extract (PWRE) exerts anti-inflammatory effects both in in vitro and in vivo models. Based on the results from previous studies, the present study investigated the protective effect of PWRE on airway inflammation and mucus hypersecretion. Treatment with PWRE significantly decreased the number of eosinophils and the levels of Th2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13, in the bronchoalveolar lavage fluid (BALF) of OVA-exposed mice. PWRE decreased the high serum levels of total and OVA-specific immunoglobulin E. PWRE also effectively inhibited the influx of inflammatory cells into the lung, as well as airway mucus hypersecretion. In addition, the increased level of monocyte chemoattractant protein-1 was significantly decreased with the PWRE treatment in the BALF of OVA-exposed mice and in lipopolysaccharide-stimulated RAW264.7 macrophages. These protective effects of PWRE on OVA-induced pulmonary inflammation were accompanied by the downregulation of mitogen associated protein kinases and nuclear factor-κB activation. Thus, the results from the present study indicate that PWRE could be valuable adjuvant for the treatment of asthma.