Saururus chinensis water-extract effectively controls asthma by ameliorating of Th1/Th2 imbalance and suppressing of NF-κB/COX-2/PGE2-related inflammation

•S. chinensis had two important and explicit anti-asthmatic pathways; one was to decrease the upregulated Th2-related factors and the other was to inhibit inflammation.•S. chinensis suppressed the release of Th2-related cytokines such as IL-4 and IL-5 by down-regulating the expression level of Th2 cell transcription factor, GATA-3.•S. chinensis controlled inflammation via ERK-NF-κB/COX-2-PGE2 pathway.•S. chinensis has been used as culinary material in the East north Asia.