Abstract: To investigate the anti-inflammatory activities of Forsythia suspensa extract (FSE) with emphasis on excretion of inflammatory cytokines by LPS-induced BEAS-2B inflammation model.BEAS-2B cell viability was detected by MTT method in order to screen out the optimal drug dose of F.suspensa ethanol extracts (FSEE),60% forsythiaside A (60% FTA) extracts and 90% forsythiaside A (90% FTA) extracts;The morphology of BEAS-2B cells treated with FSE were observed by microscope; NO content of cell culture supernatant was determined by Griess Reagent method;Intracellular reactive oxygen species (ROS) was analyzed by flow cytometry.Toxical experimental results revealed that FSE did not show toxic reaction to BEAS-2B cell at concentration of less than 128 μg/mL;while both 60% FTA and 90% FTA showed toxicity at the concentration between 128 and 256 μg/mL.Anti-inflammatory results showed that all FSE can inhibit the secretion of NO (P<0.01) at concentration 25,50,and 100 μg/mL,and 90% FTA extracts exhibited a dose-dependent manner;The elevated level of intracellular ROS in LPSstimulated BEAS-2B cells was significantly diminished by all FSE in a dose-effect manner (P<0.05).In addition,the therapeutic effect of FSEE,60% FTA and 90% FTA increased gradually.It was concluded that the 90% FTA extracts were the main active fraction of anti-inflammatory effect and forsythiaside A was possibly the active ingredient.The results presented in this study will be helpful for the further study of F.suspensa on anti-inflammatory activity.

Key words: Forsythia suspensa extract, forsythiaside A, human airway epithelial cells, inflammation model, lipopolysaccharide