Objective To study the effect of plant Coleus forskohlii active elements Isoforskolin(ISOF)and CT-E(analogs mixture of Isoforskolin)on human neutrophill(PMN)in vitro in order to uncover the mechanism of their properties of mitigating acute lung injury(ALI).Method The effects of ISOF and CF-E on PMN aggregation induced by N-formyl-methiony-leucyl-phenylalanine(fMLP)was performed by using a 4-channel platelet aggregometer.Cytometry Was applied to analyze the effect of tested samples on adhension between PMN and endothelial cells(ECV-304)activated by using lipopolysaccharides(LPS).Expression of LPS-induced PMN adhension molecules was determined with flow cytometry.Radioimmunoassay Was applied to detect the level of TNT-α liberated bv PMN and intracellular cyclic adenosine monophosphate(cAMP)level of PMN.Results It was found that ISOF(25,50,100 μmnol/L)and CF-E(1.25,2.5,5 mg/ml)inhibitted PMN aggregation induced by fMLP,PMN adhemion to ECV-304 indeed by LPS,expression of PMN adhesion molecules,and TNF-α level released by PMN.ISOF and CF-E also increased intracellular cAMP level of PMN.Condusions ISOF and CF-E inhibit PMN aggregation,adhension and adhension molecules,and TNF-α released by PMN,while they increase intracellular cAniP level of PMN.It suggests that their specific alleviating the ALI by the mechanism of the modulation of PMN function.