Objective: To compare the effects of 6 phenylallyl compounds on cyclooxygenase-2（COX-2） and prostaglandin synthase（PGES） mRNA expression

and provide some evidence for their structure-activity relationship.Method: Macrophages stimulated by lipopolysaccharide（LPS） model was used to test the effects of cinnamic alchohol

O-methoxy cinnamic alchohol

cinnamaldehyde

O-methoxy cinnamaldehyde

cinnamic acid and O-methoxy cinnamic acid on COX-2 and PGES at mRNA level.The RAW264.7 cells was treated with 1 mg·L-1 LPS and phenylallyl compounds（0

12

19

32

54

90

150 mg·L-1） for 4 h

and the mRNA was detected by TaqMan real time PCR.Result: The cinnamaldehyde had the strongest effect

showed significant effect on COX-2（P<0.05） and membrane-associated PGES-1（mPGES-1）（P<0.01） at 32 mg·L-1.The O-methoxy cinnamaldehyde took second place

showed significant effect on COX-2（P<0.05） and mPGES-1（P<0.05） at 54 mg·L-1.The other 4 phenylallyl compounds had effects in different degree

but was much weaker than cinnamaldehyde and O-methoxy cinnamaldehyde.Conclusion: It is key mechanism of anti-inflammatory and antipyretic for the phenylallyl compounds to down-regulate PGE2 production by inhibiting COX-2 and mPGES-1.The efficacy of the phenylallyl compounds was aldehyde>alcohol>acidum

and it is degraded by the methoxyl.The action intensity may be closely related to the different oxidation state of propenyl and impacted by methoxyl.