Cinnamaldehyde and 2-methoxycinnamaldehyde as NF-κB inhibitors from Cinnomomum cassia

Nuclear factor (NF)-kappaB is a transcription factor regulating the expression of inflammatory and immune genes. In the present study, an extract from stem bark of Cinnamomum cassia Blume (Lauraceae) was discovered to have an inhibitory effect on LPS-induced NF-kappaB transcriptional activity, which was determined using macrophages RAW 264.7 transfected stably with an alkaline phosphatase reporter construct containing four copies of the NF-kappaB binding kappaB sequence. Following activity-guided fractionation, trans-cinnamaldehyde and 2-methoxycinnamaldehyde were identified as the NF-kappaB inhibitors from C. cassia with IC50 values of 43 muM and 31 muM, respectively. As a positive control, caffeic acid phenethyl ester (CAPE) showed an IC50 value of 2 muM on NF-kappaB transcriptional activity. Both trans-cinnamaldehyde and 2-methoxycinnamaldehyde inhibited LPS-induced DNA binding activity of NF-kappaB in addition to NF-kappaB transcriptional activity.