Cinnamaldehyde is a principle compound isolated from
Guizhi-Tang, which is a famous traditional Chinese medical formula used to treat
influenza,
common cold and other pyretic conditions. The aim of the present study was to investigate the effects of
cinnamaldehyde on expression and activity of
cyclooxygenase (COX) and
prostaglandin E(2) (
PGE(2)) in rat cerebral microvascular endothelial cells (RCMEC). RCMEC were cultured, and identified by immunohistochemistry for
von Willebrand factor in cytoplasm of the cells. Then cells were incubated in M199 medium containing
interleukin (IL)-1beta in the presence or absence of
cinnamaldehyde. After incubation, the medium was collected and the amount of
PGE(2) was measured by
enzyme-linked
immunosorbent assay (ELISA). The cells were harvested,
mRNA expression and activity of COX were analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR) with
SYBR Green dye and ELISA respectively. Positive immunostaining for
von Willebrand factor was present diffusely in the cytoplasm of >95% RCMEC. IL-1beta increased the
mRNA expression and activity of COX-2, and production of
PGE(2) in a dose- and time-dependent manner in RCMEC, while
mRNA and activity of COX-1 were not significantly altered.
Cinnamaldehyde significantly decreased IL-1beta-induced COX-2 activity and
PGE(2) production in a dose-dependent manner, while it showed no inhibitory effect on IL-1beta-induced COX-2
mRNA expression in cultured RCMEC. In conclusion,
cinnamaldehyde reduces IL-1beta-induced COX-2 activity, but not IL-1beta-induced COX-2
mRNA expression, and consequently inhibits production of
PGE(2) in cultured RCMEC.