[The effect of sinomenine on cyclooxygenase activity and the expression of COX-1 and COX-2 mRNA in human peripheral monocytes].
OBJECTIVE
To observe in vitro the effect of Sinomenine, a pure alkaloid extracted from the chinese medical plant Sinomenium acutum on the activity of cyclooxygenase (COX-1 and COX-2) and the expression of COX-1 and COX-2 mRNA.


METHODS
Mononuclear leukocytes were obtained from healthy adults. Isolated mononuclear leucocytes from human peripheral blood (PBMC) were incubated (1 x 10(6).mL-1) with or without sinomenine (or indomethacin), after incubated for 24 hours at 37 degrees C with 5% CO2; the media were assayed for the PGE2 by radioimmunoassay (RIA). LPS was used to stimulate the monocytes at a concentration of 5 micrograms.mL-1. And by RT-PCR, both COX-1 and COX-2 mRNAs were detected in Mononuclear leukocytes after incubation for different hours with drug (sinomenine or indomethacin) or not.


RESULTS
LPS (stimulated) induced the production of PGE2 in PBMC increasing with high expression of COX-2 mRNA; sinomenine reduced PGE2 production in LPS stimulated human monocytes more than in non-stimulated human monocytes. In comparative experiments, indomethacin, a non selective COX inhibitor, reduced the production of PGE2 equally in both states. Meanwhile, neither sinomenine(0.1-1 mmol.L-1) nor indomethacin(0.5-10 mumol.L-1) inhibited the expression of both COX-1 and COX-2 mRNAs by RT-PCR with beta-actin as reference.


CONCLUSIONS
In contrast with indomethacin, Sinomenine shows a preferential inhibitory effect on COX-2 over COX-1, These results suggest that Sinomenine is a selective COX-2 inhibitor, which may be directly related to suppressing cyclooxygenase activity.
Wang
Wen-jun
WJ
Laboratory of Immunology, Guangzhou University of Traditional Chinese Medicine, Guangzhou 510405, Guangdong, China.
Wang
Pei-xun
PX
Li
Xiao-juan
XJ
D000328:Adult; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000097:blood; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000201:enzymology*; D008565:Membrane Proteins; D009019:Morphinans / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D032841:Sinomenium / Q000737:chemistry
D007527:Isoenzymes; D008565:Membrane Proteins; D009019:Morphinans; D012333:RNA, Messenger; C009271:sinomenine; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone