Abstract: In order to investigate the action of traditional Chinese medicine on tumor multidrug resistance,the inhibition activities of curcumin,sinomenine,vitexin,and celery on COX-2 (cyclooxygenase-2) versus COX-1 (cyclooxygenase-1) were determined by in vitro enzymatic reaction experiments,using the selective index (COX-1 IC50/ COX-2 IC50) to evaluate the selective inhibition activity against COX-2.The experimental results indicated that the selectivity index values of the four compounds against COX-2 are 128.71 for vitexin,16.24 for curcumin,8.45 for apigenin,and 3.55 for sinomenine,respectively.For molecular docking,the comparison of the four compounds for the docking molecule enzyme binding energy and docking molecules internal energy in the related molecular docking data was firstly used to evaluate the selective inhibition activity of the four compounds against COX-2.The molecular docking results are consistent with the in vitro enzymatic reaction results,which show that vitexin is more potent than other compounds against COX-2.These findings suggest that vitexin is the optimal compound which can be used as the lead compound for a new COX-2 inhibitors with more selective activity.

Key words: molecule docking, natural products, cyclooxygenase-2, selective inhibition, tumor-multidrug resistance