It is interesting that the authors further developed biochemical and structual studies to support and extend their earlier work that reported increase of COX-2 activity by quercetin and certain other flavonoids. However, overwhelming evidence have indicated that flavonoids inhibit COX-2 expression, and overall production of PGE2, during inflammation. Therefore, despite the increase in catalytic activity, the reduction in amount apparently overwhelmed this activity. The author should have addressed this and propose the potential importance of this finding with regards to inflammation.
Another aspect is the potential difference between in vitro biochemical assay and in vivo scenario, where flavonoids exist mostly in glycosylated and other conjugated form, instead of aglycone. Perhaps the interaction between quercetin etc. and cox would be altered during in vivo metabolism.
