Quercetin 3,7,3',4'-tetrasulphated isolated from Flaveria bidentis inhibits tissue factor expression in human monocyte.

Sulphated esters of the flavonoids sulphated quercetin 3,7,3',4'-tetrasulphated (QTS) and quercetin 3-acetyl-7,3,4'-trisulphate (ATS), isolated from Flaveria bidentis, have demonstrated anticoagulant and antiplatelet properties. In this study, we examined if both compounds affected the expression of the procoagulant tissue factor (TF) induced by lipopolysaccharide (LPS) on human monocyte. Monocytes were pretreated with different concentrations of each flavonoid (0.1-500 μM), followed by a 4h incubation with LPS in order to induce TF expression. Results of the TF expression showed different behaviors for the two flavonoids studied. A slight inhibitory effect on the TF expression was detected at a QTS concentration of 0.1 μM, but from 1 μM onwards a significant inhibitory effect that remained up to 500 μM could be observed. In contrast, ATS induced a poor inhibitory effect on TF expression at all concentrations tested. These results suggest that QTS has another antithrombotic property, to be added to its already renowned ability as an anticoagulant and antiplatelet compound.