Licochalcones extracted from Glycyrrhiza inflata inhibit platelet aggregation accompanied by inhibition of COX-1 activity
Fig 6
Competitive inhibition of COX-1 and COX-2 activity by licochalcone A in vitro.
(A) Hematin (2 μM) and L-tryptophan (5 mM) were added to 100 mM Tris-HCl buffer (pH 8.0), then two units of COX-1 or COX-2 and each concentration of licochalcone A (0.5–100 μM) were added and incubated at 37°C for 10 min. The reaction was initiated by adding arachidonic acid (0.5 μM). After 2 min, the reaction was terminated by adding 1.0 M HCl, and then the amount of PGE2 was measured by LC-MS/MS. Results are shown as mean±S.E.M. (*P<0.05 compared with control, n = 3, Dunnett’s method). (B) Two units of COX-1 and licochalcone A (2.5 μM) were incubated at 37°C for 10 min as described above. The reaction was initiated by adding each concentration of arachidonic acid (0.1–10 μM). After 2 min, the reaction was terminated by adding 1.0 M HCl, and then the amount of PGE2 was measured by LC-MS/MS. Results are shown as mean±S.E.M. (*P<0.05 compared with control, n = 3, Student’s t-test).