Effects of flavonoids isolated from licorice roots (Glycyrrhiza inflata Bat.) On degranulation in human polymorphonuclear neutrophils

The effects of chalcones and flavanone isolated from licorice roots ( Glycyrrhiza inflata Bat.) on human polymorphonuclear neutrophil (PMN) degranulation were investigated. Licochalcone A (2‐methoxy‐4,4′‐dihydroxy‐5‐α,α‐dimethylallylchalcone) and licochalcone B (2‐methoxy 3,4,4′‐trihydroxychalcone), at concentrations of 10 −6 M to 10 −3 M, inhibited calcium ionophore A 23187 (A 23187)‐, leukotriene B 4 (LTB 4 ) plus cytochalasin B (cyto B)‐, platelet activating factor (PAF) plus cyto B‐ and N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) plus cyto B‐induced lysosomal enzyme release from human PMNs. Isoliquiritigenin, isoliquiritin, liquiritigenin and liquiritin had no effects on PMN degranulation induced by various stimuli. In addition, licochalcones A and B, at high concentrations (10 −4 M–10 −3 M), increased cyclic AMP in human PMNs. Furthermore, licochalcones A and B, at concentrations of 10 −6 M to 10 −3 M, reduced the elevation of cytosolic free calcium concentration induced by calcium ionophore ionomycine (ionomycine), fMLP, PAF and LTB 4 .