Liquiritigenin

Liquiritigenin, a flavanone isolated from Glycyrrhiza uralensis, is a highly selective estrogen receptor β (ERβ) agonist with an EC₅₀ of 36.5 nM for activation of the ERE tk-Luc. IC50 & Target: EC50: 36.5 nM (activation of the ERE tk-Luc)^[1] In Vitro: Liquiritigenin produces a dose-response activation of ERE tk-Luc in the U2OS cells transfected with ERβ, but not ERα. Liquiritigenin produces a dose-dependent activation and a time-dependent increase of the CECR6, NKG2E and NKD with ERβ but not with ERα. The ERβ-selectivity of liquiritigenin is due to the selective recruitment of the coactivator steroid receptor coactivator-2 to target genes. Liquiritigenin exhibits similar binding affinities for ERα and ERβ, and causes the recruitment of SRC-2 to target genes selectively in ERβ cells^[1]. Pretreatment of MC3T3-E1 cells with liquiritigenin prevents the MG-induced cell death and production of protein adduct, intracellular reactive oxygen species, mitochondrial superoxide, cardiolipin peroxidation, and TNF-α in osteoblastic MC3T3-E1 cells^[2]. In Vivo: In a mouse xenograph model, liquiritigenin does not stimulate uterine size or tumorigenesis of MCF-7 breast cancer cells^[1]. Treatment with liquiritigenin significantly reduces the concentrations of pro-inflammatory cytokines including interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α in serum and hippocampus^[3].