Chenodeoxycholic acid

Dulbecco’s Modified Eagle Medium (DMEM), Roswell Park Memorial Institute 1640 medium (RPMI 1640) and penicillin/streptomycin (PS) were purchased from Gibco (USA). The standards included lithocholic acid, ursodeoxycholic acid, chenodeoxycholic acid, cholic acid, deoxycholic acid, glycolithocholic acid, glycoursodeoxycholic acid, glycodeoxycholic acid, glycocholic acid, taurolithocholic acid, glycochenodeoxycholic acid, tauroursodeoxycholic acid, taurochenodeoxycholic acid, taurodeoxycholic acid, taurocholic acid were purchased from Yuanye Bio-Technology Co., Ltd (Shanghai, China). Estradiol was obtained from Sigma (San Francisco, US), and Estradiol-3-O-sulfate was ordered from Meilun Bio-Technology Co., Ltd (Dalian, China). Naringenin was purchased from Yuanye Bio-Technology Co., Ltd (Shanghai, China). The purity of standards was always more than 98%. Methanol and acetonitrile were derived from Merck (Darmstadt, Germany). The deionized water (18 MΩ) was from a MilliQ water purification system (Millipore, Billerica, MA). HLB solid phase extraction column was sourced from Waters (Milford, MA, USA).