Methanol of hplc grade

Silybin coarse powder (purity: 98.0%) was provided by Panjin Huacheng Pharmaceutical Co., Ltd. (Panjin, China). The reference substance of silybin (purity >99%) was purchased from National Institute for the Control of Pharmaceutical and Biological Products (Beijing, China). Soybean phospholipid with the phosphatidylcholine (PC) content of approximately 98% was supplied by Shanghai Tai-Wei Pharmaceutical Co. Ltd. (Shanghai, China). Labrasol and transcutol HP were gifts from GATTEFOSSE (Saint-Priest, France). Cremophor RH40 was a gift from BASF (Ludwigshafen, Germany). Dulbecco's modified Eagle medium (DMEM, high glucose), non-essential amino acids, fetal bovine serum, and Hank's buffered salt solution (HBSS) were bought from Gibco Company (Carlsbad, CA). Methanol of HPLC grade was obtained from TEDIA Company, Inc. (Fairfield, CT). Water was purified by using a Milli-Q water purification system (Millipore, Bedford, MA). All other reagents and chemicals used in this study were of analytical grade or better.

Luteolin (purity > 98%, batch number: XC071225) was purchased from Xi'an Xiaocao Botanical Development Co., Ltd. (Xi'an, China). Sodium carboxymethyl cellulose (CMC-Na), prednisone, prednisolone, and dexamethasone (internal standard for HPLC analysis) were purchased from Sigma-Aldrich Corporation (St. Louis, MO, USA). Methanol of HPLC grade was purchased from TEDIA Company Inc. (Beijing, China). The following items were purchased from the cited commercial sources: anti-11β-HSDI (Abcam, Cambridge, UK, dilution 1 : 800), anti-11β-HSD II (Abcam, Cambridge, UK, dilution 1 : 1000), GAPDH (Santa Cruz Biotechnology Inc., Santa Cruz, CA, USA, dilution 1 : 500) antibodies, goat anti-rabbit IgG (HþL) HRP (BS13278), GAPDH (AP0063), and goat anti-mouse IgG (HþL) HRP (BS12478). All other reagents were of analytical grade.