Apigetrin

The human normal prostate cell line RWPE-1 cells were purchased from American Type Culture Collection (ATCC, Manassas, VA, USA) and cultured in the keratinocyte serum free media kit (K-SFM kit, Invitrogen-GIBCO, Carlsbad, CA, USA) at 37 °C with 5% CO₂. The human PCa cell lines LNCaP and PC-3 were obtained from the Korean cell line bank (KCLB, Seoul, Korea) and cultured in the RPMI-1640 medium with 10% fetal bovine serum and 1% penicillin/streptomycin (WelGene, Daegu, Korea) at 37 °C with 5% CO₂. HUVECs were cultured in M199 medium with 20% fetal bovine serum, 5 U/mL heparin, 3ng/mL basic fibroblast growth factor (R&D Systems, Minneapolis, MN, USA), and 100 U/mL of antibiotic–antimycotic in 0.1% gelatin-coated flasks at 37 °C with 5% CO₂. Apigetrin (Sigma-Aldrich, St. Louis, MO, USA) was dissolved in Dimethyl Sulfoxide (DMSO) and used for in vitro assays and mechanistic studies.

Solvents for UHPLC/MS analysis (acetonitrile and formic acid) were of MS grade, obtained from Fisher Scientific (Loughborough, UK). Ultrapure water was generated by deionization (Millipore, Billerica, MA, USA). Standards of phenolic acids and flavonoids (caffeic acid, aesculin, chlorogenic acid, p-coumaric acid, ferulic acid, rutin, cynaroside, apigetrin, luteolin, and apigenin) were purchased from Sigma-Aldrich (Steinheim, Germany).