Chemical structure and stability of apigenin.

<p>(<b>A</b>) 4′, 5, 7-trihydroxyflavone (<b>B</b>) Apigenin stability was determined at 37°C by incubating 20 µM apigenin with or without human prostate cancer PC-3 cells for up to 96 h. The concentration of apigenin at each time point was measured using UV-HPLC. Points±SD, percentage of remaining apigenin performed three times. Details are described in materials and methods section.