Antiproliferative Prenylated Xanthones and Benzophenones from the Roots of <i>Cudrania tricuspidata</i> in HSC-T6 Cells

Four new prenylated xanthones, cudracuspixanthones A–D (<b>1</b>–<b>4</b>), two new prenylated benzophenones, cudracuspiphenones A (<b>5</b>) and B (<b>6</b>), and 11 known xanthones (<b>7</b>–<b>17</b>) were isolated from the roots of <i>Cudrania tricuspidata</i>. The absolute configurations of compounds <b>2</b>–<b>4</b> were deduced by the comparison of the calculated optical rotation values with the measured data. Compounds <b>1</b>, <b>5</b>, and <b>6</b> showed moderate antiproliferative activity on HSC-T6 cells with IC₅₀ values of 9.7, 3.3, and 7.1 μM, respectively. Compounds <b>2</b>–<b>4</b>, <b>10</b>, and <b>14</b>–<b>16</b> had weaker activity. Flow cytometric analysis suggested that compounds <b>1</b> and <b>5</b> inhibited HSC-T6 cell proliferation in part by inducing apoptosis