Polyhydroxytriterpenoids and Phenolic Constituents from Forsythia suspensa (Thunb.) Vahl Leaves

Forsythia suspensa (Thunb.) Vahl leaves have been consumed in China as a health-promoting functional tea for centuries. Three new polyhydroxytriterpenoid glycosides named suspensanosides A–C (<b>1</b>–<b>3</b>), seven known polyhydroxytriterpenoids (<b>4</b>–<b>10</b>), and 12 known phenolics (<b>11</b>–<b>22</b>) were identified from <i>F. suspensa</i> leaves. Compounds <b>1</b>–<b>10</b>, <b>15</b>–<b>17</b>, and <b>22</b> have not been found in the <i>Forsythia</i> genus previously, whereas compound <b>14</b> was first reported to be isolated from the leaves of <i>F. suspensa</i>. All isolates were tested for their antiproliferative activities on BGC-823 and MCF-7 human tumor cell lines, whereas all phenolics were further investigated for their antioxidant activities by a DPPH assay. The results clearly demonstrate that triterpenoids, especially ursane-type triterpenoids, and the diverse phenolic components are crucial for the beneficial effects of <i>F. suspensa</i> leaves