Discovery of immunosuppressive secondary metabolites from <i>Hypericum patulum</i>

The chemical study of <i>Hypericum patulum</i> provided a new degraded lupane-type triterpenoid, patutriter A (<b>1</b>), and seven known compounds (<b>2</b>-<b>8</b>). Their structures were identified by spectroscopic techniques and single crystal diffraction experiment. Structurally, patutriter A (<b>1</b>) was a new lupane with a 28-<i>nor</i>-skeleton. More importantly, compounds <b>3</b>-<b>5</b> exhibited moderate immunosuppressive effects that inhibit the anti-CD3/anti-CD28 monoclonal antibodies (mAbs) and concanavalin A (ConA) stimulated murine splenocytes proliferation, with IC₅₀ values from (15.25 ± 1.78) μM to (22.58 ± 3.47) μM, disclosing that those compounds might serve as potential lead compounds in the development of new immunosuppressants.