Discovery of immunosuppressive secondary metabolites from Hypericum patulum

The chemical study of Hypericum patulum provided a new degraded lupane-type triterpenoid, patutriter A (1), and seven known compounds (2-8). Their structures were identified by spectroscopic techniques and single crystal diffraction experiment. Structurally, patutriter A (1) was a new lupane with a 28-nor-skeleton. More importantly, compounds 3-5 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.