Discovery of immunosuppressive Lupane-type Triterpenoids from Hypericum longistylum

The phytochemistry study of Hypericum longistylum afforded one new degraded lupane-type triterpenoid, triterhyper A (1), and seven known congeners (2-8). The structures of those natural products were identified by extensive spectroscopic techniques and single crystal diffraction tests. Notably, triterhyper A (1) possessing an unusual 28-nor-lupane skeleton. More significantly, compounds 1-3 exhibited potential inhibitory effects on murine splenocytes proliferation stimulated by anti-CD3/anti-CD28 monoclonal antibodies (mAbs) and lipopolysaccharide (LPS), with IC₅₀ values ranging from (4.56 ± 0.45) μM to (18.34 ± 2.34) μM, highlighting that those isolates as potential lead compounds in the development of immunosuppressive drugs for autoimmune disease treatment.