Patumantanes A-D, seco -Polycyclic Polyprenylated Acylphloroglucinols with Diverse Carbon Skeletons from Hypericum patulum .

Patumantanes A-D ( 1 - 4 ), four new seco -polycyclic polyprenylated acylphloroglucinols (PPAPs) were isolated from Hypericum patulum . Patumantane A ( 1 ) was an unprecedented 1,2- seco -homoadamantane-type PPAP bearing a new 3,7-dioxatetracyclo[7.7.0.0 1,6 .1 11,15 ]heptadecane architecture based on a 6/7/5/6 ring system. Patumantane B ( 2 ) was a unique 1,9- seco -adamantane-type PPAP with a tricyclo[4.4.4.0.0 2,12 ]tridecane core formed by a 6/6/6 carbon skeleton, and the further breakage between C-5 and C-9 decorated patumantane C ( 3 ) with the 9- nor -adamantane skeleton. More importantly, compounds 2 and 3 exhibited moderate immunosuppressive activity on Con A-induced T-lymphocyte proliferation in vitro , with IC 50 values of 5.6 ± 1.2 and 11.2 ± 1.2 μM, respectively.