Immunosuppressive ent ‐Kaurene Diterpenoids from Isodon serra

Three new enmein‐type ent ‐kaurenoids, i.e. , the two pairs 1 and 2 of 20‐epimers and the (20 R )‐isomer 3 , besides the seven known diterpenoids 4 – 10 , were isolated from the aerial parts of Isodon serra. Their structures were elucidated by spectroscopic techniques and X‐ray diffraction. The immunosuppressive effect for T‐lymphocytes proliferation induced by Con A in BALB/c mouse was evaluated for the isolates 1 – 10 . They all displayed a remarkable inhibitory effect, with multi‐glycosides of Tripterygium wilfordii as positive reference substance ( Table 3 ).