Immunosuppressive ent-Kaurene diterpenoids from Isodon serra

Abstract

Three new enmein-type ent-kaurenoids, i.e., the two pairs 1 and 2 of 20-epimers and the (20R)-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 (Table3).