Immunosuppressive sesquiterpenes from Tripterygium wilfordii

Five new sesquiterpenes, 1 beta-furanoyl-2 beta,3 alpha,7 alpha,8 beta-pentaacetoxy-4 alpha,5 alpha-dihydroxy-dihydroagarofuran (1), 1 beta,2 beta,3 alpha,5 alpha,7 beta,8 beta,11-heptaacetoxy-dihydroagarofuran (2), 1 beta-furanoyl-2 beta,3 alpha 7 alpha,8 beta,11-pentaacetoxy-5 alpha hydroxy-dihydroagarofuran (3), l beta,7 beta,8 alpha-triacetoxy-2 beta-furanoyl-4 alpha-hydroxy-11-isobutyryloxy-dihydroagarofuran (4), and 1 beta-nicotinoyl-2 beta,5 alpha,7 beta-triacetoxy-4 alpha-hydroxy-11-isobutyryloxy-8 alpha-furanoyl-dihydroagarofuran (5), were isolated from the xylem of Tripterygium wilfordii, together with a known compound (6). Their structures were elucidated on the basis of spectroscopic studies. Compounds 2-5 showed significant immunosuppressive activities.