3.5. Fusicoccane
In recent years, Zhang’s group has reported a serious of fusicoccane
diterpenoids with unexpected carbon skeleton from the genusAlternaria and Talaromyces . Alterbrassicene A
(97 ),[118] a fusicoccane diterpenoid
bearing an unprecedented 5/9/4-fused carbocyclic skeleton, has been
characterized from Alternaria brassicicola . 97 is the
first fusicoccane derivative acting as a potent IKKβ inhibitor in
the NF-κ B signaling pathway. Alterbrassicicene A
(98 ),[119] a fusicoccane diterpenoid with
a degradatived framework, has been also obtained from A.
brassicicola . 98 reprents the first fusicoccane-derived
diterpenoid functioning as a potent PPAR-γ agonist
(EC50 = 744.1 nM). A plausible biosynthetic pathway for98 has been proposed and involved in a series of cyclizations
and rearrangement by the function of enzymes (Fig. 15). Alterbrassinoids
A−D (99 −102 ),[120] the first
examples of fusicoccane dimers furnished by forming an undescribed
C-12−C-18′ bond, have been isolated from the same fungus. Talaronoids
A–D (103 −106 ), four diterpenoids with an unexpected
tricyclic 5/8/6 carbon skeleton, have been isolated fromTalaromyces stipitatus . Talaromynoid A
(107 ),[121] the first fusicoccane
diterpenoid bearing an unexpected 5/7/5 tricyclic ring system, have been
obtained from the endophytic fungus Talaromyces sp. DC-26.
Fig. 15. Proposed biosynthetic pathway for 98 .