6/6/5-membered ring system has also been isolated. Considering the structural
relationship among 128, 129, and 116, 116 might be a biosynthetic intermediate of
128 and 129.
8 Pentacarbocyclic Sesterterpenoids
Pentacarbocyclic sesterterpenoids are rare, and the complexity of their structures is
quite high. In particular, the type 1 terpene cyclases are known to generate fascinating pentacarbocyclic skeletons.
8.1 Pentacarbocyclic Sesterterpenoids Constructed by
the Type 1 Terpene Cyclases
8.1.1 5/6/5/6/5-Membered Ring System
Peniroquesine A (130) and its derivatives, which possess 5/6/5/6/5-membered ring
systems, have been isolated from the fungus Penicillium roqueforti YJ-14 (Fig. 94)
[117]. Compound 130 is a potent inhibitor of nitric oxide production in
OPP
8
H
H
HO
OH
130
Fig. 94 Structure of peniroquesine A (130), and possible cyclization reaction for the formation of
the 5/6/5/6/5-membered ring system
Sesterterpenoids
51
relationship among 128, 129, and 116, 116 might be a biosynthetic intermediate of
128 and 129.
8 Pentacarbocyclic Sesterterpenoids
Pentacarbocyclic sesterterpenoids are rare, and the complexity of their structures is
quite high. In particular, the type 1 terpene cyclases are known to generate fascinating pentacarbocyclic skeletons.
8.1 Pentacarbocyclic Sesterterpenoids Constructed by
the Type 1 Terpene Cyclases
8.1.1 5/6/5/6/5-Membered Ring System
Peniroquesine A (130) and its derivatives, which possess 5/6/5/6/5-membered ring
systems, have been isolated from the fungus Penicillium roqueforti YJ-14 (Fig. 94)
[117]. Compound 130 is a potent inhibitor of nitric oxide production in
OPP
8
H
H
HO
OH
130
Fig. 94 Structure of peniroquesine A (130), and possible cyclization reaction for the formation of
the 5/6/5/6/5-membered ring system
Sesterterpenoids
51