Lanostane-type triterpenoids from the mycelial mat of Ganoderma lucidum and their hepatoprotective activities.

Ganoderma lucidum (G. lucidum), a well-known Polyporaceae family fungus, is valued for its edibility and medicinal properties. It is a rich source of active polysaccharides and triterpenoids. However, obtaining material for medicinal purposes relies on artificial cultivation in a greenhouse, which requires large amounts of tree trunk due to the low biomass transformation rate. Therefore, an effective and environment-friendly culture method should be developed and the chemical compounds in the cultured material should be studied. Here we report the isolation and structural elucidation of 10 undescribed lanostane triterpenoids and 21 known compounds from statically cultured mycelial mat of G. lucidum. The hepatoprotective activity of these compounds in H2O2-induced HepG2 cells was evaluated. The structure-activity relationship is discussed. Our results demonstrated that twelve ganoderic acid derivatives possess significant hepatoprotective activities, as judged by suppressed activities of ALT, AST and LDH and increased GSH levels in H2O2-injured HepG2 cells.

Manipulations of phenylnorbornyl palladium species for multicomponent construction of a bridged polycyclic privileged scaffold.

Hexahydromethanocarbazole is a privileged scaffold in the discovery of new drugs and photoactive organic materials due to its good balance between structural complexity and minimized entropy penalty upon receptor binding. To address the difficulty of synthesizing this highly desirable bridged polycyclic scaffold, we designed a convenient multicomponent reaction cascade as intercepted Heck addition/C-H activation/C-palladacycle formation/electrophilic attack of ANP/N-palladacycle formation/Buchwald amination. A distinguishing feature of this sophisticated strategy is the successive generation of two key phenylnorbornyl palladium species to control the reaction flow towards desired products. DFT calculations further reveal the crucial roles of Cs2CO3 and 5,6-diester substitutions on the norbornene reactant in preventing multiple side-reactions. This innovative method exhibits a broad scope with good yields, and therefore will enable the construction of natural-product-like compound libraries based on hexahydromethanocarbazole.