Structurally diverse lanostane triterpenoids from medicinal and edible mushroom Ganoderma resinaceum Boud.

Abstract

Ganoderma resinaceum is a multi-purpose herbal medicine that is homologous to functional food that has long been used for enhancing health and treating chronic hepatopathy in Traditional Chinese Medicine. In a search program to discover the key bioactive composition of G. resinaceum, sixteen new lanostane-type triterpenoids (1-16), and twenty known analogues (17-36) were isolated from the fruiting bodies of G. resinaceum. Spectroscopic analyses and X-ray crystallography were used to determine the new structures. Furthermore, the spectroscopic properties of 15β-hydroxy-4,4,14α- trimethyl-3,7,11,20-tetraoxo-5α-pregn-8-ene (15) and 15α-hydroxy-4,4,14α-trimethyl- 3,7,11,20-tetraoxo-5α-pregn-8-ene (34) indicated a potential structural misassignment of their analogues, lucidone E and lucidone H, reported previously. To probe this hypothesis, ROESY experiments and single-crystal X-ray diffraction analysis were conducted. These results undoubtedly reassigned the structure of lucidone E and lucidone H. Biological evaluation of the selected compounds disclosed that compounds 3, 4, 7/21, 11, 12, 13/14, 17, 18, 24/25, 27, 30, 31, and 35 had significant hepatoprotective activities, due to their remarkable in vitro inhibitory activities against the increase of ALT and AST levels in HepG2 cells induced by H2O2.