Chromogenic Triterpenoids fromCortinarius fulvoincarnatus,C. sodagnitus and Related Toadstools (Agaricales)

Abstract

Fruit‐bodies of the toadstools Cortinarius sodagnitus,C. fulvoincarnatus, C. arcuatorum(Agaricales) show a remarkable ink‐red colour reaction when treated with aqueous base. We isolated six chromogens, named the sodagnitins A–F, from the toadstools and elucidated their structures by spectroscopic techniques. The sodagnitins are triterpenoids of the malabaricane type with a highly modified side chain. A mechanism for the colour reaction is proposed.

Total Synthesis and Structural Revision of (−)‐Sodagnitin E

“…Although the synthetic material is in agreement with the reported data for the isolated material, we propose a revision of the relative configuration in the structure initially reported by Sontag et al., [ 4 ] As depicted in Figure 2, the configuration of C17 was not assigned in the isolation report. By synthesizing the natural product with a defined stereocenter at C17 and obtaining identical spectral data, we were able to assign C17 via synthesis.…”

“…After detailed NOE‐analysis (nuclear Overhauser effect), we additionally propose a structural revision of the anomeric center at C27. Notably, this does not contradict the NOE observations reported by Sontag et al, [ 4 ] as detailed in the Supporting Information. The synthesized product exhibits negative optical rotation, but due to the absence of literature values, the absolute configuration of natural sodagnitin E ( 2 ) remains undetermined.…”

Phylogenetic relationships in Cortinarius, section Calochroi, inferred from nuclear DNA sequences

“…Numbers above nodes are ML bootstrap values, numbers below nodes are MP bootstrap values (values < 50% not shown) from 1000 replicates, respectively. Distributions of basidiome pigments were retrieved from [ 7 , 9 , 10 , 64 ] and are abbreviated as follows. Flavomannin pigments: ATR = atrovirin, FDM = flavomannin-6-6'dimethylether, 4-OH-FDM = 4-OH-flavomannin-6,6'-dimethylether, FLA = flavomannin, FTM = flavomannin-6,6',8-trimethylether; phlegmacin pigments: LRU = leucorufoolivacins, PHL = phlegmacin, PME B 2 = phlegmacin-8'-methylether B 2 ; triterpenoid pigments: S = sodagnitins A-F.…”

“…Members of the Dibaphi clade share similar colour changes with KOH, pigment content and colour patterns of the basidiomes. Chromogenic triterpenoid pigments (sodagnitins) in C. arcuatorum [ 10 ] and probably in other Dibaphi may be significant chemical markers for this group. Sequences of New World populations of C. arcuatorum differ significantly from their European counterparts, and they cluster into three closely related monophyletic groups, which roughly correspond to their respective geographical ranges of distribution.…”

Pigments of fungi (Macromycetes)

“…4 Unfortunately, the literature citation in that review is incorrect, it should be that quoted as ref. 78 herein.…”