Illudane Sesquiterpenoids from Edible Mushroom Agrocybe salicacola and Their Bioactivities

Abstract

To comprehensively understand the chemical constituents of the edible mushroom Agrocybe salicacola and their biological functions, a phytochemical separation of the cultural broth of A. salicacola led to the isolation of four new illudane sesquiterpenoids, agrocybins H–K ( 1 – 4 ), along with 10 known analogues ( 5 – 14 ). Compounds 2 – 4 were racemates of which 2 and 3 were further separated into single enantiomers as 2a / 2b and 3a / 3b . All new structures with absolute configurations were elucidated on the basis of an extensive spectroscopic analysis and quantum chemistry calculations. Compound 1 possesses a new carbon skeleton that might be derived from the protoilludane backbone. Compounds 1 , 5 , 8 , and 9 show a certain degree of cytotoxicity to five human cancer cell lines. Compound 1 shows a mild inhibitory effect on nitric oxide production with an IC 50 value of 31.4 μM. It is concluded that A. salicacola is rich in illudin derivatives with potential bioactivity prospects, which would make A. salicacola a good material of medicine and food homology.

A comprehensive review of secondary metabolites from the genus Agrocybe : Biological activities and pharmacological implications

“…Compound 40 had moderate activity against B. subtilis , Escherichia coli , and S. aureus , and also showed certain cytotoxicity (Reina et al 2004 ). Dai et al ( 2020 ) successfully isolated 13 illudin derivatives from the cultural broth of A. salicacola , including agrocybins H–K ( 41–44 ) and nine analogues, dihydrogranuloinden ( 45 ), echinolactone D ( 46 ), (2 S ,3 S ,9 R )-14-hydroxy-5-desoxy-illudosin ( 47 ), sterostrein O ( 48 ), agrocybins D–G ( 34–37 ), and (2 R )-2,3-dihydro-7-hydroxy-2-(hydroxymethyl)-2,4,6-trimethyl-1 H-indene-5-ethanol ( 49 ) ( Figure 5 ). Structurally, the carbon skeleton of compound 41 has never been described and was probably derived from the protoilludane skeleton by carbon-carbon bond breaking, and compounds agrocybins I–K ( 42–44 ) were aromatised illudin racemates, which were further isolated to give single enantiomers 42 R / S and 43 R / S .…”

Sesquiterpenoids Specially Produced by Fungi: Structures, Biological Activities, Chemical and Biosynthesis (2015–2020)

“…Phellinuin J 177 and sulphureuine A 178 were isolated from cultures of Phellinus tuberculosus and Laetiporus sulphureus [80]. Agrocybins H-K 179-184 were obtained from the edible mushroom Agrocybe salicacola [81]. Craterellins D 185 and E 186 were isolated from cultures of Craterellus cornucopioides [82].…”