Unprecedented Immunosuppressive Polyketides from Daldinia eschscholzii, a Mantis‐Associated Fungus

Abstract

Going with a gut reaction: Dalesconols A (structure shown) and B were discovered in the title fungus (middle picture) derived from the mantis gut. The novel architecture and biological profiles of these natural products make the dalesconols attractive lead compounds for the development of immunosuppressive agents.

Naphthol radical couplings determine structural features and enantiomeric excess of dalesconols in Daldinia eschscholzii

“…Furthermore, the investigation foretells as well that the laccase-catalyzed radical coupling among different starting phenols to form useful natural products of high complexity may be quite common. Our data update the existing views regarding the C-C bond formation via phenoxy radical couplings, and renewed knowledge about the construction logic of hydroxylnaphthalene starters produced by a broad taxonomic range of microbes [4][5][6]9,15,29,30 , which is overall of general importance in manipulating the microbial production and/or chemical synthesis of the immunosuppressants dalesconols A and B as well as other structurally related compounds of industrial potentials.…”

“…This assumption was substantiated by the fact that the fungus produced as well naphthol-dimerized derivatives such as dihydrosphaerolone and 2,16-dihydroxyl-benzo[j]fluoranthene (a new potent immunosuppressor) 5,6 . To confirm this prediction, we searched for the genetic evidence to lead to the identification of pksTL, a gene encoding 1,3,6,8-tetrahydroxynaphthalene synthase (4HNS).…”

“…The electrospray ionization interface was operated in negative mode with the source temperature at 350 °C, curtain gas flowed at 20 l min − 1 , and IonSpray voltage at − 4500 V. The multiple reaction monitoring channels were monitored in windows covering the eluted compounds of interest (parent > daughter): electrospray ionization interface negative, dwell time 50 ms. Specifically, dalesconol A (1) All authentic samples used for the purpose were isolated in Tan's lab as described 5,6 . The filtrate of the fermented cultures was extracted exhaustively with ethyl acetate.…”

Considerations of the chemical biology of microbial natural products provide an effective drug discovery strategy

“…In 2008, Tan and coworkers isolated the fungus Daldinia eschscholzii strain from the gut of the mantis Tenodera aridifolia; a predator of many insects feeding on endophyte-bearing plants (Zhang et al 2008). Chemical investigations of culture extracts of this fungus resulted in the discovery of dalesconols A (8) and B, which possessed an unprecedented carbon framework (Zhang et al 2008).…”

Isolation of Bioactive Metabolites Producing Fungal Strains From Milk Products and Milk Industries of Raipur District

“…[6] Daldinia eschscholzii, isolated from the gut of the mantis species Tenodera aridifolia, was reported to simultaneously generate four novel skeletons and seven structurally unique metabolites that have the potential to become immune inhibitors. [7,8] [11]…”