Antifungal Polyketides and Other Compounds from Amazonian Endophytic Talaromyces Fungi

Abstract

The continuous search for biologically active compound candidates pushes the pursuit of new substances produced by diverse organisms. Endophytic fungi are known as a promising source of metabolites with several biological activities. Based on the rich Amazonian biodiversity and the chemical potential of microbial sources, three Talaromyces strains, all major endophytes from their respective host plants, were studied aiming at the isolation of biologically active secondary metabolites. Through classical chromatographic approaches, 13 compounds were isolated from the antimicrobial extracts of the studied strains. From these, polyketides, steroids, anhydrides, and phenolic compounds were identified. Among them, two previously undescribed compounds were elucidated based on spectroscopic and spectrometric methods, a homodimer chromanone and a maleic anhydride methyl ester. The antimicrobial activity against a panel of pathogenic microorganisms from extracts, fractions, and isolated compounds was evaluated.

Chromanone Lactones: A Neglected Group of Natural Products – Isolation, Structure Elucidation, Bioactivity, and Synthesis

“…As expected for the prepared compound 162, and in contrast to the NMR spectra of paecilin A it contains only one [20,22,58] Scheme 20. Synthesis of a homo-dimeric chromanone lactone by Tietze et al [42] set of signals for the monomeric moieties also indicating that there is a free rotation about the 8-8' axis.…”

“…In a publication of 2018 by da Silva et al, the isolation of versixanthone A from Talaromyces stipitatus DgCr2 2.1b was also reported. [22] With versixanthones C and D (205 and 206) two more mixed chromanone lactone dimers of the versixanthone type with a 2-8' and a 2-6' connection were described. Both compounds show a free rotation about the biphenyl axis at room temperature.…”

Changes in Bacterial Endophyte Community Following Aspergillus flavus Infection in Resistant and Susceptible Maize Kernels

“…In addition to polyketides derived from endophytic bacteria, polyketides produced by endophytic fungi have also demonstrated antimicrobial activities against fungal pathogens. Extracts from Amazonian plant endophytic fungal strains of Talaromyces identified antimicrobial compounds such as polyketides, steroids, anhydrides, and phenolics [ 35 ]. In vitro antimicrobial evaluation of these compounds demonstrated the antifungal properties of specific polyketides.…”

Biotransformation ability of endophytic fungi: from species evolution to industrial applications

“…MK629267 Asperfuranoids A Cai et al ( 2019 ) 88 Asperfuranoids B 89 Asperfuranoids C 90 Asperpanoid A 91 Asperpanoid B 92 Lemna gibba Streptomyces sp . MF347418 8-Hydroxy-3,4-dihydro-1 H -quinolin-2-one Antibacterial and cytotoxic activity Mahmoud et al ( 2018 ) 93 3,4-Dihydro-1 H -quinolin-2-one 94 8-Methoxy-3,4-dihydro-1 H -quinolin-2-one 95 Pulicaria crispa Aspergillus versicolor Aspernolides L Antibacterial, antifungal, cytotoxic and antimalarial activities Ibrahim et al ( 2018 ) 96 Aspernolides M 97 Casearia sylvestris Colletotrichum crassipes CSY-03 1-Phenylethyl- O -α- L -rhamnopyranoside Inhibition effect of acetylcholine- sterase Chapla et al ( 2018 ) 98 Duguetia stelechantha Talaromyces stipitatus DgCr2 2.1b Paecillin D Antibacterial activity da Silva et al ( 2017 ) 99 Nicotiana tabacum Rhizopycnis vagum Nitaf 22 Rhizopycnolide A Lai et al ( ...…”