Two New Spiro-Heterocyclic γ-Lactams from A Marine-Derived Aspergillus fumigatus Strain CUGBMF170049

Abstract

Two new spiro-heterocyclic γ-lactam derivatives, cephalimysins M (1) and N (2), were isolated from the fermentation cultures of the marine-derived fungus Aspergillus fumigatus CUGBMF17018. Two known analogues, pseurotin A (3) and FD-838 (4), as well as four previously reported helvolic acid derivatives, 16-O-propionyl-16-O-deacetylhelvolic acid (5), 6-O-propionyl-6-O-deacetylhelvolic acid (6), helvolic acid (7), and 1,2-dihydrohelvolic acid (8) were also identified. One-dimensional (1D), two-dimensional (2D) NMR, HRMS, and circular dichroism spectral analysis characterized the structures of the isolated compounds.

Marine Microbial Diversity as a Source of Bioactive Natural Products

“…Owing to the ease of isomerization of animals by successive ring-opening and ring-closing steps, it is expected that such compound would eventually generate the more stable stereoisomer, i.e., the cis ring junction isomer. Further, the 13 C NMR spectrum of compound 11 is similar enough to the one previously reported in the literature to conclude that the proposed structure was probably erroneous [17]. Compound 11 is in fact likely the (3aR,8aS)-1-acetyl-1,2,3,3a,8,8a-hexahydropyrrolo [2,3-b]indol-3a-ol rather than the (3aS,8aS) stereoisomer.…”

Genome-Inspired Chemical Exploration of Marine Fungus Aspergillus fumigatus MF071

“…They are produced by hybrid PKS/NRPS and other tailing enzymes, and exhibit a broad range of biological activities. However, the compounds showed no antibacterial activity in our screening at concentrations up to 100 μg/mL, which did not agree with the results of antibacterial activity against E. coli (ATCC 25922), P. aeruginosa (ATCC 27853), S. aureus (ATCC 25923) from Pinheiro et al [ 57 ] It is likely that different bacterial strains contributed to the different results, as pseurotin A was also reported to have no activity against S. aureus (ATCC 6538) and S. aureus [ 58 , 59 ]. The mechanism of the biosynthesis of the unusual spiro-ring structural feature of pseurotins has remained uncharacterized.…”

Classification of Aspergillus, Penicillium, Talaromyces and related genera (Eurotiales): An overview of families, genera, subgenera, sections, series and species

“…Extrolites in sect. Fumigati (with its eight families): ardeemins, asnovolins, aszonalenins, avenaciolides, cephalimycins, chaetominines, chevalones, chrysogines, clavatols, cycloechinulins, cyclopiazonic acids, cytochalasins, expansolides, fiscalins, fischerins, fumagillins,fumicyclins, fumigaclavines, fumigatins, fumigatonins, fumiquinazolines, fumitremorgins, gangicins, glabramycins, gliotoxins, helvolic acids, lentulins, neosartorins, novoamaauromins, novobenzomalvins, pseurotins, pyripyropenes, sartorypyrones, sphingofungins terreins trypacidins, tryprostatins, tryptoquivalines, viridicatumtoxins, viriditoxins, wortmannins and several more (see above) ( Hong et al., 2005 , Larsen et al., 2007 , Samson et al., 2007a , Hong et al., 2008 , Hubka et al., 2013b , Hubka et al., 2017 , Hubka et al., 2018a , Frisvad and Larsen, 2015 , Tamiya et al., 2015 , Bessa et al., 2016 , May Zin et al., 2016 , Rajachan et al., 2016 , Yu et al., 2016 , Bang et al., 2019 , Xu et al., 2019a , Yu et al., 2019 ). Among these, the aszonalenin biosynthetic family (BF) is shared by six species, the pyrones (aszonapyrone, chavalones, sartorypyrones) are shared by five species, the helvolic acid biosynthetic family is shared by five species, the pyripyropene BF is shared by four species, the gliotoxin BF is shared by four species, the fumigatin BF is shared by 4 species and the tryptoquivaline BF is shared by four species.…”