Six New Antimicrobial Metabolites from the Deep-Sea Sediment-Derived Fungus Aspergillus fumigatus SD-406

Abstract

Six new metabolites, including a pair of inseparable mixtures of secofumitremorgins A (1a) and B (1b), which differed in the configuration of the nitrogen atom, 29-hydroxyfumiquinazoline C (6), 10R-15-methylpseurotin A (7), 1,4,23-trihydroxy-hopane-22,30-diol (10), and sphingofungin I (11), together with six known compounds (2–5 and 8–9), were isolated and identified from the deep-sea sediment-derived fungus Aspergillus fumigatus SD-406. Their structures were determined by detailed spectroscopic analysis of NMR and MS data, chiral HPLC analysis of the acidic hydrolysate, X-ray crystallographic analysis, J-based configuration analysis, and quantum chemical calculations of ECD, OR, and NMR (with DP4+ probability analysis). Among the compounds, 1a/1b represent a pair of novel scaffolds derived from indole diketopiperazine by cleavage of the amide bond following aromatization to give a pyridine ring. Compounds 1, 4, 6, 7, 10 and 11 showed inhibitory activities against pathogenic bacteria and plant pathogenic fungus, with MIC values ranging from 4 to 64 μg/mL.

Marine natural products

“…N -Methylated cyclic peptides, asperflomide 312 and asperflosamide 313 were isolated from A. flocculosus 140 and A. fumigatus strains were the source of a steroid 314 , a 2-oxofuranone derivative 315 , indole alkaloids 316 and 317 (as an inseparable mixture), 318 , pseurotin A derivative 319 , 141 alkaloids 320 – 324 , and penibenzophenone E 325 . 142 Gorgonian-derived Aspergillus hiratsukae strains yielded α-pyrone meroterpenoids 326 – 331 , 143 cyclic peptide 332 , ecdysteroid derivative 333 and sesquiterpene lactone 334 , 144 and nitrobenzoyl sesquiterpenoids 335 – 338 , 145 cyclohexadepsipeptides 339 , 340 (ref.…”

Marine Aspergillus: A Treasure Trove of Antimicrobial Compounds

“…(88) and sphingofungin I (89), and one known cyclotryprostatin B (90). Compounds 85-90 exhibited inhibitory activities against pathogenic bacteria and plant pathogenic fungi, with MIC values of 4-64 μg/mL [76].…”

Antibacterial Indole Diketopiperazine Alkaloids from the Deep-Sea Cold Seep-Derived Fungus Aspergillus chevalieri

“…and cephalosporin C derived from Acremonium chrysogenum . Therefore, much attention has been paid to fungal secondary metabolites with potent antibacterial activities and novel mechanisms [ 1 , 2 , 3 ]. Deep-sea cold seeps are special extreme environments characterized by fluid emissions rich in methane and hydrogen sulfide, developing a unique chemosynthetically-driven ecosystem that creates a unique habitat for microorganisms in sediments [ 4 ].…”