Bioactive Indole Diketopiperazine Alkaloids from the Marine Endophytic Fungus Aspergillus sp. YJ191021

Abstract

Six new prenylated indole diketopiperazine alkaloids, asperthrins A–F (1–6), along with eight known analogues (7–14), were isolated from the marine-derived endophytic fungus Aspergillus sp. YJ191021. Their planar structures and absolute configurations were elucidated by HR-ESI-MS, 1D/2D NMR data, and time-dependent density functional theory (TDDFT)/ECD calculation. The isolated compounds were assayed for their inhibition against three agricultural pathogenic fungi, four fish pathogenic bacteria, and two agricultural pathogenic bacteria. Compound 1 exhibited moderate antifungal and antibacterial activities against Vibrioanguillarum, Xanthomonas oryzae pv. Oryzicola, and Rhizoctoniasolani with minimal inhibitory concentration (MIC) values of 8, 12.5, and 25 μg/mL, respectively. Furthermore, 1 displayed notable anti-inflammatory activity with IC50 value of 1.46 ± 0.21 μM in Propionibacteriumacnes induced human monocyte cell line (THP-1).

Marine-Derived Indole Alkaloids and Their Biological and Pharmacological Activities

“…Compound 46 features an angularly fused pyranoindole containing a diketopiperazine-fused amine pyrrole ring system. The planar structures of 41-46 were established by extensive analysis of 1D and 2D NMR spectra while the absolute configurations of their stereogenic carbons were determined by comparison of the calculated and experimental ECD spectra [22].…”

“…Oryzicola, E. tarda, V. anguillarum, V. parahaemolyticus, and A. hydrophilia = 12.5, 12.5, 2, 0.5, 2 and 2 µg/mL, respectively). On the other hand, asperthin E (45) only showed weak antifungal activity against R. solani with a MIC value of 25 µg/mL (MIC of a positive control, ketoconazole = 0.78 25 µg/mL) [22].…”

Natural Indole Alkaloids from Marine Fungi: Chemical Diversity and Biological Activities

“…Asperthrin A ( 30 ) showed moderate inhibitory activities against three agricultural pathogenic microorganisms and significant antiinflammatory effect with IC 50 value of 1.46 ± 0.21 μmol/L in the model of human monocyte cell line (THP-1) induced by Propionibacterium acnes . 32…”

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“…Notoamide G (8) inhibited the viability of HepG2 and Huh-7 cells via apoptosis and autophagy way through a P38/JNK signaling pathway. 31 Six new prenylated indole alkaloids with diketopiperazine ring, asperthrins A-F (30)(31)(32)(33)(34)(35), were obtained from marine fungi Aspergillus sp. YJ191021 (►Fig.…”

“…Asperthrin A (30) showed moderate inhibitory activities against three agricultural pathogenic microorganisms and significant antiinflammatory effect with IC 50 value of 1.46 AE 0.21 μmol/L in the model of human monocyte cell line (THP-1) induced by Propionibacterium acnes. 32 Paraherquamide J (36) (►Fig. 3) is a new prenylated indole alkaloid, obtained from the fungus Penicillium janthinellum HK1-6, which was derived from mangrove rhizosphere soil.…”