(±)-Talapyrones A-F (1-6), six pairs of dimeric polyketide enantiomers featuring unusual 6/6/6 and 6/6/6/5 ring systems, were isolated from the fungus Talaromyces adpressus. Their structures were determined by spectroscopic analysis and HR-ESI-MS data, and their absolute configurations were elucidated using a modified Mosher's method and electronic circular dichroism (ECD) calculations. (±)-Talapyrones A-F (1-6) possess a 6/6/6 tricyclic skeleton, presumably formed through a Michael addition reaction between one molecule of α-pyrone derivative and one molecule of C₈ poly-β-keto chain. In addition, compounds 2/3 and 4/5 are two pairs of C-18 epimers, respectively. Putative biosynthetic pathways of 1-6 were discussed.
Polyketides/isolation & purification* ; Talaromyces/chemistry* ; Stereoisomerism ; Molecular Structure ; Circular Dichroism ; Pyrones/chemistry*

To isolate and identify secondary metabolites of marine-derived Streptomyces sp.MDW-06,the isolations and purifications of compounds were performed by means of column chromatography over silica gel. And their structures were elucidated through the spectroscopic analysis of MS,NMR and specific rotations. The bioactivities were assayed by paper diffusion and DPPH method. From the fermentation broth of marine-derived Streptomyces sp.MDW-06,five compounds( 1-5) were isolated and identified as streptopentanoic acid( 1),germicidin A( 2),germicidin B( 3),isogermicidin A( 4),isogermicidin B( 5) and oxohygrolidin( 6),respectively. Compound 1 is a new compound. Compound 1 shows DPPH radical scavenging activity with 36. 4% at 100 mg·L~(-1).
Chromatography ; Fermentation ; Free Radical Scavengers ; chemistry ; isolation & purification ; Magnetic Resonance Spectroscopy ; Polyketides ; chemistry ; isolation & purification ; Streptomyces ; chemistry

Two new isomeric modified tripeptides, aspergillamides C and D (compounds 1 and 2), together with fifteen known compounds (compounds 3-17), were obtained from the marine sponge-derived fungus Aspergillus terreus SCSIO 41008. The structures of the new compounds, including absolute configurations, were determined by extensive analyses of spectroscopic data (NMR, MS, UV, and IR) and comparisons between the calculated and experimental electronic circular dichroism (ECD) spectra. Butyrolactone I (compound 11) exhibited strong inhibitory effects against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with the IC being 5.11 ± 0.53 μmol·L, and acted as a noncompetitive inhibitor based on kinetic analysis.
4-Butyrolactone ; analogs & derivatives ; chemistry ; isolation & purification ; pharmacology ; Animals ; Aspergillus ; chemistry ; Chemistry Techniques, Analytical ; Dipeptides ; chemistry ; isolation & purification ; pharmacology ; Enzyme Inhibitors ; chemistry ; isolation & purification ; pharmacology ; Indoles ; chemistry ; isolation & purification ; pharmacology ; Molecular Structure ; Mycobacterium tuberculosis ; drug effects ; Peptides ; chemistry ; isolation & purification ; pharmacology ; Polyketides ; chemistry ; isolation & purification ; pharmacology ; Porifera ; microbiology ; Protein Tyrosine Phosphatases ; chemistry