ABSTRACT
Inthomycins are polyketide antibiotics which contain a terminal carboxamide group and a triene chain. Inthomycin B (1) and its two new analogues 2 and 3 were isolated from the crude extract of Streptomyces pactum L8. Identification of the gene cluster for inthomycin biosynthesis as well as the N-labeled glycine incorporation into inthomycins are described. Combined with the gene deletion of the rare P450 domain in the NRPS module, a formation mechanism of carboxamide moiety in inthomycins was proposed via an oxidative release of the assembly chain assisted by the P450 domain.
ABSTRACT
Lobane-type diterpenoids are not frequently discovered from marine soft corals. In this paper, three new lobane type diterpenes, 13-methoxyloba-8,10,15(16),17(18)-tetraene (1), 8,10,13(15)Z,16E-lobatetraene (2) and 19-hydroxy-lobatetraene (3), and a new natural compound, 17,18-epoxyloba-16-acetoxy-8,10,13(15)-trien (4), co-occurring with a known related diterpenoid, 18-methoxyloba-8,10,13(15),16(17)-tetraene (5), were isolated from the South China Sea soft coral Sinularia polydactyla. The structures of new compounds were determined by extensive spectroscopic analysis and by comparison with those reported in the literature. In bioassay, all the isolates were inactive on antibacterial, PTP1B inhibitory, and immunological activities. This study increased the chemical diversity of marine diterpenoids.
ABSTRACT
One new sorbicillin derivative, 2-deoxy-sohirnone C (1), one new diketopiperazine alkaloid, 5S-hydroxynorvaline-S-Ile (2), and two naturally occurring diketopiperazines, 3S-hydroxylcyclo(S-Pro-S-Phe) (3) and cyclo(S-Phe-S-Gln) (4), together with three known compounds were isolated from the Chinese mangrove endophytic fungus Penicillium sp. GD6. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison with literature data. The absolute configuration of 3-hydroxyl moiety in 3 was determined by Mosher's method, while the absolute stereochemistry of 2 and 4 was established by comparison with the CD spectra of natural and synthesized diketopiperazines. Compound 1 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with a MIC value of 80 μg·mL.
Subject(s)
Alkaloids , Chemistry , Anti-Bacterial Agents , Chemistry , Pharmacology , China , Circular Dichroism , Diketopiperazines , Chemistry , Methicillin-Resistant Staphylococcus aureus , Microbial Sensitivity Tests , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Penicillium , Chemistry , Resorcinols , Chemistry , Pharmacology , Rhizophoraceae , Microbiology , WetlandsABSTRACT
One new sorbicillin derivative, 2-deoxy-sohirnone C (1), one new diketopiperazine alkaloid, 5S-hydroxynorvaline-S-Ile (2), and two naturally occurring diketopiperazines, 3S-hydroxylcyclo(S-Pro-S-Phe) (3) and cyclo(S-Phe-S-Gln) (4), together with three known compounds were isolated from the Chinese mangrove endophytic fungus Penicillium sp. GD6. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison with literature data. The absolute configuration of 3-hydroxyl moiety in 3 was determined by Mosher's method, while the absolute stereochemistry of 2 and 4 was established by comparison with the CD spectra of natural and synthesized diketopiperazines. Compound 1 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with a MIC value of 80 μg·mL.
Subject(s)
Alkaloids , Chemistry , Anti-Bacterial Agents , Chemistry , Pharmacology , China , Circular Dichroism , Diketopiperazines , Chemistry , Methicillin-Resistant Staphylococcus aureus , Microbial Sensitivity Tests , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Penicillium , Chemistry , Resorcinols , Chemistry , Pharmacology , Rhizophoraceae , Microbiology , WetlandsABSTRACT
<p><b>OBJECTIVE</b>To study the non-taxoids in the leaves of Taxus mairei.</p><p><b>METHOD</b>The chemical constituents were isolated by chromatography and identified by spectral data.</p><p><b>RESULT</b>Five compounds, taxamairin A (1), taxamairin B (2), sciadopitysin (3), ( - ) matairesinol (4), ponasterone A (5) were isolated and identified.</p><p><b>CONCLUSION</b>Compounds 3-5 were isolated from this plant for the first time, compounds 1 and 2 were isolated from the leaves of T. mairei for the first time.</p>