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Two new pyrrolosesquiterpenes, glaciapyrroles D ( 1 ) and E ( 2 ) were discovered along with the previously reported glaciapyrrole A ( 3 ) from Streptomyces sp. GGS53 strain isolated from deep-sea sediment. This study elucidated the planar structures of 1 and 2 using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), and infrared (IR) spectroscopic data. The absolute configurations of the glaciapyrroles were determined by Mosher's method, circular dichroism spectroscopy, and X-ray crystallography. Under 366 nm UV irradiation, the glaciapyrroles were systematically converted to the corresponding photoglaciapyrroles ( 4 - 6 ) via photoisomerization, resulting in the diversification of the glaciapyrrole family compounds. The transformation of the glaciapyrrole Z to E isomers occurred in a 1:1 ratio, based on virtual validation of the photoisomerization of these olefinic compounds by 1 H-NMR spectroscopy and liquid chromatography/mass spectrometry (LC/MS) analysis. Finally, when encapsulated in poly(lactic-co-glycolic acid) nanoparticles, glaciapyrrole E and photoglaciapyrrole E displayed significant inhibitory activity against influenza A virus. This is the first report of antiviral effects from glaciapyrrole family compounds, whose biological functions have only been subjected to limited studies so far.

New phenazine derivatives with a methylamine linker, Pontemazines A (1) and B (2), were isolated from the culture broth of Streptomyces sp. UT1123. The structures of compounds 1 and 2 were determined by NMR spectroscopy and high-resolution mass spectrometry. These compounds consist of a 9-mehoxyphenazine connected to a benzamide functional group by a unique methylamine linker instead of the more common methyl ether. Pontemazines A and B possess a neuronal cell protective effect on glutamate-induced mouse hippocampal HT-22 cell damage., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Salinazinones A (1) and B (2), two unprecedented pyrrolidinyl-oxazinones, were isolated from the culture broth of Streptomyces sp. KMF-004 from a solar saltern at Aphae Island, Korea. The structures of these salinazinones, which are unusual and consist of 2-methylpropenyl-1,3-oxazin-6-one bearing 1-oxopyrrolidinyl substituents, were assigned by spectral and chemical analyses using Mosher's method, circular dichroism (CD), and calculated ECD. Salinazinones are the first examples of a natural alkaloid class composed of an oxazinone-pyrrolidone conjugate.

Both compounds (I) and (II) are obtained as racemic mixtures and their absolute configurations are not determined. [ABSTRACT FROM AUTHOR]

Compounds (I) and (II) are evaluated for their inhibition activity towards LPS-induced NO-production by BV-2 microglia cells, with (I) inhibiting NO production without cellular toxicity and (II) being inactive. [ABSTRACT FROM AUTHOR]