Metabolic products of microorganisms. 268. Obscurolides, a novel class of phosphodiesterase inhibitors from streptomyces. II. Minor components belonging to the obscurolide B to D series.

Identification of Obscurolide-Type Metabolites and Antifungal Metabolites from the Termite-Associated Streptomyces neopeptinius BYF101

“…The complete planar structure of compound 2 was confirmed, as shown in Figure 4, based on the key HMBC correlations of H-3′(H-5′)/C-1′, H-3′(H-5′)/ C-7′, H-2′(H-6′)/C-4′, and H-3/C-1′ and the comparison of the NMR spectra of 2 with those of 1. The assigned structure had structural features like those of a previously reported series of obscurolides B, 16 and its MS 2 spectrum had a library match to the same structure in the molecular network (Figure 1). However, despite its inclusion in the GNPS database, the NMR spectroscopic data for the assigned structure of 2 were not reported in any databases or the literature, and its absolute configuration was not verified.…”

“…To the best of our knowledge, compounds 1 and 2 have not been previously reported. In this study, the absolute configuration of compound 3, the planar structure of which had been reported, 16 was verified for the first time.…”

“…Compound 1 was isolated as an amorphous yellow powder, and its molecular formula was determined to be C NMR data of 1 were similar to those of previously reported obscurolides D 2 . 16 The planar structure of 1 was elucidated via interpretation of the 2D NMR data ( 1 H− 1 H COSY and HMBC) (Figure 2). The γ-lactone moiety of 1 was deduced from the key 1 H− 1 H COSY correlations of H-2/H-3/ H-4 and HMBC correlations of H-2/H-3/H-4 to C-1.…”

“…To avoid confusion, we named 1 and 2 following the convention in the original obscurolide publication. 16 In that report, the compounds were named obscurolides A−D based on the form of the side chain attached to C-4, while the form of the functional group attached to C-4′ determined the subdivisions, such as A 1 , A 2 , A 3 , and A 4 . Consequently, 1 and 2 were named obscurolides D 1 and B 1 , respectively.…”

The streptazolin- and obscurolide-type metabolites from soil-derivedStreptomyces albonigerYIM20533 and the mechanism of influence of γ-butyrolactone on the growth ofStreptomycesby their non-enzymatic reaction biosynthesis

“…13,14 Obscurolides, a series of butyrolactone derivatives produced by Streptomyces viridochromogenes (strain Tü 2580), present weak inhibitory activity against phosphodiesterases. 15,16 g-Butyrolactones play an autoregulation role in antibiotic production and differentiation for many members of the genus Streptomyces by modulating the DNA binding activity of cognate receptor proteins. 17 Novel butyrolactones as signaling molecules should be involved in many functional aspects in microbial life, which would be useful for synthetic biology.…”