Isolation, Stereochemical Study, and Cytotoxic Activity of Isobenzofuran Derivatives From a Marine Streptomyces sp.

Abstract

A new 1,3-dihydroisobenzofuran derivative (), together with its epimer (), was isolated from marine Streptomyces sp. W007. The structure of the two compounds was established by extensive spectroscopic analysis and comparison with reported data. The absolute configurations of and were determined by a combination of experimental and computational means, including J-coupling analysis and nuclear Overhauser effect spectroscopy (NOESY) spectra, nuclear magnetic resonance (NMR) calculations, electronic circular dichroism (ECD), and optical rotation (OR) calculations. Compound had no cytotoxicity against human lung adenocarcinoma cell line A549, while compound exhibited weak activity, suggesting that the biological activity depends on the configuration of a single chirality center.

Bioactive Secondary Metabolites with Unique Aromatic and Heterocyclic Structures Obtained from Terrestrial Actinomycetes Species

“…20) In 2015, Shen and colleagues also isolated a compound with identical spectral data to Xie's 2012-isomer (6) from Streptomyces sp. CB01913 and suggested that the H-9/H-16 configuration of the 2012-isomer had to be revised as trans.…”

“…W007 in 2012, 19) and also isolated an epimer of the 1,3-dihydroisobenzofuran in 2015 (=2015-isomer). 20) The first 1,3-dihydroisobenzofuran isolated in 2012 (=2012-isomer) was initially proposed to have a cis H-9/H-16 configuration.…”

“…However, they reassigned the H-9/H-16 configuration of the 2012-isomer as trans in 2015 (6) and that of the 2015-isomer as cis (7), respectively, 20) and their absolute configurations were also proposed on the basis of electronic circular dichroism (CD) spectra along with time-dependent density functional theory (TDDFT) calculations. 20) In 2015, Shen and colleagues also isolated a compound with identical spectral data to Xie's 2012-isomer (6) from Streptomyces sp.…”

Elmenols C-H, new angucycline derivatives isolated from a culture of Streptomyces sp. IFM 11490

“…It was also supported by comparing its spectral data with the known related (-)- 1,4-dimethoxy-3-(3′-hydroxy-3′-methyl-1′-tetralone)-1(3H)-isobenzofuran. 21 HMBC correlations from H-3 to C-7′ through 3 J coupling revealed the connectivity of the 1,3-dihydroisobenzofuran fragment to C-8′ of the tetralone moiety. The relative configuration of 1 was assigned by an analysis of the NOESY spectrum and proton coupling constants ( Table 1).…”

“…The MW of the mixture was 350 Daltons based on (+)-ESIMS. The molecular formula was estimated to be C 21 revealed one oxygenated methine proton, two methoxy groups, and one methyl signal. The 13 C NMR data (Table 2) of 3 and 4 showed seven aromatic methines, eleven quaternary carbon atoms, two methoxy groups, and one methyl carbon.…”