Saccharobisindole, neoasterric methyl ester, and 7‐chloro‐4(1h)‐quinolone: Three new compounds isolated from the marine bacterium saccharomonospora sp.

Abstract

Analysis of the chemical components from the culture broth of the marine bacterium Saccharomonospora sp. CNQ‐490 has yielded three novel compounds: saccharobisindole (1), neoasterric methyl ester (2), and 7‐chloro‐4(1H)‐quinolone (3), in addition to acremonidine E (4), pinselin (5), penicitrinon A (6), and penicitrinon E (7). The chemical structures of the three novel compounds were elucidated by the interpretation of 1D, 2D nuclear magnetic resonance (NMR), and high‐resolution mass spectrometry (HRMS) data. Compound 2 generated weak inhibition activity against Bacillus subtilis KCTC2441 and Staphylococcus aureus KCTC1927 at concentrations of 32 μg/mL and 64 μg/mL, respectively, whereas compounds 1 and 3 did not have any observable effects. In addition, compound 2 displayed weak anti‐quorum sensing (QS) effects against S. aureus KCTC1927 and Micrococcus luteus SCO560. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.