Chemical investigation of the ethyl acetate extract from the marine-derived Streptomyces sp. isolate B1848 resulted in three new isoquinolinequinone derivatives, the mansouramycins E–G (1a–3a), in addition to the previously reported mansouramycins A (5) and D (6). Their structures were elucidated by computer-assisted interpretation of 1D and 2D NMR spectra, high-resolution mass spectrometry, and by comparison with related compounds. Cytotoxicity profiling of the mansouramycins in a panel of up to 36 tumor cell lines indicated a significant cytotoxicity and good tumor selectivity for mansouramycin F (2a), while the activity profile of E (1a) was less attractive.

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Published in Marine Drugs, v. 19, issue 12, 715.

© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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The financial support of this work was funded by a grant from the Bundesministerium für Bildung und Forschung (BMBF, grant 03F0415A).

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Further data are available on request from the corresponding author.

The following are available online at https://www.mdpi.com/article/10.3390/md19120715/s1, NMR spectra and other supplementary data. They are also available for download as the additional file listed at the end of this record.

marinedrugs-19-00715-s001.zip (3214 kB)
Supplementary file