New polyketides and new benzoic acid derivatives from the marine sponge-associated fungus Neosartorya quadricincta KUFA 0081

Two new pentaketides, including a new benzofuran-1-one derivative (1) and a new isochromen-1-one (5), and seven new benzoic acid derivatives, including two new benzopyran derivatives (2a, b), a new benzoxepine derivative (3), two new chromen-4-one derivatives (4b, 7) and two new benzofuran derivatives (6a, b), were isolated, together with the previously reported 2,3-dihydro-6-hydroxy-2,2-dimethyl-4H-1-benzopyran-4-one (4a), from the culture of the marine sponge-associated fungus Neosartorya quadricincta KUFA 0081. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compounds 1, 2a, 4b, 5, 6a and 7, the absolute configurations of their stereogenic carbons were determined by an X-ray crystallographic analysis. None of the isolated compounds were active in the tests for antibacterial activity against Gram-positive and Gram-negative bacteria, as well as multidrug-resistant isolates from the environment (MIC > 256 μg/mL), antifungal activity against yeast (Candida albicans ATTC 10231), filamentous fungus (Aspergillus fumigatus ATTC 46645) and dermatophyte (Trichophyton rubrum FF5) (MIC > 512 μg/mL) and in vitro growth inhibitory activity against the MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (melanoma) cell lines (GI50 > 150 μM) by the protein binding dye SRB method. © 2016 by the authors; licensee MDPI.

This work was developed in the Natural Products Research Laboratory of the Department of Chemistry, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), of the University of Porto and partially supported through national funds provided by FCT-Foundation for Science and Technology and European Regional Development Fund (ERDF) and COMPETE, under the projects PEst-C/MAR/LA0015/2013, PTDC/MAR-BIO/4694/2014, as well as by the project INNOVMAR (Innovation and Sustainability in the Management and Exploitation of Marine Resources) (Reference NORTE-01-0145-FEDER-000035, within Research Line NOVELMAR/INSEAFOOD/ECOSERVICES), supported by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). We thank Mrs. Júlia Bessa and Sara Cravo for technical support.