Versiquinazolines L-Q, new polycyclic alkaloids from the marine-derived fungus Aspergillus versicolor.

ABSTRACT: Further chemical examination of a coral-associated fungus Aspergillus versicolor LZD-14-1 by the PHLC-DAD detection resulted in the isolation of six new polycyclic alkaloids, namely versiquinazolines L-Q (1-6). Their structures were determined by extensive analyses of spectroscopic data, including quantum ECD calculation and X-ray single crystal diffraction for the assignment of absolute configurations. Versiquinazoline L bearing a d-Ala residue and versiquinazoline M containing an l-serine residue are rarely found in the fumiquinazoline-type alkaloids, while versiquinazoline P displayed an unusual scaffold with a spiro-γ-lactone. Versiquinazolines P and Q exhibited significant inhibition against thioredoxin reductase (TrxR) with IC₅₀ values of 13.6 ± 0.6 and 12.2 ± 0.7 μM, which showed higher activity than the positive control curcumin (IC₅₀ = 25 μM). The weak cytotoxicity and potent inhibition toward TrxR suggested that versiquinazolines P and Q are potential for microenvironmental regulation of tumor progression and metastasis.

SUBMITTER: Cheng Z 

PROVIDER: S-EPMC9085628 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature