Tetrahydroanthraquinone derivatives from the mangrove-derived endophytic fungus Stemphylium globuliferum

Abstract

Two new tetrahydroanthraquinone derivatives, altersolanol Q (1) and 10-methylaltersolanol Q (2), and the new dimer alterporriol X (3), together with 13 known analogues were isolated from white bean solid culture media of the endophytic fungus, Stemphylium globuliferum, obtained from the Egyptian mangrove plant Avicennia marina. The present study resulted in the production of a large diversity of secondary metabolites including new derivatives. Their structures were elucidated using one- and two-dimensional NMR spectroscopy as well as HRESIMS. The absolute configurations of the new compounds 1–3 were determined by TDDFT-ECD calculations or by comparing ECD data with those of known analogues. Compounds 1–3 were tested against the L5178Y mouse lymphoma cell line but proved to be inactive in contrast to some of the known compounds such as altersolanol A (6) that were likewise isolated in this study.