Anthraquinone Derivatives and an Orsellinic Acid Ester from the Marine Alga‐Derived Endophytic Fungus Eurotium cristatum EN‐220

Abstract

AbstractCultivation of the fungal strain Eurotium cristatum EN‐220, an endophyte obtained from the marine alga Sargassum thunbergii, resulted in the isolation of one new anthraquinone glycoside, 3‐O‐(α‐D‐ribofuranosyl)questinol (1) and one new orsellinic acid ester, cristatumside A (2), together with three known aromatic glycosides, 3‐O‐(α‐D‐ribofuranosyl)questin (3), isotorachrysone 6‐O‐α‐D‐ribofuranoside (4), and asperflavin ribofuranoside (5), as well as three anthraquinone derivatives, asperflavin (6), eurorubrin (7), and (+)‐variecolorquinone A (8). The structures of these compounds were determined by extensive analysis of their spectroscopic data, as well as by their comparison with those in the literature. Each of the isolated compounds was evaluated for its antimicrobial activity and brine shrimp lethality.