Euroticins C-E, Three Pairs of Polycyclic Salicylaldehyde Derivative Enantiomers from a Marine-Derived Fungus Eurotium sp. SCSIO F452

Euroticins C–E (1–3), three pairs of salicylaldehyde derivative enantiomers, were isolated from a marine-derived fungus Eurotium sp. SCSIO F452. They represent two types of salicylaldehyde derivatives bearing unprecedented highly constructed 6/6/6/6 tetracyclic structures. Their structures were established by comprehensive spectroscopic analyses, X-ray diffraction, and electronic circular dichroism calculations. Compounds (+)-1 and (−)-1 showed significant antioxidative activity and moderate cytotoxic activity.