Cristatumins A–D, new indole alkaloids from the marine-derived endophytic fungus Eurotium cristatum EN-220

Four new indole alkaloids, namely, cristatumins A–D (1–4), along with six known congeners (5–10) were identified from the culture extract of Eurotium cristatum EN-220, an endophytic fungus isolated from the marine alga Sargassum thunbergii. The structures of these compounds were established on the basis of extensive spectroscopic analysis. Each of these compounds was evaluated for antimicrobial and insecticidal activity. Compounds 1 and 9 showed antibacterial activity against Escherichia coli and Staphyloccocus aureus, respectively, while compounds 2, 6, and 7 exhibited moderate lethal activity against brine shrimp. Preliminary structure–activity relationships were also discussed.