A New Ergosterol Analog, a New Bis-Anthraquinone and Anti-Obesity Activity of Anthraquinones from the Marine Sponge-Associated Fungus Talaromyces stipitatus KUFA 0207

Abstract

A new ergosterol analog, talarosterone ( 1) and a new bis-anthraquinone derivative ( 3) were isolated, together with ten known compounds including palmitic acid, ergosta-4,6,8(14),22-tetraen-3-one, ergosterol-5,8-endoperoxide, cyathisterone ( 2), emodin ( 4a), questinol ( 4b), citreorosein ( 4c), fallacinol ( 4d), rheoemodin ( 4e) and secalonic acid A ( 5), from the ethyl acetate extract of the culture of the marine sponge-associated fungus Talaromyces stipitatus KUFA 0207. The structures of the new compounds were established based on extensive 1D and 2D spectral analysis, and in the case of talarosterone ( 1), the absolute configurations of its stereogenic carbons were determined by X-ray crystallographic analysis. The structure and stereochemistry of cyathisterone ( 2) was also confirmed by X-ray analysis. The anthraquinones 4a– e and secalonic acid A ( 5) were tested for their anti-obesity activity using the zebrafish Nile red assay. Only citreorosein ( 4c) and questinol ( 4b) exhibited significant anti-obesity activity, while emodin ( 4a) and secalonic acid A ( 5) caused toxicity (death) for all exposed zebrafish larvae after 24 h.