Sporochartines A–E

A New Family of Natural Products from the Marine Fungus Hypoxylon monticulosum Isolated from a Sphaerocladina Sponge

Five new sporochartines A to E were isolated from the marine fungus Hypoxylon monticulosum CLL-205, isolated from a sponge belonging to the Sphaerocladina order and collected in Tahiti coast.

The structures of sporochartines A–E were elucidated using 1D and 2D NMR, HRMS and IR data. Their configurations were established according to ROE correlations and comparison with the absolute configuration of sporochartine A, obtained from X-ray analysis. Sporochartines A–D may be derived from endo Diels-Alderase type catalysis between sporothriolide and trienylfuranol A, while and sporochartine E (5) may form through an exo Diels Alderase catalysis between sporothriolide (Sporothriolide but not trienylfuranol A was also isolated from H. monticulosum). The spatial conformation of sporochartines drastically influences the results of the cytotoxic bioassay against HCT-116, PC-3, and MCF-7 human cancer cell lines. Efforts are now focused on the total synthesis of sporochartines.

Regarding these fascinating compounds, which features many unknown biosynthetic steps in the fungus Hypoxylon monticulosum, a collaboration was established with Pr. Russell Cox (director of the “institut für Organische Chemie”, Hanover) to investigate their biosynthesis.