Thiodiketopiperazines with two spirocyclic centers extracted from Botryosphaeria mamane, an endophytic fungus isolated from Bixa orellana L.

Abstract Three thiodiketopiperazines, botryosulfuranols A-C (1 – 3) were isolated from the endophytic fungus Botryosphaeria mamane . The three compounds present sulfur atoms on α- and β- positions of phenylalanine derived residues and unprecedented two spirocyclic centers at C-4 and C-2′. Their planar structures were determined by spectroscopic analysis and absolute configurations were achieved by X-ray diffraction analysis and ECD and NMR chemical shifts calculations. Botryosulfuranol A ( 1 ) was the most cytotoxic compound against four cancer cell lines (HT-29, HepG2, Caco-2, HeLa) and two healthy cell lines (IEC6, Vero) highlighting the importance of an electrophilic center for cell growth inhibition.