Six previously undescribed prenylated indole diketopiperazine alkaloids, talaromyines A -F ( 1 - 6 ), were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures including absolute configurations were elucidated on the basis of comprehensive spectroscopic data including NMR, HR-ESI-MS, and electronic circular dichroism calculations, together with chemical analysis of hydrolysates. Compounds 1 - 5 represent the first example of spirocyclic indole diketopiperazines biosynthesized from the condensation of L-tryptophan and L -alanine. Compounds 2 and 4 - 5 showed selective inhibitory activities against phosphatases TCPTP and MEG2 with IC 50 value of 17.9 - 29.7 mu M, respectively. Compounds 4 - 5 exhibited mild cytotoxic activities against two human cancer cell lines H1975 and HepG-2.