Two New Indolyl Diketopiperazines, Trypostatins C and D from Aspergillus penicilliodes Speg

Twelve indolyl diketopiperazines 1-12 were isolated from the mycelia culture of Aspergillus penicilliodes Speg., a dominant microorganism from the post fermentation process of ripe Pu-er tea. Their structures were elucidated by extensive spectroscopic methods. Among them, trypostatins C (1) and D (2) featuring with a rare methyl vinyl ketone side chain at C-2 are new compounds, while 3 and 4 were obtained for the first time from nature source. The isolates 3-12 did not show obvious cytotoxicities against five human cancer cell lines at a concentration of 40 μM.