One diketopiperazine (1) and three phenols (3, 5 and 6) were isolated from static culture of Antarctic fungus,Penicillium citreonigrum SP-6, as well as their structures were determined by NMR and CD spectroscopic methods.Additionally, two known compounds, cyclo-(L-Trp-L-Phe) (2) and (-)-(3S, 10R)-dichlorodiaportal (4), wereisolated and identified. Antitumor biological studies demonstrated that compounds 1 and 3 showed weak inhibitions against HCT116 cancer cell lines with IC50 values of 26.7 and 46.3 μM, respectively, comparing to cisdichlorodiamine platinum.