One new prenylated indole diketopiperazine alkaloid, named dihydroneochinulin B (1), one known spiro-polyketide-diketopiperazine hybrid cryptoechinuline D (2) and three related known metabolites didehydroechinulin B (3), neoechinulin B (4) and auroglaucin (5) were isolated from the mangrove rhizosphere soil derived fungus, Aspergillus effuses H1-1. The structures were assigned by detailed spectroscopic analysis. The enantiomers of cryptoechinuline D (2) were separated to be (+)-cryptoechinuline D (2a) and (-)-cryptoechinuline D (2b) by chiral HPLC, and their absolute configurations were determined by ECD analysis. The cytotoxic effects of the compounds were preliminarily evaluated on P388, HL-60, BEL-7402 and A-549 cell lines by SRB or MTT methods, and compounds 2, 2a and 3 showed significant activities.