Objective: The secondary metabolites of marine fungus Aspergillus aculeatus CGD12 and their antibacterial activities were investigated. Method: Column chromatography on silica gel

ODS

Sephadex LH-20 and semipreparative HPLC were used to isolate and purify the compounds from EtOAc extract of the fermentation broth. Their structures were elucidated by NMR

MS spectroscopics data analyses and compared with the data of reported literatures. In order to evaluate the antibacterial activities of these compounds

microdilution broth method was adopted. Result: Seven compounds were isolated from the fermentation broth of A. aculeatus CGD12 and identified as versiol (1)

JBIR74(2)

JBIR75(3)

cyclo-(L-Pro-L-Tyr)(4)

cyclo-(L-Pro-L-Val)(5)

cyclo-(L-Pro-L-Ile)(6)

cyclo-(L-Ala-L-Leu)(7). Conclusion: Compounds 4 and 7 show antibacterial activities against Staphyloccocus aureus and S. epidermidis. The weak antibacterial activities which against Pseudomonas aeruginosa

Klebsiellar pneumonia and Escherichia coli of compound 3 are reported for the first time.