Five new natural products [asperteramide, aspulvinones R and S, astalluminoxide and astepyrazinol B] and five naturally new ones (aspernolide C, astepyrazinoxide, astepyrazinol A, 4-hydroxy-3-(3 methylbut-2-enyl)benzaldehyde and methyl 2-[4-hydroxy-3-(3-methylbut-2-en-1-yl)phenyl]acetate), together with twenty-one previously described compounds were isolated from marine-derived Aspergillus terreus BCC51799. Chemical structures were determined on the basis of spectroscopic evidence (NMR, UV, IR spectral data) and their physical properties. The isolated compounds were tested for their antimalarial, antimicrobial and anticholinesterase activities. Asperteramide exhibited antimicrobial activity against Bacillus cereus and Colletrichum acutatum with MIC values of 25 and 50 mg/mL, respectively. Astechrome showed strong antimalarial activity with an IC50 value of 0.94 mM, while territrem B had significant anticholinesterase activity with an IC50 value of 0.071 mM. All tested compounds, except for astepyrazinoxide and lavastatin, had moderate to weak cytotoxicity against both cancerous and noncancerous cells.