2004 Volume 52 Issue 3 Pages 375-376
A new diketopiperazine alkaloid, golmaenone (1) and related alkaloids, neoechinulin A (2) and L-alanyl-L-tryptophan anhydride (3), have been isolated from the culture broth of the marine-derived fungus Aspergillus sp. The structure and absolute stereochemistry of the new compound (1) was assigned by spectroscopic methods and the advanced Marfey's method. Compounds 1 and 2 exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with IC50 values of 20 and 24 μM, respectively, which are similar to the positive control, ascorbic acid (IC50, 20 μM). Compounds 1 and 2 also showed an ultraviolet-A (UV-A) (320—390 nm) protecting activity with ED50 values of 90 and 170 μM, respectively, which are more active than oxybenzone (ED50, 350 μM) currently being used as sunscreen.
