A new Butenolide Derivative from the Brown Alga Sargassum micracanthum

A new butenolide derivative (1), along with three known compounds (2-4) were isolated from the MeOH extract of brown alga Sargassum micracanthum. The structures of 1 to 4 were determined by the analyses of 1D and 2D NMR and mass spectroscopic data. The known compounds (2-4) were identified as (5E,10Z)-6,10,14-trimethylpentadeca-5,10-dien-2,12-dione (2), (5E,9E)-6,10,14-trimethylpentadeca-5,9-dien-2,12-dione (3), and (-)-loliolide (4) by comparing with their published spectroscopic data. The antioxidant activities of compounds 1 to 4 were evaluated based on using 2,2 '-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Compounds 1 to 4 were inactive at the concentration of 200 mu M.