New antioxidative secondary metabolites from the fruits of a Beibu Gulf mangrove, Avicennia marina.

Further chemical investigation of the fruits of the mangrove, Avicennia marina, afforded three new phenylethyl glycosides, marinoids J-L (1-3), and a new cinnamoyl glycoside, marinoid M (4). The structures of isolates were elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of related secondary metabolites. The antioxidant activity of the isolates was evaluated using the cellular antioxidant assay (CAA), and compounds 1-4 showed antioxidant activities, with EC50 values ranging from 23.0 ± 0.71 μM to 247.8 ± 2.47 μM.