Lipids isolated from the cultivated red alga Chondrus crispus inhibit nitric oxide production

A MeOH extract of cultivated Chondrus crispus showed dose-dependent nitric oxide (NO) inhibition of lipopolysaccharide-induced NO production in macrophage RAW264.7 cells. NO inhibition-guided fractionation of the extract led to identification of eicosapentaenoic acid (EPA, 1), arachidonic acid (AA, 2), lutein (3), and eight galactolipids as active components. Based on spectral analysis, the isolated galactolipids were identified as (2S)-1,2-bis-O-eicosapentaenoyl-3-O-beta-d-galactopyranosylglycerol (4), (2S)-1-O-eicosapentaenoyl-2-O-arachidonoyl-3-O-beta-d-galactopyranosylglycerol (5), (2S)-1-O-(6Z,9Z,12Z,15Z-octadecatetranoyl)-2-O-palmitoyl-3-O-beta-d-galactopyranosylglycerol (6), (2S)-1-O-eicosapentaenoyl-2-O-palmitoyl-3-O-beta-d-galactopyranosylglycerol (7), (2S)-1,2-bis-O-arachidonoyl-3-O-beta-d-galactopyranosylglycerol (8), (2S)-1-O-arachidonoyl-2-O-palmitoyl-3-O-beta-d-galactopyranosylglycerol (9), (2S)-1-O-eicosapentaenoyl-2-O-palmitoyl-3-O-(beta-d-galactopyranosyl-6-1 alpha-d-galactopyranosyl)-glycerol (10), and (2S)-1-O-arachidonoyl-2-O-palmitoyl-3-O-(beta-d-galactopyranosyl-6-1 alpha-d-galactopyranosyl)-glycerol (11). All the isolated compounds showed significant NO inhibitory activity. This is the first report of the isolation and identification of individual galactolipids from C. crispus. Moreover, (2S)-1,2-bis-O-arachidonoyl -3-O-beta-d-galactopyranosylglycerol (8) is a novel compound.