Structure and stereochemistry of an anti-inflammatory anhydrosugar from the Australian marine sponge Plakinastrella clathrata and the synthesis of two analogues

The structure and relative/absolute configuration of the C-15:0 iso-branched fatty acyl 1,6-anhydropyranose 1 isolated from the Australian marine sponge Plakinastrella clathrata have been investigated. Synthesis of the C-16:0 side chain-modified analogues 3 and 4 has enabled the relative configuration of the C-3 lactate moiety to be secured. In a preliminary anti-inflammatory screening, glycolipid 1 exhibited moderate activity in a PGE2 inhibition assay, however, the compound showed no activity in cytotoxicity screening using 3T3 and P388 cell lines.