Peyssonenynes a and B, Novel Enediyne Oxylipins with DNA Methyl Transferase Inhibitory Activity from the Red Marine Alga Peyssonneliacaulifera

Two novel omega3 fatty acids, obtained as monoacyl glycerol derivatives, were isolated as DNA methyl transferase inhibitors following bioassay-guided fractionation of the Fijian red marine alga Peyssonnelia caulifera. Both active metabolites, peyssonenynes A (1) and B (2), possess an unusual enediyne motif, whereas an inactive co-metabolite, peyssopyrone (3), contains an unusual gamma-pyrone functionality. The molecular structures of all three compounds were determined by NMR spectroscopy in combination with UV, IR, and MS data analysis. The instability of the enediyne monoacyl glycerol derivatives prevented their complete stereochemical assignments.