The first naturally occurring α-methoxylated branched-chain fatty acids from the phospholipids of Amphimedon complanata

The phospholipid fatty acid composition of the sponge Amphimedon complanata was reinvestigated, and the 2-methoxy-13-methyltetradecanoic acid, 2-methoxy-14-methylpentadecanoic acid, and 2-methoxy-13-methylpentadecanoic acid were identified for the first time in nature. Structure characterization was accomplished by means of gas chromatographic retention times and gas chromatography-mass spectrometry. These acids could have originated from bacteria in symbiosis with the sponge.