Oxo and Methoxy Fatty Acids

Oxo fatty acids and also methoxy fatty acids are very rare species in nature. Oxo fatty acids may either occur as ketonic or aldehydic fatty acids. Particularly aldehydic fatty acids are often artifacts resulting from nonenzymatic fatty acid oxidation of polyunsaturated fatty acids. The most well-described keto species is 9-keto-trans-2-decenoic acid. This lipid is an active compound of bee royal jelly and has pheromone function in insect biology. Other keto fatty acids with 16–30 carbons are described in plants or fungi like, for example, γ-ketocrotonic acid (4-keto-2-hexadecenoic acid). Aldehydic fatty acids like traumatin (12-keto-9-dodecenoic acid) are mostly known in plants. The biological role of traumatin is in defense signaling. Methoxy groups can be found quite commonly in mycolic acids. Other than that methoxy fatty acids are very rare and can only be found as two methoxylated compounds with up to 24 carbons and up to two double bonds in tropic sponges. Fatty acids with...