Eicosanoic

Eicosanoic refers to a fatty acid with a chain of twenty carbon atoms. The most common and biologically significant eicosanoic acid is eicosanoic acid itself, also known as arachidic acid. This is a saturated fatty acid, meaning its carbon chain contains no double bonds. Saturated fatty acids are typically solid at room temperature. Eicosanoic acid is found in small amounts in various animal and vegetable fats and oils, including peanut oil, cocoa butter, and butterfat.

While arachidic acid is a saturated fatty acid, the term "eicosanoic" can also be used in a broader sense to describe any fatty acid with a twenty-carbon chain, regardless of saturation. For example, eicosenoic acids would be unsaturated fatty acids with a twenty-carbon chain, containing one or more double bonds. These unsaturated derivatives play roles in various biological processes. The length of the carbon chain is a key characteristic in classifying fatty acids, and the twenty-carbon length places them within the category of long-chain fatty acids.