Fatty acids are important components of lipids (such as triglycerides and phospholipids) in living organisms. From a chemical perspective, they belong to a class of organic compounds composed of long-chain hydrocarbon groups and terminal carboxyl groups (-COOH). Their carbon chain lengths and degrees of saturation vary. Based on the presence or absence of double bonds in their carbon chains, fatty acids can be classified into saturated fatty acids and unsaturated fatty acids. Among these, unsaturated fatty acids have received considerable attention due to their importance to human health.
Fatty acids serve multiple purposes in organisms. They are not only essential building blocks of cell membranes, influencing their fluidity and function, but also the primary form of energy storage in organisms. Through β-oxidation, they provide cells with a significant amount of energy. Furthermore, some fatty acids, especially essential fatty acids, are precursors to signaling molecules with regulatory functions, such as arachidic acid.
The main sources of fatty acids include natural extraction and biosynthesis. In nature, they are widely found in the fats and oils of animals and plants, such as animal fats, vegetable oils (e.g., olive oil, soybean oil, fish oil), and microbial lipids. They usually exist in the form of triglycerides or phospholipids, and rarely in a free form. In addition, organisms can also synthesize long-chain fatty acids in the cytoplasm and endoplasmic reticulum using precursors such as acetyl-CoA and NADPH through fatty acid synthesis pathways.
