Arachidonic acid (ARA) is an important essential fatty acid in the human body, and it is also the most abundant and widely distributed polyunsaturated fatty acid in the human body. It is important for maintaining the structure and function of cell membranes in vivo. ARA is widely present in animal tissues, accounting for about 1% in blood phospholipids, heparin and cephalin, about 15% to 40% in adrenal phospholipid fatty acids, and even as high as 70% in nerve endings.
ARA is an important fatty acid. In vivo, ARA can be formed by desaturation and carbon chain extension of linoleic acid. The biological regulation function of linoleic acid is mainly achieved through the metabolites of ARA. ARA also has functions such as regulating cardiac excitability, participating in neuroendocrine, promoting cell division, and inhibiting platelet aggregation.
ARA promotes the repair and growth of skeletal muscle tissue by converting to prostaglandin PGF during and after physical exercise. It not only exists as an extremely important structural lipid in mammalian tissues (especially nerve tissue), but also is an important precursor for the synthesis of prostaglandins in humans, with a wide range of biological activities and important nutritional effects.
Metabolic pathways of ARA
As the precursors of various biologically active substances, there are three main types of enzymes involved in ARA metabolism. The main oxidation reactions that catalyze the metabolism of ARA are: epoxidation, allylic oxidation and Omega- hydroxylation. Under normal physiological conditions, levels of free ARA are very low. When the cell membrane is subjected to various stimuli (such as inflammation), ARA is released from the phospholipid pool, producing a large amount of arachidonic acid, which is converted into biologically active metabolites. In many cells, ARA is released from the cell's endoplasmic reticulum and nuclear envelope and then transported between cells to form biologically active 2-carbon derivatives.