Lecithins (cholinophosphatides) are esters of glycerol, phosphoric and fatty (oleic, palmitic and stearic ) acids. Lecithins are found in tissues with highly intensive metabolism: in the substance of the brain, liver, kidneys, heart muscle, etc. Lecithins promote the transport of neutral fats, counteract the excessive deposition of cholesterol in the vessels. Lecithins have a beneficial effect on metabolism, especially of a growing body, improve bone growth , have a healing effect on symptoms of nervous depletion, anemia, general exhaustion, vascular hypotension , and liver cirrhosis . Let out under the name "lecithin-cerebro" (Lecithinum-cerebro) in pills of 0.1 g. Assigned 1-2 tablets 3 times a day. Lecithin along with phosphorus , iron and calcium salts is included in the preparation phosphrene (see), appointed for the same indications. Lecithins are stored in a dark place.
Lecithins are compounds related to lipids, but they can also be considered as derivatives of triglycerides (neutral fats), in which one of the residues of the fatty acid molecule is replaced by choline phosphate ester. Of the two remaining fatty acid lecithin molecules, one (R) is saturated (stearic or palmitic), and the other (R ') is unsaturated (oleic, linoleic, or arachidonic). Depending on the position of the substituted fatty acid, α- and β-lecithins are distinguished.
Lecithins are white, waxy substances, soluble in methyl and ethyl alcohols, ether and chloroform (but not in acetone), insoluble in water, but easily forming emulsions. Lecithins are widely distributed in the body of all animals: they are found in significant quantities in the brain and spinal cord, liver, kidneys, and heart muscle. In cells, they are permanent components of both the outer membranes and the membranes of subcellular structures, and the permeability of these membranes for various substances is largely determined. In the blood, lecithins are found in erythrocytes and in plasma, and most of the lecithins in plasma are associated with proteins and are part of the lipoproteins (see).Go
The exchange of lecithins is carried out basically the same way as triglycerides. In the intestine, they are broken down by various lecithinases secreted by the pancreas. Lecithinase A cleaves the unsaturated fatty acid molecule, resulting in the formation of lysolecithin. Lysolecithin has a pronounced hemolytic effect, but immediately splits further with the participation of lecithinase B, which splits off the saturated fatty acid molecule to form glycerylphosphorylcholine, which then decomposes into glycerol and phosphorylcholine under the action of phosphatases. In the intestine, there are also enzymes that initially cleave choline from lecithins, and phosphatidic acid is formed, which is able to be absorbed in a thin emulsion without further cleavage. Resynthesis of lecithin from its decay products in the intestine occurs partially in the wall of the intestine itself, and then in the liver and other organs, and this process takes place mainly in the mitochondria of cells. The rate of synthesis of lecithin in the brain (as in other organs) depends on its functional state: during inhibition, this synthesis decreases markedly, and when it is excited, it increases.
The intensity of the synthesis of lecithins in the liver plays a very large role in fat metabolism (see): lecithins leave the liver much faster than neutral fats, and are the best carriers of fatty acids between the liver, organs and fat depots. Therefore, if there is insufficient lecithin formation in the liver, for example, due to the lack of choline in the food, liver obesity easily occurs. See also Phosphatides.
Lecithin as a drug is used for diseases of the nervous system, general loss of strength, anemia and vascular hypotension, as well as for some chronic skin lesions, some forms of childhood eczema, etc.
In medical practice, lecithin (Lecithinum), lecithin-cerebro (Lecitliinum-cerebro) and lipocerebrin (Lipoce-rebrinum) are used. These preparations are obtained by extraction from the liver and brain of cattle. Lecithin and lecithin-cerebro are produced in the form of dragees (0.1 g of lecithin in one piece); daily dose - 3-6 tablets. Lipocerebrin is available in tablets (0.5 g each) and in ampoules (aqueous suspension of lipoid substances, 1 ml each) for intramuscular injections; daily dose - 3 times 1-2 tablets or 1 ml of suspension. Keep in a dry, dark place.