Lecithin powder (8002-43-5)

Food-grade lecithin is obtained from soybeans and other plant sources. It is a complex mixture of acetone-insoluble phosphatides that consists chiefly of phosphatidyl choline, phosphatidyl etha nolamine, and phosphatidyl inositol, combined with various amounts of other substances such as triglycerides, fatty acids, and carbohydrates. Refined grades of lecithin may contain any of these components in varying proportions and combinations depending on the type of fractionation used. In its oil-free form, the prepon-derance of triglycerides and fatty acids is removed and the product contains 90% or more of phosphatides representing all or certain fractions of the total phosphatide complex. The consistency of both natural grades and refined grades of lecithin may vary from plastic to fluid, depending upon free fatty acid and oil content, and upon the presence or absence of other diluents. Its color varies from light yellow to brown, depending on the source, on crop variations, and on whether it is bleached or unbleached. It is odorless or has a characteristic, slight nutlike odor and a bland taste. Edible diluents, such as cocoa butter and vegetable oils, often replace soybean oil to improve functional and flavor characteris tics. Lecithin is only partially soluble in water, but it readily hydrates to form emulsions. The oil-free phosphatides are soluble in fatty acids, but are practically insoluble in fixed oils. When all phosphatide fractions are present, lecithin is partially soluble in alcohol and practically insoluble in acetone.

Lecithin was first isolated in 1845 by the French chemist and pharmacist Théodore Gobley. In 1850, he named the phosphatidylcholine lécithine. Gobley originally isolated lecithin from egg yolk—λέκιθος lekithos is “egg yolk” in Ancient Greek—and established the complete chemical formula of phosphatidylcholine in 1874; in between, he had demonstrated the presence of lecithin in a variety of biological matters, including venous blood, in human lungs, bile, human brain tissue, fish eggs, fish roe, and chicken and sheep brain.

Lecithin (phosphatidylcholine) is a precursor for choline. As such, it is involved in the synthesis of the neurotransmitter acetylcholine, and levels of lecithin correlate with levels of choline and acetylcholine. Consequently, one presumed mechanism of action of lecithin is the increase in the synthesis, release, and availability of acetylcholine. However, lecithin is also involved in complex intracellular processes, including the regulation of cellular membrane permeability. As discussed above, patients with bipolar disorder reveal altered membrane phospholipid metabolism, and low choline levels within the orbital frontal gray matter have been found in patients with manic symptoms. Thus, supplementation with lecithin apparently stabilizes the membrane and changes action potential.

Pharmaceutical Applications

Lecithins are used in a wide variety of pharmaceutical applications. They are also used in cosmetics and food products.

Lecithins are mainly used in pharmaceutical products as dispersing, emulsifying, and stabilizing agents, and are included in intramuscular and intravenous injections, parenteral nutrition formulations, and topical products such as creams and ointments.

Lecithins are also used in suppository bases, to reduce the brittleness of suppositories, and have been investigated for their absorption-enhancing properties in an intranasal insulin formulation. Lecithins are also commonly used as a component of enteral and parenteral nutrition formulations.

There is evidence that phosphatidylcholine (a major component of lecithin) is important as a nutritional supplement to fetal and infant development. Furthermore, choline is a required component of FDA-approved infant formulas. Other studies have indicated that lecithin can protect against alcohol cirrhosis of the liver, lower serum cholesterol levels, and improve mental and physical performance.

Liposomes in which lecithin is included as a component of the bilayer have been used to encapsulate drug substances; their potential as novel delivery systems has been investigated. This application generally requires purified lecithins combined in specific proportions.

Therapeutically, lecithin and derivatives have been used as a pulmonary surfactant in the treatment of neonatal respiratory distress syndrome.

Research suggests soy-derived lecithin has significant effects on lowering serum cholesterol and triglycerides, while increasing HDL (“good cholesterol”) levels in the blood of rats. However, a growing body of evidence indicates lecithin is converted by gut bacteria into trimethylamine N-oxide (TMAO), which is absorbed by the gut and may with time contribute to atherosclerosis and heart attacks. There is also some preliminary evidence suggesting that excessive consumption of lecithin, either via foodstuffs or supplements, may promote depression in sensitive individuals.

COA

• Paz, P. Esteso, M. C.; Alvarez, M.; Mata, M.; Charorro, C. A.; Anel, L. Development of extender based on soybean lecithin for its application in liquid ram semen. Theriogenology 2010, 74 (4), 663-671.
• Cabezas, D. M.; Diehl, B. W. K.; Tomas, M. C. Sunflower Lecithin: Application of a Fractionation Process with Absolute Ethanol. J. Am. Oil Chemists’ Soc. 2009, 86 (2), 189-196.
• Tsoukalas I (2019). “Too much of a good thing? Lecithin and mental health”. World Nutrition. 10 (1): 54–