Lecithin and Phosphatides

Heidi Li

Lecithin is the most common natural phospholipid that is found in many animal tissues and organs as an important constituent of biological membranes. It is also widespread in the plant world and abundant in legumes, cereals and seed embryos. Vegetable lecithin is the main constituent of commercially available sources, in which the majority of lecithin is derived from soybeans. Lecithin's biological and physiological properties make it useful in the pharmaceutical, food and cosmetics fields. Moreover, it is widely used for a dietary supplement to aid in memory and cognitive function, cardiovascular health and liver function.

Lecithin from soybean sources is a complex mixture of phosphatides that contains mainly of Phosphatidylcholine (PC), Phosphatidyethanilamine (PE) and Phosphatidylinositol (PI) with minor amount of Phosphatidic acid (PA), Phosphatidylserine (PS), and corresponding lysophosphatidyl derivatives (LPC, LPE, LPI, and LPS). Neutral lipids, free fatty acids, carbohydrates and other components are also present in soy lecithin. High-purity PC and PE, the fraction products of phospholipids, were extensively applied in the fields of nourishment, pharmaceuticals and cosmetics. Among PC, PE and other phosphatides, PC is one of important active ingredients, which acts as a vehicle for essential fatty acids to promote metabolism through the cell membrane. Research has shown that Phosphatidylcholine is beneficial in depression, memory loss and neurological disorders.

The composition of lecithin is largely dependent on lecithin source and degree of purification. Owing to the difficulty of obtaining lecithin PC and PE of sufficient purity, it is important to develop rapid and effective analytical methods for the purpose of quality control and to discover any commercial frauds. HPLC technique has been widely used to develop selective and specific assays, which are required by current pharmaceutical regulations. HPLC analysis of lipids is a comparatively less developed field of application of this technique. American Oil Chemistry Organization (AOCS) established an HPLC method to determine PC, PE and PI in Lecithin by HPLC, which is validated and mostly performed for analysis lecithin. This HPLC method allows separation between different classes of lipids and between individual compounds within a certain class.

NOW Foods carries variety of lecithin products, including Lecithin powder, granule and softgel. To ensure the quality of these products, we have developed HPLC method based on official AOCS method to validate analytical procedure for testing PC, PE and PI. This analytical method is accurate, efficient and simultaneous to determine typical levels of various phosphatidylcholine compounds to ensure the quality of our lecithin products.


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M.A. Yorek In: G. Cevc, Editor, Phospholipids Handbook, Marcel Dekker, New York (1993), p. 745