Soy (Glycine max)-Derived Phospholipids Exhibit Potent Anti-Apoptotic Activity

We have isolated and identified a soybean phospholipid mixture from unroasted soy (Glycine max) flour that is a potent inhibitor of apoptotic cell death. This phospholipid mixture has been purified from several soy derived materials including soy flour soy molasses, and crude commercial soy lecithin. Analysis of this bioactive lipid mixture has identified the two major constituents as phosphatidic acid and phosphatidylinositol. This lipid mixture also contains lesser amounts of lysophosphatidic acid, lysophosphatidylinositol, and lysophosphatidylcholine. These phospholipids contain the typical distribution of fatty acids found in soy, predominantly C16:0 and C18:2 (hexadecanoic and 9,12-octadecadienoic) in a 60:40 to 50:50 ratio. Less than 10% of other varieties of fatty acids were identified; the most common other fatty acids found were C18:0, C18:1 and C18:3. Apoptosis inhibition was assessed following serum deprivation of a mouse embryonic stern cell line (C3H-10T1/2). This anti-apoptotic bioassay was used to monitor the purification of the bioactive phospholipid mixture. Of the phospholipids contained in the mixture, lysophosphatidic acid was found to be the most potent inhibitor of apoptotic cell death. The anti-apoptotic factor described here is distinct from the bioactive, well characterized estrogen-like, anti-cancer factor and the Bowman-Birk protease inhibitor neither of which possess anti-apoptotic activity in this assay.