Safety Assessment of Lecithin and Other Phosphoglycerides as Used in Cosmetics.

The phosphoglycerides considered in this safety assessment are reported to function primarily as skin and hair conditioning agents, emulsifying agents, and surfactants in cosmetic products and are used up to a maximum reported concentration of 50%. Although phospholipids exert physiologic effects, these are not reproduced by application of phospholipid ingredients to the skin. Given the possibility that Lecithin may be derived from animal sources, it should be noted that the Food and Drug Administration does not permit the use of ingredients made from bovine specified risk materials in cosmetic products. The Expert Panel for Cosmetic Ingredient Safety concluded that the 17 phosphoglycerides are safe in the present practices of use and concentration in cosmetics, as described in this safety assessment.

Glucosamine-glycerophospholipids that activate cell-matrix adhesion and migration.

Two new analogues derived from the platelet activating factor (PAF), containing glucosamine instead of the acetyl group, were synthesized, and their effect on the human keratinocyte cell line HaCaT was evaluated with respect to cytotoxicity, proliferation, adhesion, and migration. Starting with (R)-1,2-isopropylideneglycerol (3), the glycosylation acceptor 1-O-octadecyl-3-O-tert-butyldimethylsilyl-sn-glycerol (6) was synthesized in three steps. Glycosylation of 6 with the already known O-(3,4,6-tri-O-acetyl-2-deoxy-2-dimethylmaleimido-beta-D-glycopyranosyl)trichloracetimidate gave 1-O-octadecyl-2-O-(3',4',6'-tri-O-acetyl-2'-deoxy-2'-dimethylmaleimido-beta-D-glucopyranosyl)-3-O-tert-butyldimethylsilyl-sn-glycerol (7). After removing the (tert-butyldimethyl)silyl (TBDMS) group with FeCl3x6H2O, phosphoryl choline was introduced, yielding [1-O-octadecyl-2-O-(2'-deoxy-2'-dimethylmaleimido-beta-D-glucopyranosyl)-sn-glycero(3)]phosphorylcholine (2) (glucosimide-PAF). pH controlled cleavage of the amino protection group gave [1-O-octadecyl-2-O-(2'-deoxy-2'-amino-beta-D-glucopyranosyl)-sn-glycero(3)]phosphorylcholine hydrochloride (1) (glucosamine-PAF). 2 inhibited proliferation of HaCaT cells by 26% at nontoxic concentrations, while 1 increased the proliferation rate by 30% at low concentrations. At higher concentrations, both compounds showed cytotoxic properties with LD50 = 30 micromol/L (1) and LD50 = 5-6 micromol/L (2). Both 1 and 2 were potent promoters of cell adhesion and migration of HaCaT cells.