Semisynthetic preparation of 1-O-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (platelet activating factor).

1-O-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (platelet activating factor, PAF), (1.9 mumol) was prepared from the total lipid extract of the protozoan Tetrahymena pyriformis 9 x 10(7) cells. The procedure involved mild alkaline hydrolysis of the total lipids, followed by acetylation and purification of the product by preparative TLC and HPLC. The yield was 60% with respect to the content of 1-O-alkyl-2-acyl-sn-glyceryl-3-phosphorylcholine in the total lipids, determined after preparative TLC. The alkyl side chain of the semisynthetic PAF was composed of hexadecyl residue. Our product was identified as PAF according to its biological activity, the chromatographic behaviour on TLC and HPLC, the physicochemical properties and the behaviour under treatment with PLA2 and Lipase from Rhizopus arrhizus. The above procedure is proposed as a facile, inexpensive and convenient method.