Hydrophobic blue pigment formation from phosphatidylgenipin

Phosphatidylgenipin, synthesized via the transphosphatidylation reaction of 1,2-dipalmitoyl-3-sn-phosphatidylcholine to genipin by phospholipase D, was found to react with L-phenylalanine in chloroform and gave a clear blue solution. This blue solution was also formed in following organic solvents: ethanol, ethyl acetate, diethyl ether, benzene, and hexane. However, genipin and L-phenylalanine did not give any colored product under the same conditions. The blue pigment resulted from phosphatidylgenipin and L-phenylalanine showed lambda max at 615 nm in chloroform, and had a similar blue color to an aqueous solution of the natural blue pigment "gardenia blue." This is an example for the preparation of a hydrophobic pigment from a phosphatidyl derivative of a water-soluble compound.