A compound of the formula I: R-A-Gly-His-B (I) wherein: A and B are independently of each other a L-lysine residue, a D-lysine residue, or a L- or D-lysine residue in which the NH2 group of the side chain comprises a modification, where-in said modification is (i) a replacement with a hydrogen, (ii) an acetylation, (iii) a benzoylation, or (iv) a palmitoylation； GIy is a glycine residue； His is a L- or D-histidine residue； R is CH3&mdash；(CH2)n&mdash；CO&mdash；, wherein n=2, 3, 4, 5, 6, 7 or 8； R&prime； is a group of formula (II): N(Z)(Z&prime；) (II) wherein: Z and Z&prime； is hydrogen, a methyl group, an ethyl group, a phenyl group, an hexyl group, a decyl group or an hexadecyl group； or a racemate, an enantiomer or a diastereomer thereof, or mixtures thereof, or a salt thereof.
