The present invention relates to a peptide or depsipeptide of formula (I) (Y)kX1YZ1X2Z2(Y)m (I),wherein X1 is an α-amino acid residue or an α-hydroxy acid residue of formula (IIa) -A-CR1R2-CO- (IIa),X2 is an α-amino acid residue or an α-hydroxy acid residue of formula (IIb) -A-CR3R4-CO- (IIb),wherein A is NH or O R1 and R3 are independently selected from H, halogen such as F, substituted or unsubstituted C1 to C4 alkyl such as methyl, substituted or unsubstituted aryl and substituted or unsubstituted arylalkyl, aryl being a 5- or 6-membered ring with 0, 1, 2 or 3 heteroatoms, heteroatoms being selected from O, N and S, alkyl in said arylalkyl being C1 to C4 alkyl, said alkyl in said arylalkyl optionally being substituted, the term "substituted", when relating to R1 and R3, providing for, as valence permits, 1, 2, 3, 4, 5, 6, 7 or 8 substituents, said substituents being chosen from halogen such as F R2 and R4 together are chosen to be substituted or unsubstituted n-alk-1,ω-diyl or substituted or unsubstituted n-alken-1,ω-diyl, ω being an integer number selected from 6, 7, 8, 9, 10, 11, 12, 13 and 14, the term "substituted", when relating to R2 and R4, providing for 1 or 2, in case of the substituents being halogen 1, 2, 3, 4, 5, 6, 7 or 8 substituents, said substituents being chosen from halogen such as F and C1 to C4 alkyl such as methyl, said C1 to C4 alkyl in turn optionally being substituted with, as valence permits, 1, 2, 3, 4, 5, 6, 7 or 8 substituents, said substituents being chosen from halogen such as F, and the double bond in said n-alken-1,ω-diyl being at any one of positions 1, 2, 3, 4,... and (ω-1) each occurrence of Y is independently selected to be an α-amino acid or α-hydroxy acid k is an integer number selected from 0, 1, 2, 3, 4, 5, 6 and 7 m is an integer number selected from 1, 2, 3 and 4 Z1 is a polar or negatively charged α-amino acid or α-hydroxy acid and Z2 is a an aliphatic hydrophobic α-amino acid or α-hyd
