The present invention relates to an NST500 compound of general formula (I): comprising the following components: X.sub.1--X.sub.2--{(X.sub.3).sub.a/X.sub.4/X.sub.5}--X.sub.6, wherein: X.sub.1 stands for a saturated or unsaturated fatty acid residue comprising 6 20 carbon atoms; or a cysteine residue bound through a thioether bond to a prenyl group comprising 5 20 carbon atoms; said residue being linked to the adjacent component of the compound through an amide bond; X.sub.2 is 0; X.sub.3 comprises 1 6 amino acids, of which 1 6 are positively charged and 0 2 are negatively charged, the other amino acid residues being polar uncharged amino acids; X.sub.4 comprises 1 6 amino acids, of which 1 2 are aromatic amino acids, the other amino acids being selected among polar uncharged amino acids and hydrophobic aliphatic amino acids; X.sub.5 comprises 6 8 amino acids, of which 4 6 are positively charged and 0 2 are negatively charged, the other amino acid residues being polar uncharged amino acids, wherein the amino acids form a cyclic structure; X.sub.6 is a compound of general formula II, wherein Z stands for a spacer group selected among alkane and alkene containing 1 5 carbon atoms, J stands for a functional group selected among amines, thiols, alcohols, carboxylic acids and esters, aldehydes and alkyl halides; U is 0 or is selected among a labeling group; wherein a stands for an integer of 1 3; and the groups X.sub.3, X.sub.4 and X.sub.5 being located at various places in the compound; as well as functional equivalents thereof and/or compounds having the same biological activity thereto. The present also relates to pharmaceutical compositions and methods of using the same.