Seven novel macrocyclic polypeptides from Viola arvensis

Seven novel macrocyclic polypeptides, designated as vary peptides B-H, have been isolated from the aerial parts of Viola arvensis. Their primary structures have been elucidated by automated Edman degradation and mass spectrometry. They all consist of 29 or 30 amino acid residues, covalently cyclized via the amide backbone and by three internal disulfide bridges. Their amino acid sequences are as follows: vary peptide B, cyclo-(TCFGGTCNTPGCSCDPWPMCSRNGLPVCGE); varv peptideC, cyclo(TCVGGTCNTPGCSCSWPVCTRNGVPICGE); vary peptide D, cyclo-(TCVGGSCNTPGCSCSWPVCTRNGLPICGE); vary peptide E, cyclo-(TCVGGTCNTPGCSCSWPVCTRNGLPICGE); vary peptide F, cyclo(TCTLGTCYTAGCSCSWPVCTRNGVPICGE); vary peptide G, cyclo-(TCFGGTCNTPGCSCDPWPVCSRNGVPVCGE); and vary peptide H, cyclo-(TCFGGTCNTPGCSCETWPVCSRNGLPVCGE). The vary peptides B-H exhibited high degrees of homology with the hitherto known macrocyclic peptides vary peptide A, kalata B1, violapeptide I, circulins A and B, and cyclopsychotride A.