[摘要]：Many Violaceae plants contain cyclotides, which are plant cyclopeptides distinguished by a cyclic cystine knot motif with 28-37 amino acid residues. In the current study, four new cyclotides, vila A - D (1-4 resp), together with a known cyclotide, vary D (5), were isolated from Viola labridorica (Violaceae) A chromatography-based method was used to isolate the cyclotides, which were characterized using tandem mass spectrometry and 2D-NMR spectroscopy Several of the cyclotides showed cytotoxic activities against five cancer cell lines, i e, U251 MDA-MB-231, A549 DU145, and BEL-7402, with vila A and B (1 and 2, resp) being the most cytotoxic The isolated cyclotides showed no antibacterial activity against Staphyloccocus aureus and Candida albicans Homology modeling of the cyclotide structures was used to analyze structure-activity relationships.
