Isolation and characterization of cytotoxic cyclotides from Viola philippica

He, Wenjun, Chan, Lai Yue, Zeng, Guangzhi, Daly, Norelle L., Craik, David J. and Tan, Ninghua (2011) Isolation and characterization of cytotoxic cyclotides from Viola philippica. Peptides, 32 8: 1719-1723. doi:10.1016/j.peptides.2011.06.016

Author He, Wenjun
Chan, Lai Yue
Zeng, Guangzhi
Daly, Norelle L.
Craik, David J.
Tan, Ninghua
Title Isolation and characterization of cytotoxic cyclotides from Viola philippica
Formatted title
Isolation and characterization of cytotoxic cyclotides from Viola philippica
Journal name Peptides   Check publisher's open access policy
ISSN 0196-9781
Publication date 2011-08
Sub-type Article (original research)
DOI 10.1016/j.peptides.2011.06.016
Volume 32
Issue 8
Start page 1719
End page 1723
Total pages 5
Place of publication Philadelphia, PA, U.S.A.
Publisher Elsevier
Collection year 2012
Language eng
Formatted abstract
Cyclotides are a large family of plant peptides characterized by a macrocyclic backbone and knotted arrangement of three disulfide bonds. This unique structure renders cyclotides exceptionally stable to thermal, chemical and enzymatic treatments. They exhibit a variety of bioactivities, including uterotonic, anti-HIV, cytotoxic and hemolytic activity and it is these properties that make cyclotides an interesting peptide scaffold for drug design. In this study, eight new cyclotides (Viphi A–H), along with eight known cyclotides, were isolated from Viola philippica, a plant from the Violaceae family. In addition, Viba 17 and Mram 8 were isolated for the first time as peptides. The sequences of these cyclotides were elucidated primarily by using a strategy involving reduction, enzymatic digestion and tandem mass spectroscopy sequencing. Several of the cyclotides showed cytotoxic activities against the cancer cell lines MM96L, HeLa and BGC-823. The novel cyclotides reported here: (1) enhance the known sequence variation observed for cyclotides; (2) extend the number of species known to contain cyclotides; (3) provide interesting structure–activity relationships that delineate residues important for cytotoxic activity. In addition, this study provides insights into the potential active ingredients of traditional Chinese medicines.

Highlights: • Eight new cyclotides were characterized from the Viola philippica. • All cyclotides were evaluated for their cytotoxic activity. • The novel cyclotides enhance the sequence variation observed for cyclotides.
Keyword Cyclotides
Cyclic peptides
Viola philippica
Cytotoxic activity
Viphi A-H
Cyclic cystine knot
Cycloviolacin O2
Circular proteins
Macrocyclic peptides
Sequence variation
Structural motif
Plant cyclotides
Kalata B1
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
Institute for Molecular Bioscience - Publications
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