uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Optimization of Cyclotide Extraction Parameters
Uppsala University, Disciplinary Domain of Medicine and Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy.
(English)Article in journal (Other academic) Submitted
Abstract [en]

Cyclotides are gene-encoded plant mini-proteins that contain a unique circular and cystine knotted amide backbone. Because of that ultra stable scaffold and the ability to harness a wide variety of sequences and biological activities within the scaffold, cyclotides find interesting potential applications for drug discovery and in agriculture. However, some fundamental knowledge is still missing to exploit these plant compounds including finding the optimal process of their extraction from plant material. In the current work, the extraction parameters solvent type, time of extraction, number of re-macerations and the plant material to solvent ratio have been compared using the sweet violet (Viola odorata L.) as a model plant. That species is a well-characterized and rich source of cyclotides that contains prototypic cyclotides with different chemical and physical properties. We found that hydroalcoholic solutions of medium polarity give good yield of the cyclotide cocktail. In conclusion, single maceration with 50 % MeOH for 6 h at a plant material to solvent ratio of 0.5: 10 (g/mL) represents an optimum extraction method.

Keyword [en]
cyclotide, Extraction, cycloviolacin O2, cycloviolacin O18, cycloviolacin O19, varv A, Viola odorata
National Category
Medical and Health Sciences Natural Sciences
Identifiers
URN: urn:nbn:se:uu:diva-171152OAI: oai:DiVA.org:uu-171152DiVA: diva2:510263
Available from: 2012-03-15 Created: 2012-03-15 Last updated: 2012-04-19
In thesis
1. Cyclotides: Tuning Parameters Toward Their Use in Drug Design
Open this publication in new window or tab >>Cyclotides: Tuning Parameters Toward Their Use in Drug Design
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Cyclotides are plant proteins with a unique topology, defined as the cyclic cystine knot motif. The motif endows cyclotides with exceptional chemical and biological stability. They also exhibit a wide range of biological activities including insecticidal, cytotoxic, anti-HIV and antimicrobial effects. Hence, cyclotides have become potential candidates in the development of peptide-based drugs; either as scaffolds to stabilize susceptible peptide sequences or as drugs by their own right. In this thesis, important parameters that could be inputs toward this development have been tuned.

An extraction protocol that can be extended to industrial scale production of the cyclotides from natural sources was developed; accordingly, a single maceration with hydroalcoholic solutions of medium polarity represented an optimum extraction method.

Moreover, it was shown that investigating the cyclotide content of cyclotide-bearing plants from diverse environments is a promising approach for extending the knowledge of both structural and biological diversity of these proteins. Five novel cyclotides with new sequence diversity were isolated and characterized from a violet that grows on Ethiopian highlands at an altitude of 3400 m.

One of the areas where the cyclotide framework has attracted interest is the development of stable antimicrobial peptides. A stability study was carried out to determine the stability of the cyclotide framework in a cocktail of bacterial proteases and serum where the native forms of tested cyclotides exhibited high stability profile.

Understanding the modes of cyclotide-cell interaction is certainly an important factor for the potential development of cyclotide-based drugs. Cellular studies were carried out using the comet assay and microautoradiography. A bell-shaped dose response curve was obtained for the DNA damaging effect of the cyclotides in the comet assay, which was the first toxicological assay of its kind on this class of proteins. The microautoradiography study revealed that the cyclotides penetrate into the cells even at cytotoxic concentrations. From previous reports, it was known that the cyclotides interact with membranes; the cellular studies in this thesis added to this knowledge by clearly demonstrating that these proteins have multiple modes of action. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 81 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 156
Keyword
cyclotide, Viola abyssinica, Viola odorata, Extraction, Violaceae, vaby, cytotoxic, genotoxic, cell penetrating, microautoradiography, LC-MS, comet assay, cycloviolacin O2
National Category
Medical and Health Sciences Natural Sciences
Research subject
Pharmacognosy
Identifiers
urn:nbn:se:uu:diva-169712 (URN)978-91-554-8307-4 (ISBN)
Public defence
2012-04-26, B41, Husargatan 3, Biomedical Center, Uppsala University, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2012-04-04 Created: 2012-03-05 Last updated: 2012-04-19Bibliographically approved

Open Access in DiVA

No full text

By organisation
Disciplinary Domain of Medicine and Pharmacy
Medical and Health SciencesNatural Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 438 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf