Cyclotides from Brazilian medicinal plant species Anchietea pyrifolia

Cyclotides are cysteine-rich peptides from plants with molecular mass in the range of 2.8 - 3.7 kDa, with six conserved cysteine residues involved in the formation of an unique arrangement called cyclic cystine knot (CCK) motif. This arrangement is responsible for their thermal, chemical, and enzymatic stability [1]. A. pyrifolia (Violaceae), popularly known as “cipó-suma” is a medicinal plant used by local population of Brazil as depurative and for the treatment of skin disorders [2]. Thus, in this study, the roots were extracted with a hydromethanolic mixture (6:4; v/v) for 24 hours (4 times). The hydromethanolic extract was resuspended and submitted to solid phase extraction (SPE-C18-cartridges) to obtain the rich-peptide fraction. This fraction was submitted to LC-ESI-IT-MS analysis that confirmed the presence of peptides in mass range of 2800-3700 Da. HPLC chromatography allowed to isolate five cyclotides from the roots. The peptide sequencing was performed by enzymatic digestion with endoproteinase Glu-C, trypsin, chymotrypsin and followed by MALDI-TOF-MS/MS analysis. The spectra were examined based on the presence of both b- and y-series of ions, three new cyclotides (anpy A-C) and two previously known ones (cyO4 and cyO17) were identified and their hemolytic activity tested. Anpy A was the most hemolytic with HD₅₀ of 22µM.

Publication History

Article published online:
13 December 2021

• References

• 1 Craik D.J. et al. Bioorg. Med. Chem. v. 26: 2727 2018;
• 2 Grandi T.S.M. Tratado das Plantas Medicinais. 1.ed Belo Horizonte: Adaequatio Estúdio; 1204p. 2014