The Study of Antimicrobial Activities of Partially Purified Cyclotide Content and Crude Extracts from Viola tricolor

Background: Searching for the potent natural antibiotics will improve the treatment of most infectious diseases. Cyclotides are potent active peptides derived from some plant families like Violaceae. Viola tricolor (the pansy) has been found to have numerous cyclotides. Nowadays cyclotides attract more attention for their antibacterial activities. The current research studied the antimicrobial properties of semi-purified cyclotides from V. tricolor. Methods: Extraction and purification of cyclotides from Iranian Viola tricolor were performed by fractionation and solid phase extraction methods, and their antimicrobial effects were studied against several bacterial strains using diffusion assays. Also, attendance of cyclotide in the extract was verified by Tricine-SDS page and spectroscopic methods. Results: Antimicrobial effects of semi-purified cyclotides and crude extracts resulted in the antibacterial activity potential of V. tricolor totally extracted samples against gram negative bacteria, E.coli and P. aeruginosa. However, there is need for optimizing the assay method and the culture media. Conclusion: Viola tricolor as a remedy represents the antibacterial potential, which may not be unrelated to its cyclotide content although the effectiveness of cyclotides may also differ because of their synergism, natural structure and bioactivities, the amount of purified content, and the way they were assayed.