Abstract Cyclotides are plant peptides, which are characterized by their unique cyclic cysteine knot structure. These peptides have a variety of biological activity including anti-HIV, anti-microbial and cytotoxic effects. In the current study, we compared these gene sequences encoding cyclotides from Viola odorata, V. ignobilis and V. occulta. We also extracted total cyclotides content from V. ignobilis by fractionation method and semipurified these on a SPE-CI8 (Solid Phase Extraction). Anti-microbial activity of the semi-purified cyclotides was determined by radial diffusion assay (RDA). Three groups of bacteria were studied including human pathogenic bacteria, plant pathogenic bacteria and soil benefit bacteria. Three gene encoding cyclotides were identified in studied species. The most susceptible bacterium in human pathogenic group was Staphylococcus aureus. Xanthomonas oryzea was the most susceptible bacterium between the three studied groups.
Keywords: anti-microbial agent; cyclotide; RDA; human and plant pathogenic bacteria; Violaceae