Cyclotides from Violaceae: Isolation, characterization, and potential applications

Abstract Cyclotides are cyclic polypeptides consisting of 28 to 37 residues, distinguished by six cysteine residues organized in a specific arrangement of three disulfide linkages. This distinctive structure provides remarkable structural stability and resilience to biological deterioration, thermal stress, and chemical denaturation. Cyclotides in plants function as a natural defense mechanism against pests. Cyclotides exhibit various biological actions that could be applied in agriculture and pharmaceuticals. Numerous cyclotides have been discovered in plant families including Violaceae, Rubiaceae, Solanaceae, Cucurbitaceae, Poaceae, and Fabaceae. They are predominantly located in Violaceae, succeeded by Rubiaceae, with limited occurrences in other families. The Violaceae family, with 98% of species categorized within the genera Viola , Rinorea , and Hybanthus , exhibits notable diversity in Vietnam. Although the Viola genus is prevalent, Rinorea also has considerable species diversity. Despite the abundance of Violaceae species in Vietnam, there is a significant deficiency in studies about extracting natural chemicals from this family. These studies underscore the relevance of cyclotide research by highlighting their extensive potential across multiple domains and emphasizing the necessity of advancing such research, especially in Vietnam.