Cyclotides derived from Viola dalatensis Gagnep: A novel approach for enrichment and evaluation of antimicrobial activity

• Published in: Toxicon (Oxford) 2024-02, Vol.239, p.107606-107606, Article 107606
• Main Authors: Dang, Tien T., Tran, Tam T.T., Tran, Gia-Hoa, Pham, Son H., Nguyen, Tuan H.N.
• Format: Article
• Language: English
• Subjects: ammonium sulfate; Anti-Bacterial Agents - chemistry; anti-infective agents; Antibacterial; antibacterial properties; Antifungal; Aspergillus flavus; Bacillus subtilis; Cyclotide precipitation; Cyclotides; Cyclotides - chemistry; Cyclotides - pharmacology; flavonoids; free radicals; minimum inhibitory concentration; MS tandem; peptides; Plant Extracts - chemistry; Plant Extracts - pharmacology; polyphenols; protein content; Pseudomonas aeruginosa; stem extracts; Vietnam; Viola; Viola - chemistry; Viola - metabolism
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/j.toxicon.2024.107606

Cyclotides, plant-derived cysteine-rich peptides, exhibit a wide range of beneficial biological activities and possess exceptional structural stability. Cyclotides are commonly distributed throughout the Violaceae family. Viola dalatensis Gagnep, a Vietnamese species, has not been well studied, especially for cyclotides. This pioneering research explores cyclotides from V. dalatensis as antimicrobials. This study used a novel approach to enhance cyclotides after extraction. The approach combined 30% ammonium sulfate salt precipitation and RP-HPLC. A comprehensive analysis was performed to ascertain the overall protein content, flavonoids content, polyphenol content, and free radical scavenging capacity of compounds derived from V. dalatensis. Six known cyclotides were sequenced utilizing MS tandem. Semi-purified cyclotide mixtures (M1, M2, and M3) exhibited antibacterial efficacy against Bacillus subtilis (inhibitory diameters: 19.67–23.50 mm), Pseudomonas aeruginosa (22.17–23.50 mm), and Aspergillus flavus (14.67–21.33 mm). The enriched cyclotide precipitate from the stem extract demonstrated a minimum inhibitory concentration (MIC) of 0.08 mg/mL against P. aeruginosa, showcasing significant antibacterial effectiveness compared to the stem extract (MIC: 12.50 mg/mL). Considerable advancements have been achieved in the realm of cyclotides, specifically in their application as antimicrobial agents. [Display omitted] •This research explores cyclotides from V. dalatensis, a native Vietnamese species, as antimicrobials.•The unique method enhanced extracted cyclotides with 30% ammonium sulfate salt precipitation and RP-HPLC.•Six known cyclotides were sequenced utilizing MS tandem.•M1, M2, and M3 cyclotides inhibited Bacillus subtilis, Pseudomonas aeruginosa, and Aspergillus flavus.•Cyclotide precipitate had a MIC of 0.08 mg/mL against P. aeruginosa, while stem extract had 12.50 mg/mL.