Identification of a cyclodextrin inclusion complex of antimicrobial peptide CM4 and its antimicrobial activity

Antibacterial peptide CM4 (ABP-CM4) is a natural product isolated from the silkworm Bombyx mori. It is a small cationic peptide with broad-spectrum activities against harmful microorganisms and may be used as a novel food preservative. However, ABP-CM4 lacks tertiary structure in water-like solutions, which makes it more susceptible to proteases and labile when exposed to air. In this study, β-cyclodextrin (β-CD) was chosen to form an inclusion complex with ABP-CM4, which enhanced the physical and chemical properties of ABP-CM4 but did not decrease its antibacterial activity. The storage stability and susceptibility to proteinases of ABP-CM4 were apparently improved under the protection of β-CD. This technology could also be widely applied to other AMPs as an antimicrobial system to be used in the food industry.