KR12 peptide associated with cyclodextrin: Antimicrobial and antitumor activities

The aim of this study was to determine the physical properties and antimicrobial and antiproliferative effects of the KR12 peptide complexed with 2-hydroxypropyl-β-cyclodextrin (Hp-βCd) in vitro. The KR12:Hp-βCd composition was evaluated for particle size and its zeta (ζ)-potential in the presence and absence of cells. Antimicrobial activity against Streptococcus mutans, Actinobacillus actinomycetemcomitans, and Porphyromonas gingivalis for the peptide alone or associated was evaluated by minimal inhibitory concentration. The cytotoxicity of the peptide and composition toward fibroblasts, Caco-2 cells, and A431 cells was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; thiazolyl blue assay and hemolysis assay. Membrane integrity was analyzed by the lactate dehydrogenase assay. KR12:Hp-βCd decreased the peptide concentration required for the antimicrobial effect. Moreover, this composition was able to modify cell surface parameters, such as ζ-potential, and alter the degree of hemolysis induced by KR12. However, the KR12:Hp-βCd and KR12 alone alter the zeta potential of cells to a similar extent, suggesting a similar level of membrane interaction. The peptide alone inhibited the proliferation of Caco-2 and A431 cells more efficiently than KR12:Hp-βCd (p < 0.001), but did not show significant cytotoxic effects via the dehydrogenase lactate assay. Both substances were effective in inhibiting the growth of odontopathogenic bacteria, as well as inhibiting Caco-2 epithelial cells. These observations highlight the potential antimicrobial and antiproliferative effects of KR12 peptide alone or associated with Hp-βCd.