Highly efficient complexation of sanguinarine alkaloid by carboxylatopillar[6]arene: pKa shift, increased solubility and enhanced antibacterial activityElectronic supplementary information (ESI) available: 2D NOESY spectrum, UV-vis spectra, determination of the association constants, antibacterial assay, etc. See DOI: 10.1039/c7cc02799k

Encapsulation of a physiologically active substance, sanguinarine (SA), by a water soluble carboxylatopillar[6]arene (CP6A), is described. The efficient complexation by CP6A, giving a K a value of (2.4 ± 0.3) × 10 5 M −1 in pH 7.4, served to increase the water solubility by 4.3-fold, cause a 2.02 shift in p K a , and enhance the antibacterial activity of SA. Efficient complexation of sanguinarine by carboxylatopillar[6]arene. The p K a shift, increased solubility, and enhanced antibacterial activity are described.