Discrimination and classification of ginsenosides and ginsengs using bis-boronic acid receptors in dynamic multicomponent indicator displacement sensor arrays.

Ginsenosides are complex natural products with a diverse array of biological activities, but their molecular recognition and sensing is challenging. A library of simple bis-boronic acid-based receptors with various spacers was synthesized for the sensing of ginsenosides. The incorporation of two boronic acids allowed the pairing of two indicators, which can simultaneously bind the receptors or two saccharides within the ginsenosides. A cross-reactive sensing array was therefore constructed using the receptors in conjunction with different pairs of indicators. LDA plots created from the colorimetric response of the hosts and indicator pairs reveal excellent classification of the ginsenosides, and the corresponding loading plots reveal the cross-reactivity of the receptors. In addition, several commercial ginseng extracts were unambiguously classified using the same sensing array. The assay reported here should be applicable to the analysis of other large saccharide-based natural products.