Monoclonal antibody-based immunoassay for the specific quantification of licochalcone A: an active chalcone in licorice

ABSTRACT Licochalcone A (LicoA), which is found in the root of Chinese licorice (Glycyrrhiza inflata Batalin), has been reported as an effective anti-microbial and anti-inflammation and was approved for the treatment of rosacea and acne in clinical therapeutic. To develop a monoclonal antibody against LicoA, a mannich reaction hapten conjugate was used for immunization, followed by the hybridoma technique. Enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of LicoA was developed using a constructed antibody. The assay validation results were highly specific for the target compound, but minimally cross-reactive with the structure-related substances. After optimal conditions, the detection limit was 4.32 ng/mL and the quantification limit was 6.84–107.21 ng/mL. As a result, the developed ELISA was applied to determine the concentration of LicoA in raw licorice and marketed samples. This assay will aid in the quality control of licorice and derived products, as it can be used to identify plant species and determine bioactive markers.