Fragment antigen-binding (Fab) antibody-based lateral flow immunoassay for rapid and sensitive detection of potent phytoestrogen, deoxymiroestrol

Pueraria candollei is an ingredient of Thai herbal medicine, dietary supplements, and cosmetics. The in vitro and in vivo studies of this plant supported anti-osteoporotic activity and used for hormone replacement therapy. Deoxymiroestrol shows the most potent phytoconstituent in tuberous root of P. candollei with estrogenic activity. The quality controls are important for good agricultural practice (GAP) and good manufacturing practice (GMP) of plant-derived raw materials. The rapid detection of lateral flow immunoassay (LFIA) using colloidal gold is simply method, easy visualize detection and produce less waste than conventional chromatographic detection. In this study, LFIA for qualitative detection of deoxymiroestrol using antigen-binding fragment antibody (Fab) was developed. The result showed that the developed LFIA displays specific detection of deoxymiroestrol. Cross reactivity of this method was analyzed with miroestrol, isomiroestrol and methylisomiroestrol which showed 39.97%, 7.71% and 5.72%, respectively. After optimal condition, limit of detection (LOD) for deoxymiroestrol is 250 ng/ml. Plant samples were applied to strip test compare with indirect competitive ELISA using polyclonal antibody to confirm the application of LFIA. The results of LFIA method were comparable with those from ELISA. This developed lateral flow immunoassay can apply to detect deoxymiroestrol for the rapid testing. The developed method can use for quality control in plant samples as deoxymiroestrol is biomarker compound in P. candollei. Graphic abstract: [Figure not available: see fulltext.]