Development of apigenin monoclonal antibodies and an immunoassay for the quantification of apigenin in celery

Apigenin, a 4',5,7-trihydroxyflavone compound with diverse biological activities, is found abundantly in vegetables and fruits, particularly in celery. The identification and quantification of apigenin have become critical indicators for quality control in raw pharmaceuticals, finished drugs, and formulations. This study established an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies for the quantitative detection of apigenin in celery. The method exhibited a median inhibitory concentration (IC₅₀) of 0.45 ng/mL, with a working range of 0.15 to 1.52 ng/mL (IC₂₀-IC₈₀). It showed average recoveries of 83.6-113.7 % in celery leaf samples and 76.8-99.2 % in celery petiole samples. Moreover, the apigenin content in ten celery samples was determined using the developed icELISA and validated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). These results demonstrate that the established immunoassay is suitable for detecting apigenin in complex matrix samples, offering enhanced efficiency, sensitivity, and operational convenience compared to conventional analytical methods.