Preparation of monoclonal antibody against psoralen and development of an icELISA method for its quantification in Chinese patent medicines

Psoralen and isopsoralen are the key active components and quality control standards of traditional Chinese medicines such as Psoraleae Fructus. In this study, two psoralen haptens were designed and synthesized, and a psoralen monoclonal antibody (mAb 4E6) was successfully screened, which could simultaneously recognize isopsoralen with a cross-reactivity rate of 9.85%. Based on this antibody, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was established for the determination of psoralen and total psoralen and isopsoralen. The half-maximal inhibitory concentration (IC 50 ) values were 34.35 ng/mL and 152.22 ng/mL, with the working ranges of 4.22-328.92 ng/mL and 43.14-624.44 ng/mL, respectively. Recovery experiments in vitamin C tablets and Cassia seed matrices yielded recovery rates of 87.6%-93.2% and 81.6%-102.6%, respectively, demonstrating good precision. When applied to the analysis of four proprietary Chinese medicine samples, the results obtained by this method were in strong agreement with those from the reference UPLC-MS/MS method (R 2  = 0.9957). This assay offers operational simplicity and reliable accuracy, making it well-suited for rapid screening and quality assurance of psoralen-type compounds in complex samples.