Abstract:

Three coumarins with unknown sensitization in plant extracts of cosmetic were evaluated by direct peptide reaction assay （DPRA）. Three coumarins were incubated with skin proteins simulated by cysteine polypeptide and lysine polypeptide. The percentage of peptide consumption of the three coumarins was detected by HPLC. Under standard chromatographic conditions, the peak type of the reaction system of osthole and escoparone with the two peptides was normal, while the peak type of the reaction system of scopoletin with lysine was abnormal. The standard mobile phase system was optimized by 0.1% formic acid-acetonitrile mobile phase system. The results show that the reaction system of osthole and cysteine precipitates 24 h before the reaction, and the sensitization result is uncertain. The average percentage of peptide consumption of escoparone is 6.95%, which indicates that the sensitization is positive and the reaction grade is weak. The cysteine peptide consumption of scopoletin is 75.82%, and the lysine peptide consumption is 80.46% after the optimized chromatographic conditions. It is determined that the sensitization is positive and the reaction grade is moderate. The results of positive and negative control compounds are consistent with the results of LLNA sensitization. The experimental results can provide reference and basis for the sensitization of 3 coumarins.

Key words: direct peptide reaction assay, skin sensitization, high performance liquid chromatography, coumarin