DEVELOPMENT AND QUANTIFICATION OF HORSERADISH PEROXIDASE USING PARAPHENYLENEDIAMINE AND ALPHA NAPHTHOL: APPLICATIONS IN MEDICINAL PLANT SOURCES

In this work, a unique calorimetric system was presented for the determination of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). This HRP-catalyzed system is based on the formation of electrophilic 1,4 –diimine by the oxidation of Paraphenylenediamine (PPD), this intermediate undergoes coupling with the free para position of Alpha naphthol (AN) to generate the stable intense purple-colored radical with λmax 520nm had good linear with peroxidase concentration 0.08-1.32 nm and 0.02-0.66 nm by kinetic and one-time detection method and H2O2 amid 0.6 – 38.7 µM from the kinetic and 0.07- 4.83 µM by fixed time method, respectively. Moreover, the applicability of the proposed PPD-AN system has been successfully used to detect HRP activity in medicinal plants with crude extract as the source of enzyme and the outcomes were compared with the reference method. Overall, the present system can be adopted as a candidate system for the determination of H2O2.