Fabrication of an Eficient Antioxidant Capacity Assay Using Peroxidase-mimicking Trivalent DNAzyme

Abstract

So far, several methods, including DPPH, FRAP, and TEAC have been suggested for considering the antioxidant capacity, each with disadvantages, including the need for expensive tools, low sensitivity, and complexity. One of the most accurate methods is the TEAC method, due to the use of protein enzymes, which possess disadvantages such as activity in the limited temperature range, and instability against hydrolysates and hard storage conditions. Therefore, antioxidant capacity measurements using the peroxidase-like trivalent deoxyribozyme used. The results showed that trivalent deoxyribozyme had more catalytic activity than monomeric deoxyribozyme. Also, kinetic parameters such as kcat, Km, and Vmax were calculated in the presence of H2O2, which equal to 4.32 (min-1), 8.744 (µM), and 0.864 (µM/min), respectively. The results of calculating RAC for the extracts of Dacrocephalum and Black cardamom plants were estimated to be 28.59 and 11.79, respectively. Also, the limit of detection (LOD) was found for Trolox, Ferulic acid, and Caffeic acid obtained about o.27, 0.14 and 0.28 (µM) by UV-vis spectroscopy. Also, LOD is 5.0, 2.0, and 2.5 (µM) by the naked eye for the mentioned antioxidants, respectively. These results indicated that antioxidant capacity measurements using the peroxidase-like trivalent deoxyribozyme have advantages such as cheapness, simplicity, observation with naked eyes, stability, and high sensitivity to the other methods.