A Porous Tantalum-Based Metal–Organic Framework (Tα-MOF) as a Novel and Highly Efficient Peroxidase Mimic for Colorimetric Evaluation of the Antioxidant Capacity

Abstract

Antioxidants are real free radical scavengers that play a shielding role against the oxidative damages related to some chronic diseases and food deprivation. Old-fashioned approaches to display the radical scavenging ability of antioxidants involve the high-cost appliance and sophisticated production procedure. In this project, we statement a new, simple and colorimetric method based on Tantalum (Ta) metal–organic nanomaterials to identify the radical-scavenging capability of antioxidants. In this approach, peroxidase mimicking MOF catalyzes the oxidation of TMB (Tetramethyl benzidine) by H2O2 to produce blue TMB radical, which can be scavenged by antioxidants compounds subsequent in color reduction. The apparent Km of Tα-MOF is measured 3.180 mM and 0.0109 µM for TMB and H2O2, respectively. In this study, the LOD values for Ferulic acid, Tannic acid, and Chlorogenic acid were 0.19, 0.06, and 0.11, respectively. The RAC value obtained for tannic acid, orange juice, and lemon juice was 4.79, 3.37, and 3.53, respectively. Relatively, the extracts lead to a discoloring tendency in the order of Lemon Juice > Orange Juice > Eucalyptus > Cichorium intybus > Thymes > Morus, indicating the best hydroxyl radical scavenging capacity of Lemon Juice. In overall, results show a favorable approach for the evaluation of the antioxidant capacity of biological juice.