Investigating the impact of eugenol on the suppression of gallic acid oxidation by employing cyclic voltammetry

Abstract Gallic Acid (GA), naturally resourced in fruits, spices and several leafy vegetables including tea leaves, is a promising antioxidant, dietary supplement and therapeutic agent. However, it gets oxidized spontaneously in ambient condition causing oxidative damages to DNA and proteins. The current work sought to investigate the effect of Eugenol (Eug) on suppressing such oxidation of GA by employing Cyclic Voltammetry (CV) technique. Voltammetric analysis indicates a significant suppression of such oxidation process with increasing a small amount of Eug concentration (~ 0.1–0.4 v/v %). In the present study, platinum (Pt) working electrode has been considered instead of conventional glassy carbon electrode (GCE) due to its superior sensitivity towards GA solution. Such voltammetric results have been further investigated by absorption spectroscopy and FTIR measurements. The absorption spectrum exhibits a prominent peak due to GA at 265 nm, which is observed to diminish continuously with the addition of Eug. Further, the FT-IR spectroscopic measurements show the appearance of a characteristic ‘C-O stretching’ peak at 1021 cm− 1 on addition of Eug suggesting the possible formation of phenolic ether. The method has been extended to quantify the amount of GA content in a solution and examined by applying on an aqueous solution of arbitrary amount of GA, green tea and black tea, which are observed to agree satisfactorily with reported values. The entire study also suggests the controlled utilization of Eug in solutions containing GA to suppress its oxidation process thereby improving the health benefits of tea and other such bioconsumables.