Argan leaves aqueous extract’s antioxidant activity and mild steel corrosion inhibition ability

The aim of this study is the valorization of Argan leaves’ Aqueous Extract (ALAE) as a potential industrial alternative for Argania spinosa kernels’ extracts. The chemical composition of ALAE was investigated by HPLC/UV-VIS/DAD and we successively identified 5 compounds in which quercetin and its derivatives represent 85.47%. We also evaluated the antioxidant activity via two assays DPPH* scavenging activity and Ferric Reducing Antioxidant Power (FRAP). The concentration required to achieve 50% of antioxidant activity is 142.53±1.26 μg/mL and 129.68±3.42 μg/mL, respectively, which was compared to standard antioxidants such as gallic acid (17.41±2.15 μg/mL, 17.01±1.35 μg/mL) and ascorbic acid (56.26±1.09 μg/mL, 37.93±0.65 μg/mL). The assessment of the corrosion inhibition of mild steel was carried out using three techniques: weight loss measurements, electrochemical impedance spectroscopy and polarization curves. Acting as a mixed type corrosion inhibitor and obeying to Langmuir adsorption isotherm, the ALAE inhibition efficiencies obtained by the three techniques are 79%, 82%, and 82%, respectively.