Evaluation of Anticorrosion and Antioxidant Activities of Ethanolic Extract of Ammi Visnaga

The present work concerns the valorization of ethanolic extract of the aerial part of Ammi visnaga, as an antioxidant as well as a corrosion inhibitor for mild steel in 1 M HCl medium. The antioxidant activity was evaluated by two techniques; total antioxidant capacity and free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). The phytochemical tests were carried out by colorimetric reactions and precipitation which revealed an intense presence of tannins and Flavonoids. The total phenol, flavonoid and condensed tannin content were conducted according to the Folin Ciacalteu, Quettier-Deleu and Broadhurst methods, respectively. The results showed that the ethanolic extract of Ammi visnaga was rich of polyphenols. Ethanolic extract had a great radical scavenging activity (IC50=2.82 mg/mL) when compared to the standard BHT (IC50=0.27 mg/mL) along with a high total antioxidant capacity (82.46 mg BHT/g extract). On the other hand, the anticorrosion behavior of ethanolic extract of Ammi visnaga was conducted by electrochemical impedance spectroscopy, potentiodynamic polarization and mass-loss measurements. Polarization curves indicated that ethanolic extract of Ammi visnaga acts as mixed-type inhibitor. Impedance measurements showed that the double-layer capacitance decreased and charge-transfer resistance increased with rise of ethanolic extract of Ammi visnaga concentration and thereby increased the inhibition efficiency. The adsorption of the extracted molecules followed the Langmuir adsorption isotherm model. It was registered that ethanolic extract of Ammi visnaga exhibited both an important antioxidant and anticorrosive properties.