Antioxidant and Antibacterial Activity of Essential Oil of Syzygium aromaticum (L.) Merr. & L. M. Perry and its Application as EcoFriendly Copper Corrosion Inhibitor

Abstract

In this study, the essential oil of commercial clove (Syzygium aromaticum L. Merr. & L. M. Perry) was isolated. The chemical composition of the clove essential oil (CEO) was analyzed by GC-FID/MS. The reducing ability was analyzed by Ferric Reducing Antioxidant Power (FRAP) assay, while the free radical neutralization efficiency was tested by DPPH Radical Scavenging Assay. Antibacterial screening was analyzed on reference bacterial strains by diffusion test. The potential impact of CEO as a copper corrosion inhibitor was investigated by electrochemical frequency modulation (EFM), taking into account that compounds that have antibacterial and antioxidant effects also affect metal corrosion. GC-FID/MS analysis confirmed the high presence of eugenol (74.41%), (Z)-isoeugenol acetate (13.18%) and (E)-β-caryophyllene (10.60%) in CEO. The content of polyphenols is extremely high and correlates with the results of antioxidant activity. The essential oil was found to be highly effective in inhibiting the growth of the tested bacterial strains, at test concentrations of 40 and 80 mg/mL The inhibition zones of CEO were generally larger than those of the control antibiotics. The EFM results show that CEO acts as an effective inhibitor of copper corrosion in NaCl solution with a concentration of 0.5 mol/L, where it is adsorbed on the surface by physisorption according to the Langmuir adsorption isotherm.