Plant extracts have been regarded as "green" alternatives as inhibitors for metal corrosion prevention and mitigation. Therefore, understanding the electrochemical properties and the reaction mechanisms of the electroactive compounds from the plant extracts is necessary to further explore the mechanism and application of the plant extract-based additives for corrosion prevention and mitigation. Among different plant derived chemicals, aromatic compounds are among the most effective for corrosion inhibition and mitigation. Thus, the electrochemical properties of seven aromatic active compounds from the plant extracts caffeic acid, thymol (2-isopropyl-5-methylphenol, IPMP), gallic acid (3,4,5-trihydroxybenzoic acid), tannic acid, lawsone (2-hydroxy-1,4-naphthoquinone), wedelolactone, and ellagic acid are studied using multiwalled carbon nanotube modified glassy-carbon electrode, and reported to enhance the fundamental understanding of their redox behavior at different environmental pH conditions.