Chemical Information From GC-MS Studies of Ethanol Extract of Andrographis Paniculata and Their Corrosion Inhibition Potentials on Mild Steel in HCl Solution

GC-MS study of ethanol extract of Andrographis paniculata revealed the presence of hydrocarbons ((E)-tetradec-3-ene), alcohol (6-methyl heptan-1-ol), aromatics (undecan-5-ylbenzene, dodecan-5ylbenzene, undecan-2-ylbenzene, (2-methylundecan-6-yl) benzene and dioctyl phthalate). Some of the identified compounds were found to be green raw materials for polymer industries and pharmaceutical companies. Corrosion inhibition potentials of the ethanol extract of Andrographis paniculata was also investigated and it was found that the extract inhibited the corrosion of mild steel in HCl solution through the mechanism of physical adsorption. Quantum chemical approaches have been used to investigate the active components of the extract that are responsible for the inhibition of the corrosion of mild steel in HCl solution. The results obtained, indicated that the most active ingredient responsible for the corrosion inhibition process is pentadecanoic acid. Other compounds with lesser activity include 6-methyl hepta-1-ol, methyl palmitate, methyl icosanoate, methyl stearate, oleamide, dicotyl phthalate and ethyl docosanoate are the active.