# Evaluation of Antioxidant and Anticorrosive Activities of _Ceriops_ _tagal_ Plant Extract
###### Abstract  
Mangroves are plants known for their various medicinal and economical values, and therefore are widely investigated for their phytochemical, antioxidant, antidiarrheal, and antimicrobial activities. In the present study, we analyze the antioxidant and anticorrosive properties of _Ceriops_ _tagal_ (_C. tagal_), a tropical and subtropical mangrove plant of the Rhizophoreaceae family. The total phenolic content (TPC) and total flavonoid content (TFC) were found to be 101.52 and 35.71 mg/g, respectively. The extract (100 \(\upmu\)g/mL) exhibited 83.88, 85, and 87% antioxidant property against 1,1-diphenyl-2-picrylhydraz (DPPPH), nitric oxide, and hydrogen peroxide free radicals. In addition, 600 ppm of _C. tagal_ extract showed 95% corrosion inhibition against 1 M HCl attack on mild steel at 303 \(\pm\) 1 K, which declined over other concentrations and temperatures, where AAS produced 82% inhibition at 600 ppm. UV-visible spectroscopy analysis revealed the formation of an inhibitor metal complex. The elemental analysis provided the presence of 84.21, 9.01, and 6.37% of Fe, O, and C, respectively, in inhibited mild steel, whereas the same were 71.54, 22.1, and 4.34%, respectively, in uninhibited specimen, stressing the presence of protective film on the metal surface. Scanning electron microscopy (SEM) also showed some noteworthy changes in both uninhibited and inhibited mild steel, making _C. tagal_ plant a better alternative than any other synthetic inhibitors. Further, the atomic force microscopy (AFM) surface topography analysis showed that 600 ppm of _C. tagal_ extract significantly diminished corrosion on the surface of mild steel. Ceriops_ _tagal_; antioxidant; corrosion inhibition; mild steel; SEM-EDX; AFM +
Footnote †: journal: Medical  
been reported as food additives, anti-atherosclerotic, antioxidant, anti-ageing, antitumor, anti-cholinergic, antimicrobial, analgesic, and anti-inflammatory agents from _Avicennia marina_ (Forssk.) Vierh [7]. Apart from this, plants such as _Laguncularia racemosa_ L., metformin from _Galega officinalis_ L., _Avicennia germinans_ L., _Bruguiera gymnorhiza_ L., _Rhizophora muconate_, and _Rhizophora mangle_ are often used as insecticides and protein kinase inhibitor, anticancer, anti-ulcer, anti-inflammatory, antidiabetic, antioxidant, analgesic, anti-cholinesterase, anti-hemorrhage, antimicrobial, and wound healing products [8; 9; 10]. In addition to the plants, microbes associated with mangroves, for instance, _Codium fragile_, halophilic bacteria, actinomycete, and _Nocardiia_ sp., have been recognized as powerful anticoagulant, polyketide synthases (resveratrol, erythromycinycin, and lovastatin), anti-infection, and 2-pyronone derivatives [11]. In addition to the biological activities, plant compounds have been established as excellent corrosion inhibitors against aggressive mediums (acid and alkaline solutions) to protect metals and alloys replacing other inorganic and synthetic inhibitors as they are expensive and have proven to be toxic to the environment and humans. Interest in green inhibitors has consistently increased since 1950, which has majorly focused on plants extract and other plant-derived compounds as corrosion inhibitors. To name a few, R-(+)-pulegone from pennyroyal oil (_Mentha pulgeium_), Aloe vera, _Mangifera indica_, natural polymers (mimosa tannin and guar gum), model green inhibitors (tryptophan and glutamic acid), allyl propyl disulfide (garlic), alkaloid berberine (mustard seeds), monomtrene 1,8-cineole (_Eucalyptus_ oil), amines and bioflavonoids (_Garcinia kola_), and flavonoids, amino acids, and pigments (calyx extract) have been identified as effective corrosion inhibitors [12; 13]. There is evidence that explains the role of double or triple bonded heteroatoms and high-density electrons such as oxygen, sulfur, phosphorus, and nitrogen in organic compounds in inhibiting corrosion through their impressive adsorption tendency [14].