Exploitation of Azadirachta indica extracts for multifunctional: antibacterial, anticorrosive, antioxidant activities, and its chemical constituents

Abstract: In this study, Azadirachta indica extract was carried out to explore the potential of new eco-friendly environmental materials. Azadirachta indica leaves were extracted with various methanol solvents (50%, 75%, and 100%) at room temperature for 3 × 24 h. Antibacterial activity was assessed using the dilution method at various concentration series. Anticorrosion performance was measured by potentiodynamic polarization on mild steel. The antioxidant property of the extract was analyzed using a DPPH assay. The chemical structure of the bioactive compound present in the extract was evaluated utilizing GC–MS and LC–MS/MS techniques. The results revealed that the antibacterial activities against Pseudomonas aeruginosa were obtained at 100% methanol with 8 mg mL⁻¹ of minimum inhibitory concentration. Azadirachta indica extract has anti-corrosion properties, which are confirmed by decreasing the corrosion rate of carbon steel by adding A. indica extract. The optimum inhibition efficiency (%η) of 91.84% was achieved at 47 °C with the addition of 1200 mg L⁻¹ of A. indica extract. Azadirachta indica also has very strong antioxidant properties (48.45 µg/mL) from the extract with methanol solvent. Those properties are related to the phytochemical content in the extract. Azadirachta indica leaf methanol extract indicated 39 peak compounds by GC–MS analysis. At the same time, LC–MS/MS evaluation results show that the structure of the compound in A. indica leaf extract consists of Quercetin-3-O-rutinoside, Quercimeritrin, and Quercetin. Based on these results, A. indica extract could be employed as an antibacterial, anticorrosive, and antioxidant material source. Graphic abstract: (Figure presented.).