GC-MS-Based Phytochemical Profiling and Anti-Oxidant Potential of Lagerstroemia Speciosa Leaf Extracts and Their Synthesized Gold Nanoparticles.

Lagerstroemia speciosa is widely utilized for various ailments, including anticancer, cardiovascular, nephroprotective, hypertension, anti-diabetic, etc. Phytochemical analysis of the different solvents and the SFE extracts was performed using GC-MS, and the comparative antioxidant potential, along with the green-synthesized gold nanoparticles, was investigated. GC-MS analysis revealed the presence of major bioactive compounds, viz. mequinol, catechol, 4-hydroxy-3-methylacetophenone, ethane-dioic acid, aspidospermidin-17-ol, D-limonene, and dodecanoic acid, that contribute to the antioxidant potential of the plant. Green-synthesized Au-NPs exhibit an absorption peak at 530 nm, demonstrate good stability, and have a surface charge of -32.5 mV, as characterized by zeta potential. They were crystalline in nature, spherical in shape, and had a size range of 1-100 nm. Antioxidant evaluation using the DPPH method demonstrated the radical quenching activity of 71.01% ± 3.12% at 40 µg/ml in the methanol extract and 64.43% ± 2.1% in the SFE, while in the ABTS assay, scavenging activity of 95.27% ± 0.62% at 40 µg/ml was reported in the aqueous extract, 79.10% ± 2.9% in methanol and 50.41% ± 1.52% in AuNPs as compared to the standard compound, ascorbic acid. The high scavenging potential is likely due to the high concentration of phenolic and flavonoid compounds reported through GC-MS analysis. Further studies are needed to isolate the bioactive compounds.