Unveiling the antioxidant and antimicrobial potential of Astragalus tephrosoides methanol extract: Phytochemical screening, GC-MS profiling, computational and experimental approaches

Background: Plant-derived bioactive compounds have significant pharmaceutical applications. Objectives: This study focused on the methanol extract of Astragalus tephrosoides (A. tephrosoides) to evaluate its phytochemical composition, biological activities and in-silico properties. Method: Phytochemical screening, GC-MS profiling, antioxidant (DPPH), antimicrobial and phytotoxic assays were performed. Molecular docking against bacterial proteins (DNA gyrase, lanosterol-14-?-demethylase, PBP2A and chitin synthase) and density functional theory (DFT) analyses were conducted for the bioactive compounds identified by GC-MS. Results: Phytochemical analysis confirmed the presence of alkaloids, steroids, terpenoids, saponins, phenolics, volatile oils and coumarins in the extract. GC-MS analysis revealed the presence of 17 bioactive compounds. The extract exhibited notable antioxidant activity (IC50 = 0.66 mg/mL), comparable to that of ascorbic acid (IC50 = 0.58 mg/mL). Antibacterial effects were observed with net absorbance values of 0.860 (E. coli, P. aeruginosa), 0.770 (B. subtilis), 0.656 (S. aureus) and 0.550 (S. typhi) and MICs of 1.0-0.12 µg/mL. The extract exhibited antifungal activity comparable to that of miconazole and moderate phytotoxicity (66.6%) at 1000 ?g/mL. Docking revealed moderate binding affinities, while DFT analysis revealed significant HOMO/LUMO gaps, indicating their thermodynamic stability. Conclusion: A. tephrosoides contains bioactive compounds with promising antioxidant, antimicrobial and moderate phytotoxic activities, as supported by computational studies.