Biosynthesis of selenium nanoparticles from Dahlia pinnata tuberous roots with antibacterial, antidiabetic, and erythrocyte membrane protective activities

Selenium nanoparticles (SeNPs) synthesized using Dahlia pinnata L tuber extract exhibit significant antimicrobial, antidiabetic, and anti-inflammatory properties. This study describes the green synthesis of SeNPs using D. pinnata L. tuber extract, a sustainable approach that leverages plant-based compounds. Green synthesis was confirmed via UV-Vis spectroscopy (280 nm peak), XRD trigonal crystal structure with planes (100), (101), (110), (111), and (201), and TEM (spherical particles, 17.37 nm average size). FTIR revealed functional groups (C-H, C = O, Se-Se), while HPLC identified gallic acid (1070.58 µg/g) and chlorogenic acid (903.87 µg/g). In antimicrobial studies, SeNPs demonstrated strong efficacy against 70 Escherichia coli isolates from laboratory samples of diabetic patients. For 15 multidrug-resistant (MDR, 21.4%) isolates, SeNPs had MICs of 25-50 µg/ml (mean: 35 ± 12 µg/ml) and MBCs of 50-100 µg/ml (mean: 76.6 ± 26 µg/ml). Non-MDR isolates (78.6%) were more sensitive, with MICs of 10-25 µg/ml (mean: 15 ± 4.5 µg/ml) and MBCs of 25-50 µg/ml (mean: 35 ± 12 µg/ml), outperforming selenium precursors and vancomycin. SeNPs also showed antidiabetic potential through α-amylase inhibition (IC₅₀ = 50.32 µg/ml) and α-glucosidase inhibition (IC₅₀ = 31.55 µg/ml), though less effective than acarbose (IC₅₀ = 5.85 µg/ml and 3.93 µg/ml, respectively). In anti-inflammatory assays, SeNPs achieved dose-dependent hemolysis inhibition, with 96.0% inhibition at 1000 µg/ml and an IC₅₀ of 11.53 µg/ml, compared to indomethacin's IC₅₀ of 4.51 µg/ml. These findings demonstrate the promising in vitro bioactivities of SeNPs synthesized from D. pinnata L. tuber extract and support their potential for further preclinical investigation.