Bio-green method for synthesis of nanoparticles is advantageous compared to chemical and physical methods by virtue of being ecological friend and of comparable lower cost, the present study aimed the synthesis of silver nanoparticles for two Phlomis
species (P. aurea
Decne and P. floccosa
D.) crude methanol extracts to give their nanoparticles’ extracts (PAAgNPs and PFAgNPs), they were characterized using UV/Vis spectrophotometer, Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) where formation and stability of the reduced silver nanoparticles in colloidal solution was monitored by UV/Vis spectrophotometer, the gained nanoparticles were more predominantly spherical in shape with an average particle size of 30 nm.
Green synthesized nanoparticles’ extracts (PAAgNPs and PFAgNPs) showed more total phenolic compounds (64.96±2.90, 62.40±2.85 & 51.73±2.75, 49.33±2.71), flavonoid (32.16±2.05, 29.43±1.95 & 29.50±2.25, 27.58±2.14), phenylethanoid glycosides (21.40±1.51, 22.85±1.92 & 18.25±1.46, 18.60±1.25) and iridoid (11.03±1.02, 10.15±0.88 & 9.40±0.95, 8.65± 0.72) contents for P. aurea Decne and P. floccosa D. respectively.
The nanoparticles’ extracts exhibited enhanced antioxidant potentials in dose dependent manner at two dose levels 50 and 100 µg ml-1 against stable DPPH radical (2, 2- diphenyl-1-picrylhydrazyl) using butyl hydroxyl toluene (BHT) as a reference standard, the gained results were as follows; 67.83 ± 2.77, 62.05 ± 3.96 & 55.45 ± 2.52, 49.24 ±2.65 and 95.50 ± 1.84, 93.05 ± 1.75& 88.44 ± 3.90, 84.45 ± 1.51 for P. aurea Decne and P. floccosa D. respectively, moreover, the assessment of cytotoxic activity towards three cell lines namely HEP-G2, HCT-116 and MCV-7 using Cisplatin as a reference anticancer drug reported the significant selective reduction of IC50 of the nanoparticles' extracts compared to the crude methanol extracts.
The overall results revealed that elevation of the level of different constituents in the nanoparticulated extracts was correlated to significant increase in their antioxidant potentials and cytotoxic activity which suggested the possible involvement of the phytochemical constituents in the prepared silver nanoparticle.