Comparison of ethanolic extracts of phytoestrogenic Dendrolobium lanceolatum and non-phytoestrogenic Raphanus sativus to mediate green syntheses of silver nanoparticles

Green synthesis of silver nanoparticles (AgNPs) mediated by plant extracts has drawn many research interests due to its simple, cost-effective, and eco-friendly approach. However, the extracts derived from phytoestrogenic plants that produce high phenolic-based compounds exhibiting the estrogenic activity have not yet investigated. This work reported the comparison of ethanolic extracts derived from phytoestogenic Dendrolobium lanceolatum and non-phytoestrogenic Raphanus sativus to facilitate the green synthesis of AgNPs. The total phenolic content and the reducing activity of D. lanceolatum extract were significantly higher than those of R. sativus extract. In addition, the formation of AgNPs could detect in the reaction using D. lanceolatum extract, but not R. sativus extract, as determined by the characteristic surface plasmon resonance peak of AgNPs at 416 nm. The synthesized AgNPs were spherical with an average diameter of 74.60±17.11 nm, which their face-centered cubic structure of silver was confirmed by X-ray diffraction analysis. Moreover, the synthesized AgNPs exhibited the antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The results of this work, thus, suggested the potential uses of phytoestrogenic plants as a good source of reducing and stabilizing agents for the production of AgNPs and other metallic nanoparticles.